NOVELTY - The self sustained bio-digester comprises a biological treatment component, a chemical treatment component, a non-biodegradable materials elimination component, a socket (13) present in a middle of a first chamber for removal of residual solids and small non-biodegradable materials and for cleaning, an another socket (14) present in a middle of a sixth chamber for removal of the settled residual sludge, and two inbuilt stainless steel support hooks placed on either sides of the bio-digester for fixing the bio-digester. The biological treatment component comprises housing.    USE - The self sustained bio-digester is useful for onboard degradation of human waste for single toilet in public carriers such as train, bus, boat and aeroplane.    ADVANTAGE - The self sustained bio-digester is capable of anaerobically, economically, continuously and safely onboard degrading the human waste at ambient temperature with high efficiency and reduced energy consumption and without foul smelling compounds and pathogenic microorganisms in an environmentally friendly manner, is easy to use and maintain, prevents the entry of non-biodegradable materials such as water bottles, tea cups and food packaging materials, and has higher cell mass for enhanced fermentation and better tolerance of bacteria for adverse environmental conditions and to have better baffling.    DETAILED DESCRIPTION - The self sustained bio-digester comprises a biological treatment component, a chemical treatment component, a non-biodegradable materials elimination component, a socket (13) present in a middle of a first chamber for removal of residual solids and small non-biodegradable materials and for cleaning, another socket (14) present in a middle of a sixth chamber for removal of the settled residual sludge, and two inbuilt stainless steel support hooks placed on either sides of the bio-digester for fixing the bio-digester. The biological treatment component comprises housing. The housing has six chambers separated by partitions providing an anaerobic chamber having a long path and time for biological treatment. A chlorination chamber is fixed outside the housing, and has a hinged cap for stacking chlorine tablets inside a retrievable cylinder allowing only one tablet to come in contact with an effluent. A junction box (10): is placed at a top of the bio-digester housing; connects the bio-digester with a toilet for excluding non-biodegradable materials; comprises steel rods fixed at an angle of 30 degrees from a horizontal for sliding the non-biodegradable material out of the box through a guide (12) projected out of box and optionally curved pipe connecting an inlet pipe (7) and chamber; and has vertical rods through out a hole at a junction of the inlet pipe. The bio-digester has an immobilization matrix in a form of polyvinyl chloride on partitions and bottom and sides for attachment of bacteria to prevent washout. A series of pipes connects the chambers and units in the bio-digester. The pipe in the first chamber is covered by a sieve throughout a depth and height of the first chamber. The waste from a second chamber flows through a slit to chamber third, fourth and fifth. The waste enters from the fifth chamber to the sixth chamber through the pipe as arranged in the first chamber, and leaves the chlorinator through a first pipe. The fermented waste goes out of sixth chamber through a pipe ' 8 ' at the right side of sixth chamber wall and enters to chlorinator. The first and second pipes open in the chlorinator at almost the same height and opposite to each other. A slider valve is provided at a junction of the curved pipe and the inlet pipe. The submerged inlet pipes prevent the entry of foul smelling gases from the head space to the toilet. A window present on a side of fermentation chamber removes sludge, and helps in maintenance.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a bio-digester.    Inlet pipe (7)    Rectangular box (10)    Guide (12)    Socket (13)    Another socket. (14)