Grey water treatment concept integrating water and carbon recovery and removal of micropollutants

A total treatment concept was developed for grey water from 32 houses in Sneek, The Netherlands. A thorough characterization of COD, nutrients, metals, micropollutants and anions was carried out. Four biological treatment systems were tested: aerobic, anaerobic, combined anaerobic + aerobic and a bioflocculation system. Micropollutants were measured in grey water and effluent from three biological treatment systems. The best performing biological treatment system, the aerobic one showed the highest COD and micropollutant removal at a low sludge yield. The bioflocculation system could concentrate 70% of the COD of grey water into a concentrated stream. Advanced treatment with ozone and activated carbon showed to be effective to remove all micropollutants below limits of quantification. A total treatment system is proposed based on the pre-treatment with a bio-flocculation system, aerobic post-treatment and ozonation as a disinfection and micropollutant removal step.