Sanitary Engineering, Delft University of Technology, Stevinweg 1, 2628CN Delft, the Netherlands; Partners4UrbanWater, Graafseweg 274, 6532 ZV Nijmegen, the Netherlands.
Partners4UrbanWater, Graafseweg 274, 6532 ZV Nijmegen, the Netherlands.
Sci Total Environ. 2023 Mar 20;865:161196. doi: 10.1016/j.scitotenv.2022.161196. Epub 2022 Dec 26.
Over the course of the Corona Virus Disease-19 (COVID-19) pandemic in 2020-2022, monitoring of the severe acute respiratory syndrome coronavirus 2 ribonucleic acid (SARS-CoV-2 RNA) in wastewater has rapidly evolved into a supplementary surveillance instrument for public health. Short term trends (2 weeks) are used as a basis for policy and decision making on measures for dealing with the pandemic. Normalisation is required to account for the dilution rate of the domestic wastewater that can strongly vary due to time- and location-dependent sewer inflow of runoff, industrial discharges and extraneous waters. The standard approach in sewage surveillance is normalisation using flow measurements, although flow based normalisation is not effective in case the wastewater volume sampled does not match the wastewater volume produced. In this paper, two alternative normalisation methods, using electrical conductivity and crAssphage have been studied and compared with the standard approach using flow measurements. For this, a total of 1116 24-h flow-proportional samples have been collected between September 2020 and August 2021 at nine monitoring locations. In addition, 221 stool samples have been analysed to determine the daily crAssphage load per person. Results show that, although crAssphage shedding rates per person vary greatly, on a population-level crAssphage loads per person per day were constant over time and similar for all catchments. Consequently, crAssphage can be used as a quantitative biomarker for populations above 5595 persons. Electrical conductivity is particularly suitable to determine dilution rates relative to dry weather flow concentrations. The overall conclusion is that flow normalisation is necessary to reliably determine short-term trends in virus circulation, and can be enhanced using crAssphage and/or electrical conductivity measurement as a quality check.
在 2020 年至 2022 年期间的冠状病毒病-19（COVID-19）大流行期间，对污水中严重急性呼吸系统综合征冠状病毒 2 核糖核酸（SARS-CoV-2 RNA）的监测迅速发展成为公共卫生的补充监测手段。短期趋势（2 周）被用作制定应对大流行措施的政策和决策的基础。需要归一化，以考虑到由于时间和位置相关的雨水、工业排放和外来水的下水道流入，生活污水的稀释率会强烈变化。污水监测的标准方法是使用流量测量进行归一化，尽管基于流量的归一化在采样的污水量与产生的污水量不匹配的情况下无效。在本文中，研究了两种替代的归一化方法，即使用电导率和 crAssphage，并将其与使用流量测量的标准方法进行了比较。为此，在 2020 年 9 月至 2021 年 8 月期间，在九个监测地点共收集了 1116 个 24 小时流量比例样本。此外，还分析了 221 个粪便样本，以确定每人每天的 crAssphage 负荷。结果表明，尽管每人 crAssphage 的脱落率差异很大，但在人口水平上，每人每天的 crAssphage 负荷随时间保持不变，并且在所有集水区都相似。因此，crAssphage 可用于 5595 人以上的人群作为定量生物标志物。电导率特别适合用于确定相对于干天气流浓度的稀释率。总体结论是，为了可靠地确定病毒循环的短期趋势，需要进行流量归一化，并且可以使用 crAssphage 和/或电导率测量作为质量检查来增强。
