TREATMENT OF WASTE WATER OF SILICON WAFER POLISHING

摘要

PROBLEM TO BE SOLVED: To provide a rational treatment method for decreasing the drugs, etc. used heretofore in individual treatments and reducing the load of active carbon of succeeding steps by forming treated water contg. a thick waste liquid of polishing contg. a surfactant more than easily biodegradable org. matter at the time of treating the various waste polishing liquids or polishing waste water discharged from a semiconductor silicon wafer production process. ;SOLUTION: This treatment method for the waste water discharged from the semiconductor silicon production process 10 has a first stage for mixing the thick waste liquid of polishing contg. the org. surfactant discharged from the production process 10, the waste liquid mixture of ammonia-hydrogen peroxide discharged from the production process 10 and a ferrous salt under acidity, a second stage for mixing the treated water of the first stage and the dilute waste water of polishing contg. the suspended matter discharged from the production process 10, subjecting the mixture to pH regulation and flocculating and settling the ferrous salt included in the treated water of the first stage as iron hydroxide in a flocculating vessel 2 and a third stage for treating the treated water of the second stage with a biological treatment apparatus 4.;COPYRIGHT: (C)1999,JPO