Effect of anoxic decay process on simultaneous nitrification denitrification in a membrane bioreactor operated without an anoxic tank.
This study was focused on evaluating the role and the effect of anoxic decay on the extent of simultaneous nitrification-denitrification (SNdN) process sustained in a single membrane bioreactor. The membrane bioreactor was fed with relatively strong domestic sewage and operated at steady state at a sludge age of 36 days at a corresponding suspended solids level maintained in the range of 17,500-21,000 mg/L. The SNdN could be sustained due to diffusion limitation of oxygen into the flocs. The evaluation identified an MLSS threshold level of around 17,000-18,000 mg/L below which nitrogen removal was essentially controlled by denitrification and above, the rate limiting mechanism shifted to nitrification maintaining total nitrogen removal efficiency of 85-95% for a typical domestic sewage. The contribution of anoxic decay process to the overall denitrification potential was evaluated as 60%, substantially higher than the remaining 40% associated with the anoxic growth during the SNdN process.
MWH UK Ltd., Dubai, United Arab Emirates. murat.sarioglu@uk.mwhglobal.com
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Sarioglu
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Insel
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Artan
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Orhon
D001673:Biodegradation, Environmental; D018533:Biomass; D019149:Bioreactors; D004058:Diffusion; D004867:Equipment Design; D000860:Hypoxia; D007700:Kinetics; D009573:Nitrites / Q000737:chemistry*; D009584:Nitrogen / Q000302:isolation & purification*; D010100:Oxygen / Q000032:analysis; D012037:Refuse Disposal / Q000379:methods*; D012722:Sewage; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification
D009573:Nitrites; D012722:Sewage; D009584:Nitrogen; D010100:Oxygen