NOVELTY - A gasification-power-generation system has a gasifier which heats biomass and generates biogas, a scrubber, a gas-washing-water processing apparatus (8) which process gas-washing water, and an engine electric-power generating apparatus. The gas-washing-water processing apparatus has a water-storage tank (41), a acidic adjustment tank (42) comprising an apparatus (52) which adjust gas-washing water to acidic, an apparatus (53) which injects microbubbles and a removal apparatus (54), and an alkaline adjustment tank (43).    USE - Gasification-power-generation system.    ADVANTAGE - The foreign material mixed in gas-washing water in gasification-power-generation system is efficiently removed, and the collected foreign materials are recycled.    DETAILED DESCRIPTION - A gasification-power-generation system has a gasifier which heats biomass and generates biogas, a scrubber which washes biomass, a gas-washing-water processing apparatus which process gas-washing water, and an engine electric-power generating apparatus comprising a gas engine which uses biogas as fuel and electric power generating apparatus which is driven with the gas engine. The gas-washing-water processing apparatus has a water-storage tank which stores gas-washing water, a acidic adjustment tank comprising an apparatus which adjust gas-washing water to acidic, an apparatus which injects microbubbles and a removal apparatus (54) which removes solid substance which floats on water surface with microbubbles, and an alkaline adjustment tank comprising an apparatus (82) which adjusts gas-washing water to alkalinity, an apparatus (83) which injects microbubbles and a removal apparatus (84) which removes solid substance which floats on water surface with microbubbles. The solid substance removed by the acidic adjustment tank and alkaline adjustment tank is burned in gasifier. The gas component vaporized by the acidic adjustment tank and alkaline adjustment tank is recycled as fuel of gas engine. An INDEPENDENT CLAIM is included for processing of gas-washing water.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic view of the gas-washing-water processing apparatus.    Gas-washing-water processing apparatus (8)    Water-storage tank (41)    Acidic adjustment tank (42)    Alkaline adjustment tank (43)    Apparatuses (52,82)    Apparatuses which inject microbubbles (53,83)    Removal apparatus (54,84)