About COVID-19 (Sewerage)

The city provides sewage samples to the University of Tokyo, a member of the COVID-19 Task Force of the Japan Society of Water Environment, and cooperates with the survey.

Results of the survey from the University of Tokyo (March 4, 2021)
〇 Period from May 11, Reiwa 2 to June 15, 2010 (water sampling once or twice a week)
　As a result of providing inflow sewage (20 samples) from two water reclamation centers in Yokohama, COVID-19 RNA was not detected.
〇 Period from July 1, 2010 to October 19, 2010 (water sampling once a week)
　As a result of providing inflow sewage (34 samples) from two water reclamation centers in Yokohama, COVID-19 RNA was detected in four samples. (Kanagawa Wastewater Treatment Plant: July 21, July 29, October 19, Tsuzuki Wastewater Treatment Plant: August 26)

The World Health Organization (WHO) provides provisional guidance ※As a result, the risk of infection from infected person feces is low, and there is no knowledge that it has been transmitted through sewers. In addition, the guidance has announced that the COVID-19 virus is less stable compared to known viruses with waterborne infectious diseases (such as norovirus), so it is considered that the risk of infection from the sewer is low.
※Provisional guidance on water, sanitation and waste management regarding the COVID-19 (COVID-19 virus)

The Ministry of Health, Labour and Welfare (MHLW) has stated that it is possible to inactivate COVID-19 in the process of general sewage treatment (pH7 to 8), which requires about 8 hours of residence."
Since the residence time of sewage treatment in Motoichi is about 8 hours, safety is considered to be ensured.
In addition, effluent and reclaimed water are chlorinated (addition of sodium hypochlorite solution), and ozone treatment with a higher disinfection effect is performed for murmuring water.

Although the risk of infection from the sewer is considered to be low, in order to ensure safety measures for those who work, wear gloves and masks that have been implemented before and wash hands after work according to the provisional guidance of the WHO We ask for thorough safety management such as disinfection.