A method of treating fluid body waste material includes, separating the material into factions, in which the solids content of one faction is increased substantially relative to the originating waste material, while a second faction has an increased liquid content. Material is pumped from a storage facility, passing through a first screen. Retained solid material is removed from the screen while partially cleansed liquid passes to a holding tank. The partially cleansed liquid is then passed through one or more cyclone separators. The output containing larger particles is passed to a second, finer screen with further removal of solids. A further output from the cyclone separator, of substantially clean liquid is fed partly back into the holding tank and partly back into the storage facility. Agitation of the waste material in the storage facility can be provided.