The ultimate goal is that almost all sewage treatment plants install these coronavirus early warning systems in order to monitor the spread of Covid-19.
“It would be the first line of testing,” said microbiologist Hauke Harms, one of the leaders of the study. “You would start with our measurements and then you would know where to go to find the reasons. Normally it’s a hospital, or I don’t know, a factory where you have an outbreak. And then you should test people.”
The concept seems simple enough: wastewater contains the remains of the human stool virus. If these concentrations suddenly jumped, the sewers would detect it and warn the authorities to take action and start targeted tests of the area in question.
Sewage plants in the city area of Leipzig in eastern Germany, which can serve populations of between 100.00 and 600,000 people, are among those taking part in the study.
“If it were possible to get an idea of the concentration of coronavirus in wastewater, we can calculate the number of infected people in Leipzig and this would be very interesting in coronavirus strategies,” said Dr. Ulrich Meyer, technical director of the Leipzig aqueduct.
But it’s actually not that simple. In the main sewer system in Leipzig, samples are extracted every two minutes while wastewater flows for 24 hours a day.
Helmholtz scientists recognize that finding a small amount of genetic material (or RNA) from the virus in a giant river of waste is a monumental task.
“We have a high and high volume of waste water and it is a challenge to find traces of the virus in waste water,” said Rene Kallies, a virologist who works on the project. “So we have liters and we have to scale them down to microliters to get enough for RNA extraction and that’s the challenge.”
However, scientists say they can detect a wave of Covid’s tracks within a day and pass that information on to local authorities.
Another challenge, the scientists say, is the current low number of new infections in Germany, which makes it even more difficult to find the virus and means that a single infected person could distort the test results.
“You may have heard of these super-spreaders and there are also super-writers, for example. People who expel much more viruses than others and obviously this gives you a wrong idea of the number of infected people,” said Harms.
Germany was supported as an example of a country that successfully rejected the worst devastations of the virus. As of Friday, he had reported over 182,000 Covid-19 cases with around 8,400 deaths, significantly lower than in other European countries.
Tracing the virus in excrement is not new and German researchers are not alone in working to try to use waste water as an alarm system. In February, scientists from the Dutch KWR Water Research Institute discovered the virus in six sewage plants in the country, including one serving Schipol’s main international airport. KWR claimed to have developed a method for monitoring the presence of the virus in wastewater and that testing wastewater has clear benefits.
“Considering that tests on individuals require individual tests, tests in wastewater can provide a first indication of contamination within an entire population,” said KWR on its website.
German researchers believe that wastewater testing will be one of the factors in a network of measures to detect outbreaks.
But they acknowledge that there are still problems to be resolved, although they claim to be confident that the system will be up and running in the second half of 2020, in time to help contain a possible second wave of coronaviruses.
“I think we can offer something before the next wave,” said Harms, referring to a functioning detection system that can be used by states and sewage systems. “So if the next wave comes in the fall or early winter or so, then we should have something.”