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DOES THE CORONAVIRUS AFFECT CITY WATER SYSTEMS?
By Suzanne Forcese
The World Health Organization is calling it “public enemy number one.”
The recent outbreak of novel coronaviruses (COVID-19) in Wuhan City, China, is being closely monitored as it causes acute respiratory illness and has the potential to be fatal. The COVID-19 and the 2002 SARS-CoV (severe acute respiratory syndrome coronaviruses) are recent examples of how some coronaviruses that infect animals can evolve to infect humans.
Modern water and wastewater treatment systems play an important role in public health protection.
As the global health community tracks the spread of this virus, it’s important for water and wastewater professionals to keep updated on potential impacts. Investigations into the COVID-19 outbreak are ongoing and the information that is available now may change as more is learned.
The Coronavirus gets its name from its resemblance to a crown
Robert Haller, Executive Director of the Canadian Water and Wastewater Association, told WaterToday, that there is no formal position yet. “My committee is working with the Federal Government on a guidance document for our members. We put out similar guidance during H1N1 with suggestions for stocking up on critical supplies in case of supply chain disruption; establishing/reinforcing staff protocols for cleanliness and for staying home when sick; emergency staffing protocols for maintaining services.” Haller adds there is no need to stockpile water.
“We do not foresee water/wastewater operations being shut down. I would expect that water services will be seen as critical services in all municipalities.”
The Alberta Water and Wastewater Operators Association states in the resource information for Operators, “It is important to remember that an extensive body of literature on the effectiveness of water and wastewater treatment processes for coronaviruses is not available, and as always, site-specific water-quality and treatment-plant details may result in variation between full-scale effectiveness and research results found in the laboratory.”
WaterToday reached out to environmental scientist Nicole McLellan who has an academic background in environmental biology and civil engineering for drinking water treatment evaluations. We learned from a white paper she co-authored that:
Coronaviruses, named for the crown-like spikes on their surface, were first identified in the mid-1960’s. Currently 7 coronaviruses are known to infect people and make them ill. Three of these – MERS-CoV, SARS-CoV, and COVID-19 emerged in the last 20 years. COVID-19 is a new variety of coronavirus and is an enveloped, single-stranded RNA virus.
While it has been classified as a respiratory illness spread by coughing and sneezing, WT discovered a recent study dated February 2020, authored by Wang et al. that “diarrhea may be a secondary path of transmission.” According to epidemiologist David Fisman (University of Toronto) fecal spread could present new challenges to the virus’s containment but is more likely to be a problem inside hospitals.
The white paper co-authored by McLellan states, “The persistence of coronaviruses in hospital wastewater and domestic sewage is estimated to be 2-3 days (Wang et al.)”
The paper does provide encouragement noting that “coronaviruses have not been found to be more resistant to water treatment than other microorganisms such as E coli, phage, or human viruses such as poliovirus which are commonly used as surrogates for treatment performance evaluation.
Another encouraging observation suggests that the survival of coronaviruses is temperature dependent with greater survival at lower temperatures. As we warm up in Canada the virus is expected to lose its momentum.
Is the presence of coronavirus in sewage and wastewater treatment plants and in the aquatic environment now an issue?
“Should we be worried about the efficacy of water treatment filtration and disinfection processes for coronavirus removal and inactivation? The short answer is No… If we take proper precautions and risk considerations.”
“Common disinfection methods used in water and wastewater treatment are expected to be effective for inactivation of coronaviruses when executed properly.”
To be transferred via the water cycle, a virus must have the ability to survive human waste, retain its infectivity and come in contact with another person.
WaterToday learned from a 2008 study, “Survival of Coronaviruses in Water and Wastewater” (Patricia M. Gundy et al.) “Coronaviruses die off very rapidly in primary wastewater, with a 99.9% reduction in 2-3 days….Survival of the coronaviruses in primary wastewater was only slightly longer than secondary wastewater, probably due to the higher level of suspended solids that offer protection from inactivation.”
What about our drinking water? Health Canada states, “Based on published research, water treatment processes that meet virus removal/inactivation regulations are expected to be effective for coronaviruses control.”
The latest update from the World health Organization, March 8 2020, states:
“Currently there is no evidence on the survival of COVID-19 in drinking water or wastewater.”
While we are reminded that this virus does not appear to survive well in the environment and can be eliminated effectively by water treatment, especially chlorination, we still need to be aware that as the outbreak continues more experiments are needed before conclusions can be drawn.
Although a number of experts have weighed in, WT has received additional information from another wastewater expert -- George Thorpe, P. Eng.E.P., of BiPure Water. Thorpe’s statement is more cautionary and underscores the fact that we do not know everything about the virus.
“The Coronavirus could spread past a wastewater treatment plant as the virus isn’t destroyed by most treatment processes. Chlorination or other oxidation processes will stop the virus but these aren’t commonly used in wastewater treatment. With a life of 5 or more days, the virus could infect people swimming in a river downstream of the treatment plant.”
WaterToday also reminds everyone to follow the Do’s and Don’ts of general sanitation practices.
Do wash hands with soap and water for at least 20 seconds, especially after using the bathroom, before eating, after blowing your nose, coughing or sneezing
Do stay home when you are ill
Do cover your cough or sneeze with a tissue and dispose of the tissue in the trash
Do disinfect frequently touched objects and surfaces such as door knobs
Don’t touch your eyes, nose and mouth with unwashed hands
Don’t have close contact with people who are ill
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