Better effluent quality with the fourth wastewater treatment stage at Aachen-Soers

The Eifel-Rur Water Association operates the largest sewage treatment plant on the river Wurm, with the Aachen-Soers wastewater treatment plant having a load of 458,000 population equivalents (PE). It has a dry weather flow of 6,480 m3/h (41 millions of gallons per day, MGD) and a peak wet weather flow of 10,757 m3/h (68.2 MGD), which are treated in the plant and discharged into the receiving watercourse Wurm. In search for the best wastewater treatment process in terms of removal of microbiological contaminants and the abatement of bromate discharge, RWTH Aachen University, along with the other environmental institutions, launched a research project and partnered with Xylem to test the effects of wastewater ozonation on water quality and its ecosystem. The Wedeco ozone systems, Lowara cooling water pumps and WTW multi-parameter online measurement devices were installed. The Wedeco ozone system has demonstrated an astounding performance in three aspects: 1) Elimination of 1 to 3 logs of E. coli, Enterococci and its antibiotic- resistant variants; 2) Reduction and partial elimination of eco- toxicity; and 3) Ensuring bromate level in the effluent is far below the permitted environment quality standards or UQN value.