NOVELTY - The assembly has two circular tanks (2,3) that are connected with two inspection chambers (IC) (1) by two pipes (22), for collecting human waste and kitchen waste from two ICs. Inverted tanks (6,7) are inserted in circular tanks and are supported by a pair of bar with cement slurry, for collecting gas generated by circular tanks. The biogas generated from circular tanks is filtered and then transferred for cooking purpose through flexible gas pipe (18), while making assembly as eco-friendly. The assembly is constructed three feet above the ground for protecting from flood.    USE - Eco-friendly septic tank and biogas assembly for use in flood prone areas.    ADVANTAGE - Since the biogas produced from eco-friendly septic tank is collected, filtered and used for cooking purposes, the emission of harmful greenhouse gas can be reduced. The treatment of organic solid waste is done in closed intact tanks, so that the generation of odor is reduced, and thus the organic matter is recycled to generate nutrient rich manure. The collection and filtration of gases are done in septic tank, so that the need of separate space for the plant can be avoided. The efficiency of the eco-friendly septic tank and biogas assembly can be improved. The water pollution can be minimized. The manufacturing cost of the assembly can be reduced. The slurry generated from the septic tank can be effectively utilized for garden or flushing. The gas generated from the septic tank is not hazardous and does not cause any explosion as in liquid petroleum gas (LPG) gases.    DETAILED DESCRIPTION - Two circular tanks are linked by a connection unit (14). A square tank (4) is connected to second circular tank by an outlet, for collecting the waste effluents from circular tanks.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic diagram of eco-friendly septic tank and biogas assembly.    IC (1)    Circular tanks (2,3)    Square tank (4)    Inverted tanks (6,7)    Connection unit (14)    Flexible gas pipe (18)    Pipe (22)