Cold-adapted sediments and soils as inocula for carbon positive anaerobic wastewater treatment at 15℃
Most attempts to develop anaerobic wastewater technologies for temperate regions use simulated wastewater.They typically overlook the lack of compound complexity and the ubiquity of sulphate in domestic wastewater.The presence of this alternative electron acceptor will invariably reduce the volume of methane and thus be detrimental to the energy balance of the treatment.To investigate the feasibility of energy positive wastewater treatment at challenging HRT and temperature (15℃) one UASB and one AnMBRUASB (UF) reactors started-up with biomass from reactors seeded with soils and sediments from low temperature environments and fed with real municipal wastewater.The reactors were initially operated in batch mode and then continuously at varying HRT.In batch mode COD removal and methane production rates is the rate limiting step (30.8 and 15.82 mgCOD.L-l.day-1 respectively).Both hydrolysis and acidogenesis had fast rates (93.7 and 137.5 mgCOD.L-1.day-1 respectively).The COD removal/methanogenesis limitation was overcome by applying a reduced HRT,continuous feeding regime (OLR ≤0.45 kgCOD.m-3.day-1,HRT ≥0.58 days).Both systems met the UWWTD COD standard with the AnMBR COD removal more robust (79.3±1.3%) than the UASB (63.7±3.4%).The effluent sCOD was polished by the membrane biofilm.The methane production rates were higher in the AnMBR than in the UASB (0.389±0.06 and 0.205±0.04 mmols.HRT-1,COD∶CH4∶35.5±18.4% and 20.9± 10.5% respectively).The difference is attributed to the higher methanogenic cell abundance in the AnMBR (1.9 times more than UASB).Low methane conversion is credited to the high influent SO4 (134.6±9.3 mg.L-1) from which both setups lost 36.1 ±2.9% of COD.The UASB setup was energy positive (0.12 kWh.m3) whilst the addition of the membrane renders the treatment energy negative (-0.01 kWh.m-3).Both setups have a high potential in converting the wastewater treatment process to an important energy production unit (≥0.7 kWH.m-3) under SO42-free wastewater feeding regimes.
Low temperature Wastewater treatment Methanogenesis Energy positive
E.Petropoulos T.P.Curtis J.Dolfing
School of Civil Engineering and Geosciences, Newcastle University, Newcastle NE17RU, England, UK
国际会议
The 15th IWA World Conference on Anaerobic Digestion( 第15届IWA世界厌氧大会)
北京
英文
575-579
2017-10-17（万方平台首次上网日期，不代表论文的发表时间）