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.

polyhydroxyalkanoate pha production




chemical oxygen-demand

high-rate activated sludge

waste-water treatment

in-situ transesterification


extracellular polymeric substances

biological phosphorus removal


microbial cultures

DLVO theory





different operational modes


Oskar Modin

Chalmers, Civil and Environmental Engineering, Water Environment Technology

Frank Persson

Chalmers, Civil and Environmental Engineering, Water Environment Technology

Britt-Marie Wilen

Chalmers, Civil and Environmental Engineering, Water Environment Technology

Malte Hermansson

University of Gothenburg

Critical Reviews in Environmental Science and Technology

1064-3389 (ISSN)

Vol. 46 7 635-672

Biosorption in the Activated Sludge Process: Mechanisms, Kinetics, and Implications for Process Design

Formas, 2013-01-01 -- 2017-12-31.

Driving Forces

Sustainable development

Subject Categories

Water Engineering

Environmental Sciences

Areas of Advance




More information

Latest update

2/9/2020 2