Start-up strategy of anaerobic treatment for TMAH wastewater in a semiconductor fabrication plant

• Main Authors: Yu, Tin-shiuh, 俞庭旭
• Other Authors: Huang, Chih-Pin
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/tubnr5

碩士 === 國立交通大學 === 工學院永續環境科技學程 === 104 === Tetramethyl ammonium hydroxide (TMAH) is often applied as a developer in semiconductor and liquid crystal display (LCD) industrial processes. Because environmental protection consciousness surged upward in recent years, EPA of Taiwan tightened the discharge requirements of opto-electronics, sewer system of science parks and semiconductor manufacturing industries. Hsinchu Science Park (HSP) Bureau also announced the two-stage TMAH limits for the effluent in the HSP sewer system. TMAH containing wastewater from LCD factory in Taiwan was generally degraded by anaerobic treatment, however in IC industry, simply treated it by physical and chemical method. In this study, this is the first case for IC industry with tresatment of TMAH containing wastewater by anaerobic approach. In this study, average TMAH concentration in the influent was 1600 mg/L with ranging between 1200~1800 mg/L during the testing period. UASB granular sludge from a food factory was seeded into the bioreactor by using stage load promotion strategy. After starting 90 days to reach the end of testing, the removal efficiency of TMAH were between 95% and 98%. Moreover, it found that part of the developer exhibited biological inhibition effect in the anaerobic sludge, suggesting, for engineering design, an anaerobic toxicity assay test (ATA Test) for each developer is necessary in order to improve the probability of successful biological domestication and to reduce risk of biological inhibition. For environmental protection, it also helps to the control of raw materials, chemical substances of difficult to be decomposed preferentially excluded, reduce secondary pollution and environmental impact. This case confirms that the anaerobic process is effective and feasible for the treatment of TMAH containing wastewater in IC industry.