大温哥华水区（GVWD）为加拿大不列颠哥伦比亚省大温哥华地区的200万人供水。面对水质问题，包括潜在的水传播疾病、季节性浑浊、细菌再生和腐蚀性水，GVWD及其顾问和一个由北美各地水质和处理专家组成的技术审查委员会（TRB）评估了臭氧与氯在无过滤的初级消毒中的使用情况。考虑到臭氧、源水浊度、总有机碳水平（TOC）和氯需求量对贾第鞭毛虫和隐孢子虫的灭活作用，以及与臭氧相关的可同化有机碳（AOC）和可生物降解溶解有机碳（BDOC）的增加。 为了控制已经存在的再生问题，需要改进配水系统维护，如总水管冲洗和增加水库水周转率，以及增加氯增压站，以帮助维持余氯，这是臭氧氧化极其重要的先决条件。成立了由水处理、供水和实验室人员组成的配水系统水质委员会（DSWQC）。该委员会监测系统改进的有效性，并建议改变处理或流量策略，以维持水质。 离开所有设施的氯残留量可以增加或减少，或者水源水可以切换，以响应水源和分配系统中水质的变化。在这方面，DSWQC使用基于地理信息系统（GIS）的水质数据系统，该系统是专门为此目的开发的。这个用户友好的系统从地理上总结了2000平方公里范围内收集的在线和实验室数据。自2000年春季GVWD Coquitlam臭氧氧化设施投入运行以来，分配系统中的溶解氧和AOC水平大幅增加。 尽管如此，分配系统的改进和氯残留量的增加有效地将HPC和大肠菌群水平控制在可接受的水平。多学科、多辖区的任务组方法在制定和实施所用缓解策略方面非常有效。包括6个参考文献、表格、图表。

The Greater Vancouver Water District (GVWD) supplies water to two million people in the Greater Vancouver area of British Columbia, Canada. Faced with water quality concerns that included the potential for waterborne disease, seasonal turbidity, bacterial regrowth and corrosive water, the GVWD, its consultants and a Technical Review Board (TRB) consisting of water quality and treatment specialists from across North America evaluated the use of ozone versus chlorine for primary disinfection without filtration. The superior inactivation of Giardia and Cryptosporidium using ozone, source water turbidity, total organic carbon levels (TOC), and chlorine demand were considered along with the increases to Assimilable Organic Carbon (AOC) and Biodegradable Dissolved Organic Carbon (BDOC) associated with ozone. Improvements to distribution system maintenance such as water main flushing and increased reservoir water turnover plus the addition of chlorine booster stations to assist in maintaining a chlorine residual were needed to control an already existing regrowth problem and were extremely important pre-requisites to ozonation. A Distribution System Water Quality Committee (DSWQC) consisting of water treatment, water supply and laboratory personnel was formed. This committee monitors the effectiveness of enhancements to the system and recommends changes in either treatment or flow strategies to maintain water quality. Chlorine residuals leaving all facilities can be increased or decreased or source water can be switched to respond to changes in water quality both in the source and in the distribution system. In this role the DSWQC uses a Geographic Information System (GIS)-based water quality data system which was specifically developed for this purpose. The user-friendly system geographically summarizes on-line and laboratory data collected over a 2000 square kilometer area. Since the GVWD Coquitlam ozonation facility became operational in the spring of 2000, dissolved oxygen and AOC levels in the distribution system have increased substantially. In spite of that, distribution system improvements and increased chlorine residuals have effectively controlled HPC and coliform levels to acceptable levels. A multi-disciplinary and multi-jurisdictional task team approach has been very effective in developing and implementing the mitigation strategies used. Includes 6 references, tables, figures.