将下列段落翻译 Waste biomasses are secondary biomass, as they are derived from primary biomass like trees, vegetables, meat during the different stages of their production or use.MSW is an important source of waste biomass, and much of it comes from renewables like food scraps, lawn clippings, leaves, and papers .Nonrenewable components of MSW like plastics, glass, and metals are not considered biomass. The combustible part of MSW is at times separated and sold as refuse derived fuel (RDF).Sewage sludge that contains human excreta, fat, grease, and food wastes is an important biomass source. Another waste is produced in sawmills during the production of lumber from wood.