Biological nutrient removal in a submerged membrane bioreactor.

摘要

The thesis presents an investigation on biological nutrient removal (BNR) in membrane bioreactors (MBRs) for municipal wastewater treatment. Two bench-scale bioreactors (118 Litres) were designed, constructed and operated for 92 days, at solid retention time (SRT) of 15 to 20 days, hydraulic retention times (HRT) of 8, 6, and 4 hours using two bioreactor configurations, in parallel to Gold Bar Wastewater Treatment BNR system.; Below detection limit values for fecal coliforms, BOD5 and TSS were consistently observed in permeate. Also, 94% of COD, 99.8% of NH 3-N and over 72% of TN were removed. In addition, 92.3% of TP reduction, averaged 0.63 mg/L of TP in MBR2 permeate, at a HRT of 6 hours was achieved. The overall average TP and nitrogen reductions were lower than expected due to unstable conditions and excessive dissolved oxygen recycles. High membrane flux (30 L/m2 h) and the membrane integrity were maintained during the 92 day period with a permeate turbidity of 0.117 NTU.