COMPAS Comparative Study of Small Wastewater Treatment Technologies

Project title

Comparative study of small wastewater treatment technologies under special operation conditions at BDZ test field in Leipzig

Project initiator

KWB with contract to TU Berlin, Department Urban Water Management (Endowed Chair KWB-Veolia Wasser), Training and Demonstration Centre for Decentralised Sewage Treatment (BDZ), Umweltforschungszentrum Halle Leipzig (UFZ), Kommunale Wasserwerke Leipzig (KWL)

Project volume

198.255 €

Project start



12 months


In rural areas, small wastewater treatment plants (SWWTP) are a cost-efficient solution to sewage disposal issues. In Europe, small WWTPs are defined as plants for treating domestic wastewater up 50 PE. In Germany, about 2.2 million SWWTPs are in operation or are being installed. In France about 10 to 12 million people are served by decentralised systems.

There are many different technical solutions on the market, ranging from artificial wetlands, reed bed filters to activated sludge systems. All systems available on the European market have to meet the EU-Certification EN 12556-3, which regulates a minimum standard of operation reliability and purification limits. Furthermore, additional guidelines have to be considered, depending on national and regional specifications. There is still a lack of information about performance, operation reliability and maintainability of the different types of SWWTP under real operating conditions. These parameters are however, of particular importance to both customers and service providers. To fill this gap, the proposed study will systematically compare and evaluate 12 different treatment systems run simultaneously and under same operating conditions. The study will thus generate detailed information about the performances of different plant models with regard to purification capacity, effluent values, operating expenditures, sludge treatment etc.  


Dr. Bodo Weigert


Financial support: