The city's civil engineering and public health departments are participating in an EU-funded pilot project of the UKB Institute for Hygiene and Public Health. The aim is to find out whether Corona viruses can be detected in wastewater from the city's sewage treatment plant.
Bonn. The city's civil engineering and public health departments are participating in an EU-funded pilot project of the UKB Institute for Hygiene and Public Health. The aim is to find out whether Corona viruses can be detected in wastewater from the city's sewage treatment plant.
40,000 cubic litres of grey water flow in streams every day through a basin located in the middle of a large grey concrete building below the grey concrete pillars of the A565. The municipal sewage treatment plant in Bonn-Castell appears visually somewhat less enlightening than findings that the Bonn University Hospital (UKB) is hoping for in a current study. In cooperation with the health and civil engineering departments, the Institute for Hygiene and Public Health of the UKB is now examining the wastewater of the city of Bonn, which is treated in the sewage treatment plant on Salierweg.
On the one hand, an increased occurrence of coronaviruses could be detected. On the other hand, the health department hopes to be able to predict infectious diseases in general. It would be conceivable to set up a wastewater monitoring system for early warnings, says Liane Marciano of the health department at a press meeting on Tuesday morning. "We have been working with testing so far in detecting Covid infections, so in that respect this new method is very exciting. We hope this sewage monitoring will detect incidences and also different Corona variants."
The advantage of wastewater testing: the samples come up all by themselves
These detections could then also be linked to neighbourhoods and socio-economic factors or vaccination status prevailing there. What is particularly exciting for Nico Mutters, the director of the Hygiene Institute of the University Hospital, is that there are two different catchment areas in the Salierweg sewage treatment plant: on the one hand, those of several city hospitals, and on the other hand, the rest of the city area without clinical influence. This is a "unique opportunity" to "correlate Corona incidences and hospitalisation rates with wastewater testing", says Mutters.
But isn't this way of collecting samples much slower than simple Corona smears? The excreta must first reach the sewage system, then the sewage treatment plant and finally the UKB. Correct, replies Mutters. Wastewater monitoring, however, is easier to carry out on a broad scale, because the samples come naturally by the hectolitre and all by themselves. Moreover, the testing is passive. People usually come to a testing centre for a reason. Symptom-free people much less often. Twice a week, sewage samples are taken at the sewage treatment plant, transported to the UKB and examined there. It takes five to six hours to inspect the samples there.
Unique research project for the sewage treatment plant
In the wastewater, symptom-free diseases can thus also be detected and thus also predicted. "Then you can take targeted measures. For example, by taking targeted swabs again in city districts with increased positive detections," adds Mutters. The disadvantage of the tests is that the results cannot be assigned to specific streets. The EU is funding the project for this year with 60,000 euros. However, this money is only for material and not for personnel. The Hygiene Institute pays for this out of its own pocket "because we consider the project important", says Mutters.
"Wastewater has a negative connotation. It smells unpleasant. I am all the more pleased that we can now make an important contribution to research with our sewage treatment plant," says Director Achim Höcherl. This cooperation project is very interesting, as it already took place in a smaller form in October 2020. Otherwise, the project is a novelty for the Bonn sewage treatment plants; influenza viruses or similar have not yet been searched for in Bonn's wastewater.
Protection of staff from infectious wastewater must be guaranteed
The protection of the staff who take the samples has high priority, says head of the civil engineering office Peter Esch. Initially, there was concern that the aerosols in the wastewater could infect them with Covid. But this is countered by the fact that the employees are already used to a high standard of protection, since all kinds of germs are on the way in the wastewater, such as influenza or hepatitis. FFP2 masks, face protection and showering before leaving the hazardous area are standard for maintenance workers.
Drug use in a city can also be reflected in wastewater, for example through cocaine residues in excreta, says sewage plant manager Höcherl. Such investigations, however, have not yet been undertaken in Bonn.
Original text: Simun Sustic
Translation: Mareike Graepel