Drinking water strategies for small-scale systems: Avoiding unintended consequences of water regulations

加拿大较小的社区在向消费者提供安全饮用水方面面临着重大挑战。这些挑战源于这样一个事实，即向消费者提供高质量饮用水所需的技术和财政资源往往无法提供给小型供水商。因此，小社区的饮用水质量往往不能始终符合现有的加拿大饮用水质量（CDWQ）准则，而且可能无法满足日益严格的准则，这些准则包括新出现的污染物，这些污染物要么是由存在于原水中的化合物组成的，要么是由目前处理制度中形成的副产品组成的。卤乙酸（HAAs）就是一类新出现的污染物，加拿大卫生部和联邦-省-地区饮用水委员会目前正就其制定CDWQ准则。初步研究表明，加拿大许多小社区现有的饮用水系统将无法满足CDWQ对某些新出现的污染物（如HAAs）日益严格的指导方针。因此，可能需要制定关键策略来提高工厂中NOM的去除率或将二级消毒剂从游离氯改为氯胺。本项目将研究这两种处理方法，因为任何一种处理方法都可能对减少HAA的形成产生积极的结果，但会导致意想不到的水质变化（即，形成其他消毒剂副产物或增加氨氧化细菌的发生）。该研究项目将侧重于确定具有成本效益和实际可行的战略，以确保向小社区的消费者提供高质量的饮用水。

Smaller communities in Canada are faced with significant challenges in providing safe drinking water to consumers.  These challenges stem from the fact that the technical and financial resources needed to provide high quality drinking water to consumers are often not available to small water providers.  As a result, the drinking water quality in small communities often does not consistently meet existing Canadian Drinking Water Quality (CDWQ) guidelines, and likely cannot meet increasingly stringent guidelines that encompass emerging contaminants that either consist of compounds that are present in the raw source water or consist of by-products that are formed within current treatment regimes.  Haloacetic acids (HAAs) are one such group of emerging contaminants for which CDWQ guidelines are currently in the developmental stages by Health Canada and the Federal-Provincial-Territorial Committee on Drinking Water.  Preliminary studies have indicated that existing drinking water systems in many small communities across Canada will not be able to meet the increasingly stringent CDWQ guidelines for certain emerging contaminants like HAAs.  Therefore, key strategies may need to be developed to improve NOM removal in the plant or switch secondary disinfectants from free chlorine to chloramines.  This project will investigate both of these treatment approaches, as either could result in a positive result for mitigating HAA formation but result in an unintended water quality change (i.e., formation of other disinfectant by-products or increased occurrence of ammonia oxidizing bacteria).  This research program will focus on identifying cost-effective and practically feasible strategies that can be used to ensure high quality drinking water is delivered to consumers in small communities.