重力出流式膜生物反应器的膜通量及膜污染控制研究

采用新型的重力出流式膜生物反应器(MBR)处理生活污水和垃圾渗滤液,考察了其在长期运行过程中膜通量的变化规律及其影响因素.结果表明,该MBR能够在较低液位水头(8.5～15.0 kPa)的作用下连续出水,并获得较高的膜通量.处理生活污水时,平均膜通量为11.2 L·(m²·h)^-1;处理垃圾渗滤液时,平均膜通量为6.4 L·(m²·h)^-1.研究发现,污泥浓度对膜通量影响大小与曝气强度有关.当曝气强度小于400 m³·(m²·h)^-1时,膜通量随着污泥浓度的升高显著下降;当曝气强度大于400 m³·(m²·h)^-1时,膜通量几乎不受污泥浓度和曝气强度的影响.对膜的化学清洗试验表明,NaOH+NaClO溶液清洗效果最佳,膜通量可恢复至初始通量的85%以上.进一步研究表明,混合液中高浓度的溶解性胞外聚合物是MBR处理垃圾渗滤液时膜通量较低的主要原因.

Permeate Flux and Membrane Fouling Controlling of a Membrane Bioreactor with Gravity Flow to Treat Domestic Sewage and Landfill Leachate

A novel membrane bioreactor(MBR) with gravity flow was applied to treat domestic sewage and landfill leachate.The variation of permeate flux and its impact factors were studied.The long-term test showed that the average permeate flux of this MBR could be 11.2L·(m²·h)^-1 under the pressure of 8.5 kPa for treating domestic sewage while 6.4L·(m²·h)^-1 and 15.0 kPa,respectively,for landfill leachate.The permeate flux increased with increase of aeration density and decrease of activated sludge concentration when aeration density was less than 400m³·(m²·h)^-1.While activated sludge concentration and aeration density had hardly impact on the permeate flux when aeration density was more than 400m³·(m²·h)^-1.The performances of several different cleaning solutions were tested and the results showed that NaOH-NaClO solution had the best cleaning efficiency.The permeate flux can recovered over 85% of the initial flux.A very high concentration of soluble extracellular polymeric substances(soluble EPS) existed in landfill leachate compared with domestic sewage,which was the main cause leading to a lower permeate flux when treating landfill leachate.