Let's introduce the "mechanism" that cleans the dirty water flushed from toilets and kitchens.
- Sewage first enters the anaerobic filter tank. In the anaerobic filter bed tank, solids (suspended matter) in the sewage are caught on the plastic filter media and most of them are removed. Also, anaerobic microorganisms (microorganisms that work well in the absence of oxygen) attached to the surface of the filter media eat and remove contaminants dissolved in the sewage.
- In the contact aeration tank, there are various types of aerobic microorganisms (microorganisms that work well in the presence of oxygen). With the help of oxygen in the air sent from the blower, they eat and remove the dirt dissolved in the water.
- The clumps of microorganisms (sludge) that have grown by eating the dirt components are removed in the sedimentation tank, and the clean supernatant water is disinfected with chlorine before being discharged.
- In the process of cleaning sewage, dirt components and solids remain in the tank as sludge and accumulate. In order to stably maintain the work of johkasou, it is necessary to create an environment where microorganisms can work vigorously, such as operation and maintenance, replenish disinfectant, and clean the tank to remove sludge.
There are various structures of johkasou, such as a sedimetation tank without a filter medium instead of an anaerobic filter bed tank, and a moving bed tank instead of a contact aeration tank in which the contact material moves with the water in the tank. The working and processing functions are almost the same.