硝化作用是全国许多饮用水库和配水系统中遇到的一个主要问题。硝化事件导致消毒剂残留量突然下降、亚硝酸盐水平高、异养平板计数高，偶尔出现大肠菌群，包括大肠杆菌的存在。纠正措施既昂贵又费力，通常只能在短时间内缓解问题，并在几周或几个月内恢复硝化作用。 为了解决这一问题，开展了一项研究，目的是确定饮用水库中调节或与硝化作用和大肠菌群发生相互作用的微生物种群和物理化学条件。本研究的目的是确定指示或促进硝化细菌和大肠菌群的建立和后续生长，以及触发硝化和大肠菌群事件的特定参数。为了解决这个问题，从三个成品中收集了液体和生物膜样本- 每月对水库进行检查。此外，还进行了补充实验以评估:最常用的纠正程序（超氯化）的效果；硝化细菌和大肠菌群的定植顺序；以及不同水深的硝化细菌和大肠菌群的存在。为了研究生物膜，在两个不同的深度放置与水库（混凝土或涂层钢）相同材料制成的试样，以评估水位波动的影响。还对样本进行了硝化细菌、大肠菌群和大肠杆菌的监测。 大肠杆菌，以及各种物理和化学参数。在所有储层、所有深度的液体和生物膜样品中均检测到氨氧化细菌（AOB）。它们是在生物膜形成的早期阶段（放置试片后3天）检测到的。一般来说，放置在水库底部（持续淹没的区域）的生物膜试片上的HPC和AOB水平高于水库顶部（间歇性暴露于空气中）。在液体样本中，上游水库的HPC和AOB水平高于两个下游水库，考虑到上游水库中测得的水停留时间较短，氯残留较高，这令人惊讶。 结果表明，水库循环并不能完全阻止硝化作用的发生。超氯化有效地降低了液体和生物膜样品中的生物量浓度，尽管经验表明硝化作用可能在几周或几个月内再次发生。包括7个参考文献、图表。

Nitrification is a major problem encountered in many drinking water reservoirs and distribution systems across the country. Nitrification episodes are responsible for a sudden drop in disinfectant residuals, high nitrite levels, high heterotrophic plate counts (HPCs), and occasionally coliform occurrences, including the presence of Escherichia coli. The corrective measures are expensive and laborious, and usually only mitigate the problem for a short period of time, with a return to nitrification within a few weeks or months. To address this problem, a study was undertaken with the goal of identifying the microbial populations and the physicochemical conditions that mediate or interact with nitrification and coliform occurrences in drinking water reservoirs. The goal of this study was to identify the specific parameter(s) that indicate or facilitate theestablishment and subsequent growth of nitrifying and coliform bacteria, and trigger nitrification and coliform episodes. To address this, liquid and biofilm samples were collected from three finished-water reservoirs on a monthly basis. In addition, supplemental experiments were conducted to evaluate: the effect of the most commonly used corrective procedure (superchlorination); the sequence of colonization of nitrifying and coliform bacteria; and, the presence of nitrifying and coliform bacteria at different water depths. To study the biofilm, coupons made of the same material as the reservoirs (concrete or coated steel) were placed at two different depths to evaluate the effects of water level fluctuation. Samples were also monitored for nitrifying bacteria, coliforms and E. coli, as well as for a variety of physical and chemical parameters. Ammonia oxidizing bacteria (AOB) were detected in all reservoirs, at all depths, in both liquid and biofilm samples. They were detected at a very early stage of biofilm formation (3 days following coupon placement). In general, higher HPC and AOB levels were measured on the biofilm coupons placed on the bottom of the reservoirs (area constantly submerged) than on top of the reservoirs (intermittently exposed to air). In the liquid samples, the upstream reservoir exhibited higher HPC and AOB levels than the two downstream reservoirs, which is surprising considering the lower water residence time and higher chlorine residual measured in the upstream reservoir. Results indicate that reservoir cycling does not completely prevent nitrification from occurring. Superchlorination effectively decreased biomass concentrations in both liquid and biofilm samples, although experience has shown that nitrification may re-occur within a period of a few weeks or months. Includes 7 references, figures.