Via Department of Civil and Environmental Engineering , Virginia Tech , Blacksburg , Virginia 24061 , United States.
Water Resources Research Center , University of Arizona , Tucson , Arizona 85719 , United States.
Environ Sci Technol. 2018 Aug 21;52(16):9056-9068. doi: 10.1021/acs.est.8b02818. Epub 2018 Aug 2.
Need for global water security has spurred growing interest in wastewater reuse to offset demand for municipal water. While reclaimed (i.e., nonpotable) microbial water quality regulations target fecal indicator bacteria, opportunistic pathogens (OPs), which are subject to regrowth in distribution systems and spread via aerosol inhalation and other noningestion routes, may be more relevant. This study compares the occurrences of five OP gene markers ( Acanthamoeba spp., Legionella spp., Mycobacterium spp., Naegleria fowleri, Pseudomonas aeruginosa) in reclaimed versus potable water distribution systems and characterizes factors potentially contributing to their regrowth. Samples were collected over four sampling events at the point of compliance for water exiting treatment plants and at five points of use at four U.S. utilities bearing both reclaimed and potable water distribution systems. Reclaimed water systems harbored unique water chemistry (e.g., elevated nutrients), microbial community composition, and OP occurrence patterns compared to potable systems examined here and reported in the literature. Legionella spp. genes, Mycobacterium spp. genes, and total bacteria, represented by 16S rRNA genes, were more abundant in reclaimed than potable water distribution system samples ( p ≤ 0.0001). This work suggests that further consideration should be given to managing reclaimed water distribution systems with respect to nonpotable exposures to OPs.
全球水安全的需求促使人们越来越关注废水再利用，以抵消对市政用水的需求。虽然回收（即不可饮用）微生物水质法规针对粪便指示菌，但机会性病原体（OPs）可能更相关，OPs 在分配系统中易于再生，并通过气溶胶吸入和其他非摄入途径传播。本研究比较了五种 OP 基因标记物（棘阿米巴属、军团菌属、分枝杆菌属、福氏耐格里阿米巴、铜绿假单胞菌）在回收水和饮用水分配系统中的出现情况，并分析了可能导致其再生的因素。在四个采样事件中，从处理厂出水的合规点和四个同时具有回收水和饮用水分配系统的美国公用事业的五个使用点采集了样本。与这里检查的和文献报道的饮用水系统相比，回收水系统具有独特的水化学特性（例如，营养物质升高）、微生物群落组成和 OP 出现模式。回收水分配系统样品中军团菌属基因、分枝杆菌属基因和 16S rRNA 基因代表的总细菌比饮用水分配系统样品更为丰富（p ≤ 0.0001）。这项工作表明，应该进一步考虑管理回收水分配系统，以减少非饮用性接触 OPs。
