Your wastewater treatment plant.

Built with advice and solutions from WABAG.

From A to Z.

Water is not always as clean as it should be.

And that's where WABAG comes in.

Your specialist contact for water treatment plants.

The latest technologies.

Developed by WABAG in Switzerland.

For economical, environmentally friendly and reliable wastewater treatment.

We go all out.

To make life easier for you.

Day after day.



Returned to nature as clean as possible.

«Effective wastewater treatment is the key to healthy water, not only to provide us with drinking water but also so that water can be treated and reused right away. WABAG Wassertechnik AG offers innovative solutions that are tailored to the needs of specific projects. The primary objective, alongside high-quality engineering, is to achieve maximum customer satisfaction.»

Gerhard Ryhiner - COO / Head of Wastewater Technology

COO / Head of Wastewater Technology

Gerhard Ryhiner

Frank Marcel - CFO / Head of Execution

CFO / Head of Execution

Marcel Frank


Preliminary Treatment.

WABAG - Vorreinigung


Preliminary treatment.

MICROPUR is an advanced mechanical preliminary treatment method. This innovative fine sieving process takes the pressure off downstream treatment processes by reliably removing coarse contaminants such as hair and fibers from the wastewater. In addition, it significantly reduces suspended solids and, in turn, other unwanted nutrients. When used upstream of a biological treatment process, it can achieve a degree of screening that is equivalent to that of primary sedimentation but without taking up anywhere near as much space. The MICROPUR process is the ideal addition to plants that already employ a membrane bioreactor (MICROPUR-MBR) or other biological treatment methods.

Key Features

  • Facilitates biological treatment by reducing suspended solids and unwanted nutrients
  • Cuts the amount of energy required for biological wastewater treatment
  • Increases gas production during digestion
  • Increases operational safety
  • Facilitates sludge thickening
  • Takes up minimal space

WABAG Specialty

The MICROPUR drum sieve was developed in house by WABAG and successfully tested in Switzerland at the Uerikon municipal water treatment plant


ARA Ujams

5'100 m³/d


Biological Treatment.

Wabag Biologische Reinigung

BAF – BIOPUR® (Biofiltration).

Biological treatment.

BIOPUR is a biofiltration system developed by WABAG for the biological treatment of wastewater. It uses biofilms – which are cultivated on solid surfaces – to biologically degrade the pollutants in the wastewater. At the same time, suspended solids are captured by the filter materials. BIOPUR is a modern and space-saving process that is capable of meeting the toughest of water treatment requirements in both municipal and industrial contexts.

The carrier materials and filter media are tailored precisely to water treatment needs and so the system is completely customizable for a multitude of applications. The system can be effectively combined with other treatment methods such as tertiary filtration, making it ideal for plants that are tasked with removing micropollutants.


  • Highly compact
  • Suitable for enclosed plants with minimum emissions
  • Highly flexible when faced with hydraulic fluctuations and organic load variations, and when combined with other process stages
  • Highly automated operation

WABAG Specialty: Filter Media

The defining features of BIOPUR are its filter media, which consist of both structured packing and granulate. As different carrier materials are available and can be combined in different ways, we can select a biofilter that is perfectly matched to your requirements.



ARA Meilen

55'000 EW
450 m³/h

ARA Limmattal

110'000 EW
3'600 m³/h


ARA Worblental

140'000 EW
2'950 m³/h


MBBR/IFAS – FLUOPUR® (Moving Bed).

Biological treatment.

FLUOPUR is the name of WABAG's moving bed process for the biological treatment of wastewater. It can be used as a moving bed (MBBR) on its own or in combination with activated sludge (hybrid or IFAS). The patented carrier material, which was developed by WABAG, is used to cultivate biofilms that are also capable of performing other tasks according to requirements.

The FLUOPUR process requires less space than conventional activated sludge treatment and virtually any tank geometry can be selected. That makes FLUOPUR ideal for extending existing activated sludge processes when they hit capacity bottlenecks or need to meet more stringent purity requirements.

Key Features

  • Flexible, straightforward, space-saving system
  • Cost-effective solution for a whole host of applications and plant sizes
  • Ideal for extending existing plants (while making use of existing aeration equipment)
  • Ideal for industrial wastewater (preliminary/full/
    secondary treatment)

WABAG Specialty: FLUOPUR Carrier Material

The FLUOPUR carrier material has been developed by WABAG based on many years of experience. Its defining feature is its really straightforward fluidization concept, which supports fine-bubble aeration and enables the air input to be matched to the effective oxygen demand. This results in huge energy savings, particularly under light-duty conditions. What's more, it encourages the growth of biofilms with optimum characteristics so that the available surface area can be utilized for a very long time.

The low carrier volume means that the tank does not need to be filled very high, thereby ensuring considerable operational flexibility. In addition, the carrier can be easily pumped out of the way if an inspection needs to be carried out.

The mesh has been specially designed to complement the carrier material and rounds off the FLUOPUR package.



STEP Vuippens

80'000 EGW
1'360 m³/h

ARA Illanz

25'000 EGW
9000 m³/h

Dona Imelda WWTP

20'000 EGW
450 m³/h

MBR – MARAPUR® (Membranbioreaktoren)

MBR – MARAPUR® (Membrane Bioreactors).

Biological treatment.

Membrane bioreactors (MBR) are powerful systems for the biological treatment of wastewater. The biological treatment stage performs a similar role to a conventional activated sludge system. However, in this case, the activated sludge and clean wastewater are not separated in a secondary sedimentation tank by the force of gravity but are separated using membrane filtration. As a result, the filtrate contains no solid matter and virtually no bacteria and microorganisms. In addition, the concentration of the sludge in the activated sludge tanks is not limited by the performance of the secondary sedimentation system, allowing you to work with higher sludge concentrations. This results in complete solutions that are highly compact.

Membrane bioreactors are often the technology of choice for meeting stringent purity requirements. However, they can also be used very effectively to boost the performance of existing plants. Membrane bioreactors are suitable for municipal and industrial wastewater treatment applications, and are also a key technology for the reuse of water. A specific preliminary treatment method (particularly in the form of MICROPUR) can be incorporated and appropriate operation ensured to create a membrane filtration solution that is both straightforward and economical.


  • Highly efficient system with minimal space requirements
  • The clean wastewater is of superb quality and is ideal for sensitive receiving waters
  • High operational safety even in the event of load changes
  • Better degradation of micropollutants
  • Easy extension of existing plants
  • Perfect in combination with MICROPUR

WABAG Specialty: Optimized Operation

MBR systems from WABAG stand out on account of their innovative concepts, which are geared toward specific projects. Typical objectives might be to optimize energy consumption and extend the life of the membranes.

WABAG is a leader in the field of membrane bioreactors and can offer exactly the right solution for any application thanks to its range of different systems. Through R&D, we are constantly building on our many years of experience in the operation of large-scale MARAPUR plants.


ARA Zermatt

60'000 EW
1'008 m³/h

ARA Wädenswil

22'00 EW
612 m³/h

ARA Uerikon

7'000 EW
260 m³/h

SBR – CYCLOPUR® (Sequencing Batch Reactor)

SBR – CYCLOPUR (Sequencing Batch Reactor).

Biological treatment.

SBR is a system for the biological treatment of wastewater. In contrast to conventional activated sludge processes where the wastewater is treated by passing it through a series of tanks, the SBR method involves carrying out the different steps one after another in the same tank.

As the reactors are filled on a batch-by-batch basis, several SBR tanks and/or an influent buffer tank are required to treat wastewater continuously. On the other hand, there is no need for the recirculation equipment that goes hand in hand with continuous systems, and the cleaning performance can be flexibly and perfectly adapted to requirements. The typical steps involved in the process are:

  • Fill (mixed or aerated)
  • Reaction: aeration or mixing
  • Sedimentation
  • Decantation: extraction of the clean water

Key Features

  • Ultraflexible
  • Suitable for all types of wastewater and sizes of plant

WABAG Specialty: WABAG Decanter

The WABAG swivel-joint decanter has been designed by drawing on a wealth of experience from a variety of projects and is produced by us in house. The model is in use at several plants, both inside and outside of Switzerland. Its defining features include a maintenance-free stainless steel swivel joint and the optimized hydraulics.


ARA Buttikon

12'500 EW
345 m³/h

ARA Flims

18'000 EW
446 m³/h

ARA Uster

48'000 EW
2'880 / 4'320 m³/h

GAS – Nereda®

Aerobic Granular Sludge – Nereda®

Biological treatment.

Nereda is a highly advanced technology for biological wastewater treatment that is based on the SBR method and harnesses the power of aerobic granular sludge. With this technology, the bacteria grow naturally in compact granules instead of in flocs.

These granules have excellent settling properties, the advantages of which are many: the biomass concentration in the reactor is very high, but the sedimentation phase is extremely short. What's more, the reactor can be filled while clear water is being extracted. This results in excellent biological performance and means that virtually all of the cycle time can be spent on biological processes, leading to small reactors with minimal space requirements. Another factor is that many biological processes take place within the compact granules simultaneously. This results in high rates of nitrogen and biological phosphorus removal, and largely eliminates the need for precipitating agents. 

Compared to conventional SBR technology, these systems are much more compact overall and produce a better quality of effluent.

Key Features

  • Compact plants with minimal space requirements (around 50% compared to SBR)
  • Flexibility of a batch process (SBR)
  • High rates of biological nutrient removal
  • A proven and robust process with minimal consumption of resources (energy, chemicals) that is characterized by its ease of operation


WABAG Specialty

The process was developed in Holland by Delft University of Technology and Royal HaskoningDHV and is already being used successfully at numerous municipal and industrial wastewater treatment plants. WABAG Wassertechnik holds the license for the process in Switzerland and India. 

WABAG has tested the procedure in conjunction with Swiss wastewater and, in particular, optimized it for the specific discharge conditions that apply in Switzerland.

Further information about Nereda is available at


ARA Sarneraatal

65'000 EW
1'872 m³/h

ARA Kloten-Opfikon

125'000 EGW
2'880 m³/h


Tertiary Treatment.

Wabag Tertiäre Reinigung
WABAG Filtration

WABAG Filtration.

Tertiary treatment.

Filtration is one of the key processes involved in the treatment of water. The technology was developed in the 1960s – when the company was still called Sulzer – but has undergone continuous enhancement ever since. The origins of wastewater filtration can be traced back to the 1970s. Today, a whole host of systems and filter media are available for various applications:

  • Single- and multilayer filters (in various combinations)
  • Filters with a nozzle floor or drainage system
  • Various designs and modes of operation
  • Various backwashing programs
Wastewater filtration is required whenever the effluent is subject to strict quality requirements, such as in catchment areas for sensitive waters. When combined with other treatment steps, wastewater filtration offers a reliable and cost-effective solution for removing micropollutants or reusing wastewater, for example.

Effective backwashing is crucial to ensuring reliable long-term operation. For this, there is a choice of sophisticated backwashing concepts. Together with the optimized filter construction technology, this leads to excellent results.

Key Features

  • Various designs for ideal solutions geared toward specific projects
  • Optimum filter cleaning thanks to the proven backwashing system that minimizes filter medium losses
  • Biological activity in the filter bed for targeted secondary treatment
  • Various processes can be combined for further treatment

WABAG Specialty: Filter Floor Systems

As well as offering optimized solutions for classic nozzle floors, WABAG also offers its WABAG drainage system, which can – for example – be used in filter renovation work.

Together with the wide range of available filter media, this means that WABAG can come up with the perfect configuration for any project.


ARA Freienbach
WABAG Filtration

45'000 EW
1'800 m³/h

ARA Werdhölzli
WABAG Filtration

670'000 EW
23'400 m³/h

ARA Esslingen
WABAG Filtration

20'000 EW
756 m³/h

ARA Männedorf
WABAG Filtration

18'000 EW
864 m³/h



Wabag Mikroverunreinigungen
BIOZONE® (Ozon +Biologie/Bioaktiver Filter).

BIOZONE® (Ozone + Biological Treatment / Bioactive Filter).

Removal of micropollutants.

The BIOZONE process was originally developed by WABAG for treating wastewater containing a high percentage of organic compounds with low biodegradability. It generally consists of a two-stage biological treatment process with an intermediate oxidation step. The range of application encompasses:

  • The pulp and paper industry
  • The pharmaceutical industry
  • The textile industry
  • The chemical industry
  • The food industry
  • The landfill leachate industry
If adapted, the process can also be used for micropollutant removal. The ozone fully or partially oxidizes the micropollutants and other substances left in the wastewater, and makes other substances biodegradable. A special bioactive filtration process is then used to degrade the biodegradable substances, any reaction products created through ozonation, and other micropollutants. The latest research has revealed that this kind of filtration boasts better degradation performance than other methods of biological secondary treatment. On top of that, the additional benefits of tertiary filtration can be harnessed (solids removal, tertiary nitrification, phosphorus removal by means of flocculation filtration).

Key Features

  • Space-saving system with low operating costs
  • General improvement in effluent quality (solids, ammonium, phosphorus)
  • Easy to integrate into existing filtration systems
  • Straightforward and reliable automated operation

WABAG Specialty

The combined ozonation/bioactive filter treatment process brings together two technologies that have long been part of WABAG's repertoire. To date, we have incorporated this combined process into more than 50 drinking water treatment plants. Thus, the application of this pioneering combination to wastewater treatment was only a small step for us. WABAG took part in the Micropoll projects in Regensdorf and Lausanne, and has equipped the first of a series of French plants with a process for removing micropollutants. Work on further plants is already underway.


ARA Reinach

37'000 EGW
1'470 m3/h

ARA St. Pourçain (F)

15'000 EW
90 m³/h

ARA Würenlingen

350 m³/d (Deponiesickerwasser)

PACOPUR-SF® (Pulveraktivkohle + Raumfiltration)

PACOPUR-SF® (Powdered Activated Carbon + Deep Bed Filtration)

Removal of micropollutants.

Another way to remove micropollutants is adsorption by powdered activated carbon (PAC). This involves adding the PAC to the secondary treatment effluent and removing it from the wastewater again after a specific contact time. Separation can be achieved in two stages (sedimentation and filtration) or in a single stage (i.e., filtration without additional sedimentation). In both cases, deep bed filtration technology delivers the best performance. The defining features of the single-stage process are that it saves a huge amount of space and cuts costs due to the omission of the sedimentation stage.

Key Features

  • Reliable separation of solids and PAC
  • Huge space savings with the single-stage process
  • General improvement in effluent quality (solids, ammonium, phosphorus)
  • Easy to integrate into existing filtration systems
    Straightforward operation

WABAG Specialty

WABAG has been constructing wastewater filters for all kinds of applications since the 1970s and, in the course of various research projects, has laid the necessary foundations for adapting the filter to this new PACOPUR-SF® application. Our many years of expertise, coupled with the findings from the latest research, make us your first port of call for filter systems for micropollutant removal.

WABAG wastewater filters are being used downstream of the sedimentation stages at various wastewater treatment plants in Germany and in Herisau (Switzerland). A further installation is currently being produced for the Lake Thun treatment plant. There are also plans to use the single-stage process at the Cham Schönau treatment plants with existing filters.


ARA Sissach Ergolz

2014 - 2015

ARA Kloten-Opfikon


ARA Vidy



PACOPUR®-MF (Powdered Activated Carbon + Membrane Filtration).

Removal of micropollutants.

Membrane filtration processes can also be used to capture the PAC. Two appealing solutions are available:

  • Simultaneous dosing of the PAC into the activated sludge on MBR systems (membrane bioreactors). This results in a highly compact plant that is still capable of achieving the generally exceptional effluent quality that you would expect from an MBR. Due to several factors, the rate of PAC consumption is no higher than with tertiary dosing (when the PAC is added to the secondary treatment effluent), making this concept even more attractive.
  • With tertiary PAC dosing, the carbon is separated by means of membrane filtration instead of using deep bed filtration.

Key Features

  • Space-saving process solutions
  • High-quality effluent thanks to membrane filtration (no solids and virtually no microbes)
  • Easy to integrate into existing MBR systems

WABAG Specialty

WABAG is able to cite numerous reference projects as evidence of its expertise in membrane filtration systems for the wastewater industry.

Having carried out extensive pilot tests in Switzerland to investigate how wastewater containing PAC behaves during membrane filtration, WABAG has laid the necessary foundations for dimensioning this combined process and putting it into practice.


ARA Le Locle


ARA Birs

2012 - 2013

CARBOPUR® (Granulierte Aktivkohle)

CARBOPUR® (Granulated Activated Carbon).

Removal of micropollutants.

With this process, the micropollutants are removed through adsorption by granulated activated carbon (instead of PAC). Here, the GAC serves as the filter medium for deep bed filtration. As a result, there is no need for the PAC dosing, adsorption reaction, and PAC removal steps – essentially making this solution very straightforward. On the other hand, the carbon has to be periodically replaced or regenerated.

Key Features

  • Easy to retrofit on existing deep bed filtration systems
  • Space-saving technology (no contact tank)

WABAG Specialty

WABAG has collaborated with universities and research groups on various pilot projects and large-scale tests.


ARA Dübendorf

2014 - 2015

ARA Bülach

2014 - 2015


Sludge Treatment.

WABAG - Schlammbehandlung
WABAG - ANAMMOX – Faulwasseraufbereitung

ANAMMOX – Digester Supernatant Treatment.

Efficient nitrogen removal from digester supernatant.

The separate treatment of the nitrogenous return supernatant from the sludge treatment process constitutes a special application. In this way, the treatment plant's denitrification performance can be boosted while taking the pressure off the biological treatment stage. The nitrogen can be removed from the return supernatant conventionally by using an external denitrification substrate or can be removed by means of the innovative anammox process.

The conventional method of removing the nitrogen separately generates high operating costs because of the need for intensive aeration and the addition of methanol. With the anammox method, the operating conditions are carefully controlled so that the ammonium is only oxidized into nitrite (instead of nitrate). This is then converted into nitrogen – at the same time as ammonium – by special microorganisms. As a result, this process requires 60% less oxygen and no methanol at all.

Key Features

  • Takes the pressure off the biological treatment stage
  • Very low operating costs compared to the methanol method

WABAG Specialty

The FLUOPUR carrier material is used to hold the anammox biomass. This largely prevents the loss of very slow-growing microorganisms in the event of operational disturbances and increases operational stability.





For details of our complete range of technology, please visit the WABAG Group homepage:


sustainable solutions. for a better life.

WABAG Water Technology Ltd
Bürglistrasse 31
P.O. Box
CH-8401 Winterthur

Tel. +41 52 218 14 14 
Fax +41 52 218 14 99


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