Tracking SARS-CoV-2 RNA through the wastewater treatment process

Abstract

The municipal sewage carries the new coronavirus (SARS-CoV-2), shed by COVID-19 patients, to wastewater treatment plants. Proper wastewater treatment can provide an important barrier for preventing uncontrolled discharged of the virus into the environment. However, the role of the different wastewater treatment stages in reducing virus concentrations was, thus far, unknown. In this work, we quantified SARS-CoV-RNA in the raw sewage and along the main stages of the wastewater process from two different plants in Israel during this COVID-19 outbreak. We found that ca. 2 Log removal could be attained after primary and secondary treatment. Despite this removal, significant concentrations of SARS-CoV-RNA (>100 copies per mL) could still be detected in the treated wastewater. However, after treatment by chlorination, SARS-CoV-RNA was detected only once, likely due to insufficient chlorine dose. Our results highlight the need to protect wastewater treatment plants operators, as well as populations living near areas of wastewater discharge, from the risk of infection. In addition, our results emphasize the capabilities and limitations of the conventional wastewater treatment process in reducing SARS-CoV-RNA concentration, and present preliminary evidence for the importance of tertiary treatment and chlorination in reducing SARA-CoV-2 dissemination.

Processos Convencionais E Promissores De Inativação Ou Remoção Do Sars-Cov-2 De Esgotos: Revisão De Princípios E Mecanismos De Ação

“…Ressalta-se que, embora relatos tenham indicado que as unidades secundárias de tratamento tenham sido capazes de remover e inativar parcelas significativas de vírus entéricos (YANG et al, 2020;, as unidades não têm sido capazes de remover de forma completa o SARS-CoV-2 em plantas de tratamento de águas residuais em escalas reais (MOHAN et al, 2021;SERRA-COMPTE et al, 2021). De acordo com estudos procedidos em ETEs na Espanha, Japão, Israel e Índia, fragmentos do genoma do SARS-CoV-2 ainda foram capazes de ser detectados em amostras de efluentes secundários (ALI et al, 2020;HARAMOTO et al, 2020;RANDAZZO et al, 2020;KUMAR et al, 2021). Embora os processos secundários relatados nos estudos tenham apresentado diferenças operacionais significativas, a implementação de unidades terciárias de tratamento foi fortemente recomendada com o intuito de reduzir a possibilidade de propagação do SARS-CoV-2 através das matrizes aquáticas.…”

“…Ressalta-se, entretanto, que a eficiência da inativação das partículas virais, incluindo de vírus envelopados como SARS-CoV-2, tem sido influenciada por diversos fatores críticos, como o tempo de contato, dose, pH, temperatura e composição de águas residuais/água (MOHAN et al, 2021), além das condições de manutenção e operação das estações de tratamento (NASSERI et al, 2021). Estudos realizados em plantas de tratamento de esgoto reais no Irã e Israel, por exemplo, indicaram que o processo de terciário de cloração não foi 100% eficaz na remoção de material genético do SARS-CoV-2 das águas residuais em tratamento (ALI et al, 2020;NASSERI et al, 2021).…”

“…Adicionalmente, o SARS-CoV-2, caso presente em esgotos e águas naturais, tem levantado a possibilidade da propagação do novo coronavírus em animais selvagens e domesticados que propiciariam a disseminação e adaptação evolutiva do patógeno através de infecções cruzadas (FAGRE et al, 2020;WARTECKI & RZYMSKI, 2020;DELAHAY et al, 2021). Embora os tratamentos convencionais, constituídos em sua grande maioria de etapas de sedimentação primária, digestão biológica e cloração, tenham sido capazes de desinfectar uma parcela significativa do SARS-CoV-2 de esgotos contaminados, em alguns casos, os processos têm se demonstrado ineficientes em remover por completo as partículas do genoma desse vírus (ALI et al, 2020;AMPUERO et al, 2020;WURTZER et al, 2020).…”

Early detections of SARS-CoV-2 in wastewater and their use in COVID-19 epidemiological control

“…The Research, Society and Development, v. 10, n. 5, e45910515219, 2021 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v10i5.15219 8 studies have been carried out to determine the efficiency of disinfection systems and foment strategies regarding the adequacy of water and wastewater treatment plants, waste transport and discharge procedures (Cahill & Morris 2020;Zhang et al 2020b;Patel et al 2021). The researches have also aimed to analyze the safety of reused wastewaters in irrigation of food crops, groundwater recharge, cooling industrial processes and recreation porpoises (Ali et al 2020;Bogler et al 2020;Jha et al 2020).…”

A mass balance approach for quantifying the role of natural decay and fate mechanisms on SARS‐CoV‐2 genetic marker removal during water reclamation

“…However, neither study quantified the contribution of identified factors toward the removal of genetic markers. Observations of increased SARS-CoV-2 genetic marker adsorption in thickened primary and waste activated sludge matrices are widely understood (Abu Ali et al, 2021;Aghababaei et al, 2023;Yanaç et al, 2022) to be a primary pathway for virus removal during wastewater treatment. To the best of our knowledge, a long-term study identifying and quantifying the impact of natural decay and fate mechanisms, including adsorption, on the removal of viruses during wastewater treatment has not been conducted or reported in the literature.…”