What You Need to Know
‣ Human waste from people with Covid-19 contains the virus SARS-CoV-2 that causes the disease. This viral load may remain for several days after a patient’s respiratory tract tests negative for the virus.
‣ During the pandemic, huge viral loads are present in municipal wastewater systems.
‣ Data support the notion that the virus is viable in the environment for prolonged periods under some conditions, facilitating environmental contamination and potential transmission from direct exposure to untreated waste, including the inhalation of aerosols.
‣ Standard occupational safety measures are thought to be effective in protecting against the corona virus in sewage; however, municipal wastewater facilities are advised to:
- Review occupational safety measures in light of this new information and uncertainty, adjusting measures as required;
- Ensure staff have adequate personal protective equipment (PPE); and,
- Promote awareness among facility operators and the use of PPE to avoid inadvertent contact with sewage, including the inhalation of very fine particles suspended in the air.
‣ Analysis of sewage at municipal wastewater facilities enables local governments to monitor the sewage to detect the relative presence of the disease in a population, including asymptomatic carriers, and to act as an early warning system for resurgent out-breaks.
‣ This information will inform healthcare and economic mitigation efforts and policy.
‣ Research to determine the potential for fecal–oral transmission of SARS-CoV-2 and the viability of the virus in various environmental conditions.
‣ Research to quantify the presence SARS-CoV-2 in sewage and calibrate surveillance data, enhancing its utility as a tool in the fight against this latest coronavirus and its circulation.
The Bigger Problem
‣ While typical disinfection practices of wastewater treatment facilities effectively eliminate the viral load in treated wastewater before it is returned to the environment, populations without adequate sanitation may face increased risk of transmission.
‣ Populations with inadequate water and wastewater treatment may serve as a refuge for the virus, potentially sustaining the pandemic.
My synopsis of the current situation is this:
- The fact that there are viruses in water may not necessarily present an acute health problem for WWT workers; however, if inadvertent ingestion is a viable pathway for infection, the virus is more likely to be inhaled as a source of infection.
- There can be tremendous aerosol formation in a WWT plant from different methods of aeration – bubbles rising out the water from diffused or jet systems, surface mixers churning water and atmospheric air, as well as cascade systems, brush rollers and many other traditional aeration systems.
Chris Milligan, CEO and Chief Engineer at BlueInGreen – a water cleantech company based in Fayetteville, AR – sums up the current situation.
“The issue at the moment is uncertainty. We just don’t know the risks, so municipal WWT workers may want to err on the side of caution. If research finds that ingestion is a pathway for the disease, then technologies that don’t splash or bubble up - like what we provide at BlueInGreen - will be of paramount importance.”
Special thanks to Dr. Paula A.D. Vilela, PhD from the University of São Paulo (USP) for directing me to various technical notices and information sources contained herein, including many discussions about the current situation in Brazil and the deliberations among her peers on the subject. Dr. Vilela is a professional engineer and respected authority in the subjects of Wastewater, Water Reuse and Project Management in Latin America, working with multinational industrial clients and Municipalities.
¹ US Environmental Protection Agency: An emerging contaminant is a chemical or material characterized by a perceived, potential, or real threat to human health or the environment or by a lack of published health standards. [Emphasis added.]
² US Geological Survey: Any synthetic or naturally occurring chemical or any microorganism that is not commonly monitored in the environment but has the potential to enter the environment and cause known or suspected adverse ecological and (or) human effects. [Emphasis added.]
³ English Translation of Portuguese Technical Notice.
⁴ English Translation of Portuguese Technical Notice, March 30, 2020.
⁶ National Sanitation Information System Water and Sewage Services Diagnostic Report – 2016.
⁷ 2016, National Sanitation Information System, Water and Sewage Services Diagnostic Report.
⁸ 2018, National Sanitation Information System, Water and Sewage Services Diagnostic Report.
¹⁰ Favella: A shantytown in or near a city, especially in Brazil; a slum area.
¹¹ English translation of Portuguese Technical Notice, March 30th, 2020.
¹² 2018, National Sanitation Information System.
¹³ “Industry Scenario.” Aegea.