Prechlorination routinely applied for the treatment of algae-laden raw water has received extensive attention due to its influence on water quality and aquatic microbes. In this study, prechlorination experiments with different doses were conducted in sets of model raw water distribution systems. With the elevated dose of chlorine and prolonged hydraulic retention time (HRT), the ratio of intact algal cells decreased, and the stability of water enhanced. Dissolved organic carbon (DOC) and nitrogen (DON) increased when chlorine dose elevated from 0 to 0.5 mg/L but decreased with elevations from 0.5 to 2.0 mg/L, while UV254 showed a monotonically increasing tendency. DOC, DON and extracellular microcystin-LR increase initially and decrease thereafter with the pro-longed HRT. Notably, the effects of prechlorination on extracellular polymeric substances aggregation behavior on pipe walls and microbial community composition was revealed, providing more profound understanding of the community dynamics in this engineered system. This study helped optimize strategies to improve the stability and efficiency of pretreatment of algae-laden water.

备用水源原水管道较为封闭,原水停留时间过长会导致溶解氧(DO)浓度降低,管道环境由好氧变为缺氧甚至厌氧,从而引起水质恶化.实验室模拟M、N两种不同水源条件在原水管道的备用状态,以DO降至2 mg/L确定停留时间,探究相应的水质变化以及原水的化学稳定性和管壁微生物群落多样性.结果表明,DO在水质较差水源条件下的衰减时间明显短于水质较好的水源.两种水源水都具有严重腐蚀性,出水pH、总碱度和钙硬度均显著升高.M装置进水水质相对较差,微生物存在水平高,对有机物的去除率更高,CODMn和UV254的去除率分别为27.8％和22.9％,而N装置分别为24.6％和21.4％;M装置中的硝化作用更强,NO3--N生成率为23.4％,而N装置为16.2％.两组装置管壁生物膜中的优势菌门基本相同,但丰度较高的菌门差异较大,而丰度较低的菌门差异不明显.较高的NH4+-N浓度有利于增加硝化螺旋菌门的丰度,从而促进硝化作用.良好的水质可以增加管道内的微生物多样性,更有利于管道内生态系统的稳定.

蓝藻水华暴发时原水管道可能混入大量藻细胞,威胁饮用水安全.研究采用BAR模拟管道装置,对比探究105 cell/mL、106 cell/mL两种不同浓度含藻原水在长距离输送过程中的水质变化.以无藻原水作为对照,采用高通量测序研究管壁生物膜群落结构多样性,以探究原水管道中藻类浓度对水质及管壁生物膜的影响.结果表明,两种藻类浓度下原水pH略微上升,溶解氧和浊度逐渐降低,UV254和总磷呈下降趋势,而溶解性有机碳在高藻水中先上升后下降.胞外有机物在低藻水中变化不大,在高藻水中波动上升,而胞内有机物均不断增加.高藻水可能存在藻毒素超标风险.原水中藻类浓度增加有利于管壁生物膜群落多样性的提高,其对管壁生物膜影响不大,优势菌门均为变形菌门和拟杆菌门.

The use of fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) and fluorescence excitation-emission matrix (EEM) systematically provide more comprehensive information on the changes in dissolved organic matter (DOM) composition and characteristic in water treatments. Therefore, this study aims to provide information on the molecular and spectroscopic characteristics of DOM in a full-scale drinking water treatment plant (DWTP) and summarize the effects of different treatment processes on DOM. This study sheds light on the molecular transformation of DOM in conventional treatments and advanced treatments.