Nonoxidative removal of organics in the activated sludge process
Journal article, 2016
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.
chemical oxygen-demand
particle-size
different operational modes
mixed
biological phosphorus removal
poly-beta-hydroxybutyrate
distribution
high-rate activated sludge
DLVO theory
polyhydroxyalkanoate
waste-water treatment
extracellular polymeric substances
triacylglyceride
colloids
contact-stabilization
polyhydroxyalkanoate pha production
in-situ transesterification
microbial cultures
Adsorption