除了水的回收和再利用项目，间接饮用水的再利用 废水在过去几十年中一直存在，随着时间的推移，未来可能会增加 上游污水处理厂（WWTP）将水排入河流或湖泊，作为 下游饮用水供应。间接饮用水再利用可定义为 饮用水处理厂（DWTP），包含废水的点源排放；化粪池 与河流相邻也可能改变地表水的质量。干旱与河道内竞争 需求可能导致处理后的废水对环境的贡献小于10%至>50% 小溪在流动。人们的注意力集中在药物和内分泌干扰物上，但 如果需要氯消毒，污水处理厂也是消毒副产物（DBP）的来源 实践，和DBP先驱。 生物废水处理有两种一般形式: 暂停生长 （biofloc）系统（如活性污泥）和附着生长（生物膜）系统（如滴滤 过滤器）。根据运行条件，两者都可以部分或完全运行 硝化过程。硝化作用水平的增加会降低氨的浓度 和有机氮（氨基）化合物。硝化作用转化氨和有机物 氮转化为硝酸盐。缺氧条件下的悬浮生长系统可以反硝化（转化 硝酸盐主要转化为氮气）。 经处理的废水（废水有机物[EfOM]）已被证明是污染源 多种DBP（三卤甲烷[THM]、卤乙酸[HAAs]的前体， 卤代乙腈[HANs]和亚硝胺）。本研究的目的是评估 处理后的废水对饮用水中DBP形成的贡献。 作者对美国大约20个污水处理厂进行了全面调查（年） 西部、西南部、山区、中南部、中西部和东北部）。WWTPs是 采用了一系列处理工艺（氧化沟、曝气泻湖、滴流）的样品 过滤器、活性污泥、硝化/反硝化、土壤含水层处理[SAT]，粉状 和/或颗粒活性炭[PAC，GAC]，膜生物反应器[MBR]，反渗透 [RO]或各种组合）。对于大多数研究地点，样本是在 污水处理厂和下游污水处理厂、受污水影响的河流或监测井。 本研究中的一些污水处理厂对污水进行了连续和/或并行处理 收集了哪些单独的样本。例如，在一个 污水处理厂包括滴滤器和固体接触器（无硝化[NH3- N>10毫克/升]， 然后是用于氨氮去除的硝化滴滤器。另一个污水处理厂 两个平行处理过程:一列使用活性污泥（无硝化），而 其他列车采用先进的生物处理（硝化/反硝化）。 在2004年的湿/冷季节和干/暖季节采集样本，以及 第二年（2005年）又一次。第一年的两个采样事件基于水文学 以及治疗方面的考虑。在夏天，河流流量很低，所以一些河流的流量更大 以污水为主；而且，污水处理厂有更多的硝化作用。在冬天有更多 流量大，硝化作用少。这两个季节显示了水文和气候的不同影响 治疗在第二年，许多公用设施在提供特别服务的季节重新取样 该系统用于确定时间（年份）的信息数据- 年）的变化。包括9个参考文献、图表。

In addition to water recycling and reclamation programs, indirect potable reuse of wastewater has occurred over the past few decades, which will likely increase in the future as upstream wastewater treatment plants (WWTPs) discharge water into rivers or lakes that serve as downstream drinking water supplies. Indirect potable reuse can be defined as any watershed for a drinking WTP (DWTP) that contains point source discharges of wastewater; septic tanks adjacent to rivers may also alter the quality of the surface water. Drought and competing instream demands may result in <10- to >50-percent contribution of treated wastewater towards the stream flow. Attention has focused on pharmaceuticals and endocrine disruptors, but WWTPs are also sources of disinfection byproducts (DBPs), if chlorine disinfection is practiced, and DBP precursors. Biological wastewater treatment takes one of two general forms: suspended growth (biofloc) systems (e.g., activated sludge), and attached growth (biofilm) systems (e.g., trickling filter). Depending on operational conditions, both can operate as partial or complete nitrifying processes. Increased levels of nitrification decrease the concentrations of ammonia and organic nitrogen (amino) compounds. Nitrification transforms ammonia and organic nitrogen to nitrate. Suspended growth systems under anoxic conditions can denitrify (convert nitrate primarily to nitrogen gas). Treated wastewater (effluent organic matter [EfOM]) has been shown to be a source of precursors for a wide range of DBPs (trihalomethanes [THMs], haloacetic acids [HAAs], haloacetonitriles [HANs], and nitrosamines). The objective of this study was to evaluate the contribution of treated wastewater to DBP formation in drinking water supplies. The authors conducted a full-scale survey of approximately 20 WWTPs in the U.S. (in the west, southwest, the mountain region, south central, midwest, and northeast). WWTPs were sampled that used a range of treatment processes (oxidation ditch, aerated lagoon, trickling filters, activated sludge, nitrification/denitrification, soil aquifer treatment [SAT], powdered and/or granular activated carbon [PAC, GAC], membrane bioreactor [MBR], reverse osmosis [RO], or various combinations). For most of the study sites, samples were collected at the WWTPs and downstream DWTPs, effluent-impacted rivers or monitoring wells. Some of the WWTPs in this study had sequential and/or parallel treatment processes for which separate samples were collected. For example, the secondary treatment process at one WWTP included trickling filters and solids contactors (no nitrification [NH3-N >10 mg/L]), which were followed by nitrifying trickling filters for ammonia removal. Another WWTP had two parallel treatment processes: one train used activated sludge (no nitrification), whereas the other train used advanced biological treatment (nitrification/denitrification). Samples were collected during a wet/cold season and a dry/warm season in 2004, and once more in a second year (2005). The two sampling events in year 1 were based on hydrology and treatment considerations. In the summer, river flow is low, so some streams are more effluent-dominated; and, there is more nitrification at the WWTP. In the winter there is more flow and less nitrification. These two seasons showed the different impacts of hydrology and treatment. In year 2, many of the utilities were re-sampled in the season that provided especially informative data for that system to ascertain temporal (year-to-year) variations. Includes 9 references, figures.