COMMISSION STAFF WORKING DOCUMENT EVALUATION Council Directive 86/278/EEC of 12 June 1986 on the protection of the environment, and in particular of the soil, when sewage sludge is used in agriculture
Date: 2023-05-22
Institutions: Directorate-General for Environment, European Commission
Subjects: environmental protection, environmental standard, farming sector, sewage sludge, soil conditioning, soil protection, waste management

EN 

  EN 

   EUROPEAN COMMISSION  Brussels, 22.5.2023  SWD(2023) 157 final  COMMISSION STAFF WORKING DOCUMENT  EVALUATION  Council Directive 86/278/EEC of 12 June 1986 on the protection of the environment, and in particular of the soil, when sewage sludge is used in agriculture              {SWD(2023) 158 final}  
 
 
TABLE OF CONTENTS 

TABLE OF CONTENTS ................................................................................................................................ 1 

GLOSSARY ................................................................................................................................................... 3 

1. 

INTRODUCTION ................................................................................................................................. 4 

1.1. 

Purpose of the evaluation .............................................................................................................. 4 

1.2. 
Scope ............................................................................................................................................. 5 
1.3.  Methodology, robustness and limitations ...................................................................................... 5 

2.  WHAT WAS THE EXPECTED OUTCOME OF THE DIRECTIVE? ................................................ 6 

2.1. 

2.2. 

Description of the intervention and its objectives.......................................................................... 6 

Point(s) of comparison................................................................................................................... 9 

3.  HOW HAS THE SITUATION EVOLVED OVER THE EVALUATION PERIOD? ....................... 11 

3.1. 

3.2. 
3.3. 

National limit values and requirements at national level ............................................................. 11 

Enforcement of the Directive....................................................................................................... 14 
Sludge production and use ........................................................................................................... 14 

3.4. 
Different types of treatment and uses of sludge........................................................................... 16 
3.5.  Metal concentrations in sludge used in agriculture and in soils where it is used ......................... 18 

4. 

EVALUATION FINDINGS................................................................................................................ 19 

4.1. 

To what extent was the Directive successful and why? ............................................................... 19 
Effectiveness ....................................................................................................................... 19 

4.1.1. 

4.1.2. 

4.1.3. 

Efficiency ............................................................................................................................ 25 

Coherence ........................................................................................................................... 36 

4.2. 
4.3. 

EU added value ............................................................................................................................ 45 
Relevance .................................................................................................................................... 47 

5.  WHAT ARE THE CONCLUSIONS AND LESSONS LEARNED? ................................................. 53 

5.1. 

Conclusions ................................................................................................................................. 53 
Effectiveness ....................................................................................................................... 53 

5.1.1. 

5.1.2. 

5.1.3. 

5.1.4. 

5.1.5. 

Efficiency ............................................................................................................................ 54 

Coherence ........................................................................................................................... 55 

EU added value ................................................................................................................... 56 

Relevance ............................................................................................................................ 56 

5.2. 

Lessons learned ........................................................................................................................... 56 

ANNEX I. PROCEDURAL INFORMATION ............................................................................................. 59 

ANNEX II. METHODOLOGY AND ANALYTICAL MODELS USED ................................................... 62 

ANNEX III. EVALUATION MATRIX AND, WHERE  RELEVANT, DETAILS ON ANSWERS TO 

THE EVALUATION QUESTIONS (BY CRITERION) .................................................................... 72 

1.1 
1.2 

Evaluation matrix ........................................................................................................................ 72 
Brief answers to the evaluation questions (EQs) and details of the evidence-base ..................... 89 

ANNEX IV. OVERVIEW OF BENEFITS AND COSTS .......................................................................... 108 

ANNEX V. STAKEHOLDERS CONSULTATION - SYNOPSIS REPORT ............................................ 114 

1 

 
 
ANNEX VI. OVERVIEW OF THE REQUIREMENTS OF THE SEWAGE SLUDGE DIRECTIVE ..... 128 

ANNEX  VII.  KEY  CONCLUSIONS  RELATED  TO  THE  SSD  FROM  THE  2014  EX-POST 

EVALUATION STUDY ................................................................................................................... 131 

ANNEX VIII. LIST OF REFERENCES .................................................................................................... 133 

2 

 
 
 
 
 
 
 
Term or acronym  Meaning or definition 

Term or acronym  Meaning or definition 

GLOSSARY 

AD 

ANSES 

BWD 

CEAP 

CEC 

CIS 

CO2-eq 

COD 

DEHP 

ECJ 

EIA 

EPA 

E-PRTR 

Anaerobic Digestion 

Agence nationale (française) de 
sécurité sanitaire de 
l’alimentation, de l’environnement 
et du travail 

ND 

NVZ 

Nitrates Directive 

Nitrate Vulnerable Zone 

Bathing Water Directive 

MS 

Member State 

Circular Economy Action Plan 

PAH 

Polyaromatic hydrocarbons 

p.e. 

Population equivalent 

PFAS 

Perfluoroalkyl substances 

PCBs 

Polychlorinated Biphenyls 

Contaminant of emerging 
concern 

Common Implementation 
Strategy 

Carbon dioxide equivalent 
[a metric used to compare emissions 
from various greenhouse gases  (other 
than CO2, e.g. methane) on basis of 
their global-warming potential, by 
converting amounts of other gases to 
the equivalent amount of CO2 with the 
same global warming potential 

Chemical Oxygen Demand 

PCDD 

Polychlorinated dibenzodioxins 

di(2- ethylhexyl) phthalate 

SSD 

 Sewage Sludge Directive 

European Court of Justice 

STRUBIAS 

Struvite, Biochar and Ash-Based 
products 

Environmental Impact Assessment 

tDS 

Ton of Dry Sludge 

Environmental Protection Agency 

tDM 

Ton of Dry Matter 

European Pollutant Transfer and 
Release Regulation 

UWWT 

Urban Wastewater treatment 

EQS 

Environmental Quality Standard 

UWWTD 

Urban Wastewater Treatment 
Directive 

EQSD 

IED 

JRC 

MS 

MSFD 

Environmental Quality Standard 
Directive 

WWTP 

Wastewater treatment plant 

Industrial Emissions Directive 

WWT 

Wastewater treatment 

Joint Research Centre 

Member State 

Marine Strategy Framework 
Directive 

WFD 

WIND 

WTE 

3 

Water Framework Directive 

What if no Directive scenario 

Waste-to-energy 

 
 
1 

1. 

INTRODUCTION 

1.1  1.1.  Purpose of the evaluation 

Sewage sludge is  a mud-like residue resulting from  the treatment  of wastewater.  It  contains 
valuable organic matter and nutrients such as nitrogen and phosphorus, and therefore can have 
useful applications as a fertiliser or soil improver. Sewage sludge also contains heavy metals 
and other contaminants such as chemicals or pathogens, e.g. viruses and bacteria, which can 
potentially pose risk to the soil and to the human health (when humans ingest food products 
grown onto farmland which has been fertilised by sewage sludge) as a result of its application 
on soil. 

The Sewage Sludge Directive (hereafter, the SSD or the Directive) was adopted to encourage 
the  correct  use  of  sewage  sludge  in  agriculture  and  to  regulate  its  use  in  order  to  prevent 
harmful effects on soil, vegetation, animals and humans. However, there are other alternative 
uses  to  sludge  (see  section  2.4),  which  are  not  regulated  by  the  SSD  or  any  other  EU  level 
legislation beyond the Urban Wastewater Treatment Directive (UWWTD). 

Since  its  adoption  in  1986,  the  Directive  has  not  undergone  any  substantial  revision1. 
However, the sector of sludge management has evolved considerably. The Directive on Urban 
Wastewater  Treatment  of  1991  introduced  requirements  for  more  systematic  and  more 
advanced treatment  of wastewater, resulting in  the increase of sludge production. There has 
also  been  an  evolution  in  sludge  treatment  technologies  as  well  as  in  the  knowledge  of 
contaminants which it can contain and its impacts. Sludge management routes other than use 
in agriculture have also developed, for instance, the use of it for energy recovery. 

There have also been considerable changes in the European Union (EU) policy and regulatory 
framework.  The  revised  Directive  on  waste2  and  various  initiatives3  developed  under  the 
umbrella  of  the  European  Green  Deal4,  the  Updated  Bioeconomy  Strategy5,  EU  Circular 
Economy  Action  Plans  adopted  in  2015  and  20206  emphasize  the  economic  and 
environmental  benefits  of  recovery  of  sewage  sludge,  notably  the  recovery  of  nutrients  in 
agriculture, while stressing the need to do this safely. These policy objectives go hand in hand 
with  the  Union’s  industrial  policy7  aiming  to  further  its  independence  on  extraction  and 
imports of certain raw materials, notably phosphorus, identified as a critical raw material for 
the  Union8  and  with  regard  to  which  sewage  sludge  is  an  alternative  source.  While  not 

1 Changes made (through amendments done in 1991, 2003, 2009, 2018 and 2019) have related to reporting requirements and 

to setting a committee to assist the Commission on technical progress.  

2 Council Directive 75/442/EEC  on waste was repealed by Directive 2006/12/EC, then by Directive 2008/98/EC, currently in 

force and last revised in 2018 by Directive (EU) 2018/851  

3  This  includes  notably:  the  Bioeconomy  Strategy,  the  new  Fertilising  Products  Regulation  of  2019,  the  Farm  to  Fork 
Strategy, Zero Pollution Action Plan, Soil Strategy, the EU Biodiversity Strategy for 2030 and the on-going revision of 
the Urban Wastewater Treatment Directive. 

4 COM(2019)640 final of 11.12.2019. 
5  European  Commission,  Directorate-General  for  Research  and  Innovation,  A  sustainable  bioeconomy  for  Europe: 
strengthening  the  connection  between  economy,  society  and  the  environment  :  updated  bioeconomy  strategy, 
Publications Office, 2018, https://data.europa.eu/doi/10.2777/792130 

6 COM(2015) 614 final of 2.12.2015, COM(2020)98 final of 11.3.2020.  
7 COM(2021)350 final of 5.5.2021. 
8 COM(2020)474 final of 3.9.2020. 

4 

 
 
                                                 
regulated  by  the  SSD,  sewage  sludge  has  other  uses,  in  particular,  as  source  of  energy 
contributing to  the energy  independence of the Union,  an objective also  at  the centre of the 
proposal  for  a  revised  Urban  Waste  Water  Treatment  Directive  91/271/EEC  (hereafter,  the 
UWWTD)9. 

In 2014, the Directive was evaluated as part of an "Ex-post evaluation of certain waste stream 
directives10", which identified a number of shortcomings, largely related to the fact that it had 
been adopted 30 years earlier. The identified issues concerned the SSD contribution to the EU 
circular economy ambitions, pollutants in sludge, the potential need to regulate other uses of 
sewage  sludge,  and  the  potential  impact  of  the  revised  UWWTD.  In  view  of  the  various 
policy and regulatory developments, the Circular Economy Action Plan of 2020 called for a 
new evaluation of the Directive to validate and complement the results of the 2014 evaluation, 
to take account of the changed policy and legal landscape, and inform a possible decision to 
review the Directive.  

1.2  1.2.  Scope 

In line with the Commission's better regulation policy, this report assesses the Sewage Sludge 
Directive along five criteria: 

-  Effectiveness:  looking  into  the  extent  to  which  the  actions  defined  under  the  Directive 

have been implemented and whether this has resulted in achieving its objectives 

-  Efficiency:  assessing  whether  the  obligations  arising  from  the  implementation  of  the 

Directive have been implemented in a cost-effective way 

-  Coherence:  assessing coherence of the  Directive with  the EU wider policy objectives of 
the  European  Green  Deal  as  well  as  possible  inconsistencies  and  overlaps  with  other 
legislation 

-  EU  added  value  of  the  Directive  compared  to  what  Member  States  could  have  reached 

acting alone 

-  Relevance:  assessing  whether  the  objectives  and  the  regulatory  tools  of  the  Directive 
match  current  needs  in  view  of  the  wider  EU  policy  objectives,  notably  on  circular 
economy, sustainability, resource efficiency and climate change. 

This evaluation assesses these criteria in all Member States since the adoption of the SSD. 

It covers the whole lifetime of the Directive, since its adoption in 1986 until now, although a 
strong  focus  is  made  on  the  period  2007-2018,  as  only  limited  data  are  available  pre-2007. 
The focus of the evaluation is also driven by the changes in the policy regulatory landscape, 
which  have  changed  most  considerably  in  the  last  few  years.  On  top  of  that,  the  2014 
evaluation already provided some assessment for the pre-2014 period.  

1.3  1.3.  Methodology, robustness and limitations 

The following sources of information were used for this evaluation: 

-  A review of existing literature, including the previous evaluation and reports from relevant 

EU funded research projects.  

9 COM(2022) 541 final 
10 BioIntelligence Service et al, (2014)  

5 

 
 
                                                 
-  Member  States  implementation  reports  and  data  from  Eurostat  and  from  the  European 

Environmental Agency. 

-  Additional data to those referred to above and information on the stakeholders perception 
of  the  extent  to  which  the  SSD  has  been  successfully  implemented  and  its  relevance 
gathered  through  different  stakeholder  consultation  activities.  This  included  an  online 
public consultation (OPC), targeted surveys and interviews (with expert stakeholders and 
with  Member  States)  and  a  stakeholder  workshop.  A  wide  range  of  stakeholders 
including  Member  State  Competent  Authorities,  Non-Governmental 
contributed, 
farming  community  and  Trade 
Organisations 
Associations. Trade Associations include the agricultural sector, to which specific efforts 
were made to reach out. More detail on stakeholder consultation is provided in Annex V. 

research  organisations, 

(NGOs), 

Overall, the level and quality of evidence gathered is varied. For some evaluation criteria, in 
particular  relevance  and  coherence,  the  evidence  gathered  was  robust  and  satisfactory. 
Availability and quality of data was a challenge affecting in particular the assessment of the 
effectiveness  and  efficiency  criteria.  The  following  difficulties  have  complicated  the 
assessment:  

a more general lack of data from Eastern Member States, 

-  data on costs and benefits are scarce, and date from quite a few years back, 
- 
-  when  available,  the  datasets  on  the  use  of  sewage  sludge  in  agriculture  presented 
several  gaps,  and  in  some  instances  conflicting  information,  for  instance  between 
Member States implementation reports and Eurostat data. This made it challenging to 
derive trends in the use of sewage sludge over time for example, 

-  The response from the farming sector has been somewhat limited. In addition, it had 
been challenging to single out and identify their specific feedback in the consultation 
(in spite of the effort made to reach out to the agricultural sector as explained above). 

These  data  gaps  and  inconsistencies  were  addressed  through  specific  interviews  with 
stakeholders  (notably  for  the  efficiency  section),  or  by  completing  datasets  with  data  from 
other sources and extrapolations. For instance, the data reported by Member States under the 
implementation of the SSD was used as the main data set and observed gaps were filled using 
Eurostat  data.  Where  there  remained  too  many  data  gaps,  for  instance  for  a  given  Member 
State for a given year, extrapolations were made based on reporting done from other years and 
population  size.  Information  gathered  from  different  sources,  including  input  from 
stakeholders  were  compared  and  triangulated  whenever  possible.  Where  available  literature 
was  limited  (e.g.,  linked  to  the  assessment  of  efficiency  and  EU  added  value  criteria)  or 
conflicting (e.g., in particular for data sets), consultation responses were relied upon to answer 
the evaluation questions (and indicated throughout this report where it has been the case). 

More  details  on  how  the  evaluation  was  conducted  are  available  in  Annex  II  (on  the 
methodology)  and in Annex V (the synopsis report, which summarises the results of all the 
consultation activities undertaken for this evaluation) of this report. 

2 

2. 

WHAT WAS THE EXPECTED OUTCOME OF THE DIRECTIVE? 

2.1  2.1. Description of the intervention and its objectives 

The use of sewage sludge in agriculture was not regulated by Directive 75/442/EEC on waste, 
so  it  was  deemed  necessary  to  develop  separate  legislation  on  wastewater  management  and 

6 

 
 
recovery of sewage sludge. The SSD was born from the need to end the discharge of sludge 
into the marine environment. This led to the development of the idea to use sludge on land, 
primarily as  a means of  the disposal  of sludge within  defined safety parameters, but  also  in 
recognition  of  its  agronomic  value.  The  Directive  was  therefore  created  to  encourage  the 
correct use of sewage sludge in agriculture and to regulate its use in order to prevent harmful 
effects on soil, vegetation, animals and humans. This was to ensure diversion of waste from 
disposal  towards  recovery.  To  this  end,  it  prohibited  the  use  of  untreated  sludge  on 
agricultural land unless it is injected or incorporated into the soil.  

The  legal  base  of  the  Sewage  Sludge  Directive  are  Articles  100  and  235  of  the  Treaty 
establishing  the  European  Economic  Community,  relating  to  the  common  (internal)  market. 
The  objectives  pursued  by  the  Directive  are  those  of  facilitating  the  recovery  of  sewage 
sludge  in  agriculture  in  Europe  while  ensuring  that  this  activity  does  not  harm  the 
environment  or  human  health.    This  is  the  primary  objective  identified  on  the  basis  of  its 
article on the purpose of the Directive. Its first recital states that the aim of this Directive is to 
regulate the use of sewage sludge in agriculture in such a way as to prevent harmful effects on 
soil,  vegetation,  animals  and  man,  while  encouraging  its  correct  use.  This  is  in  detail 
explained also in further recitals. Its second recital refers to the disparity between the Member 
States'  provisions  on  the  agricultural  applications  of  sewage  sludge  that  might  affect  the 
functioning of the common market and which therefore justify the introduction of minimum 
harmonisation  at  EU  level.  The  Directive  does  not  provide  for  further  information  on  the 
potential  barriers  to  the  internal  market  that  are  the  subject  of  the  intervention  by  this 
Directive.  However,  it  can  be  assumed  that  this refers  to  unequal  conditions  of  competition 
for the treatment operators of sewage sludge for its recovery and the users of sewage sludge 
as  a  result  of  different  levels  of  regulation  across  the  Union  which  hamper  movements  of 
sewage sludge for recovery in agriculture across the Union. It is also to be noted that Articles 
100 and 235 of the Treaty establishing the European Economic Community were consistently 
used as the legal basis for environmental legislation predating a specific environmental policy 
legal base in the Treaty. 

The Sewage Sludge Directive aims to protect human health and environment by encouraging 
the safe use of sewage sludge in agriculture in order to prevent harmful effects. It does this by 
limiting  heavy  metal  concentrations  in  soils,  by  prohibiting  use  of  untreated  sludge  on 
agricultural land unless it is injected or incorporated into the soil, and by requiring that sludge 
be used in such a way that the nutrient requirements of plants and the quality of the soil and of 
surface and groundwater is not impaired. 

The Directive imposes several requirements on the quality of sludge for use in agriculture, the 
quality of the soil on which sludge is to be used (Article 5) and limiting sludge application for 
certain purposes and during certain time periods (Articles 7 and 8). It also requires that for use 
on farmland, sludge is treated beforehand and account is taken of the nutrient requirements of 
plants. The main aim of these requirements is to limit heavy metal concentrations in soils, and 
to avoid nutrient loss. 

The  Directive  limits  concentrations  of  heavy  metals  in  soils  to  which  sludge  is  applied 
(Article 4, annex IA) by setting: 

-  maximum  concentrations  of  the  sludge  in  6  heavy  metals:  cadmium,  copper,  nickel, 
lead, zinc, and mercury. Limits were also to be set for chromium, but the Directive has 
never been updated with a specific value for that metal;  

7 

 
 
-  maximum concentration of those heavy metals in the soil; 
-  maximum  annual  quantities  of  such  heavy  metals  which  may  be  introduced  into  the 

soil intended for agriculture. 

The Directive requires sludge to be treated before application onto land, therefore throughout 
this report, when referring to “sludge use in agriculture”, it will implictly mean treated sludge 
use  in  agriculture.  The  Directive  does  not  define  treatment,  so  treated  sludge  could  in 
principle  be  product  resulting  from  any  treatment,  e.g.  digestate  from  anaerobic  digestion, 
compost or even incineration ashes. 

The  Directive  covers  application  on  agricultural  land  and  does  not  cover  any  other  uses  or 
disposal routes for sewage sludge. In particular, sludge may also be used on land not intended 
for  agriculture,  for  land  reclamation,  land  remediation,  or  landscaping  which  is  regulated 
under the general rules of the Waste Framework Directive (WFD). 

The Directive implements the overall objective of the Union environmental and waste policy 
to  encourage  the  recovery  and  safe  use  of  waste  in  the  economy  over  its  disposal  where  it 
offers the best environmental outcome. Since sewage sludge contains valuable nutrients such 
as  phosphorus  that  has  beneficial  uses  in  agriculture  as  soil  fertiliser,  this  Directive  aims  to 
regulate  this  use  to  encourage  its  use  while  ensuring  that  it  does  not  undermine  health  and 
environmental protection. 

The main activities required by the Directive to meet its objectives are as follows: 

Article   Target 
group 

5(1) 

Member 
States 

5(2) 

Member 
States 

Description of requirements 

Member  States  must  prohibit  of  use  of  sludge  in  soils  that  exceed  the  limit 
values laid down in Annex 1A; and  
Ensure that those limits are not exceeded as a result of use of sludge. 

Member States must ensure the use of sludge does not lead to an accumulation 
of heavy metals in soil that exceeds the limits in Annex 1A (of the Directive) 
by either: 
Laying  down  the  maximum  quantities  of  sludge  that  can  be  applied  per  area 
per year whilst complying with the limits laid down for sludge in Annex 1 B 
(of the Directive); or 
Ensuring the limits for the quantities of metals introduced into the soil per area 
and unit of time as laid down in Annex 1 C of the Directive. 

6 

7 

Operators 
Member 
States 
Operators 

Sludge must be treated before being used in agriculture.   
Member  States  may  set  their  own  conditions  allowing  untreated  sludge  to  be 
used if it is injected or worked into the soil. 
Sewage  sludge  producers  must  provide  users  of  sewage  sludge  with  the 
information required under Article II A. 

Member 
States 

Member States must prohibit the use of sludge or the supply of sludge for use 
on: 
Grassland  or  forage  cops  if  the  grassland  is  to  be  grazed  or  forage  crops 
harvested before a certain period as defined by the Member State has elapsed. 
Soil in which fruit and vegetable cops are growing except for fruit trees. 
Ground intended for the cultivation of ground contact fruit and vegetable crops 
that are eaten raw for a period of 10 months preceding the harvest of the crops 

8 

 
 
Article   Target 
group 

Description of requirements 

and during the harvest itself. 

8 

9 

10 

Member 
States 
and 
Operator  

Member 
States 
and 
Operator  

Member 
States 

Sludge must be used in a way that the nutrient needs of plants are considered 
and that, the quality of the soil and surface and ground water is protected. 
Where  soil  pH  is  below  6,  Member  States  must  consider  increased  mobility 
and  availability  of  heavy  metals  to  crops  and,  if  necessary,  reduce  the  limit 
values they have defined according to Annex 1 A11. 

Sludge and soil on which it is used must be analysed according to Annexes II 
A and II B.  

Member  States  must  keep  records  of  the  quantities  of  sludge  produced  and 
used in agriculture, the composition, and properties of sludge in relation to the 
parameters  included  in  Annex  II  A,  the  type  of  treatment  carried  out  and  the 
names and addresses of the recipients of sludge and the place where the sludge 
is to be used. 

17 

Member 
States 

Member  States  must  submit  a  report  every  four  years  and  submit  it  to  the 
Commission addressing the quantities of sludge used in agriculture, the criteria 
followed, and any difficulties encountered. 

The  SSD  provides  a  minimum  level  of  harmonisation  on  the  environmental  conditions  to 
ensure  safe  use  of  sewage  sludge  in  agriculture  in  the  EU  as  its  Article  12  specifically 
recognises that Member States may adopt more stringent measures. 

The intervention logic of the Directive is represented on the next page. It shows the intended 
functioning, desired results and overall rationale of the Directive. 

2.2  2.2.  Point(s) of comparison  

The Directive is assessed throughout this report against its expected outputs and impacts, or 
by comparison with the past situation, to the best extent possible since there is a tremendous 
lack of data related to the past.12 To the extent possible, the following scenarios of reference 
points were developed: 

-  Past scenario reflecting the situation at the time the SSD was adopted. 
-  Present scenario (Current Situation). 
-  Present  scenario  WIND  “What  if  no  directive”  -  reflecting  a  hypothetical  present 

scenario whereby the Sewage Sludge Directive would not have been adopted.  

Information on how these scenarios have been developed is provided in Annex III. 

11 Limit values are provided in Annex III of this report 
12 No impact assessment was carried out for the adoption of the Directive. The 2014 evaluation was not based on a baseline 

either. For data rel²ated challenges see section1.3 and Annex II of this report. 

9 

 
 
 
                                                 
The intervention logic can be represented as follows: 

 
 
3 

3. 

HOW HAS THE SITUATION EVOLVED OVER THE EVALUATION PERIOD? 

This  section  presents  the  state  of  play  of  the  implementation,  focusing  on  key  information 
from  the  latest  reporting  period  (2016-201813),  with  additional  information  on  previous 
reporting periods as  appropriate (to the best  extent  possible, since data from  earlier  years is 
very scarce, if not inexistent, as explained in section 1.3).  

All  Member  States  have  fully  transposed  the  Directive  into  national  legislation.  Numerous 
Member  States  have  chosen  to  go  further  than  the  minimal  requirements  set  out  in  the 
Directive, notably by setting lower national limit values for the concentration of heavy metals 
in soil and sludge and setting limit values for additional parameters.  

3.1  3.1. National limit values and requirements at national level 

Member States have set concentration limit values for heavy metals in soil/sludge that are in 
line  with  the  requirements  of  the  Directive.  In  accordance  with  Article  12,  seventeen 
Member States have adopted more stringent requirements than those prescribed in the 
Directive:  Austria,  Belgium,  Croatia,  Czechia,  Denmark,  France,  Finland,  Germany, 
Hungary,  Latvia,  Luxembourg,  Malta,  the  Netherlands,  Poland,  Romania,  Slovenia  and 
Sweden. 

The  stricter  national  rules  adopted  by  some  Member  States  are  significantly  lower  than  the 
limits set out in the SSD. This difference is the greatest for lead. The graph below shows that 
most Member States have adopted limits for lead in soils which are lower than those required 
by the SSD by a factor of 5, even 10. 

EU Member State limit values for the concentration of lead in soils14 

Source: MS implementation reports for the period 2016-2018 

13 More details can be found in  the SSD implementation report 2016-2018. Data for that period are considered reliable, as 

Member States have been exhaustive in their reporting, apart from a few gaps, also described in that report 

14  No  explanations  are  provided  in  the  Directive  on  the  reasons  for  setting  upper  and  lower  limits.  It  is  assumed  that  they 
reflect  the  likely  differences  of  views  of  Member  States  of  the  range  of  acceptable  levels  of  heavy  metals  and 
fluctuations in sludge composition due to changing composition of wastewaters treated and the subsequent treatment.  

11 

 
 
 
                                                 
NB: Portugal is the only country to have set a national limit value above the upper EU limit 
set out in the SSD. This applies to soil with a pH level consistently greater than 7. It is set in 
the form of a derogation in accordance with Annex IA of the Directive, footnote (2). A lower 
limit has been set in Portugal for soil with a lower pH level, which are aligned with the limit 
values set out in the SSD. 

The following graph illustrates the extent to which Member States have adopted stricter limits 
on cadmium in sludge to be applied onto farmland: 

EU Member State limit values for the concentration of cadmium in sludge  

Source: MS implementation reports for the period 2016-2018 

An  exhaustive  set  of  such  graphs  is  available  in  the  Commission  report  on  SSD 
implementation  for  the  period  2016-201815.  That  implementation  report  also  provides  the 
detailed  list  of  limit  values  which  apply  nationally  or  regionally.  In  summary,  for  specific 
parameters regulated, the following can be noted. 

Member States have set limits below or equal to the upper limit set out in the SSD for the soil 
concentration of all the heavy metals which are regulated by the SSD. The only exception are 
Bulgaria,  Portugal  and  Spain  which  have  set  limits  in  exceedance  for  soils  with  a  high  pH 
level, but still in accordance with the flexibility provided by the Directive in specific cases16. 
Countries  having  set  the  most  stringent  upper  limits  are  Denmark  (which  set  lower  limit 
values for all of the heavy metals in soil), and Latvia. The Netherlands and Finland have also 
set stricter limits for copper and mercury respectively.  

All  Member  States  have  reported  limits  within  the  upper  limit  set  out  in  the  SSD  for  the 
concentration of heavy metals in sludge, except Ireland and Sweden, which did not report any 
national  limit  values  for  the  concentration  of  heavy  metals  in  sludge.  Apart  from  Spain, 
Greece, and Cyprus, which have typically set as limits the upper limit set out in the SSD for 
all metals, all Member States have set national limits below this level (most stringent limits by 
Denmark and the Netherlands, except for Copper, for which the most stringent limits were set 
by  Austria,  Finland,  the  Netherlands,  and  Slovenia).  The  limit  values  applicable  in  the 
Netherlands are stricter than those of the SSD across all substances. 

15 EC, Sewage Sludge Directive implementation report 2016-2018    
16 See SSD Annex IA, footnote 2, also available in Annex III of this report 

12 

 
 
 
                                                 
Member  States  have  reported  limit  values  for  the  amount  of  heavy  metals  which  may  be 
added  annually  to  agricultural  land  in  accordance  with  the  limits  set  out  in  the  SSD  for  all 
heavy  metals.  The  most  stringent  limits  have  been  set  by  Finland,  the  Netherlands  and 
Sweden.  A  significant  number  of  Member  States  (Bulgaria,  Cyprus,  Croatia,  Czechia, 
Germany, Denmark, Italy, and Poland) have not reported limits for any heavy metals. 

Many  Member  States  have  also  set  rules  for  additional  pollutants.  The  majority  of 
Member  States  have  set  limit  values  for  chromium  in  soil  and  sludge.  Over  half  of  the 
Member  States  have  included  additional  substances  such  as  additional  heavy  metals  than 
those  regulated  by 
the  SSD,  arsenic,  Polycyclic  aromatic  hydrocarbons  (PAHs), 
Polychlorinated  Biphenyl  (PCBs),  and  absorbable  organic  halogens  (AOX).  Some  Member 
States  have  also  set  limits  on  pathogens  such  as  E.  coli  and  Salmonella,  and  Enterococci17. 
Further 
(Polychlorinated 
dibenzodioxins)/Furans, which are dioxins (7 MS), NP/NPE (3 MS), Lineal Alkyl Sulphate, a 
chemical  commonly  used  in  the  hygiene  and  cosmetics  industry  (2  MS)  and  DEHP  (di(2- 
ethylhexyl) phthalate; 2 MS). 

sludge  considered  by  MS  are:  PCDD 

substances 

in 

Some  Member  States  have  banned  the  use  of  sewage  sludge  in  agriculture,  e.g.  the 
Brussels  and  Flanders  regions  of  Belgium  and  Slovakia  (the  latter  has  established  a  policy 
where  sewage  sludge  is  treated  for  energy  recovery),  the  Netherlands  (since  1995),  some 
regions of Austria (Vienna, Salzbury and Tyrolia). Germany and Austria focus on phosphorus 
recycling from sewage sludge and sewage sludge ash after the incineration of sewage sludge 
through  mono-incineration.  In  Germany,  all  urban  wastewater  treatment  plants  with  over 
50,000 p.e. will have to comply with this requirement from 2032. 

In their implementation reports, Member States are not asked to state reasons why they apply 
stricter limit values or ban the use of sludge in agriculture. 

Only  a  few  countries  have  allowed  to  use  of  untreated  sludge  under  certain  authorized 
conditions  (e.g.  France,  Sweden  and  Estonia).  Some  have  specific  requirements  for 
treatment such as stabilization, heat treatment, composting, or digestion before use (Austria, 
Denmark,  Finland  and  Poland),  thereby  going  beyond  the  requirements  of  the  Directive, 
which is not prescriptive about the type of treatment to be applied. In several countries the use 
of  sludge  in  forests  (Austria,  Belgium,  Germany  and  Netherlands)  and  green  areas  has  also 
been prohibited18. 

Differences in sludge management practices are generally explained by different pedoclimatic 
conditions19.  Other  reason  for  setting  more  stringent  limits  is  the  application  of  the 
precautionary principle, or local situations, e.g. if the baseline content of soil in heavy metals 
is already high. About 10 Member States (e.g. the Netherlands) established their limits based 
on national risk assessment models that consider humans as end points. Other countries adopt 
and eventually adapt limits formulated by other countries. So it can be said that indirectly or 
directly  risk-based  approaches  have  thus  lead  to  stricter  values  in  Member  States.  Other 
reasons  for  setting  stricter  requirements  include  public  perception  or  pursuing  specific 

17 Hudcava et al. 2019 Present restrictions of sewage sludge application in agriculture within the European Union, page 111. 
18 Kelessidis & Stasinakis 2012 
19 Collivignarelli, M., et al., 2019 

13 

 
 
                                                 
objectives  as  regards  sludge  management  (e.g.  a  focus  on  P-recovery  in  Germany  and 
Austria). 

3.2  3.2. Enforcement of the Directive  

The information gathered in the preparation of this report does not indicate any structural or 
systematic issues with infringement of this Directive. Most Member States have established a 
system  of  fines  (ranging  from  €251  to  €100,000)  as  a  means  of  enforcement,  with 
imprisonment also as a means of enforcement in around 30% of Member States. The level of 
fines  depends  on  factors  linked  to  the  use  of  toxic  sludge,  waste  disposal,  non-compliance 
with  record  keeping  or  failure  to  measure  soil  and  sludge  parameters,  sludge  application 
which  exceeds  pollutants  limits  to  soil,  incorrect  use  of  sludge,  failure  to  effectively  treat 
sludge, application of sludge without authorisation, overuse of sludge (which would result in 
its disposal rather than recovery) and environmental damage as set out in national law.  

Between 1994 and 2019, the Commission has pursued three infringement cases in relation to 
the enforcement of the SSD, all of which are solved.20 Overall, this indicates a positive level 
implementation and compliance. 

42% of respondents during the targeted consultation reported that the enforcement of the SSD 
in their country has been fully effective, followed by 27% respondents indicating that it has 
been  effective  to  some  extent.  Around  43%  of  those  participating  in  the  Member  State 
consultation  (of  19)  indicated  that  enforcement  of  the  SSD  had  been  fully  effective  in  their 
country, while 21% reported that enforcement had been to a large extent effective and 37% to 
some extent. No respondents reported that it had not at all been effective. 

3.3  3.3. Sludge production and use  

Depending  on  the  source  of  data  considered,  sludge  use  in  agriculture  across  the  EU  falls 
between about 30 and 50% of the total amount of sludge produced. By triangulating data, it 
can be estimated to be an average of around 40%. As can be seen from the figure below, the 
amount  of  sludge  produced  has  remained  relatively  stable  between  2007  and  2018,  with 
production  typically  averaging  between  7M  –  8M  tonnes21.  The  amount  of  sludge  used  in 
agriculture has also remained constant, between 2M – 3M tonnes.  

The fluctuations observed for the production of sludge could not be explained but by resulting 
from data gaps (see Annex II for details on data scarcity). It can be noted, however, that the 
percentage of sludge used in agriculture follows the pattern of sludge produced. This has been 
observed  for  evolutions  examined  from  the  three  main  data  sources  used:  Member  State 
implementation reports (submitted as a requirement of the Directive), Eurostat, and Member 
State overviews (files developed for each MS) prepared in the framework of the study which 
supported this evaluation22. 

20 BE in 1994 (on failure in  implementation), AT in 2003 (on failure in transposition and implementation), IT in 2004 (on 

failure to meet reporting requirements and record keeping) 
21 About 17 kg per person per year [from Anderson et al, (2021)] 
22 A graph is also provided in Annex III to show trends on the long run (1980-2018) for the EU27 according to Eurostat data. 

14 

 
 
                                                 
Sludge produced and used in agriculture in the EU 2007-2018 

Source: MS reporting on the implementation of the SSD, complemented with extrapolation where information is missing for that period 
(see Annex II for details on how the extrapolation was made). The graph has been drawn from 2007 onwards, due to the extreme scarcity 
of data from earlier years. Note that even after 2007 data sets remain very incomplete, as described in Annex II. The most notable yearly 
change occurred between 2012–2013, when there was a sharp decrease. The decrease is a reflection of reduced total sludge production 
reported  in  Spain,  Finland  and  Portugal.  There  was  no  information  identified  to  explain  these  decreases  in  these  countries.  A  further 
decrease is observed between 2017-2018 reflecting decrease in quantities reported by Bulgaria and Italy. 

Present-day,  the  majority  (24)  of  Member  States  use  sewage  sludge  in  agriculture  (see  also 
section 2.1). Most of them use less than 40% of their sludge in this way, for an EU average of 
31%. These shares vary a lot between them, from very high use (e.g. Ireland) to low or no use 
in agriculture (e.g. Belgium, Malta, Slovakia and Slovenia).  

The evolution and trend differs very significantly between Member States. When comparing 
sludge  use  in  agriculture  in  2010  and  2017/2018,  for  instance,  we  note  an  increase  for  a 
majority of Member States, while some report a decrease (see figure below), sometimes very 
significant in both cases. 

15 

 
 
 
 
Share of sewage sludge used in agriculture (as % of total sludge produced) 

Source: Member State Implementation Reports  

Note: The figures for Austria, Belgium and Italy are  representative of the regions  which provided information for the relevant 
years. Slovenia provided data suggesting a very small %  use of sludge in agriculture which is not visible within the chart. The 
chart  does  not  reflect  data  for  Member  States  that  did  not  provide  information  for  either  the  year  2010  or  2017/2018.  This 
applies to Malta and Latvia for both years. France and Denmark did not provide an implementation report for 2010-2012 but 
according  to  Eurostat  data,  France  produced  1.025kt  of  sludge  in  2010  and  used  41%  of  it  in  agriculture,  while  Denmark 
produced 141kt of sludge and used 52% of it in agriculture for that year.  

3.4  3.4. Different types of treatment and uses of sludge 

Sewage sludge requires  treatment  before application  onto  land, to enable safe use and more 
efficient  transport,  for  recovery  (of nutrients  or  energy)  and/or disposal.  Common treatment 
options  include  thickening,  stabilisation,  dehydration  and  sometimes  drying  of  sludge. 
Additional techniques include lime treatment, anaerobic digestion (process in which bacteria 
biodegrade organic materials in the absence of oxygen), or composting. An overview of the 
main types of treatment used, their main features and effects they have is provided in Annex 
III to this report. 

Sludge  dewatering  in  treatment  significantly  reduces  the  water  content  of  the  sludge,  and 
therefore  the  volume  and  weight  of  wet  sludge  for  disposal.  Methods  based  on  physical, 
mechanical,  chemical,  thermal  and  biological  treatments  are  used  to  further  decrease  the 
volume  of  sludge.  Most  of  them  are  aimed  at  solids  solubilisation,  virus  inactivation,  and 
disintegration of bacterial cells in sludge. 

After treatment (usually a combination of different steps of treatments), sludge can be used or 
disposed of in different ways: recovery through spreading on farmland, energy recovery from 
incineration or landfilling. Sludge can also be recovered through application on soil other than 
agricultural  soil  as  a  soil  improver,  for  landscaping  or  land  reclamation.  Some  treatments, 
while  treating  sludge  for  its  subsequent  application  on  land,  also  pursue  other  objectives, 

16 

 
 
 
namely:  anaerobic  digestion  generates  methane  (in  the  form  of  biogas),  which  can  then  be 
used as (bio)fuel. Apart from incineration, such treatment options are usually taking place at 
the  urban  wastewater  treatment  plants  (WWTP)  that  generate  sludge,  and  can  be  used 
independently  of  the  intended  end  use  of  the  sludge.  WWTPs  may  be  the  end-users 
themselves of the biogas or energy production in view of their high energy demand to process 
wastewaters.  

Land use application has remained the main route for managing sludge in the EU as a whole, 
as shown by the below diagram. Incineration comes closely second. 

Eurostat data on the production and disposal of sewage sludge in the EU-28, 2004-2016 

Source: Eurostat, 2016. Sewage sludge production and disposal [ENV_WW_SPD]. 

NB: Eurostat does not provide a description of the category ‘other’. This is one of the factors that 
impacted data collection and comparison with other sources (the categories differ) for this evaluation, 
as described in Annex II. 

However, as can be seen on the next figure, large differences in the proportional contribution 
of  sewage  sludge  disposal  routes  exist  among  Member  States  for  the  final  uses  of  sewage 
sludge. Some countries incinerate high proportions of their sewage sludge (e.g. Netherlands, 
Belgium, Germany; 82-98%), others (e.g.  Ireland, Spain; >80%) apply large amounts of the 
sewage sludge directly on land, and some landfill significant amounts of sludge (e.g. Greece, 
Italy, Romania, and Croatia; 28-86%).  

17 

 
 
 
Relative importance of sludge management options within different EU Member States  

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Source:  Eurostat  2016  data.  Data  gap  filling  performed  for  some  Member  States 
based on 2010 – 2015 data. 

3.5  3.5. Metal concentrations in sludge used in agriculture and in soils 

where it is used 

The EU-average levels of the presence of the heavy metals regulated by the SSD in sludge all 
remained significantly below the limits set in  the SSD over 2007-2018, very often 10 times 
lower. Examples are provided below for Cadmium, and Lead (average for EU-27, data taken 
from MS implementation reports), for which most significant decrease has been observed: 

Overall for the whole EU the concentrations of lead and cadmium in sludge  have decreased 
between 2007–2018, respectively by 54% and 18%. The levels of nickel, chromium, copper 
and zinc have remained rather stable. The mercury content has overall decreased too (by more 
than 30%), though showing the sharpest fluctuations over the period. Details on the evolution 
of  these  concentrations  can  be  found  in  the  2016-2018  SSD  implementation  report  (still 
bearing in mind the noted gaps in reporting). 

There are no data as regards the concentration of heavy metals in soils where sludge has been 
used since this is not linked to a reporting requirement in the Directive. 

18 

 
 
 
 
 
4 

4. 

EVALUATION FINDINGS 

4.1  4.1. To what extent was the Directive successful and why?  

2.1.1. 

4.1.1. Effectiveness 

2.1.1.1.  Assessment of the success of the Directive in reaching its objectives 

It has to be noted that the purpose of the Directive is not to impose sludge use in agriculture, 
but rather to encourage this practice where it is safe to the environment, to human health and 
has benefits  to  the  circular economy through the  recovery of nutrients.  The effectiveness  of 
the Directive is assessed against its objective, as stated in its Article 1, which is to facilitate 
the use of sewage sludge in  agriculture in  such a way  as to  prevent  harmful effects  on soil, 
vegetation, animals and man, thereby encouraging the correct use of such sewage sludge. In 
this context, “correct” means that: 

1.  the limits set for the following parameters are respected: 
concentration of certain heavy metals in soil, 
concentration of certain heavy metals in sludge,  
annual quantities of certain heavy metals which may be introduced into soil intended 
for agriculture, 

- 
- 
- 

2.  and plant needs are respected as well as other restrictions on the application of sludge in 

certain times or areas. 

The  Directive  has  been  effective  in  establishing  a  minimum  level  of  harmonisation  for 
environmentally safe recovery of sewage sludge through use in agriculture.  It has also been, 
so  far,  the  only  legislation  with  soil  protection  as  its  primary  objective.  All  Member  States 
have set and applied limits for the parameters regulated by the SSD, ensuring monitoring of 
heavy metal content in sewage sludge and in agricultural land where sewage sludge is to be 
used.  

The Directive does not require soil quality data to be reported (separately or in conjunction to 
the sludge used)  to  the  Commission.  There are  also  no other  EU level  data to  correlate soil 
quality and the use of sewage sludge. Data are rather available on the quality of sludge, or on 
the quality of soil, but not specifying whether sludge has been applied onto them, or looking 
across all other sources of pollutions, not allowing to single out the contribution of sludge23. 
Some  examples  of  review  of  soil  quality  in  Lombardy  and  through  a  review  of  samples 
collected as part of the LUCAS24 top soil survey found regional differences in the percentage 
of  heavy  metal  concentration  above  the  SSD  threshold  value,  and  also  some  comparison  in 
some  instances  between  soils  where  sewage  sludge  had  been  used  or  not.  Beyond  these 
specific  examples,  there  are  no  EU-wide  or  country-level  data  identified  to  correlate  soil 
quality and use of sewage sludge in a systematic way. It is as such, not possible to assess to 
what extent the Directive has safeguarded agricultural soils from pollution as a result of use of 
sewage sludge at EU level.   

23 Chengfeng, L et al, 2019 
24 Land Use and Coverage Area frame Survey, gathering information on land cover and land use across all Member States: 

https://esdac.jrc.ec.europa.eu/projects/lucas 

19 

 
 
                                                 
There  are  large  variations  between  the  Member  States  in  the  extent  of  sludge  use  in 
agriculture with some Member States directing the majority of sludge to this use while others 
restricting this use considerably. But overall, sludge has been widely and steadily used to the 
benefit of agriculture, leading to the recovery of nutrients from 2 to 3 million tons of sludge 
per year in the EU.25 However, this has contributed to improving the agronomic properties of 
soils and to avoiding the disposal of sewage sludge through landfilling. In the absence of the 
Directive  setting  quantitative  objectives  for  sludge  use  or  nutrient  recovery  and  in  view  of 
other  competing  forms  of  soil  improvers  and  sewage  use,  the  reported  use  of  sludge 
demonstrates  that  the  Directive’s  objectives  to  encourage  safe  use  of  sludge  in  agriculture 
have been met. 

Between 2007 and 2018, the concentration of heavy metals in sludge has steadily decreased, 
to levels below the limits set by the Directive. However, it is difficult to determine to which 
extent  this  is  owing  to  its effects,  or to the more stringent limits applying in some  Member 
States, to environmental protection policies and legislation and the gradual reduction in metal 
emissions from effluents entering urban wastewater treatment plants from industrial facilities. 
The OPC results suggest that the SSD has been effective in improving the quality of sewage 
sludge  used  in  agriculture:  54%  of  respondents  (94  of  173)  reported  improvements  which 
would not have occurred to an identical level if the SSD did not exist. Respondents identified 
as farmers were split on this question, with 9 answering positively on the role of the SSD, and 
10 answering negatively26. 

Respondents to the open public consultation were divided on the extent to which the changes 
in amounts of sewage sludge use and the safety of its use in their country of residence can be 
attributed to the SSD. Nevertheless, 79% (n=122 out of 155) agreed that it had at least played 
a role to some extent. 53% saw other (sub-)national laws as partly or fully responsible for the 
changes  observed.  Finally,  74%  believed  that  other  non-regulatory  factors  were  at  least  to 
some extent responsible for the changes observed. 

The Member States targeted consultation asked to what extent they agreed that the SSD had 
led to changes or results in their country (in general). Overall, responses suggest that the SSD 
has  had  a  neutral  to  positive  impact  on  changes  or  results,  such  as  a  generally  sustainable 
framework for the use of sewage sludge in agriculture, increased safe use of sewage sludge in 
agriculture, with minimisation of pollution and health risks, increased nutrient recycling and 
carbon  sequestration,  and  an  improvement  in  the  quality  of  agricultural  soils  in  their 
country/region. Targeted stakeholders generally agree that overall, such changes or results had 
occurred  because  of  the  SSD27.However,  an  analysis  made  by  Wood28  based  on  qualitative 
criteria such as evolution of sludge use in agriculture in the Member States and whether they 
have set more stringent requirements for that use than those of the SSD, would indicate that, 
at least in recent  years, the implementation of the SSD has influenced or still influences the 

25  If  the  sludge  or  soil  content  exceeds  the  set  limit  values,  a  decrease  of  that  use  should  occur,  since  the  use  would  not 

otherwise be “correct”. 

26  28%  answered  that  there  would  have  been  no  noteworthy  improvements  without  EU  legislation.  For  26%,  levels  of 
appropriate sludge use would have improved without the SSD but would be lower than today”. 12% believed that other 
regulations  in  place  before  the  SSD  explain  the  improvements  observed;  12%  did  not  believe  that  sludge  quality  has 
increased; 12% did not know, 10% thought that improvements made up until now would have happened anyway”. 
27  Listed  in  the  questionnaire  as  ‘Led  to  minimisation  of  pollution  and  health  risks  from  sewage  sludge  use’;  ‘Led  to 
increased phosphorus and nutrient recycling and carbon sequestration’; ‘Led to increased safe use of sewage sludge in 
agriculture’; and ‘Led to a generally sustainable framework for the use of sewage sludge in agriculture’ 

28 details are also provided in Annex III, EQ1 

20 

 
 
                                                 
management  practices  of  sewage  sludge  only  to  a  limited  extent  (only  in  about  half  of 
Member States, according to the analysis, but this figure is to be taken very cautiously).  

In accordance with Article 12 of the Directive, 17 Member States have adopted stricter limit 
values for the heavy metals than the SSD, some also regulating additional substances. These 
developments  certainly  contribute  to  the  objectives  pursued  by  the  Directive  beyond  the 
requirements  of  the  Directive.  However,  they  may  also  be  regarded  as  putting  in  question 
whether the parameters which it regulates and the limits which it sets still provide a minimum 
level protection that ensures high level of protection of the human health and the environment. 
It also makes it challenging to distinguish the effects of the SSD itself from national action. 

4.1.1.2.      Other effects of the Directive 

Sludge not only enhances fertility of soils through its organic and nutrient content, but it can 
also foster soil structure and carbon concentration29. Lime-treated sludge can also help reduce 
the acidity of agricultural soils. During the OPC, over half of respondents reported measurable 
improvement  in  the  quality  of  agricultural  soils  from  the  use  of  sludge.30  Results  of  the 
consultation of Member States show a split in the opinion on the question (29% of 14 agreed 
to that, 29% disagreed and 43% were neutral).  

Another positive effect noted for the Directive is an increased interest in sewage sludge, and 
the  increased  knowledge  related  to  sewage  sludge  including  the  large  number  of  research 
projects considering sewage sludge. 

Sludge  application  can  also  present  negative  unintended  externalities.  The  long-term 
application of sewage sludge could cause an increase in the antibiotic resistance of bacterial 
communities31, although study conducted in Sweden concludes the opposite32 . Sludge use in 
agriculture also  generates emissions to air and water, as described below. It has to be noted 
that other sludge management routes can generate such emissions too19. 

Other  types  of  pollution  should  be  considered  too,  for  areas  where  the  effectiveness  of  the 
Directive  could  not  be  assessed  with  certainty,  notably  as  regards  the  list  of  contaminants 
covered by the Directive. A study conducted by the JRC on the basis of modelling found that 
a relatively small set of organic pollutants may cause significant risks to both humans and soil 
organisms following  landspreading33. Another study shows that  around 1% of the weight  of 
sewage sludge is made up of microplastics.34 

The treatment of sewage sludge in WWTP (which is needed as conditioning for use of sludge 
on land) has been linked to increased methane emissions, mainly from the treatment of sludge 
by anaerobic digestion (and, mainly, leaks from these equipment facilities) account for about 

29 Börjesson and Kätterer, 2018 
30 Of 171 respondents, 55% reported a positive or very positive effect on soils and 13% reported a very positive effect, 23% 
reported a negative or very negative effect, 15% reported neither negative nor positive, and 8% ticked the box of ’did 
not know’.  

31 Qinglin, C., Xinli, A., Hu, L., Jianqiang, S., Yibing, M., & Yong-Guan, Z. 2016. Long-term field application of sewage 
sludge increases the abundance of antibiotic resistance genes in soil. Environment International, 92-93, 1-10.  
32 Rutgersson C. et al, 2019 
33 Huygens et al., 2022 
34 Microplastics removal from a primary settler tank in a wastewater treatment plant and estimations of contamination onto 
  Environmental  Pollution,  Volume  304,  2022. 

European  agricultural 
https://www.sciencedirect.com/science/article/pii/S0269749122004122#aep-article-footnote-id8 

land  via  sewage  sludge  recycling, 

21 

 
 
                                                 
three  quarters  of  WWTPs  overall  methane  emissions.  These  methane  emissions  can  have  a 
larger greenhouse gas footprint than the carbon dioxide emissions that are avoided by using 
the  resulting  biogas  for  energy  generation35.  However,  not  all  anaerobic  digestion  processes 
are followed by sludge use in agriculture, so these emissions are not specifically linked to the 
SSD. 

Application of sludge on land can also generate emissions of nitrous oxide (N2O, a gas with 
very high  greenhouse potential) and ammonia,  as investigated by Milieu  et  al.  (2010).36 For 
sludge to be applied on land, there may also be exhaust emissions (of ozone depleting gases 
and CO2) due to transportation36. Air emissions and water pollution can also result from the 
over-application of sludge, if it is applied in excess of plant needs. The extent to which this 
happens  is  not  known,  as  no  specific  examples  of  MS  considering  the  plant  needs  before 
sewage sludge is applied were identified (and this is not information which they are required 
to report on). 

4.1.1.3.      External factors of influence on sludge use in agriculture 

  Factors having positively influenced the achievement of the objectives of the SSD 

79%  of  155  OPC  respondents  agreed  that  the  possibility  for  Member  States  to  set  more 
stringent requirements had played a role in the effectiveness of the SSD. Over half (53% of 
156)  of  respondents  agreed  that  other  (sub-)national  laws  were  to  a  large  extent  or  fully 
responsible  for  the  changes  observed  in  their  country  of  residence,  as  a  result  of  more 
stringent  measures  put  in  place  by  some  Member  States.  In  the  targeted  consultations  with 
Member States and stakeholders, most strongly agreed or agreed that stricter limit values of 
one  or  more  heavy  metals  concentrations  in  sewage  sludge  set  by  Member  States  had 
contributed to the achievement of SSD objectives. 

Sludge  production  has  increased  considerably  since  the  adoption  of  the  Directive,  and  its 
quality has improved over time in terms of content of heavy metals legislated by the SSD37, 
which is  considered  a positively influential  factor.  The evolution  of sludge use on farmland 
follows  that  of  sludge  production,  reflecting  the  need  to  dispose  of  sludge  produced  (see 
figure  on  sludge  production  and  use  in  section  3.2).  There  have  been  some  significant 
technological  improvements,  for  example,  improvements  in  wastewater  purification  and 
sludge treatment technologies and plants, that have been developed to meet the requirements 
of the Directive. The resulting improvements in sewage sludge quality have also had positive 
knock-on  impacts  for  effluent,  wastewater  and  water  quality,  bringing  wider  benefits  than 
simply improvements for sludge used in agriculture. 

Quite a few voluntary schemes have been put in place in a number of Member States. Under 
these systems, sewage sludge producers provide recipients with a certificate which guarantees 
that sewage sludge meets specific quality standards. This further improves the confidence of 
farmers  relying  on  it  as  fertiliser,  thereby  supporting  the  use  of  sludge  in  agriculture. 

35 Daelman, M et al. 
36 Milieu et al., (2010) Environmental, economic, and social impacts of the use of sewage sludge on land 
37 See section on legislation preventing pollution at the source in section 4.1.3 on coherence. Also, emissions of heavy metals 
across  Europe  decreased  since  1990  in  alignment  the  EU  commitments  under  the  UNECE  Air  Convention.  Between 
2005  and  2019,  emissions  have  continued  to  decline,  with  lead  emissions  decreasing  by  44%,  mercury  emissions  by 
45% and cadmium emissions by 33% across the EU-27 Member States (EEA, 2021) 

37 European Commission workshop. (n.d.): Technology and innovative options related to sludge management.  

22 

 
 
                                                 
Examples  include  Ireland,  alongside  its  Code  of  Good  Practice  for  Use  of  Biosolids  in 
Agriculture38,  Sweden’s  REVAQ  certification  system39  and  France’s  RISPO  Certification, 
which  provides  a  guarantee  that  sewage  sludge  has  ‘agronomic  interest’,  meeting 
environmental,  health  and  safety  requirements  and  which  includes  an  audit  of  WWTP  and 
agricultural operators40.  

Other  legislation  of  the  waste  acquis  also  facilitate  the  recovery  of  sludge.  The  landfilling 
Directive  (1999/31/EC),  which  aims  at  reducing  the  amount  of  waste  which  is  landfilled, 
made landfilling of sludge decrease considerably over the past years, partly to the benefit of 
sludge  use  in  agriculture.  The  Waste  Framework  Directive  (2008/98/EC)  sets  a  waste 
hierarchy  requiring  to  prioritise  nutrient  recovery  over  energy  recovery  or  disposal.  As 
foreseen by that Directive, some Member States have adopted national ‘end-of-waste’ criteria 
which recognise the status of digestate (the material remaining after the anaerobic digestion) 
and/or of compost as products and no longer waste. This facilitates sludge use in agriculture 
and improves public trust in the product. However, such criteria differ among Member States 
and stakeholders indicate that a lack of a broader set of criteria and a harmonisation of end-of-
waste criteria are  a barrier for  (more innovative,  e.g.  production of bioplastics from  sewage 
sludge)  sludge  processing  technologies  and  applications  that  aim  at  making  products  form 
sewage  sludge,  including  for  other  than  agriculture  uses41.  The  status  of  sludge  as  waste 
furthermore influences  its treatment  and uses in  view of compliance and transportation  cost 
implications  for  its  shipments  as  waste.  Acquisition  of  a  non-waste  status  is  also  a  factor 
influencing  technological  developments  in  view  of  the  increasing  priority  to  tackle 
phosphorus depletion and EU’s dependency on imported phosphate fertilisers. The SSD does 
not regulate the end-of-waste status of sewage sludge; it only regulates the conditions for its 
application  on  agricultural  soil.  The  Fertilising  Product  Regulation  2019/1009  establishes 
end-of-waste  criteria  for  EU  fertilising  products  containing  certain  materials  derived  from 
sewage sludge.  

As will be seen in section 3.1.2 on efficiency, the cost of sludge application is lower than tht 
of other sludge management options, provided that  distances  from  suitable agricultural  land 
are not prohibitive. When sludge must be transported, costs can become too high for a cost-
effective use of sludge in agriculture, thus leading to less availability for reuse. The European 
Court of Auditors noted that there were significant variations among WWTPs reviewed in the 
cost  of  transport  and  disposal  of  sludge.  The  share  that  costs  of  transport  and  disposal  of 
sewage sludge can represent in the total operation costs of the WWTP also varies, with up to 
50% of the total operating costs of the WWTP, in some extreme cases42. 

  Factors having negatively influenced the use of sludge in agriculture 

Sludge  use  in  agriculture  has  typically  competed  with  incineration  and  landfilling. 
Additionally,  this  use  is  not  possible  at  certain  periods  of  the  year,  e.g.  winter,  or  during 
periods  of  plant  growth,  when  the  plant  nutrient  demands  are  low.  This  requires  storage 

38  Aqua  Publica  Europea.  (2019).  Thematic  Workshop:  Towards  a  sustainable  approach  to  sludge  management:  legal 

frameworks and technological solutions  

39 EEA, n.d. Provision of services in the area of sewage sludge and the circular economy (upcoming) 
40 RISPO. (n.d.) https://rispo.org/certifications  
41 Aqua Publica Europea. (2019). Thematic Workshop: Towards a sustainable approach to sludge management: legal 
frameworks and technological solutions  
42 European Court of Auditors, 2015 

23 

 
 
                                                 
facilities during these periods and increases its management costs, therefore pointing in favour 
of other treatment routes for sludge. 

Feedback  from  stakeholders  noted  the  increased  interest  in  using  sewage  sludge  as  fuel  for 
industrial processes. It was also noted that being a biomaterial, for industries regulated under 
the  Emissions  Trading  Scheme,  using  sewage  sludge  to  produce  energy  allows  to  reduce 
emissions allowances needed. Sludge is considered to be more environmentally friendly than 
coal, so there are therefore less allowances to provide for the use of it, and this also provides 
an  incentive  for  incineration  (typically  in  the  cement  industry  in  this  case).  This  sludge 
management  route  may  become  more  prominent  in  view  of  the  Union  policies  on  energy 
independence and climate neutrality. Mono-incineration can also be a first processing step to 
recover phosphorus in a form that resembles the phosphorus density of phosphate rock, to be 
used  in  fertilising  products  or  other  applications  for  the  phosphate  industry.  Therefore  this 
sludge  management  route  has  the  potential  to  help  reduce  dependency  to  imports  of 
phosphorus which has been declared an EU critical raw material.  

Many  other  types  of  sludge  can  be  generated  from  industrial  processing  of  animals,  milk 
processing, or paper mills (paper sludge), or from manure in livestock rearing activities43. The 
use of these sludges in agricultural soil can be less tightly regulated as they contain a narrower 
spectrum of contaminants. Manure also further competes with sludge as it is commonly used 
in agriculture in large quantities.   

Sludge also competes with bio-waste, which may be of better quality as it generally contains 
less  contaminants,  whether  chemical  or  physical  (plastics,  micro-plastics)  or  biological 
(pathogens)44. As of 2024, when Member States are required to introduce separate collection 
of biowaste under Article 22 of the Waste Framework Directive, more bio-waste as compost 
will be available for use in agriculture and competing with the sewage sludge. 

  Other relevant factors 

Public  and  farmers  confidence  in  sludge  use  is  mixed  across  the  EU45  46  47,  notably  due  to  a 
lack of confidence in its safety or odour nuisances, resulting in a lower acceptance of sludge 
by  farmers48.  There  is  lack  of  understanding  on  the  safety  of  sludge  use,  which  may  even 
result  in  resistance  from  food  retailers  or  consumers’  approach  to  crops  grown  on  soil 
fertilised  with  sewage  sludge.49  Stakeholders  have  indicated  that  improved  fact-based 
communication on the safety and benefits of sludge use in agriculture would be beneficial to 
raise  confidence  in  such  applications.50  Research  undertaken  to  find  a  link  between  strict 
requirements  and  public  trust  provides  mixed  results.51  The  lack  of  public  acceptance  can 
affect  policy  decisions:  a  link  has  been  identified  between  the  negative  attitude  of  the 
population on the agricultural use of biosolids (e.g. France and Germany) and Member States 

43 European Commission. (n.d.). Technology and innovative options related to sludge management.  
44 Milieu Ltd; WRc; RPA. (2010). Environmental, economic, and social impacts of the use of sewage sludge on land  
45 Aqua Publica Europea. (2019). Thematic Workshop: Towards a sustainable approach to sludge management: legal 

frameworks and technological solutions  

46 European Commission workshop (n.d.): Technology and innovative options related to sludge management.  
47 https://www.italianostra.org/wp-content/uploads/DOCUMENTO-FANGHI-DA-IMPIANTI-DI-DEPURAZIONE.pdf  
48 European Commission. (2001). Disposal and Recycling Routes for Sewage Sludge Part 1—Sludge Use Acceptance Report 
49 European Commission. (n.d.). Workshop: Technology and innovative options related to sludge management.  
50  Aqua  Publica  Europea  (2019).  Thematic  Workshop:  Towards  a  sustainable  approach  to  sludge  management:  legal 

frameworks and technological solutions. 

51 Collivignarelli, M., et al. (2019) 

24 

 
 
                                                 
setting stricter requirements on limit values than the SSD. For those Member States with limit 
values  similar  to  the  SSD  the  public  perception  varies.  In  most  cases  (e.g.  Ireland,  Italy, 
Portugal, Spain), no debate was identified in the general public.52 

Expert  respondents  in  the  OPC  indicated  that  the  perception  by  stakeholders  and  the  public 
was still one of the most hindering factors of the use of sludge in agriculture. Results from the 
targeted consultation include 77% of respondents (30 of 39) agreeing or strongly agreeing that 
the negative perception of sludge by the food industry due to potentially contaminated soils or 
agricultural  products  hampers  the  achievement  of  the  SSD’s  objectives.  A  slightly  lower 
percentage (although still the majority) reported that the negative perception by the public was 
also a negative factor (62% of 39). Perceptions of sludge use by stakeholders and the general 
public  hindered  the  achievements  of  the  SSD’s  objective  were  reported  by  32%  of  OPC 
respondents  (48  of  152)52.  A  similar  proportion  of  respondents,  however,  considered  this 
factor to have facilitated the achievements of the SSD’s objectives (31%: 47 responses) 53.  

Local conditions54 have a strong impact on sludge management and use. Geographical drivers 
that  affect  the  sewage  sludge  management  route  include  the  local  influent  composition  of 
wastewater (e.g. caused  by variations  in  rainfall, local  industry etc. which can  affect  sludge 
composition),  the  local  climate,  soil  quality  and  nutrient  needs,  the  availability  of  treatment 
infrastructure, the proximity of the sites for further use of sludge to the WWTP (as this has a 
major  impact  on  the  cost  of  using  sludge  on  farmland),  seasonality  and  location-specific 
legislation.  For  the  use  of  sewage  sludge  in  agriculture  the  most  common  drivers  include 
specific benefits to soil health such as its ability to increase soil organic matter and the high 
energy demand of drying and alternative disposal routes. However, these benefits are opposed 
by  the  risks  associated  with  contaminants  found  in  sewage  sludge,  the  costs  of  transporting 
sewage  sludge  from  WWTPs  to  the  rural  sites  of  disposal  and  the  relative  benefits  of 
alternative technologies such as incineration and pyrolysis (thermal degradation at very high 
temperatures and in the absence of oxygen). 

2.1.2. 

4.1.2. Efficiency 

2.1.2.1.     Costs and benefits arising from the implementation of the Directive 

  Direct costs 

The main direct costs associated with sludge use in agriculture relate to: 

1.  The treatment(s) of sludge before its use 

Sludge  is  treated  in  various  ways  at  a  WWTP,  e.g.  chemical  and/or  biological 
stabilisation,  dewatering, drying. Anaerobic digestion  for example has the advantages of 
simultaneously  recovering  energy  to  operate  the  WWTP  itself,  reducing  sludge  volume 
(which  lowers  transporting  cost),  improves  dewatering  and  stabilises  or  hygienises  the 
sludge for agricultural use. 
At present, sludge is subjected to anaerobic digestion at around 2 200 UWWTPs55. Around 
10% of the EU UWWTPs>2 000 p.e. use anaerobic digestion for sludge treatment. 

52 10% reported this factor had ‘greatly and 22% reported it had ‘hindered’, 
53 7% reported the factor had ‘greatly facilitated’, and 24% reported ‘facilitated’.  
54 Wood, exploratory study (2022) 
55 EBA (2021) Statistical report 2021. European Biogas association. 

25 

 
 
                                                 
These  treatment  processes  involve  investments  into  infrastructure,  and  operating  costs, 
including  labour  costs.  Such  costs  are  usually  borne  by  the  wastewater  treatment  plant 
operators,  depending  on  the  structure  of  the  water  and  sanitation  sector  in  the  region 
concerned.  Wastewater  treatment  plant  operators  are  either  private  companies  operating 
for  a  public  competent  authority,  public  companies  owned  by  the  public  competent 
authorities  (around  60%)  or  mixed  companies56.  The  cost  for  sludge  treatment  at  the 
treatment  plant  are  not  included  in  the  sludge  disposal  costs  for  the  different  sludge 
management options.  It was deliberately decided not to agglomerate the costs for sludge 
treatment at  a WWTP and the subsequent  costs for the use, treatment and/or disposal of 
the  sludge.  An  essential  reason  is  that  the  costs  and  also  the  economic  benefit  of 
individual treatment steps such as sludge digestion at the WWTP cannot always be clearly 
allocated to the treatment plant or subsequent disposal of the sludge. In addition, the costs 
for  sludge  treatment  at  a  WWTP  are  already  subject  to  very  large  uncertainties,  which 
depend above all on the size of the WWTP. Aggregation of the costs would not allow a 
clear interpretation of the costs for individual sludge management options.  

2.  The  transport  of  the  sludge,from  where  the  sludge  is  generated  or  treated  to  the 

destination farmland 

3.  Storage of the sludge, possibly,  in (fall/winter) periods when it is not permitted to spread 

organic materials. 

4.  Application (spreading) onto the agricultural field. 

The following tables provide examples of such costs, occurring at the WWTP or associated to 
final use, treatment or disposal. Data scarcity was compensated through information gathered 
through the targeted stakeholder consultation. More detailed cost data are presented in Table 2 
in Annex III. 

Sludge treatment at the WWTP   Cost range, €/t DM 

Year 

Country 

Source 

Anaerobic digestion  

(20-50)-200 
130-5101 

- 

Stakeholder consultation;  
Egle et al., 2023 (under 
development)57 

Mechanical dewatering 

75-2-300 

2016 

Germany 

INECTUS, 2016 ; JRC data ; 

Solar drying 

125-360 

2018 

Germany 

Egle et al., 2023 (under 
development) ; 
Kabbe et al., 2018 

Thermal drying 

150-715 

2015, 2016 
2018 

Italy, 
Slovenia, 
Germany 

Diaz, Gracia and Canziani, 
2015; Bratina et al., 2016; 
Stakeholder consultation; 
Egle et al., 2023 (under 

56 SWD(2022) 541 final 
57 Egle et al., 2023 (under development) 

26 

 
 
 
 
 
 
                                                 
 
 
 
 
 
 
 
 
development); Kabbel et al., 
2018 

Sludge management option 
agriculture 

Cost range, €/t DM 

Year 

Country 

Source 

Agricultural use  
(wet sludge) 

Agricultural use  
(dewatered sludge) 

100-375 

2018, 2021 

80-175 

2018, 2021 

Germany,  
Austria 

Kabbel et al., 2018 ;  
Amann et al. 2021 

Germany, 
Austria 

Kabbel et al., 2018 ;  
Amann et al. 2021 

Transport 

Cost range, €/t DM 

Year 

Country 

Source 

Transport with truck (15 km3, 
30 t capacity) 

3-4 (dewatered sludge) 

  Transport with tractor 
and trailer (15 km3, 14 
t capacity) 

60-70 (wet sludge) 
8-10 (dewatered 
sludge) 

Egle et al., 2023 (under 
development) 

Egle et al., 2023 (under 
development) 
Egle et al., 2023 (under 
development) 

1 An economic operation becomes feasible for WWTP exceeding 20 000-30 000 p.e. 
2 Cost for WWTP with capacities from 20 000 to 500 000 p.e (population equivalent) (for small WWTP anaerobic digestion 
is very expensive.  
3 Typical transport distance for direct sewage sludge use (Amann et al., 2021) 

5.  Other costs borne by the treatment plants, competent authorities and farmers arising from 
the implementation of the Directive, depending on the wastewater sector organisation, are 
significantly lower and distributed as follows: 
-  Sludge and soil testing costs (testing service providers indicate that those represent a 
very small proportion of total costs). These may be incurred by the UWWTP operators 
and/or further treatment operators, farmers and/or competent authorities. 

-  Administrative costs for wastewater treatment plant operators, for reporting purposes. 
-  Administrative costs (notably for reporting) and enforcement costs, borne by Member 

States authorities (discussed in section 3.1.2.4.) 

-  Payments  by  the  wastewater  treatment  plant  operators  to  farmers  for  the  receipt  and 

use of sewage sludge on agricultural land ("gate fees”). 

  Direct benefits 

Direct benefits linked to sludge use in agriculture: 

1.  The savings made by the UWWTP operators or subsequent treatment operators using the 
agriculture  route  as  a  sludge  management  option,  compared  to  other  routes58  (discussed 
below). 

58 Calculating benefits in terms of savings made in this way was also the approach taken in the 2014 evaluation 

27 

 
 
 
 
 
 
 
                                                 
 
 
 
 
 
 
 
 
 
 
 
 
2.  Potential savings for UWWTP operators or subsequent treatment operators as a result of 
certain  sewage  sludge  treatment  operations  compatible  with  sludge  land  spreading.  For 
example  anaerobic  digestion  reduces  the  volume  of  sludge  and  improves  dewaterability 
(lower water content). This reduces the cost for transport and sludge use in agriculture. 

3.  The  savings  made  by  farmers  for  not  using  mineral  fertilisers  (partial  replacements  of 

mineral fertilisers). 

Annex IV provides a more detailed overview of the cost and benefits of the Directive. 

  Comparison of costs of sludge use in agriculture compared to other management 

routes 

Table  2,  provided  in  Annex  III  (EQ  6)  presents  costs  and  benefits  of  different  sludge 
treatment  options.  It  shows that  costs  are high, and costs vary  inside  ranges  which  are very 
broad. 

However,  it  only  shows  the  costs  of  individual  treatment  options.  This  alone  does  not 
represent overall costs of a sludge management route, as the latter includes combinations of 
treatments and transport costs. The cost of a sludge management route should be calculated by 
aggregating operator costs linked to the implementation of the SSD. 

Estimating  costs  of  each  sludge  management  route  (agriculture  or  other  ways  to  use  or 
dispose of sludge) is  difficult. With equal  adopted technology  capital, operating and energy 
costs will vary not only from country to country, but also between different sites in the same 
country,  due  to  differences  in  labour,  transport  distances,  sludge  storage  requirements  and 
conditions, energy costs, and economies of scale made according to the size if the plants. This 
also explains the wide ranges observed for cost data on different treatment options. Also, the 
treatment techniques before use or disposal may be combined in multiple arrangements (e.g. 
thickening,  dewatering,  liming,  anaerobic  digestion,  drying  at  the  UWWTP),  further 
increasing  cost  data  variability.  Quantitative  information  on  the  volume  of  sludge  treated 
using different techniques or combinations thereof is very scarce.  

Certain costs are common across the different sludge management routes, e.g. transport costs, 
dewatering, drying and stabilisation. The agriculture route incurs less costs than other options 
as can be seen from the estimates (from the same study) reflected in the table below. 

It is therefore difficult to find aggregated data, i.e. which include costs of the combination of 
treatment(s) applied. 

Research  undertaken  by  the  JRC59  allows  to  compare  the  costs  of  different  sludge 
management  options  (not  including  the  cost  for  processes  at  the  WWT  plants).  They  were 
based  on  extensive  literature  review60,  stakeholder  consultation  and  own  cost  calculation 
taking into account different plant sizes and different dewatering levels of the sewage sludge: 

Results were synthetised in the following boxplot, which shows the different sludge managing 
options. In some cases, the cost of using sludge in agriculture is in the order of magnitude of 

59 Egle et al., 2023 (under development) 
60 Including, for instance, studies referred to in the table  2, presenting costs and provided in Annex III and the table below,  

which is an extract from it. Sometimes these studies provide averages and/or cover a very high number of observations  

28 

 
 
 
                                                 
incineration (mainly co-incineration in coal and cement plants). However, this is mainly due 
to some extreme values for both sludge management options, which makes the ranges of costs 
very broad and makes them overlap, but not representing typical situations (in some cases, the 
minimum or maximum is only based on one observation or calculation). The clear difference 
between  land  spreading  and  incineration  costs  becomes  clearer  when  looking  at  the  75% 
percentile.  In  75  %  of  the  cases,  landspreading  has  a  cost  below  ~200  €/tDM,  whereas 
incineration is in 75% of the cases more expensive than ~200 €/tDM. The cost for composting 
can be in the range of direct agricultural use (median value around 150 €/t DM). The final use 
of  composted  sludge  is  often  not  clear.  For  the  use  in  agriculture  additional  cost  such  as 
storing,  transport  and  spreading  need  to  be  considered.  With  regard  to  the  end  use  of  the 
composted sludge, it should be noted that a large portion is not applied to cropland. 

Costs of different sludge management options 

NB: The range of landfill costs considered here only covers countries which still landfill sludge. As can be seen 
in the appendix, landfill cost can be higher than 480. But in these countries no sewage sludge is landfilled. 

Overall, sludge use in agriculture broadly remains the most cost-effective option across data 
reviewed. 

  Comparison of cost-efficiency between agriculture use and incineration 

For incineration, the main alternative to sludge use in agriculture, the cost differential is the 
most substantial: 

2  studies  from  Germany  (mainly  based  on  German  data)  also  show  the  following  ranges  of 
aggregate costs for agriculture and mono-incineration (whether revenues  are included is  not 
known): 

Wiechmann et al., 2015 
Umweltbundesamt 2018 

Agriculture use 
(Cost-EUR/tDS) 
125-175 
160-320 

Mono-incineration 
(Cost-EUR/tDS) 
175-400 
280-480 

Across data reviewed, aggregated costs for (mono-)incineration come out as 1.5 to 3 times as 
expensive  as  sludge  use  in  agriculture  (even  10  times  in  some  examples  provided  from  the 
stakeholder consultation).  

-  The  cost-efficiency  also  remains  true  when  considering  energy  or  other  revenues  from 
incineration. This is mostly a waste disposal option with minor benefits for other actors 
and  downstream  users.  Modern  incinerators  recover  heat  and  energy  from  the  sludge, 

29 

 
 
 
 
 
largely dependent on the pre-treatments (e.g. dewatering, drying) applied. Yet, revenues 
from  these  recovery  processes  by  far  do  not  compensate  other  capital  and  operational 
costs  of  the  incineration  plant.  Some  sewage  sludge  incineration  ashes  are  used  as  a 
construction  material  (e.g.  for  road  construction),  but  the  economic  value  of  ashes  is 
negligible61.  

-  This  cost-efficiency  remains  true  in  the  rare  cases  when  considering  revenues  from  P-
recovery  are  included,  as  the  necessary  mono-incineration  step  is  the  most  expensive 
incineration technology and equipment and operational costs of the recovery technology 
are  high.  Revenues  of  such  production  would  only  partially  neutralise  the  high 
infrastructure and operational costs of such waste recovery process.62 

- 

P-recovery is marginal, at least today: at present only a negligible share of the sludge is 
incinerated and processed through this route. Today, across the EU, there are only about 5 
full  scale  plants  operating  or  under  permitting/construction,  located  in  the    Austria, 
Germany,  Netherlands,  and  Sweden63,  treating  currently  around  60,000  tons  of  sludge 
ash,  which  corresponds  to  about  (150,000 t DM,  which  is  negligeable).  Therefore,  such 
advanced  phosphorus  recovery  processes  are  hardly  relevant  for  this  backward-looking 
evaluation report. 

Calculation of savings from using the agriculture route: 

From the JRC data provided above, a graph can be derived to show the savings made by using 
sludge  in  agriculture  compared  to  the  three  co-incineration  and  the  mono-incineration  
options: 

If a hypothetical shift from the current sludge volumes from agriculture towards incineration 
were to occur, the additional cost would correspond to 41 – 488 million € per year, depending 
on the incineration technology assumed and based on 25 - 75 percentile cost data. For mono-
incineration only these additional costs would be of 391-488 million €/yr64. Mono-incineration 

61 Egle et al., 2023 (under development) 
62 Egle et al., 2023 (under development) 
63 ESPP (European Sustainabke Phosphorus Platform), DPP and NNP (2022) 
64 Egle et al., 2023 (under development) 

30 

 
 
 
 
 
                                                 
represents 50% of the total sludge incinerated. Other types of incineration, as can be seen on 
the  above  graph,  include  co-incineration,  e.g.  in  cement  plants,  possibly  accompanied  by 
energy recovery (“co-inc WTE” on the graph above).65 

Wood66  also  estimated  the  benefits  based  on  differentials  between  sludge  use  in  agriculture 
and  other  options  of  the  SSD  differentials  with  other  options  of  sludge  use  and  disposal. 
Based on available literature from two German studies (see Annex III), it was estimated that 
the average cost savings between agricultural use and incineration of dewatered sludge would 
amount to 150 € per ton of dry sludge (tDM)67. Based on the assumption (rather arbitrary) 
that between 30 and 70% of the sludge currently applied to agriculture would be treated more 
cost  intensively  by  incineration  in  the  absence  of  the  SSD,  the  agricultural  use  of  sewage 
sludge would result in aggregated cost savings for UWWTP operators of 100-240 million 
€ per year68. However, these figures present a lot of uncertainties, as regards the methods and 
assumptions made for the calculation. They should be considered as very indicative.69 

The 2014 Evaluation of the Directive had estimated that if the agriculture route were lost, to 
be replaced by incineration, the cost would be of the order of EUR 650 million per year70. 

  Benefits to farmers from the land spreading of sludge 

Farmers are the other key group which is impacted by the Directive, largely incurring savings 
as a result of sewage sludge use. They benefit from the application of sludge on agricultural 
land in 3 ways: 

-  The use of sewage sludge provides nutrients to plants, and thus partially replaces the 

production and use of mineral fertilisers and associated costs;  

-  Sewage  sludge  also  contains  organic  matter  that  contributes  to  improving  soil 
structure  and  reducing  soil  erosion,  moisture  holding  potential  and  buffer  capacity. 
Particularly in soils of low organic matter content (e.g. in southern Europe) may be a 
valuable asset to contribute to soil organic matter build-up; 
In  some  countries,  farmers  are  commonly  paid  by  the  wastewater  treatment  plant 
operators to accept the application of sewage sludge on their land, e.g. 100 €/tDM in 
Lithuania71  and  100-560  €/tDM  in  Germany72.  On-going  work  by  JRC  indicates  a 
potential  revenue  of  2-10  €/t  for  compost73.  Reports  from  Bulgaria  and  the  UK74 
suggest that farmers do not receive payments for sludge to be used on land. 

- 

Potential savings  associated with  the use of sewage sludge for farmers  have been estimated 
considering  the  levels  of  nutrients  present  in  sludge  as  indicated  in  the  Member  State 
implementation reports and assuming that all the nutrients brought by sludge would have been 

65 Egle et al., 2023 (under development) 
66 Wood, Support to the evaluation of the Sewage Sludge Directive (2022) 
67  Wood,  Support  to  the  evaluation  of  the  Sewage  Sludge  Directive  (2022)  Based  on  information  received  from  the 

stakeholder responses and the literature review 

68 Wood, (2022) - Support to the evaluation of the Sewage Sludge Directive (2022);  Details about the calculations are also 

provided in Annex III to this report, EQ6. 

69 Egle et al., 2023 (under development)  
70 Milieu, 2010 
71NB:  This  figure  was  obtained  from  one  interview  respondent.  There  is  mention  of  competition  of  dried  sludge  from 
industrial installations interested in co-incinerating and selling resulting carbon allowances to the market. These accept 
sludge free of charge and are willing to pay for longer distance transport, e.g., 400 km. 

72 This figure was obtained from one of the targeted questionnaire respondents. 
73 Egle et al., 2023 (under development) 
74 Information provided for reference, though the UK is not covered by this evaluation 

31 

 
 
                                                 
provided by use of fertilisers.75 It would range up to 96 €/tDM  for nitrogen and 44 €/tDM 
for  phosphorus.  However,  it  cannot  be  assumed  that  all  the  sludge  applied  to  agricultural 
land in Europe is associated with a pro rata monetary saving linked to avoidance of inorganic 
fertiliser  purchases:  due  to  the  significantly  lower  fertiliser  efficiency  of  sewage  sludge 
relative to mineral fertilisers and of availability of other sources of organic waste that can be 
recovered  on  land  with  benefit  to  agriculture,  namely,  manure  and  biowaste.  Also,  it  is  not 
clear what proportion of sludge is applied to agricultural land with a nutrient deficit. 

Other direct benefits which could not be quantified include: 

- 

- 

the organic matter brought to the soil by sludge (even though these amounts are small 
compared to the benefits from application of manure (livestock waste)) 

the  benefits  brought  by  sludge  as  soil  improver  (of  density,  mechanical  or  physico-
chemical properties of the soil) property of sludge. 

- 

the potential benefits of using organic fertiliser for productivity of land over time 

Finally, the implementation of the Directive allows the reduction of disposal and landfilling of 
sludge, which would have a positive environmental impact and an impact on the revenues of 
the different actors linked to the landfilling of waste. This benefit could not be quantified in 
view  of  difficulties  shown  at  the  beginning  of  this  section  on  estimation  of  costs  and  with 
scarcity of quantitative data on sludge routes and treatment. 

All  in  all,  provided  that  environmental  and  health  protection  is  safeguarded,  encouraging 
sludge use in agriculture brings significant financial benefits to both  UWWTP operators (or 
the  end  beneficiaries  of  saving  made  on  treatment)  and  farmers,  by  allowing  significant 
savings.  

2.1.2.2.     Externalities 

The  indirect  effects  of  the  Directive,  as  described  in  section  4.1.1,  can  lead  to  externalities 
which can be either positive or negative.  

Positive externalities include, first, the fact that the implementation of the Directive allow to 
prevent pollution of agricultural soil by heavy metals as a result of recovery of sewage sludge. 
Since sludge has an agronomic value and it is an economically attractive waste management 
option for the UWWTP operators, the Directive provides a minimum level of environmental 
protection for such activities.  

Second, the use of sludge in agriculture also prevents the depletion of natural resources which 
would  otherwise  result  from  mineral  fertiliser  use,  a  non-renewable  and  critical  resource  to 
the European Union economy. 

Third, sludge use in agriculture can also have positive effects on climate change. At present, 
the net combined effect of sludge management through the different routes is estimated to net 
emissions  of  1.2  million  tonnes  CO2-eq76  per  year.  If  done  in  a  sustainable  way,  sludge 
management has a potential to become a net sink of CO2, following a further reduction of the 
global warming footprint with up to 3 million tonnes CO2-eq per year. Using it in agriculture 

75 Wood, support to the evaluation of the Sewage Sludge Directive (2022) 
76 CO2-equivalent 

32 

 
 
 
                                                 
generally has a net negative carbon footprint, due, amongst others to the sequestration of CO2 
in  soils  and  its  potential  to  substitute  mineral  fertilisers,  produced  through  energy-intensive 
processes. Still, the absolute footprint from sewage sludge management is relatively small in 
comparison  to  operations  taking  place  upstream  (sewage  system  and  wastewater  treatment 
plants), estimated at around 25-30 million tonnes of CO2-eq per year.77 The agricultural sector 
as a whole produced 426 million tonnes of CO2 equivalent of greenhouse gases in 2015, about 
10 % of the EU’s total greenhouse gas emissions (excluding Land Use, Land Use Change and 
Forestry net removals) for that year78 . 

Other indirect effects can also cause negative externalities. As seen before, the application of 
sludge  on  land  can  generate  air  emissions,  notably  in  instances  of  over-application  of 
nitrogen. The potential application of sludge in excess of plant needs for nitrogen can lead to 
emissions of nitrous oxide (N2O) and ammonia (NH3), a gas with high greenhouse potential. 
Recent data would estimate the external cost of ammonia emissions at 2-20 EUR/ kg of NH3-
N emitted, knowing that 1 tonne of sludge could emit a up to 15-20 kg NH3 (these losses are a 
continuous process, but most losses occur shortly after application)79. Equipment inefficiency 
can also lead to air emissions, e.g. methane leaking from anaerobic digesters (mainly from old 
installations,  from  poor  design  and  maintenance)  or  dioxins,  furans  and  sulphur  dioxide 
emitted  by  incinerators.  Note  that  these  negative  externalities  are  also  relevant  for  other 
sludge destinations. 

Other  types  of  pollution  should  be  considered  too,  for  areas  where  the  effectiveness  of  the 
Directive  could  not  be  assessed  with  certainty,  notably  as  regards  the  list  of  contaminants 
covered by the Directive and whether the latter ensures high level of environmental and health 
protection.  This  will  be  discussed  in  section  4.3.2  of  the  Directive.  Pollution  from  other 
contaminants  (e.g. PFAS, pharmaceuticals,  microplastics) that are not  regulated by the SSD 
cannot  be  quantified,  and  neither  can  be  the  spread  of  antibiotic  resistance  (which  they 
contribute to). Similarly, the  over-application of  nitrogen  could  also  result in  eutrophication 
though there is no evidence that this is the case from use of sewage sludge. 

2.1.2.3.     Factors affecting cost-efficiency 

A very wide range of factors affect costs and the cost-efficiency of the implementation of the 
Directive,  which  results  in  a  wide  variety  of  situations  in  the  Member  States.  There  is  no 
specific pattern, for instance between  new or old Member States, or North to  South,  as this 
depends very much on local situations. These factors are notably: 

-  The size of urban dwellings (economies of scale can be made with treatment equipment of 

bigger capacity). 
-  Economies of scale. 
-  Agronomical characteristics of sewage sludge depending on the input material. 
-  Competition  on  a  local  level  with  other  available  organic  fertilisers,  such  as  manure  or 

compost. 

77 Data from JRC policy report on the UWWTD (not yet published at the time of writing this report). 
78 Eurostat (2021 
79 Brink et al., 2011 

33 

 
 
 
 
                                                 
-  Distance  from  wastewater  plants  to  suitable  agricultural  land.  In  practice,  a  study  by 
Amann et al.80 found that distances do not exceed 50 km (on average less than 20 km) and 
could  be  significantly  lower.  Transport  distances  to  incinerators  are  in  average 
significantly  longer  (average  150  km),  resulting  in  higher  transportation  cost.  For 
countries with lower developed incineration capacities, the transport distances can be even 
higher. 

-  Energy  costs,  which  are  notably  cost  drivers  for  thermal  treatments,  including 

incineration.  

-  Average  labour  cost.  According  to  the  Milieu  2010  study,  operating  costs  constitute  a 
large  proportion  of  total  sludge  management  costs,  particularly  for  land  spreading  with 
values recorded between 65% and 70%. According to Eurostat, average 2019 labour costs 
in the wider water and waste sector range from €5-€42 / hour in different Member States81. 
-  The  variety  of  sludge  treatment  technologies  applied  across  the  EU.  Thermal  drying 
technology is  mainly  applied in  EU-15 countries,  composting and  chemical  stabilization 
with lime are used considerably in Finland and Poland.82 Eurostat reports high composting 
rates above 25% for CZ, FR, CY, LT, HU, SK, FI, SE. The infrastructure/equipment cost 
is reported to be relatively uniform across the EU83. 

-  Possibly: the continuous implementation of the UWWTD, resulting in higher volumes of 
sludge  generated  and  to  be  managed  where  additional  wastewater  treatment  capacity  is 
developed.  However,  this  remains  unsure  as  increased  sludge  processing  (dewatering, 
anaerobic  digestion)  may  counterbalance  increases  due  to  the  greater  processing  of 
wastewaters.  Where  the  proposal  for  a  revised  UWWTD  introduces  stricter  treatment 
requirements,  this  may  also  impact  the  amount  of  sludge  generated  as  well  as  its 
composition and agronomic value (including higher level of contaminants)84.  

-  Technology developments such as energy efficiency improvements or innovations such as 
secondary activated sludge treatments in WWTPs lead to changes in the cost structure of 
sludge treatment (e.g. anaerobic digestion as a technique that reduces sludge volumes). 

-  The  structure  of  the  water  and  sanitation  sector.  Financing  structures  vary  considerably 
across Member States and local authorities. Some  operate regulated tariffs which aim for 
cost recovery and others operate local or national subsidy systems that are often associated 
with significant underinvestment in equipment replacement in the sector. In some Member 
States,  private  sector  operators  are  engaged  in  time-bound  concession  contracts  and 
depending  on  the  structure  of  such  concessions,  longer  payback  investments  may  be 
discarded  to  the  detriment  of  sanitation  users,  taxpayers,  or  environmental  quality 
stakeholders. Member States that have joined the EU after 2003 have made significant use 
of  EU  structural  funds  and  illustrated  in  interviews  related  to  Lithuania,  Bulgaria,  and 
Romania. 

-  Applicable  rules  at  regional  level,  notably  whether  more  stringent  requirements  are 
applied,  and  whether  certification  systems  (the  voluntary  schemes  described  in  section 

80 Amann et al. (2021) Operation and Performance of Austrian Wastewater and sewage sludge treatment. Water 2021, 
13(21), 2998; https://doi.org/10.3390/w13212998  (indicate max 10 km for wet sludge and max 20 km for dewatered sludge) 
81 Eurostat data. 
82 Kelessidis A, Stasinakis AS (2012)..  
83  According  to  an  interview  with  multinational  water  operator  multinational  water  companies  require  suppliers  to  quote 

unique prices irrespective of MS destination.  

84 The proposal is now subject to negotiations by Council and Parliament 

34 

 
 
                                                 
4.1.1) in  are in place.  For the latter,  associated  costs are small85  as  a percentage of total 
average costs of the agriculture application option. 

Considering this heterogeneity of factors and the fact that local conditions and the individual 
specificities of the WWTPs strongly influence sludge management choices, the enabling and 
flexible nature of the SSD is seen as a cost-efficient feature, as it allows decision-making to 
be undertaken on the basis of local factors. However, the uncertainties as regards the costs and 
benefits of potential or affirmed indirect effects of the Directive do not allow to conclude on 
the overall cost-effectiveness of the Directive. Locally, cost-effectiveness will also be further 
affected  by  national  or  regional  applicable  rules  and  practices  such  as  the  setting  of  more 
stringent  requirements.  Finally,  it  is  not  clear  whether  negative  externalities  linked  to 
pathogens  or  organic  micro-pollutants  are  missed  in  countries  that  do  not  impose  quality 
restrictions in relation to these aspects. 

Stakeholders views on cost-benefits:  

Results from the OPC show a tendency to value the social and environmental benefits that the 
SSD  brings  more  than  its  costs.  This  statement  is  valid  for  all  stakeholder  types,  with  the 
following two exceptions: NGOs viewed the costs as outweighing the benefits under all sub-
questions, and EU citizens were split. 

2.1.2.4.     Administrative costs and reporting 

The  administrative  costs  borne  by  Member  States  linked  to  the  implementation  of  the  SSD 
include monitoring, reporting and enforcement and can be estimated at around EUR 77,000 to 
EUR 80,000 per year per Member State on average86. This can be considered as moderate in 
comparison to other environmental directives. Details on how these costs were estimated are 
provided in Annex III, EQ 10. 

However, the reporting system shows deficiencies. As noted in section 4.1.1, it only allows to 
assess the effectiveness of the Directive to an extent.  

-  On existing reporting requirements, widespread gaps were noted in reporting, suggesting 
room for improvement on data collection and record keeping within some Member States. 
-  Data  reported  by  Eurostat  and  in  the  Member  State  implementation  reports  lack 
comparability and granularity. For instance, data from Eurostat indicate the quantities of 
sludge  which  undergo  composting,  but  the  destination  of  that  composted  sludge  is 
unknown.  Some  of  it  is  eventually  used  in  agriculture,  so  this  fraction  should  then  be 
counted as sludge used in agriculture. 

-  Further,  there  is  room  for  simplification  and  alignment  between  data  reported  for  the 
implementation  of  the  SSD,  that  of  the  UWWTD,  and  data  provided  to  the  EEA  and 
Eurostat87. Reporting obligations could clarify analytical methods respectively prescribed 
by  the  two  Directives,  links  between  the  two  sets  of  reporting  requirements88  and  align 
reporting cycles. 

85  For  example,  for  the  Swedish  REVAQ  systems,  testing  costs  range  from  €0.5-3/tDS  and  0.5-1/tDS  for  sludge  and  soil 
respectively.  Certification  costs  for  REVAQ  WWTPs  range  from  €2-3/tDS,  with  an  additional  €0.2-5  fee  for  a  third-
party auditor. 

86 Wood report on the evaluation of the SSD (2022) - Details of calculations are provided in Annex III. 
87 “Ex-post evaluation of certain waste stream Directives”, EC (2014); “Fitness check of monitoring and reporting obligations 
arising  from  EU  environmental  legislation”,  EC  (2017);  SWD(2019)700  final  of  13.12.2019  on  the  evaluation  of  the 
UWWTD. 

88     SWD(2019) 700 final of 13.12.2019.  

35 

 
 
                                                 
-  The  Directive  requirement  to  take  into  account  plant  needs  before  the  application  of 
sludge  on  soil  is  not  linked  to  any  reporting  obligation  and  it  would  help  to  monitor 
possible  over-application  of  nutrients.  This  was  also  noted  by  some  stakeholders.  These 
aspects  are  closely  monitored  in  Nitrate  Vulnerable  Zones  under  Directive  91/676/EEC, 
but they cover only a proportion of agricultural land in Europe. 

-  The  Directive  does  not  require  Member  States  to  provide  reasons  for  adopting  stricter 

requirements. 

As of 2023, as a result of Regulation 2019/1010, which aimed to improve the transparency of 
environmental  reporting,  amending  the  SSD,  Member  States  are  required  to  report  on  the 
implementation of the Directive annually as well as to report spatial data on the agricultural 
areas where sludge is to be applied. This will improve the reporting scheme, which currently 
is not only 3-yearly, but, as shown in section 4.1.1, is limited. Such assessments will also be 
eased  within  the  general  framework  of  improvement  of  reporting  and  monitoring  of 
environmental legislation89, and upcoming obligations under the Common Agricultural Policy. 

This  will  also  increase  costs  of  monitoring  and  reporting  (for  the  SSD),  for  Member  States 
and  relevant  stakeholders  (UWWTPs  and  possibly  farmers).  However,  in  addition  to  the 
advantages described above, this cost increase can be mitigated by re-using data from existing 
data sources from other policy areas, such as cadastral data or data collected in the context of 
the  Integrated  Administrative  and  Control  System  for  the  management  of  the  Common 
Agricultural Policy and Regulation (EU) No 1306/201390. 

2.1.3. 

4.1.3. Coherence 

Since  the  adoption  of  the  Directive,  both  the  policy  and  regulatory  landscapes  have 
considerably  evolved.  Technology  and  scientific  knowledge  have  progressed  as  well.  It  is 
therefore  opportune  to  assess  the  coherence  of  SSD  with  related  Union  product  and 
environmental  legislation  and  flagship  policy  initiatives,  notably  in  recent  years,  in  the 
context of the Green Deal. This section presents the analysis of the coherence of the Directive 
with the key EU policies and legal instruments that have relevance to its implementation and 
vice versa. Additional assessments are also reflected in Annex III, Eqs 12-14. 

2.1.3.1.     Internal coherence of the Directive 

While  the  literature  review  and  the  consultations  carried  out  find  the  Directive  internally 
coherent, that is, it does not include contradicting or obsolete provisions.   

The legal basis of the Directive relates to the functioning of the internal market. This does not 
appear  fully  coherent  with  its  objectives,  in  particular  considering  that  the  EU  Treaty  has 
changed since its adoption, and now includes a specific legal basis for environmental policy 
making. The defined  aims  of the Directive, recitals  and measures which it lays down, show 
that the objective of recovery of waste and protection of the environment and human health is 
central  to  the  Directive.  This  is  in  line  with  the  time  of  adoption  of  the  Directive  when 
Articles 100 and 235 of the Treaty establishing the European Economic Community formed 
the  legal  basis  for  environmental  legislation  predating  a  specific  environmental  policy  legal 

89 This framework also includes spatial monitoring, emissions e.g. of methane, including by means of satellites and in real 

time. 

90  Commission  Implementing  Decision  (EU)  2021/2252  of  16  December  2021  amending  Decision  94/741/EC  concerning 

questionnaires for Member States reports on the implementation of certain Directives in the waste sector. 

36 

 
 
                                                 
base in the Treaty. While its second recital refers to disparities between the Member States’ 
provisions  on  the  agricultural  applications  of  sewage  sludge  which  might  affect  the 
functioning of the common market, its potential to reduce barriers to trade in sewage  sludge 
across Member States is  very limited.  Neither the design of the  regulatory measures of the 
Directive (especially its Article 12 and the fact that it does not regulate treatment of sludge), 
nor the legal  developments  that have been pursued by the Member States or at Union level 
since  the  adoption  of  the  Directive,  ensure  that  any  pursuit  and  impact  of  the  Directive  in 
relation to the functioning of the internal market can be effective.  

The scope for removing  potential barriers to internal trade in sewage sludge for agricultural 
use is limited to those Member States that remain at the same level of regulation. Over time 
this is reduced to a third of Member States only. This potential for cross-border movements of 
sewage  sludge  is  also  considerably  limited  due  to  the  fact  that  the  Directive  maintains  the 
waste  status  of  sludge  (which  impacts  the  costs  of  transportation  linked  to  administrative, 
reporting  and  safety  requirements  related  to  the  shipments  of  waste)  and  the  very  low 
economic  value  of  sewage  sludge.  Also,  it  appears  that,  like  for  biowaste,  the  distance  of 
supply of sewage sludge to the farmland remains within 50 km from the UWWTPs where it is 
generated  on  account  of  the  transportation  costs91.  Furthermore,  following  the  adoption  in 
2019  of  the  Fertilising  Products  Regulation,  the  safety,  quality  and  labelling  of  fertilising 
products  derived  from  certain  treatment  of  sewage  sludge  are  subject  to  harmonised 
regulation at Union level to enable their free trade throughout the EU92. Article 6 of Directive 
2008/98/EC on waste also provides a legal basis for the Commission to adopt Implementing 
Acts to develop Union level end-of-waste criteria and this mandate may cover substances and 
materials  derived  from  processed  sewage  sludge  that  are  not  covered  by  the  Fertilising 
Product  Regulation.  This  Regulation,  along  with  the  Waste  Framework  Directive,  therefore 
offers  the  regulatory  tools  at  Union  level  to  address  barriers  to  marketing  of  such  materials 
derived from sewage sludge in the EU; therefore limiting any potential indirect benefit from 
the SSD since the SSD does not aim to regulate the marketing of sewage sludge, but only its 
specific  use  on  agricultural  land.  In  view  of  that,  and  in  view  of  the  fact  that  the  sewage 
sludge  management  policies  are  at  the  intersection  of  several  Union  policies,  when  the 
Directive  is  subject  to  a  revision,  the  determination  of  the  legal  basis  of  that  initiative  will 
have to be based on the aim and the content of its measures.  

With  regard  to  the  coherence  of  its  provisions,  in  addition  to  weaknesses  of  the  reporting 
requirements  identified  in  section  4.1.2.4,  certain  definitions  would  benefit  from  further 
clarity.  The definitions of sewage sludge and treatment  are very broad,  covering all sewage 
sludge  and  all  treatment  operations.  This  has  raised  questions  of  interpretation  in  terms  of 
which sources of sludge fall within the scope of the Directive under Article 2(a)(iii) since the 
points (i) and (ii) are defined in a restrictive way in view of limiting inputs and therefore their 
likely level of contamination. With regard to the definition of sludge, there may be benefit in 
bringing  clarity  on  the  sources  of  sewage  sludge,  in  particular,  where  excluding  certain 
sources may offer more effective pollution prevention strategies. With regard to the definition 
and  requirements  on  treatment  of  sludge,  the  directive  requires  sludge  to  be  treated  before 
spreading  on  land,  but  it  is  not  prescriptive  about  the  kind  of  treatment(s)which  it  should 
undergo.  Some  Member  States  regulate  this  in  more  detail  in  view  of  limiting  level  of 

91 Saveyn H, Eder P., 2013. JRC87124 
92 See Component Material Categories 12 and 13 of the Fertilising Product Regulation.  

37 

 
 
                                                 
contaminants and facilitating its use on land. The broad rules of the Directive have also raised 
interpretation  issues  on  whether  the  outputs  from  certain  treatments  which,  according  to 
national or Union legislation, are recognised as products (i.e. no longer waste) remain subject 
to the regulation of SSD, or it only concerns the use of waste sludge on land. SSD also does 
not address situations where sludge is mixed with other material before application onto land 
(e.g. composting together with another source of organic waste), which is common practice. 
The  above  aspects  would  benefit  from  clarification  to  reduce  the  discrepancies  In  national 
implementation and the conditions on the wastewater and sludge treatment operators.  

2.1.3.2.     Coherence with Union policies and legal instruments  

Under  the  umbrella  of  the  European  Green  Deal93  (EGD),  the  SSD  is  at  the  intersection  of 
several  Union  policies,  notably  circular  economy  and  the  industrial  policy  which  promotes 
nutrient  recovery  and  Unions  strategic  independence  on  mineral  fertilisers  and  policies  for 
attaining  zero  pollution,  climate  neutrality  and  energy  independence.  This  section  assesses 
coherence  with  the  key  policy  frameworks  and  legislation  which  are  most  relevant  and 
interlinked with he SSD. More information on coherence, notably with other instruments, is 
provided in Annex III. 

 

Circular Economy and nutrient recovery 

Two Action Plans for Circular Economy have been developed and rolled-out over the lifetime 
of  the  Directive.  Its  contribution  and  synergies  with  the  first  one,  launched  in  2015,  is 
discussed in Annex III. The new Circular economy action plan (CEAP)94, one of the main 
building  blocks  of  the European  Green  Deal  to  attain  a  sustainable  and  climate  neutral 
economy, sets  out  a vision and outlines new initiatives to  further the transition  to  a circular 
economy while reducing the pressure on natural resources, with a notable focus on food and 
nutrients, and creating sustainable growth. 

The  SSD  pursues  the  core  objective  of  the  circular  economy  of  facilitating  recovery  of 
nutrients  (phosphorus,  nitrogen  and  carbon)  and  thereby  also  contributing  to  the  EU’s 
strategic  aim  to  reduce  its  dependency  on  imports  of  nutrients  from  third  countries.  The 
CEAP, in view of the on-going review of UWWTD, calls for improving synergies with SSD 
and increase the ambition level to remove nutrients from wastewater and make treated water 
and sludge ready for reuse, supporting more circular, less polluting farming, in particular, in 
support of the future EU Integrated Nutrient Management Plan95. It also calls for measures 
towards  energy  efficiency  and  carbon  neutrality  as  well  as  a  better  application  of  the 
‘polluters pays’ principle. 

At present, about half of the P contained in sludge is irreversibly lost through co-incineration 
and landfilling. If these flows were to be fully redirected to agricultural uses, nutrient volumes 
equivalent to 10% of the phosphate rock used in mineral fertilisers could be substituted with 
sewage sludge derived materials96. 

93 COM(2019)640 final of 11.12.2019.  
94 COM(2020)98 final of 11.3.2020. 
95 The links with the Integrated Nutrient Management Plan initiative are detailed in Annex III. 
96 Egle L. et al. (under development) 

38 

 
 
                                                 
Sewage  sludge  falls  in  the  definition  of  waste  under  the  Waste  Framework  Directive 
(WFD). The SSD facilitates the application of the waste hierarchy set by the WFD, whereby 
recovery  takes  priority  over  energy  recovery  (so  called  “waste-to-energy”)  or  disposal  (e.g. 
landfilling)97.  The  SSD  complements  the  WFD  as  a  lex  specialis  which  translates  the  WFD 
principles of circular economy and recovery of secondary raw materials and requirements for 
safe management of waste for sewage sludge. The recovery of nutrients from sludge is  also 
facilitated  by  the  Fertilising  Product  Regulation  (FPR)98,  which  regulates  making  EU 
fertilising  products  available  on  the  single  market.  It  encourages  the  production  and  use  of 
fertilising products of domestic organic or secondary raw material origin and, since July 2022, 
it  provides  harmonised  criteria  for  end-of-waste  status  to  certain  materials  recovered  from 
sewage sludge.99 In this way the FPR contributes to the well-functioning of the EU market for 
secondary raw materials for derivates of sludge as a result of incineration and phosphate salts 
precipitation.  Compost  and  digestate  resulting  from  the  recovery  of  sewage  sludge  are  not 
covered as there no EU-wide end-of-waste criteria100. 

The OPC results showed that a third of respondents agree and a similar share disagree that the 
SSD  is  coherent  with  the  WFD  and  FPR.  From  the  OPC,  27%  of  stakeholders  (of  172 
respondents)  agreed.  37%  disagreed  and  13%  were  neutral.  The  remaining  respondents  did 
not know/no opinion. The feedback from targeted surveys showed that most stakeholders did 
not  consider  the  link  between  the  Fertilising  Products  Regulation  and  the  SSD  was  made 
explicit  enough  (62%,  n=38  thought  ‘not  at  all’  or  ‘to  some  extent’).  Additional  comments 
indicated  that  the  Fertilising  Product  Regulation  does  not  cover  many  sludge-derived 
materials, thus sewage sludge is not fully in scope. Some stakeholders have indicated that the 
absence  of  end-of-waste  criteria  for  sludge-derived  materials  impacts  the  trust  in  these 
materials101.  This  is  linked  to  the  call  by  stakeholders  for  the  Commission  to  consider 
expanding  the  scope  of  end-of-waste  criteria  for  further  sludge  derived  substances.The 
objectives  pursued  by  the  SSD  are  also  consistent  with  the  Farm  to  Fork  strategy  for  the 
sustainable  production  of  food102  which  targets  to  cut  nutrient  losses  from  agriculture  by  at 
least  50%,  and  to  reduce  the  use  of  mineral  fertilisers  by  at  least  20%  by  2030.  The  SSD 
requirements aim to improve the agronomic performance of soils and limit use of fertiliser to 
what  is  required  by  plant  nutrient  needs  to  prevent  pollution  of  soils  and  leachate  (and 
therefore  loss)  of  nutrients  through  the  soil  (which,  in  the  case  of  nitrogen  and  phosphorus, 
would cause eutrophication). The coherence may be further strengthened, if the Directive is 
adapted to scientific and technical progress, notably on the set of pollutants which it regulates, 
and if it could be guaranteed that sludge application is aligned with plant needs through more 
robust regulatory tools. 

97 Article 4 of Directive 2008/98/EC. The Sewage Sludge Directive is a lex specialis to the WFD and encourages recovery of 
nutrients regulating in detail the conditions for recovery of sewage sludge in application on agricultural  land in a way 
that does not endanger the environment and human health. 

98 Regulation (EU) No 2019/1009. 
99 Substances recovered from sludge through thermal treatments e.g. thermal oxidation and pyrolysis.  
100  Commission  Delegated  Regulation  (EU)  2021/2086  and  2021/2087  amending  Annexes  II  and  IV  to  Regulation  (EU) 

2019/1009  

101 Aqua Publica Europea, 2019 
102 COM(2020)381 final of 20.5.2020. 

39 

 
 
                                                 
 

Zero pollution policy 

The European Green Deal develops a zero pollution vision for 2050 and the subsequent Zero 
Pollution Action Plan (ZPAP)103, which aims at preventing pollution for air, water and soil 
pollution  and  achieve  levels  no  longer  considered  harmful  to  health  and  natural  ecosystems 
and  at  securing  soil  quality.  The  SSD  contributes  to  that  policy,  through  its  objective  to 
prevent  harmful  effects  on  soil,  vegetation,  animals  and  man,  in  general  and  specifically  as 
regards prevention of pollution by heavy metals. ZPAP reflects the SSD’s role in the nutrient 
recovery from wastewater supporting more circular, and, as per the objectives of the SSD, less 
polluting farming. The ZPAP calls for addressing emerging pollutants such as microplastics 
and micropollutants, including pharmaceuticals, both in the revision of the UWWTD as well 
as assessing the impact on nutrient recovery from sludge. 

The EU Soil Strategy for 2030104, adopted in 2021 as part of the European Green Deal, sets 
out  a vision and measures to  protect  and restore soils and ensure their sustainable use.  This 
Strategy refers to the evaluation of the SSD, since the latter can contribute to sustainable use 
of  soil,  and  to  as  the  only  legislation  with  quality  standards  for  agricultural  soil  at  the  EU 
level. The strategy also announces a new Soil Heath Law, which the Commission is working 
on105.  It  may  offer potential  to  complement the implementation  of the  SSD, in  particular,  in 
relation  to  the  definition  of  soil  health,  the  soil  monitoring  provisions  (e.g.  for  certain  soil 
pollutants) and the requirements on sustainable soil management and by pursuing an adequate 
integration  and  coordination  of  soil  and  water  management  policies.  The  latter  aspect  is  of 
particular  relevance  in  view  of  the  difficulties  encountered  in  the  assessment  of  the 
effectiveness of the SSD on soil protection and the role of sludge use in the overall approach 
to soil protection, in particular, in view of the various pollutants that are relevant. Addressing 
sewage  sludge  in  isolation  may  lead  to  measures  that  unnecessarily  penalize  against  other 
sources  that  are  not  all  regulated  and  provide  trace  metals  (phosphates,  animal  waste, 
fungicides). 

This shows that pollution prevention policy instruments work in synergy with the Directive, 
towards common and complementary objectives. However, at operational level, in view of the 
assessment made in section 4.1.1 on Effectiveness, the adaptation of the Directive to the latest 
scientific  and  technical  progress  (notably  on  the  set  of  pollutants  to  be  covered  and  their 
appropriate  limit  values)  would  be  needed  to  fully  ensure  alignment  with  the  objectives  of 
ZPAP  and  EU  Soil  Strategy,  notably,  it  would  need  to  be  ensured  that  sludge  use  in 
agriculture is compatible with the objective of 30% reduction of microplastics release into the 
environment  set  by  the  ZPAP.  Adaptation  to  technical  progress  would  also  foster  the 
implementation of innovative solutions for sustainable management of sewage sludge, taking 
into consideration in particular the outcomes of EU funded research and innovation projects. 

The  Urban  Waste  Water  Treatment  Directive106  sets  requirements  for  the  collection  and 
treatment of wastewaters across the EU, to protect the environment from the adverse effects 
of  discharges  of  urban  wastewater.  Under  Article  14  of  the  UWWTD  as  it  stands,  Member 
States  “shall  re-use  sludge  whenever  appropriate’  and  ‘disposal  routes  shall  minimise  the 

103 COM(2021)400 final of 12.5.2021.  
104 COM(2021)699 final of 17.11.2021.  
105  The  Call  for  Evidence  for  the  initiative  available  here:  https://ec.europa.eu/info/law/better-regulation/have-your-

say/initiatives/13350-Soil-health-protecting-sustainably-managing-and-restoring-EU-soils_en  

106 91/271/EEC 

40 

 
 
                                                 
adverse  effects  on  the  environment’.  The  evaluation  of  this  Directive107  concluded  that  the 
revision of the UWWTD should consider its potential to contribute to the 2020 EU Circular 
Economy Action Plan for sludge management and nutrient recovery, in particular, to highlight 
the  value  of  sewage  sludge  as  a  source  of  nutrients  and  improve  consumer  confidence  and 
sewage sludge access to the market.  

The evaluation also highlighted that (1) removing pollutants from wastewater can increase the 
contamination  of  sludge,  with  a  risk  of  spreading  these  pollutants  if  contaminated  sludge  is 
used for agricultural purposes without sanitisation/decontamination steps and (2) that control 
at  source of targeted pollutants  would reduce treatment  requirements.  It  also  concluded that 
the  two  Directives  are  complementary,  but  that  there  is  room  for  better  alignment  in  two 
areas: 

-  On the definition of sludge: the two Directives define sludge slightly differently, with the 

SSD not being limited to sludge from urban wastewater108. 

-  On reporting obligations to clarify analytical methods respectively prescribed by the two 
Directives,  links  between  the  two  sets  of  reporting  requirements109  and  align  reporting 
cycles.  The  latter  was  confirmed  by  stakeholders  who  indicated  that  aligning  reporting 
requirements would reduce burden and complexity as sludge is usually not dealt with by 
water authorities. 

The extent to which UWWTP operators track pollution and pass on information to farmers on 
possible  substances  beyond  those  covered  by  the  UWWTD  and  the  SSD  is  also  unclear. 
Consultation activities carried out for the evaluation of the SSD showed that Member States 
and  stakeholders  remain  in  agreement  that  the  two  directives  are  broadly  coherent  and  that 
there  is  potential  to  improve  coherence  in  reporting  obligations  and  thus  increase  synergies 
between them. 

The proposal for a revised UWWTD110 offers opportunity to improve the coherence between 
the  two  Directives  addressing  the  aspects  identified  in  its  evaluation.  The  revision  of  the 
UWWTD  will  certainly  have  implications  on  sludge  management,  in  particular  on  the 
composition of sludge and, as such, nutrient recovery potential due to the diversity and level 
of  contaminants  present.  This  would  also  impact  the  choice  of  treatment  options  or  the 
availability/feasibility  of  treatment  and  the  potential  uses  of  sludge.  The  following  main 
impacts can be expected from the revised Directive as proposed by the Commission: 

-  No significant changes are expected, since the proposal does not significantly change the 

rules triggering wastewater treatment obligations; 

-  More  efforts  are  foreseen  in  the  proposal  for  a  revised  UWWTD  to  better  monitor  ‘non 
domestic’  (mainly  industrial)  pollutants  in  the  inlets  of  the  wastewater  treatment  plants. 
On  that  basis,  Member  States  will  be  required  to  track  these  pollutants  in  the  collecting 
networks  in  order  to  try  to  reduce  their  releases  at  source.  When  necessary,  discharge 

107 SWD(2019) 700 final of 13.12.2019. 
108 Art 2(10) UWWTD: ‘Sludge’ means residual sludge, whether treated or untreated, from urban wastewater treatment plants 

Art 2 of the SSD: ‘sludge’ means:  
(i)  residual  sludge  from  sewage  plants  treating  domestic  or  urban  waste  waters  and  from  other  sewage  plants  treating 

waste waters of a composition similar to domestic and urban waste waters; 

(ii) residual sludge from septic tanks and other similar installations for the treatment of sewage; 
(iii) residual sludge from sewage plants other than those referred to in (i) and (ii) 

109  SWD(2019) 700 final of 13.12.2019.  
110 Proposal for a revised Urban Wastewater Treatment Directive (europa.eu) 

41 

 
 
                                                 
permits of industries connected to the public collecting system should be reinforced. This 
is  expected  to  improve  the  quality  of  the  incoming  waters  and  consequently  of  the 
produced sludges and their likelihood for safe use in agriculture; 

-  On  the  other  hand,  more  efforts  are  planned  to  better  capture  and  treat  stormwater 
overflows  and  urban  runoff,  increasing  the  risk  of  concentration  of  microplastics  in 
sludge.   Again  a  systematic  monitoring  of  microplastic  in  the  inlets  of  the  plants  is 
foreseen and should help to apprehend the potential problem. This should contribute to the 
assessment of microplastics in sludge and the likelihood of safe use in agriculture, should 
it be considered necessary to further regulate this pollutant in the revision of the Sewage 
Sludge Directive; 

-  The  energy  neutrality  target  as  proposed  in  the  revised  UWWTD  but  also  the  recently 
adopted communication on Re-Power EU will increase the incentive for digestion of the 
sludge. This tendency is expected to increase also under the pressure of market price for 
gas. The impact on the use of sludge in agriculture would need to be further examined, but 
this would affect the drivers of sludge management routes: favouring anaerobic digestion 
would  have  an  effect  on  costs  and  sludge  quality  (usually  improved).  It  can  also  affect 
distances to farmland.  

-  New  monitoring  requirements  under  the  UWWTD  will  be  aligned  to  the  parameters 
included  in  the  SSD  (see  section  above  on  monitoring  and  preventing  non  domestic 
pollution in wastewaters).  Reversely, following the findings of the Impact Assessment on 
the  revision  of  the  UWWTD  in  relation  to  microplastics,  these  contaminants  were 
identified  as  one  of  those  which  deserve  specific  attention  and  further  examination.  In 
view  of  that,  the  future  assessments  underpinning  the  review  of  the  SSD  should  also 
consider  monitoring  or  regulatory  intervention  on  sludge  use  in  agriculture.   Besides 
microplastics, and based on the best practices in place in some advanced Member States 
(e.g.  the  REVAQ  system  in  Sweden),  the  overall  objective  will  be  to  ensure  a  full 
coordination between both directives so that sludge production and use can be monitored, 
tracked  and  improved   along  the  whole  chain–-  from  wastewater  production  through 
treatment up to the use of sludge in the fields and their possible impacts on soils. The first 
elements of this approach are included in the proposal of review of the UWWTD. 

 

EU energy and climate policies 

The EU energy policy aims at ensuring supply and reducing dependency  from imports from 
outside the EU, while moving towards a low-carbon economy. 

The  Renewable  Energy  Directive111  sets  a  target  for  the  share  of  renewable  energy  in  the 
transport sector: it should reach 14% of the final consumption of energy by 2030. A share of 
this  renewable  energy  should  be  fulfilled  by  advanced  biofuels  and  biogas  from  feedstock, 
which includes sewage sludge.  

The  (revised)  Energy  Efficiency  Directive112  sets  targets  for  energy  efficiency  by  2030, 
notably  on  renewable  energy.  In  March  2022,  in  its  REPowerEU  Communication113,  the 
Commission outlined a plan to advance that target to well before 2030 in view of increasing 
Union’s  independence  from  Russian  fossil  fuels  and reduce  EU  demand  for  Russian  gas  by 
two thirds before the end of 2022. The use of sewage sludge for the production of biogas or 

111 Directive (EU) 2018/2001 on the promotion of the use of energy from renewable sources. 
112 Directive 2012/27/EU on energy efficiency. 
113 COM(2022)108 final of 8.3.2022. 

42 

 
 
                                                 
for energy recovery through incineration can help achieve the target set by the two Directives 
and REPowerEU. These energy policy goals therefore influence national sludge management 
policies  and  stakeholder  decisions  and  the  amount  of  sludge  that  would  ultimately  be 
available and used for agricultural purposes compared to other uses.  

The  Directive  is  also  of  relevance  to  the  Union’s  climate  neutrality  objectives.  As  seen  in 
section  4.1.2.2  (assessing  externalities),  using  sludge  in  agriculture  generally  has  a  net 
negative  carbon  footprint,  due,  amongst  others  to  the  sequestration  of  CO2  in  soils  and  its 
potential  to  substitute  mineral  fertilisers,  produced  through  energy-intensive  processes.  The 
absolute  footprint  from  sewage  sludge  management  is  relatively  small  in  womparison  with 
operations  that  take  place  upstream  (sewage  system  and  wastewater  treatment  plants), 
estimated at  around 25-30 million  tonnes of CO2-eq per  year.114  The agricultural  sector as  a 
whole produced 426 million tonnes of CO2 equivalent of greenhouse gases in 2015, about 10 
% of the EU’'s total  greenhouse gas emissions  (excluding Land Use, Land Use Change and 
Forestry  net  removals)  for  that  year  (Eurostat,  2021).  In  view  of  this,  the  Methane 
Strategy115 notes that the UWWTD and SSD have a contributing impact but that they do not 
specifically tackle emissions of greenhouse gases. It refers to the review of the UWWTD and 
the  evaluation  of  SSD  as  opportunities  for  the  Commission  to  consider  taking  measures  to 
limit the emission of greenhouse gases from sewage sludge management.  

Overall,  the  carbon  footprint  for  the  different  sludge  management  routes  differs.  The  direct 
use-on-land  of  untreated  or  lime  stabilised  sewage  sludge  has  a  strong  net  negative  carbon 
footprint, and can therefore act as a climate change mitigation strategy, in contrast to sludge 
incineration  pathways116.  However,  the  more  contaminated  sludge  is,  the  more  treatment  is 
needed  to  pursue  recovery  over  disposal  and  partially  or  completely  remove  the  chemical 
pollutants as well as microplastics and antimicrobial resistance genes that may cause risks to 
human health and the environment (e.g. PAH, PCDD/F, long-chain PFAS) which also leads 
to  increases  in  costs,  and  most  likely  lowering  the  net  carbon  footprint  of  the  sludge 
management.  

Anaerobic digestion (AD) is a growing treatment method as it allows the production of biogas 
concomitantly with sludge use in agriculture: while the process generates biogas the resulting 
digestate  (a  more  concentrated,  dryer  and  stabilised  sludge)  can  be  used  on  land  as  organic 
fertiliser  in  parallel,  though  not  systematically,  e.g.  if  farmland  is  too  far  from  the  AD 
digester/UWWTP.117 While there is limited information on the quantities of sludge treated by 
anaerobic digestion across Member States, it is set to grow, also in view of the stakeholders 
consulted, in particular, in view of the EU targets for renewable energy and circular economy 
policies. The key limitation to AD treatment is heavy metals concentrations in sludge which 
are not decreased by the process and require further treatment. In certain cases such treatment 
may be rendered impossible due to technological feasibility to reduce contaminant levels, the 

114 Source: JRC policy report on the Urban Waste ater Treatment Directive  [not published yet at the time of writing] 
115 COM(2020)663 final of 14.10.2020. 
116 Huygens et al., 2022 
117 From Wood, Support to the evaluation of the Sewage Sludge Directive - Exploratory study [not published yet]: Anaerobic 
digestion  produces  digestate  and  traps  natural  gas  which  can  be  used  in  combined  heat  and  power  generation  or 
upgraded to methane for use in the grid or transport. 

43 

 
 
                                                 
availability of facilities for suitable treatment or other factors, in particular linked to storage 
and costs.118  

On the other hand, the policy directing sludge to incineration (or co-incineration which aims 
only at energy recovery) for heat production impedes the recovery of the organic nutrients in 
sludge.  Some  European  countries  follow  such  policies  that  discourage  the  application  of 
sludge  to  land  and/or  encouraging  P  recovery  from  different  feedstock,  including  sewage 
sludge.  This  has  led  to  an  increase  of  the  application  of  incineration  and  other  thermal 
treatment  techniques,  in  most  instances  followed  by  mineral-like  phosphorus  recovery 
methods  (from  the  ash  resulting  from  incineration).  The  P  recovery  technologies  applied 
following thermal treatment of sludge have the potential to recover between 85% and 99% of 
the  P  contained  in  the  sludge  and  also  the  potential  to  further  depollute  the  sewage  sludge 
waste  stream;  it  is  a  growing  trend  but  still  far  from  being  done  systematically.  P  recovery 
from sewage sludge ash is currently more expensive to implement and operate compared to 
the  revenues  generated  from  selling  fertilisers,  which  limits  the  potential  for  widespread 
implementation119.  This  treatment  route  does  not  allow  for  the  recovery  of  the  organic 
nitrogen  and  organic  matter  contained  in  the  sludge.  Nevertheless,  these  practices  do  not 
always  lead  to  diversion  from  the  use  of  sludge  in  agriculture,  since  this  may  be  the  most 
appropriate recovery operation if sludge is not suitable for land use in view of its content or 
soil quality or there are other obstacles to agriculture use (during winter months other uses of 
sludge are pursued as it can be complicated and costly to store sludge during that period). 

In  view  of  these  co-existing  policies  shaping  the  sludge  use  strategies,  it  is  necessary  to 
identify  the  relative  importance  of  sewage  sludge  to  different  sustainability  dimensions,  of 
which  soil  and  human  health,  resource  efficiency  in  waste  and  nutrient  management  and 
climate change are the most relevant ones120.  

Stakeholder views on coherence with EU policies overall 

Respondents to the OPC and to the targeted consultation of Member States and stakeholders 
broadly  agreed  that  the  SSD  is  coherent  with  the  Green  Deal.  Similar  patterns  of  responses 
were  provided  when  more  specifically  considering  the  coherence  of  the  SSD  with  the 
different deliverables of the Green Deal, albeit with some nuances: Member States tended to 
disagree that the SSD is coherent  with  the soil strategy, and targeted stakeholders tended to 
disagree regarding its coherence with the Farm-to-Fork strategy. Respondents from the OPC 
also  tended  to  agree  on  the  coherence  with  the  climate  objectives  and  in  particular  the 
methane strategy.  

Respondents’ awareness of the coherence of the SSD with other EU policies was rather low, 
with ‘I do not know’ answers averaging 38% across all the policies listed under the coherence 
question  (nonetheless,  specific  mentions  of  coherence  with  other  EU  policies  were  made  in 
several  open  questions  later  on).  According  to  the  respondents,  the  Urban  Waste  Water 
Treatment  Directive  is  the  most  coherent  EU  policy  with  the  SSD  (“Agree”  or  “Strongly 
agree” n=86 out of 173 respondents to this question: 50%). Respondents identifying as from 
the  wastewater  treatment  sector  agreed  more  than  they  disagreed.  121  It  is  followed  by  the 
Circular Economy Action Plan and the Nitrates Directive (“Agree” or “Strongly agree” n=61 

118 Wood, 2022.  Evaluation of the Sewage Sludge Directive – Exploratory study; Huygens et al., 2022 
119 Wood, 2022. Support to the evaluation of the Sewage Sludge Directive - Exploratory study 
120 Huygens et al., 2022 
121 30 out of 59 (50%) agreed or strongly agreed, while 11 (18%) disagreed or strongly disagreed. 

44 

 
 
                                                 
for both  out  of 171 and 170 respondents  to  this question:  36%). Respondents  identifying as 
farmers  agreed  more  than  they  disagreed  that  the  SSD  was  coherent  with  the  Nitrates 
Directive. 122 The lowest level of coherence was noted for the European Green Deal (n=56 out 
of 171 respondents to this question; 33%) and  

Stakeholder views on coherence with the Green Deal: 

From  the  171  respondents  to  the  OPC,  28%  agreed  that  the  SSD  is  coherent  with  the  EU 
Green Deal, while 33% disagreed and 12% were neutral123.  

MS  targeted  consultation  evidenced  that  33%  out  of  18  respondents  agreed  that  the  SSD  is 
coherent with the European Green Deal, 22% were neutral, 17% disagreed124.  

The targeted consultation with stakeholders evidenced that 44% out of 41 respondents agreed 
that the SSD is coherent with the European Green Deal, 7% were neutral, 30% disagreed.125  

Similar  patterns  of  responses  were  provided  when  more  specifically  considering  the 
coherence  of  the  SSD  with  the  different  deliverables  of  the  Green  Deal,  apart  from  the 
following: MS tended to disagree that the SSD is coherent with the soil strategy, and targeted 
stakeholders  tended  to  disagree  regarding  its  coherence  with  the  Farm-to-Fork  strategy. 
Respondents from the OPC also tended to agree on the coherence with the methane strategy. 

2.1.3.3.     Coherence with Union’s international obligations 

The  implementation  of  the  Directive  contributes  to  attaining  of  the  United  Nations 
Sustainable  Development  Goals:  SDG  6  on  clean  water  and  sanitation,  SDG  2  on  ending 
hunger,  achieving  food  security  and  improved  nutrition,  and  promoting  sustainable 
agriculture;  SDG  12  on  ensuring  sustainable  consumption  and  production  patterns.  Finally, 
the protection of soil and the limit values for heavy metals in the soil established by the SSD 
help  the  attainment  of  SDG  15  on  protecting,  restoring,  and  promoting  sustainable  use  of 
terrestrial  ecosystems,  sustainably  manage  forests,  combat  desertification,  and  halt  and 
reverse  land  degradation  and  halt  biodiversity  loss.  The  nutrient  recovery  dimension  of  the 
SSD  can  also  help  achieve  the  Land  Degradation  Neutrality  target  by  2030  set  by  the  UN 
Conference of Parties on Climate Change. Its goal is to protect, maintain, restore and enhance 
the  land  resource  base  necessary  to  support  ecosystem  functions  and  services  and  enhance 
food security. 

4.2  4.2.   EU added value 

Since  incorrect  application  of  sludge  on  soil,  in  particular,  in  view  of  its  contaminants  and 
amount  applied  on  soil,  may  result  in  soil  and  water  pollution  (eutrophication)  which  may 
have  transboundary  effects,  action  at  EU  level  is  justified  to  ensure  minimum  harmonised 
rules  for  environmental  protection  while  creating  and  continuing  to  encourage  nutrient 
recovery and avoid their loss. There is an ongoing need for the use of sludge in agriculture to 
be  regulated  in  order  to  ensure  that  it  is  carried  out  safely  and  without  harm  to  the 
environment.   

122 9 out of 20 (45%) agreed or strongly agreed, while 4 out of 20 (20%) disagreed or strongly disagreed. 
123 Others did not know/no opinion (27%). 
124 Others did not know/no opinion 
125 Others did not know/no opinion 

45 

 
 
                                                 
The  key  value  of  the  SSD  lies  in  its  establishment  of  minimum  level  of  harmonisation  for 
promoting  safe  use  of  sludge  on  farmland  across  the  EU,  which  complements  the  general 
rules of the Waste Framework Directive in relation to sewage sludge. Despite the fact that a 
large  number  of  Member  States  have  adopted  more  stringent  rules  than  the  SSD,  this 
minimum level of environmental protection rules provide the basis for the national regulations 
in other Member States and candidate countries and new neighbourhood countries, where the 
minimum standards in the Directive have not yet been attained. Important to note that neither 
the  literature  review  nor  stakeholder  consultation  revealed  any  significant  heavy  metal 
pollution  caused  by  the  use  of  sludge  on  farmland,  but  some  literature  sources  showed 
potential  content  of  contaminants  and  evidence  of  pollution  from  others.  There  is  also  no 
absolute commonalities in the way diverging Member States have addressed contaminants of 
emerging  concern.  This  suggests  that  a  level-playing  field  is  not  ensured  and  that  there  has 
been unequal protection of human health and the environment across the EU, which puts in 
question  whether  the  Directive  ensures  high  level  of  protection  of  the  environment  and  its 
added value on current sludge management policies and practices at national level. Also, the 
assessment referred to in section 3.1.1 of this report also indicates that the implementation of 
the  SSD  has  influenced  or  still  influences  the  management  practices  of  sewage  sludge  to  a 
limited extent. However, in view of the already existing large discrepancies in national rules, 
it can be argued that the inconsistencies may increase even further if the Directive were to be 
repealed. 

With regard to the value of the SSD in preventing barriers to the internal market, as assessed 
in  Section  3.1.3.1.  on  internal  coherence,  neither  the  design  of  the  SSD  in  view  of  its 
minimum harmonisation, nor its specific measures provide effective rules for that purpose, in 
particular, with regard to those Member States that have adopted stricter rules. Also, the new 
Fertilising  Product  Regulation,  adopted  in  2019  now  provides  a  more  effective  regulatory 
framework  ensuring  the  free  movement  of  sewage  sludge  derived  fertilisers  that  are  in  its 
scope. 

With regard to the Union’s objective to transition to a circular and sustainable economy, the 
SSD  is  a  policy  and  regulatory  tool  to  drive  the  return  of  nutrients  to  soil.  Its  added  value 
could,  however,  be  strengthened  by  attaining  full  harmonisation  in  view  of  ensuring  high 
level of environmental protection across the Union. Based on stakeholder feedback this would 
also improve the public perception which is a notable driver to sludge recovery in agriculture, 
in  particular,  in  view  of  the  increased  publicly  available  information  on  the  areas  where 
sludge is used as of 2023. 

During the public consultation, an overwhelming majority of respondents agreed that there is 
still  a  need  for  the  EU  to  regulate  the  use  of  sludge  in  the  agriculture  sector  (n=140  out  of 
176;  80%),  while  15%  of  the  respondents  (n=27)  said  that  it  should  only  do  so  for  some 
aspects. Explanations by the respondents pointed to the benefits of a uniform approach and a level-
playing  field  across  EU  MS  (n=16;  15%).  An  additional  10  respondents  (10%)  mentioned  the 
need for a further  harmonisation  of regulations  across MS. Other respondents  expressed the 
need  of  the  EU  to  regulate  sewage  sludge  to  protect  the  environment  (n=14;  13%)  and/or 
human  health,  including  in  terms  of  food  safety  (n=14;  13%).  Regulation  was  also  deemed 
beneficial  for  nutrient  recovery  (the  fertiliser  potential,  phosphorous,  nitrogen  and  organic 
matter  were  mentioned)  (n=9;  9%).  Another  theme  brought  up  was  the  need  to  extend  the 
SSD’s  scope  (include  new  pollutants  or  regulate  other  sludge  uses)  (n=15;  15%).  Other 
forward-looking  comments  were  submitted,  including  the  need  to  better  link  the  SSD  with 
other EU policies (n=11;  10%), including on fertilisers, circular economy, waste,  water and 
agriculture, and the need to improve monitoring (n=7; 7%). Conversely, a limited number of 

46 

 
 
respondents (two Swedish NGOs and one  Italian respondent; 3%) stated that sewage sludge 
should not be reused at all, or that the approach of the SSD should be changed significantly 
(only  allow  incineration  or  the  extraction  of  plant  nutrients  present  in  the  sludge)  (three 
Swedish respondents, including one company; 3%). 

4.3  4.3.   Relevance 

  Relevance of the Directive 

With  the  stability  or  increase  in  population  growth  and  with  the  increase  of  the  UWWTP 
networks and the level of treatment of wastewaters, safe management of sludge in line with 
the  waste  hierarchy  will  remain  necessary.  Today,  an  average  of  30-40%  of  the  sludge 
produced  in  the  EU  is  used  on  agricultural  land,  and  some  Member  States  such  as  Spain, 
Denmark, France,  Ireland, and Czech Republic use the large majority of their sludge in this 
way.  While  there  are  also  several  Member  States  that  discourage  the  use  of  sludge  in 
agriculture, there is also a trend to divert sludge from landfilling (a sludge management route 
used  for  10%  of  the  sludge  produced  in  the  EU)  which  may  benefit  the  agriculture  route. 
Therefore, the Directive has remained relevant over time, notably to pursue the objectives of 
the  circular  economy  to  ensure  compliance  with  the  waste  hierarchy  which  requires 
prioritisation of nutrient recovery over other recovery or disposal operations, also in line with 
the biomass cascading principle. 

The quantity of sewage sludge composted is expected to remain stable in the EU126. As seen 
in  section  4.1.3,  the  market  for  anaerobic  digestion  is  set  to  grow,  specifically  due  to  EU 
targets  for  renewable  energy  and  circular  economy  policies  and  because  it  is  a  treatment 
method  that  is  more  efficient  than  composting  for  pollutant  removal  even  if  it  does  not 
decrease the heavy metal concentrations (and of some other contaminants too, like PFAS). As 
regards the use of sludge on other types of land (e.g. landscaping, recultivation, tree nurseries, 
forestry), the trend is not clear as has not been assessed as part of this exercise. However, their 
use remains encouraged through the application of the general rules of the Waste Framework 
Directive which also prioritises the recovery of other biowaste.  

Some Member States are moving away from sludge reuse in agriculture to pursue objectives 
of energy recovery and/or phosphorus recovery through incineration. This emerging practice 
can be attractive, knowing that the planet’s phosphate rock reserves are finite (it is estimated 
that they will have been mined within the next 18 to 58 years), while the phosphorus-content 
in European sewage sludge could currently replace roughly 15% of the phosphate imports into 
the EU. This issue is gaining even more importance in the current context of the EU reducing 
its  dependency  on  imports  of  critical  raw  materials  such  as  phosphorus,  and,  recently, 
especially  imports  from  Russia:  currently  the  EU  imports  20%  of  its  phosphate  rock  from 
Russia. 

Also as seen in section 3.1.3, energy recovery from sewage sludge treatment is also set to gain 
attractiveness  to  help  achieve  energy  efficiency  goals  and  energy  autonomy,  whether  at  the 
EU  level  but  also  at  the  level  of  wastewater  treatment  plants.  The  trend  of  production  of 
biogas  is  also  set  to  grow:  according  to  the  EU’s  long-term  decarbonisation  strategy127,  by 
2050, the EU’s annual consumption of biogases (biogas and biomethane) is projected to grow 
to  between  54  and  72  Mtoe,  from  around  17  Mtoe  in  2017.  As  referred  to  in  the  previous 

126 Wood, 2022. Support to the evaluation of the Sewage Sludge Directive - Exploratory study  
127 COM(2020) 663 final of 14.10.2020. 

47 

 
 
                                                 
sections,  certain  treatments  of  sludge  may  serve  both  objectives  on  nutrient  and  energy 
recovery simultaneously.  

  The set of regulated contaminants require a review 

Regulating the heavy metals covered by the Directive remains relevant, as they still count as 
most  dangerous  substances  to  human  health  and  the  environment.  However,  despite  no 
evidence  pointing  to  pollution  of  soils  with  heavy  metals  due  to  use  of  sewage  sludge,  the 
varied  scope  of  regulated  contaminants  and  their  limit  values  across  the  Member  States 
question whether the SSD ensures a high level of protection of the environment and human 
health from the scientific point of view. This uncertainty impacts the trust in the Directive and 
the use of sludge on agriculture land by its stakeholders and also the public, which as of 2023 
will have access to spatial data on the specific areas where sludge is applied.  

Since  the  Directive  was  adopted,  Recommendations  of  the  World  Health  Organisation 
(WHO) and the European Food Safety Authority (EFSA) on safe intake levels of metals have 
substantially decreased. Furthermore, the approach taken by many Member States to set lower 
limits,  and  techno-scientific  progress  made  in  the  meantime  also  point  to  the  need  for  re-
examining these limits. It is also noted that limit values for heavy metals in the EU Fertilising 
Products Regulation ((EU) 2019/1009) are more stringent than the limit values laid down in 
the SSD.  

Over time a number of further contaminants have raised attention and should be examined, in 
particular,  in  view  of  the  proposal  for  a  revised  UWWTD  which  aims  to  address  pollution 
prevention at source and increase the treatment level of wastewaters and consequently change 
the  sludge  composition.  They  include  the  additional  contaminants  regulated  by  Member 
States (listed in section 2.1), including microbial parameters (against disease transmission), a 
need  confirmed  by  a  study  on  new  approaches  to  sludge  management128.  In  addition,  other 
contaminants of emerging concern would be opportune to assess in view of some regulation 
by Member States. There is no definition of “contaminants of emerging concern” as such, but 
among  those  are  pharmaceuticals,  PFAS  (known  as  ‘forever-chemicals’  as  they  are  very 
persistent in the environment) and microplastics. In parallel, some concerns have been raised 
as regards its possible effects on microbial resistance, and, with the outbreak of the COVID-
19 pandemic, its potential contribution to the dissemination of the virus. 

The  JRC  also  undertook  modelling  work129  which  identified  several  contaminants  in  sludge 
applied onto  agricultural land  which, under  “reasonable worse  case” scenarios, are likely to 
cause human health and environmental risks. These are, for instance, PFAS and PAH130. The 
pollutants associated to the greatest risks are already subject to actions and restrictions under 
the  POPs  and  REACH  Regulation.  Risk  mitigation  options  were  also  assessed:  they  may 
involve  limiting  the  concentration  of  pollutants  of  concern  in  sewage  sludge.  Biological 
sludge treatment options such as composting and anaerobic digestion, may not be effective to 
remove  the  persistent  pollutants  of  concern  to  below  levels  of  concern.  On  the  other  hand, 
incineration in modern plants has the potential to effectively lower pollutant levels to low or 
negligible  concentrations,  after  which  the  ashes  could  be  used  as  an  intermediate  in  P-
fertiliser manufacturing processes. (This is recognised in the Fertilising Products Regulation, 
for instance). An alternative risk mitigation option is to reduce the volumes of sewage sludge 

128 Mininni, G. et al (2015) 
129 European Commission, Joint Research Centre, Huygens et al, 2022 
130 Perfluoroalkyl substances (PFASs) and polycyclic aromatic hydrocarbons (PAHs) are used in many products e.g. clothing, 
furniture,  adhesives,  food  packaging,  non-stick  cooking  equipment.  They  became  of  concern  due  to  their  high 
persistence in the environment and their presence in wildlife and humans. 

48 

 
 
                                                 
spread on land relative to the modelling scenario of 5 tonnes dry matter ha-1 yr-1 applied in 
that JRC study. For instance, an application scenario with a maximum load of 2 tonnes of dry 
matter per ha every 3  years would already reduce pollutant loads by approximately a factor 
10.  Finally,  hybrid  options  could  be  envisaged  to  ensure  full  environmental  and  health 
protection from the effects of organic pollutants. 

Microplastics are an increasing source of concern. Microplastics adversely influence physical 
soil  properties  such  as  water  holding  capacity,  soil  aggregation,  the  performance  and 
composition of the soil microbial community and soil fauna131. They can adhere to the surface 
of  seeds  and  roots  and  can  be  taken  up  by  plants,  causing  negative  effects  (e.g.  oxidative 
stress,  cytotoxicity,  and  genotoxicity132).  Research  efforts  on  the  contamination  of  the 
environment by microplastics and its consequences are being scaled up, but at present there is 
little knowledge on the magnitude of adverse effects133. 

A  pilot  study  recently  undertaken  by  the  JRC  estimates  that  about  60  microplastic  particles 
could  be  present  in  a  gram  of  cultivated  soil  (from  50  samples  collected  across  7  Member 
States).  Work  is  ongoing  to  identify  whether  sewage  sludge  was  applied  to  the  locations 
sampled.  Sludge  application  in  agriculture  has  been  correlated  with  increasing  quantities  of 
microplastics  in  exposed  soil134  and  it  is  assessed  that  in  countries  with  high  sludge 
application rates, the level of microplastics accumulated in the treated soils is expected to be 
higher  than  in  countries  with  lower  application  intensity.135  Evidence  suggests  that  regular 
application of microplastics leads to significant accumulation in soils, and that sewage sludge 
is one of the main entry routes for microplastics into the terrestrial environment136. Between 
360  and  1980  tons  microplastics  could  reach  municipal  wastewater  treatment  plants  every 
year  in  the  EU137,  and  after  treatment  of  the  wastewater  in  wastewater  treatment  plants,  the 
majority  of  microplastic  particles  become  entrained  in  sewage  sludge138.  The  extent  of  the 
problem  is  yet  to  be  thoroughly  assessed  but  it  is  expected  to  increase  with  the 
implementation    of  the  revised  UWWTD.  Lofty  et  al.  (2022)  estimate  that  sewage  sludge 
applications on agricultural land introduce between 31 000 and 42 000 tonnes of microplastics 
(or 86–710 trillion microplastic particles) to European soils annually. 

The  fate  of  microplastics  in  the  soil  and  their  effect  on  human  health  (through  ingesting  of 
crops grown on soil where sludge has been applied, or irrigated with contaminated water) are 
still  debated  and  will  require  further  study  before  the  full  implications  are  known139.  The 
Horizon  2020  EU  Research  and  innovation  Framework  Programme  has  funded  research  on 
this  subject.  Its  successor,  Horizon  Europe,  (2021-2027)  envisages  related  activities  under 
Cluster  6  “Food,  Bioeconomy,  Natural  Resources,  Agriculture  and  Environment”  and  the 
Horizon Europe Mission ‘A Soil Deal for Europe’. The contribution of sludge application to 
the  presence  of  microplastics  on  agricultural  land,  in  comparison  to  other  agricultural 

131 Büks and Kaupenjohann, 2020 
132 Li et al., 2020; Azeem et al., 2021; Mateos-Cárdenas et al., 2021; Wang et al., 2022 
133 Büks and Kaupenjohann, 2020 
134 Nizzetto et al, 2016. 
135 Hurley, R., & Nizzetto, L., 2018 
136 Büks and Kaupenjohann, 2020; van den Berg et al., 2020; Azeem et al., 2021; UNEP, 2022 
137 Nizzeto et al.,  
138 As much as 98% of the total influent load according to a study by the Irish EPA, 2017: Mahon, A.et al, 2017. 
139 Campanale et al., 2020 

49 

 
 
                                                 
practices  (e.g.  poly-tunnels,  mulching  substances,  baled  silage,  with  debris  gradually 
degrading into smaller pieces), should also be investigated. 

Research  is  also  on-going  on  the  impact  of  antimicrobial  resistance  (AMR)  in  sludge  being 
applied to land, to better understand the risks that AMR poses to the environment140 but also 
the  role  that  sludge  treatment  could  play  in  limiting  those  risks.  The  World  Health 
Organization  (WHO)  has  identified  the  spread  of  antibiotic  resistance  as  one  of  the  major 
risks to global public health. AMR is estimated to be responsible for about 33,000 deaths per 
year in the EU.141 A study found that the long-term application of sewage sludge significantly 
increased  the  abundance  and  diversity  of  antibiotic  resistance  genes  in  the  soil.142  Sludge 
treatment  (hygienisation, e.g. liming, digestion, composting) can mitigate the effect,  but  not 
fully. However, it should be underlined that the contribution of sewage sludge to AMR when 
applied on agricultural  land is  likely smaller compared to  manure, which is  spread in  much 
larger quantities and mostly without prior hygienisation treatment143. 

There is also attention to pathogens which sludge could potentially convey, and the COVID-
19  pandemic,  has  raised  concern  around  the  dissemination  of  the  SARS-CoV-2  virus.  The 
latter  has  been  identified  in  wastewater144  and  primary  sludge  samples145.  The  Commission 
has recommended  a common approach to  establish systematic surveillance of SARS-CoV-2 
in  wastewater.  Wastewater  monitoring  for  early  warning  and  tracking  of  disease  outbreaks 
seems  likely  to  continue,  given  its  potential  for  widespread  coverage  and  relatively  low 
cost).146 However, the search for SARS-CoV-2 RNA alone is not sufficient to determine any 
risk  situations  due  to  the  spreading  of  the  sludge  on  the  soil.147  Since  transmission  occurs 
through the respiratory tract, the concerns mainly relate to exposure to droplets and dust that 
could be emitted during sludge application. ANSES (Agence nationale (française) de sécurité 
sanitaire  de  l’alimentation,  de  l’environnement  et  du  travail)  also  indicated  that  the  risk  of 
SARS-CoV-2  contamination  could  be  considered  negligible  if  sludge  has  undergone  a 
disinfection  process  according  with  the  regulations  and  provided  recommendations  to 
reinforce controls on treatment processes148. ANSES therefore recommend that such sewage 
sludge should not be applied to land without first being disinfected. However, they also note 
that data on the inactivation of SARS-CoV-2 in sludge and effluent are still incomplete and 
very  little  information  is  available  to  precisely  define  the  level  of  contamination  by  SARS-
CoV-2 in sludge that has not undergone some sort of disinfection treatment. Further work will 
therefore  be  necessary  before  a  consensus  is  reached  on  the  most  appropriate  treatment  to 
ensure that the risk of SARS-CoV-2 contamination in sludge is low. 

140  This  is  notably  in  the  context  of  the  ERANET  co-funded  action  AquaticPollutants,  http://www.waterjpi.eu/joint-

calls/joint-call-2020-aquaticpollutants 

141 European Commission - EU Action on Antimicrobial Resistance: https://ec.europa.eu/health/antimicrobial-resistance/eu-
action-on-antimicrobial-resistance_en  
142 Qinglin et al. (2016). 
143 Also knowing that within the EU, the consumption of antimicrobial substances is approximately equally divided between 

uses for food-producing animals and humans (EMA/ECDC/EFSA, 2021) 

144 Larsen, D.A. (2020) 
145 Peccia et al. (2020). 
146 EUR 25 000 for one WWTP per year. https://op.europa.eu/en/publication-detail/-/publication/816cec6d-abbd-11eb-927e-

01aa75ed71a1/language-en JRC, 2021 

147 Gianico et al. 
148 ANSES (2020, April 2) 

50 

 
 
                                                 
As  knowledge  of  contaminants  and  treatment  technology  evolves,  there  is  need  for  more 
systematic assessment  of the relevance and appropriateness  of the set  of  pollutants covered. 
Stakeholders identified the relevance of sewage sludge in  the transition  towards the circular 
economy and its content in substances of concern in sewage sludge as main topics of interest. 
Stakeholders  also  voiced  the  need  to  reassess  the  list  of  contaminants  during  the  public 
consultation. 

The issue of emerging pollutants is not one that is isolated from the SSD and will also need to 
be considered in the context of other ongoing revisions of other EU legislation, including the 
development  of  a  new  legislative  initiative  on  healthy  soils  announced  in  the  EU  Soil 
Strategy.  The  SSD  may  need  to  be  flexible  to  respond  to  such  changes.  For  instance,  the 
review of the UWWTD may result in a higher loads of nutrients in sludge, and, is also likely 
to  raise  the  contaminants  content  of  that  sludge.  This  will  challenge  the  re-use  (i.e.  direct 
application on land) of sludge, and result in the need for more advanced sludge treatment for a 
safe application, which implies more costs and carbon footprint. 

In terms of the methodology to assessing the enlargement of scope of regulated contaminants, 
a  JRC  study149  has  highlighted  the  importance  of  the  distinction  between  “risk  v  hazard” 
approaches. Numerous studies have reported the presence of organic compounds, pathogens, 
pharmaceuticals,  and nanomaterials  in  sewage sludge,  albeit  many of them  note that further 
evidence is needed to fully understand how they behave when sludge is reused in agriculture 
and the likelihood of  accumulation in  soil to  levels  which may pose a risk to human health 
and the environment150. Thorough risk assessments should be conducted as appropriate, also 
taking into account of the contribution of sludge to the presence of these contaminants in the 
environment,  compared  to  other  sources.  Most  persistent  and  bioaccumulative  organic 
contaminants would deserve focus151, as confirmed by findings from that study, and previous 
work152,153.  Note  that  these  pollutants  may  also  be  regulated  in  the  near  future  through  on-
going initiatives under the umbrella of the Chemicals Strategy for Sustainability, ZPAP and 
Soil Strategy. 

During the expert interviews conducted during the public consultation, half of the respondents 
(n=26 out of 52 respondents to this question) answered the open question on the added value 
of  EU  intervention  in  a  forward-looking  manner,  pointing  to  the  view  shared  by  many 
respondents throughout previous questions that the SSD needs to be updated. 

  Suitability of a stand-alone instrument / Opportunities for simplification 

The  SSD  has  been  set  as  a  self-standing  instrument  to  regulate  the  very  specific  issue  of 
sewage  sludge  used  on  agricultural  soil.  In  line  with  the  objectives  of  the  EU  Better 
Regulation  agenda  to  simplify  and  improve  EU  law,  consideration  should  be  given  to  a 
possible repeal of the Directive and/or integration of its rules into related legislation.  

149 Huygens et al, 2022 
150 For instance, there is limited understanding of the behaviours of contaminants of emerging concern in sludge. A study of 
sludge from 11 WWTPs in the UK suggested that pharmaceutical residues in sludge should not lead to concentrations of 
concern in soils (UKWIR, 2018b). 

151 Huygens D. et al, 2022 
152 Norwegian Committee for Food Safety, 2009; Rigby et al., 2021; Smith, 2009 
153 Huygens et al, 2022 

51 

 
 
                                                 
In  view  of  the  continued  relevance  of  the  regulation,  a  full  repeal  is  not  considered 
appropriate.  In  terms  of  possible  simplification  which  would  maintain  or  strengthen  
coherence  with  other  Union  legislation,  the  potential  to  exploit  synergies  with  other 
legislative instruments that have close links with the SSD could be explored: 

(1) other  waste  legislation  which  regulate  recovery  and  safe  management  of  waste, 

notably the Waste Framework Directive; 

(2) the Soil Health Law envisaged in the EU Soil Strategy for 2030154. Synergies could be 
explored in relation to the definition of soil health, the soil monitoring provisions (e.g. 
for certain soil pollutants) and the requirements on sustainable soil management.  

(3) water  protection  related  legislation,  e.g.  the  UWWTD155.  This  would  offer  the 
possibility of streamlining reporting requirements to an extent, as discussed in section 
1.1.3.3.  It  might  be  possible  to  cover  the  whole  lifecycle  of  the  wastewater  from 
production  to  treatment  and  use  of  the  outputs  of  that  process,  also  exploiting  links 
between treatment strategies at the UWWTP and further use of sludge. 

There  are  direct  links  between  designing  and  operating  of  the  wastewater  treatment 
plant and sludge management strategies to opt for, notably in terms of sludge quality 
and treatment facilities. Sludge management constitutes a significant share of the cost 
of wastewater treatment. Closer cooperation between those producing and treating the 
sludge and those using the sludge for agricultural or other purposed could be sought. 
Real-time  monitoring  of  sludge  quality  at  the  treatment  plant  could  be  sought  too. 
More  generally,  this  would  facilitate  the  streamlining  of  monitoring  and  reporting 
requirements  between  the  SSD  and  the  UWWTD.  The  part  of  the  monitoring  and 
reporting  requirements  of  the  Directive  which  relates  to  sludge  quality  could  be 
covered under the UWWTD in a more holistic way. This could also allow the choice 
of  sludge  management  options  to  be  considered  in  strategies  aiming  at  energy 
efficiency and autonomy in energy supply at the wastewater treatment plants, known 
to be very energy demanding. In addition, the recovery of valuable raw materials such 
as phosphorus, as already proposed in the revised UWWTD, could be further targeted 
in line with the needs of society.  

(4) The Fertilising Products Regulation, as a vehicle for EU-wide end-of-waste criteria for 
certain sludge derived materials in EU fertilising products, where safety of such sludge 
derived materials is confirmed. 

Stakeholders involved in the targeted consultation and Member States tend to agree that the 
SSD  is  still  relevant.  They  also  supported  the  benefits  and  opportunities  for  further  policy 
integration  and  simplification  by  integrating  SSD  rules  into  the  UWWTD.  Notably  among 
Member States,  37% (of 19) responded that it should  be integrated into the UWWTD;  32% 
reporting it was still relevant as a standalone instrument; 16% reporting it should be integrated 
into another legislative instrument. Of 44 responses to the targeted consultation, 50% thought 
that it is still relevant as a standalone instrument, 9% responded that it should be integrated 
into  the  UWWTD,  18%  responded  that  it  should  be  integrated  into  another  legislative 
instrument.  

154The  Call  for  Evidence  for  the  initiative  available  here:  https://ec.europa.eu/info/law/better-regulation/have-your-

say/initiatives/13350-Soil-health-protecting-sustainably-managing-and-restoring-EU-soils_en 

155  While  the  on-going  review  of  UWWTD  is  not  designed  to  take  over  sewage  sludge  use  regulatory  framework,  it  still 

presents an option in the future.  

52 

 
 
                                                 
5 

5. 

WHAT ARE THE CONCLUSIONS AND LESSONS LEARNED? 

5.1  5.1. Conclusions 

2.1.4. 

5.1.1. Effectiveness 

The use of sludge in  agriculture has remained the main route for sludge management in the 
EU  since  the  evaluation  which  had  been  carried  out  for  the  SSD  in  2014.  For  the  EU  as  a 
whole, the total percentage of sewage sludge used in agriculture falls between 30% and 50% 
of the total sewage sludge produced, amounting to 2-3 out of 7-8 mio tons/yr. When sludge is 
not used in that way, it is incinerated (this use coming closely second, 27%), composted (not 
known,  but  estimated  to  be  10%),  or  landfilled  (currently  11%,  but  this  practice  is  phasing 
out). Overall, sludge production has been rather stable in the EU over 2007-2018, and so has 
the  share  of  sludge  used  in  agriculture.  Sludge  has  been  widely  and  steadily  used  to  the 
benefit of agriculture, leading to the recovery of nutrients from 2 to 3 million tons of sludge 
per year, while also enhancing the soil structure, for the benefit and sustainability of the waste 
and agricultural sectors.  

The decrease of the level  of heavy metals  in  sewage sludge since the SSD came into force, 
can be attributed to an extent to the effect of the Directive, butit is difficult to single out its 
actual  contribution:  here.  Many  Member  States  have  adopted  more  stringent  requirements, 
which  makes  it  challenging  to  distinguish  the  effects  of  the  SSD  from  national  action. 
Legislation regulating pollution at the source can have had an effect too. 

Limited information was identified linking overall agricultural soil quality and use of sewage 
sludge, in particular on potential effects of long-term of sludge application, and on the share 
of  the  impacts  of  sewage  sludge  compared  to  other  activities  that  have  an  impact  on  soil 
quality, e.g. fertiliser, manure, background pollution. Research is going on into possible long-
term impacts of sewage sludge use in agricultural land on soil quality.  

A range of other factors have contributed to achieving the objectives of the Directive. First, a 
number  of  voluntary  schemes  of  quality  standards  have  been  set  up  between  stakeholders, 
increasing trust in sludge quality. Secondly, the availability of sludge of relevant quality and 
its  benefits  on  soil  quality,  including  organic  matter  content,    and  water  retention  capacity 
have  promoted  the  use  in  agriculture  too.  In  addition,  the  implementation  of  the  Waste 
Framework  Directive,  Landfill  Directive  and  the  inclusion  of  some  materials  derived  from 
sludge156 into the Fertilising Products Regulation also contribute to the recovery of waste over 
final disposal. 

Conversely, the objectives of the Directive have been hindered by a number of factors, which 
include the public perception of risks associated with sewage sludge, the lack of harmonised 
end-of-waste  criteria  for  sewage  sludge  to  be  applied  onto  land,  the  competition  for 
agricultural use with other organic waste (e.g. manure or biowaste), and the competition with 
other uses of sludge (e.g. for land reclamation, remediation or landscaping). 

The  Directive  also  has  had  other  positive  effects:  interest  and  knowledge  in  sewage  sludge 
and its management techniques have increased, as shown for instance by the large number of 
research  projects  for  the  treatment  of  sewage  sludge  with  recovery  of  nutrients  or 

156 Precipitated phosphate salts, high purity salts and ashes 

53 

 
 
                                                 
transforming into other applications. Application of sludge onto farmland also seems to have 
an overall negative carbon footprint. 

Negative  unintended  effects  from  its  implementation  include  the  presence  of  antimicrobial 
genes  and  microplastics  in  the  soil,  possible  emissions  of  ammonia,  methane  and  nitrous 
oxide, as well as of other contaminants which it can contain and which are not regulated by 
the Directive. Research is on-going to determine their fate and effect, and assess whether and 
to  which  extent  those  elements  do  actually  pose  a  risk  to  the  environment  and  the  human 
health.  

Overall,  the  assessment  of  the  effectiveness  was  rendered  challenging  by  data  gaps  and  
inconsistencies,  including  data  reported  under  the  Sewage  Sludge  Directive,  the  Urban 
Wastewater  Treatment  Directive  and  Eurostat.  This  results  from  unclarity  in  certain 
definitions and coherence between the reporting obligations across the two directives.  

2.1.5. 

5.1.2. Efficiency 

The  use  of  sludge  in  agriculture  entails  significant  costs,  notably  linked  to  treatment  and 
transport. Treatment is required to make it suitable for use on land, for reasons of safety (e.g. 
pathogen removal, hygienisation) or for transport since treatment allows to reduce the volume 
and weight of sludge, facilitating its transport.  

It  is  very  difficult  to  estimate  the  overall  costs  and  benefits  of  the  implementation  of  the 
Directive,  notably  because  of  the  lack  of  data  on  the  different  treatment  pathways  and 
combination  thereof,  and  the  lack  of  data  on  externalities.  However,  it  appears  that  the 
application of sludge to agricultural land is significantly less costly than other options for use 
of sewage sludge. 

This is particularly true in comparison with (mono-)incineration, which is the main alternative 
to  the  use  of  sludge  in  agriculture.  If  a  hypothetical  shift  from  the  current  sludge  volumes 
from agriculture towards incineration were to occur, it was estimated that this would result in 
an additional cost of EUR 41–488 million per year, depending on the incineration technology 
assumed. For mono-incineration these additional costs would be of EUR 391-488 mio/yr 157 

Administrative  costs  have  been  estimated  to  be  around  EUR  77,000-80,000  per  year  per 
Member  State  and  appear  as  quite  moderate  in  comparison  with  other  EU  environmental 
legislation.  These  costs  will  also  slightly  increase  with  new  reporting  obligations  on  spatial 
data of sewage use. Reporting has shown rather insufficient and not well respected. 

The  use  of  sewage  sludge  compared  to  mineral  fertilisers  (i.e.,  chemically  produced)  could 
also  allow  savings  to  farmers.  As  an  order  of  magnitude,  it  was  calculated,  in  a  theoretical 
case  where  sludge  would  fully  substitute  a  mineral  fertiliser,  that  they  could  be  up  to  some 
EUR 96/tDS for Nitrogen and EUR 44/tDS for Phosphorus. 

Also, given the high dependency of sludge management policies to local conditions, and the 
heterogeneity  of  such  conditions  across  Member  States  and  regions  or  municipalities,  the 
enabling  rather  than  prescriptive  nature  of  the  Directive  has  provided  a  framing  which  has 
allowed, in principle, for efficient decision-making at national and regional level. In view of 

157 Egle et al., 2023 (under development) 

54 

 
 
                                                 
this,  the  Directive  is  considered  to  be  cost-efficient,  in  particular,  as  sludge  treatment  is  a 
necessity for any kind of use or disposal of sludge.  

The uncertainty on costs and benefits is acute for externalities, where very few data could be 
provided. However,  these  should be seen in  comparison  of  agriculture use and other sludge 
management  routes,  as  they  remain  very  costly  (several  hundreds  EUR  tDS  all  costs 
considered on average) and entail similar externalities than the agriculture pathway 

2.1.6. 

5.1.3. Coherence 

The  legal  basis  of  the  Directive  is  now  outdated  in  view  of  its  content,  not  cross-border  in 
nature,  and  developments  of  the  EU  acquis  since  its  adoption:  a  specific  legal  base  for  the 
policies aiming to attain a high level of protection for the environment has been introduced.  

Some  of  its  definitions  and  rules,  like  that  of  sewage  sludge  and  of  treatment,  as  well  as 
reporting granularity provide scope for more clarity, in particular in view of increasing legal 
certainty and the level of protection on the environment. 

It  complements the Waste Framework Directive: encouraging sludge use in agriculture is in 
line  with  the  waste  hierarchy  set  out  in  the  latter,  where  recovery  of  nutrients  takes 
precedence over energy recovery and disposal. Resource efficiency in nutrient recovery also 
contributes  to  the  EU  objectives  of  increasing  independence  from  imports  of  mineral 
fertilisers, some of which are identified as critical raw materials for the EU economy. 

The  objectives  of  the  Directive  are  consistent  with  other  environmental-media  specific 
legislation, e.g. on water and air.  However, in terms of operational regulatory  measures this 
coherence  could  be strengthened if it were adapted to  techno-scientific progress,  notably  on 
the set of pollutants which it regulates. This would strengthen its coherence with the EU Soil 
Strategy for 2030, and, more generally, the Zero Pollution Action Plan. 

Several  legal  initiatives  relevant  to  sludge  management  are  on-going:  a  proposal  for  a  Soil 
Health  Law, revisions of the UWWTD and other water-related directives, and  of the Waste 
Framework Directive. The coherence of the SSD would need to be reassessed in view of such 
future  developments.  There  is  scope  for  further  clarifying  links  between  the  SSD  and 
UWWTD,  notably  aligning  the  analytical  methods  and  reporting  cycles  of  the  SSD  and 
UWWTD. Considering the Commission proposal for a revised UWWTD put forward on 26th 
October  2022,  the  revised  UWWTD  could  affect  the  composition  of  sludge  (notably 
potentially  increasing  its  concentration  in  microplastics,  but,  on  the  other  hand,  having  a 
positive effect on the level of contaminants which the UWWTD would reduce at the source, 
before the effluent enters the UWWTP) and possibly influence choices for treatment in view 
of energy efficiency. 

The wider policy framework has considerably evolved over recent years, notably as set by the 
Green  Deal  and  its  deliverables.  The  Directive  lies  at  the  core  of  these  ambitions  and  it  is 
found coherent with the European Green Deal and EU policies on climate neutrality, circular 
economy, bioeconomy and nutrient and energy independence. Pursuing these objectives may 
influence national sludge management policies differently, depending on local conditions e.g. 
the  agronomic  needs  for  soils,  energy  mix  and  available  infrastructure,  among  many  other 
drivers  for  decision-making  on  sludge  management.  This  can  influence  sludge  management 
strategies  or  specific  treatments  (e.g.  anaerobic  digestion),  with  varying  impacts  on  climate 
change  mitigation.  Higher  levels  of  treatment,  which  may  be  required  to  abate  the 
contaminants  present  in sludge before it can  be applied on land, are usually  associated with 

55 

 
 
higher  costs  and  a  larger  carbon  footprint.  Anaerobic  digestion  comes  across  as  a  very 
interesting  option,  as  it  allows  producing  biogas  while  treating  sludge,  but  it  is  not  always 
sufficient to remove certain pollutants. Treatment may not always be feasible, depending on 
the  availability  of  treatment  facilities,  but  also  technically,  depending  on  the  type  of 
contaminants  to  be  abated  in  the  sludge.  In  such  cases,  (mono-)incineration  could  be  a  last 
recourse, and electricity and heat can also be recovered from a renewable resource. 

2.1.7. 

5.1.4. EU added value 

The SSD has maintained its added value, as the sole legal instrument providing an EU wide 
framework  for  the  environmental  conditions  on  soil  protection  for  safe  use  of  sludge  on 
agricultural  land in  the EU, through setting  a minimum level  of harmonisation  for pollution 
control  and  reducing  environmental  and  health  risks  linked  to  the  recovery  of  sludge  in 
agriculture. 

Despite Member States having adopted more stringent rules than the SSD, this minimum level 
of  environmental  protection  rules  provide  the  basis  for  the  national  regulations  in  other 
Member  States,  candidate  countries  and  neighbourhood  countries,  where  the  minimum 
standards in the Directive have not yet been attained. Whilst the provisions of the Directive on 
limit  values  for  heavy  metals  cannot  be  said  to  be  obsolete,  since  they  set  an  important 
baseline,  the  fact  that  many  Member  States  have  set  stricter  limit  values  means  that  the 
Directive is not the sole driver for limiting the heavy metal content of soils and sludge.  

Also, the Directive promotes a main inexpensive sludge management route, which turns out 
as  a  cost-efficient  option  for  wastewater  operators,  while  allowing  savings  to  the  farming 
community on fertiliser use and reducing nutrient losses without deterioration in soil fertility 
and fertiliser use. 

2.1.8. 

5.1.5. Relevance 

Overall, the purpose and the regulations of the SSD continue to be relevant and supported by 
the  stakeholders.  While  the  heavy  metals  currently  regulated  do  not  appear  to  be  obsolete, 
limits would need review due to the age of the Directive and societal and analytical changes 
that have occurred since its implementation, since most Member States regulate several other 
substances going beyond the Directive (e.g. PCB, PAH, PCDD/F).  

As to other substances, numerous studies have reported the presence of organic compounds, 
pathogens, pharmaceuticals, nanomaterials and microplastics in sewage sludge, albeit many of 
them  note  that  exact  concentrations  require  further  monitoring.  The  set  of  contaminants 
regulated by the SSD would need review in  this regard.  Further  evidence is  needed to  fully 
understand  how  these  chemicals  behave  when  sludge  is  reused  in  agriculture  and  the 
likelihood of accumulation in  soil to  levels  which may  pose  a risk to  human health and the 
environment. Research would be needed on possible cocktail effects with contaminants from 
other sources too.  

5.2  5.2. Lessons learned 

The  objective  of  the  Sewage  Sludge  Directive  to  encourage  nutrient  recovery    is  consistent 
with  the  Circular  Economy  Action  Plan  under  the  umbrella  of  the  Green  Deal.  Nutrient 
recovery  is  also  paramount  to  attain  the  EU  policy  objectives  of  strategic  autonomy  in 
fertilisers and in securing food supply. Certain technologies such as anaerobic digestion also 
allow to make sludge more suitable for use in agriculture while producing biogas, which can 

56 

 
 
also  help  achieve  the  Union’s  objectives  of  energy  efficiency  and  independence  in  energy 
supply. 

Though the added value of the Directive could be challenged for those Member States having 
set  much stricter requirements or taken policy  choices such as banning  the use of sludge in 
agriculture,  it  offers  a  minimum  level  of  environmental  protection  rules  for  the  Union  as  a 
whole.  In  principle,  with  its  objective  of  environmental  protection,  the  SSD  would  be 
coherent with the Zero Pollution Action Plan and the Soil Strategy, but in practical terms the 
risks  linked  to  contaminants  need  to  be  reassessed.  In  the  framework  of  the  technical 
adaptation of the Directive to ensure that it pursues a high level of environmental protection, 
it  is  necessary  to  consider  recent  and  upcoming  research  and  monitoring  of  pollutants  in 
sludge  and  soil    and  review  the  set  of  pollutants  to  be  regulated.  This  would  require 
identifying potential contaminants to be covered. After assessment of their impact on the soil 
and  human  health,  possible  risk  management  measures  should  be  investigated  e.g. 
concentration  limits,  treatment  or  application  protocols  (amounts  over  several  years, 
application  at  certain  periods  of  the  year  etc).  Account  should  also  be  taken  of  the 
contribution  of sewage sludge to the levels  of such contaminants in  soil,  compared to  other 
sources, information that is currently lacking. 

Currently,  there  lacks  data  on  the  impact  of  sludge  application  on  land  on  the  environment 
and  the  human  health.  There  is  no  systematic  and  periodic  evaluation  of  the  environmental 
and health risks from sewage sludge management routes, neither at EU level nor consistently 
within the Member States. Partly, this is an indirect consequence of the lack of sludge quality 
monitoring  data.  Yet,  recommendations  and  limit  values  for  the  dietary  intake  of  certain 
contaminants  present  in sewage sludge have for  instance been revised at  repeated occasions 
during  the  last  decades  (by  the  WHO  or  EFSA).  At  the  same  time,  external  factors  have 
reduced  other  pressures  to  sustainable  sludge  management  (e.g.  the  outphasing  of  certain 
contaminants).  This  points  to  the  need  for  systematic  and  periodic  evaluation  of  health  and 
environmental  risks  from  sewage  sludge  management  to  maintain  the  relevance  of  the 
legislation over time. 

The  Directive  does  not  deliver  data  to  assess  the  impact  of  sludge  application  on  land  and 
make  sure  that  its  objectives  are  met.  The  current  reporting  system  shows  room  for 
improvement  in  a  number  of  ways.  It  does  not  allow  to  check  that  sludge  is  spread  in 
accordance with plant needs, which could result in a sub-optimal use of the sludge or excess 
of nutrients, possibly resulting in pollution of the groundwater. It is also unknown if sludge is 
applied outside periods of plant growth, as e.g. data on the temporary storage of sludge and 
capacities are missing. 

Compliance  with  the  existing  reporting  requirements,  e.g.  on  sludge  use  and  sludge  quality 
could  also  be  improved.  There  is  also  potential  for  simplification  and  improvement  of  data 
collection by rationalising the reporting requirements under the SSD, the Urban Wastewater 
Treatment Directive and Eurostat. 

The SSD also has to be seen in the wider context of sustainable development, zero pollution, 
energy efficiency, climate change, and EU policies aiming at reducing dependency to energy 
and critical raw materials, as there may be synergies and/or trade-offs between these different 
drivers  for  sludge  management  policies  or  practices.  Depending  on  local  settings  and 
priorities, specific sludge management routes or methods of treatment could be favoured. For 
instance, anaerobic digestion allows to produce biogas and renewable energy, while providing 

57 

 
 
benefits to farmers when the digestate can be used as a value-added material on agricultural 
land. 

Wide  differences  in  implementation  across  the  EU  were  observed.  They  can  be  explained 
partly  by  the  fact  that  the  set  of  pollutants  regulated  by  the  Directive  is  not  up  to  date,  by 
general  policy  choices  by  Member  States,  but  also,  to  a  large  extent,  by  the  fact  that  the 
choice for a given sludge management option strongly depends on local conditions. Overall, 
the  application  of  a  mix  of  established  and  innovative  techniques,  as  a  function  of  local 
settings  and  needs,  may  help  to  maximise  benefits  and  minimise  adverse  impacts  on  the 
different sustainability dimensions affected by sludge management within the EU. Therefore, 
maintaining the flexibility for the Member States and the economic operators to have choice 
for sludge management policies is important. It could be explored whether more guidance or 
instructions on treatment at EU level would have added value, for optimised benefits in terms 
of  nutrient  recovery  (and,  possibly,  energy  recovery  through  biofuel  production)  while 
securing protection of health and the environment.  

In  view  of  the  activities  envisaged  in  the  Union  Soil  Strategy  and  work  on  improving  the 
monitoring  framework  on  the  soil  health,  sludge  application  onto  land  outside  agriculture 
could  be  examined  too,  in  terms  of  risks  of  soil  contamination  on  the  one  hand,  and 
enhancement  of  soil  properties  and  supply  in  nutrients  on  the  other  hand.  Whether  for 
agriculture or other uses, it could then be explored whether the potential of sludge for nutrient 
recovery should be better exploited, through more incentives for such use. 
Certain elements of relevance for sewage sludge management will emerge from the evolution 
of the regulatory context, notably the revision of the Urban Wastewater Treatment Directive 
and  from  the  new  Soil  Health  Law,  in  parallel  to  development  and  effects  of  legislation 
reducing pollution at its source. The Directive can currently be seen as Lex specialis of the EU 
waste legislation. In view of seeking synergies and regulatory simplification, there will be a 
potential to exploit synergies with future waste, soil or water protection legislation. 

This should also provide the opportunity to adapt the legal base of the Directive or instrument 
which would regulate sewage sludge use in  agriculture to the current Treaty rules reflecting 
the main purpose of the measures therein. The current internal market legal base is outdated. 

This evaluation also broadly confirms the main conclusions of the 2014 evaluation, referred to 
in Annex VII, in relation to the effectiveness, efficiency, coherence and relevance criteria (the 
2014 evaluation did not look into the added value of the Directive). This evaluation allowed 
to gather more up-to-date information on the cost-efficiency of its provisions and reflections 
on  the  changed  policy  and  legislative  landscape  while  maintaining  the  key  substantive 
conclusions along the lines of the 2014 evaluation. 

58 

 
 
 
 
 
 
ANNEX I. PROCEDURAL INFORMATION 

LEAD DG: DG Environment 

DECIDE/AGENDA PLANNING REFERENCE: PLAN/2020/7406 

CWP  REFERENCE:  Commission  work  programme  (its  annex)  for  2021  (published  in 
November 2020) 

1. 

Derogations granted and justification 

No exceptions were made to the Better Regulation Guidelines during this Evaluation. 

2. 

Organisation and timing 

The  joint  inter-service  group  created  in  2017  for  the  Evaluation  of  the  Urban  Wastewater 
Treatment  directive  (UWWTD)  and  the  Fitness  Check  of  directives  related  to  water  also 
steered  the  work  on  this  evaluation.  It  is  set  up  with  representatives  from  the  following 
Directorate Generals: 

• Secretariat General (SG) 
• Legal Service (SJ) 
• Agriculture and Rural Development (AGRI) 
• Climate Action (CLIMA) 
• Communications Network, Content and Technology (CNECT) 
• Economic and Financial Affairs (ECFIN) 
• Environment (ENV) 
• Energy (ENER) 
• European Civil Protection and Humanitarian Aid Operations (ECHO) 
• Financial Stability, Financial Services and Capital Markets Union (FISMA) 
• Health and Food Safety (SANTE) 
• Internal Market, Industry, Entrepreneurship and SMEs (GROW) 
• Joint Research Centre (JRC)  
• Maritime Affairs and Fisheries (MARE) 
• Migration and Home Affairs (HOME) 
• Mobility and Transports (MOVE) 
• Regional and Urban Policy (REGIO) 
• Research and Innovation (RTD) 

The group met 4 times during the Evaluation process, first to steer work related to the support 
studies which were carried out for this evaluation, and then on the draft evaluation. The group 
was also consulted in writing. The members of the group were invited to all events organised 
in  the  context  of  the  consultation  process  described  in  Annex  II  of  this  report.  Details  on 
consultations on the Group are provided in the following table. 

59 

 
 
 
 
 
 
 
 
 
Date 
13 October 2020 

25 February 2021 

June 2021  

16 September 2021 meeting 

21 March 2021 meeting 

Topic of discussion 

Studies supporting the evaluation - 
Inception report, 
followed by written consultation 

Draft interim report presented by the 
contractor for the supporting studies, 
followed by written consultation 

Written consultation on the Revised draft 
interim report 

Draft final report 
followed by written consultation 

Discussion on Draft Commission 
evaluation report (Staff working 
document for the evaluation and 
executive summary) 
followed by written consultation 

3. 

Consultation of the Regulatory Scrutiny Board 

Following its examination by the Regulatory Scrutiny Board on 24 May 2022, this report was 
modified with the following main changes: 

Comment by the Board 
The  report  should  strengthen  the  cost-
benefit  analysis  of 
in 
particular by comparing the cost-benefit of 
agricultural use and incineration of sludge. 

the  Directive, 

The report does not draw clear and broader 
conclusions  on  the  lessons  learned,  in 
particular,  on  the  collection  of  data  and 
indicators to  be built  for future evaluation 
as well as whether the regulatory set-up in 
this  area  is  ‘fit  for  purpose’  in  view  of 
recent policy developments. 

When  reporting  on  stakeholders’  views, 
the  report  should  not  only  emphasise 
majority  views.  It  should  be  careful  to 
always  consider  all  views,  majority  and 
minority,  and  pay  more  attention  to  the 

Modifications made 
The  efficiency  and  cost-benefit  analysis 
was  revised  adding  additional  information 
from  most  recent  studies  of  the  JRC.  The 
reasons  for  the  wide  ranges  of  costs 
observed  were  explained,  also  explaining 
how  costs  vary.  Extensive  data  were 
harvested  on  aggregated  costs,  which  are 
more  representative  and  are  a  better  basis 
for the assessment. A particular focus was 
given to the comparison of cost-benefits of 
agricultural use vs incineration of sludge. 

The  lessons  learned  section  now  provides 
more  details  on  the  information  and  data 
which  would  be  needed  to  ensure  that  the 
objective of a high  level of environmental 
and health protection is met. 

The report now describes more extensively 
stakeholders’ 
results 
the 
distinguishes  more 
consultation. 
the  different 
systematically  between 
providing 
stakeholder 

groups, 

of 
It 

also 

the 

60 

 
 
 
 
underlying  arguments  of  stakeholders 
rather than to percentages. 

underlying  arguments  of  stakeholders 
rather than mere percentages. 

The  report  should  make  it  clearer  in  the 
conclusions  that  the  legal  basis  of  the 
Directive is  now outdated in  view both  of 
its  content  –  which  is  not  cross  border  in 
nature  -  and  of  the  development  of  the 
acquis in the period since it was adopted. 

This has been made more explicit. 

61 

 
 
 
 
 
ANNEX II. METHODOLOGY AND ANALYTICAL MODELS USED 

This  evaluation  has  been  supported  by  studies  undertaken  by  Wood.plc  for  that  purpose158, 
used as a basis adjusted and completed as appropriate Two studies carried out by the JRC also 
provided significant contributions to this work159.  

The sources of information used for this evaluation have been: 

-  A review of existing literature, including the previous evaluation and reports from relevant 

EU funded research projects.  

-  Member  States  implementation  reports;  data  from  Eurostat  and  from  the  European 

Environmental Agency 

-  Stakeholder  consultations,  to  gather  additional  data  and  information  on  the  stakeholders 
perception  of  the  extent  to  which  the  SSD  has  been  successfully  implemented  and  its 
relevance.  This  included  an  online  public  consultation  (OPC),  targeted  surveys  and 
interviews  (with  expert  stakeholders  and  with  Member  States),  and  a  stakeholder 
workshop. A wide range of stakeholders contributed, including Member State Competent 
Authorities,  Trade  Associations,  Non-Governmental  Organisations  (NGOs),  farming 
community and research organisations. 

A summary of the approaches used, and an overview of the findings is presented below. 

Literature review 

Over 300 academic journals, scientific reports, pan European studies, national reports, policy 
documents  and  legal  texts,  were  reviewed.  The  literature  reviewed  includes  Member  State 
(MS)  reports  on  the  implementation  of  the  SSD  also  analysed.  It  also  covers  information 
reported under the implementation of the UWWTD, where reporting of sewage sludge use is 
also required.  

All the information collected was screened before being used. The screening phase aimed at 
determining  the  relevance  of  the  source  and  took  in  consideration  the  year  of  publication 
(sources  after  2014  were  favoured)  and  the  geographical  scope  (EU  specific  sources  were 
favoured).  

The  literature  provided  evidence  in  relation  to  most  of  the  evaluation  criteria  (to  a  lesser 
extent for the EU added value analysis), there were however challenges  encountered during 
the review process which included: 

-  There is little/sparse information on typical sludge management processes in each country 
(e.g., there was no information readily available on what volumes of sewage sludge were 
subject to anaerobic digestion as an intermediate step before the final disposal rates were 
recorded). 

-  There  are  substantial  gaps  relating  to  the  production  and  use/disposal  of sewage  sludge 

and a lack of consistency and comparability in the types of data reported. 

-  There are several data gaps in all the datasets identified thus affecting the quality  of the 
data  used  for  the  assessment.  There  are  also  varying  datasets  on  sludge  volumes 

158  Evaluation  support  study;  Exploratory  on  prospective  elements;  Report  on  MS  implementation  2016-2018  and  further 

information on sludge management in each MS gathered in summary fiches 

159 Huygens, D. et al (2022); Egle, L. et al., 2023 - under development at the time of writing this report 

62 

 
 
 
                                                 
 
generated  and  used  in  agriculture  that  present,  in  some  instances,  conflicting  evidence 
(e.g., EUROSTAT versus implementation reports). This has made it challenging to get an 
accurate  picture  of  trends  on  use  of  sewage  sludge  in  agriculture.  Similarly,  there  are 
important gaps in the data reported on metal and nutrient contents in sludge. 

-  There are important gaps observed relating to elements of the assessment of the costs and 
benefits of the Directive. On that specific topic, many of the data sources in the literature 
review are relatively old. The literature review also revealed a scarcity of cost data from 
MS that have joined the EU after 2003. 

Stakeholder engagement 

Stakeholder engagement was necessary to ensure that all relevant and interested stakeholders 
were  given an opportunity to  express  their opinions and to  contribute to  the study. The key 
objectives  of  the  consultation  process  were  (i)  to  complement  already  known  data  and 
literature  on  the  implementation  of  SSD  and  (ii)  to  understand  the  extent  at  which  the 
Directive has been successfully implemented, the extent to which its objectives were met, the 
challenges it encountered, and whether there have been trade-offs in the implementation.  

The  stakeholder  engagement  included  an  online  public  consultation,  the  organisation  of  a 
workshop  and  targeted  consultation  (surveys  and  interviews).  A  very  brief  overview  is 
presented below. More details are available in the synopsis report in Annex I. 

  Online public consultation (OPC) 

The  OPC  included  questions  tailored  to  examine  the  effectiveness,  efficiency,  relevance, 
coherence, and EU added value of the SSD. The survey was available in all EU languages and 
available through the EU Survey platform.160 The consultation was conducted over a period of 
16 weeks (between November 2020 and March 2021). 

Respondents’ profile 

A total of 181 responses were received, with 22 EU Member States represented, as well as 3 
non-EU  countries.161  Figure  3.1  below  shows  a  breakdown  of  the  respondents’  sectors  that 
were represented in the OPC.  

Sector representation in the OPC 

160 https://ec.europa.eu/eusurvey/home/welcome  
161 Liechtenstein, Norway, and Switzerland 

63 

 
 
                                                 
Research and Education; 
4%

Other; 6%

Waste water treatment 
plants; 21%

Waste management; 15%

Food industry; 2%

Fertiliser and fertilising 
products industry; 9%

Compost and digestate 
industry; 7%

Farmers; 7%

Sewage sludge 
processing; 20%

Associations of producers 
or managers of sewage 
sludge; 8%

Source: OPC 

Over  70%  of  the  organisations  taking  part  in  the  consultation  process  were  involved  in  or 
directly  affected  by  the  recovery,  treatment  or  use  of  sludge  and/or  wastewater  and  80%  of 
these  respondents  indicating  having  a  good  or  excellent  understanding  of  the  treatment  of 
sewage sludge, of the implementation of the SSD, and/or knowledge of its legal text. 

  Targeted stakeholders’ engagement 

The  targeted  stakeholder  engagement  included  targeted  written  surveys,  one  stakeholders’ 
workshop and several interviews. 

Targeted surveys 

Targeted surveys were drafted to gather detailed feedback and data from stakeholders directly 
involved  in  the  implementation  of  the  SSD,  and/or  from  stakeholders  with  a  substantial 
expertise of the topic. A total of three different questionnaires were prepared: one directed at 
Member  States  competent  authorities,  one  directed  at  other  expert  stakeholders  and  an 
additional  targeted  consultation  was  undertaken  to  gather  data  concerning  the  costs  and 
benefits of the SSD.  

There was a total of 63 responses were received from all stakeholder types (which included 
Member  States,  individuals  from  the  wastewater  treatment  and  sludge  processing  and 
treatment industry, agricultural associations, academics and NGOS, etc). 

The  findings  from  the  targeted  surveys  demonstrate  that  respondents  were  in  strong 
agreement that the SSD had led to some improvements such as: 

  a  generally  sustainable  framework  for  the  use  of  sewage  sludge  in  agriculture 

(73% agree or strongly agree),  

 

increased safe use of sewage sludge in agriculture (64% agree or strongly agree), 
and  

  minimisation  of  pollution  and  health  risks  from  sewage  sludge  (65%  agree  or 

strongly agree)  

  However,  respondents  were  less  convinced  the  SSD  had  led  to  phosphorus  and 
nutrient  recycling  and carbon sequestration, or to  a measurable improvement  in 

64 

 
 
 
 
 
the quality of agricultural soils. Further findings from the surveys are included in 
the analysis of the evaluation questions below.  

Stakeholders’ workshop 

A  workshop  was  organised  to  support  expert  discussions  on  key  topics  (such  as  improving 
energy  efficiency  in  wastewater  management  and  sludge  management,  increasing  nutrient 
recovery, and addressing pollution from micropollutants) and to present preliminary findings 
of  the  analysis.  The  workshop  was  organised  focusing  on  synergies  between  wastewater, 
sludge, and the circular economy.   

The workshop was very well attended with 376 participants attending the one day and 290 on 
the other day. A workshop report is available for further details.162 

Follow up interviews 

Five expert interviews with experts were organised to fill gaps in the information including on 
costs  and  benefits,  on  the  possibility  to  improve  quality  of  sludge  at  source  and  on  factors 
affecting trust from the public. Organisations representing farmers were also reached out to.  

The  interviewees  included:  a  representative  from  WAREG,  a Romanian  Water  Regulator,  a 
representative of a wastewater operator in Bulgaria and a representative of a pilot project in 
Lithuania aiming at using sewage sludge digestate as fertiliser for forestry plantation. Finally, 
an interview was held with a representative of the European Sustainable Phosphorus Platform. 

Data limitations 

There are several existing datasets on the volume of sludge generated and used in agriculture 
that present, in some instances, conflicting information albeit coming from normally reliable 
sources163. There are also gaps in all the datasets considered, i.e., there is not one that can be 
considered more robust or more complete. Collectively this means it was challenging to get an 
accurate  picture  of  trends  on  the  use  of  sewage  sludge  in  agriculture  and  other  uses  (e.g., 
amount composted or digested). In addition, there the information reported by Member States 
in  their implementation reports is  often missing, and sometimes the quality of data reported 
on metal and nutrient contents is of limited quality. 

The following table illustrates the extent of the data gaps, taking the example of data on the 
production  of  sludge  and  share  used  in  agriculture.  To  address  these  challenges,  this 
evaluation used the data reported by Member States under the implementation of the SSD as 
main  dataset  and  proceeded  to  fill  observed  gaps  using  Eurostat  data.  The  implementation 
data was deemed most suitable as this is the data reported by the Member States’ competent 
authorities in charge of the implementation of the SSD and those that can be assumed to be 
most accurate about their datasets164. As explained below, a further extrapolation of data was 
undertaken to have a complete data set to use for the purpose of the analysis. 

Such  extrapolation  has  notably  been  done  for  the  graph  showing  the  evolution  of  sewage 
sludge production and use over 2007-2018 (starting from 2007 because  before that the data 
scarcity is too extreme), provided in the main body of this evaluation report, section 3.2. 

162 Workshop report on wastewater and sludge, https://circabc.europa.eu/w/browse/907e1488-b9e3-42d7-804c-eafeca890ca4 
163 Eurostat, reporting under the SSD implementation and reporting under the UWWTD implementation 
164  In  particular,  the  evaluation  of  the  UWWTD  noted  the  challenge  for  some  competent  authorities  to  report  on  sewage 

sludge when it is not part of the responsibilities of the water authorities in some Member States 

65 

 
 
                                                 
The graph was originally as follows, when based solely on the implementation reports from 
Member  States,  before  completion  from  other  data  sources  and  extrapolations  using  other 
years of reporting where data from Member States were missing for a given year: 

Total sludge produced and used in agriculture in the EU between 2007 and 2018  

Source: Member States implementation reports required by the Directive, sent to the Commission on a 3-yearly basis  

This  would  show  an  increase  in  both  sludge  production  and  sludge  used  in  agriculture 
between  2009  and  2010.  Since  2010,  the  amount  of  sludge  used  in  agriculture  has  stayed 
relatively constant, albeit with a decline and subsequent increase between 2013-15. This can 
be explained in part due to an absence of reporting on sludge used in agriculture during this 
time period by some Member States. In terms of the total amount of sludge produced, there 
was an increase between 2012 and 2013 followed by a subsequent decrease between 2014 and 
2015, and a further increase between 2015–2016.  There is a decline in 2018, which similarly 
has been impacted by some Member States not reporting on sludge production for the most 
recent year. It should be noted that reporting from the UK has not been included in the chart 
below. 

When considering these trends one should acknowledge significant gaps in the data reported 
by each Member State for different years, which distort the aggregate total amounts for both 
total sludge production and sludge used in agriculture and, therefore, do not allow for definite 
identification of trends. The following table shows the gaps:  

Gaps in reporting on the total sludge production and use of sludge in agriculture between 2007 and 
2018  

Year 

Number of MS not having reported total 
sludge production  

Number of MS not having reported 
quantity of sludge used in agriculture 

2007 

18 MS 

2008 

18 MS 

2009 

18 MS 

18 MS 

19 MS 

18 MS 

2010 

5 MSs and 3 MS regions 

6 MS and 1 MS region 

2011 

5 MS and one MS region 

6 MS 

66 

 
 
 
Year 

Number of MS not having reported total 
sludge production  

Number of MS not having reported 
quantity of sludge used in agriculture 

2012 

5 MS and 3 MS regions 

7 MS and one MS region 

2013 

6 MS and 3 MS regions 

6 MS and 3 MS regions 

2014 

6 MS and 3 MS regions 

7 MS and 3 MS regions 

2015 

8 MS 

9 MS and one MS region 

2016 

1 MS and 3 MS regions 

1 MS and 3 MS regions 

2017 

1 MS and 3 MS regions 

1 MS and 3 MS regions 

2018 

4 MS and 3 MS regions 

3 MS and 3 MS regions 

Source: MS implementation reports. The 2007-2009 reporting on sludge production and sludge used in agriculture is lacking for 
18 Member States, data for the 2010-2012 period is missing for 8 Member States, data for the 2013-2015 period is missing for 7 
Member States and data for the 2016-2018 period is missing for 5 Member States. 

In order to avoid distortions in the representation of the data, the gaps were filled in through 
two steps: 

-  Where available, previous implementation reports were reviewed to fill any gaps 
-  The remaining data gaps were estimated through extrapolation of the existing data for 
the Member States  which had not  reported the data. The  extrapolation  was based on 
the  population  size  of  each  Member  State.  The  approach  has  therefore  relied  on  the 
assumption  that  a  Member  State  with  a  larger  population  has  produced  a  greater 
amount of sludge and/or uses a greater amount of sludge in agriculture. 

After completion with data from other sources and the extrapolation as described above, the 
diagram  appears  significantly  different  (this  diagram  is  also  the  one  provided  in  the  main 
body  of  this  report,  section  3.2).  The  resulting  figure,  as  provided  in  the  main  body  of  this 
evaluation report, section 3.2, is as follows: 

Sludge produced and used in agriculture in the EU (2007-2018) 

67 

 
 
 
 
 
Source: MS reporting on the implementation of the SSD, complemented with extrapolation where information is missing for that 
period (see Annex II for details on how the extrapolation was made). The graph has been drawn from 2007 onwards, due to the 
extreme scarcity of data from before that (and although we still note that even after 2007, data sets remain very incomplete, as 
described in Annex II). The most notable yearly change occurred between 2012–2013, when there was a sharp decrease. The 
decrease is a reflection of reduced total sludge production reported in Spain, Finland and Portugal. There was no information 
identified to explain these decreases in these countries. A further decrease is observed between 2017-2018 reflecting decrease in 
quantities reported by Bulgaria and Italy. 

Discrepancies between Eurostat, Member States’ data on sludge use 

It is challenging to conclude on trends in management of sludge in EU due to differences in 
the terminology and type of data collected. 

Research has been undertaken to understand the reasons for these differences. Terminology is 
unclear,  which  can  lead  to  varied  interpretation.  For  example,  all  data  on  sewage  sludge 
production and disposal route refers to sewage sludge dry matter, but there is no definition of 
dry matter in the SSD. It is noted that there has been an international standard since 1993 and 
a  European  standard  since  2000165.  Eurostat  distinguishes  ‘agriculture’  from  ‘compost  and 
others’. Based on some countries’ evolution of reported data it is safe to assume that in some 
MS  the  ‘other’  category  also  includes  agriculture  use166.    In  addition,  sludge  that  is  used  to 
grow plants for further compost production can be classified differently in MS (i.e., ‘reuse in 
compost’,  or  ‘other’).  The  literature  identified  challenges  in  interpreting  and  comparing  the 
data available167. 

Each dataset has pros and cons depending on the year/period and type of data considered: 

-  The MS implementation  reports provide a more  comprehensive dataset  for the  years 
2016-2018  (however,  missing  data  from  Germany  for  2018 
impacts 
considerably  the  2018  reporting168),  from  2007  through  to  2016,  Eurostat  provides 
more comprehensive data. 

likely 

-  Eurostat  only  gives  limited  insight  into  sewage  sludge  disposal.  There  is  little 
information  in  the  data  and  literature  studied  on  the  full  detail  of  the  typical  sludge 
management processes in each country. For example, there was no information readily 
available on what  volumes  of sewage sludge were subject  to the anaerobic digestion 
treatment  as  an  intermediate  step  before  the  final  disposal  fates  recorded.  This  pre-
treatment will impact on the actual volumes of sludge finally disposed of (anaerobic 
digestion significantly reduces volume) and the amount of energy recovered. 

Data  collected  under  the  different  sources  are  not  fully  coherent  and  can  be  challenging  to 
compare.  A  comparison  of  the  data  concluded  to  a  ‘high  degree  of  incongruity  in  37%’  of 
MS169. The incoherence of the datasets has been further identified in several references170.  

165 ISO 11465,1993, CSN EN 12880,2000 CSN EN 15934, 2012 
166  Collivignarelli,  M.,  Abbà,  A.,  Frattarola,  A.,  Carnevale,  M.,  Padovani,  S.,  Katsoyiannis,  I.,  &  Torretta,  V.  (2019). 
Legislation  for  the  Reuse  of  Biosolids  on  Agricultural  Land  in  Europe:  Overview.  Sustainability,  11(21).  Retrieved 
January 21, 2021, from https://www.mdpi.com/2071-1050/11/21/6015/htm  

167  Collivignarelli,  M.,  Abbà,  A.,  Frattarola,  A.,  Carnevale,  M.,  Padovani,  S.,  Katsoyiannis,  I.,  &  Torretta,  V.  (2019). 
Legislation  for  the  Reuse  of  Biosolids  on  Agricultural  Land  in  Europe:  Overview.  Sustainability,  11(21).  Retrieved 
January 21, 2021, from https://www.mdpi.com/2071-1050/11/21/6015/htmet al. (2019).  

168 Considering our scenario analysis developed for the JRC, Germany used 274,603 tonnes of sewage sludge on agriculture 

in 2018. 

169  Bianchini,  A.,  Bonfiglioli,  L.,  Pellegrini,  M.,  &  Saccani,  C.  2016.  Sewage  sludge  management  in  Europe:  a  critical 
analysis  of  data  quality.  International  Journal  of  Environment  and  Waste  Management,  18(3).  Retrieved  February  08, 
from 
2021, 

68 

 
 
                                                 
 
 
-  Triangulation was possible for most questions. The evaluation questions were covered in 
the  OPC,  the  targeted  consultation  and  were  also  investigated  in  the  literature  thus 
allowing conclusions to be drawn from a range of sources. In some cases where available 
literature was limited (e.g., efficiency, EU added value) or conflicting (e.g., in particular 
for  data  sets),  to  the  evaluation  relies  to  a  large  extent  on  consultation  responses  rather 
than  on  available  literature.  Where  difficulties  were  encountered  in  relation  to  the 
robustness  of  the  evidence  upon  which  conclusions  have  been  drawn,  these  difficulties 
have been identified and clearly presented in the analysis of each evaluation question. 

2. Development of the scenarios of reference (for the baseline) 

The scenarios of reference are: 

-  Past Scenario reflecting the situation at the time the Sewage Sludge Directive (SSD) was 
adopted.  The  data  used  are  the  oldest  possible  after  1986  (year  of  the  start  of 
implementation of the Directive). 

-  Present  Scenario (Current  Situation). The data was derived mainly from  the information 
reported  by  MS  as  part  of  the  implementation  of  the  SSD  and  reflects  latest  data  from 
2016-2018  reporting  period.  Where  necessary  gaps  have  been  filled  with 
the 
corresponding most recent data from Eurostat. When MS have supplied more recent data 
(e.g., as part of the consultation step) these have been preferred as considered more robust. 
-  The Present Scenario (WIND) reflecting a hypothetical present scenario whereby the SSD 
would  not  have  been  adopted.  The  scenario  is  based  on  an  extrapolation  of  the  current 
situation  considering  qualitative  criteria  such  as  Member  States  adopting  stricter 
requirements171.  If  the  Member  State  had  not  adopted  stricter  requirements  for  sewage 
sludge,  we  assumed  that  the  Present  Scenario  (WIND)  would  be  50%  higher  than  the 
Present  Scenario  (current  situation),  meaning  50%  more  than  the  currently  discarded 
sewage sludge. The choice of this value was arbitrary, based on observed variation of use 
of sewage sludge in countries that did not practice it before the adoption of the SSD and 
the current situation (e.g., Bulgaria, Estonia, Greece and Ireland). This value was chosen 
so that it was large enough to show a change between the Present Scenario (WIND) and 
the  Present  Scenario  (current  situation)  and  for  illustrative  purposes.  The  value  of  the 
WIND scenario is as a comparison to the current situation, and to support the analysis of 
the attribution of the effects observed to the SSD. 

The  table  below  presents  the  estimated  shares  for  the  use  of  sewage  sludge  in  agriculture 
under the different scenarii considered. With all the precautions to be taken due to the scarcity 
and quality of data, this would suggest that the Directive had either no effect (13 MS) on the 

https://www.researchgate.net/publication/311273547_Sewage_sludge_management_in_Europe_a_critical_analysis_of_
data_qualityet al., 2016.  

170  Bianchini,  A.,  Bonfiglioli,  L.,  Pellegrini,  M.,  &  Saccani,  C.,  2016.  Sewage  sludge  management  in  Europe:  a  critical 
analysis  of  data  quality.  International  Journal  of  Environment  and  Waste  Management,  18(3).  Retrieved  February  08, 
from 
2021, 
https://www.researchgate.net/publication/311273547_Sewage_sludge_management_in_Europe_a_critical_analysis_of_
data_qualityet al. , 2016 .  

171 Modelling work had originally been envisaged for the development of a baseline scenario. However, the scarcity of  data 
on sludge use, sludge quality and soil quality did not allow this. Instead, extensive efforts have been made to gather as 
many data as possible and present a comparison past situation/present situation. 

69 

 
 
                                                                                                                                                         
 
percentage of sludge use in agriculture, or that it would cause a decrease of that percentage (6 
MS). 

Past, Present (Current Situation), and WIND scenario for the share of sewage sludge used in agriculture 

Member State 

Past Scenario, % 

Present Scenario 
(Current 
Situation), % 

Present Scenario 
(WIND), % 

Austria 

Belgium 

Bulgaria 

Croatia 

Cyprus 

Czechia 

Denmark 

Estonia 

Finland 

France 

Germany 

Greece 

Hungary 

Ireland 

Italy 

Latvia 

Lithuania 

Luxembourg 

Malta 

Netherlands 

Poland 

Portugal 

Romania 

Slovakia 

Slovenia 

Spain 

Sweden 

33.01 

22.01 

0.02 

5.03 

89.04 

43.05 

62.01 

0.06 

60.07 

62.51 

46.01 

1.01 

20.08 

10.01 

45.09 

42.06 

33.06 

55.01 

0.06 

42.01 

9.010 

4.011 

0.06 

80.05 

6.012 

52.01 

29.013 

30.014 

65.011 

56.111 

6.111 

11.111 

31.011 

67.014 

71.111 

43.714 

24.714 

15.314 

20.014 

7.414 

98.914 

40.214 

17.414 

14.011 

20.714 

0.014 

3.014 

20.314 

2.011 

32.614 

0.014 

0.011 

78.011 

39.011 

70 

30.0 

65.0 

84.2 

6.1 

16.7 

31.0 

67.0 

100.0 

43.7 

24.7 

15.3 

30.0 

7.4 

100.0 

40.2 

17.4 

14.0 

20.7 

0.0 

3.0 

30.4 

3.0 

32.6 

0.0 

0.0 

100.0 

39.0 

 
 
Notes : 
1 - https://ec.europa.eu/environment/water/water-urbanwaste/implementation/implem_report_1/chap6.html 
2 - 
https://moew.government.bg/static/media/ups/tiny/file/Waste/sewage_sludge/BG_DE_seminar/Presentation_NSMP_Schneider_B
ulgaria-4.pdf 
3 - Based on earliest data identified for 2010 
4 - Based on latest Eurostat data available for 2009 
5 - https://www.ircwash.org/sites/default/files/821-EUREAST94-14809.pdf 
6 - https://pubmed.ncbi.nlm.nih.gov/22336390/  
7 - Based on EC, First implementation report of the UWWTD and https://ec.europa.eu/environment/water/water-
urbanwaste/implementation/implem_report_1/chap6.html and 2014, Puhdistamolietteen ja biojätteen käsittely ravinteita 
kierrättäen 
8 - https://dea.lib.unideb.hu/dea/bitstream/handle/2437/214183/file_up_5-Wastewater Treatment and Sludge Utilisation in 
Hungary-1.pdf?sequence=1 
9 - Assuming a gradual reduction in use over time, e.g., 35% of use in 2010 
10 - https://www.mdpi.com/2071-1050/12/9/3686/pdf 
11 - Value provided by Member State 
12 - https://cdr.eionet.europa.eu/si/eu/colqa8jlq/colqwzskg/envqwzsra/Directive_86_278_sewage_sludge.htm 
13 - https://ec.europa.eu/environment/archives/waste/sludge/pdf/part_iii_report.pdf  
14 – Calculated from quantity of ‘sludge used in agriculture’ and ‘total sludge use’ data in order of preference: Member State-
provided data, 2018 Implementation data, Eurostat data (2018, 2017 or 2016 in order) 

As can be seen above from the details on the data sources, it has shown extremely difficult to 
gather information to fill that table. As a result, it was decided to focus this baseline on sludge 
use (i.e., not developing it for other parameters such as sludge heavy metal content) and on a 
comparison “situation / present situation” rather than an evolution.  

71 

 
 
 
 
 
 
ANNEX  III.  EVALUATION  MATRIX  AND,  WHERE  RELEVANT,  DETAILS  ON  ANSWERS  TO  THE 
EVALUATION QUESTIONS (BY CRITERION) 

5.3  1.1  Evaluation matrix 

In line with the Commission's better regulation policy, this report assesses the Sewage Sludge 
Directive  along  five  criteria:  effectiveness,  efficiency,  coherence,  EU  added  value,  and 
relevance.  These  criteria  were  operationalised  via  elaborating  questions  specific  to  this 
Directive, which were systematically answered to assess the different criteria in a way that is 
specific to the Directive (how these criteria translate in the context of this Directive). This set 
of (18) questions was also provided in the Roadmap published at the start to inform citizens 
and stakeholders to allow them to provide feedback on the evaluation initiative. 

These  questions  were  broken  down  into  sub-questions,  and,  for  each  of  them,  assessment 
criteria,  indicators,  approach  to  take  for  the  analysis  and  sources  of  information  to  use  to 
answer  the  questions  were  identified.  This  resulted  in  the  evaluation  matrix  presented  here. 

72 

 
 
 
5.3.1.1  Evaluation matrix - effectiveness 

Sub-questions 

Assessment criteria 

Indicators 

Data analysis approach 

Data sources/Data 
collection methods 

EQ.1 What progress has been made over time towards achieving the objectives and targets set out in the SSD in the various Member States? To what extent have the 
objectives been met? 

1.1 What has been the effect of the 
SSD on the use of sewage sludge in 
agriculture? 

1.2 What has been the impact of 
the SSD on the quantity of sewage 
sludge used in agriculture? 

Member State Regulation of sewage 
sludge in agriculture. 
Proportion and volume of sewage sludge 
discharged to the marine environment has 
reduced in the EU and Member States. 
Reduced reports of sewage sludge in the 
marine environment. 
Reporting of annual concentrations of 
heavy metals in sludge.  
It will be important to decouple quantity 
of use and achievement of the objectives, 
a decrease of use might be due to other 
substances present in the sludge and not 
necessarily a failure to achieve objectives 

Number of Member States 
implementing regulations 
concerning sewage sludge use in 
agriculture. 
Member States having set other 
requirements in their national 
legislation (i.e., stricter) including 
limit for maximum quantity of 
sludge 
Proportion and volume of 
sewage sludge used in 
agriculture in the EU and 
Member States as one indicator 
to be completed by analysis.  
Proportion and volume of 
sewage sludge discharged to the 
marine environment. 

Overall perception that sewage sludge is 
used effectively in agriculture  
Demand for sewage sludge for agriculture 
has increased and demand for other 
fertilisers has reduced.  
It will be important to decouple quantity 
of use and achievement of the objectives, 
a decrease of use might be due to other 
substances present in the sludge and not 
necessarily a failure to achieve objectives 

Trade statistics 
Proportion and volume of 
sewage sludge used in 
agriculture.  
Number of sewage sludge 
producers providing sewage 
sludge to agricultural users.  
Quantity of nutrients recovered 
from sludge compared with 
those from manure.  

73 

Quantitative analysis of 
sewage sludge use globally 
and in comparison, with the 
EU and MS.  
Qualitative analysis of MS 
reported data  

Implementation report 
Eurostat 
JRC modelling 
Feedback from stakeholders 
(including Roadmap) 

Quantitative analysis of 
sewage sludge quantities in 
agriculture, by MS.  
Comparison of sewage 
sludge with other fertiliser / 
nutrient sources including 
manure 

Implementation report 
Eurostat 
JRC modelling 
Feedback from stakeholders 
(including Roadmap) 

 
 
Sub-questions 

Assessment criteria 

Indicators 

Data analysis approach 

Data sources/Data 
collection methods 

1.3 How effective has the SSD been 
regarding the concentrations of 
heavy metals in soil? 

MS Regulation of use of sludge in soil 
where concentrations of heavy metals 
exceed the values laid down in the SSD 
Reports of concentrations by MS 

Concentrations of heavy metals 
in soils in different MS where 
different quantities of sludge are 
used. 

Quantitative analysis of 
concentrations of heavy 
metals in soils reported 
within MS and at EU-level.  

Implementation report 
Eurostat 
JRC modelling 
Literature review 

1.4 How effective has the SSD been 
in encouraging the correct use of 
sewage sludge in agriculture? 

Changes observed in the correct use of 
sewage sludge in agriculture 
Actions used in MS to encourage correct 
use and uptake for agricultural use. 

Size of actions for 
encouragement 

EQ.2 - What factors have contributed to or hindered their achievement? 

2.1 How effective has the 
transposition of SSD been at MS 
level? 

2.2 What are the other factors that 
have contributed to the 
achievements of the objectives? 

National laws implemented by MS and 
their content. 

National laws implemented by 
MS and their content. 

The interpretation of the Directive has 
been straightforward. 
Other factors as identified by stakeholders 
to have contributed to the achievements 
of the Directive (e.g., effective record 
keeping, effective sharing of information) 

Court case jurisprudence 

Stakeholder consultation 

Quantitative analysis of 
usage data and trading data  
Qualitative analysis of 
consumers views, citizens 
views and producers’ views.  
Qualitative analysis of 
communication methods in 
MS.  

Qualitative analysis of MS 
national laws and legal 
frameworks for 
implementing the SSD.  

National laws 
MS Reports to the 
Commission 
Literature review 

Qualitative analysis of legal 
infringement and 
enforcement 

EU Court cases 
National proceedings 

EQ.3 - How effective has the implementation and enforcement of the SSD been in the 28 Member States and to what extent has this safeguarded agricultural soils from 
pollution? 

3. 1 How effective has enforcement  Competent Authorities in MS have access 

Cooperation between 

Qualitative comparison of 

Consultation with 

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Sub-questions 

Assessment criteria 

Indicators 

Data analysis approach 

of the SSD in the Member States 
been? 

to reports and the tools to undertake 
enforcement in MS.  

Competent Authorities and MS.  
Feedback from Competent 
Authorities. 

enforcement activities 
between MS. 

3.2 How effective has MS 
implementation of the SSD been? 

3.3 Have agricultural soils quality 
been safeguarded from the 
implementation of the SSD?  

Implementation of key obligations at 
national level, and consistent in MS across 
the EU 
National law fully includes obligations of 
the SSD 
Additional actions have been taken by MS 
to facilitate SSD implementation 

Link between the adoption of the 
legislation and quantity of the quality of 
soil 
Findings on overall heavy metals 
concentration in agricultural soils in EU 28 
and through time 

Awareness and understanding of 
regulation amongst users of 
sewage sludge in agriculture, and 
citizens.  

Qualitative analysis of 
viewpoints from Competent 
Authorities across MS.  

Reporting on ‘Quality of soils’  

Qualitative analysis of views 
of users and producers of 
sewage sludge.  
Qualitative analysis of 
Competent Authority 
viewpoints  
Comparison with other non-
EU countries where sewage 
sludge use is not regulated 

Data sources/Data 
collection methods 

competent authorities, 
producers, and users 
MS reports concerning 
enforcement  
Infringements at EU level  

Stakeholder consultation 
(including Roadmap) 

Stakeholder consultation 
(including Roadmap) 

EQ.4 - What have been the (quantitative and qualitative) effects of the SSD? 

4.1 Have the amounts of sewage 
sludge used in agriculture 
changed? 

Levels of sewage sludge in the marine 
environment have changed 
Levels of sewage sludge used in 
agriculture have changed 
Proportion of use is greater in agriculture 
than discharged to the marine 
environment 
There are changed disposal patterns  

Levels of sewage sludge used in 
agriculture 
Proportion of sewage sludge 
discharged in the marine 
environment  
Comparison of sewage used in 
agriculture vs other uses 

Quantitative analysis of 
levels of sewage sludge 
Qualitative analysis of other 
pollutants affected 
implementation of SS 
Qualitative analysis of 
impacts of soil 
contamination on health 

Literature review 
Stakeholder consultation 
(including Roadmap) 
Datasets and reports  

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Sub-questions 

Assessment criteria 

Indicators 

Data analysis approach 

Data sources/Data 
collection methods 

4.2 What has been the public 
perception, media reporting and 
food industry views concerning 
sewage sludge use in agriculture 
and how did it influence it?  

4.3 What are the other effects of 
the SSD? 

There are changes in health risks from use 
of sludge on agricultural land. 

Positive / negative public viewpoint 
reported  
Position of food industry on use of sewage 
sludge 

Viewpoints of citizens in MS 
Newspaper articles and 
communications 

Qualitative analysis of 
viewpoints of citizens 

Open Public Consultation 
Literature review 

Other effects either quantitative or 
qualitative that can be linked to the 
implementation of the SSD 
Other effects into pollutants 
Effects on human health 
Wider effects on the environment and 
health effects of contaminated soils are 
better understood 

Indicators to be set based on the 
effects identified 
WHO information on human 
health 

Qualitative and quantitative 
analysis of the effects 
identified 

Literature review  
Targeted stakeholder 
consultation/interviews 

EQ.5 - What have been the unintended / unexpected effects of the SSD? 

5.2 Has there been a shift to 
alternative uses or disposal routes 
of sewage sludge other than use in 
agriculture? 

Other available uses or disposal routes 
other than of sewage sludge in agriculture 
(biosolids) 
Impact of the national rules on such a use 
of alternatives, if available.  
Rules set by Member States to regulate 
other uses/disposal routes 

Different uses / disposal routes / 
Types of waste-derived products 
available 
MS rules on management of 
sludge 

Literature review  
Targeted stakeholder 
consultation/interviews 

Qualitative analysis of 
available products 
Quantitative analysis of 
products used 
Qualitative analysis of 
sewage sludge users’ 
preferences and viewpoints 
and market demand where 
applicable. 

5.2 What are the other unintended 
/ unexpected effects of the SSD 

Other unintended or unexpected effects 
that can be linked to the implementation 
of the SSD 
New treatments available 

Indicators to be set based on the 
effects identified 

Qualitative and quantitative 
analysis of the effects 
identified 

Literature review  
Targeted stakeholder 
consultation / interviews. 

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Sub-questions 

Assessment criteria 

Indicators 

Data analysis approach 

Data sources/Data 
collection methods 

New technologies available 
Changes in emissions of GHG linked to 
application of sewage sludge on 
agricultural land. 

5.3.1.2  Evaluation matrix – efficiency 

Sub-questions 

Assessment criteria 

Indicators 

Data analysis approach 

EQ.6 - To what extent has the SSD been cost-effective? Are the costs related to the SSD proportionate to the benefits? 

6.1 What are the costs and 
benefits arising from 
implementation of the 
Directive? 

6.2 How proportionate were 
the costs of the intervention 
borne by different stakeholder 
groups considering the 
distribution of associated 
benefits? 

To what extent are costs arising 
from regulatory requirements 
minimised? 
What is the cost? 
What are the benefits? 
How do the costs and benefits 
compare in total and across 
stakeholder groups? 

Administrative costs to operators for 
maintaining up to date records on 
quantities of sludge. 
Administrative costs to authorities 
associated with provision of the 
consolidated report on implementation of 
SSD (Article 17).  
Administrative costs to farmers. 

Operational costs to operators for the 
following treatment options: 

- 

- 

Transporting and spreading raw 
sewage sludge on land 
Transporting, treating, and 
spreading sewage sludge on land  

-  Dewatering and incinerating of 

- 

sewage sludge 
Landfilling of sewage sludge (incl. 
relevant pre-treatment)  
Operational impacts on farmers from using 

77 

Quantitative assessment of 
administrative costs to 
authorities (if considered 
significant, using aspects of 
the standard cost model 
methodology).  
Quantitative assessment of 
operational costs to 
operators, depending on the 
treatment option.  
Quantitative assessment of 
cost saving to farmers based 
on the comparison with 
costs of using alternative 
fertilisers. 
Comparison of the above 
costs with the benefits (as 
specified in Table 3.3.) 

Data sources/Data 
collection methods 

Literature review of grey 
literature including the 
previous evaluation (Bio 
Intelligence Service, 
2014) 

Targeted stakeholder 
consultation. 

A number of case studies 
covering representative 
causes of variations 
across Member States 
including: 
- 

Population 
connected to 
urban 
wastewater 
treatment in 
relation to 

 
 
 
 
 
 
 
 
 
Sub-questions 

Assessment criteria 

Indicators 

Data analysis approach 

sludge: 

- 

Constraints and increased 
planning requirements for 
agricultural activities, time costs 
-  Net cashflow impact integrating 
financial flows related to sludge 
use / disposal and change in 
chemical fertiliser expenditure. 

Changes in soil quality and fertiliser uptake 
efficiency resulting from use of sludge as 
compared to other fertilisers.  
Impacts on human health resulting from 
the effectiveness analysis. 

Impacts on the environment using 
effectiveness analysis. 

Avoided contamination 
caused by regulation of 
sludge use. 

Comparison of nitrous oxide 
and methane emissions 
resulting from different 
treatment options 
(spreading on land, 
incineration, or landfilling). 

Data sources/Data 
collection methods 

suitable 
agricultural soil 
in the country 

-  Historic 

developments 
related to 
phosphorus 
and nitrogen 
excess or deficit 
in soils 

-  Distance from 
wastewater 
treatment 
plants to 
suitable 
agricultural 
lands.  

EQ.7 - To what extent do the requirements of the SSD influence the efficiency with which the observed achievements have been attained? What other factors 
influence the costs and benefits? 

7.1 How much have actions 
changed implementation costs 
while maintaining control and 
quality standards of the 
Directive? 

7.2 What are the non-
regulatory drivers of costs and 
benefits? 

Are there examples of good 
practices? 

Approaches to implementation and 
associated implementation costs. 

Qualitative review of 
implementation to identify 
examples of cost savings. 

Targeted stakeholder 
interviews 

Case studies 

What non-regulatory factors 
have influenced the efficiency 
with which the observed 
achievements have been 
attained? 

Technological developments to improve 
the quality of wastewater and sewage 
sludge treatment and recovery. 
Technological developments for the 
feasibility of the analysis and removal of 

Case studies to review what 
technological and scientific 
developments there have 
been, the extent to which 
the SSD has been driver of 

Literature review of grey 
literature including the 
previous evaluation (Bio 
Intelligence Service, 
2014) 

78 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
Sub-questions 

Assessment criteria 

Indicators 

Data analysis approach 

substances/contaminants in sewage sludge. 
Member State use of more stringent 
measures (Article 12). 

these developments, and a 
review of the associated 
costs and benefits 
Screening to review costs 
and benefits arising from 
Member State use of more 
stringent measures. 

Data sources/Data 
collection methods 

Targeted stakeholder 
interviews 

EQ.8 - Are there opportunities to simplify the legislation or reduce unnecessary regulatory costs without undermining the intended objectives of the intervention? 

8.1 To what extent are there 
opportunities for synergies and 
cost savings with related EU 
legislation? 

There are opportunities for 
synergies, there is opportunity 
for simplification and / or to 
remove unnecessary regulatory 
costs. 

Overlaps of reporting 

Relevance of reporting 

Objectives and outputs of related EU 
legislation (UWWTD, EPRTR, Other): 
- 
requirements  
- 
requirements 
- 
reporting on compliance (i.e., are reporting 
requirements appropriate in matters of 
frequency, measurement technology 
relevant).  

Approach of measuring and 

Qualitative review of related 
EU legislation to identify 
synergies, e.g., with 
requirements for Nutrient 
Management Planning and 
support for Precision 
Farming.  

Desk based review of 
evaluation studies for 
related legislation 
Targeted stakeholder 
interviews 

8.2 How have different 
monitoring and enforcement 
techniques / approaches 
differed?  

Are there different approaches 
to monitoring and enforcement 
across the Member States and 
how do they differ in terms of 
their cost effectiveness?  

8.3 How are SMEs affected by 
the Directive? 

Are SMEs disproportionately 
affected by incurred costs? 

Approaches and techniques used for 
monitoring and enforcement across EU 
Member States  

Qualitative analysis of the 
approaches used and their 
associated costs and 
benefits.  

Targeted stakeholder 
interviews 

Administrative cost estimates in relation to 
business size. 
Evidence on the use of Article 11 
exemptions 
Differentiation in use of sludge across 

Analysis of the involvement 
of SMEs in the value chain. 
Application of Article 11 
exemptions across Member 
States (reduced reporting for 

Targeted stakeholder 
questionnaire 
Targeted stakeholder 
interviews 

79 

 
 
 
 
Sub-questions 

Assessment criteria 

Indicators 

Data analysis approach 

Data sources/Data 
collection methods 

different farm enterprise sizes. 

sewage treatment plants 
with a treatment capacity 
below 300 kg BOD5 per day, 
corresponding to 5 000 
person equivalents).  

EQ.9 - Are there significant differences in costs (or benefits) between Member States, and if so, what are the underlying causes? How do these differences link to the 
SSD? 

9.1 How do costs and benefits 
compare between Member 
States that have set more 
stringent sludge quality 
standards and those that have 
not? 

How do the costs and benefits 
compare between MS? 
Do more stringent standards 
drive different technology 
choices and as a result the 
associated costs?  

Comparison of costs incurred by operators 
Member States (see indicators used in EQ6).  

Comparison between costs 
and benefits arising from 
Member State use of more 
stringent measures and 
those arising from standard 
implementation. 

9.2 What bearing do local and 
geographical factors have on 
costs and benefits? 

Background concentrations of heavy metals 
in soil. 
Background excess of nitrogen and 
phosphorus. 
Member State use of more stringent 
standards. 

Qualitative review to assess 
the extent to which varying 
local and geographical 
factors require stricter 
conditions to meet the 
requirements of the 
Directive. 

Desk based review of 
previous evaluation 
study (BIO Intelligence, 
2014)  
Targeted stakeholder 
interviews 
Case studies 

Desk based review of 
previous evaluation 
study (BIO Intelligence, 
2014)  
Targeted stakeholder 
interviews 
Eurostat data 
Infringement processes 
vs MS linked water 
contamination 
WHO Soil and marine 
contamination? 

EQ.10 - How timely and efficient is the process for reporting and monitoring? 

10.1 Should Member State 

Is reporting and monitoring 

Assess the significance of 

Review of E-PRTR data 

80 

 
 
 
 
 
Sub-questions 

Assessment criteria 

Indicators 

Data analysis approach 

records be reported to the EU 
annually? 

proportionate to the scale of 
sewage sludge use and its 
environmental pressures? 

10.2 To what extent is 
reporting and monitoring 
aligned with technological and 
scientific developments? 

To what extent does annual 
recording and the consolidated 
reports (issued every four years) 
cover new substances and re-
use? 

Identification of new substances that may 
be found in sewage sludge. 
Reporting on re-use of sewage sludge. 

releases to land from the use 
of sewage sludge in relation 
to releases from facilities 
reporting to the E-PRTR. 

Screening of new substances 
compared with Member 
State record keeping and 
reporting. 
Screening of re-use 
compared with Member 
State record keeping and 
reporting. 

Data sources/Data 
collection methods 

and Member State 
sewage sludge records 
LUCAS 

Desk based review of 
evaluation studies for 
related legislation 

5.3.1.3  Evaluation matrix - coherence 

Evaluation question 

Assessment criteria 

Indicators 

Data analysis approach 

Data source / data collection 
methods 

EQ.11- To what extent is the SSD internally consistent and coherent 

11.1 To what extent is the SSD 
internally consistent and coherent 

The Directive is delivered in a 
coherent and simple manner 
with no requirements 
unnecessary, unclear, or 
contradictory 
A standalone Directive continues 
to be relevant 

List of elements in the Directives 
which are not internally 
coherent and their potential 
consequences 
Assessment of the completeness 
of the Directive as a self-
standing legislation 

Review of the objectives and 
provisions of the Directives 

Data from literature review 
Consultation and questionnaire 
analysis 
Public consultation 

EQ.12 - To what extent is the SSD coherent with other existing EU legislation such as the Urban Wastewater Treatment Directive (UWWTD), the Fertilising Products 
Regulation, Waste Framework Directive, the Water Framework Directives (and its daughter directives), the Marine Strategy Framework Directive, the Landfill 
Directive, the Nitrates Directive, Renewable Energy Directive, the Energy Efficiency Directive, Air Quality Directive, National Emissions Ceiling Directive, Industrial 

81 

 
 
 
Evaluation question 

Assessment criteria 

Indicators 

Data analysis approach 

Data source / data collection 
methods 

Emissions Directive, the REACH Regulation, General Principles of Food Law Regulation? 

12.1 Is the SSD coherent with the 
UWWTD? 

12.2 Is the SSD coherent with the 
Fertilising Products Regulation 
and other agricultural policies 
such as the Nitrates Directives? 

12.3 Is the SSD coherent with 
other waste legislation including 
the Waste Framework Directive, 
the Landfill Directive? 

12.4 Is the SSD coherent with 
chemicals legislation? 

The Directive and UWWTD are 
coherent, there are no 
weaknesses, gaps, overlaps or 
inconsistencies that may arise as 
a result of incoherence between 
these. 

The Directive and Fertilising 
Products Regulation and other 
agricultural policies are 
coherent, there are no 
weaknesses, gaps, overlaps or 
inconsistencies that may arise as 
a result of incoherence between 
these. 

The Directive and the waste 
legislation are coherent, there 
are no weaknesses, gaps, 
overlaps or inconsistencies that 
may arise as a result of 
incoherence between these. 

The Directive and wider 
chemicals legislation is coherent, 
there are no weaknesses, gaps, 
overlaps or inconsistencies that 
may arise as a result of 
incoherence between these. 

List of elements that may lead to 
weaknesses, overlaps or 
inconsistencies when 
considering the SSD and the 
UWWTD 

Qualitative analysis and 
comparison of the objectives 
and provisions of the SSD and 
the UWWTD 

Data from literature review 
Consultation and questionnaire 
analysis 
Public consultation  

List of elements that may lead to 
weaknesses, overlaps or 
inconsistencies when 
considering the SSD and the 
Fertilising Products Regulation 
and other agricultural policies 

Qualitative analysis and 
comparison of the objectives 
and provisions of the SSD and 
the Fertilising Products 
Regulation and other 
agricultural policies 

Data from literature review 
Consultation and questionnaire 
analysis 
Public consultation 

List of elements that may lead to 
weaknesses, overlaps or 
inconsistencies when 
considering the SSD and the 
waste legislation 

List of elements that may lead to 
weaknesses, overlaps or 
inconsistencies when 
considering the SSD and the 
wider chemicals legislation 

Qualitative analysis and 
comparison of the objectives 
and provisions of the SSD and 
the waste legislation 

Data from literature review 
Consultation and questionnaire 
analysis 
Public consultation 

Qualitative analysis and 
comparison of the objectives 
and provisions of the SSD and 
the wider chemicals legislation 

Data from literature review 
Consultation and questionnaire 
analysis 
Public consultation 

12.5 Is the SSD coherent with 
water and marine policies? 

The Directive and wider water 
and marine (WFD, MSFD, EQSD) 

List of elements that may lead to 
weaknesses, overlaps or 

Qualitative analysis and 
comparison of the objectives 

Data from literature review 
Consultation and questionnaire 

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Evaluation question 

Assessment criteria 

Indicators 

Data analysis approach 

Data source / data collection 
methods 

12.6 Is the SSD coherent with 
energy efficiency legislation? 

12.7 Is the SSD coherent with air 
quality and industrial emissions 
policies? 

legislation are coherent, there 
are no weaknesses, gaps, 
overlaps or inconsistencies that 
may arise as a result of 
incoherence between these. 

The Directive and energy 
efficiency legislation (Energy 
Efficiency Directive, Renewable 
Energy Directive) are coherent, 
there are no weaknesses, gaps, 
overlaps or inconsistencies that 
may arise as a result of 
incoherence between these. 

The Directive and air quality and 
industrial emissions policies (Air 
Quality Directives, National 
Emissions Ceiling Directive, 
Industrial Emissions Directive) 
are coherent, there are no 
weaknesses, gaps, overlaps or 
inconsistencies that may arise as 
a result of incoherence between 
these. 

inconsistencies when 
considering the SSD and the 
wider water and marine (WFD, 
MSFD, EQSD) legislation 

and provisions of the SSD and 
the wider water and marine 
(WFD, MSFD, EQSD) 
legislation 

analysis 
Public consultation 

List of elements that may lead to 
weaknesses, overlaps or 
inconsistencies when 
considering the SSD and energy 
efficiency legislation (Energy 
Efficiency Directive, Renewable 
Energy Directive) 

Qualitative analysis and 
comparison of the objectives 
and provisions of the SSD and 
energy efficiency legislation 
(Energy Efficiency Directive, 
Renewable Energy Directive) 

Data from literature review 
Consultation and questionnaire 
analysis 
Public consultation 

List of elements that may lead to 
weaknesses, overlaps or 
inconsistencies when 
considering the SSD and air 
quality and industrial emissions 
policies (Air Quality Directives, 
National Emissions Ceiling 
Directive, Industrial Emissions 
Directive) 

Qualitative analysis and 
comparison of the objectives 
and provisions of the SSD and 
air quality and industrial 
emissions policies (Air Quality 
Directives, National Emissions 
Ceiling Directive, Industrial 
Emissions Directive) 

Data from literature review 
Consultation and questionnaire 
analysis 
Public consultation 

EQ.13 - To what extent is the SSD coherent with wider EU policy?  

13.1 To what extent is the SSD 
coherent with wider EU policy 
(e.g., agricultural, trade)? 

The Directive and wider EU 
legislation are coherent, there 
are no weaknesses, gaps, 
overlaps or inconsistencies that 
may arise as a result of 
incoherence between the SSD 

List of elements that may lead to 
weaknesses, overlaps or 
inconsistencies when 
considering the SSD and related 
downstream legislation 

Qualitative analysis and 
comparison of the objectives 
and provisions of the SSD and 
related downstream 
legislation 

Data from literature review 
Consultation and questionnaire 
analysis 
Public consultation 

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Evaluation question 

Assessment criteria 

Indicators 

Data analysis approach 

Data source / data collection 
methods 

13.2 To what extent is the SSD 
coherent with the objectives of 
the EU Green Deal 

and related downstream 
legislation 

The Directive and the published 
and upcoming strategies and 
action plans are coherent, there 
are no weaknesses, gaps, 
overlaps or inconsistencies that 
may arise. 

Review of the objectives of the 
different action plans and 
strategies and identify points of 
synergies with the SSD 

Qualitative analysis and 
comparison of the objectives 
and provisions of the SSD and 
EU Green Deal policies 

Data from literature review 
Consultation and questionnaire 
analysis 
Public consultation 

EQ.14 - To what extent is the SSD coherent with international obligations 

14. 1To what extent is the SSD 
coherent with international 
obligations? 

The Directive and international 
legislation are coherent, there 
are no weaknesses, gaps, 
overlaps or inconsistencies that 
may arise as a result of 
incoherence between the SSD 
and considered international 
legislation (e.g., marine water 
conventions and SDGs) 

5.3.1.4  Evaluation matrix - relevance 

List of elements that may lead to 
weaknesses, overlaps or 
inconsistencies when 
considering the SSD and 
considered international 
legislation 

Qualitative analysis and 
comparison of the objectives 
and provisions of the SSD and 
considered international 
legislation 

Data from literature review 
Consultation and questionnaire 
analysis 
Public consultation 

Sub-questions 

Assessment criteria 

Indicators 

Data analysis approach 

Data sources/Data collection 
methods 

EQ.15 - To what extent is the SSD still relevant and does it correspond to the needs within the EU, in particular as regards the stated policy ambitions in the 
European Green Deal, as well as national ambitions as reflected in the observed changes in the national legislation and management of sewage sludge? 

15.1 What contribution has the  Monitoring data on 

Soil concentrations of named SSD 

MS reporting for infringement  MS monitoring data for both 

84 

 
 
 
 
Sub-questions 

Assessment criteria 

Indicators 

Data analysis approach 

SSD made to the correct 
management of sewage 
sludge, in particular 
minimising harmful effects to 
the soil, water (fresh & 
marine), vegetation, animals or 
man? 

concentrations of harmful 
aspects defined in SSD to 
demonstrate control or 
otherwise. 
Compliance data from MS to 
illustrate that SSD is enforced. 

substances are lower (heavy metals, 
pathogens etc) compared to pre-
implementation and 
neighbouring/similar non-EU 
geographies 

15.2 What new needs have 
been identified since the 
implementation of the SSD? 
And how are these needs 
managed within the existing 
SSD? 

Biological and chemical 
hazards to soil from sewage 
sludge are suitably controlled. 

Biodiversity indicators demonstrate 
no negative impacts from sewage 
sludge. 

Monitoring data for emerging 
substances does not exceed critical 
thresholds (DNELs). 

activities to demonstrate how 
successful SSD is at preventing 
contamination. 
Sludge and soil monitoring 
data generated under SSD. 
Literature review to similar 
geographies in non-EU 
countries as comparison (i.e., 
Ukraine, non-EU Baltic states, 
Turkey etc) 

Combination of three 
approaches:  
Review of national legislation 
to understand how and where 
it exceeds SSD and why? 
literature review to look at key 
emerging substances and 
whether the approach under 
SSD addresses them suitably; 
and 
stakeholder engagement to 
test the relevance of the SSD 
to modern demands. 

Data sources/Data collection 
methods 

sludge and soil, over time to 
show trends. 
Non-EU monitoring data as 
comparison. 
Data on infringement activities 
to demonstrate frequency of 
exceedances. 

Literature review for substances 
of greatest concern for sewage 
sludge. 
Stakeholder engagement to 
gather views on whether the 
SSD is suitably addressing the 
most relevant issues. 

15.3 Have new technologies / 
techniques emerged that 
supersede the approaches and 
requirements set out in the 
SSD? 

The scope of the SSD suitably 
covers all management 
options for sewage sludge. (in 
particular in light of the EU 
Green Deal, circular economy, 
and related planning) 

All identified management 
techniques for sewage sludge 
(especially related to agriculture) still 
fit within the SSD. 

Any new management techniques 
identified as having adverse effects 
for soil, vegetation, animals, or man. 

Combination of three things: 
Firstly, development of data on 
management techniques. 
Secondly comparison of SSD 
to all techniques identified. 
Literature review for reports, 
journal articles, grey data on 
any risks associated with new 
management techniques 

Industry data for management 
techniques. 
Policy analysis and comparison 
to SSD. 
Industry guidance on 
risks/managing negative issues. 
Stakeholder response on 
relevance of SSD for current 
practices. 

85 

 
 
 
 
Sub-questions 

Assessment criteria 

Indicators 

Data analysis approach 

Data sources/Data collection 
methods 

EQ.16 - Does the set of pollutants covered in the SSD still cover the most important pollutants in sewage sludge? If not, what are the missing pollutants in the SSD or 
pollutants that no longer need to be covered and why?  

16.1 Does the set of pollutants 
covered in the SSD still cover 
the most important pollutants 
in sewage sludge? 

There is clear feedback that 
the limit values and the 
pollutants covered by the 
Directive are relevant and 
correct. 

Assessment of the current limit 
values, the quality of the sludge and 
objectives of the Directive. 

16.2 What are, if any, the 
missing pollutants in the SSD 
or pollutants that no longer 
need to be covered and why? 

The national legislation does 
not cover additional 
parameters or pollutants 
The feedback received 
supports a view that the SSD is 
complete 

Assessment of the current limit 
values, the quality of the sludge and 
objectives of the Directive. 

Quantitative analysis of 
concentrations and limit 
values.  
Qualitative analysis of 
relevance of limit values. 

Quantitative analysis of 
concentrations and limit 
values.  
Qualitative analysis of 
relevance of limit values. 

data and information reported 
by Member States on 
implementation 
Collection of data and literature 
review 
Consultation and questionnaire 
analysis 

data and information reported 
by Member States on 
implementation 
Collection of data and literature 
review 
Consultation and questionnaire 
analysis 

EQ.17 - Has the initiative been flexible enough to respond to new issues and emerging risks (e.g., contaminants of emerging concern? Does the SSD contain moot or 
redundant stipulations? 

17.1 Has the initiative been 
flexible enough to respond to 
emerging risks (e.g., 
contaminants of emerging 
concern?  

There is scope for covering 
emerging pollutants as part of 
the Directive 

17.2 Has the initiative been 
flexible enough to respond to 
new issues? 

The Directive continues to be 
relevant facing new issues and 
opportunities 

List of the provisions relevant for 
emerging pollutants 
Analysis of these provisions and 
whether they are fit for the purpose 
of addressed emerging pollutants 

List the provisions of the Directive 
identified as being flexible 
Contribution of the Directive to the 
new issues in particular considering 
reuse of resources, nutrient 
recycling, and circular economy 

86 

Qualitative analysis of the 
Directive and evidence 
gathered  

Data from literature review 
Consultation and questionnaire 
analysis 

Qualitative analysis of the 
Directive and evidence 
gathered  

Data from literature review 
Consultation and questionnaire 
analysis 

 
 
Sub-questions 

Assessment criteria 

Indicators 

Data analysis approach 

Data sources/Data collection 
methods 

17.3 Does the SSD contain 
moot or redundant 
stipulations? 

All the provisions of the SSD 
are relevant and necessary 

List the provisions of the Directive 
identified as being flexible 

Qualitative analysis of the 
Directive and evidence 
gathered  

Data from literature review 
Consultation and questionnaire 
analysis 

5.3.1.5  Evaluation matrix – EU added value 

Sub-questions 

Assessment criteria 

Indicators 

Data analysis approach 

Data sources/Data collection 
methods 

EQ.18 – What is the added value of the Directive compared to what Member States could have reached without the Directive? 

18.1 What is the added value 
of the Directive compared to 
what Member States could 
have been reached without 
the Directive? 

18.2 What has changed 
regarding the SSD’s EU added 
value compared to its 2014 
evaluation study? 172 

Environmental impact of the 
sector; technological 
development in sewage sludge 
value chain; level playing field 

Views of stakeholders on benefits 
compared to the situation without the 
SSD 

Qualitative analysis of the extent 
that the changes in the 
production, treatment and use 
of sewage sludge be credited to 
the SSD 

Data from literature 
Consultation and questionnaire 
analysis 
Expert meeting 

The 2014 ex-post evaluation of 
the SSD did not examine its EU 
added value.  
The EU added value of the SSD in 
the 2014 evaluation is identified 
and compared with current 
implementation 

List of achievements credited to the SSD 
in the 2014 evaluation 
List of achievements credited to the SSD 
after the 2014 evaluation 

Qualitative analysis of the 
differences between the 
achievements of the SSD before 
and after the 2014 evaluation 

Data from literature 
Consultation and questionnaire 
analysis 
Expert meeting 

18.3 Are there any emerging 
risks that could hamper the 

Emerging risks are identified and 
are screened against the Directive 

List of emerging risks that can hamper 
the added value of the SSD 

Literature review of reports, 
journal articles, grey data on any 

Data from literature 
Consultation and questionnaire 

172 Please note, we include this sub-question to cover a requirement to consider changes, however we note the 2014 evaluation did not explicitly include an assessment of EU added value.  

87 

 
 
                                                 
SSD’s EU added value? 

Contribution of the Directive to 
addressing the identified issues 

risks associated with new 
approaches 
Qualitative analysis of the risks 
identified and the Directive’s 
approach to address them 

analysis 
Expert meeting 

EQ.19 – Have the various rules regulating sewage sludge set up by MS led to an unequal protection of human health and the environment across the EU, and if so to what 
extent? 

19.1 Have individual MS 
sewage sludge regulation 
rules led to unequal 
protection of human health 
and the environment across 
the EU, and if so, what is the 
extent of this difference? 

Varying environmental and health 
impacts in different MS resulting 
from different rules  

List of aspects related to human health 
and environmental protection that differ 
between MS and emerge due to sewage 
sludge regulation 

Quantitative analysis of 
environmental and health values 
across individual MS 
Qualitative analysis of the links 
of these values with the MS rules 

Data from literature 
Consultation and questionnaire 
analysis 

88 

 
 
5.4  1.2  Brief answers to the evaluation questions (EQs) and details of the evidence-base 

Effectiveness 

EQ. 1 & 3 - What progress has been made over time towards achieving the objectives and targets set out in the SSD in the various Member 
States? To what extent have the objectives been met? 

How effective has the implementation and enforcement of the SSD been in the 27 Member States and to what extent has this safeguarded 
agricultural soils from pollution? 

Answer: 

The use of sludge in agriculture has remained the main route for sludge management in the EU. Sludge has been widely and steadily used to the benefit 
of  agriculture,  leading  to  the  recovery  of  nutrients  from  2  to  3  million  tons  of  sludge  (which  is  also  waste)  per  year,  while  also  enhancing  the  soil 
structure, for the benefit and sustainability of the waste and the agricultural sectors.  

Overall, the level of heavy metals in sewage sludge used in agriculture has improved since the SSD came into force, which can be attributed to an extent 
to the action of the Directive. 

Limited information was identified linking overall agricultural soil quality and use of sewage sludge. 

Evolution of sludge use 

Depending on the source of data considered, sludge use in agriculture across the EU is estimated to lie between about 30 and 50%: 

Total agricultural use in literature 

29% and 50% 

Fragmented and different among each data source 

Sludge used in agriculture as a % of total sludge 
produced (2017)  

Quality of the data 

MS implementation report 

Eurostat 

30%  

29%  

Comprehensive in 2016-2018 

Comprehensive 2007-2016  
Limited insight in sewage sludge disposal 

89 

 
 
 
 
EurEau’s survey  

49.2% (4.5 million tonnes) 

Joint Research Centre (2020) 

37% (10 million tonnes) 

Unable to assess 

Unable to assess 

Table 1: Quantities of sludge used in agriculture according to different data sources 

Contribution of the SSD to sludge use in agriculture at national level  

Details on the analysis was made to group Member States in categories reflecting the impact that the SSD have had on the national practices related to 
management of sewage sludge, including its use in agriculture: data gathered were used in conjunction with other qualitative elements. 

Member States were grouped in categories reflecting the impact that the SSD has had on the national practices related to management of sewage sludge, 
including  its  use  in  agriculture.  Data  gathered  were  used  in  conjunction  with  other  qualitative  elements.  The  criteria  were  qualitatively  assessed  and 
included: 

- 

- 

- 

- 

the level of use of sewage sludge in agriculture at the time of adoption of the Directive: countries that already had an established practice of using 
sewage sludge were considered to be less influenced by the SSD, 
the adoption (or not) of  stricter requirements: countries that adopted more stringent requirements  were  considered to  be less  influenced by the 
SSD,  
the evolution of the use of sewage sludge in agriculture since adoption of the Directive: countries where the use of the sewage sludge markedly 
increased or decreased were considered to be more influenced by the SSD (assuming that a marked increase related to an enhancement of the use 
of sludge in agriculture, and that the Directive impedes the use of sludge when applicable limits cannot be met; noting the contradictory impact 
that the Directive had in both supporting in some Member States and hindering in others the use of sewage sludge, and 
the feedback from Member States’ competent authorities in the targeted consultation.173 

As be seen below, most of the Member States (14 out of 27) can be considered to have not been influenced in their national approach to sewage sludge 
management by the adoption of the SSD.  

173 Not all MS provided a response, see the synopsis report on consultation for more details. 

90 

 
 
                                                 
Assumed influence of the SSD per group of Member States on sewage sludge management practices 

Categories 

Member States 

Management practices of sewage sludge not or minimally influenced upon by the SSD  Austria, Belgium, Czechia, Denmark, Finland, France, Germany, Italy, Latvia, 

Luxembourg, Malta, Portugal, Slovenia, Sweden 

Management practices of sewage sludge highly influenced upon by the SSD 

Bulgaria, Estonia, Hungary, Ireland, Romania, Slovakia 

Management practices of sewages sludge moderately influenced upon by the SSD 

Croatia, Cyprus, Greece, Lithuania, Netherlands, Poland, Spain 

This analysis is supported by the feedback from  OPC expert respondents who were divided on the extent to which the changes in amounts of sewage 
sludge use in agriculture and the safety of its use in their country of residence can be attributed to the SSD and its transposition into (sub-)national law. 

EQ.2 - What factors have contributed to or hindered the achievement of the objectives and targets set out in the SSD? 

Answer: 

In addition to tighter limits at national level, a number of voluntary schemes of quality standards have been set up between stakeholders, increasing trust 
in  quality  of  the  sewage  sludge.  The  availability  of  sludge  of  relevant  quality,  the  support  that  sewage  sludge  provide  to  organic  matter  in  soil  have 
promoted  the  use  in  agriculture  too.  The    implementation  of  the  waste  framework  Directive  probably  influcenced  too,  as  it  promotes  the  recovery  of 
waste  over  final  disposal  (e.g.  landfilling).  Conversely,  factors  hindering  the  achievement  of  the  objectives  have  included  public  perception  of  risks 
associated with sewage sludge, the lack of harmonised EU-wide end-of-waste criteria for sewage sludge for agricultural land application, the competition 
for  agricultural  use  with  other  organic  waste  (e.g.  manure  or  biowaste),  and  other  uses  of  sewage  sludge  (e.g.  for  land  reclamation,  remediation  or 
landscaping). 

EQ. 4&5 What have been the (quantitative and qualitative) effects of the SSD? What have been the unintended/unexpected effects of the SSD? 

Answer: 

Additional positive effects include the increased interest knowledge related to sludge. Application of sludge onto farmland also seems to have an overall 
negative carbon footprint. 

Negative unintended effects include the presence of antimicrobial genes in the soil, possible emissions of methane, as well as from other contaminants 
which it can contains and which are not regulated by the Directive. More research is needed to figure out whether and to which extent those elements do 
actually pose a risk to the environment and the human health. 

91 

 
 
Efficiency 

EQ.6 &7 To what extent has the SSD been cost-effective? Are the costs related to the SSD proportionate to the benefits? To what extent do the 
requirements of the SSD influence the efficiency with which the observed achievements have been attained? What other factors influence the 
costs and benefits? 

It  is  very  difficult  to  estimate  the  overall  costs  and  benefits  of  the  implementation  of  the  Directive.  But  it  is  shown  that  the  application  of  sludge  to 
agricultural land is significantly less costly than other options for use of sewage sludge. This is particularly true in comparison with (mono-)incineration, 
which is the main alternative to the use of sludge in agriculture. Costs and negative externalities of alternative options for sludge management are also 
comparable to those of use in agriculture.  

Given the high dependency of sludge management  to  local  conditions,  and the heterogeneity of  such conditions  across Member States and regions or 
municipalities, the enabling rather than prescriptive nature of the Directive has provided a framing which has allowed, in principle, for efficient decision-
making at national and regional level. 

Costs and benefits for different sludge treatment options and P-recovery technologies  

Assumptions for the calculations: 

-  Water content of sewage sludge : Wet sludge : < 5 % DS ; Dewatered sludge : 25% DS ; Dried sludge : > 85 % DS 
-  Labour  cost:  29  €/man*h  (great  differences  in  Europe  ranging  from  7-42  €/man*h).  This  has  an  effect  on  labour  intense  processes  as  e.g. 

composting (1/3 of costs are associated to labour) 

-  Economy of scale : Calculations were performed for plants with different treatment capacities (small, medium, large) whereby for e.g. a small 

composting plant has a capacity of 15.000 t input and a small mono-incineration plant has 70.000 t input/year. 

-  All cost without revenues 

92 

 
 
 
 
Table 2: Overview of costs linked to sludge management (treatment, transport, recovery and disposal of sludge) 

Sludge treatment at the WWTP 

Cost range, €/t DM 

Year 

Country 

Source 

Anaerobic digestion  
(at the WWTP) 

Mechanical dewatering 

Solar drying 

Thermal drying 

(20-50)-200 
130-5101 

220-300 
75-180 
180-240 

125-200 
270-360 

189 
255-715 
150-500 
250-310 (with gas) 
220-360 

- 

2016 
- 

- 
2018 

2015 
2016 
- 
- 
2018 

Germany 
- 
Germany 

- 
Germany 

Italy 
Slovenia 
- 
- 
Germany 

Stakeholder consultation 
JRC 

INECTUS, 2016 ; 
JRC 
Source open 

JRC ; 
Roskosch et al., 2018174 

Diaz, Gracia and Canziani, 2015 ; 
Bratina et al., 2016 ; 
Stakeholder consultation 
JRC 
Roskosch et al. 2018 

Sludge management option agriculture 

Cost range, €/t DM 

Year 

Country 

Source 

Agricultural use  
(wet sludge) 

Agricultural use (dewatered sludge) 

200-320 
100-175 

125-175 
80-150 

2018 
2021 

2018 
2021 

Germany 
Austria 

Germany 
Austria 

Roskosch et al., 2018 ;  
Amann et al. 2021 

Roskosch et al. 2018;  
Amann et al. 2021 

174 Roskosch, A., Heidecke, P., Bannick, C.G., Brandt, S., Bernicke, M., Dienemann, C., Gast, M., Hofmeier, M., Kabbe, C., Schwirn, K., Vogel, I., Voelker, D., Wiechmann, B., 2018.  Sewage sludge 

management in Germany. Umweltbundesamt (UBA), Dessau-Roßlau, Germany. 

93 

 
 
                                                 
 
 
 
Composting (all technologies) 

Composting (open windrow, simple technology) 

Composting (closed windrow, advanced technology e.g. 
exhaust gas treatment) 

100-500 
125-280 
150-300 

125-230 

155-350 

2002 
2021 

EU 
Austria 

- 

- 

- 

- 

Stakeholder consultation 
Eunomia, 2002 ; 
Amann et al. 2021 

JRC 

JRC 

Co-Incineration 

-  Waste to energy plant 

-  Coal industry 

-  Cement industry 

Mono-incineration 

Landfill2 (in countries with 0 or <5% sewage sludge 
landfilling) 

280-370 (dew. sludge) 

2012, 2021 

Germany 

Wiechmann et al., 2012 

200-300 (dew. sludge) 
120 (dried sludge) 

180-220 (dew. sludge) 
80-110 (dried sludge) 

260-400 
280-480 

250-280 
40-620  
(median 230) 

2012, 2014 

Germany 

2012, 2014 

Germany 

- 
2018 

- 
2002, 2013 

- 
EU 

Wiechmann et al., 2012 
Montag et al., 2014 

Wiechmann et al., 2012 
Montag et al., 2014 

JRC ;  Roskosch et al., 2018 

JRC ; Eunomia, 2002 ; EEA, 2013 

Landfill2 (in countries with >5% sewage sludge landfilling)  15-360  

2002, 2013 

EU 

Eunomia, 2002 ; EEA, 2013 

(median 90) 

Transport 

Transport (truck capacity unknown) 

Transport (truck, 30 t) 

Cost range, €/t DM 

0.3 €/km 
1.3-1.6 €/km 
1.5 €/km (1.2 €/km : Eastern 
Europe, 1.8 €/km : Western 

Year 

2016 

2018, 2021 

Country 

Source 

 Italy 
Slovenia 
Germany ; 
EU 

Diaz, Gracia and Canziani, 2015 
Bratina et al 2016  
BME, 2018 ;  
The Ti et al., 2021 

94 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Transport with truck (15 km, 30 t capacity) 
Transport with tractor and trailer (15 km, 14 t capacity) 

Europe) 
3-4 (dewatered sludge) 
60-70 (wet sludge) 
8-10 (dewatered sludge) 

JRC 
JRC 
JRC 

1 cost for WWTP with capacities from 20.000 to 500.000 population equivalent (for small WWTP anaerobic digestion is very expensive) 
2 with country specific landfill tax 

Potential savings:  

-  E.g. Reduced disposal costs for a mono-incinerators if SSA is used in fertiliser industry or by recycling facility operators 

Potential revenues (examples): 

-  Energy 

o  CHP of biogas from anaerobic digestion: Electricity: ~65 €/t DM; Heat: ~80 €/t DM 
o 

Incineration of sewage sludge: ~ 75 €/t DM (Electricity: ~20 €/t DM; Heat: ~55 €/t DM 

-  Compost: 2-10 €/t compost 

Examples of costs in Austria and Spain175 

175 NB : also taken into account to derive the figures provided Table 2 above 

95 

 
 
                                                 
 
 
Cost range for different sludge treatment options incl. transport and product 
revenues 

Assumptions: 
Labour cost: 

  Labour cost per hour in Austria:  
  Labour cost per hour in Spain:  

Percentual share of labour cost of the sludge processes: 

  Agriculture:  
  Composting external plant: 
  Co-incineration:   
  Mono-incineration: 
  P-recovery: 

37 €/h 
23 €/h 

30% 
32% 
5% 
10% 
5% 

Transport distances, truck load and transport cost: 

  Agriculture:  
  Composting external plant: 
  Compost to agriculture: 
  Co-incineration:   
  Mono-incineration: 
  P-recovery: 
plant) 

15 km 
50 km 
15 km 
120 km 
200 km 
0 km (located at the incinerator 

  P-recovery products to end-user 
  Truck load:  
  Transport cost Austria: 
  Transport cost Spain: 

50 km 

25 t/load 
1.8 €/km 
1.6 €/km 

Revenues: 

  Compost:  
  P-recovery: 

for a WWTP) 

  Energy:   

Investment costs: similar 

8 €/t DM 
262 €/t DM (includes Calciumphosphate, FeCl / AlCl 

none so far 

Additional cost for the shift from direct agricultural  sludge use to other sludge treatment processes 

Shift from1: 
direct agri to composting and then agri 
direct agri to co-combustion (cement) 

Austria 
+102 % 
+97% 

96 

Spain 
+100 % 
+115% 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
direct agri to co-combustion (WtE) 
direct agri to mono-inc 
direct agri to mono-inc and P recovery 

co-inc (cement) to mono-inc (and P-recovery) 
co-inc (WtE) to mono-inc (and P-recovery) 

1based on the average values of the sludge processes 

+201% 
+225% 
+309% 
(if rec. technology is economic  +225%) 
+65% (+108%) 
+8% (+36%) 

+230% 
+249% 
+342% 
(if recovery technology is economic  +249%) 
+62% (+106%) 
+5% (+34%) 

Comparison of nutritive properties of sludge and other types of fertilisers 

EQ.8  Are there opportunities to simplify the legislation or reduce unnecessary regulatory costs without undermining the intended objectives of 
the intervention? 

Answer: 

97 

 
 
 
 
 
No such opportunity was identified 

EQ.9  Are there significant differences in costs (or benefits) between Member States, and if so, what are the underlying causes? How do these 
differences link to the SSD? 

Answer: 

Sludge management is very highly dependent on local conditions (e.g. climate, size of dwellings, availability of land, quality of soil and of sludge) and 
there  are  considerably  different  situations  across  different  Member  States  and  regions.  Treatment  equipment  costs,  one  the  major  source  of  costs,  are 
reported to be rather uniform across the EU. Operating (including energy) and labour costs, on the other hand, vary a lot across countries. Another source 
of cost  is  the transport of the sludge from the UWWTP to  the agricultural land (or  from  the UWWTP to  other means of  disposal  if the sludge is  not 
suitable for farmland use) which also obviously depends on distances local situations. 

EQ.10 How timely and efficient is the process for reporting and monitoring 

Answer: 

There  is  room  for  improvement  on  reporting:  there  are  significant  data  gaps  and  inconsistencies  in  reporting,  including  in  the  reports  provided  by 
Member States under this Directive and other reporting systems, notably the UWWTD. The reporting system also only allows to assess the effectiveness 
of the Directive to an extent. This will be improved when new reporting requirements start to apply, as of 2023, making spatial data on the application of 
sludge available. 

Details for the estimation of administrative costs: 

Estimate for administrative costs were identified in the literature review supplemented with very few estimates provided by stakeholders as part of the 
consultation.  

The fitness check of environmental reporting and monitoring176 (later referred to as ‘fitness check’) provides a global estimate of the administrative costs 
from the implementation of European legislation. Its estimate covers usefulness, double reporting, frequency of reporting, and estimates that the annual 
administrative burden attributable to reporting and monitoring obligations associated with the SSD to be between €30 000 – 100 000 p.a. It should be 

176 European Commission. (2017). Actions to Streamline Environmental Reporting. Retrieved August 6, 2021, from 
https://ec.europa.eu/environment/legal/reporting/pdf/Reporting%20and%20monitoring/support_fitness_check_report_annexes.pdf 

98 

 
                                                 
noted that this cost is not specific to the SSD, but it is an estimation based upon the administrative burden of a group of 17 regulations, of which the SSD 
is part. 

Considering reporting costs more specifically, according to the EC 2017 Fitness Check, the reporting obligations of the SSD are estimated to require 20 
days per MS to copy information which is already available / in own legislation or through data collection necessary for other purposes. It is estimated 
that the EC would require 40 days to collate information from 28 MS. These actions were repeated every three years  177 and will be repeated annually 
further to the introduction of Regulation 2019/1010 on the alignment of reporting obligations in the field of legislation related to the environment. The 
costs outlined here are specific to the costs borne as a result of the SSD, although detail as to the exact nature of these costs has not been provided. The 
SSD evaluation questionnaire has received 14 responses to the question on the cost of reporting requirements associated with the SSD. Of these, 12 MS 
CA suggested that they do not hold this information, one respondent stipulated “none” and another respondent provided an estimate of 3 days p.a., which 
would amount to a cost of around €500 per year178. While this figure is considerably below the fitness check estimate above, it is not clear whether this 
estimate is representative for the EU27.  

With regards to the enforcement costs of the SSD, 13 answers were received to the relevant question of the Member State questionnaire. Of these, 12 
stipulated that such information is not available and one provided information on costs associated with the implementation of the SSD (presented below).  

From the consultation of stakeholders, two quantitative estimates were provided: 

-  One respondent indicated that the enforcement costs of the SSD (without describing the scope of the activity under ‘enforcement’) was equating to 

two full-time equivalent staff for an average competent authority ; 

-  One respondent indicated that reporting costs specifically for the SSD were 3 days per annum, which amounts to a cost of around €500 per year (as 

above). 

177 European Commission. (2017). Actions to Streamline Environmental Reporting. Retrieved August 6, 2021, from 
https://ec.europa.eu/environment/legal/reporting/pdf/Reporting%20and%20monitoring/support_fitness_check_report_annexes.pdf 
178 EUR 487 per year, assuming an 8 hour day and a cost per hour of €20.3 as reported in Eurostat dataset LC_LCI_LEV, weighted average data for EU27(2020) for the sector “Administrative and Support 

Service Activities.” 

99 

 
                                                 
We  calculated  an  estimate  for  overall  administrative  costs   based  on  the  information  identified,  of  €77,000  –  80,000179  per  year  per  Member  State180. 
While  based  on  very  scarce  data,  this  estimate  is  within  the  range  of  the  estimate  calculated  under  the  Fitness  Check.  It  is  important  to  note  that 
administrative costs depend on country size or national versus regional structure of approval systems in place. 

The estimate represents the sum of the enforcement and reporting costs identified to form a general administrative cost and uses the following data: 

-  The lower end of the range represents possible administrative costs using the two full time equivalent staff on enforcement and the 3 days per annum 

reported by one stakeholder on reporting 

-  The upper range uses the two full time equivalent staff on enforcement and the 20 days estimate from the fitness check on reporting  

Beyond competent authorities, water operators have employees in charge of managing the administrative costs associated with approving the spreading of 
sewage sludge on agricultural land. Separating the part related to the SSD from other national requirements (covering other legislation) is not possible181. 
One wastewater operator suggested a cost of €250,000 per year and others explained that the costs are exacerbated by lengthy land application approval 
processes, with reported delays between 10 months and years. However, it is unequivocal that the costs reported by the operators are linked to national 
requirements, many of which exceed those of the SSD. 

No information on administrative costs to farmers has been identified as part of the study process, including the stakeholder consultation. 

As  such,  total  administrative  costs,  including  implementation,  reporting  and  enforcement  by  national  and  regional  competent  authorities,  wastewater 
operators and farmers are likely to reach figures of hundreds of thousands to millions Euro per Member State per year. Separating the costs of national 
legislation and SSD implementation and enforcement is not possible. 

Coherence 

EQ.11 - To what extent is the SSD internally consistent and coherent? 

Answer: 

179 The upper range includes the 20 day administrative estimate which equates to around €3,200 in costs per MS per year. 
180 This is based on the labour cost of €20.3/hour, as per footnote Error! Bookmark not defined. and on the assumption of 8-hour days and 47 working weeks per year; Glossary: Labour force survey (

LFS) - Statistics Explained (europa.eu), Statistics | Eurostat (europa.eu) 

181 Interview with wastewater operator and multiple targeted stakeholder questionnaire responses. 

100 

 
                                                 
The Directive is found internally coherent, broadly speaking, but its internal market legal base is arguable. 

EQ.12, 13, 14 - To what extent is the SSD coherent with other existing EU legislation, with wider EU policy and with international obligations? 

Answer: 

The Directive works coherently and in synergy with the general policy and regulatory framework it fits in, notably with environmental legislation and 
initiatives set under the Green Deal and Circular Economy Action Plan. 

However, for sludge management, there can be trade offs between objectives of zero pollution, waste and nutrient recovery, energy recovery and climate 
change mitigation. 

Coherence with the EU Green Deal and its sector specific policies 

The  European  Green  Deal182  is  the  EU  action  plan  to  make  its  economy  sustainable  and  make  EU  the  first  climate-neutral  continent  by  2050.  In 
particular, it sets  policy  goals  for an efficient  use of resources, for a just and inclusive transition towards a clean and circular economy.  It  sets  policy 
objectives for different policy areas that have relevance to sewage sludge use, including sustainable agriculture, biodiversity, pollution, and clean energy.  

The SSD can contribute to the policy areas covered by the EU Green Deal: 

Coherence with the Circular Economy Action Plans 

In 2015, the European Commission adopted its first circular economy action plan183. It included measures to help stimulate Europe's transition towards a 
circular economy, boost global competitiveness, foster sustainable economic growth and generate new jobs. The 54 actions established by the plan have 
been implemented, with measures covering the whole life cycle: from production and consumption to waste management and the market for secondary 
raw  materials  and  a  revised  legislative  proposal  on  waste.  A  significant  number  of  these  measures  are  very  relevant  to  the  Sewage  Sludge  Directive, 
although the latter was not specifically mentioned in the Plan. They included: 

-  developing quality standards for secondary raw materials where they are needed (in particular for plastics), and improving rules on 'end-of-

waste'. 

182 (2019) Communication from the Commission to the European Parliament, the European Council, the Council, the European Economic and Social Committee and the Committee of the Regions: The 

European Green Deal  

183 COM(2015) 614 final - Closing the loop - An EU action plan for the Circular Economy 

101 

 
                                                 
- 

the revised EU regulation on fertilisers, to facilitate recognition of organic and waste-based fertilisers in the single market and thus support the 
role of bio-nutrients in the circular economy. 
the legislative proposal on reused water 

- 
-  options on the interface between chemicals, products and waste legislation, including on how to reduce the presence and improve the tracking 

of chemicals of concern in products. 

The new circular economy action plan (CEAP)184 was adopted in March 2020, as one of the main building blocks of the European Green Deal. It is also a 
prerequisite to achieve the EU’s 2050 climate neutrality. It sets out new initiatives for EU’s further transition to a circular economy, to reduce pressure on 
natural  resources  and  create  sustainable  growth.  The  new  action  plan  announces  initiatives  along  the  entire  life  cycle  of  products,  promoting  circular 
economy processes, waste prevention and the preservation of the resources in the EU economy, with a notable focus on food and nutrients. 

By promoting safe resource re-use and nutrient recovery, the SSD concurs to the objective of the Circular Economy Action Plan: it promotes the re-use 
and recycling of a waste material (sewage sludge), and thereby re-use of primary phosphorus, nitrogen and organic matter, while also contributing to the 
EU’s strategic aim to reduce its dependency on nutrients from third countries. 

The  CEAP  actually  specifically  refers  to  the  SSD.  It  foresees  that  the  Commission  would  consider  reviewing  directives  on  wastewater  treatment  and 
sewage  sludge.  In  the  context  of  the  on-going  UWWTD  review,  now  on-going,  it  also  specifies  that  this  review  should  work  in  synergy  with  this 
evaluation, and help increase the ambition level to remove nutrients from wastewater and make treated water and sludge ready for reuse, supporting more 
circular, less polluting farming. Steps will be taken towards energy efficiency and carbon neutrality as well as a better application of the ‘polluters pays’ 
principle. The  CEAP also  calls  for the UWWTD  review to look at improving access  to  sanitation for all and  to  information.  It  also  demands that the 
review should support the concrete implementation of the future Integrated Nutrient Management Plan (INMAP), which is one of the actions of the 
CEAP185. 

The  Integrated  Nutrient  Management  Plan  (INMAP)  will  seek  to  ensure  more  sustainable  application  of  nutrients  and  stimulating  the  markets  for 
recovered  nutrients.  The  action  will  include  looking  at  the  indicators  and  tools  for  monitoring  to  improve  assessment  and  comparability,  and  at  best 
practice sharing to increase effectiveness. This will feed into an integrated assessment of nutrient pollution and progress tracking, e.g. through the Zero 
Pollution Monitoring and Outlook reports. The action plan will aim to focus the efforts of Member States on nutrient pollution hotspots in order to reduce 
pollution effectively and minimise the gaps to targets. It will also look at creating tools to improve application of environmental and climate legislation in 

184 New circular economy action plan (CEAP) 
185 To be updated -  

102 

 
                                                 
full.  It  will  aim  to  maximise  synergies  with  the  common  agriculture  policy,  making  best  use  of  the  new  green  architecture.  The  holistic  approach 
proposed will also contribute to achieving targets for non-CO2 emissions from the agriculture sector, as proposed in the ‘Fit for 55’ package186. Action 
may  range  from  regulatory  initiatives,  including  evaluating  and  revising  legislation  (if  necessary)  and  complementing  legislation  to  achieve  a  more 
holistic  approach  to  nutrient  pollution,  to  non-regulatory  initiatives  facilitating  cross-sectoral  approaches  and  drawing  on  technological  developments. 
The requirement of accounting of nutrient needs of the plants before authorising the application of sewage sludge, including its amount, also contribute to 
the INMAP. This latter obligation ensures that waste is recovered only to the amounts that are strictly necessary for plant needs, and prevents leachate 
(that  is,  loss, and a risk of pollution by eutrophication).  However, as  was seen  in  the analysis of the Effectiveness  of the Directive, the SSD does not 
foresee means to ensure that this principle is respected.  If it were not, then sludge use in agriculture would, not, in operational and (compliance) terms, 
be fully consistent with recovery objectives and could be seen as a disposal operation in practice.  

Among  nutrients,  Phosphorus  is  to  be  emphasised:  it  is  also  included  in  the  list  of  critical  raw  materials  which  the  EU  has  created  to  reduce  its 
dependency  on  materials  of  high  importance  to  the  economy,  when  there  is  high  risk  of  short  or  discontinued  supply.  The  importance  of  phosphorus 
recycling is also emphasised by the European Economic and Social Committee consultative communication on the sustainable use of phosphorus187. It 
highlights  the  value  of  cutting  the  use  of  primary  phosphorus,  increasing  the  use  of  organic  matter,  and  recycling  substances  rich  in  phosphorus,  but 
currently classified as waste, such as sewage sludge188.  Phosphorus can be derived from sludge not only through direct application onto farmland, but 
also  through  its  incineration  of  sludge.  In  this  way  it  comes  out  in  a  form  which  competes  with  the  organic  form  found  in  sewage  sludge  and  very 
precious for the phosphate industry: it can enter in the composition of industrial fertilisers and have more efficient nutritious properties for plants, or be 
used for many other applications in the phosphate industry. In this way sludge application onto land competes with incineration, which creates a lack of 
coherence with the SSD. 

The OPC results showed that of 171 respondents, 36% (61) agreed or strongly agreed that the SSD is coherent with the Circular Economy Action Plan. A 
share of 31% disagreed or strongly disagreed that the SSD is coherent and 12% were neutral. Others did not know or had no opinion (22%). 

Stakeholder views on coherence with the Green Deal: 

186 https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:52021DC0550 

187 Opinion of the European Economic and Social Committee on the ‘Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the 
Committee of the Regions — Consultative communication on the sustainable use of phosphorus’.  
188 TRENECON. (2021). Preparatory study on sewage sludge management in the Danube Region 

103 

 
                                                 
 
From the 171 respondents to the OPC, 28% agreed that the SSD is coherent with the EU Green Deal, while 33% disagreed and 12% were neutral189.  

MS targeted consultation evidenced that 33% out of 18 respondents agreed that the SSD is coherent with the European Green Deal, 22% were neutral, 
17% disagreed190.  

The targeted consultation with stakeholders evidenced that 44% out of 41 respondents agreed that the SSD is coherent with the European Green Deal, 7% 
were neutral, 30% disagreed.191  

Similar patterns of responses were provided when more specifically considering the coherence of the SSD with the different deliverables of the Green 
Deal,  apart  from  the  following:  MS  tended  to  disagree  that  the  SSD  is  coherent  with  the  soil  strategy,  and  targeted  stakeholders  tended  to  disagree 
regarding its coherence with the Farm-to-Fork strategy. Respondents from the OPC also tended to agree on the coherence with the methane strategy. 

Coherence with legislation related to water and air pollution 

Water Framework Directive 

The WFD is the main instrument for the EU water policy, it aims to get polluted waters clean again, and ensure clean waters are kept clean. It uses a 
combined approach of emission limit values not to be exceeded, pollution sources and quality standards to be achieved for waters. Since the SSD was 
adopted with a view to the protection of agricultural land and human health as a result of use of crops grown on such land and since it was adopted long 
before  Union  policy  was  developed  for  the  protection  of  water  environment,  it  does  not  include  explicit  objectives  or  measures  aiming  to  prevent 
negative impact on water as it does for soil pollution. However, the parameters and the limit values it sets for use of sludge on agricultural land contribute 
to restricting pollution of water as a result of sewage sludge runoff or penetration to groundwater. The new spatial data reporting could help identify the 
sources of pollution if linked to sewage sludge application. 

The  Nitrates  Directive192  (ND)  aims  at  reducing  water  pollution  derived  from  nitrates  of  agricultural  origin  and  further  preventing  such  pollution.  It 
requires Member States to identify risk areas and to develop action programmes accordingly, to control fertiliser (including sewage sludge) application. 
The two Directives are coherent in their objectives of protecting the soil and surface and ground water and are complementary to each other since the 
SSD does not address the specific concerns of vulnerable areas that may be linked to agricultural soil areas as a result of nitrogen application. However, 

189 Others did not know/no opinion (27%). 
190 Others did not know/no opinion 
191 Others did not know/no opinion 
192 Directive 91/676/EEC.  

104 

 
                                                 
the SSD requires the quantity of nitrogen to be analysed as part of the tests to be performed on sludge; thereby also contributing to limiting the risk of 
excessive  fertiliser  application  that  may  result  in  pollution  since  high  quantities  of  sewage  in  water  bodies  can  cause  eutrophication.  Therefore,  a 
balanced application of fertiliser is required both by the ND and SSD.193 For the purposes of environmental protection, the implementation of ND may 
result in a decrease in the amount of sewage sludge applied on land in areas identified as at risk194,195. The new reporting requirements for spatial data for 
the SSD could help further identify the sources of pollution if linked to sewage sludge application. 

Stakeholders generally agree on the coherence between the SSD and the Water Directives. 

The coherence of the Directive with other legislation, related to water and air196, as well as with the National Emissions Ceilings and the Industrial 
Emissions Directive, was also assessed. Details are provided in Annex III. In brief, these legislative instruments, aiming at protecting water and air from 
pollution, work in synergy with the SSD. They can be seen as completing it in a way, as it is not explicit in its environmental objectives or measures to 
ensure safeguarding of the air and water environments. The parameters and the limit values it sets for use of sludge on agricultural land contribute to 
restricting pollution of water as a result of sewage sludge runoff or penetration to groundwater. This coherence would be strengthened if the measures set 
by  the  SSD  were  shown  sufficient  to  protect  the  environment  and  health,  which  cannot  not  be  fully  demonstrated,  as  discussed  in  section  4.1.1  on 
effectiveness. Also, a number of these legislative instruments are in the process of being revised, therefore any follow-up to this evaluation will need to 
take that into account. 

A  number  of  laws  and  policy  initiatives  contribute  to  prevention  of  pollution  by  hazardous  substances  at  the  source,  indirectly  helping  to  reduce  the 
amount of contaminants  present in sludge.197 It is noteworthy to mention the link with the  Chemicals Strategy  for Sustainability towards a Toxic-Free 
environment198 and the REACH Regulation199. The REACH Regulation, by regulating the use of chemicals used in products that may enter wastewater 
systems  and  consequently  in  sewage  sludge,  contributes  to  reducing  the  levels  of  hazardous  substances  (including  heavy  metals)  contained  in  sludge, 
therefore  complementing  the  SSD  and  leading  to  an  increased  confidence  in  sludge  users.200  In  addition,  one  of  the  key  actions  to  be  taken  by  the 

193 SWD(2019) 439 final of 10.12.2019.  
194 Milieu Ltd; WRc; RPA. (2010). 
195 SWD(2019) 439 final of 10.12.2019. 
196 The Water Framework Directive, the Directives on groundwater, on the marine environment (and the UWWTD, discussed earlier on). More details are provided in Annex III EQs-12-14. 
197 These, inter alia, include the REACH Regulation (EC) No 1907/2006, European Union Strategic Approach to Pharmaceuticals in the Environment (COM(2019)128 final of 11.3.2019), A European 
Strategy for Plastics in a Circular Economy (COM(2018)028 final of 16.1.2018), and product related legislation like the Commission proposal for a Eco-design for Sustainable Product Regulation and 
the upcoming initiative on microplastics. 

198 COM(2020)667 final of 14.10.2020. 
199  Regulation (EC) No 1907/2006 of 18 December 2006 concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals 
200 Milieu Ltd; WRc; RPA. (2010) 

105 

 
                                                 
Commission under the Chemicals Strategy for Sustainability is the restriction of PFAS under REACH for all non-essential uses201. Further regulation of 
PFAS  substances  are  also  considered  under  other  Union  waster  policy  legislation  to  monitor  and  control  pollution.202  As  addressed  in  section  3.3  on 
relevance, PFAS, so-called “forever chemicals” due to their persistence in the environment, count among contaminants in sludge; therefore any follow-up 
to this evaluation will need to take into account such developments to ensure consistency and a holistic approach across different policy frameworks; this 
has also been supported by the stakeholders.  

As part of the European Green Deal, the EU is currently revising the Air Quality Directive, by aligning the EU quality standards with scientific evidence, 
improving  the  legislative  framework,  and  strengthening  air  quality  monitoring,  modelling,  and  plans203.  The  coherence  of  the  SSD  will  have  to  be 
considered with regard to the revised legislation. 

The OPC results showed that of 164 respondents, 15% (24) agreed or strongly agreed that the SSD is coherent with the IED. A share of 15% disagreed or 
strongly disagreed that the SSD is coherent and 26% were neutral. The remaining (and the most) respondents reported that they did not know/no opinion 
(45%).  

The literature review and OPC did not highlight elements of incoherence between the SSD and the Industrial Emission Directive. 

Relevance 

EQ.15, 16, 17 - To what extent is the SSD still relevant and does it correspond to the needs within the EU, in particular as regards the stated 
policy ambitions in the European Green Deal, as well as national ambitions as reflected in the observed changes in the national legislation and 
management of sewage sludge? 

Does the set of pollutants covered in the SSD still cover the most important pollutants in sewage sludge? If not, what are the missing pollutants 
in the SSD or pollutants that no longer need to be covered and why? 

Has  the  initiative  been  flexible  enough  to  respond  to  new  issues  and emerging  risks  (e.g.,  contaminants  of  emerging  concern)?  Does  the  SSD 
contain moot or redundant stipulations? 

201 COM(2020) 667 final of 14.10.2020.  
202 Directive on Environmental Quality Standards (Directive 2008/105/EC), the Groundwater Directive 2006/118/EC and Directive on drinking water (EU) 2020/2184. 
203  European  Commission  -  (2020).  Revision  of  the  Ambient  Air  Quality  Directives.  https://ec.europa.eu/info/law/better-regulation/have-your-say/initiatives/12677-Revision-of-EU-Ambient-Air-Quality-

legislation  

106 

 
                                                 
The objectives of health and environmental protection and of nutrient recovery of the SSD remain of utmost relevance. Under the Green Deal, sludge 
management is at the intersection of several Union policies, notably circular economy and Union industrial policy which promotes nutrient recovery and 
the Union’s strategic independence on mineral fertilisers and policies for attaining zero pollution, climate neutrality and energy independence. 

The  limits  set  for  heavy  metals  by  the  Directive  and  the  set  of  pollutants  which  it  covers  would  need  review,  to  potentially  cover  other  organic 
contaminants.  Further  screening  of  contaminants,  notably  contaminants  of  emerging  concern,  is  needed,  to  assess  whether  the  set  of  contaminants 
covered by the Directive should be broadened, based on risk assessments as appropriate. 

The Directive has remained flexible, allowing Member States to adopt stricter requirements and adopt sludge management policies or practices adapted 
to local situations. Some Member States are moving away from sludge use in agriculture, to take advantage of other uses which can be made of sludge. 

EU added value 

EQ.18 &19 - What is the added value of the Directive compared to what Member States could have reached without the Directive? 

Have the various rules regulating sewage sludge set up by Member State led to an unequal protection of human health and the environment 
across the EU, and if so to what extent? 

The  Directive  has  provided  a  framework  for  safe  use  of  sludge  in  agriculture  at  EU  level,  setting  minimum  standards  for  environmental  and  health 
protection, bringing benefits  of transboundary nature.  However, the  Directive has a limited influence on sludge management in  some Member  States. 
Requirements differ across Member States, but further assessment would be needed to establish whether this has lead to unequal environment and health 
protection across the EU. 

107 

 
 
 
 
 
 
ANNEX IV. OVERVIEW OF BENEFITS AND COSTS  

108 

 
 
 
Table 1. Overview of costs and benefits identified in the evaluation 

Cost of sludge (pre-)treatment and transport before land application 

Citizens/Consumers  

Wastewater operators 

Administrations 

Farmers 

Quantitative  

Comment  Quantitative  

Comment 

Quantitative 

Comment  

Quantitative 

Comment 

Direct financial cost  Recurrent 

Potentially a share 
of this amount, 
indirectly 

Dependin
g on the 
financing 
structure 
of water 
and 
sanitation 
services. 

EUR 120– 
210/ tDM 
(or a share of 
this, see 
comment) 

Depending on 
the financing 
structure of 
water and 
sanitation 
services.  

Potentially a 
share of this 
amount, 
indirectly 

Depending on 
the financing 
structure of 
water and 
sanitation 
services. 

Potentially a 
share of this 
amount, 
indirectly 

Where 
farmers are 
paid for 
accepting 
sludge on 
agricultural 
land, some of 
the savings 
are thereby 
transferred to 
the farmers. 

Avoided costs per year by avoidance of incineration 

Citizens/Consumers  

Wastewater operators 

Administrations 

Farmers 

Quantitative  

Comment 

Quantitative  

Comment 

Potentially a 
share of this 
amount, 
indirectly 

Depending on 
the financing 
structure of 
water and 
sanitation 
services. 

Recurrent 

Indirect financial 
benefits  
(cost-differential 
compared to other 
sludge management 
routes) 

EUR 41 – 488 
mio/yr 
[EUR 391-488 
mio/yr in 
comparison with 
mono-incineration 
more specifically] 
(or a share of this, 
see comment) 

Savings accrue 
for wastewater 
operators and 
indirectly with 
municipalities or 
customers, 
depending on the 
structure of water 
and sanitation 
services. 

109 

Quantitativ
e 

Potentially 
a share of 
this 
amount, 
indirectly 

Comment   Quantitative 

Comment 

Potentially a 
share of this 
amount, 
indirectly 

Depending 
on the 
financing 
structure of 
water and 
sanitation 
services. 

Where 
farmers are 
paid for 
accepting 
sludge on  
land, some 
of the 
savings are 
thereby 
transferred to 

 
 
 
 
Savings on fertilisers 

Citizens/Consumers  

Wastewater operators 

Administrations 

Farmers 

Quantitative  

Comment 

Quantitative   Comment 

Quantitative 

Comment   Quantitative 

Comment 

the farmers. 

Potentially up 
to EUR 
96/tDS for 
Nitrogen and 
EUR 44/tDS 
for 
Phosphorus 

Benefit 
depends on 
whether the 
farmer 
would have 
applied 
fertilisers in 
the absence 
of sludge. 

Direct benefits   Recurrent 

Avoided resource depletion in relation to fertiliser use 

Citizens/Consumers  

Wastewater operators 

Administrations 

Farmers 

Indirect benefit 

Recurrent 

Quantitative  

Comment 

Not 
quantified 

Benefit depends on 
whether the farmer 
would have applied 
fertilisers in the 
absence of sludge. 

Avoided pressure on landfills and potential reduction in landfill costs 

Citizens/Consumers  

Wastewater operators  Administrations 

Farmers 

Benefit 
(Direct and Indirect) 

Recurrent 

Quantitative  

Comment 

Not 
quantified 

Benefit depends on 
alternative use of sludge 
allowed and selected by 
operators, compared to 
other options like 

110 

 
 
 
 
 
 
 
 
                        
 
 
 
 
 
 
 
 
 
 
 
 
                        
 
 
 
 
 
 
 
 
 
 
 
 
incineration.  

Payment to farmers for taking on sludge application onto agricultural land 

Citizens/Consumers  

Wastewater operators 

Administrations 

Farmers 

Quantitative   Comment 

Quantitative  

Comment 

Quant. 

Cmt  

Quantitative 

Comment 

€100/tDS in Lithuania  
and €100-560/tDS in 
Germany, according to 
two stakeholders, 
respectively. 

Or no cost:  
reports from Bulgaria 
and the UK  suggest 
that farmers do not 
receive payments for 
sludge to be used on 
land 

Farmers can be 
paid to accept the 
application of 
sewage sludge on 
their land. The 
evaluation could 
not assess the 
extent of this 
practice across 
the EU. These 
figures are 
provided based on 
individual 
examples.  

EUR100/tDS in 
Lithuania  and 
EUR 100-
560/tDS in 
Germany, 
according to two 
stakeholder,respe
ctively. 
Or no revenue: 
e.g. reports from 
Bulgaria and the 
UK  suggest that 
farmers do not 
receive payments 
for sludge to be 
used on land 

Farmers can 
be paid to 
accept the 
application 
of sewage 
sludge on 
their land. 
The extent of 
this practice 
across MS is 
not known.. 
These 
figures are 
provided 
based on 
individual 
examples. 

Citizens/Consumers  

Wastewater operators 

Administrations 

Farmers 

Reporting 

Quantitative 

Comment  

€77,000-80,000 
per year per 
Member Stae 

Between 3 person 
days / year to two 
full time 
equivalent staff at 
MS level, 20-40 
days for the  EC, 
reporting on other 
Directives in 

111 

Direct benefit 
(for farmers) 
Direct costs (for 
sludge handlers) 

Recurrent 

Direct Cost 

Recurrent 

 
                        
 
 
 
 
 
                        
 
 
 
 
 
 
 
 
 
 
 
 
Reduced emissions to air, compared to incineration 

Citizens/Consumers  

Wastewater operators 

Administrations 

Farmers 

parallel 

Indirect benefit  Recurrent 

Quantitative  

Comment 

Not quantified 

Incineration is 
associated with 
SO2 and NOx 
emissions which 
are ten times 
higher than land 
spreading options 

Increased GHG emissions due to potential excess applications (compared to plant needs) 

Citizens/Consumers  

Wastewater operators 

Administrations 

Farmers 

Quantitative  

Comment 

Quantitative  

Comment 

Indirect cost  Recurrent  

Not quantified 

Other chemicals and antibiotic resistance 

Citizens/Consumers  

Wastewater operators 

Administrations 

Farmers 

Indirect cost  Recurrent  Not quantified 

Quantitative  

Comment 

Odour nuisance 

Citizens/Consumers  

Wastewater operators 

Administrations 

Farmers 

Indirect cost 

Recurrent 

Qualitative  

Comment 

Not 
quantified 

Can affect 
quality of life, 
impact on 

112 

 
 
                        
 
 
 
 
 
 
 
 
 
 
 
 
                        
 
 
 
 
 
 
 
 
 
 
 
                        
 
 
 
 
 
 
 
 
 
 
 
 
 
                        
 
 
 
 
 
 
 
 
 
 
 
 
tourism 

Report any simplification, burden reduction and cost savings achieved already by the intervention evaluated, including the points of comparison/ where 
available (e.g. REFIT savings predicted in the IA or other sources).  

TABLE 2:  Simplification and burden reduction (savings already achieved)  

No simplification or burden reduction was identified 

PART II: II Potential simplification and burden reduction (savings) 
Identify further potential simplification and savings that could be achieved with a view to make the initiative more effective and efficient without 
prejudice to its policy objectives204. 

Description: Simplification of 
reporting systems with 
UWWTD, EEA and Eurostat 

Recurrent 

Citizens/Consumers/Workers 

Businesses 

Administrations 

[Other…] _ specify 

Quantitative  

Comment 

Quantitative   Comment 

Quantitative  Comment   Quantitati

Comment 

ve 

Not 
quantified 

113 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
204    This assessment is without prejudice to a possible future Impact Assessment. 

114 

 
 
                                                                                                                                                                                                                                                        
 
ANNEX V. STAKEHOLDERS CONSULTATION - SYNOPSIS REPORT  

This  Annex  provides  an  overview  of  the  consultation  activities  carried  out  in  line  with 
the consultation strategy for this evaluation, as well as the responses and results received. 

Consultation strategy 

The Consultation Strategy205 for the evaluation of the Sewage Sludge Directive presented 
the  context  of  the  evaluation,  the  objectives  and  scope  of  the  consultation,  the  relevant 
stakeholder groups, the consultation methods to be used to collect stakeholder input, and 
relevant sources of information.  

The  key  objectives  of  the  consultation  process  were  (i)  to  complement  already  known 
data  and  literature  on  the  implementation  of  SSD  and  (ii)  to  understand  the  extent  at 
which the Directive has been successfully implemented, the extent to which its objectives 
were  met,  the  challenges  it  encountered,  and  whether  there  have  been  trade-offs  in  the 
implementation.  

The  consultation  methods  and  tools  outlined  in  the  Strategy  have  been  followed,  as 
described  in  more  detail  in  the  following  sections.  The  following  table  presents  the 
stakeholder  groups  mapped  against  each  consultation  activity  carried  out  for  this 
evaluation.  

Stakeholder groups consulted by each consultation approach 

Stakeholder type  

Consultation activity 

Roadmap/OPC   Targeted 

Interviews  Workshop 

consultation 
(Survey) 

EU  Member  States 
and 
their  public 
authorities  

Waste expert group 
and UWWTD expert 
group 

Industrial/economic 
actors 

Non-Governmental 
Organisations 

International 
organisations 

Academia 

Citizens 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

205https://ec.europa.eu/environment/pdf/waste/sludge/Stakeholder%20Consultation%20Strategy%20-

%20Evaluation%20of%20SSD.pdf 

115 

 
 
 
 
 
 
 
 
 
 
 
 
                                                 
Methodology and tools used to process data 

Data  gathered  through  different  consultation  tools  required  different  methodological 
approach for their respective analysis. All data gathered as part of questionnaires (i.e., the 
OPC  or  the  targeted  surveys)  were  systematically  cleaned  and  checked  before  their 
analysis.  No  duplicate  responses  were  spotted.  In  addition,  no  significant  update  of 
formatting / data structure was required. Qualitative information was received through a 
number  of  channels:  surveys;  the  open  text  response  to  the  OPC;  and  position  papers 
uploaded as part of the feedback requested for the targeted stakeholder survey, the OPC, 
and  the  Evaluation  Roadmap.  The  analysis  of  the  responses  provided  was  conducted 
according to the evaluation criteria (effectiveness, efficiency, relevance, coherence, and 
EU  added  value).  As  the  answers  cannot  be  considered  as  statistically  representative, 
they have been interpreted with caution for the evaluation of the Directive. 

Evaluation roadmap 

A  Roadmap206  for  the  evaluation  of  the  SSD  was  published  on  16  June  2020  and  was 
open for feedback until the 25th of August 2020. A total of 69 responses were submitted 
through the online portal (and one directly to DG Environment by email). 

Feedback  has  been  received  from  70  respondents,  from  company  business  or 
organisations  (n=26),  business  associations  (n=14)207,  EU  citizens  (n=9),  public 
authorities (n=8), NGOs (n=7), anonymous (n=3) and academic or research institutions 
(n=2)208.  

Several of the comments actually included suggestions for potential changes and future 
revision  (i.e.,  forward-looking),  which  is  not  the  focus  of  the  evaluation.  These 
comments  were  analysed  separately  and  fed  into  the  evaluation  where  appropriate, 
keeping in mind that suggestions for changes mean that one sees failures or shortcomings 
in  the  current  system.  In  particular,  the  feedback  submitted,  and  evidence  attached  in 
position papers were extracted and assigned to each evaluation criteria and contributed to 
the  evidence  base  of  the  analysis  and  the  evaluation  matrices.  Other  forward-looking 
feedback  that  could  not  be  used  for  the  evaluation  will  be  used  in  a  follow  up  to  the 
evaluation. 

Online Public Consultation 

The OPC included questions tailored to examine the effectiveness, efficiency, relevance, 
coherence,  and  EU  added  value  of  the  implementation  of  the  SSD.  It  consisted  of 
introductory questions related to respondent profile, followed by a questionnaire divided 
into five parts. From these six sections, five were addressed to all participants regardless 
of their level of knowledge of the Directive and its implementation, while one was only 
targeted to respondents with specific interest and more in-depth knowledge of the topic 
of sewage sludge. 

206https://ec.europa.eu/info/law/better-regulation/have-your-say/initiatives/12328-Sewage-sludge-use-in-farming-

evaluation_en 

207 Business associations are umbrella organisations 
208  All 

the  contributions  received  are  available  at:  https://ec.europa.eu/info/law/better-regulation/have-your-

say/initiatives/12328-Sewage-sludge-use-in-farming-evaluation/feedback_en?p_id=8009680 

116 

 
 
 
                                                 
The  survey  was  uploaded  in  all  EU  languages  on  the  Have  your  say209  portal  the 
European  Commission  website.  The  consultation  ran  for  16  weeks,  from  20  November 
2020  to  5  March  2021,  longer  than  the  usual  12  weeks  to  accommodate  stakeholder 
needs which have arisen  due to the restrictions resulting from the Covid-19 pandemic. A 
total of 181 responses were submitted, with respondents’ profile synthesised below. 

Feedback received 

After some questions regarding the profile of respondents in section 1, sections 2-4 of the 
questionnaire were addressed to all respondents. They covered their understanding of the 
SSD,  its  costs  and  benefits,  its  added  value  and  its  relevance.  Section  5  targeted 
specialised  respondents  and  included  more  in-depth  questions  on  implementation, 
adequacy in the approach taken, and potential gaps in the coverage of the directive or its 
implementation.  Respondents  could  also  share  additional  publications  or  other 
information in section 6. As most of the questions were not mandatory, the total number 
of responses for each question varies throughout the report.  

Respondents’ profile 

181 responses were submitted. Out of these, 100 respondents indicated their country of 
origin.  Overall,  22  EU  Member  States  were  represented,210  as  well  as  3  non-EU 
countries211.  The  most-represented  country  was  Germany  (n=17;  17%  of  those  who 
reported  their  MS),  followed  by  Italy  and  Sweden  (n=13;  13%  each).  Business 
associations were the most represented category of respondents (n=30; 30% of those who 
indicated  the  category  of  respondent  to  which  they  belong),  followed  by  individual 
company/business  organisations  (n=28;  28%),  meaning  that  58%  of  respondents 
belonged  to  the  private  sector.  All  other  categories  of  stakeholders  were  represented, 
including public authorities (n=11; 11%), EU citizens (n=7; 7%), NGOs (n=5; 5%) and 
academic/research institutions (n=3; 3%). Private sector respondents were predominantly 
located in Germany, Italy, and Sweden. This aligns with replies on the country of origin 
of respondents, as the same three countries are most represented. The top three areas of 
operation of private actors were wastewater treatment plants, sewage sludge processing 
and waste management. Above 70% (n=120 out of 167 responses to this question) of the 
organisations were involved in  or directly  affected by the recovery, treatment or use of 
sludge  and/or  wastewater.  Most  respondents  stated  that  they  have  a  good  or  excellent 
knowledge of the treatment of sewage sludge (n=141; 80% of the 176 respondents to this 
question), of the implementation of the SSD (n=123; 69% of the 179 respondents to this 
question), and of its legal text (n=131; 74% of the 179 respondents to this question). 

Effectiveness 

As can be seen in  Figure 1 below, most respondents  generally believed that (i) there is 
room  for  further  use  of  sewage  sludge  generally  speaking,  (ii)  sewage  sludge  is  in 
general  appropriately  treated  before  being  used,  and  (iii)  sewage  sludge  is  used 
effectively in line with the waste hierarchy. On the other hand, stakeholders agree less on 

209 

https://ec.europa.eu/info/law/better-regulation/have-your-say/initiatives/12328-Sewage-sludge-use-in-farming-

evaluation/public-consultation_en 

210  No  respondents  reported  Bulgaria,  Croatia,  Cyprus,  Latvia  or  Slovenia  as  their  country  of  origin  or  the  country 

where their organisation is located 
211 Liechtenstein, Norway and Switzerland 

117 

 
 
                                                 
 
whether  sewage  sludge  is  a  source  of  pollution  as  74  out  of  175  respondents  (42%) 
disagreed  or  strongly  disagreed  with  this  statement  and  69  (39%)  agreed  or  strongly 
agreed.  Comparing  the  responses  across  stakeholder  types212,  private  actors  were  more 
inclined to disagree that sewage sludge is a source of pollution, whereas the opposite was 
true  for  academic/research  institutions  and  NGOs.  EU  citizens  as  well  as  public 
authorities were split. 

Figure 1 
[.] is .? 

In your country of residence, to what extent do you think that sewage sludge 

Figure 2 
[…] is a source of pollution? 

In your country of residence, to what extent do you think that sewage sludge 

Figure  2  highlights  those  responses  are  quite  divided  within  MS,  perhaps  with  the 
exception of France and Italy, where comparatively less respondents considered sewage 
sludge  to  be  a  source  of  pollution.  Hence,  responses  to  this  sub-question  vary  more 
across stakeholder type than across MS. 

In terms of experiencing negative impacts from the use of sewage sludge in agriculture, 
over half of the respondents to this question indicated that they have not  experienced a 
situation in which the use of sewage sludge in agriculture has resulted in negative effects 
on the environment or on human beings (n=93 out of 172; 54%), whereas almost a third 
had experienced such a situation (n=54; 31%). Personal experiences of negative effects 

212 When the type was specified by the respondent 

118 

 
 
 
 
                                                 
were  also  shared  by  respondents,  and  related  to  olfactive  nuisance,  effects  on  human 
health,  and  environmental  effects  (including  water  pollution,  soil  pollution,  and  the 
presence of certain pollutants).  

As can be seen in Figure, over half of the respondents (n=90 out of 171 respondents to 
this question; 53%) noted that the use of sewage sludge in agriculture had positive effects 
for  vegetation  (trees,  plants)  and  for  soils.  Academic/research  institutions,  business 
associations,  companies/business  organisations,  environmental  organisations  and  public 
authorities  voiced  more  positive  than  negative  opinions,  whereas  NGOs  voiced  more 
negative  opinions  than  positive  ones,  and  with  EU  citizens  divided.  Responses  on 
vegetation (trees, plants) and on soils were somewhat homogeneous across the six most-
represented  MS,  213  except  in  France  where  no  negative  response  was  recorded.  With 
regards  to  effects  on  surface  and  groundwater,  only  either  neutral  of  negative  effects 
were  reported  by  respondents  from  Sweden,  Germany  and  Belgium,  whereas  positive 
effects were reported by a limited number of respondents from Spain (n=2), Italy (n=3) 
and France (n=1). 

Figure 3 
In  your  country  of  residence,  and  since  the  entry  into  force  of  the  Sewage 
Sludge  Directive  (SSD),  to  what  extent  do  you  think  that  the  use  of  sewage  sludge  in 
effect  on  …
a  positive  or 
agriculture  has  had 

a  negative 

either 

Efficiency 

In  terms  of  the  costs  and  benefits  of  the  Directive,  there  was  a  tendency  to  value  the 
social and environmental benefits that the SSD bring more than its costs, considering the 
cost-benefit  balance  at  both  national  and  EU  levels.  This  statement  is  valid  for  all 
stakeholder  types,  with  the  following  two  exceptions:  NGOs  viewed  the  costs  as 
outweighing  the  benefits  under  all  sub-questions,  214  and  EU  citizens  were  split  on 
whether the costs outweigh the environmental benefits  in  their country of residence.  In 
addition, the results highlight that respondents were more aware of the costs and benefits 
of the SSD in  their respective countries of residence than at  EU level,  irrespectively of 
their stakeholder type. 

213 Belgium, France, Germany, Italy, Spain, Sweden. 
214 In total, 3 NGOs answered to this question. Due to this low representation, results should not be generalised. 

119 

 
 
 
                                                 
Considering the benefits of the SSD in terms of ensuring the safe use of sewage sludge 
in agriculture and the costs of its implementation […] in your country of residence and at 
EU level, would you say…? 

Added value of the SSD 

Responses related to the added value of the SSD highlight a consensus that the Directive 
led to improvements in quality of sewage sludge used in agriculture and that there is still 
a need for the EU to regulate sewage sludge use.  

According  to  most  respondents  (n=94  out  of  173  respondents  to  this  question;  54%), 
improvements in quality of sewage sludge used in agriculture can be attributed at least to 
some  extent  to  the  SSD.  Respondents  who  identified  as  farmers  were  split  on  this 
question,  with  9  answering  positively  on  the  role  of  the  SSD,  and  10  answering 
negatively. In open replies, respondents explained that although the SSD had contributed 
positively  to  improvements  in  the  quality  of  sewage  sludge  used  in  agriculture,  many 
national regulations are stricter. Finally, there was an overwhelming consensus that there 
is still a need for the EU to regulate the use of sludge in the agriculture sector (n=140; 
80%),  with  replies  discussing  how  the  SSD  could  be  improved  in  the  open  field 
responses. 

Relevance 

Overall,  the  relevance  of  the  SSD  to  the  needs  of  various  sectors  was  deemed  to  vary. 
Responses on the extent to which the SSD is still relevant to address current needs of a 
list of sectors at local, national, and EU levels were broadly divided. Comparing answers 
to all sub-questions, respondents judged the SSD to be most relevant to the needs of the 
wastewater  treatment  sector  and  of  circular  economy.  On  the  other  hand,  respondents 
judged  the  SSD  to  be  currently  least  relevant  about  its  capacity  to  protect  biodiversity 
and health. Results for the agriculture sector, which is of primary relevance to the SSD, 
suggest the existence of divided opinions on the relevance of the SSD for agriculture at 
the local level, with 47% (n=82 out of 173 respondents to this question) of respondents 
judging it little or not relevant at all, and another 47% (n=82) of respondents conversely 
judging it largely or fully relevant. 

Coherence 

Respondents’ awareness of the coherence of the SSD with other EU policies was rather 
low, with ‘I do not know’ answers averaging 38% across all the policies listed under the 
coherence question (nonetheless, specific mentions of coherence with other EU policies 
were made in several open questions later on). According to the respondents, the Urban 
Wastewater Treatment Directive is the most coherent EU policy with the SSD (“Agree” 
or  “Strongly  agree”  n=86  out  of  173  respondents  to  this  question:  50%).  Respondents 

120 

 
 
 
identifying as from the wastewater treatment sector agreed more than they disagreed.  215 
It is followed by the Circular Economy Action Plan and the Nitrates Directive (“Agree” 
or “Strongly agree” n=61 for both out of 171 and 170 respondents to this question: 36%). 
Respondents  identifying  as  farmers  agreed  more  than  they  disagreed  that  the  SSD  was 
coherent with the Nitrates Directive.  216 The lowest level of coherence was noted for the 
the  European  Green  Deal  (n=56  out  of  171  respondents  to  this  question;  33%)  and  the 
Fertilising Products Regulation: of 172 respondents, 27% agreed that the SSD is coherent 
with  the  Fertilising  Products  Regulation.  37%  disagreed  and  13%  were  neutral.  The 
remaining respondents did not know/no opinion. Additional comments indicated that the 
Fertilising  Product  Regulation  does  not  cover  many  sludge-derived  materials,  thus 
sewage  sludge  is  not  fully  in  scope.  Aqua  Publica  Europea  (European  Association  of 
Public Water Operators) also sees this as hampering trust in these materials217. 

Expert specific questions 

The  expert  questions  were  responded  to  by  160  respondents,  who  self-identified  as 
experts  in  the  area.  Respondents  indicated  that  the  perception  of  sewage  sludge  use  in 
agriculture  by  stakeholders  and  the  general  public  was  the  factor  most  hindering  the 
achievement  of  the  SSD’s  objectives  (n=48  out  of  152  respondents  to  this  question: 
32%). However, once again views diverged as 31% (n=47) believed that perceptions of 
sludge  use  have  facilitated  or  greatly  facilitated  the  achievements  of  the  SSD’s 
objectives.  The  three  factors  deemed  to  have  greatly  facilitated  the  most  these 
achievements  were  the  “Technologies  and  infrastructures  in  place  at  wastewater 
treatment  plants”  (n=34  out  of  150  respondents  to  the  question;  23%),  “Requirements 
relating to concentrations of heavy metals in sludge” (n=35 out of 152 respondents to the 
question; 23%) and the “maximum annual quantities of such heavy metals which may be 
introduced  into  soil  intended  for  agriculture”  (n=34  out  of  151  respondents  to  the 
question; 23%). 

Expert respondents were also divided on the extent to which the changes in amounts of 
sewage sludge use in agriculture and the safety of its use in their country of residence can 
be attributed to the SSD and its transposition into (sub-)national law. Nevertheless, 79% 
(n=122 out of 155 respondents to this question) agreed that it had at least played a role to 
some  extent.  Over  half  of  respondents  (n=82  out  of  156  respondents  to  this  question; 
53%) agreed that other (sub-)national laws were to a large extent or fully responsible for 
the changes observed in their country of residence, as a result of more stringent measures 
put in place by some MS.  

Respondents were divided on whether the difference in approaches taken by EU MS to 
implement the SSD has had any negative impacts, with 44% of respondents (n=70 out of 
158 respondents to this question) answering “yes”, and 35% (n=55) answering “no”. The 
most-mentioned negative impact was the creation of an uneven level-playing field. When 
asked  about  whether  they  knew  of  any  unintended  effects  (positive  or  negative)  which 
the SSD has had, the most mentioned unintended negative effect was that the SSD led to 
an  increase  in  awareness  about  sewage  sludge  and  its  use  in  agriculture,  which 

215 30 out of 59 (50%) agreed or strongly agreed, while 11 (18%) disagreed or strongly disagreed. 
216 9 out of 20 (45%) agreed or strongly agreed, while 4 out of 20 (20%) disagreed or strongly disagreed. 
217 Aqua Publica Europea, 2019 

121 

 
 
                                                 
paradoxically  led  to  more  fear  and/or  misinformation  about  safety,  as  people  were 
previously  unaware  that  sludge  was  used.  Linked  to  this  first  point,  other  respondents 
explained  that  the  SSD  has  even  led  to  the  prohibition  of  sewage  sludge  use  by 
buyers/processors  of  agricultural  products  or  public  authorities.  The  most  mentioned 
unintended  positive  effect  of  the  SSD  was  that  it  led  to  an  increased  interest  in  –  and 
knowledge about – sewage sludge, including looking at new methods to reuse sludge.  

For each pollutant regulated by the SSD,  over half of the respondents  fully  agreed that 
there is still a need to regulate at EU level (varying between n=80; 56% for Copper and 
Zinc  to  n=105;  72%  for  Mercury),  218  highlighting  a  consensus  on  the  relevance  of 
continued EU regulation. Opinions were more divided on the appropriateness of the limit 
values.  Although  for  all  pollutants,  more  respondents  believed  that  the  threshold  was 
fully  appropriate  than  not  appropriate  at  all  (across  the  six  pollutants,  the  average 
proportion  of  ‘not  appropriate  at  all’  was  20%,  and  the  average  proportion  of  ‘fully 
appropriate’ was 37%), we can deduce a general trend whereby respondents believe that 
there  is  room  for  setting  more  stringent  thresholds.  Moreover,  a  majority  of  expert 
respondents  thought  that  some  pollutants  are  missing  from  the  SSD  (n=116  out  of  154 
respondents  to  this  question;  75%),  with  a  variety  of  pharmaceuticals,  pesticides  and 
herbicides, plastics, chemicals  found in  personal care  and household  cleaning products, 
and  substances  used  during  wastewater  treatment  (including  flocculants)  listed  in  the 
open replies. Linked to this, expert respondents believed that the SSD has not been – up 
until now – very successfully in dealing with new and emerging risks. The lowest rated 
elements  were  its  capacity  to  deal  with  pollutants  of  emerging  concern  and  with 
substances other than the heavy metals already regulated. 

Anaerobic digestion was the method considered the most suitable for sewage sludge pre-
treatment  /  processing  by  respondents,  with  38%  (n=58  out  of  154  respondents  to  this 
question)  judging  the  method  as  fully  suitable.  The  second  favoured  method  was 
composting,  with  25%  (n=38  out  of  155  respondents  to  this  question)  assessing  this 
method  as  fully  suitable.  219  Land  spreading  for  agriculture  was  considered  the  most 
suitable method to dispose of sewage sludge, with 30% (n=46 out of 153 respondents to 
this question) of respondents finding it fully suitable. 220 Finally, the most favoured option 
for nutrient recovery was the precipitation of phosphoric minerals from sludge, although 
the combined answers “fully” and “to  a large extent” failed to  reach 50% (n=76 out  of 
152 respondents to this question: 46%). 221 

Half of the respondents (n=26 out of 52 respondents to this question; 50%) answered to 
the open question on the added value of EU intervention in  a forward-looking manner, 
pointing to the view shared by many respondents throughout previous questions that the 
SSD needs to be updated 

218 Total answers received: n=143 for Copper, n=144 for Zinc, n=145 for Mercury 
219  The  methods presented in  this  question  were:  drying,  lime  treatment,  heating  for  pasteurization, composting,  and 

anaerobic digestion. Respondents could also specify other methods. 

220  The  methods  presented  in  this question  were:  gasification,  incineration,  landfilling,  land  spreading  for  landscape, 
land spreading for forestry/re-forestation, and land spreading for agriculture. Respondents could also specify other 
methods. 

221  The  methods  presented  in  this  question  were:  precipitation  of  phosphoric  minerals  from  sludge,  recovery  of 

nutrients from incineration ashes, and pyrolysis. Respondents could also specify other methods. 

122 

 
 
 
                                                 
Final questions 

The  answers  provided  in  this  open  field  overwhelmingly  focused  on  forward-looking 
recommendations  or  remarks  (n=57;  74%).  A  quarter  of  respondents  to  this  question 
(n=19;  25%)  discussed  pollutants  in  sewage  sludge.  Respondents  also  assessed  and 
compared different sewage sludge recycling use, recovery use and disposal routes (n=21; 
27%), with a tendency to agree that land application of sewage sludge is an appropriate 
and  cost-effective  method  for  nutrient  recovery,  provided  that  sewage  sludge  has  been 
treated  prior  application.  However,  the  reliance  on  more  costly  and  energy-intensive 
methods  is  needed  when  sludge  is  too  contaminated  (incineration,  pyrolysis),  and  can 
lead to energy recovery or phosphorous recovery. Finally, a large number of respondents 
made other recommendations regarding how the SSD could be improved, with the most 
often mentioned themes being the need to explicitly focus on nutrient recovery (N and P) 
(n=13; 17%), the need for an updated approach to control, with some discussing Quality 
Assurance systems (n=6; 8%), and the need to improve coherence with  ambition of the 
EU policies (n=22; 28%). 

Targeted consultations 

Targeted  stakeholder  consultations  were  conducted  via  surveys,  interviews,  and  a 
workshop. The aim was to gather detailed feedback and data from stakeholders directly 
involved  in  the  implementation  of  the  SSD,  or  from  stakeholders  with  a  substantial 
expertise on the topic. The survey was composed of one section addressed to all targeted 
stakeholders and five additional sections each addressed to a specific stakeholder group. 
222 

Surveys of Member States’ authorities  

The  survey  was  disseminated  to  stakeholders  on  3rd  January  2021,  apart  from  the 
Member States authorities, and remained open until 2nd April 2021. The survey directed 
specifically  to  Member  States’  competent  authorities  was  distributed  on  23rd  March 
2021  and  remained  open  until  25th  April  2021.  An  additional  targeted  consultation  of 
water regulators was undertaken between the 3rd of June and 15th of July to gather data 
on  costs  and  benefits  of  the  SSD.  There  were  63  responses  to  the  targeted  survey, 
including  by  company  /  business  organisations  (n=18;  29%),  national  government  / 
administration  (n=13;  21%),  business  associations  (n=12;  19%),  academic  or  research 
institutions  (n=5;  8%),  national  authorities  (n=5;  8%),  and  NGOs  (n=3;  5%).  For  the 
additional  consultation  with  water  regulators,  the  consultation  consisted  of  a  written 
questionnaire with an offer to discuss the responses through an interview. However, no 
response to the questionnaire was received to date. Although cost and benefit estimates 
from  water  regulators would  have added a higher degree of confidence to  the  analysis, 
they are not considered crucial for discerning conclusions. 

222 Namely: 1. Stakeholders from the wastewater treatment and sludge processing and treatment industry and sewage 
sludge producers and intermediate users. 2. Agricultural associations, consumer organisations, and sewage sludge 
end  users.  3.  Academics  and  health  and  environmental  experts.  4.  NGOs  and  international  organisations.  5. 
Member State competent authorities. 

123 

 
 
 
 
                                                 
Workshop 

In order to allow for expert discussions on key topics and to present preliminary findings, 
a  workshop  was  organised  focusing  on  synergies  between  wastewater  and  sludge  and 
circular economy. The workshop was attended by 376 participants and was split in two 
half-days: 20th of April in the afternoon and 21st of April in the morning. Following the 
workshop,  participants  had  the  opportunity  to  send  further  comments.  The  workshop 
summary report is available on circabc223.  

Interviews 

Individual interviews were held with five stakeholders, including a business association, 
a representative of a pilot project and a wastewater operator. The aim of the interviews 
was to address very specific data gaps remaining after the literature review and analysis 
of the other consultation activities (e.g., costs and benefits). 

Feedback received  

Feedback from targeted surveys 

The written surveys received 63 responses, of which the largest number of replies came 
from  Belgium (n=10), followed by Finland (n=9) and France (n=9). The remaining top 
10 participants (Germany, Spain, Sweden, Italy, Austria, Lithuania, and the Netherlands) 
had  a  relatively  similar,  small  number  of  participants  (between  2  and  6).  Remaining 
countries had no more than one respondent, and there were no respondents from Cyprus, 
Hungary, Ireland, Malta, and Romania. 

Respondents’ profile 

Most  of  the  respondents  came  from  a  company/business  organisation  (n=18),  national 
government/administration  (n=13)  or  a  business  association  (n=12).  There  was  equal 
share  of  representatives  from  the  academic/research  institution/health  and  environment 
experts and national authority sectors (n=5), and similarly proportional representation in 
the  NGO  and  ‘Other’  sectors  (n=3)  and  equal  representation  in  the  environmental 
organisation 
one 
company/business organisation respondents were directly involved in the wastewater or 
sludge  management  activities,  with  one  involved  in  fertiliser  products.  While  all 
stakeholder  groups  were  represented,  a  majority  came  from  the  private  sector 
(company/business  organisations  and  associations)  or  national  public  bodies  (national 
government/administrations and national authorities). 

government/administration 

(n=2).  All 

regional 

and 

but 

General part of the questionnaire 

Respondents  were  in  strong  agreement  that  the  SSD  had  led  to  a  generally  sustainable 
framework for the use of sewage sludge in agriculture (73% agree or strongly agree), had 
led to increased safe use of sewage sludge in agriculture (64% agree or strongly agree), 
and led to minimisation of pollution and health risks from sewage sludge (65% agree or 
strongly  agree)  (see  Figure  0  2).  They  were  less  equivocal  that  the  SSD  had  led  to 
phosphorus  and  nutrient  recycling  and  carbon  sequestration,  or  to  a  measurable 
improvement in the quality of agricultural soils. 

223 Circabc (europa.eu) 

124 

 
 
                                                 
Some other key findings from the responses to the questions of the general questionnaire 
include: 

-  While 14 of 39 respondents (36%) did not think the SSD has led to any other changes 
than those described above, 5 stakeholders identified the SSD as providing a source 
of organic matter for soils as a key additional significant change  

-  The  most  supported  positive  factor  contributing  to  achievement  of  the  SSD’s 
objectives was stricter limit values of one or more heavy metals concentrations than 
would have been without the SSD (n=39; 65%) 

-  The  most  supported  negative  factor  seen  to  hamper  the  achievement  of  the  SSD’s 
objectives was the negative perception of sewage sludge by the food industry due to 
potentially contaminated soils or agricultural products (n=19; 33% strongly agree) 
-  Enforcement of the SSD was considered fully effective or largely effective by 42% of 

respondents (n=25) 

-  A  majority  of  respondents  (55%,  n=22)  indicated  that  no  unnecessary  operational 

burdens or complexities have stemmed from the SSD implementation. 

-  Most  stakeholders  did  not  consider  the  link  between  the  Fertilising  Products 
Regulation and the SSD was made explicit enough (62%, n=38 thought ‘not at all’ or 
‘to some extent’). 

-  Stakeholders thought the strongest coherence of the SSD was with the New Circular 
Economy  Action  Plan,  the  Waste  Framework  Directive,  and  the  Water  Framework 
Directive 

-  Stakeholders generally thought the SSD was coherent with national legislation (65%, 

n=40 reported ‘fully’ or ‘to a large extent’) 

-  67%  of  respondents  (n=41)  reported  that  there  are  important  pollutants  found  in 
sewage that the SSD does not currently take into account (examples include organic 
pollutants 
disruptors,  microplastics, 
(pharmaceutical 
polymers/polyelectrolytes, and pathogens) 

endocrine 

goods), 

-  34%  of  respondents  reported  that  there  are  pollutants  that  no  longer  need  to  be 

regulated by the SSD. 

-  85% of respondents expected anaerobic digestion to be the treatment technique most 
likely to grow over the next decade, and 64% expected incineration to increase over 
the same period. 

125 

 
 
Responses to: From your experience, to what extent do you agree that the SSD has led 
to the following changes or results in your country (or on average in the EU if you 
represent an EU-level organisation)? 

Specific stakeholder surveys 

Out of the 63 respondents to the targeted consultation surveys, the following number of 
respondents addressed the subsequent questions targeting specific stakeholder groups: 

-  28 respondents addressed questions targeting sludge producers 
-  3  respondents  addressed  questions  targeting  sludge  users,  of  which  2  reported  they 

operated at national level and one at EU level 

-  5  respondents  addressed  questions  targeting  academics,  2  of  which  were  from 

Finland, and one each from Germany, Sweden, and Italy 

-  4 respondents addressed questions targeted at NGOs and international organisations 
-  20 respondents addressed questions specifically targeting Member State authorities. 

Key points made by different stakeholder groups can be summarised as follows: 

  Most sludge producers indicated that the demand for sewage sludge in agriculture has 
remained more or less the same (n=12, 43% of respondents) or has decreased (n=11, 
39%  of  respondents)  over  the  past  five  years  in  their  country  or  in  the  EU27  on 
average. 

  Most  sludge  producers  maintained  that  the  SSD  is  “not  at  all”  (n=12,  45%  of 
respondents)  fit  for  purpose  with  respect  to  technical  and  scientific  progress,  while 
nine (or 33% of replies) and four respondents (or 15% of replies) found the SSD to be 
“to  some  extent”  and  “to  a  large  extent”  fit  for  purpose,  respectively.  None  of  the 
sludge producers who participated in the survey believed that the SSD is fully fit for 
purpose. 

  Most sludge producers believed that in the future there will be an increase in treatment 
costs  of  sewage  sludge  (93%  of  28  respondents),  in  nutrient  recovery  from  sewage 
sludge (93% of 28 respondents), in energy produced from sewage sludge (82% of 28 
respondents), and in production of sewage sludge (75% of 28 respondents). Three out 
of  three  sludge  users  who  participated  in  the  survey  agreed  that  sewage  sludge 
production will increase while demand will decrease. 

  Two out of three sludge user respondents mentioned that the risks associated with the 
spreading  of  sewage  sludge  on  agricultural  land  are  managed  properly  in  their 

126 

 
 
 
respective  Member  States,  while  one  was  of  the  opposite  opinion  due  to  the  low 
threshold values set by the SSD. 

  Two  out  of  three  sludge  user  respondents  agreed  that  the  use  of  sewage  sludge  in 
agriculture  has  reduced  the  cost  of  fertilisation  for  farmers,  and  one  disagreed 
pointing out that the long-term costs overweigh the short-term benefits. 

  Four  out  of  five  academics  and  all  four  NGOs  that  replied  the  respective 
questionnaires  agreed  that  at  least  to  some  extent,  the  SSD  provisions  have  been 
effective in ensuring that sewage sludge is used safely on agricultural soil. Although 
most respondents (n=4 academics and n=4 NGOs) believed that the SSD, at least to 
some extent, still covers the most important pollutants relevant for protection of the 
environment  and  human  health,  three  academic  respondents  and  two  NGO 
respondents mentioned that limit values of pollutants set by the SSD are no longer 
appropriate  and  should  be  more  stringent,  which  was  also  raised  by  many 
respondents in the OPC. 

  Most  of  the  Member  State  authority  representatives  that  answered  the  dedicated 
questionnaire believed that the SSD provisions are only “to some extent” (n=7, 37% 
of  respondents)  burdensome  for  national/regional/  local  administrations/authorities 
or “not at all” burdensome (n=5, 26% of respondents). 

  Most Member State authority representatives also stated that limit values set by the 
SSD  are  not  stringent  enough  (n=13  or  65%  of  respondents),  while  6  (or  30%  of 
respondents) believed that they are adequate. 

Position papers 

Stakeholders were given the opportunity to submit with additional feedback. In total, 26 
position  papers  were  received,  where  25  of  them  (at  least  to  some  extent)  provided 
relevant  input.  Regarding  the  inputs  directly  relevant  for  the  evaluation,  a  number  of 
issues  were  raised,  mainly  in  relation  to  substances  of  concern  (e.g.,  micropollutants, 
microplastics,  pharmaceuticals,  POPs,  etc.).  More  specific  points  were  also  raised  by 
stakeholders concerning the absence of limits on dangerous substances in sewage sludge 
and  the  need  to  consider  the  introduction  of  the  ‘extended  producer  responsibility’ 
(EPR).  Three  other  points  on  different  aspects  were  raised  in  position  papers:  (i)  the 
revision of the SSD should  focus on  encouragement of recovery of  raw materials  from 
sludge  (n=3);  (ii)  consistency  with  other  relevant  EU  instruments  should  be  ensured 
during  the  revision  of  the  SSD  (n=2);  and  (iii)  the  responsibility  to  regulate  the  topic 
should be left in the hands of Member States Competent Authorities (n=1). 

Expert interviews 

Additional  interviews  with  experts  were  organised  to  fill  very  specific  gaps  in  the 
information  including  on  costs  and  benefits,  possibility  to  improve  quality  of  sludge  at 
source  and  factors  affecting  trust  from  the  public.  Organisations  representing  farmers 
were also contacted and invited to participate. A total of 5 interviews were held and more 
than 20 stakeholders were reached out for interviews.  

The information  received from  the targeted  consultation did  not  include  cost  data  from 
Member  States  that  have  joined  the  EU  after  2003.  The  study  team  reached  out  to  the 
European Water Regulators (WAREG), private sector operators in Bucharest and Sofia. 
The  interview  with  WAREG  indicated  the  priorities  of  WAREG  and  the  types  of  cost 
categories  that  have  been  published.  A  questionnaire  was  circulated  with  WAREG 

127 

 
 
members  and  presented  at  the  WAREG  board.  To  date,  no  cost  information  other  than 
published data on depreciation timeframes was received by the study team from WAREG 
members.  A  detailed  interview  was  conducted  with  a  representative  of  the  operator  for 
Bulgaria who provided detailed cost and operating context information as well as follow 
up documentation.  

A detailed interview was conducted with a representative of a pilot project in Lithuania 
aiming at using sewage sludge digestate as fertiliser for forestry plantation. The interview 
identified some information on costs involved in the pilot project. 

Finally,  an  interview  was  held  with  a  representative  of  the  European  Sustainable 
Phosphorus Platform. 

Workshop 

The first half of the workshop (20th of April) focused on current challenges encountered 
in  terms  of  wastewater  treatment  and  sewage  sludge  management.  The  discussion 
focused  around  how  the  ‘circularity’  of  sludge  management  can  be  improved  while 
ensuring  a  safe  use  of  sludge  notably  in  agriculture.  Three  thematic  sessions  were 
planned,  addressing  the  subjects  of  1-micropollutants,  2-  safe  production  and  use  of 
sludge and 3- methods for the recovery of nutrients and raw material from sludge. There 
were  376  participants  registered,  representing  27  countries  from  the  EU  and  3  non-EU 
countries.  

Key  points  of  discussion  revolved  around  the  persistence  of  contaminants  and  their 
accumulation.  Participants  were  asked  using  Sli.do  which  micropollutants  should  be 
made  mandatory  to  track  in  wastewater  and/or  sewage  sludge  by  EU  policy  and  could 
give any answer they wished. A total of 99 participants provided an answer, and the most 
cited micropollutants were pharmaceuticals, microplastics, heavy metals, PFAS/PFOS.  

There  were  discussions  on  sludge  regulation,  how  to  determine  that  sludge  is  safe  and 
quality control. Stakeholders were particularly interested in how sludge was considered 
‘safe’ and what happens when it was not up to standard. Generally, the approach of using 
sludge for land reclamation instead of agriculture when it fails compliance was regarded 
as an acceptable approach. During the final session of the day, alternative uses of sludge 
were  discussed  such  as  incineration  and  land  restoration.  Particularly  incineration 
discussions  showed  a  divide  between  participants  who  were  strongly  for  or  against 
incineration as a common practice for sludge use. 

The second half of the workshops (21st of April) focused on energy efficiency and GHG 
emissions  from  wastewater  collection  and  treatment,  followed  by  a  series  of  breakout 
sessions. Two of the breakout sessions were particularly relevant for the SSD: addressing 
micropollutants  in  sludge  and  impact  on  soil  where  it  is  applied,  and  recovery  of  raw 
materials from wastewater sewage sludge. Regarding micropollutants the discussion was 
focused  around  PFAS  and  their  long-term  accumulation  rates,  which  stakeholders 
generally noted  as a  concern for sewage sludge  application. The lack of  a standardized 
methodology for detecting and quantifying micropollutants was also raised as a concern. 
Generally,  stakeholders  felt  that  there  needs  to  be  more  information  available  on 
contaminants in sewage sludge as well as an improvement in treatment technology and 
more  source  control.  Finally,  there  was  much  discussion  and  support  for  applying  a 
blending  obligation  for  phosphorus  to  drive  a  market  for  phosphorus  from  wastewater, 
and a general demand for the promotion of coherence between resource recovery policies 
at EU level. 

128 

 
 
 
ANNEX VI. OVERVIEW OF THE REQUIREMENTS OF THE SEWAGE SLUDGE DIRECTIVE 

Key features of the SSD 

Art.3 

• Sewage sludge may be used in agriculture provided that it adheres to any conditions that the Member State may deem necessary to protect human or 

environmental health. Sludge may also only be used if it is regulated by the Member State.

Art.5 

• Prohibits the use of sludge where the concentration of one or more heavy metal in the soil exceeds limit values set down in Annex I A.
• Member States must either lay down maximum quantities of sludge applied to soil or will ensure that the limit values for the quantities of heavy metals added to 

soils, as described in Annex I C, are adhered to.

Art. 6

• Sludge must be treated before it is used in agriculture, although Member States may authorise the use of untreated sludge providing their own conditions are met 

and that the untreated sludge is injected or worked into the soil.

Art. 7

• Sets out a period of time after using sludge before which it is prohibited to allow grassland to be grazed or forage crops to be harvested. 
• Member States may set their own period of time depending on climate and geographical location, but it must never be below three weeks. 
• It is also prohibited to use sludge or supply sludge for use on soil in which fruit and vegetables are growing (with the exception of fruit trees) and on ground intended 

for the cultivation of fruit and vegetables intended to be eaten raw for a period of 10 months before the harvest.

Art. 8

• Requires that sludge is used in such a way that takes into account the nutritional needs of the plants and the quality of the soil. In the case of soils with a pH of below 

6, Member States may be required to reduce the limit values in accordance with Annex I A to account for an increase in mobility and availability to the crops of 
heavy metals.

Art. 9 (and Annex II)

• Sets out limit values, sampling methods and analysis. 

Art. 10

• Details the requirements on records keeping (the quantities of sludge produced and quantities supplied for use in agriculture; composition and properties of sludge 

in relation to Annex II A; the types of treatment carried out; and the names and addresses of recipients of the sludge and the place where the sludge is stored). 

• Records should be available to the competent authorities.
• Information on the treatment and results of analyses should be released upon request to the competent authorities.

Art. 11

• Sets exemptions from Article 6 (b) and Article 10 (1) (b), (c) and (d) and paragraph 2 for, sludge from sewage treatment plants below 5,000 population equivalents as 

these are primarily for the treatment of domestic waste water. 

Art. 12

• Allows Member States to take more stringent measures than those provided by the Directive. 
• When this decision is taken, Member States are required to inform the Commission.

Annexes

• Set out the frequency of sludge and soil analysis as well as the parameters that have to be tested. 
• For the sludge analysis is to be at least every six months unless results do not vary over a full year in which case every 12 months.
• Analyses should cover the following parameters: dry matter, organic matter, pH, nitrogen and phosphorus and cadmium, copper, nickel, lead, zinc, mercury and 

chromium. 

• For soil, the analysis is to be set upon a national frequency. 
• Analyses should cover pH, cadmium, copper, nickel, lead, zinc, mercury and chromium.

Limit values established by the Directive 

The  Directive  imposes  several  requirements  on  the  quality  of  sludge  for  use  in 
agriculture,  the  quality  of  the  soil  on  which  sludge  is  to  be  used  and  limiting  sludge 
application for certain purposes and during certain time periods. The main aim of these 
requirements  is  to  limit  heavy  metal  concentrations  in  soils.  Limit  values  have  been 
defined in the Annexes of the Directive: 

concentrations of heavy metals in soils to which sludge is applied (Annex IA) 

- 
-  heavy metal concentrations in sludge for use in agriculture (Annex IB) 
-  maximum annual quantities of such heavy metals that may be introduced into soil 

through sludge use in agriculture (Annex IC). 

129 

 
 
 
 
[ANNEX I A of the SSD] 

LIMIT VALUES FOR CONCENTRATIONS OF HEAVY METALS IN SOIL 

(mg/kg of dry matter in a representative sample, as defined in Annex II C, of soil with a pH of 6 to 7) 

Parameters 

Cadmium 

Copper (2) 

Nickel (2) 

Lead 

Zinc (2) 

Mercury 

Chromium (3) 

Limit values (1) 

1 to 3 

50 to 140 

30 to 75 

50 to 300 

150 to 300 

1 to 1,5 

— 

(1)   Member States may permit the limit values they fix to be exceeded in the case of the use of sludge on land which at 
the time of notification of this Directive is dedicated to the disposal of sludge but on which commercial food crops are 
being grown exclusively for animal consumption. Member States must inform the Commission of the number and type 
of sites concerned. They must also seek to ensure that there is no resulting hazard to human health or the environment. 
(2)   Member States may permit the limit values they fix to be exceeded in respect of these parameters on soil with a pH 
consistently higher than 7. The maximum authorized concentrations of these heavy metals must in no case exceed those 
values by more than 50 %. Member States must also seek to ensure that there is no resulting hazard to human health or 
the environment and in particular to ground water. 
(3)   It is not possible at this stage to fix limit values for chromium. The Council will fix these limit values later on the 
basis of proposals to be submitted by the Commission, within one year following notification of this Directive. 

ANNEX I B of the Directive 

LIMIT VALUES FOR HEAVY-METAL CONCENTRATIONS IN SLUDGE FOR USE IN AGRICULTURE 

(mg/kg of dry matter) 

Parameters 

Cadmium 

Copper 

Nickel 

Lead 

Zinc 

Mercury 

Chromium (1) 

Limit values 

20 to 40 

1 000 to 1 750 

300 to 400 

750 to 1 200 

2 500 to 4 000 

16 to 25 

— 

(1)   It is not possible at this stage to fix limit values for chromium. The Council will fix these limit values 
later on the basis of proposals to be submitted by the Commission within one year following notification of 
this Directive. 

130 

 
 
 
 
 
 
 
 
LIMIT VALUES FOR AMOUNTS OF HEAVY METALS WHICH MAY BE ADDED ANNUALLY TO AGRICULTURAL LAND, 

ANNEX I C of the SSD 

BASED ON A 10-YEAR AVERAGE 

(kg/ha/yr) 

Parameters 

Cadmium 

Copper 

Nickel 

Lead 

Zinc 

Mercury 

Chromium (2) 

Limit values (1) 

0,15 

12 

3 

15 

30 

0,1 

— 

(1)   Member States may permit these limit values to be exceeded in the case of the use of sludge on land 
which at the time of notification of this Directive is dedicated to the disposal of sludge but on which 
commercial food crops are being grown exclusively for animal consumption. Member States must inform 
the Commission of the number and type of sites concerned. They must also ensure that there is no resulting 
hazard to human health or the environment. 
(2)   It is not possible at this stage to fix limit values for chromium. The Council will fix these limit values 
later on the basis of proposals to be submitted by the Commission within one year following notification of 
this Directive. 

131 

 
 
 
 
 
 
 
ANNEX  VII.  KEY  CONCLUSIONS  RELATED  TO  THE  SSD  FROM  THE  2014  EX-POST 
EVALUATION STUDY 

Evaluation 
criteria 

Conclusions from 2014 study 

Effectiveness  “The Sewage Sludge Directive (SSD) has been effective in achieving its 
initial objectives, by increasing the amount of sludge used in agriculture 
and by contributing to reducing environmental harm by ensuring that 
heavy metals in soil and sludge do not exceed the limits set by the 
Directive.  
All Member States meet the requirements of the Directive in terms of 
heavy metals limit values, although there is considerable variation 
between Member States in the limits applied (both in soil and in sludge).  
There are also large variations in the amount of generated sludge used in 
agriculture in the Member States, ranging from none to well over 50%. “  
The heavy metal limits of the SSD are less stringent than those set in 
many Member States.  

Efficiency 

Coherence 

“The principal benefit of the Sewage sludge Directive is its role in the 
protection human health and the environment against the harmful effects 
of contaminated sludge in agriculture. 
Other benefits include the use of sludge in agriculture as a cheaper 
disposal option compared to landfill and incineration and it is an effective 
replacement for chemical fertilisers, especially phosphorus.  
Estimates from the 2010 study assessing the Sewage Sludge Directive 
indicate that if sewage sludge use in agriculture were no longer an option, 
to be replaced by incineration, the cost would be of the order of EUR 650 
million per year. Despite these clear benefits to using sludge in 
agriculture, rising negative media and public attention in recent years has 
hampered its potential beneficial use on land and in agriculture. The main 
unavoidable costs of the Directive include the treatment and management 
costs of sludge to ensure it meets the Directive’s (or Member States’ 
more stringent) quality standards. “  

“The Directive complements EU waste legislation by encouraging the 
safe use of sludge (moving it up the waste hierarchy), by promoting 
health and environmental protection (by placing limits on heavy metals), 
and by contributing to resource efficiency (through the recovery 
of useful nutrients).” 
“There is strong complementarity and an adequate level of coherence 
with the UWWTD (although the link between the two is not explicit 
within the Directives themselves).” 
The coherence of the SSD with the EU circular economy objectives 
should be assessed.  

Relevance 

“In general, the retention of the SSD as a separate legislative instrument 
is supported by the  majority: only a small number of stakeholders felt 
that sewage sludge management could in principle be integrated into 
other EU legislation (e.g., on soils, biowaste or fertilisers).” 

132 

 
 
Evaluation 
criteria 

Conclusions from 2014 study 

Relevance is limited due to the limited scope of the Directive (which 
addresses only the agricultural use of sludge), and the lack of provisions 
on quality assurance and adequate monitoring.  
Additional contaminants / substances in sludge have been identified that 
could be monitored, however there is not broad support for introducing 
additional limit values in the Directive.  

133 

 
 
 
 
 
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