solid waste , for example source separated organics or commercial and industrial waste or both , are treated by first pressurizing the waste against a screen to produce a solids fraction and a liquid fraction . the liquid fraction can be treated in an anaerobic digester . the solids fraction is pulverized or milled , for example with a hammer mill , preferably after being diluted . the pulverized or milled waste is separated again to provide a second solids faction and a second liquid fraction . the liquid fraction can be treated in an anaerobic digester . the solids fraction is primarily inert and can be landfilled , preferably after being washed .