Removal of chlorinated organic compounds during wastewater treatment: achievements and limits

A large number of chlorinated contaminants are found in wastewater, originating from domestic and industrial sources and from runoff captured by sewers. The presence of some of these contaminants, such as the pharmaceutical diclofenac, has recently been documented, whereas the presence of other contaminants, such as polychlorinated biphenyls, has been known for many years. This mini-review discusses the current state of knowledge regarding the degradation and outflow of chlorinated contaminants from municipal wastewater treatment plants (WWTPs) and the known physiologies of bacteria capable of degrading these contaminants, and summarizes current knowledge gaps as a way to focus future research efforts.