NOVELTY - Anaerobic digestion of a raw feedstock containing raw organic solids, involves transferring a quantity of the feedstock into digestion tank (1); mixing and chopping the feedstock; holding the feedstock in digestion tank for partial microbial hydrolysis of the feedstock; drawing off a portion of the supernatant and transferring to digestion tank; collecting gases and transmitting the gasses to another digestion tank; maintaining the temperature of the supernatant at 24-35 degrees C; operating the digestion tank; and collecting and storing methane gas is produced.    USE - For anaerobic digestion of raw feedstock for producing the methane (claimed).    ADVANTAGE - The method is significantly simplifying the operational requirements, significantly increases the reliability, and significantly increase the organic degradation and methane gas production rates; provides reliable and profitable source of methane gas as a renewable energy source; reduces quantity and cost of pH control chemicals because pH control is only required in the smaller stage third tank; and increased rates of solids digestion in stage first, thus improves waste solids dewatering characteristics, and reduce odors and final disposal requirements and costs.    DETAILED DESCRIPTION - Anaerobic digestion of a raw feedstock containing raw organic solids, involves transferring a quantity of the feedstock into a first digestion tank (1); mixing and chopping the feedstock to reduce the size of the raw organic solids contained in the feedstock; holding the feedstock in the first digestion tank for a predetermined period of time to provide for at least partial microbial hydrolysis of the feedstock, where the feedstock has a pH of 5.5-6.5; ceasing the mixing of the feedstock and allowing the settling of solids from a supernatant; drawing off a portion of the supernatant from the first digestion tank and transferring the drawn off portion to a second digestion tank (5); collecting first gases from the first digestion tank and transmitting the first gasses to a third digestion tank; maintaining the temperature of the supernatant in the first digestion tank at 24-35 degrees C; operating the second digestion tank as an upflow fluidized bed reactor, the reactor having a top and a bottom, where supernatant pumped from the first digestion tank enters the second digestion tank at the bottom and exits the second digestion tank at the top as filtered supernatant, where the feedstock has a pH of 5.5-6.5; adjusting the upflow velocity of the supernatant moving through the second digestion tank to minimize suspended and colloidal solids in the filtered supernatant; drawing off a second portion of the filtered supernatant from the second digestion tank; collecting second gases from the second digestion tank and transmitting the second gases to the third digestion tank; maintaining the temperature of the supernatant in the second digestion tank at 24-35 degrees C; heating the filtered supernatant to a mesophilic temperature or a thermophilic temperature; adjusting the pH of the filtered supernatant to maintain a pH of 7.8-8.5 in the third digestion tank; transferring the second portion of filtered supernatant to the third digestion tank; operating the third digestion tank as a packed bed reactor (10) having an upper portion containing a second digester media, where the second digester media is selected from low angle anaerobic digester media and enhanced surface area media, and a lower portion containing high angle anaerobic digester media, the filtered supernatant flowing through the lower portion then through the upper portion; injecting the first and second gasses into the third digestion tank upper portion; discharging filtered effluent from the third digestion tank; and collecting and storing methane gas produced in the third digestion tank.    DESCRIPTION OF DRAWING(S) - The figure shows view of three stages, multiple phase anaerobic digestion system.    First digestion tank (1)    Second digestion tank (5)    Bed reactor (10)    Upper conduit (11)    Lower media bed portion (16)