The Optimization for Grinding Wafer Wastewater Treatment

• Main Authors: Bor-Wei Wuu, 伍柏韋
• Other Authors: Chien-Kuei Chang
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/90941636153035506629

碩士 === 國立高雄應用科技大學 === 化學工程與材料工程系 === 99 === The pollutant particle size in semiconductor has gradually become smaller with the precision of the manufacturing process. The wastewater from wafer grinding process could generate large nano-scaled polluted particles. Great amount of coagulant was always added to precipitate the tiny particles. However, the volume of sludge will increase dramatically. Thus, how to decrease the sludge volume and increase the ratio of discharging wastewater has become a big challenge in wastewater treatment. In this work, Taguchi experimental design method was used to investigate the treatment efficiency of following four systems in wafer grinding wastewater. 1. chemical coagulation, 2. cation polymer flocculant, 3. magnetic seeding aggregation, 4. combination of chemical coagulation and magnetic seeding aggregation. The results revealed that the best treatment system was combination of chemical coagulation and magnetic seeding aggregation. The optimal conditions could be found in PAC 1.6 g, magnetite 0.1 g, polymer of cation 0.01 g, pH 9, agitation rate 200 rpm (1 min) and 30 rpm (3 min), magnetic field 2400 Gauss, and the compaction time 10 min. The turbidity of wastewater could be decreased from 3500 NTU to 1.12 NTU, indicating 99 % turbidity was removed. The volume of sludge could be reduced to only 116 cm3 every 800 cm3 wastewater. The performance is much better than the used method in some semiconductor industry in Kaohsiung.