Relationship between Potassium Permanganate Consumption and Total Organic Carbon in Bath Water in Public Bathhouses and Similar Facilities

Abstract

Since the Ministry of Health, Labor and Welfare of Japan announced hygiene management guidelines for public baths in 2019, many local governments have revised their regulations on organic substances in bath water from potassium permanganate (KMnO₄) consumption of 25 mg L^-1 or less to the total organic carbon (TOC) of 8 mg L^-1 or less, in principle. The change in these values was 0.32 times. In Osaka City, the number of facilities that exceed the TOC standard has tended to increase after the revision of the regulations, so the relationship between KMnO₄ consumption and TOC was examined. As a result, the relation of TOC = 0.456 KMnO₄ in 38 facilities where inorganic disinfectant was used for bath water was determined in a survey of 47 facilities, and the coefficient of KMnO₄ was significantly larger than 0.32. This study in Osaka City showed that the new TOC standard for bath water is stricter than the former KMnO₄ standard.