domestic waste water - KWZI

Small water treatment plants

Our small water treatment plants are suitable for the treatment of domestic waste water with a daily load of more than 20 to 1,000 IU. The operation of these installations can be divided into different purification steps


In this step, the waste water is prepared to be offered to the water treatment plant. Depending on the quality of the influent, it can be a grease separator or a mechanical filter.


The domestic waste water ends up in the pre-settlement via the inlet of the WWTP, where it is liquefied. Primary sludge formation also takes place here and all non-water-soluble substances are collected. At the same time, the return sludge from the post-settling (secondary sludge) is also stored here. After this physical pre-treatment, the waste water is discharged to the bioreactor by gravity or via a pump.

Anoxic reactor and pump buffer:

This step ensures optimum removal of the nitrogen present in the waste water. For this purpose, the treated water is re-added to the anoxic reactor by means of a circulator , so that the oxygen-free waste water comes into contact with the waste water rich in nitrates, so that denitrification can take place under ideal conditions.

The incorporated pump buffer ensures that any peak flow rates are smoothed out . The built-in speed limiter allows the water to flow gravitationally to the bioreactor at a low speed .

Bioreactor & Aeration:

The carrier material is located in the bioreactor: granulates based on the fluidized and floating bed principle. The bacteria that purify the water will attach themselves to it.

Contaminants are absorbed as food and converted into ecologically acceptable substances. The micro-perforated EPDM membrane aerators, which are located at the bottom of the bioreactor and can be removed very easily, ensure that oxygen is supplied to the bioreactor at a time interval, causing the carrier material to move into free vortex movements and at the same time also oxygenate the biology .

Settlement & airlift:

The purified water reaches the final sedimentation via the (perforated) overflow, which prevents the carrier material from leaving the bioreactor under hydraulic load at all times. In this chamber the remaining suspended matter settles and the purified water is subsequently returned to nature. By means of a sludge return facility, the settled substances are transported to the pre-settling.

Tertiary purification:

Depending on the required effluent quality, the tertiary treatment can consist of filtration (sand, micro or ultrafiltration), adsorption with activated carbon and/or UV filtration. The effluent can obtain such a quality that it can be reused.

Important benefits:

  • Very compact concept: the land intake is extremely limited;
  • High degree of flexibility, which makes the installation extremely suitable for absorbing peak loads and can be expanded to handle a larger organic load by simply adding carrier material. This without additional structural work and without the compressor necessarily having to be replaced by a more powerful and more expensive one.
  • The carrier material has an increase in surface area of 450 m 2 /m 3 , which means that the WWTP can be dimensioned as compactly as possible.
  • Very user-friendly thanks to the control that is easy to operate by the user and the installer and that allows minor faults to be rectified immediately by the user by means of a test button. This control can be provided with a telemetry system. This GSM module is able to recognize the type of error (compressor failure, airlift failure, pump sump failure, etc.) and send multiple SMS messages (different error messages) to pre-programmed GSM numbers.
  • Most maintenance-friendly installation thanks to the self-cleaning nature of the carrier material, which means that it never has to be removed from the bioreactor.
  • Available in different concrete qualities and traffic load classes.
  • The water purification installation is delivered in accordance with the code of good practice. Commissioning of the KWZI is carried out by a technician trained by ecobeton water technologies.
  • When a comprehensive maintenance contract is taken out, all parts are replaced free of charge during the term, so that the guarantees on the proper functioning and purification performance of the water treatment plant are permanently guaranteed.