Full-scale experience with enhanced biological phosphorus removal (EBPR) in cold climates

This investigation includes three years of full-scale experiences at the fi rst EBPR plant in Norway, Groos WWTP in Grimstad. The main focus was on low temperature performance (below 7 degrees C) and the effect of wastewater c haracteristics (COD). The treatment efficiency was not affected by low temp erature; 0.35 mg/l phosphorus in the effluent during 1998 (94 % removal). G OD-levels, however, did affect the process. The results from the study are used as a basis for retrofitting plants that removes phosphorus by chemical precipitation. Results from experiments at a partly retrofitted plant are also presented.