Abstract: A system is provided for separating waste water or solution into a permea solution and a concentrated solution by feeding the waste water or solution to a reverse osmosis apparatus using a membrane.A chemical pretreating apparatus is provided to prevent hard scales contained in the waste water or solution from precipitation during the concentration in the reverse osmosis apparatus using the membrane. An apparatus for charging sponge balls is further provided to mechanically remove suspended solids and other suspended matters, that is, soft scales when deposited on the surface of membrane. The sponge balls are desirably recyclically used.