NOVELTY - The feed anaerobic digester system comprises a first single stage anaerobic reactor (SD reactor) for treating a solid waste stream, a second single-stage anaerobic reactor (AFR reactor) for treating soluble components in waste water separated from solid waste stream, and a conduit connecting the SD reactor to the AFR reactor. The SD reactor comprises a cross-flow baffle. The cross-flow baffle comprises an elongate body including side walls and a top section that combined together to form an inverted V-shaped transverse cross section.    USE - The feed anaerobic digester system is useful for converting degradable feedstock solid waste into useful materials, where: the solid waste is carbonaceous organic waste including sewage sludge, forestry waste, food waste, agricultural waste, municipal waste, yard/garden waste (all claimed) and/or woody wastes such as wood chips; the useful material is methane, hydrogen and carbon dioxide and compost such as nutrient-rich digestate that is used as fertilizer; the yard/garden waste is leaves, grass clippings, yard trimming waste, perennial and annual plant materials and tree and shrub branches; the municipal waste is food wastes, hair, plastics, cardboard, paper, sewage, thickened sludge and miscellaneous organic and inorganic wastes from residential, commercial and institutional sources; and the agricultural waste is plant and/or animal wastes such as animal bedding, fur, sawdust, biosolids, foliage, straw, husks, fruit, vegetables and manure.    ADVANTAGE - The feed anaerobic digester system continuously converts degradable solid waste feedstock into useful materials in an efficient manner with excellent yield and without foaming.    DETAILED DESCRIPTION - The feed anaerobic digester system comprises a first single stage anaerobic reactor (SD reactor) for treating a solid waste stream, a second single-stage anaerobic reactor (AFR reactor) for treating soluble components in waste water separated from solid waste stream, and a conduit connecting the SD reactor to the AFR reactor. The SD reactor comprises a cross-flow baffle. The cross-flow baffle comprises an elongate body including side walls and a top section that combined together to form an inverted V-shaped transverse cross section. The inverted substantially V-shaped transverse cross section partially bounds a collection channel for gas produced in the SD reactor. The side walls comprise a permeable material. The permeable material is a mesh material having a pore size that is dependent on solid material present in the reactor and the desired flow rates of the waste water and/or waste stream, and comprises metal, ceramic, polymer materials, rubber, cloth, hair and/or plastic. The mesh material has a pore size up to 250 mu m. The channel injects and/or withdraws liquid to and/or from the side walls via a fluid pump. The solid waste stream is 20-35% of total solid waste. The SD and/or AFR reactor comprises a port for collecting gas produced in the reactors. The solid waste stream and/or the SD reactor and/or the AFR reactor comprises a bulking agent. The bulking agent comprises coal, stones, rocks, metal objects, gravel, plastic materials, yard trimming waste, cardboard, expanded clay, wood chips, sawdust, animal bedding, biosolids and hair, and is compatible with a solid waste stream. The solid waste stream is raw feed. The cross-flow baffle is provided in the SD reactor and/or AFR reactor. The digester system further comprises a controlling unit for controlling the temperature of a reactor. The controlling unit comprises a solar water heater, a gas-powered water heater, a steam generator, a heat exchanger and/or a heater or a heat generator. The SD reactor further comprises a sealed entry and a sealed egress. The sealed egress is present at the bottom of the SD reactor. The sealed entry and/or the sealed egress comprises a rotary valve, a staged valve, a rotary lobe pump and/or other positive displacement pump. The sealed entry and/or the sealed egress is located at a top, a bottom, a side or sides of the SD reactor. The AFR reactor comprises a media material capable of supporting anaerobic bacteria. The media material comprises rubber, plastic, wood, or metal. The media material is a semi-rigid, high-density polyethylene plastic mesh sheet having a mesh size of 1x 1 or 2x 2 inches. The media material comprises rock, activated carbon, expanded clay, tire chips, fabrics, coal or stone. The SD and/or the AFR reactor produces gas. An INDEPENDENT CLAIM is included for a method of converting degradable solid waste feedstock into useful materials.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of difference between a two-phase anaerobic digestion system and a two-stage sequential batch anaerobic composting system.