Towards energy neutrality of wastewater treatment plants via deammonification process

Abstract

Energy neutrality of wastewater treatment plants is possible with constant and consistent optimization and implementation of new technologies. In recent years new process called deammonification has been discovered and implemented in treatment of side streams rich in nitrogen. With its implementation on wastewater treatment plants it is possible to remove nearly all nitrogen from side stream (even 30% of overall nitrogen load) in less energy consuming way. Additionally, thanks to lower nitrogen load to main stream reactors it is possible to optimize them to further lower energy consumption. This article presents simulation studies of deammonification implementation and main stream reactor optimization in case of medium Polish WWTP (115 000 p.e.). With removal of 20% of nitrogen in side stream via deammonification and subsequent main line optimization it is possible to save 5000 euro/year by lowering sludge retention time, oxygen concentration in main stream reactors. When additional COD is precipitated in primary clarifiers with iron coagulants, 55 000 euro/year can be saved in case of energy costs which states for most of the energy costs. However, when coagulant and disposal costs are included savings are on the level of 25 000 euro/year.