金属膜生物反应器处理生活污水膜污染的影响因素

Factors Influencing Membrane Fouling of Metal Membrane Bioreactor in Treating Domestic Sewage

采用浸没式平板金属膜生物反应器处理模拟生活污水,考察好氧与缺氧/好氧(anoxic/oxic,A/O)2种运行模式下ρ(MLSS)和污泥粒径分布对膜过滤性能的影响及膜过滤阻力的组成.结果表明,对于好氧膜生物反应器,存在一个能获得良好膜过滤性能的ρ(MLSS)范围;好氧模式下膜过滤阻力主要为滤饼层阻力,且滤饼层能通过在线药洗或机械清洗较好地去除,系统在膜通量为0.80～1.00 m3/(m2.d)下未进行离线药洗连续运行115 d.A/O模式下膜过滤阻力主要为内部阻力;A/O循环导致污泥破碎解体,产生大量微小粒子,在膜孔内形成吸附和堵塞,使膜过滤性能急剧下降,为维持系统运行,A/O阶段将膜通量从1.00 m3/(m2.d)降至0.50 m3/(m2.d),并进行了15次膜清洗.

A submerged fiat metal membrane bioreactor （MBR） was used to treat synthetic domestic sewage. The experiment was performed under two operational modes of aerobic and A/O processing. The influence on membrane filterability by mixed liquor suspended solid （MISS） mass concentration and particle size distribution of sludge was investigated. Composition of membrane resistance under different operating models was also investigated. The results showed that an optimal MISS mass concentration range existed for corresponding good membrane filterability in aerobic MBR. Cake resistance was found to be the main filtration resistance under aerobic processing. Cake fouling could be alleviated effectively by on-line chemical washing or mechanical cleaning. The system ran stably for 115 days at a permeate flux of 0.80-1.00 m^3/（m^2·d） without off-line cleaning. Internal resistance was found to be the main filtration resistance under A/O processing. The internal circulation of mixed liquor between anoxie and aeration tank caused the destruction of activated sludge floes, and then led to large amounts of small particles, which absorbed in or blocked membrane pores and caused worse membrane filterability. Membrane flux was reduced from 1.00m^3 /（m^2·d） to 0.50 m^3 /（m^2·d）, and cleaning was performed 15 times during A/O processing in order to maintain system operation.