COMMISSION STAFF WORKING DOCUMENT EXECUTIVE SUMMARY OF THE 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

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   EUROPEAN COMMISSION  Brussels, 22.5.2023  SWD(2023) 158 final  COMMISSION STAFF WORKING DOCUMENT  EXECUTIVE SUMMARY OF THE 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) 157 final}  
 
 
EXECUTIVE SUMMARY 
The  Sewage  Sludge  Directive1  (SSD)  aims  at  encouraging  the  use  of  sewage  sludge  in 
agriculture  while  preventing  negative  health  and  environmental  impacts.  It  sets  quality 
requirements for the sludge and the soil on which it is to be used, by setting upper limits on 
their  content  in  seven  heavy  metals  (cadmium,  copper,  nickel,  lead,  zinc,  mercury, 
chromium).  It  also  requires  sludge  treatment  before  application,  and  consideration  of  the 
nutrient needs of the plants.  

The Directive has never been substantially amended since its  adoption almost 40 years ago. 
Meanwhile, in parallel to progress on the knowledge of sludge properties, treatment and use, 
the  wider  environmental  legislative  and  policy  framework  has  considerably  changed.  Also, 
wide differences in implementation are observed, linked to  the fact that sludge management 
strongly depends on local conditions, or policy choices by Member States (e.g. some of them 
ban  the  use  of  sludge  in  agriculture).  Broadly  speaking,  looking  across  all  heavy  metals 
thresholds  and  parameters  set  by  the  Directive,  over  time  seventeen  of  them  have  adopted 
stricter requirements by setting stricter limits or limits for additional contaminants. 

This evaluation was carried out in view of that, and in line with the European Commission’s 
Better Regulation principles and methodology.  

Effectiveness 

About  40%  of  the  2  to  3  million  tons  of  sludge  yearly  produced  in  the  EU  (17  kg/ha)  are 
applied  on  farmland.  The  other  share  is  incinerated  (27%),  composted  (about  10%),  or 
landfilled  (currently  estimated  at  11%,  and  phasing  out).  Sludge  use  in  agriculture  has 
remained the main route for sludge management in the EU, allowing to curb sewage sludge 
disposal through landfilling, while acting as a fertiliser which also shows to improve further 
soil properties. 

The level of heavy metals in sludge used in agriculture significantly decreased over time, to 
level  below  the  limits  set  by  the  SSD,  very  often  10  times  lower.  While  it  can  be  partly 
attributed to the Directive, it is challenging to distinguish its effect from that of national action 
or of legislation controlling the emission of these pollutants at source.    

The evaluation found very limited information linking soil quality and use of sewage sludge, 
in  particular  on  long-term  effects,  and  research  is  going  on  in  this  regard.  The  current 
reporting system also showed limitations, not only suffering from low compliance by Member 
States,  but  also  not  generating  information  allowing  to  assess  the  impact  of  sludge  use  on 
land,  including  verifying  that  plant  needs  are  taken  into  account  (thereby  preventing 
groundwater  pollution  by  excess  of  nitrates).  The  evaluation  also  identified  room  for  data 
improvement in streamlining reporting under the SSD and the Urban Waste-Water Treatment 
Directive2 (UWWTD) and data flow management at EU level (currently shared between the 
European Environmental Agency and Eurostat). 

Quality standards voluntarily set up between sludge producers and farmers have contributed 
to  achieving  the  objectives  of  the  SSD.  Conversely,  negative  public  perception,  the  lack  of 
EU-wide  end-of-waste  criteria  for  sludge  and  the  use  of  alternative  organic  fertilisers  e.g. 
manure, or, increasingly, biowaste, are identified as hindering factors. 

1 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, OJ L 181, 4.7.1986, p. 6–12 
2 Council Directive 91/271/EEC, OJ L 135, 30.5.1991, p. 40–52 

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The  SSD  also  has  had  unintended  effects,  positive  (sludge  use  in  agriculture  presents  an 
overall negative carbon footprint) or negative (sludge use in agriculture leading to  antibiotic 
resistance  genes  and  microplastics  presence  in  soil,  associated  emissions  of  methane  and  of 
other contaminants not regulated by the Directive).  

Efficiency 

Using sludge in agriculture entails costs, for treatment to make it suitable for use (for safety 
reasons  e.g.  hygienisation,  or  to  ease  transport),  and  for  transport.  These  amount  to  several 
hundreds of euros per ton of dry sludge (tDS). However, it is overall significantly less costly 
than  other  sludge  treatment  options,  especially  (mono-)incineration,  the  main  alternative  to 
the agriculture route. A hypothetical shift of the sludge currently used in agriculture towards 
(mono-)incineration  could  increase  costs  by  €41–488  million/yr,  and,  for  mono-incineration 
only, by €391-488 million/yr. Also, in a theoretical case where sludge would fully substitute a 
mineral  fertiliser,  savings  for  farmers  could  be  some  €96  and  €44/tDS,  for  nitrogen  for 
phosphorus respectively. 

Coherence 
The  SSD  is  in  line  with  the  waste  hierarchy  set  by  the  Waste  Framework  Directive3, 
prioritising  recovery  of  nutrients  over  energy  recovery  and  disposal,  notably  through 
landfilling.  

In  principle,  the  objectives  of  the  Directive  are  also  aligned  with  other  environmental  and 
health  legislation  and  the  linked  policies  outlined  in  the  Zero  Pollution Action  Plan  and  the 
EU Soil Strategy for 2030. However, in practice this coherence would be fully ensured if the 
risks  linked  to  contaminants  present  in  sludge  were  reassessed,  notably  reviewing  the  limit 
values and the set of pollutants which it regulates. 

The revised UWWTD, as proposed by the Commission4 in 2022, could affect the composition 
of sludge, by potentially increasing its content in microplastics, while decreasing the level of 
contaminants  which  the  UWWTD  would  reduce  at  the  source.  It  is  also  bound  to  influence 
sludge treatment practices in view of increasing the energy efficiency of the treatment plants. 

More  broadly,  the  Directive  serves  the  European  Green  Deal,  and  EU  policies  on  climate, 
health, circular economy, security of food supply, and independence in fertilisers, critical raw 
materials  and  energy.  These  policies  influence  sludge  management  policies  differently, 
depending  on  local  conditions  e.g.  the  agronomic  needs  of  soils,  energy  mix  and  available 
infrastructure. It can also favour specific treatments, with varying impacts on carbon footprint. 
Anaerobic  digestion  allows  to  produce  biogas  while  treating  the  sludge,  but  is  not  always 
sufficient  to  remove  certain  pollutants.  Treatment  may  not  always  be  feasible,  where 
infrastructure lacks, or technically, depending on the contaminants to be abated in the sludge. 
In  such  cases,  (mono)incineration  could  be  a  last  recourse,  possibly  with  recovery  of  heat 
from a renewable resource. 

EU added value 

The  SSD  maintains  its  added  value,  as  the  sole  legal  instrument  providing  an  EU  wide 
framework  for  soil  protection  from  sludge  use  in  agriculture,  setting  a  minimum  level  of 
harmonisation for control of pollution and health risks. It also promotes a rather inexpensive 
sludge management route.  

3 Directive 2008/98/EC 
4 COM(2022) 541 final 

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However, many Member States have gone beyond the Directive requirements, showing that it 
is  not  the  only  driver  to  limit  contaminants  in  soils  and  sludge  and  that  it  does  not  offer  as 
high a level of environmental protection as in the legislation of some Member States. 

Relevance 

Overall, the SSD continues to be relevant and  it is supported by stakeholders. However, the 
list  of  contaminants  which  it  regulates  would  need  review,  notably  considering  organic 
compounds,  pathogens,  pharmaceuticals,  and  microplastics  which  are  present  in  sewage 
sludge. The risks which they pose when sludge is used on farmland need to be assessed and 
addressed through risk management measures.  

Lessons learned 

The  data  gap  on  the  environmental  impact  and  health  risks  linked  to  sewage  sludge  use  on 
land has hindered maintaining the relevance of the legislation over time. 

In  the  wider  context  of  sustainable  development,  zero  pollution,  climate  change,  and  EU 
policies  of  strategic  autonomy,  there  may  be  synergies  and  trade-offs  between  different 
drivers of choices for sludge management. Applying a mix of techniques, in function of local 
settings,  can  help  maximise  benefits  and  minimise  adverse  impacts  on  the  different 
sustainability dimensions affected by sludge management. As such, maintaining the flexibility 
of choice for sludge management is important. 

It could be explored whether more guidance or instructions on treatment at EU level would be 
opportune,  for  optimised  benefits  in  nutrients  and,  possibly,  energy.  For  regulatory 
simplification,  synergies  could  be  exploited  with  future  waste,  soil  or  water  legislation,  and 
future policies to increase efficiency in nutrient, biomass and energy use. In view of the EU 
Soil Strategy, sludge application onto non-agricultural lands may be examined too.  

Finally, the internal market legal base of the Directive should be reconsidered, since changes 
in the EU treaties have made a specific environmental policy legal base available. 

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