NOVELTY - Anaerobically digesting dilute animal waste with biogas production involves: conveying dilute animal waste through waste inlets in a flexible bladder; maintaining the dilute animal waste in the flexible bladder at an average ambient temperature of greater than or equal to 65degreesF for a period of time for digestion of the dilute animal waste; and removing digester effluent from the bladder through digester effluent outlets in the bladder. The method further involves recovering the biogas produced in the bladder, and removing solid waste from the bladder through sludge access ports in the bladder.    USE - Used for anaerobically digesting dilute animal waste with biogas production and recovering biogas (claimed).    ADVANTAGE - The process inexpensively, simply, reliably, and effectively treats animal waste without energy expenditure and little capital expense, minimizing pollution typically caused by animal waste. The process simply, reliably, and inexpensively treats animal waste with biogas production and recovery in warm climates where minimum temperatures are ca. greater than or equal to 65degreesF. The process helps to control air and water pollution from livestock waste, protects public health and offers an opportunity for the waste to be used as a renewable energy resource. The sizing process permits biological stabilization of ambient temperature anaerobic digesters treating dilute animal wastes and other dilute high strength wastes in regions that lie between 35degrees north and south latitudes. The digester may be factory fabricated and field installed making it particularly well suited for the small farm having limited resources.    DETAILED DESCRIPTION - Anaerobically digesting dilute animal waste with biogas production involves: conveying dilute animal waste through waste inlets in a flexible bladder; maintaining the dilute animal waste in the flexible bladder at an average ambient temperature of greater than or equal to 65degreesF for a period of time for digestion of the dilute animal waste; and removing digester effluent from the flexible bladder through digester effluent outlets in the flexible bladder. The process further involves recovering the biogas produced within the flexible bladder; and removing solid waste from the flexible bladder through sludge access ports in the flexible bladder. The substantially flexible bladder is constructed of a reinforced geo-membrane material.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of an anaerobic digester system having a flexible bladder.