The Fate of Organic Pollutants in Wastewater and Sludge Treatment: Significant Processes and Impact of Compound Properties

The fate of organic pollutants during wastewater and sludge treatment is determined by three main processes: gas exchange, sorption to suspended solids, and biodegradation. The influence of these processes differs strongly depending on the physicochemical properties of the individual compound and the particular treatment stage. For the assessment of the fate of trace pollutants in wastewater treatment, the impact of these processes must be evaluated. An acceptable removal in mechanical-biological wastewater treatment is achieved for hydrophilic compounds if they are rapidly degradable under aerobic conditions. Substances with lipophilic or amphiphilic properties should be degradable under aerobic and anaerobic conditions in order to prevent accumulation in digested sewage sludges. This article presents recent and current investigations at EAWAG which deal with the fate of selected organic substances in municipal wastewater and sludge treatment