ABSTRACT
During the COVID-19 pandemic, wastewater from WWTPs became an interesting source of epidemiological surveillance. However, there is uncertainty about the influence of treatment type on virus removal. The aim of this study was to assess viral surveillance within wastewater treatment plants (WWTPs) based on different biological treatments. Seasonal monitoring (autumn-winter and spring-summer) was conducted in 10 Chilean rural WWTPs, which were based on activated sludge, aerated lagoons, bio-discs, constructed wetlands, vermifilters and mixed systems. Viruses were measured (influent/effluent) by the RT-qPCR technique, using a commercial kit for SARS-CoV-2, NoV GI, NoV GII, and HAV. The detection of SARS-CoV-2 viral variants by genotyping was performed using SARS-CoV-2 Mutation Assays (ThermoFisher Scientific, USA). JC polyomavirus detection (control), as well as a qPCR technique. Results showed that SARS-CoV-2, NoV GI and GII were detected in influents at values between <5 and 462, 0 to 28, and 0 to 75 GC/mL, respectively. HAV was not detected among the studied WWTPs. The monitored WWTPs removed these viruses at percentages between 0 and 100 %. WWTPs based on activated sludge with bio-discs demonstrated to be the most efficient at removing SARS-CoV-2 (up to 98 %) and NoV GI and GII (100 %). Meanwhile, bio-discs technologies were the least efficient for viral removal, due to biofilm detachment, which could also adsorb viral aggregates. A correlation analysis established that solids, pH, and temperature are the most influential parameters in viral removal. Wastewater-based surveillance at WWTP allowed for the detection of Omicron before the Chilean health authorities notified its presence in the population. In addition, surveillance of viruses and other microorganisms could help assess the potential public health risk of wastewater recycling.
Subject(s)
COVID-19 , Hepatitis A , Norovirus , Viruses , Water Purification , Humans , Wastewater , Sewage , SARS-CoV-2 , Chile/epidemiology , Pandemics , COVID-19/epidemiologyABSTRACT
During the COVID-19 pandemic, wastewater from WWTPs became an interesting source of epidemiological surveillance. However, there is uncertainty about the influence of treatment type on virus removal. The aim of this study was to assess viral surveillance within wastewater treatment plants (WWTPs) based on different biological treatments. Seasonal monitoring (autumn-winter and spring-summer) was conducted in 10 Chilean rural WWTPs, which were based on activated sludge, aerated lagoons, bio-discs, constructed wetlands, vermifilters and mixed systems. Viruses were measured (influent/effluent) by the RT-qPCR technique, using a commercial kit for SARS-CoV-2, NoV GI, NoV GII, and HAV. The detection of SARS-CoV-2 viral variants by genotyping was performed using SARS-CoV-2 Mutation Assays (ThermoFisher Scientific, USA). JC polyomavirus detection (control), as well as a qPCR technique. Results showed that SARS-CoV-2, NoV GI and GII were detected in influents at values between <5 and 462, 0 to 28, and 0 to 75 GC/mL, respectively. HAV was not detected among the studied WWTPs. The monitored WWTPs removed these viruses at percentages between 0 and 100 %. WWTPs based on activated sludge with bio-discs demonstrated to be the most efficient at removing SARS-CoV-2 (up to 98 %) and NoV GI and GII (100 %). Meanwhile, bio-discs technologies were the least efficient for viral removal, due to biofilm detachment, which could also adsorb viral aggregates. A correlation analysis established that solids, pH, and temperature are the most influential parameters in viral removal. Wastewater-based surveillance at WWTP allowed for the detection of Omicron before the Chilean health authorities notified its presence in the population. In addition, surveillance of viruses and other microorganisms could help assess the potential public health risk of wastewater recycling. Graphical Unlabelled Image
ABSTRACT
Viruses (e.g., SARS-CoV-2) are discharged into surface water bodies or agricultural irrigation from treated municipal/domestic wastewater. Therefore, this study aimed to evaluate the viral removal from wastewater treatment technologies, also considering wastewater physicochemical properties based on a bibliometric-statistical review. A preliminary bibliometric analysis (keywords co-occurrence) using VOS viewer (n = 698 scientific publications) was established. Moreover, systematic constraining criteria (1983–2021) limiting the statistical study to 93 scientific publications were carried out. Variance Analysis (ANOVA-2 ways) and Principal Component Analysis (PCA) were used to identify the most influential wastewater treatment typology and parameters affecting viral removal. Bibliometric results showed that at least 25% of the studies on viral removal from wastewater corresponded to the last 2 years. Therefore, SARS-CoV-2 was approached in a particular way. Thus, more than 15 viruses and/or genotypes and more than 20 specific/non-specific technologies for viral removal were statistically analyzed. Results did not report significant differences (p < 0.05) of Log Removal Virus (LRV) between specific (e.g., MBR, chlorination) and non-specific (e.g., activated sludge, anaerobic digestion) technologies. However, MBR (specific) and anaerobic digestion (non-specific) reported the highest viral removal efficiencies. SARS-CoV-2 has been reported to be removed by specific and non-specific technologies, but it is not conclusive. Preliminary statistical approximations establish that the physicochemical parameters (COD, TSS, pH) from wastewater could influence the viral removal. Future challenges should focus on operational improvements, new technology development, and regulation (recycling, discharge) assuming potential risks (human, environment).