NOVELTY - Reducing multi-heavy metal in biogas liquid involves anaerobic fermentation of biogas naturally partition into sedimentation tank (3), where sedimentation tank clapboard set with four level between each level clapboard and pool wall set with grids in fill one level, grid set with bottom sludge, where hydraulic retention time of sedimentation tank inner clapboard is 4-6 hours, slag baffle on sedimentation tank bottom part discharge liquid by sedimentation tank clapboard entering into buffering lifting tank, where first-stage adsorbent is modified of vinegar residue and algae residue.    USE - For reducing multi-heavy metal in biogas liquid (claimed).    ADVANTAGE - The method is simple, and no secondary pollution, a green and cost-effective combination of technology, effectively reduced slurry in a variety of heavy metals, to solve the problem of agricultural biogas security, while effectively slow release of nutrients supplements to avoid biogas loss of nutrients to meet the needs of the soil fertility.    DETAILED DESCRIPTION - Reducing multi-heavy metal in biogas liquid involves anaerobic fermentation of biogas naturally partition into sedimentation tank (3), where sedimentation tank clapboard set with four level between each level clapboard and the pool wall set with grids in fill one level, grid set with the bottom sludge, the hydraulic retention time of the sedimentation tank inner clapboard is 4-6 hours, slag baffle on the sedimentation tank bottom part a discharge liquid by sedimentation tank clapboard entering into buffering lifting tank, where first-stage adsorbent is modified of vinegar residue and algae residue combination; biogas inner buffering lifting tank (5) through lifting pump (6) entering into irrigation main, main trench fill inner absorption bag of 5-10 level, absorbing inner bag fill the second level, while in the field channel entrance at least set with one absorption bag, each bag adsorption dry weight is 10 kg, where the second level is the carbide modified of bagasse.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of Reducing multi-heavy metal in biogas liquid.    Water inlet (1)    Multi-grade baffle plate (2)    Sedimentation tank (3)    Sludge (4)    Buffering lifting tank (5)    Lift pump (6)    Main channel (8)