【作者】 王柯；

【导师】 朱光灿； 蒋岚岚；

【作者基本信息】 东南大学 ， 环境工程（专业学位）， 2020， 硕士

【摘要】 截至2018年,江苏省已基本实现城乡统筹区域供水乡镇全覆盖,传统单级消毒方式无法保障长距离、长水龄输配水条件下镇村管网水质持续稳定,镇村段管网水有可能发生余氯不达标和微生物检出现象,因此需要研究多级消毒技术以进一步保障城乡统筹区域供水管网的水质稳定。本文研究了多级消毒对城乡统筹供水管网水中消毒副产物生成及水质生物稳定性的影响,优化了多级消毒策略以保障镇村供水管网末梢水质生物稳定。针对省域内不同原水、不同处理工艺典型城市城乡供水管网水质进行调研,分析管网水质变化规律,考察多级消毒对管网水质的影响,重点关注多级消毒前后管网水中消毒副产物与水质生物稳定性变化。同时,基于管网数学模型对实际供水管网进行的模拟结果,对多级消毒策略进行优化研究。在冬、夏两季分别对江苏省内三大水系（长江、淮河、太湖）代表性城乡供水管网的水质进行跟踪调研,结果显示,不同流域城市的供水管网水质存在一定差异,总体上以长江水为原水的管网水质优于以太湖水、淮河水为原水的管网水质。三大流域管网水质指标中,浊度均表现出随管线延长而上升的趋势,长江、淮河流域调研管线末段出现余氯不达标和菌落总数检出现象,管网水中三氯甲烷（Trichloromethane,TCM）呈现先上升后稳定再下降的趋势。此外,管网水生物可降解溶解性有机碳（Biodegradative Dissolved Organic Carbon,BDOC）和可同化有机碳（Assimilable Organic Carbon,AOC）均表现出随管线延长而先上升后下降的趋势,沿程含量受原水季节性波动影响较小。对净水厂而言,经过深度处理工艺后出厂水中溶解性有机碳（Dissolved Organic Carbon,DOC）含量明显降低,消毒副产物（Disinfection by-products,DBPs）的生成量减少,表明采用深度处理工艺有助于提升出厂水水质。在采用多级消毒的镇村供水管网中,随着管线延长,管网水中COD_Mn和UV₂₅₄逐渐下降,三卤甲烷（Trihalomethanes,THMs）含量先上升后保持稳定,而卤乙酸（Haloacetic Acids,HAAs）含量则是先上升后下降。多级消毒管线沿程管网水中BDOC和AOC沿程先升高后降低,且管线沿程含量高于出厂水。沿程管网水中微生物检出频率较低,末梢段水中余氯含量满足标准要求,表明多级消毒可以有效保障镇村管网水中余氯浓度,但也存在管网水中消毒副产物增多和水质生物稳定性变差的风险。此外,多级消毒前后管网水中有机物特性发生改变,分子量<1 k Da的小分子有机物占比上升,三维荧光光谱结果显示多级消毒后5个区域荧光强度均下降,以富里酸为代表性有机物的Ⅲ区相对荧光强度下降幅度最大,表明该区域内有较多可以与氯发生反应的活性物质,因此该类有机物对该多级消毒管网水中消毒副产物的生成贡献较大,需要重点控制。使用EPANET2.0软件构建Y镇实际供水管网水力水质模型,调整管道初始海曾-威廉C值进行水力模型校核,控制节点压力模拟值与实测值误差在0.02 MPa以内。基于准确的水力模型进一步构建管网余氯衰减和三卤甲烷生成的水质模型,控制水质监测点模拟值与实测值误差在30%以内。通过模拟多级消毒方案的调整,以保障管网末梢余氯达标和减少三卤甲烷生成为目标,优化多级消毒的点位设置和分级消毒剂投加量,提出适合Y镇供水管网的最佳多级消毒方案。更多还原

【Abstract】 As of 2018,Jiangsu Province has almost achieved the overall coverage of urban and rural regional water supply towns.The traditional single-stage disinfection method cannot guarantee the continuous stability of the water quality of the town and village pipeline network under the conditions of long-distance and long-age water transmission and distribution,the residual chlorine and the appearance of microbiological examination may happened,so it is necessary to study multi-level disinfection technology to further ensure the stability of water of the urban and rural integrated regional water supply network.The goal for this research is the effect of multi-level disinfection on the generation of disinfection by-products and the biological stability of water quality in the urban-rural water distribution network has examined,by optimizing the multi-level disinfection strategy to ensure the biostability of the water quality at the end of the township water supply network.the water quality of urban and rural water supply networks in typical cities with different raw waters and different treatment processes in the province was investigated,the changes in the water quality of the network,investigate the impact of multi-level disinfection on the water quality of the network,and focus on the by-products and water quality biological stability changes was examined.Meanwhile,the multi-level disinfection optimization strategy is studied to simulate the actual water supply network based on the mathematical model of the network.In winter and summer,the water quality of the representative urban and rural water supply network of the three major river systems（Yangtze River,Huaihe River,Taihu Lake）in Jiangsu Province was followed up.The water quality of the pipe network with Yangtze River water as the raw water is better than those of Taihu Lake and Huaihe River.Among the water quality indicators of the three major river basins,the turbidity showed a tendency to increase with the extension of the pipeline.The residual chlorine in the end of the investigation pipelines in the Yangtze and Huaihe river basins did not meet the standard and the total colony inspection showed signs.Trichloromethane in the pipeline network showed a trend of rising at first,then stabilized and then decreased.In addition,the biodegradable dissolved organic carbon（BDOC）and assimitable organic carbon（AOC）of the water in the pipe network both showed a trend of increasing first and then decreasing with the extension of the pipeline.For the water purification plant,the content of dissolved organic carbon（DOC）in the factory water is substantially reduced after the advanced treatment process,and the production of disinfection by-products（DBPs）is reduced,indicating that the use of the advanced treatment process can help improve the quality of the factory water.In the township village water supply pipeline network with multi-stage disinfection,as the pipeline is extended,the COD_Mn and UV₂₅₄ in the pipeline water gradually decreased,the content of trihalomethanes（THMs）rised first and then remained stable,while the haloacetic acid（HAAs）the content increaseed first and then decreased.The BDOC and AOC in the water of the multi-stage disinfection pipeline along the pipeline network increased first and then decreased,and the content along the pipeline is higher than that of factory water.The detection frequency of microorganisms in the water along the pipeline network was low,and the residual chlorine content in the distal section water meets the standard requirements.However,there are also risks of increased disinfection by-products and deterioration of the biostability of the pipe network water.In addition,before and after multi-stage disinfection,the characteristics of organic matter in the pipe network water changed,and the proportion of small molecular organic matter（<1 k Da）increased.The proportion of small-molecule organics（<1 k Da）increased.The results of three-dimensional fluorescence spectroscopy showed that the fluorescence intensity of all five areas decreased after multi-stage disinfection.The relative fluorescence intensity of zoneⅢwith fulvic acid as the representative organic substance decreased the most,indicating that within this area.There are many active substances that can react with chlorine.Namely,this kind of organic matter substantially contributes to the generation of disinfection by-products in the multi-stage disinfection pipe network water,which needs to be controlled.Using EPANET2.0 software to establish the hydraulic water quality model of the actual water supply network in town Y,adjusted the initial Hyzen-William C value of the pipeline to check the hydraulic model,and the error between the simulated value and the measured value of the control node pressure was within 0.02 MPa.Based on accurate hydraulic model,a water quality model of residual chlorine attenuation and trihalomethane generation in the pipe network is further constructed,and the error between the simulated value and the measured value of the water quality monitoring point was controlled within 30%.By simulated the adjustment of multi-stage disinfection schemes,the goal was to ensure that the residual chlorine at the end of the pipe network meets the standard and the formation of trihalomethanes is suppressed.Optimized the location setting of multi-level disinfection and the dosage of graded disinfectant,and put forward the best multi-level disinfection scheme suitable for the water supply network of Y town.更多还原