NOVELTY - Early production of methane rich biogas, carried out in a digester (200) comprising container (10), feeding system (20), gas collection pipe, rubber stopper, cathode (50), anode (60), encapsulated tube and overflow releasing pipe (80), comprises: filling the container with slurry of organic matter; accelerating the methane production by accelerators; stabilizing the digester at 30-37 degrees C plus minus 2 degrees C and at 8-8.5 pH in the anaerobic condition; activating the stabilized digester; normalizing the digester; and withdrawing the slurry from the digester upon gas production.    USE - The process is useful for production of methane rich biogas from organic matter.    ADVANTAGE - The process: provides methane rich biogas in early stage by semi-continous process; accelerates anaerobic methane formation at ambient temperature and thus does not require pretreatment to animal manure; can be carried out without the supervision of skilled operators; efficient in accelerating and maintaining the growth of slow growing methanogenic microbial community in a large cell mass; easy to operate, low-cost and operable at commercial as well as at field trials; is not affected by higher concentration of volatile fatty acids; and adaptable for the treatment of polluted natural and manmade ecosystems to self remediate and to produce biogas containing 85-90% of the methane.    DETAILED DESCRIPTION - Process for an early production of methane rich biogas, carried out in a digester (200) in an anaerobic condition, the digester having a container (10), a feeding system (20), a gas collection pipe, a rubber stopper, a cathode (50), an anode (60), an encapsulated tube and an overflow releasing pipe, comprises: filling the container of the digester with a slurry of an organic matter; accelerating the methane production by supplementing varying concentration of accelerators to the digester; stabilizing the digester by maintaining a temperature of 30-37 degrees C plus minus 2 degrees C and at 8-8.5 pH in the anaerobic condition for a predefined period; activating the stabilized digester by adding optimum dosage of accelerators while feeding the digester with the organic slurry and keeping the digester in a controlled condition till the highest output of gas obtained; normalizing the activated digester by feeding the slurry of organic matter in predefined quantity without any addition of accelerator; and withdrawing the slurry from the digester upon optimum gas production, where, when the digester is connected in a bi-phase, the biogas produced in a first digester is passed to a slurry of a second activated and normalized digester through the gas collection pipe and there after the second digester produces methane by reducing the carbon dioxide in the biogas of the first digester.    DESCRIPTION OF DRAWING(S) - The figure shows a digester for an early production of a methane rich biogas.    Container (10)    Feeding system (20)    Cathode (50)    Anode (60)    Digester (200)