Design and Operation of Membrane Bioreactors in
EuropeJohannes Pinnekamp, Hiroki Itokawa, Christoph Thiemig, Aachen

1Introduction

For decades membrane processes have been used successfully in industry, forleachate treatment or for drinking water purification. The combination of biologicalwaste water treatment by activated biomass and subsequent phase separation by
membranes was described in 1969 for the first time /Stephenson, 2000/. With further
development of the low-pressure technology using immersed membranes, thetechnology of the so-called membrane bioreactor (MBR) has now arrived in municipal
waste water treatment, too. With this process, the conventional final clarification forthe separation of treated waste water and activated sludge is replaced by amembrane separation stage. The nearly germ-free effluent quality and the smaller
footprint are regarded as the most important advantages, compared to conventional
technology. As first German installation of this type for the treatment of municipal
waste water, the Titz-Rödingen waste water treatment plant was commissioned in
1999. High demands on the treated waste water were the background for theapplication of this technology. These demands could be met with the filtrate of the
MBR which did not contain solids and was nearly free of germs. The positive
experience acquired during operation but also extensive promotion of this technology
by environmental politics led to the construction of more installations, such as the
Nordkanal waste water treatment plant, at present the largest municipal MBR in
Europe with a daily waste water throughput of 16,000 m³, which was commissioned
in July 2004 /Engelhardt, 2005/. Since then the installation is a reference object for
MBR technology in municipal waste water treatment and serves national andinternational experts as model. The development of the number of installations, theircapacities and the installed membrane surface areas in Germany since 1999 ispresented in the following diagram.

Number of plants

140.000

12

120.000
100.000

910
880.0006
42

180.000
160.000

13

14

200.000

1

2

2

60.0004

340.00020.000
-

0
1999

2000

2001

2002

2003

2004

2005

2006

Year
Number of plants

Capacity- 111 -

Membrane surface

Membrane surface [m2]16

16Capacity [m3/d]

18

- /2Figure 1:

Development of the number of installations, their capacities and installed
membrane surface areas in Germany since 1999 (exept pilot plants)

Besides complete substitution of the final clarification by a membrane stage, today
the use of a MBR in a hybrid solution in parallel to a conventional waste water
treatment plant is discussed, the largest part of the annual waste water quantity
being treated in the MBR. This process presents the advantage that the costintensive membrane stage is economically exploited. However, in the case of stormwater flow, a partial waste water flow still gets into the receiving water via theconventional plant. The suitability of this process variant in practice is being tested in
The Netherlands /Mulder, 2005/.
This report summarizes the results of a Europe-wide survey of the operators ofmunicipal MBR. For this purpose an extensive questionnaire was sent to a large
number of installations in different European countries. The data collected wererecorded in a database and evaluated with view to technical equipment, operational
conditions, purification goals and success as well as operational problems
recognized up to now and approaches for their solution.
At the press date of the proceedings of this conference, not all of the questionnaires
sent were available for evaluation. Therefore mainly the results collected up to thattime are presented in the following. At present, the DWA committee of experts KA-7
is also collecting detailed data on the utilization of membrane technology for waste
water treatment in Germany. The publication of this data is to be expected in the near
future /DWA, 2006/.

2

Development of membrane technology in municipal waste water treatment

In 2000, more than 500 commercial aerobic MBR were in operation worldwide/Stephenson, 2000/. More than 3/4 of the installations serve for industrial applications,
are in-building installations or small plants for the treatment of waste water fromsingle households. Additional 9 % of the plants are used for the treatment of landfill
leachate. Only 12 % of them treat municipal waste water.
In non-European countries, membrane technology is planned and demanded in themeantime also for large waste water treatment plants as best available technology to
improve the water quality and to protect the drinking water resources. This is thecase e.g. on the Arabian Peninsula and in the U.S.A., where some MBR are plannedor already under construction which will exceed the design capacity of the Nordkanal
waste water treatment plant /Engelhardt, 2005/. But in our direct neighbourhood, The
Netherlands, too, a MBR for the treatment of the waste water from 91,000 inhabitants(1,400 m³/h) is under construction. The following diagram presents the numerical
distribution of municipal MBR and the waste water volume treated daily in Europe.

- 112 -

- /3-FRA
5

Others
9

ESP
7

FRA
3%

Others
17%

ESP
5%

Total
ITA
10

Figure 2:

GER
13

83 plants

Total

302 x10
ITA
19%

UK
39

GER
27%
3

m 3 /dUK
29%

Numbers of MBR for the treatment of municipal waste water (left and waste
water volumes treated daily (right) in Europe

Germany and Great Britain take the leading role in Europe concerning the utilizationof MBR for the treatment of municipal waste water. Meanwhile 13 municipal MBR(except pilot plants) with a total capacity of approx. 80,000 m³/d are working inGermany. These figures are exceeded only by Great Britain where MBR have been
applied since the middle of the nineties for the treatment of municipal waste water.
In 2003, already 22 installations with a total waste water throughput of approx.
88,000 m³/d were under construction or in operation in this country /Cranfield Univ.,
2006/.

3

Europe-wide survey with operators of municipal MBR

3.1

Description and way of proceeding

The project started with an investigation in the different European countries in order
to collect the contact data of the relevant installations. For the collected data, noclaim for completeness is made. In parallel with the investigation, a questionnaire in
English language was developed. It contained 51 questions to collect information ontechnical equipment, operation and operating problems recognized up to now. Since
it was asked partly for sensitive data, the operators were assured of anonymoustreatment of the data collected. For this reason no names of installations are
mentioned in the following text. The subject areas recorded by the questionnaire arecompiled in Table 1.
Since the aim was an inventory of large-scale application of MBR in municipal waste
water treatment, only installations with a daily waste water volume of at least 1,000
m³ and a minimum period of operation of one year were considered. On this basis,
25 MBR operators from seven countries in total were contacted. Some German and a
Dutch plant could be visited directly which made it easier to collect data. 14 operatorscompleted the questionnaire and sent it back. Unfortunately it was not possible tomove the operators of the remaining plants to co-operate. Therefore data from the- 113 -

- /4operation of three additional plants, although with less details, were taken fromliterature as an alternative. Thus data from 17 large-scale MBR for the treatment ofmunicipal waste water were available on the whole.
Table 1:

Contents of the questionnaire

Subject areas

Basic data

Design data

Address/contact data
Drainage system
Connected inhabitants
Date of commissioning

Reason for the choice of the MBR process
Number of lines, design flows, part ofindustrial waste water
Pretreatment, configuration of the biologicalstage, type and total surface area of themembranes, design flows, sludge treatment

General information

Subject areas

Operational data
Water quantities treated, influent and effluent
concentrations, operating conditions of thebiological stage and the membrane stage,
membrane cleaning, measuring technology,
operational problems and solutions (sieving,silting, sticking of fibrous material, floating
sludge, etc)

3.2

Results of the survey

Investment and operating costs
Energy consumption
Potential for optimization
General satisfaction with the process
Perspectives according to the operators

Within the scope of the survey concerning installations with a capacity of at least
1,000 m³/d, the ratios of the numbers of installations and capacities are similar to thetotal numbers in Europe (see Figure 2). Figure 3 shows on the left side the number ofplants divided up into size classes. On the right side, the cumulated frequency ispresented using the connection size. Again it becomes clear that Great Britain andGermany play the leading roles in Europe. The majority of the installations are in therange between 1,000 PE and 50,000 PE. The three largest installations of Europe
are in Germany, Italy and Great Britain.

- 114 -

- /5-

8

100
Germany
UK
OthersNo. plants

6

Germany
Cumulative frequency [%]

7

5
4
3
2
1

UK

80

Others60
40
20

0-1,0001,00010,000

10,00050,000

50,000-

0
100

1.000

Capacity [PE]Figure 3:

10.000100.000

Capacity [PE]

Plant capacities in different size classes according to population equivalents(PE) (left) and cumulated frequencies depending on the connection size (right)

For most operators, the reason for the choice of the MBR process was the smaller
footprint, followed by the improved effluent quality. In some cases the plants served
as demonstration object in the respective country in order to acquire first experience
with the technology or to make the introduction of MBR technology to the market
easier.
3.2.1 Inflow conditions
The ratio of the maximum dry weather flow per hour or the maximum storm-waterflow related to the mean dry weather flow respectively is an important factor for thedesign of a MBR because the necessary membrane surface area has to be
calculated according to the maximum inflow water quantity. The higher this ratio, themore unfavourable is the capacity utilization of the membranes which are aconsiderable part of the investment costs. These rations are represented in Figure 4.
For four installations, the ration is nearly 1, thus optimal for MBR operation. In themost unfavourable case, the inflow during storm-water flow is higher by the factor 7
than the mean dry weather inflow.

Cumulative frequency [%]

100
80
60
40
Dry weather

20

Wet weather
0
0

1

2

3

4
Peak factor [-]- 115 -

5

6

7

8

- /6Figure 4:

Ratio of dry weather peak or storm-water peak respectively and mean dry
weather flow

3.2.2 Pretreatment
Pretreatment measures are essential for MBR operation, since the membrane
modules, depending on the type, are susceptible to silting or sticking of fibrous waste
water
contents.
Thefollowing
diagramsinFigure5
showthe„conventional“ pretreatment measures such as coarse screen, grit chamber/grease
trap and primary clarification (left) as well as the slot widths of fine sieves for waste
depending on the membrane type used (right).
100

Flat sheet

80

Hollow fiber

100
80

[%]

60

none

60

2.5~

[%]

40
20

1.0~2.540~1.0

Figure 5:

OthersPrimary
sedimentation

Coarsescreen

Oil
trap

Grit
chamber0200Flat sheet

Hollow fiber

Conventional pretreatment measures (left) and fine sieving of the waste water
depending on the membrane type used (right)

It can be seen clearly that smaller slot widths are normally used in plants equippedwith hollow-fibre modules because these modules are more susceptible to sticking
and clogging of fibrous material.
Besides the pretreatment steps presented, some operators of hollow-fibre modules
additionally use a so-called bypass sieving of the activated sludge. This means that a
partial flow of the recycled sludge is submitted to sieving with slot widths of > 0.5 mm
in order to remove more inhibiting substances from the bioreactor.
3.2.3 Operation of the activated sludge stage
The process of upstream denitrification predominates when choosing the operating
mode of the plants with view to carbon and nitrogen removal. In Great Britain, mostplants are continuously aerated, since in this country no demands are usually madeon the effluent values for nitrogen and phosphorus (Figure 6, left). Only one of theplants was designed for increased biological phosphorus removal. In the plants
where the phosphorus effluent values are controlled by precipitation, no special
precipitant is used (Figure 6, right).

- 116 -

- /79Figure 6:

7

Fullaerobic
7

Total
17 plants

With
P-precipitation

6
5
4
3
2
1

Bio-P

Intermittent
aeration

Predenitrification0
Full
aerobic

Predenitrification
8

Without
P-precipitation

8

No. plants

Intermittent
aeration
1

Bio-P
1

Operating mode of the plants: total numbers (left) and with/without P
precipitation (right)

The solid matter concentrations in the activated sludge tank of the plants on theEuropean continent are predominantly between 10 and 12 g/l. In Great Britain, thesevalues are between 7 and 15 g/l. Concerning the hydraulic retention time which isfrequently used in the design of a MBR /MUNLV, 2003/, the data vary significantly.
Related to dry weather flow, they are between 2.8 and 16 hours (Figure 7, left). But
these retention times not always coincide inevitably with the critical design case.
100
Cumulative frequency [%]Cumulative frequency [%]

100
80
60
40
For capacity

20

80
60
40

With
separate filtration

20

Without
separate filtration

For daily average
0

0
0

10

20

30

Biological stage HRT [h]Figure 7:

0

5

10

15

20

Total HRT for capacity [h]Hydraulic retention times: activated sludge tank only (left) and including
filtration stage (right)

In Figure 7 (right), the retention times including the volumes of separate filtration
tanks are presented. It is striking that the plants equipped with a separate tank for themembrane modules (55 % of all plants) not inevitably require a larger total tankvolume (resulting in a longer retention time).

- 117 -

- /83.2.4 Operation of the membrane stage

100

100

80

80

Cumulative frequency [%]Cumulative frequency [%]The flow rates which can be attained on average are another important factor for theassessment of the cost-effectiveness of a MBR. In Figure 8 (left), the average flow
rates determined by calculation and the maximum flow rates attained briefly under
wet weather conditions are presented. The broad range of these values shows here,
too, significant site-specific differences (cf. chapter 3.2.1 Inflow conditions). On theright side, the specific air requirement for the control of the covering layer isrepresented. The higher air requirement of the plate modules becomes clear.
However, the manufacturers currently develop modules to reduce these values
because this co-called cross-flow aeration has a decisive share in the overall energy
costs.

60

40

Maximum flux

20

60

40

20

Flat sheet

Daily average flux

Hollow fiber

0

0
0

20

40

60

2

0,2

0,4

0,6

0,8
3

1,0

2

Specific air requirement [Nm /m /h]

Flux [L/m /h]

Figure 8:0,0Flow rates (left) and air requirement for covering layer control (right) dependingon the membrane system used

Concerning membrane cleaning, one distinguishes two strategies. The so-called
maintenance cleaning is carried out in intervals of one or two weeks in order tomaintain the permeability, i.e. the filtration capacity of the membrane. An oxidative
cleaning solution (mostly NaOCl) is introduced into the membrane from the permeate
side. Most of the operators carry out an acid cleaning as second step.
In most of the plants, a so-called recovery cleaning is carried out once up to fourtimes a year to counteract the inevitably progressing reduction of the permeability.
This is done in nearly the same way as the maintenance cleaning described above,
but with cleaning agents in higher concentrations.
Irrespective of the strategy, cleaning can be carried out in different ways. With in-situ
cleaning, the membranes remain immersed in the activated sludge. Better cleaning
results are attained with the so-called on-air cleaning. For this purpose, the modules
remain in the tank and the sludge level is lowered to the bottom edge of the module.
This procedure requires separation of the tank zones (activation zone – filtrationzone). The best cleaning results are attained with the so-called soaking. This meansthat the modules are immersed completely for several hours into a cleaning solution.

- 118 -

- /9However, either the activated sludge has to be removed and the cleaning solution
has to be filled into the membrane chamber, which requires a corresponding
arrangement of the tanks like in on-air cleaning. Or the modules are lifted from theactivated sludge tank into a separate washing cell where the cleaning takes place.
Since this is the most expensive cleaning method, it is only used for recovery
cleaning.
Two of the 17 plant operators questioned told us that they carry out the cleanings
described with H2O2 instead of NaOCl. This proceeding has the advantage that theeffluent is not charged with organic halogenated compounds. However, the otheroperators still prefer NaOCl as cleaning agent because of better cleaning results intheir plants.
Concerning membrane cleaning, there are clear differences depending on themembrane system used. Hollow-fibre membranes are usually cleaned by a
combination of maintenance and recovery cleaning, while it is done withoutmaintenance cleaning for plate membranes. Table 2 presents the cleaning methods,
chemicals and their concentrations depending on the membrane system as well as
data on the operating cycles of the membranes of eleven different plants.
Table 2:

Maintenance cleaning

Betriebszyklen

Kläranlage
Membrantyp

Cleaning strategies depending on the membrane system
1
PlatteRecovery cleaning

3
Hohlfaser4
Hohlfaser5
Hohlfaser

6
Hohlfaser

7
Hohlfaser8
Hohlfaser9
Hohlfaser10
Hohlfaser

11
Hohlfaser

Filtrationszeit [s]

540

400

200

500

k.A.

k.A.

300

k.A.

k.A.

360

300

Pause [s]60 (+30s)

0

0

1

k.A.

k.A.

0

k.A.

k.A.

0

5

Rückspülung [s]

-

15

50

k.A.

k.A.

30

k.A.

k.A.

20

25

Methodenie

50
On air +In-situ

On airOn airIn-situIn-situIn-situIn-situIn-situ

On airOn airFrequenz-

1/Woche0.51/Woche

ErstesReinigungsmittel-

Zitronensäure(+HCl)

NaOCl

Konzentration [ppm] -pH=2

Zweites
Reinigungsmittel

NaOCl

-

Konzentration [ppm] -Grundfür RC2
Hohlfaser

500

250-500
Zitronensäure
jeweils
berechnet

Soaking(sep.Tank) 1/Jahrnie
Zitronensäure(+HCl)

0.5/Woche 1/Woche k.A.
NaOCl
(1+2.
Woche)
Zitronensäure(3. Woche) H2O2
H2 O 2k.A.

1/Woche

NaOCl

NaOH

NaOCl

NaOCl

NaOCl

700
(NaOCl)
30000(Zitronensäure)

k.A.

200

k.A.

500

800

250

k.A.

Zitronensäure

Zitronensäure

k.A.

k.A.

Zitronensäure

HCl

300

k.A.

k.A.

k.A.

k.A.

k.A.

3200

675

Soaking(in situ)
2/JahrSoaking(sep.Tank) 1/Jahrnie

Soaking(in situ)
1/JahrSoaking(sep.Tank) k.A.
k.A.
2/Jahrnie

Soaking(in situ)
1-2/Jahr

NaOCl

-

NaOCl

k.A.

NaOCl

-

NaOCl

Zitronensäure-

Zitronensäure

k.A.

k.A.

-

Zitronensäure

0
1
0

k.A.
k.A.
k.A.

0
0
1

1
0
0

k.A.
k.A.
k.A.

0
0
1

1
0
0

300
Zitronensäure(+HNO3)

MethodeFrequenz

Soaking(in situ)
4-5/Jahr

ErstesReinigungsmittel

NaOCl

Zweites
Reinigungsmittel

Oxalsäure
(C2O4H2) NaOCl-

H2 O 2Zitronensäure(+HNO3)TMP
fester Zeitpunkt
Andere

1
0
1

0
0
0

0
1
0

0
0
1

1/Woche

1/Woche(Winter)
0.5/Woche(Sommer) 1/Woche- 119 -

- / 10 3.2.5 Purification capacity
Figure 9 (left) presents the ratio of the maximum inflow concentration and the meanvalues. The inflow concentrations in part vary significantly. The average COD inflow
concentrations are in a range between 232 mg/l and 700 mg/l. The COD peak load
also shows a broad range (from 508 mg/l to 2140 mg/l). This also applies for thenitrogen and phosphorus concentrations. Nevertheless, all MBR are able to efficiently
remove organic substances and nutrients. Nearly all plants attain average COD
removal rates of > 90%. Figure 9 (right) presents the removal rates for COD, total
nitrogen and total phosphorus as cumulated frequencies.
100
Cumulative frequency [%]Cumulative frequency [%]

100
80
60
40
COD
T-N

20

T-P
0

T-N
T-P

60
40
20
0

0

2

4

6

Influent peak/average ratio [-]Figure 9:

COD
80

0

20

40

60

80

100

Average removal efficiency [%]Ratio of inflow concentrations (left) and removal capacity (right)

3.2.6 Operating problems, approaches for solutions and need for optimization
When introducing a new technology, most different operating problems usually occur
during the first years which cannot be foreseen or only to a limited extent when
designing the plants. In the case of MBR, the following “classical” operating problems
with possible approaches for solutions can be identified:x

Problems with fine sieving of the waste water Î to be optimized by the screen
manufacturers (in cooperation with the operators)x

Problems with the membranes due to insufficient fine sieving of the waste
water (sticking of fibrous material) Î change of the type of sieve, reduction of
the slot widths, sieving of partial sludge flowsx

Problems with the membranes by insufficient aeration (silting) Î optimizationof module aeration or to be optimized by the module manufacturerx

Damages at the membrane modules Î to be optimized by the module
manufacturer, more careful handling of the modules during operation andcleaning- 120 -

- / 11 x

Strong development of floating sludge Î skimming, spraying, utilization ofpolymers, “ignoring“xAir in the permeate pipe Î constructing the permeate pipes ascending to thepump, vacuum pumpx

Problems with the control software Î to be optimized by the software
producer in cooperation with the operators

Besides these general operating problems, some special proposals and remarks ofthe operators should be considered when planning MBRs:x

The membrane modules should be arranged in separate tanks. The
advantages of cleaning compensate the disadvantages from operationx

The permeate pipes should be designed as short as possible in order toreduce the periods of backwashing.

x

The number of racks per unit should be small, and the permeate pipes to theunits should have uniform lengths. This ensures homogeneous feeding of themembranes with the cleaning solution.

x

The permeate pipes should be made of plastic. This helps to avoid corrosion
due to cleaning agents.

From the operators’ point of view, there is still general need for optimization of theplant operation. The above problems and remarks were the most frequently
mentioned ones and, with this, at the same time an appeal to the researchers:

4x

To lower the energy demandx

To optimize the pretreatment in order to ensure stable MBR operationx

To make chlorine-free cleaning possible

Summary and outlook

Within a few years, the MBR technology has become a promising alternative forconventional technology. At present, more than 80 large-scale MBRs are in operationin Europe. Some more large-scale plants are in planning stage or already underconstruction.
The survey carried out had for result that most of the operators are quite satisfied
with the efficiency of their plants. The operating problems mentioned areunderstandable, since the technology is still new, but they seem solvable. For thispurpose, however, plant operators, membrane manufacturers, consulting engineers
and research institutions have to cooperate closely. In Germany, approaches in thisfield already exist. Within the framework of conferences and workshops, organized by- 121 -

- / 12 university institutes, water boards or DWA, engineers and scientists get theopportunity to exchange and discuss their experience. First publications give
instructions for design and operation of MBRs. The book “Membrane Technology for
Waste Water Treatment”, edited by MUNLV NRW /MUNLV, 2006/ and the work
reports of the committee of experts KA 7 of DWA /DWA, 2005/ are to be mentioned
here. The development of an internet-based data base for the collection of all
relevant data in this field would be a possibility to improve cooperation in Europe.
These data might serve as ideal basis for coordination and planning of additional
research activities.
With the construction of the Nordkanal WWTP, it was demonstrated that the MBR
technology can be mastered on a large scale and can be used efficiently. The
question is now: Which perspectives has this process concept in Europe? The
political and legal boundary conditions concerning the demands on the effluent
quality will surely influence the membrane market in a positive way. Within thesebounds, the IVU and the Water Framework Directive have to be mentioned. Thus it
can be expected that the number of membrane installations in Europe will increasesignificantly from 2010 on within the scope of the implementation of water protection
measures. The reasons are not only the high capacity for nutrient removal and thenearly germ-free effluent quality of MBRs. Since it is aimed at reducing priority
substances in surface waters, the solid-free effluent, ensured by the membranes,
offers ideal prerequisites for the use of downstream treatment steps such as
ozonation or active carbon filtration.
The market research institute „Frost & Sullivan“ has found out that the biggest
challenge for the membrane manufacturers is to persuade the decision-maker in themarket of the possibilities of the MBR process and to show them which benefit thecustomer may derive from them /Frost & Sullivan, 2005/.
Integration of the MBR into the conventional technology, as it is the case with thehybrid solution, or complete replacement of the final clarification by the MBR – from
European legislation concerning purification requirements, but also from the purely
technical advantages of the process it can be expected that the market for MBR in
municipal waste water treatment in future will increase.
Acknowledgements:
We express our thanks the participants of the survey who have compiled allnecessary data for the extensive questionnaire and who have given information in apatient way during long conversations, and the Federal Ministry of Education andResearch for the promotion of the project.

- 122 -

References:/Cranfield Univ., 2006/ Cranfield University, UK:
http://www.cranfield.ac.uk/sims/water/memnet/uk_membrane_municipal_plant.html, Last access:January 2006
/DWA, 2005/

Deutsche Vereinigung für Wasser, Abwasser und Abfall e.V.,
DWA: 2. Arbeitsbericht des Fachausschusses KA-7
“Membranbelebungsanlagen, KA – Abwasser, Abfall 2005(52) Nr. 3; ISSN 1616-430X, (2005)/DWA, 2006/

Deutsche Vereinigung für Wasser, Abwasser und Abfall e.V.,
DWA: Auskunft des Fachausschusses KA-7, (2006).

/Dohmann, 2005/

Dohmann, M: Perspektiven für den Einsatz der Membrantechnik in der Abwasserbehandlung, Beitrag zur 6. Aachener
Tagung Siedlungswasserwirtschaft und Membrantechnik(2005)/Engelhardt, 2005/

Engelhardt, N: Das Gruppenklärwerk Nordkanal nach einem
Jahr Betrieb – eine Perspektive für große Membranbelebungsanlagen, Beitrag zur 6. Aachener Tagung Siedlungswasserwirtschaft und Membrantechnik (2005)/Frost&Sullivan, 2005/ Frost & Sullivan Research Report: Strategic Analysis of theEuropean Membrane Bioreactor Markets (2005),
http://www.frost.com/Mulder, 2005/

Mulder, J. W., v. d. Berkmortel, H., Kramer, F.: Hybrid-MBR –Ein neues konzept für die Abwasserbehandlung, Beitrag zur
6. Aachener Tagung Siedlungswasserwirtschaft undMembrantechnik (2005)/MUNLV NRW, 2006/

Ministerium für Umwelt und Naturschutz, Landwirtschaft undVerbraucherschutz des Landes Nordrhein-Westfalen:
Membrantechnik für die Abwasserreinigung, Erschienen im
FiW-Verlag, ISBN 3-939377-00-7 (2006)/Stephenson, 2000/

Stephenson, T., Judd, S. J., Jefferson, B., Brindle, K.:
Membrane Bioreactors for Wastewater Treatment. IWA
Publishing, London (2000)/Stephenson, 2003/

Stephenson, T.: Membrane Technology for Wastewater
Treatment and Reuse - State of the Art and future
Prospectives, Beitrag zur 5. Aachener Tagung Siedlungswasserwirtschaft und Membrantechnik (2003)- 123 -

- 124 -Environmental Engineering RWTH Aachen University

Environmental Engineering RWTH Aachen University

Design and Operation of Membrane Bioreactors in Europe¨ Far more applications in a range of industries(e.g. textile, brewery, food...)¨ Typically applied in conjunction with water reuseIndustrial WWT¨ First application in 1999 (Rödingen WWTP, 3,000 PE)¨ Presently, 12 plants are operated, 4 plants are underconstruction/design¨ Principal reasons for application are to meet the effluent
quality regulation and to reduce tank volume

Municipal WWT

MBR application in Germany

Design and Operation of Membrane Bioreactors in Europe

Institute of Environmental Engineering
RWTH Aachen University

Univ.-Prof. Dr.-Ing. Johannes Pinnekamp
Dr.-Eng. Hiroki Itokawa
Dipl.-Ing. Christoph Thiemig

Design and Operation of
Membrane Bioreactors in Europe

3

1

Environmental Engineering RWTH Aachen University
Environmental Engineering RWTH Aachen University

kWh/m³Specific energy
consumption

2004
2004

Seelscheid

10,5002,600

80,000

700

9,700

2,310

730

9,200

136

1,640

68

1,800

190

480

Kubota

ZENON

ZENON

PURON

ZENON

Martin Systems

ZENON

KubotaZENON

ReactorMembranevolume [m3]supplier

Design and Operation of Membrane Bioreactors in Europe

2003

Nordkanal
Schramberg

2003

Monheim

2003

2001
Simmerath

8,000

2000

Markranstädt
Knautnaundorf

900

1,000

1999

Büchel3,000

Capacity[PE]
1999

Start-up
Rödingen

Name

Existing municipal MBR plants in Germany

Design and Operation of Membrane Bioreactors in Europe

0.7 – 1.5

< 20

<5

g/L

MLSS

0.2 – 0.4

bathing water quality

mg/L

Ptot (with simultaneous
precipitation)
No bathing water
quality

< 13

< 13

mg/L

Ntot

Microbiological quality< 30

40 – 50

mg/L

COD

< 0.3

0

10 – 15

mg/L

Suspended Solids

0.8 – 1.0

Membrane Bioreactor

Conventional activatedsludge plantParameter

Performance data of membrane bioreactor plants
compared to conventional activated sludge plants

42

- 125 -Environmental Engineering RWTH Aachen University

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5

Source: Erftverband 20027

Conventional plant

Design and Operation of Membrane Bioreactors in Europe

Membrane bio-reactor plant

Example of municipal MBR application(Nordkanal)
Nordkanal)

Design and Operation of Membrane Bioreactors in Europe¨ Increased requirements for the effluent quality- EU Water Framework Directive- EU Directive on Bathing Water- Sensitive receiving water bodies- WWTP effluent in drinking water protection zones¨ Local situation (space requirement)¨ Introduction of new technology¨ Financial support by local governments¨ Technical improvement of immersed membrane
modules¨ Increased knowledge & experience from existingplans

Driving forces for MBR application inGermany
Environmental Engineering RWTH Aachen University
Environmental Engineering RWTH Aachen University

Step screen
5 mm
Emergency
bypassscreen1 mm

Rotaryscreen0,5 mmRecirculation

Nitrification,
membrane stage

Blowerinstallation

Flow

mg/l
mg/l
mg/l

NH4-N
Ntot
Ptot

< 0,5

?

<2

<5

< 25

Discharge consent(at T<10°C)

6Design and Operation of Membrane Bioreactors in Europe

Source: Erftverband 20028¨ An energy demand approx. 60 % (0.8 kWh/m³) higher than forconventional plants (0.51 kWh/m³) can be expected¨ The investment was 21.5 million €.
¨ Approx. 6.6 million € of this amount had been taken over by thefederal state North-Rhine Westphalia.

2

18

10

90
20

mg/l
mg/l

Minimum
requirements
BOD5

Unit
COD

Parameter

Minimum requirements and discharge consent of the Nordkanal WWTP

Example of municipal MBR application(Nordkanal)

Design and Operation of Membrane Bioreactors in Europe¨ Largest in Europe(80,000 PE = approx.10,000 m3/d, 84.000 m² membrane surface)¨ Operated since December 2003

Feed

Grit
chamber

Denitri- Variablefication zone

Example of municipal MBR application(Nordkanal)

- 126 -

1

2

2

3

4

9

Number of Plants

1999

2000

2001

2002

2003

2004

2005

2006

(Without pilote plants)
Design and Operation of Membrane Bioreactors in Europe02020.00040.00060.0006

480.000100.000

120.000

8

10

12140.000

14
13

160.000

16

18

16

180.000

Membranfläche
Membrane
Surface200.000

Kapazität
Capacity

20

Anlagenzahl
Number of Plants

Development of Plant Number in Germany

Design and Operation of Membrane Bioreactors in Europe

Capacity [m3/d] Membrane area [m2]11

9Environmental Engineering RWTH Aachen University
Environmental Engineering RWTH Aachen University

Environmental Engineering RWTH Aachen University

Environmental Engineering RWTH Aachen University

WWTP Kaarst/Nordkanal

Numberof Plants
Anlagenzahl

2

2

3

5

9

13

Capacity
Kapazität

20

41

61

82

Membrane Surface
Membranfläche

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

1

Design and Operation of Membrane Bioreactors in Europe(Ohne Pilotanlagen)Without
Pilote Plants

0

10

20

30

40

50

60

70

80

90

Numberof Plants
Anlagenzahl

040.00080.000120.000

160.000

200.000

240.000

280.000

320.000

360.000

Development of Plant Number in Europe

Design and Operation of Membrane Bioreactors in Europe

Membrane installation at the WWTP
Nordkanal

10

Source: Erftverband 2002

12

Kapazität[m³/d]
Membranfläche] [m²]
Capacity[m³/d]
Membrane
Surface [m²Area- 127 -Environmental Engineering RWTH Aachen University

Environmental Engineering RWTH Aachen University

GER
13

UK
38

3
5

And.
17

ITA
19

%

GER
27

Anlagenzahl
Numberof Plants-1,00010,000-50,000

Capacity [PE]Kapazität[EW]

1,000-10,000

Deutschland
Germany
UK
UK
AndereOthers

50,000-Design and Operation of Membrane Bioreactors in Europe

0

1

2

3

4

5

6

7

8

Size Distribution

UK
29

Capacity
Total: 302,000 m³/d

Design and Operation of Membrane Bioreactors in Europe(Without pilote plants)

And.
9
FRA
5
ESP
7
ITA
10

Number of Plants
Total: 82

15

13

Environmental Engineering RWTH Aachen University
Environmental Engineering RWTH Aachen University

Plant Number and Capacity

10.000Kapazität [PE]Capacity
[PE]

1.000

Germany
Deutschland
UK
UK
OthersAndereDesign and Operation of Membrane Bioreactors in Europe

100

0

20

40

60

80

100

Participants in the Survey

100.000

 Costs
 Optimization Potentials
 Contentedness Perspectives¨ General Information

Design and Operation of Membrane Bioreactors in Europe

 Reason for MBR
 Design Flow Industrial WW Flow
 Number of Lines Pretreatment
 Configuration of Biol. Reactor
 Type and Design ofMembranes Sludge Treatment¨ Design Data

16

14

 Flow
 In- and Outflow Concentrations
 Operational Conditions
y Biological Reactor
y Membranes
 Membrane Cleaning Measuring Operational Problems
 Lessons Learned¨ Operation Data

Content of Questionnaire Address/Contact Data
 Sewerage System
 Capacity
 Start of Operation¨ Basic Data

Kumulierte
Häufigkeit
Frequency[%][%]

- 128 -Environmental Engineering RWTH Aachen University

Environmental Engineering RWTH Aachen University

0

20

40

60

80

0

2

4

Peak Factor [-]Peak factor [-]6

Wet weather

Dry weather

Plattenmodul
Flat
Sheet Mod.

1.0~2.5

keine

Hohlfasermodul
Hollow
Fiber Module

2.5~

Design and Operation of Membrane Bioreactors in Europe

0

20

40

60

80

100

~1.0

Fine Screen as Pre-Treatment

Design and Operation of Membrane Bioreactors in Europe

Cumulative Frequency
frequency [%] [%]Cumulative

Anteil [%]

8

19

17

Grob
CoarserechenScreen

Fett
Oil
fang
Trap

Sand
Grit
fang
Chamber

Anteil [%]Hohlfasermodul
Hollow Fiber M.

Plattenmodule
Flat Sheet Mod.

Total:
17 Plants

1

Bio-P

7

Contin.
aeratedDesign and Operation of Membrane Bioreactors in Europe

PreDenitrif.
8Interm.
Denitrif.
1

Operation of Biological Stage

Design and Operation of Membrane Bioreactors in Europe

0

20

40

60

80

100

Pre-Treatment Technologies

Primary
Vorklärung
Sediment.

100

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Influent Variation

AndereOthers20

18

Environmental Engineering RWTH Aachen University

Environmental Engineering RWTH Aachen University

0

12

18

24

Aufenthaltszeit
in derStage
biologischen
Stufe [h]Biological
HRT [h]6Fordaily Mittel
im täglichen
AverageFor
bezogenauf dieGesamtkapazität
Capacity

0

10

20

30
2

Design and Operation of Membrane Bioreactors in Europe

Flux [L/m /h]

40

50

Daily
Flux Average
im täglichen
Flux
Mittel200Maximaler
Flux
Maximum
Flux

40

60

80

100

Maximum and Average Flux Rates

Design and Operation of Membrane Bioreactors in Europe

0

20

40

60

80

100

Biological Stage HRT [h]

21

23

60

30

Environmental Engineering RWTH Aachen University
Environmental Engineering RWTH Aachen University

KumulierteFrequency
Häufigkeit [%]Cumulative[%]

Kumulierte Frequency
Häufigkeit [%]Cumulative
[%]

0

2

4

6

8

10

Total HRT [h]Gesamtaufenthaltszeit [h]

12

14

0,2

0,6

0,8

Specific
Air Requirements[Nm²/m³/h]
Spezifischer
Luftbedarf [Nm³/m²/h]

0,4

Hohlfasermodul
Hollow Fiber M.

Flat Sheet Mod.
Plattenmodul

Design and Operation of Membrane Bioreactors in Europe

0

20

40

60

80

100

1,0

Air Requirements for Covering Layer Control

16

Module im
Without
separate
Belebungsbecken
Filtration

20
0

With
separate
mit separater
Filtration
Filterstufe

40

60

80

100

Total HRT [h]Design and Operation of Membrane Bioreactors in Europe

KumulierteFrequency
Häufigkeit [%]Cumulative[%]

Kumulierte Häufigkeit]
Cumulative
Frequency[%[%]- 129 24

22

18

- 130 -Environmental Engineering RWTH Aachen University

Environmental Engineering RWTH Aachen University

0

1

2

3

4

Kumulierte Häufigkeit [%]Effluent

Design and Operation of Membrane Bioreactors in Europe

Pretreatment
Optimal MLSS-conc.
Excess sludge production
Sludge properties
Aeration efficiency (α-value)
Hydraulic behaviour(Min. hydr. retention time)
Floc structure, Foaming
Pretreatment
etc….

1. Biological Process

Inflow

Research Topics

Design and Operation of Membrane Bioreactors in Europe

Zulaufkonzentrationen:
Verhältnis Ratio
Spitze/Mittelwert[-]
Influent Peak/Average[-]

5

Total-P

20

0Total-N

CSB

40

60

80

100

6

27

25

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Variation of Inflow Concentrations

0

20

40

60

80

100

20

30
40
50
60
70
80
90
Durchschnittliche[%]
TreatmentEliminationsleistung
Efficiency [%]Total-P

CSB
Total-N

Treatment Efficiency [%]Material
Pore size
Flow, permeability
Fouling, scaling
Cleaning
Costs
Life spanetc….

2. Membrane

Effluent

Design and Operation of Membrane Bioreactors in Europe

Inflow

Research Topics

Design and Operation of Membrane Bioreactors in Europe

Cumulative[%]
Kumulierte Frequency
Häufigkeit [%]

100

28

26

- 131 -Environmental Engineering RWTH Aachen University

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Post-treatment
etc….

Degradation
Transformation
Adsorption
Filtration

MembraneMembrane
Replacement
Costs [€/m²]
replacement costs €/m2

1995
Year

Year

WWTP Markranstädt
8.000 E
joint WWTP
Nordkanal
80.000 E

WWTP
Knautnaundorf
900 E

2000

WWTP Rödingen
3.000 E

according to Churchhouse(2000)

Design and Operation of Membrane Bioreactors in Europe

0
1990

50

100

150

200

250

300

350

400

450

Cost Development

2005

Conventional parameters
Hygienic quality
Organic trace pollutants
Mechanisms

3. Treatment Efficiency

Effluent

Design and Operation of Membrane Bioreactors in Europe

Inflow

Research Topics

31

29

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Energy Demand
Costs
Life Cycle Analysis
Automation and Control……….

4. Whole Process

Effluent

Design and Operation of Membrane Bioreactors in Europe

Design and Operation of Membrane Bioreactors in Europe

Inflow

Research Topics

3230