06. Little floor space 07. No sludge bulking and sludge clogged when long-termed operation 08. Biology on the carriers comes into being long food chain, so the sludge settles easily and production of sludge is 40 to 80 per cent less than A.S. 09. Efficiency is 30 to 50 per cent higher than A.S. while the operation cost decreasing 30% at least 10. Could be directly dropped into aerobic basin, anaerobic basin, and anoxic basin, no replacing within 50 years 11. Not being restricted by pool shape, it can be used in all kinds of pools. The carrier can be fully mixed with water trends in reaction pool, which enabling full use of whole pool and without any corer not being utilized.