With a sharp change in water quality and resulting bulking, stable wastewater treatment could not be achieved.

After installation of a rotating biological contactor, filamentous bacteria increased on the surface of disks, and a large volume of sludge on the surface of the disk with good deposits in the deposition tank

Effluent standard value for sewage effluent is BOD 200mg/L, but stable operation at the water value was difficult.

By rotating biological contactor method, treated water quality could be freely determined by designing the load. Stable treatment was realized with sewage effluent standard value (BOD 200mg/L).

Although the amount of wastewater emitted enhanced with the increased production, since there was no space to increase wastewater treatment equipment, the treated water quality degraded.

The rotating biological contactor was installed by building a platform in the parking lot.