Massé Anthony, Spérandio Mathieu, Cabassud Corinne
INSA, Laboratory of Chemical and Environmental Engineering, LIPE, 135 avenue de Rangueil, 31077 Toulouse cedex 4, France.
Water Res. 2006 Jul;40(12):2405-15. doi: 10.1016/j.watres.2006.04.015. Epub 2006 Jun 8.
This work aims to compare biomass structure and performance of a submerged membrane bioreactor (SMBR) and an activated sludge process (ASP) treating the same domestic wastewater. The influence of the separation technique (membrane filtration or settling) and operation at high sludge-retention time (SRT) were investigated. Over the entire range of SRT (10-110 days), the SMBR achieved very good organic removal efficiencies, ranging from 90.8+/-0.2% to 94.2+/-1.6% based on total COD (TCOD), whereas those of ASP were between 87.4+/-1.8% and 90.3+/-0.8%. The contribution of the membrane in the increase in performance was due to total suspended solid retention and also partly due to retention of proteins and polysaccharides of the sludge supernatant. No significant difference in excess sludge production was observed between the two processes operated at the same SRT, but sludge production in SMBR decreased from 0.31 to 0.13 g(VSS)g(COD)(-1) as SRT increased from 9 to 110 days. The difference in sludge characteristics and performance was especially pronounced as SRT increased, resulting in deterioration of sludge settleability and effluent quality of the ASP (filamentous bacteria, increase of protein and polysaccharide release). Membrane filtration induced accumulation of soluble and colloidal proteins and polysaccharides which were progressively degraded in the supernatant as the SRT increased. At similar SRT, no significant difference was observed in the amount of extractable exocellular polymeric substances (bound EPS) from ASP and SMBR sludge. However as the SRT increased, the total specific amount of bound EPS in flocs decreased and the ratio proteins/polysaccharides also decreased. Concomitantly, laser diffraction analysis, microscopic observations, turbidity and DSVI measurement showed that the SRT increase induced significant modifications in sludge morphology in SMBR: decrease in floc size, densification of aggregates, and development of non-flocculating organisms.
本研究旨在比较处理相同生活污水的浸没式膜生物反应器（SMBR）和活性污泥法（ASP）的生物量结构及性能。研究了分离技术（膜过滤或沉淀）以及在高污泥龄（SRT）下运行的影响。在整个SRT范围（10 - 110天）内，SMBR实现了非常好的有机物去除效率，基于总化学需氧量（TCOD），去除率范围为90.8±0.2%至94.2±1.6%，而ASP的去除率在87.4±1.8%至90.3±0.8%之间。膜对性能提升的贡献归因于总悬浮固体的截留，也部分归因于污泥上清液中蛋白质和多糖的截留。在相同SRT下运行的两个工艺之间，未观察到剩余污泥产量有显著差异，但随着SRT从9天增加到110天，SMBR中的污泥产量从0.31降至0.13 g（挥发性悬浮固体）g（化学需氧量）⁻¹。随着SRT增加，污泥特性和性能的差异尤为明显，导致ASP的污泥沉降性能和出水水质恶化（丝状菌、蛋白质和多糖释放增加）。膜过滤导致可溶性和胶体蛋白质及多糖积累，随着SRT增加，这些物质在上清液中逐渐降解。在相似的SRT下，从ASP和SMBR污泥中提取的胞外聚合物（结合型胞外聚合物）量未观察到显著差异。然而，随着SRT增加，絮体中结合型胞外聚合物的总比量减少，蛋白质/多糖的比例也降低。同时，激光衍射分析、显微镜观察、浊度和污泥容积指数测量表明，SRT增加导致SMBR中污泥形态发生显著变化：絮体尺寸减小、聚集体致密化以及非絮凝性生物体的生长。
