Bren School of Environmental Science & Management, University of California, Santa Barbara, CA 93016, USA E-mail:
Department of Civil and Environmental Engineering, University of California, Irvine, CA 92697-2175, USA; Water-Energy Nexus Center, University of California, Irvine, CA 92697-2175, USA.
J Water Health. 2023 Sep;21(9):1242-1256. doi: 10.2166/wh.2023.128.
SARS-CoV-2 wastewater surveillance (WWS) at wastewater treatment plants (WWTPs) can reveal sewered community COVID-19 prevalence. For unsewered areas using septic tank systems (STSs) or holding tanks, how to conduct WWS remains unexplored. Here, two large STSs serving Zuma Beach (Malibu, CA) were studied. Supernatant and sludge SARS-CoV-2 concentrations from the directly-sampled STSs parameterized a dynamic solid-liquid separation, mass balance-based model for estimating the infection rate of users. Pumped septage before hauling and upon WWTP disposal was also sampled and assessed. Most (96%) STS sludge samples contained SARS-CoV-2 N1 and N2 genes, with concentrations exceeding the supernatant and increasing with depth while correlating with total suspended solids (TSS). The trucked septage contained N1 and N2 genes which decayed (coefficients: 0.09-0.29 h) but remained detectable. Over approximately 5 months starting in December 2020, modeled COVID-19 prevalence estimations among users ranged from 8 to 18%, mirroring a larger metropolitan area for the first 2 months. The approaches herein can inform public health intervention and augment conventional WWS in that: (1) user infection rates for communal holding tanks are estimable and (2) pumped and hauled septage can be assayed to infer where disease is spreading in unsewered areas.
污水处理厂的 SARS-CoV-2 污水监测 (WWS) 可以揭示污水系统中的 COVID-19 流行情况。对于使用化粪池系统 (STSs) 或储水池的非污水系统，如何进行 WWS 仍未得到探索。在这里，研究了两个为祖马海滩（加利福尼亚州马里布）服务的大型 STS。直接采样的 STS 的上清液和污泥中的 SARS-CoV-2 浓度参数化了一个动态固液分离模型，基于质量平衡的模型用于估计用户的感染率。在运输和处理到 WWTP 之前，还抽取和评估了泵送的化粪池污水。大多数（96%）STS 污泥样品含有 SARS-CoV-2 N1 和 N2 基因，浓度超过上清液，且随深度增加而增加，同时与总悬浮固体（TSS）相关。运输的化粪池污水含有 N1 和 N2 基因，这些基因会衰减（系数：0.09-0.29 h），但仍可检测到。从 2020 年 12 月开始的大约 5 个月内，用户中 COVID-19 的流行率估计值在 8%到 18%之间波动，在前两个月与更大的大都市区相吻合。本文中的方法可以为公共卫生干预提供信息，并增强传统的 WWS，原因是：（1）可以估计公共储水池用户的感染率；（2）可以对泵送和运输的化粪池污水进行检测，以推断未污水系统中疾病的传播范围。
