Stamps Blake W, Leddy Menu B, Plumlee Megan H, Hasan Nur A, Colwell Rita R, Spear John R
Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO, United States.
Department of Research and Development, Orange County Water District, Fountain Valley, CA, United States.
Front Microbiol. 2018 Oct 26;9:2435. doi: 10.3389/fmicb.2018.02435. eCollection 2018.
Conventional water resources are not sufficient in many regions to meet the needs of growing populations. Due to cyclical weather cycles, drought, and climate change, water stress has increased worldwide including in Southern California, which serves as a model for regions that integrate reuse of wastewater for both potable and non-potable use. The Orange County Water District (OCWD) Advanced Water Purification Facility (AWPF) is a highly engineered system designed to treat and produce up to 100 million gallons per day (MGD) of purified water from a municipal wastewater source for potable reuse. Routine facility microbial water quality analysis is limited to standard indicators at this and similar facilities. Given recent advances in high throughput DNA sequencing techniques, complete microbial profiling of communities in water samples is now possible. By using 16S/18S rRNA gene sequencing, metagenomic and metatranscriptomic sequencing coupled to a highly accurate identification method along with 16S rRNA gene qPCR, we describe a detailed view of the total microbial community throughout the facility. The total bacterial load of the water at stages of the treatment train ranged from 3.02 × 10 copies in source, unchlorinated wastewater feed to 5.49 × 10 copies of 16S rRNA gene/mL after treatment (consisting of microfiltration, reverse osmosis, and ultraviolet/advanced oxidation). Microbial diversity and load decreased by several orders of magnitude after microfiltration and reverse osmosis treatment, falling to almost non-detectable levels that more closely resembled controls of molecular grade laboratory water than the biomass detected in the source water. The presence of antibiotic resistance genes and viruses was also greatly reduced. Overall, system design performance was achieved, and comprehensive microbial community analysis was found to enable a more complete characterization of the water/wastewater microbial signature.
在许多地区，常规水资源不足以满足不断增长的人口需求。由于周期性天气循环、干旱和气候变化，全球范围内包括南加州的水资源压力都有所增加，南加州是一个将废水再利用用于饮用水和非饮用水的地区典范。橙县水区（OCWD）先进水净化设施（AWPF）是一个经过高度工程设计的系统，旨在处理并从城市污水源中每天生产多达1亿加仑（MGD）的净化水用于饮用水再利用。在此设施及类似设施中，常规的设施微生物水质分析仅限于标准指标。鉴于高通量DNA测序技术的最新进展，现在可以对水样中的微生物群落进行完整的微生物谱分析。通过使用16S/18S rRNA基因测序、宏基因组和宏转录组测序，并结合一种高度准确的鉴定方法以及16S rRNA基因定量PCR，我们描述了整个设施中总微生物群落的详细情况。处理流程各阶段水中的细菌总负荷范围从源水（未氯化的废水进水）中的3.02×10拷贝到处理后（包括微滤、反渗透和紫外线/高级氧化）的5.49×10拷贝的16S rRNA基因/毫升。经过微滤和反渗透处理后，微生物多样性和负荷降低了几个数量级，降至几乎不可检测的水平，与分子级实验室用水的对照更相似，而不是源水中检测到的数据。抗生素抗性基因和病毒的存在也大大减少。总体而言，实现了系统设计性能，并且发现全面的微生物群落分析能够更完整地表征水/废水的微生物特征。
