固体停留时间对HLB-MR反应器直接回收城市污水中有机物的影响

为优化高负荷生物絮凝-膜反应器（HLB-MR）的工艺参数，提高其资源化城市污水的效能，采用平行对比实验，考察了不同固体停留时间（t_SR）条件下反应器的有机物去除效率、生物絮凝效果、有机物回收效果和膜污染情况。结果表明：在t_SR分别为0.2、0.6、1.0 d时，HLB-MR反应器有机物去除效率均在85%以上，其出水化学需氧量（COD）质量浓度均保持在30 mg/L左右；反应器内的生物絮凝效果随着t_SR的延长而增强，其胶体COD絮凝效率从t_SR为0.2 d时的66%增加到t_SR为1.0 d时的95%，与此同时，有机物的矿化损失率也逐渐增加，从t_SR为0.2 d时的6.9%增加到t_SR为1.0 d时的10.5%，总COD的回收率逐渐降低；反应器内浓缩液的膜污染潜势随着t_SR的延长逐渐缓解，这与较长t_SR条件下反应器内胞外聚合物（EPS）产量较高、生物絮凝效果较好、微细颗粒（0~1 μm）的颗粒浓度较低有关。经过综合对比分析，0.6 d为反应器较优的t_SR参数，在该条件下，胶体COD的絮凝效率高达90%，膜污染程度较轻；总COD的矿化损失率低至7.4%，总COD的回收率（忽略膜清洗时有机物损失）可高达80%以上。

Effects of Solid Retention Time on Organic Matter Recovery Directly from Municipal Wastewater by High Loaded Bioflocculation Membrane Reactor

In order to optimize the process parameter of high loaded bioflocculation-membrane reactor (HLB-MR) and improve its efficiency of recovering organics in municipal wastewater, the organics removal, bioflocculation, organics recovery, and membrane fouling of the reactor were investigated under different solid retention time (t_SR) in parallel. When the HLB-MR operated at t_SR of 0.2, 0.6, and 1.0 d respectively, all the efficiencies of organics removal reached above 85% and the chemical oxygen demands (COD) of permeate were all stable at around 30 mg/L. The bioflocculation effect was enhanced with the extension of t_SR, and the flocculation efficiency of colloid COD increased from 66% when t_SR was 0.2 d to 95% when t_SR was 1.0 d. The mineralization loss rate of organics increased gradually from 6.9% when t_SR was 0.2 d to 10.5% when t_SR was 1.0 d, while the recovery rate of total COD decreased gradually. The membrane fouling potential of the concentrate in the reactor was gradually alleviated with the extension of t_SR, which was related to higher EPS yield, better bioflocculation effect and lower particle fraction of fine particles (0-1 μm) under a longer t_SR in the reactor. Compared with 0.2 d and 1.0 d, 0.6 d was considered to be optimal t_SR of the HLB-MR from a comprehensive perspective. Under this condition, the flocculation efficiency of COD was up to 90%, the membrane fouling was relatively light, the total COD loss rate was as low as 7.4%, and the recovery rate of total COD could be as high as 80% if the loss of organic matter was ignored during the membrane cleaning.