ACIDIC WASTEWATER TREATMENT METHOD FOR TREATING ACID MINE DRAINAGE USING CALCIUM HYDROXIDE IN RAW WATER INFLOW TANK, NEUTRALIZATION TANK AND SEDIMENTATION TANK AND RETURNING SETTLED SLUDGE TO NEUTRALIZATION TANK TO REUSE SETTLED SLUDGE

摘要

PURPOSE: To provide a method for treating acidic wastewater by returning high concentration sludge, the method for reducing absolute concentration of pollution sources in acid mine drainage before discharging the acid mine drainage, returning settled sludge to a neutralization and reusing the settled sludge to reduce costs of chemicals and facility operation and reduce moisture content of sludge. CONSTITUTION: A method for treating acidic wastewater by returning high concentration sludge comprises a process of treating acidic wastewater in a neutralization tank(7), a raw water inflow tank(8) and a sedimentation tank(11) such that the acidic wastewater is neutralized by injecting chemicals into the neutralization tank, wherein barium salt or calcium hydroxide that is pre-melted in a calcium hydroxide melting facility(1) as the chemicals for neutralizing the acidic wastewater is injected into the neutralization tank, and wherein high concentration settled sludge generated in the sedimentation tank is returned to the neutralization tank such that a sludge return ratio is maintained to a range of 10 to 50%.