Conventional Wastewater Treatment Doesn’t Eliminate Risk of Covid Spread, Israeli Researchers Find

Spies can learn a lot about people from the garbage they produce. But even one’s sewage can reveal things about the residents of a home, a street and a neighborhood. 

A team at Ben-Gurion University (BGU) of the Negev in Beersheba are the first in the world to assess COVID-19 in wastewater. They identified SARS-CoV-2 survivability via RNA detection within sewage purification plants that could be used worldwide. Hey concluded that sewage must be treated beyond the conventional scheme so as to eliminate the new coronavirus. 

Their study, uploaded to the reprint archive medRxviv and due to undergo peer review soon, was titled “Tracking SARS-CoV-2 RNA through the wastewater treatment process.” 

Wastewater poses another threat of a renewed outbreak, they wrote. “Sewage workers are exposed to the virus through human feces and urine. If wastewater is left untreated, which occurs in some countries, it could infect people or animals who come into contact with it and perhaps create a mutated version. It could also affect water sources if sewage is dumped in open areas.”

In Israel, wastewater is collected, treated and then reused for agriculture. The BGU team analyzed samples of sewage collected during the first lockdown in April and during the current second wave in July. They found ample abundance of the virus’s RNA. 

“Most of the sewage in Israel and other developed countries undergoes biological treatment before release to the environment or reuse, but that was insufficient to reduce the virus concentration to undetectable levels,” the researchers wrote. Therefore, they urge wastewater to be further treated to minimize the risk of dissemination and infection. 

“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.”

In a couple of instances in which wastewater was treated by chlorine, the virus was no longer detectable. “If we do not want recurring waves of outbreaks, reducing the infection rate may not be enough, wastewater must be neutralized as well,” declared co-lead researcher Dr. Oded Nir of the Zuckerberg Institute for Water Research, part of BGU’s Jacob Blaustein Institutes for Desert Research at BGU. Prof. Ariel Kushmaro of the department of biotechnology engineering co-headed the study. 

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