New WEF report suggests ‘low’ COVID-19 risk for wastewater workers, but calls for further study


A blue-ribbon panel of 16 wastewater sector experts that convened in April has determined in a new report that the occupational risk of COVID-19 infection for wastewater workers is low, but also identified the need for two additional studies to close existing knowledge gaps.

The new 114-page report from the Water Environment Federation (WEF), “Protecting Wastewater Professionals From COVID-19 and Other Biological Hazards“, re-examines approaches to managing biological hazards in general.

“The top priority of WEF is always to ensure the safety and health of our frontline people, who are essential workers in communities across the country,” announced WEF President Jackie Jarrell, in a statement. “We are grateful to the blue-ribbon panel for ensuring that information on hazards and safety are based on the latest evidence and best science,” added Jarrell.

Although the virus’ ribonucleic acid (RNA) has been detected in untreated wastewater, no reports have yet shown infectious forms of the virus in wastewater, indicating that COVID-19 requires living host cells to reproduce. The report’s panelists concluded the virus is unlikely to be more infectious than other types of viruses typical to wastewater environments.

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The panel notes, however, that although the infectious form of the virus that causes COVID-19 has not yet been detected in wastewater, wastewater sludge, or biosolids, its presence cannot be ruled out without further research.

The WEF provides guidance for managing many forms of biological hazards in its 2012 publication, Manual of Practice (MOP) 1: Safety, Health, and Security in Wastewater Systems. The latest report suggests that there is no basis for new changes to that guidance beyond further emphasizing the importance of proper protective equipment to protect workers’ respiratory pathways, such as N95 respirators, surgical masks, and goggles.

“Standard treatment and disinfection procedures in use at water resource recovery facilities have proven effective at inactivating the virus,” the report states. “Employing proper personal protective equipment and hygienic practices can sufficiently protect workers from virus exposure, according to the findings.”

The report states that because COVID-19 mainly spreads through respiratory droplets, tasks that involve spraying wastewater or biosolids as an aerosol “could present increased inhalation risks.” Additionally, collection system workers, biosolids handlers, laboratory analysts, industrial pretreatment personnel, and other hands-on jobs may also face increased exposure, the report’s authors wrote.

Further COVID-19 Wastewater Research Needed

Perhaps most notably, the latest WEF report has identified the need for two additional studies. First, an epidemiological study of infectious disease incidence among wastewater and collection system workers that could establish a baseline level of protective equipment use for COVID-19; and second, a new study to characterize respiratory exposure for typical tasks performed by workers in water resource recovery facilities and collection systems, “aimed at better identifying aerosolization effects and other understudied disease vectors,” the report’s authors state.

“Existing research provides an incomplete understanding of how transitioning between solid and liquid phases during the wastewater treatment process can affect any virus transmission, a knowledge gap exacerbated by coronavirus,” the report states.


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