NOVELTY - An anaerobic digester comprises a tubular digester hull (10) assembled from sections containing injection pump (12) to move both influent feedstock into a digester hull and digested feedstock out of the hull; a one-way valve (13) to prevent feedstock from flowing back through inlet; a cross-sectional area that allows entrapment of biogas; gas outlets; a gas regulation valve; and an elevated effluent outlet.    USE - For producing biogas useful for generating fuel through biological process on e.g. small and mid-sized farms that use a scrape system for manure management.    ADVANTAGE - The digester achieves an economy of scale through mass-production and shipment to the purchasing farm; can be assembled without the placement of permanent structures without the need for custom engineering and/or construction companies; and is simple and cost-effective to operate and requires mechanical components need run only periodically or part-time. The digester can be easily cleared of accumulated sediments in a short period, with little human resource; is self-pressurizing, and passively maintains pressure in an open vessel that supports a continuous flow of feedstocks; can accept feedstocks with greater than 8% and less than 18% solids. The digester can be disassembled and relocated and therefore be classified as a moveable asset. The tubular digester permits the mass production and shipping of an anaerobic digester, the assembly of a digester without the need for engineering or heavy construction specialists, and direct use of feedstock slurries with high solids contents. The digester allows the digester to operate with a high degree of energy efficiency; permits the disassembly of the digester for resale, liquidation, or reconfiguration; and permits a variety of digester configurations that can be tailored to a range of operation sizes, needs and conditions. The elevated digester's outlet precludes the need for a pump to move effluent materials towards the next step of effluent feedstock processing.    DETAILED DESCRIPTION - An anaerobic digester comprises an assembly of straight and tapered tubular sections to form a tubular digester hull (10) with tapered ends (11); an injection pump (12), manual or mechanized, to move both influent feedstock into the digester hull and the digested feedstock out of the digester hull; a one-way valve (13), built into the structure of the injection pump or placed at the entry of the digester to prevent the feedstock from flowing back through the inlet; a cross-sectional structure that allows the entrapment of biogas in the tubular region between the tapered ends of the digester; at least one gas outlet, optionally connected through a manifold (14), that permit withdrawal of biogas from the digester hull; a gas regulator or valve (24) for controlling release of biogas from the digester; an elevated effluent outlet for the entrapment of gas within the digester hull and to allow the inflow of fresh feedstock to control the outflow of effluent feedstock; and a further elevated effluent outlet for passive pressurization of the biogas entrapped within the digester hull. The feedstock can be biologically acted upon to produce biogas that can be used directly and/or stored for later use.    An INDEPENDENT CLAIM is included for a structure for inoculation of organisms into a moving particular-laden feedstock comprising structural members arranged individually, or as an array, within digester or bioreactor, a cross-sectional shape for each member that supports the growth of microbial biofilm, members to interact with a significant percentage of the cross-sectional area of feedstock flow, members with an overall surface area that does not necessarily support enough biofilm to significantly contribute to feedstock processing, and an attachment mechanism that locks members into position within the digester, Where the flow of feedstock across member leads to removal by abrasion or natural release of organisms from biofilm growing on that member and these organisms enter the feedstock as inoculum to further colonize particulate surfaces within the feedstock.    DESCRIPTION OF DRAWING(S) - The figure shows the multi-hull anaerobic digester.    tubular digester hull (10)    tapered ends (11)    injection pump (12)    one-way valve (13)    manifold (14)    gas regulator or valve. (24)