title: Nonoxidative removal of organics in the activated sludge process.
abstract: The activated sludge process is commonly used to treat wastewater by aerobic oxidation of organic pollutants into carbon dioxide and water. However, several nonoxidative mechanisms can also contribute to removal of organics. Sorption onto activated sludge can remove a large fraction of the colloidal and particulate wastewater organics. Intracellular storage of, e.g., polyhydroxyalkanoates (PHA), triacylglycerides (TAG), or wax esters can convert wastewater organics into precursors for high-value products. Recently, several environmental, economic, and technological drivers have stimulated research on nonoxidative removal of organics for wastewater treatment. In this paper, we review these nonoxidative removal mechanisms as well as the existing and emerging process configurations that make use of them for wastewater treatment. Better utilization of nonoxidative processes in activated sludge could reduce the wasteful aerobic oxidation of organic compounds and lead to more resource-efficient wastewater treatment plants.
authors.affiliation: Division of Water Environment Technology, Department of Civil and Environmental Engineering, Chalmers University of Technology , Gothenburg , Sweden.
authors.forename: Oskar
authors.initials: O
authors.lastname: Modin
authors.affiliation: Division of Water Environment Technology, Department of Civil and Environmental Engineering, Chalmers University of Technology , Gothenburg , Sweden.
authors.forename: Frank
authors.initials: F
authors.lastname: Persson
authors.affiliation: Division of Water Environment Technology, Department of Civil and Environmental Engineering, Chalmers University of Technology , Gothenburg , Sweden.
authors.forename: Britt-Marie
authors.initials: BM
authors.lastname: Wilén
authors.affiliation: Department of Chemistry and Molecular Biology, Gothenburg University , Gothenburg , Sweden.
authors.forename: Malte
authors.initials: M
authors.lastname: Hermansson
keywords: Adsorption; DLVO theory; colloids; contact-stabilization; high-rate activated sludge; polyhydroxyalkanoate; triacylglyceride