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Study warns of the need to evaluate the presence of viruses in Wastewater Treatment Plants

Study warns of the need to evaluate the presence of viruses in Wastewater Treatment Plants

A study carried out by a team from the Faculty of Pharmacy of the University of Coimbra (FFUC) concluded that the current methods used in Wastewater Treatment Plants (ETAR) are not effective in removing the most resistant viruses.

Analyzes carried out on samples collected at 15 WWTPs from north to south of the country revealed the presence of high amounts of genetic material from some viruses, such as polyomavirus JC and Norovirus.

Polyomavirus JC is a very little known virus, although very common among the human population. However, this virus only causes disease in individuals who have a very compromised immune system, which can happen due to several pathologies. In these patients, the JC virus can cause Multifocal Progressive Leukoencephalopathy (PML), a central nervous system demyelinating disease that can be fatal. The Norovirus group is one of the main responsible for gastroenteritis and can be transmitted through the ingestion of contaminated food or water.

As there is no legislation at national or European level regulating the presence of viruses in treated wastewater, this study focused on detecting and quantifying the existence of the most resistant viruses' with the aim of drawing attention competent authorities and policy makers on the need to include this assessment in WWTP in order to avoid risks to human health. The effluents from WWTPs are introduced into the water resources for reuse, and can be a way of transporting these viruses to the population," says Ana Miguel Matos, study coordinator and professor at the Faculty of Pharmacy of the University of Coimbra.

"We do not intend to cause alarmism, but to produce information that leads to the implementation of new practices for assessing the quality of the water leaving the WWTP to prevent the spread of viruses", reiterates the researcher.

In order to evaluate to what extent the current wastewater treatment methods practiced by the different WWTPs are effective in the destruction of viruses, the analyzes were carried out in untreated sewage (influent harvested at the entrance of the WWTP) and in the respective effluents (at the exit of the WWTP) .

Thus, at the entrance of WWTP, JC virus appeared in 14 of the 15 studied, with concentration levels of 538 thousand virus per liter. After treatment, the JC virus genome remained detectable in 8 WWTPs, albeit at lower concentrations (213,000 viruses per liter). In the case of Noroviruses, their presence (before any treatment) was also detected in 14 WWTPs but in higher concentrations: one million viruses per liter. At the exit, the virus remained in 10 WWTP, in concentrations of 266 thousand virus per liter.

The researchers also verified that the permanence of these viruses at the exit of the WWTP is independent of the treatment methods applied by each of them.

The next phase of the study will be to verify if these two viruses resist an innovative method of wastewater treatment that is being developed by a team of researchers from the Department of Chemical Engineering of the Faculty of Sciences and Technology of the University of Coimbra.
The method in question combines the use of photocatalytic ozone and biofilters with a freshwater clamshell known as Asian clams (Corbicula fluminea) to remove viruses and bacteria from wastewater.

Cristina Pinto
Coimbra University

Translated from the Portuguese version of Pravda.Ru by
Ekaterina Santos