WASTEWATER TREATMENT METHOD IN SEMICONDUCTOR MANUFACTURING PROCESS UTILIZING PURE WATER MAKING WASTE LIQUID

摘要

PROBLEM TO BE SOLVED: To reduce the cost of a neutralizing agent adapted to the waste liquid of a semiconductor wafer manufacturing process required heretofore and to realize the stable operation of a flocculation and sedimentation process.;SOLUTION: Waste alkali and waste acid discharged at the time of regeneration of an ion exchange resin in a pure water making process are independently stored and wastewaters discharged from the respective processes up to manufacture of a semiconductor wafer are respectively grouped to obtain alkali wastewater and acid watewater wherein a suspended substance is present, alkali wastewater or alkali or acid wastewater wherein no suspended substance is present to be stored in corresponding neutralization treatment tanks and the waste alkali or waste acid discharged at the time of regeneration of the ion exchange resin is supplied to the respective grouped neutralization treatment tanks to neutralize the wastewater, and the wastewater wherein the suspended substance is present is charged in a flocculation tank and the waste alkali or waste acid discharged at the time of regeneration of the ion exchange resin is appropriately charged in the flocculation tank to flocculate the suspended substance while pH is adjusted.;COPYRIGHT: (C)2001,JPO