The impact of process variables on the removal of PBDEs and NPEOs during simulated activated sludge treatment

Abstract

Sewage effluent is known to be a major source of endocrine disrupting compounds entering the aquatic environment. More efficient wastewater treatment could reduce the environmental load but, in order to achieve this factors determining compound behaviour must be understood. The knowledge of compound fate is becoming increasingly important for risk assessments and to allow modifications to wastewater treatment works to facilitate treatment of these compounds. This work illustrates that the removal of some endocrine disrupting compounds from sewage treatment works effluent is dependent on parameters such as sludge age, influent concentrations, concentrations of co-metabolites and hydraulic retention time as well as physico-chemical compound properties. From this research it is apparent that the principle environmental risk of plybrominated diphenyl ether contamination after wastewater treatment is via sludge disposal routes. Treatment of wastewater containing nonylphenol polyethoxylate surfactants poses environmental risks via two routes, some nonylphenolic compounds may pass through into receiving waters and degradation products such as nonylphenol and short chain ethoxylate compounds will enter the environment via sludge disposal. 1