After the primary sedimentation tank, the water goes into an enclosed rotating bio-reactor, with adequate surface space and water pressure; the aerobic bacteria which consume organic matter can get full contact with the sewage. FSCI can achieve a high bio-adhesion (1000m2/m3 and above), which is 2-3 times more than other products. FSCI provides active in-house ventilation which does not need to additional aeration system. The bio-belt has a self-cleaning function, the water under biological treatment can automatically go back water inlet of the entire system, which can prevent the sludge from the primary rotting and breeding mosquitoes and flies, it can adjust the sewage flow to meet peak load and fast biological reproduction as well.