COVID-19 Coronavirus and Water/Wastewater Treatment

Overview: Current Knowledge of COVID-19 Coronavirus Treatment at Water and Wastewater Facilities

by Megan Freytag and Christopher Boyd
Published in the Volume 8, Issue 7 of NCT Texas AWWA newsletter The Lake

(As of March 23, 2020) The ongoing coronavirus disease 2019 (COVID-19) pandemic has raised questions and concerns about the presence of the novel coronavirus in water and wastewater systems and the effectiveness of treatment processes. This article provides an overview of published information and studies regarding the spread and treatment of COVID-19.

 COVID-19 is a disease caused by the novel SARS-CoV-2 coronavirus[1] (referred to as COVID-19 coronavirus hereafter for simplicity). This virus is a member of the coronavirus family, which contains multiple viruses that are known to impact humans[2]. Among these are the viruses that cause severe acute respiratory syndrome (SARS), which was the source of an outbreak in 2003, and Middle East respiratory syndrome (MERS), which was the source of an outbreak in 2012. Since COVID-19 first appeared in Wuhan, China [1] in late 2019, it has spread around the world. Potential routes of transmission are listed on the Centers for Disease Control and Prevention (CDC) website and include close contact between people (within approximately six feet), contact with respiratory droplets (after an infected person coughs or sneezes), and contact with a contaminated surface followed by touching the mouth, nose, and potentially eyes[1]. The CDC advises that the agency is still learning how the virus spreads, so additional information may be released as the body of knowledge on the COVID-19 coronavirus increases.

One question facing the water community is whether or not the COVID-19 coronavirus is present in source water supplies and municipal wastewater.  Per the CDC, there is currently no known evidence of the survival of the COVID-19 coronavirus in water and sewer systems[1], and the World Health Organization (WHO) has stated that the risk to water supplies is low based on currently available information[3]. In terms of potential transmission through wastewater, several studies have isolated RNA (a type of genetic material) from the COVID-19 coronavirus in stool samples; however, the presence of RNA does not necessarily indicate the presence of infectious virus[1]. A review of other coronaviruses reveals that their viability in water and wastewater is not uniform. The 2003 SARS coronavirus was found to persist in domestic sewage for two days[5],  and viable virus was found in patient stool samples[1]. In contrast, the MERS coronavirus has only been found in respiratory tract samples[1]. The viability of the COVID-19 coronavirus in water and wastewater is yet to be determined. As of March 19, 2020, the World Health Organization (WHO) reported no cases of oral-fecal transmission of the COVID-19 coronavirus[3].

 Given the novelty of the COVID-19 coronavirus, specific information on its treatment in water and wastewater facilities is still being developed. In general terms, municipal water and wastewater treatment facilities include processes for the inactivation of viruses, and disinfection is a core part of the overall treatment strategy. Coronaviruses have a lipid outer envelope[2], meaning that they have a fragile outer membrane, are generally less stable in the environment, and are susceptible to oxidation-based disinfection methods such as chlorine[3]. For example, the related 2003 SARS coronavirus was found to be susceptible to chlorine and chlorine dioxide disinfection[5]. A presentation by the Water Environment Federation (WEF) on March 12, 2020 notes that disinfection requirements are based on inactivating pathogens that have equal or greater resistance to disinfection than lipid enveloped viruses and that oxidation-based disinfection chemicals (such as sodium hypochlorite and peracetic acid), as well as ultraviolet (UV) irradiation, should be effective at COVID-19 coronavirus inactivation[2]. The Environmental Protection Agency (EPA) has advised that standard water and wastewater treatment and disinfection practices are expected to be effective against the COVID-19 coronavirus[4].

Importantly, the COVID-19 pandemic is a constantly evolving situation, and new information can become available at any time. The following list provides links to some of the major agencies and industry groups involved in the COVID-19 pandemic response and includes information on hygiene and personal protective equipment (PPE) practices for operations staff:

Centers for Disease Control and Prevention: https://www.cdc.gov/
CDC, Water Transmission and COVID-19: https://www.cdc.gov/coronavirus/2019-ncov/php/water.html
 Environmental Protection Agency: https://www.epa.gov/
World Health Organization: https://www.who.int/
American Water Works Association: https://www.awwa.org/
Water Environment Federation: https://www.wef.org/
Texas Commission on Environmental Quality:  https://www.tceq.texas.gov/response/covid-19/tceq-preparedness-responsibilities-covid-19
Texas Water/Wastewater Agency Response Network: https://www.txwarn.org/

References:
[1] Coronavirus (COVID-19). Retrieved from Centers for Disease Control and Prevention: https://www.cdc.gov/coronavirus/2019-ncov/index.html 
[2] WRF Webcast Coronavirus Disease 2019 (COVID-19) Research update. Retrieved from Water Environment Federation: https://www.waterrf.org/system/files/resource/2020-03/Coronavirus_Webcast_031220_APPVDFINAL.v4.pdf
[3] Water, sanitation, hygiene, and waste management. (2020, March 19). Retrieved from World Health Organization : https://www.who.int/publications-detail/water-sanitation-hygiene-and-waste-management-for-covid-19
[4] Coronavirus and Drinking Water and Wastewater. Retrieved from Environmental Protection Agency : https://www.epa.gov/coronavirus/coronavirus-and-drinking-water-and-wastewater
[5] Wang XW, L. J. (2005). Study on the resistance of severe acute respiratory syndrome-associated coronavirus. Journal of Virological Methods , 171-177.