Biological nitrogen removal with enhanced anoxic phosphate uptake In a sequencing batch membrane bioreactor

摘要

Simultaneous biological phosphorus and nitrogen removal with enhanced anoxic phosphate uptake was investigated in an anaerobic-aerobic-anoxic sequencing batch membrane bioreactor (AOA SBMBR). Its performance was compared with an anaerobic-aerobic (AO) SBMBR. Significant amounts of phosphorus- accumulation organisms (PAOs) capable of denitrification could be accumulated in a single sludge system coexisting with nitrifiers. Obviously anoxic phosphorus uptake had been observed in the AOA SBMBR. Compared to AO SBMBR, the ratio of the anoxic phosphate uptake to the aerobic phosphate uptake capacity was increased from 13% to 26% in AOA SBMBR. The AOA SBMBR showed stable organic carbon and nutrient removal performance. The average removal efficiencies of COD, total nitrogen, and phosphorus were about 96.2%, 83.8% and 82.7%, respectively. Furthermore, compared with AO sludge, the Puptake/Ndepletion ratio of AOA sludge increased from 0.24 g TP/g NO3"-N to 0.55 g TP/g NO3"-N in the anoxic phase during phosphate uptake batch test. This indicated that by introducing an anoxic phase into the AO SBMBR, the ability of denitrifying phosphate uptake of the sludge was increased during the anoxic process. It was found that the cell proliferation rate under AOA operation condition was only 68.4% of that under AO condition and the larger particle size had been observed under AOA condition.