NOVELTY - An anaerobic fermentation raw materials impurity removing method involves regulating livestock and poultry excrements in a mixing pool to reach fermenting concentration. Fermentation raw materials (1) are stirred in a mixing pool uniformly. Inorganic impurities (4) with large density are settled at bottom of the mixing pool. The inorganic impurities are scraped into the hopper. The scrapped inorganic impurities are conveyed to a drying bed. Uniformly-mixed feed liquid is screened. The screened liquid is fed into a feeding tank (13). The inorganic impurities in the liquid are removed.    USE - Method for removing impurities from anaerobic fermentation raw materials during livestock and poultry excrement recycling process.    ADVANTAGE - The method enables preventing abrasion and blockage of equipment and pipeline caused by the impurities in the livestock and poultry excrements, and providing easiness in forming scummings, so that operation management level and recycling efficiency of the livestock and poultry excrement recycling treatment project can be improved.    DETAILED DESCRIPTION - An anaerobic fermentation raw materials impurity removing method involves regulating livestock and poultry excrements in a mixing pool to reach fermenting concentration. Fermentation raw materials (1) are stirred in a mixing pool uniformly. Inorganic impurities (4) with large density are settled at bottom of the mixing pool during stirring process. A sand collecting hopper is arranged at bottom (5) of the mixing pool. The inorganic impurities are scraped into the hopper by a sand scarping machine (6), after finishing feeding. The scrapped inorganic impurities are conveyed to a drying bed through a spiral conveyer (7). The uniformly-mixed feed liquid is fed into a vibrating screen (10) through an underflow pump (9) for screening. The impurities that are easy to cause pipeline blockage and form scummings in a fermenting pool are discharged on a fixed screen (12). The feed liquid screened by the vibrating screen and the sewage filtered by the fixed screen are fed into a feeding tank (13) through a feeding pump (14). A cyclone sand remover is arranged on a pipeline through which the feed liquid and the sewage enter a fermentation tank (16). The inorganic impurities in the feed liquid are removed.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view illustrating a method for removing impurities from anaerobic fermentation raw materials during livestock and poultry excrement recycling process.    Fermentation raw materials (1)    Inorganic impurities (4)    Bottom of the mixing pool (5)    Sand scarping machine (6)    Spiral conveyer (7)    Underflow pump (9)    Vibrating screen (10)    Fixed screen (12)    Feeding tank (13)    Feeding pump (14)    Fermentation tank (16)