To stably and efficiently execute anaerobic treatment by preventing methane fermentation reaction obstruction by methanol in evaporated condensate water and also preventing the outflow of sludge from a reaction vessel, when introducing the evaporated condensate water discharged in a pulp manufacturing process to the reaction vessel holding granule sludge and executing the anaerobic treatment.
When introducing the evaporated condensate water through an adjustment vessel to the reaction vessel together with a part of treated water and executing the anaerobic treatment, the flow rate of the evaporated condensate water is adjusted so that the soluble CODCr concentration of water to be introduced to the reaction vessel becomes 1,500 mg/L or lower, and the flow rate of the water to be introduced to the reaction vessel is set so that a rising flow speed in the reaction vessel becomes 2 to 5 m/h. By fixing the amount of the water to be introduced to the reaction vessel (at a predetermined value) and then adjusting the flow rate of the evaporated condensate water so that the soluble CODCr concentration of the water to be introduced to the reaction vessel becomes a predetermined value or lower, the methane fermentation reaction obstruction is prevented, and the outflow of the sludge from the reaction vessel is prevented as well.
OGIYA HIROSHI
KIYOKAWA TOSHIHIRO
TOKUTOMI TAKAAKI
KURITA WATER IND LTD
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