Proceedings

Biological phosphorous removal (Bio-P) in wastewater treatment plants (WWTP) is apart from chemical precipitation with iron salts one possibility to reduce excess phosphorous in the treated effluent. This field study investigates the enhanced biological phosphorous removal (EBPR) with the use of an improved anoxic-anaerobic selector within a cyclic activated sludge process (C-TECH™). The study was conducted at the Großarl municipal WWTP in the Alpine region of Salzburg and lasted over two years. The results show that with the improved anoxic-anaerobic selector the Bio-P removal could be further increased by over 30% achieving less than 0.3 mg/l total P without any further chemical precipitation. Furthermore, beginning granulation of macrofloc sludge could be measured. The overall plant performance for the other parameters COD, BOD, TSS, NH4-N and T-N at mean values of < 35 mg/l, < 5 mg/l, < 5 mg/l, < 2 mg/l and < 7 mg/l did not change throughout the field test and has been kept on low range, respectively.