Effect of selected wastewater characteristics on estimation of SARS-CoV-2 viral load in wastewater

Abstract

Wastewater-based epidemiology has been used as a tool for surveillance of COVID-19 infections. This approach is dependent on the detection and quantification of SARS-CoV-2 RNA in untreated/raw wastewater. However, the quantification of the viral RNA could be influenced by the physico-chemical properties of the wastewater. This study presents the first use of Adaptive Neuro-Fuzzy Inference System (ANFIS) to determine the potential impact of physico-chemical characteristics of wastewater on the detection and concentration of SARS-CoV-2 RNA in wastewater. Raw wastewater samples from four wastewater treatment plants were investigated over four months. The physico-chemical characteristics of the raw wastewater was recorded, and the SARS-CoV-2 RNA concentration determined via amplification with droplet digital polymerase chain reaction. The wastewater characteristics considered were chemical oxygen demand, flow rate, ammonia, pH, permanganate value, and total solids. The mean SARS-CoV-2 RNA concentrations ranged from 648.1(±514.6) copies/mL to 1441.0(±1977.8) copies/mL. Among the parameters assessed using the ANFIS model, ammonia and pH showed significant association with the concentration of SARS-CoV-2 RNA measured. Increasing ammonia concentration was associated with increasing viral RNA concentration and pH between 7.1 and 7.4 were associated with the highest SARS-CoV-2 concentration. Other parameters, such as total solids, were also observed to influence the viral RNA concentration, however, this observation was not consistent across all the wastewater treatment plants. The results from this study indicate the importance of incorporating wastewater characteristic assessment into wastewater-based epidemiology for a robust and accurate COVID-19 surveillance.

A wastewater-based epidemic model for SARS-CoV-2 with application to three Canadian cities

“…For Edmonton and Toronto, SARS-CoV-2RNA was extracted from the solid fraction of influent samples. The solid concentration can be affected by the influent flow volume and environmental factors such as precipitation and sedimentation Bertels et al, 2022 , Amoah et al, 2022 . Hence, for these locations, SARS-CoV-2concentrations in wastewater was normalized by the total solid suspension (TSS) measured on the sampling day at the treatment plant.…”

Making waves: Wastewater surveillance of SARS-CoV-2 in an endemic future

“…Furthermore, the lack of clinical viral shedding data from vaccinated (single or multiple doses) and unvaccinated individuals, patients with varied severity of symptoms, as well as across SARS-CoV-2 variants also hampers a wide range of WBE endeavours, including calculating the incidence of infection in sewersheds, estimating the effective reproduction number of SARS-CoV-2 in a population ( Huisman et al, 2021 ) and inferring transmission fitness of VOCs from wastewater data ( Caduff et al, 2021 ). On the other hand, viral concentrations in wastewater are impacted by the transient flow rates, water pH, viral degradation and detention in wastewater lines ( Amoah et al, 2022 ; Khan et al, 2021 ; Simpson et al, 2021 ), further undermining WBS data applications.…”

An assessment of hospital wastewater and biomedical waste generation, existing legislations, risk assessment, treatment processes, and scenario during COVID-19

“…Previous studies have reported that SARS-CoV-2 can mostly survive when the pH of the HWW is between 6 and 8 ( Amoah et al, 2022 ; Varbanov et al, 2021 ). La Rosa et al (2020) have reported SARS-CoV-2 is highly sensitive to alkaline water and can be inactivated in chlorinated water ( La Rosa et al, 2020 ).…”