Covid-19 is mainly transmitted by droplets, by coughing or sneezing. However, the risk of contamination by wastewater cannot be excluded. Since the discovery of the disease, observations on infected patients have shown that their intestines are contaminated and that the virus is present in human waste. Of course, a virus cannot develop outside of a living cell. But: it can be protected from destruction for a long time if it is surrounded by organic substances. According to the WHO, viruses in biofilms and sewage sludge can survive up to a year.
Accordingly, it can be assumed that the wastewater beneath our cities would be contaminated with the corona virus and could also be seen in sewage treatment plants. Even worse: due to the dilapidated condition of the sewer systems, it cannot be ruled out that the contaminated liquids can penetrate other ecosystems.
It should be noted that the risk in Europe is relatively low. But in countries where hygienic standards are less developed, epidemics usually break out through contamination of the running water. By defecation outdoors or even in watercourses, pathogens spread rapidly.
The solution is obvious: Similar to social isolating and elbow cough, it is a matter of not transferring the virus to other environments, isolating it. Decentralized toilet systems like WeCo toilets could help here. These toilets are ecological, water-saving and, above all, not connected to any sewer. Wastewater treatment is “on site” without large energy consumption and most of the waste are recycled into resource. When it comes to decentralized and ecological toilets, many people first think of dry toilets, which of course represent the cheapest low tech solution. However, the comfort and hygiene of the dry toilet without water rinsing is rather limited. Even more problematic, the main issue of dry toilets is that the virus and pathogen remain untreated for several months, sometimes years; which spreads the diseases everywhere. One should recall that our flushing water toilets and sewerage in cities have been invented during the late 19th century in London than Paris, to meet with the modern hygiene requirement and avoid the pandemic like cholera that killed thousands of people in 1871 in Paris and is still killing in emerging countries due to the fast growing urbanization.
In the spirit of sustainable development and innovation, research groups worldwide are working on concepts for water-saving, decentralized public toilets that directly recycle wastewater, sewage sludge, faeces and urine. The innovative company WeCo from France has taken a big step. The WeCo team has been developing since 2014 a virus-killing mobile toilet system, partnering initially with Caltech. The toilet system does not require a sewer connection, no water inlet and still offers toilets and urinals with water flushing. The wastewater is retreated in a closed cycle. This patented solution transforms heavily contaminated wastewater through biological treatment and electrolysis into clear water with swimming water quality, without exposure to bacteria or chemicals. This water is treated and then reused for flushing the toilet. The process of electrolytic water disinfection uses electrical current to create a means of disinfection directly in the water through electrochemical conversion. With the help of salt dissolved in water, electrolysis technology creates chlorine, a powerful disinfectant. This in-situ formation of disinfectant based on chlorine creates a lasting disinfectant effect, killing the bacteria and virus in the waste water. Though, chlorine cannot be used in the biological treatment of faecal sludge, a solution is under development to destroy the pathogens in the faecal sludge.
Applied worldwide, the decentralized WeCo electrolysis toilets could save millions of tons of drinking water and also improve hygiene and prevent the spread of diseases through contaminated water.
 Water, sanitation, hygiene, and waste management for the COVID-19 virus. Interim guidance WHO and UNICEF 19 March 2020