Generally, the floors of buildings and shops are regularly cleaned by cleaning companies. As a specific task, a strong alkaline detergent is applied to the floor, rub it with a machine to collect wastewater. The wastewater collected at this time is strong alkaline (pH 10-11), BOD, It also contains a lot of pollutants such as SS. Usually, these wastewater is not treated at all and is discarded as it is, but is there any problem in view of emission standards such as the Sewerage Law?

About water flowing into the sewer, water quality standard is established by the Sewerage Law or the Yokohama City Sewerage Ordinance. This standard covers the concentration of wastewater at the outlet to the sewer, and if it exceeds the standard, you will need to establish abatement facility or take necessary measures. Therefore, regardless of the amount of wastewater discharged to sewage, please follow the standards of more than 5 and less than 9 when draining to sewage.

Regarding BOD and SS, water quality standards are applied to business establishments with a daily wastewater volume of 2,000 cubic meters or more, so most of the business establishments are exempt from water quality regulations.