Phosphorus removal in a membrane-assisted BNR process with focus on evolutions of PAOs and DPAOs.
A bench-scale UCT (University of Cape Town)-type membrane bioreactor (UCT-MBR) fed with low-strength synthetic wastewater was operated to investigate phosphorus removal with reference to poly-phosphate accumulating organisms (PAOs) and denitrifying poly-phosphate accumulating organisms (DPAOs). A series of kinetic assays of PAOs and DPAOs were also conducted to analyze the metabolic activities of PAOs and DPAOs. Results showed that 93% of chemical oxygen demand (COD) and 77% of total nitrogen could be removed at 0.08 kgCOD kg(-1) MLSS d(-1) and 0.015 kgN kg(-1) MLSS d(-1) loading (MLSS: mixed liquor suspended solids). Removal efficiencies of total phosphorus increased during the experimental phase, with an ultimate removal efficiency of 96.1%. Kano and Kaer increased from 1.95 and 6.29 mgPO4(3-)-P g(-1) MLSS h(-1) to 5.47 and 11.13 mgPO4(3-)-P g(-1) MLSS h(-1) for DPAOs and PAOs respectively, with the increased ratio of DPAOs to PAOs from 31 to 49% implying DPAO metabolic activity increased faster than that of PAOs during the DPAO accumulation phase. Pano-uptake increased by 6.6 mg L(-1) and the ratio of PTano-uptake to PTupt increased from 58.97 to 91.62%. The ratio of DPAOs to PAOs tended to stabilize at around 50% over time.
College of Architecture and Civil Engineering, Beijing University of Technology, 100 Ping Le Yuan, Chao Yang District, Beijing 100124, China E-mail: zhaozhaomembrane@yahoo.cn; W-Z-Z@163.com.
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Wang
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Wang
D019149:Bioreactors; D058440:Denitrification; D008567:Membranes, Artificial; D010758:Phosphorus / Q000378:metabolism*; D012722:Sewage; D014874:Water Pollutants, Chemical / Q000378:metabolism*
D008567:Membranes, Artificial; D012722:Sewage; D014874:Water Pollutants, Chemical; D010758:Phosphorus