| Summary: | 碩士 === 國立臺灣科技大學 === 化學工程系 === 90 === The major objective of this study was to investigate treatment of polishing wastewaters from semiconductor manufacturer. Coagulation/flocculation and ultrafiltration were utilized in treating wastewaters from chemical mechanical polishing (CMP) and back-side grinding (BG) wastewater. Experimental results indicated that polyaluminum chloride (PAC) could remove turbidity effectively. Coagulation-flocculation mechanisms were discussed based on floc size distribution and zeta potential.
Effects of molecular weight cut-off of membrane, operation pressure and crossflow velocity were investigated in ultrafiltration experiments. Mechanisms of different kinds of wastewater in ultrafiltration were assessed and modeled. Ultrafiltration of BG wastewater and CMP wastewater in sequence resulted in a dynamic membrane ultrafiltration phenomenon. The performance of dynamic ultrafiltration depended on the operation conditions significantly. Flux decreased with increasing dynamic layer thickness, yet, with lower decline rate of flux. As a conclusion, filtrate was examined on the feasibility of recycle and reuse in semiconductor manufacturer.
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