The paper is entitled covid-19: mitigating transmission viawateweater building systems. The authors team is from the Institute of sustainable architectural design of Herr Watt University in Edinburgh and the company solidsense in Glasgow, UK. The corresponding author is Michael Gormley, the chief director of the water academy, water supply and sanitation expert of Herr Watt University, and architectural electrical service engineer.
This paper also discusses some measures to reduce the transmission of virus through the waste water pipeline system, including paying close attention to the functionality of the water seal device in the U-shaped elbow of household appliances, and dealing with the cracks or leaks in the pipeline in time.
Chinas novel coronavirus pneumonia meeting is the key to the new crown pneumonia strategy in the afternoon of March 25th. The leaders of the National Health Protection Committee and the Chinese Academy of engineering, Zhong Nan Shan, attended the video conference on the prevention of pneumonia in the Central African countries in March 25th.
Since the outbreak of SARS, Michael Gormley and his team have been studying the mechanism of virus cross transmission, how to improve the design of wastewater treatment system and innovation of system monitoring. The team has confirmed that wastewater pipeline system can become a pathogen repository.
From the beginning of the design, the wastewater pipeline system means the presence of a large number of pathogenic microorganisms, and in some cases, it has the potential to promote the air transmission of new coronavirus. The authors wrote at the beginning of the article.
Wastewater pipeline system is likely to be the accomplice of coronavirus transmission. Previously, in 2003, who issued a final report on the spread of SARS virus in a residential building in Hong Kong.
342 SARS cases were confirmed in the 50 storey building, 42 of them died. The report points out that the defect of wastewater pipeline system is a kind of transmission mode of virus in the building, which promotes the transmission of virus droplets in the hollow U-bend in the bathroom.
The bathroom exhaust fan further helps with this air transmission, as the exhaust fan draws the polluted air into the room.
In 2017, the researchers conducted an experiment on a full-scale two-layer wastewater pipeline test device, in which they used model organisms (Pseudomonas putida) to represent the pathogens washed into the wastewater system.
The experimental results show that the living bacteria spread between the rooms on different floors of the building, and through the air flow of the system, the settlement of the droplets will lead to the pollution of the system and the inner surface of the room.
Previously, the researchers also proposed the causes of defects in the wastewater pipeline system, and proposed a basic qualitative risk assessment for the spread of diseases in buildings. They found that an important factor related to the risk of virus transmission is that the waste water pipeline system connects all parts of the building, so there is the possibility that the polluted air can move unimpeded in the building.
The team also found that the short-term outward leakage of polluted air in the sewage pipeline system would lead to cross contamination.
The researchers pointed out that in view of the speed of covid-19 transmission, it is of great significance to study the potential role of wastewater pipeline system in virus transmission. The interconnection of wastewater pipeline network and the sensitivity of the system to overuse, underuse, high temperature and highly concentrated infected people all cause peoples concerns about self isolation and the safety of using hospital wards as isolation areas.
The authors explain that highly concentrated infected people will increase the virus load in the system, which will lead to higher risk of disease transmission; self isolation may lead to more infected people in the building, and then lead to overuse of the system; because of the interaction of the whole system, the use of hospital wards as isolation area will also bring greater risk.
In this paper, the authors suggest the following measures to ensure that virus transmission through the wastewater pipeline system is minimized:
First, dont ignore the smell that bathroom, kitchen or toilet cant explain;
Second, ensure that all water related appliances in the bathroom and kitchen are equipped with U-bends with good functions;
Third, in order to ensure the functionality of the water seal device in the U-bend of household appliances, all faucets should be turned on twice a day (in the morning and at night) for at least 5 seconds, and special attention should be paid to the floor drain of bathroom and humid room;
Fourth, if the waste water pipe with electrical appliances seems to be disconnected or open, please seal it immediately (for example, cover the end with elastic rubber gloves; or use plastic bags and some adhesive tapes to ensure that the bag has no holes)
If any crack or leakage is found in the pipeline, seal it with tape or glue;
Finally, for large or high-rise buildings, it is necessary to continuously monitor the performance of the whole wastewater system.
The researchers pointed out that the possibility of a large number of virus load in the wastewater pipeline system (and then the main sewer system), coupled with the potential of air transmission after virus atomization, requires us to consider the wastewater pipeline system as a potential transmission way of covid-19. Following the above recommendations will help to minimize the risk of transmission.
According to the authors, the interconnection of wastewater pipeline network will lead to the risk of transmission of new coronavirus in buildings and even between buildings, which is of particular concern in high-risk transmission environments such as hospitals and medical facilities.