蓝藻胞外聚合物对供水管网水质的影响

针对游离态蓝藻胞外聚合物（EPS）在常规水处理工艺中不易去除、残留蓝藻EPS极易进入供水管网的特性，研究了蓝藻EPS对供水管网水质变化及生物稳定性的影响.针对管道使用时限分析了不同管道内部产生附膜条件下，蓝藻EPS对供水管网中余氯、浑浊度、生物稳定性、有机组分等主要水质指标变化规律的影响.结果表明，蓝藻EPS加快了管网余氯衰减速度，导致管网水质浑浊度在12~24h后即超出生活饮用水卫生标准上限，并使管网水质生物稳定性降低，BDOC在72h内增加37.2~39.5%，AOC增加365~393%，总活菌数升高18~20倍.阐明了蓝藻水华爆发时期净水厂出厂水残留蓝藻EPS在管网余氯存在前提下，仍然能够作为微生物营养基质和代谢能量，而促进管道内细菌生长繁殖，增加微生物代谢活性，刺激微生物胞外有机组分分泌释放，导致管网水质二次污染.

Influence of cyanobacterial extracellular polymeric substances on the water quality in water supply distribution system

Aiming at the characteristics of free cyanobacterial extracellular polymeric substances (EPS) that are difficult to be removed in conventional water treatment processes, and the residual cyanobacterial EPS are easy to enter the water supply distribution system, the influence of cyanobacterial extracellular polymeric substances (EPS) on the water quality and biological stability of water supply distribution system was studied in this paper. The influence of cyanobacterial EPS on the variation of water quality indices, such as residual chlorine, turbidity, biological stability, organic components, and so on, were mainly analyzed under the different membrane attachment internal pipe condition caused by the service time. Results showed that the cyanobacterial EPS accelerated the decay rate of residual chlorine in the pipeline, led to the turbidity exceeding the upper limit of drinking water standard after 12~24h, reduced the biological stability of the pipeline water, increased BDOC by 37.2~39.5%, increased AOC by 365~393%, and increased the total viable bacteria by 18~20 times in 72 hours. It was clarified that the residual cyanobacterial EPS in the effluent of drinking water treatment plant could still serve as a microbial nutrient substrate and metabolic energy under the premise of residual chlorine in the pipe network during cyanobacteria bloom period, and this promoted the growth and reproduction of bacteria within pipeline, increased the metabolic activity of microorganisms, and stimulated the secretion and release of extracellular organic components of microorganisms, resulting in secondary pollution of the water quality.