Etablering av biologisk fosforavskiljning i mindre reningsverk / Establishment of enhanced biological phosphorus removal in smaller wastewater treatment plants
Enhanced biological phosphorus removal (EBPR) of municipal wastewater is not a common treatment method in Sweden. An explanation could be insufficient knowledge about the EBPR process. This article aims to increase the knowledge by describing how to establish and evaluate enhanced phosphorus removal in smaller wastewater treatment plants. The phosphate accumulating organisms, PAO, demand an alternately anaerobic and aerobic/anoxic environment and a carbon source in the state of volatile fatty acids (VFA). A sufficient anaerobic retention time is needed, nitrate recirculation to the anaerobic zone should be minimized and too much aeration and secondary phosphorus release should be avoided. Measurements of phosphorus content in biological sludge and phosphorus release tests can be used to evaluate the EBPR process. Smålandsstenar Wastewater Treatment Plant in southern Sweden is described as an example of a plant where an establishment of EBPR has been made.