Abstract: In a circulation treatment system and method for treating a fountain solution the amounts of BOD, COD, n-hexane and SS are reduced in the fountain solution to recycle the fountain solution without draining it off. Circulation passages are connected to a vessel of a dampening section of an offset rotary press via communication passages, and circulate a fountain solution by introducing the fountain solution in the vessel from an introducing port and discharging the fountain solution from a discharging port. In the course of the circulation passages is a line pump for forcibly circulating the fountain solution, a potential absorption filtering device using an absorbing effect of a zeta potential, and an activated carbon filtering device using an absorbing effect of activated carbon.