Activated carbon treatment has been widely adopted due to the strengthening of the effluent standard and legal revision, as well as instruction to switch from discharge into rivers to discharge into sewerage areas and necessity for compliance with environmental programs under ISO 14000. In conventional activated carbon treatment systems, activated carbon is firmly fixed in the upper layer, and it is replaced with new activated carbon although activated carbon in the lower layer is still usable. In addition, since the surface of activated carbon is coated with suspended substances, internal absorption performance cannot be fully utilized, and thus early replacement is necessary. Therefore, it has been very difficult to make best use of the capacity of activated carbon. We solved these problems and developed the “ACTIVATED CARBON SIPHON TANK,” which is an innovative activated carbon absorption facility that largely extends the life of activated carbon. ACTIVATED CARBON SIPHON TANKs can significantly reduce the cost for replacing activated carbon and maintenance costs. It also reduces the amount of energy consumed in reactivating carbon or producing new carbon, thereby largely contributing to the conservation of the global environment.