積體電路製造業含TMAH廢水厭氧生物處理之起動策略研究

Abstract

積體電路、LCD生產製程常使用氫氧化四甲基銨(TMAH)為顯影劑，由於近年來環保意識高漲，因此環保署增訂光電、科學園區污水下水道系統和晶圓製造業的放流水標準，新竹科學園區管理局也修改科學工業園區污水處理及下水道使用管理辦法與相關水質標準，將TMAH納入二階段管制。而相關含TMAH排放廢水在台灣已有多個LCD廠使用厭氧技術處理包含顯影劑等綜合廢水，但在積體電路業多使用物化方式處理，本研究以積體電路製造業TMAH製程廢水為唯一污染源進行厭氧處理工程，實為首例。 本研究設計厭氧進流水TMAH濃度為1,600 mg/L，試車期間TMAH濃度主要介於1,200~1,800 mg/L之間，以食品廠UASB顆粒汙泥為植種來源，採用階段式負荷提升策略進行試車，起動後90天達到全量運轉，全量運轉後TMAH去除率介於95~98%間；此外於研究中發現，部份顯影劑對厭氧污泥具有生物抑制作用，建議於工程設計前可針對各顯影劑，進行厭氧毒性測試(Anaerobic Toxicity Assay, ATA Test)，提高日後生物馴養成功的機率，及降低生物抑制風險。對於環境保護而言，也有助於原物料管控，將不易分解之化學物質優先排除，減少二次污染與環境衝擊。由本案例證實，積體電路製造業TMAH製程廢水以厭氧技術進行處理是一個可行、有效的方法。

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.