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Corona Update: Wastewater Treatment Plants

Information of the DWA Technical Committee BIZ-4 "Occupational Health and Safety".


The Federal Institute for Occupational Health and Safety (BAuA), which is responsible for occupational health and safety, published a new risk assessment on 09.04.2020:

"According to the current state of knowledge, transmission of SARS-CoV-2 via the wastewater route is very unlikely. A risk from SARS-CoV-2 for employees at and in waste water technical plants outside the medical sector does not exist to the best of our knowledge. Molecular biological detection of the genetic material of the virus in wastewater is not equivalent to its infectivity. The disease is transmitted via direct contact with those infected rather than in direct contact with sickly persons. Nevertheless, protective measures, as formulated in TRBA 220 (Health and safety in activities with biological agents in waste water technical plants), must be observed.

In response to a telephone enquiry by the DWA on 16.04.2020, the BAuA explained the following:

In this context, work within medically used areas means work that takes place on wastewater installations that are directly connected to medically used rooms such as isolation or quarantine stations. Here, under certain circumstances, a direct risk of infection SARS-CoV-2 via aerosols is possible. Such work may only be carried out in strict compliance with TRBA 250 (Technical Rules for Biological Agents in Health Care). Sewage engineering systems outside clinics, hospitals or nursing homes are not affected by this.

On 27 March 2020 the Federal Environment Agency (UBA) published the following risk assessment for transmission via waterways under the title "Effects of the COVID 19 pandemic on bathing waters":

"According to the WHO (World Health Organisation), there is no evidence to date that the SARS coronavirus-2 (SARS CoV-2) is transmitted by water. In contrast to infections with noroviruses, for example, which only cause diarrhoea, only a few COVID-19 patients excrete viruses in the stool. Initial studies have shown that only about 2% to 10% of COVID-19 patients had diarrhoea. Infectious corona viruses in stool were only detected in isolated cases in very low concentrations. Therefore, only low concentrations of SARS-CoV-2 are to be expected even in raw wastewater due to dilution effects. SARS-CoV-2 is closely related to the virus that caused the SARS epidemic in 2002/2003. Even during the SARS epidemic of 2002/2003, only a few cases of infectious corona virus were detected in hospital wastewater. In wastewater treatment plants, the concentrations of viruses present in the wastewater are reduced by a further 1-2 powers of ten. In addition, SARS coronavirus-2 is an enveloped virus which, in contrast to the unenveloped viruses (e.g. noroviruses) found in wastewater, cannot survive in wastewater for a longer period of time".

The complete notification of the DWA can be found here (german only): https://de.dwa.de/de/gefaehrdung-durch-coronavirus.html
as download (PDF) here (german only): Danger_by_Coronavirus.pdf



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