Master’s thesis proposal – Anoxic degradation of organic matter in wastewater


Activated sludge processes are used in wastewater treatment plants for degradation of organic matter and removal of nitrogen compounds from the wastewater. Often activated sludge tanks first consist of an anoxic zone, which removes some organics and reduces nitrate (denitrification). This is followed by an aerobic zone where the remaining organics are degraded. Aerating activated sludge tanks is very energy-consuming and it is desirable to minimize the aeration requirement at treatment plants.


The aim of this Master’s thesis project is to investigate organics removal in denitrifying activated sludge tanks (i.e. no aeration). We will investigate how the nitrate load fed to the tank affects the capacity of the activated sludge to degrade and adsorb organic compound in the influent wastewater.


The theoretical part of this work is to acquire information about organics- and nitrate loads at wastewater treatment plant and then calculate the amount of organics that theoretically could be removed from the influent wastewater using only denitrifying activated sludge.

The practical part of this work is to operate a laboratory-scale activated sludge system and investigate how nitrate loadings affect the capacity of the activated sludge to degrade and adsorb organic compounds in the influent wastewater.

The work will be carried out at Chalmers University of Technology in Gothenburg.


Autumn 2017


Oskar Modin, associate professor, Chalmers,
David Gustavsson, research leader, Sweden Water Research,