城市污水处理厂二级出水具有水质水量稳定、集中、供给可靠等特点。污水回用不仅可以填补城市缺水的巨大缺口，缓解水资源紧缺问题，同时可以减少污水排放量，实现经济效益与环境效益的统一。二级出水经深度处理再生利用过程中，消毒工艺有着至关重要的作用，但化学消毒会产生多种具有危害性的消毒副产物(如亚硝胺类消毒副产物)。近些年研究发现，相比卤代消毒副产物(如卤乙酸等)，亚硝胺类消毒副产物所具有的致癌特性使人类健康面临更大的威胁。水体中常见的亚硝胺物质有N-亚硝基二J胺(N-nitrosodimethylamine，NDMA)、N-亚硝基二乙胺(N-nitrosodiethylamine，NDEA)、N-亚硝基甲乙胺(N-nitrosomethylethylamine，NMEA)、N-亚硝基二正丙胺(N-nitrosodipropylamine，NDPA)、N-亚硝基二正丁胺(N-nitrosodibutylamine，NDBA)、N-亚硝基吗啉(N-nitrosomorpholine，NMOR)、N-亚硝基吡咯烷(N-nitrosopyrrolidine，NPYR)、N-亚硝基哌啶(N-nitrosopiperidine，NPIP)和N-亚硝基二苯胺(N-nitrosodiphenylamine，NDPhA)9种。
相较于自然水体，污水厂二级出水存在更多的亚硝胺类物质的前体物，因而会产生更多的亚硝胺类消毒副产物。臭氧氧化通常应用于污水深度处理中，作为混凝、活性炭吸附的前处理工艺，可有效提高后续工艺的处理效率，同时可有效去除水体中的微量污染物并具有杀菌作用。但有研究发现，臭氧在去除有机物和杀菌的过程中，会使水体中亚硝胺前体物转化为NDMA，从而导致NDMA含量的增加。然而，臭氧氧化与其他工艺联用(如臭氧生物活性炭工艺)也可有效降低亚硝胺类消毒副产物生成势，对其前体物去除率可达90%。因此，臭氧氧化工艺也可作为保障再生水水质安全的一个重要环节。
设计准则：
1) 执行国度环境维护的各项规则，确保经处置后污水水质到达国度及建立单位文件要求的排放规范；
2)本着技术先进合理，工艺运转波动、牢靠，操作管理复杂的准绳选择污水处置工艺，使灵敏性、先进性和牢靠性无机地结合起来；
3) 运用成熟的先进工艺技术，同时充沛思索污水水质、水量的冲击负荷对零碎的影响,使处置零碎的波动性较好；
4) 强化除臭和乐音防治措施，防止二次净化；
5) 次要设备国产化，采用目前国际成熟先进技术配备，降低了工程投资和运转费用；
6) 污水处置零碎设计思索操作运转波动与维护管理复杂方便；
7) 严厉执行国度有关设计标准、规范，特别是平安方面的强迫性规则。
In order to effectively solve the problem of people's domesticwater use and enable people to use drinking water nearby, 11 newcentralized water supply pools were completed in Xinqiao communityof Tuxiang Town, Fengjie County, Chongqing.
It is understood that the total investment of 11 centralizedwater supply pools built in this town is more than 2 million yuan,and the total volume of 11 centralized water supply pools is about6,000 square meters. It can not only solve the perennial waterproblem of more than 600 households and more than 2450 people inthis village, but also solve the water storage and water useproblem of the surrounding traditional crops.
"At present, 11 centralized water supply pools in our communityhave been fully completed." Fang Fang, a branch of Xin in this town, said that solving the problem of people'sdifficulty in drinking water and water use is the first and mostimportant task in carrying out the work of "getting rid of povertyand tackling difficulties". People's affordability of water andwater is the z-high goal of building a new countryside and the mainreserve force for helping people to get rid of poverty and tackledifficulties.