含TMAH廢水生物處理及生物毒性減量評估

Abstract

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，除了將氨氮納入二階段管制外，並將生物急毒性移至水污染防治措施予以規範。目前高科技產業製程化學品繁多，其中又以TMAH廣泛地被使用在半導體與光電等高科技產業中。TMAH為具有毒性之有機銨化合物，經過生物處理降解後會釋出氨氮，產生後續污染之問題。因此建立完整廢水處理毒性減量之技術與放流水毒性鑑定將成為高科技廠刻不容緩的議題之一。 本研究除了提供建立水蚤實驗室時，所需相關生物特性及品質管制參數外，分別就氨氮、TMAH與亞硝酸氮的單一化合物與各別混合物進行水蚤生物毒性測試實驗。實驗結果證實，當氨氮、TMAH與亞硝酸濃度增加時，水蚤生物毒性有顯著之提升，其三者的線性回歸R2分別為0.9445、0.9965與0.9842，均具有高相關性。而綜合毒性評估的部分，當氨氮、亞硝酸氮及TMAH三種化合物相互混合後，其水蚤生物毒性都具有加成性的增加，產生協同作用之現象。此外，本研究應用厭氧系統降解TMAH有機氨再經厭氧氨氧化（anaerobic ammonia oxidation, anammox）系統將氨氮轉化成氮氣，做為降低生物毒性的方式，依實驗結果顯示TMAH經UASB處理後轉化率可達95%以上，幾乎可完全分解成氨氮。將UASB氨氮的出流水經anammox處理後氨氮轉化率可達90%，生物毒性也大幅降低，顯示經由UASB與anammox技術結合可有效去除TMAH及氨氮，同時減輕生物急毒性，當面對未來氨氨與TMAH管制法規趨嚴，提供一解決途徑。

Conscious of environmental protection was high during this decade. EPA of Taiwan regulated the discharge regulation of opto-electronics, sewer system of science parks and semiconductor manufacturing industries. Ammonia nitrogen and toxicity were regulated for these high-tech industries. There are many chemicals applied in these high-tech industries, especially for TMAH. TMAH is a toxic organic nitrogen compound. After biodegradation, TMAH is degraded to ammonia nitrogen and released to the water body. Thus, toxicity reduction and toxicity evaluation are two major issues for high-tech industries to obey the new regulation of ammonia nitrogen and toxicity. Establishment of Cyclops lab test including the Cyclops characteristics as well as parameters of quality accuracy and quality control was one of the major goals of this study. Ammonia, TMAH and nitrite compounds were found out their toxicity. Meanwhile, mixtures of each compound were also evaluated.The result indicated that the higher ammonia concentration, the higher toxicity phenomenon was found with R2 of 0.9445. TMAH and nitrite compounds had the same result with ammonia with R2 of 0.9965 and 0.9842, respectively.Toxicity evaluation of the mixture of ammonia, TMAH and nitrite indicated that the toxicity was raised with multiple effects and belonged to synergistic effect. An anaerobic treatment process (UASB) was applied to degrade TMAH compound. The ammonia released from TMAH degradation was then treated by an anaerobic ammonia oxidation (anammox)process from ammonia to nitrogen gas. The result indicated that the removal efficiency of TMAH compound was higher than 95 % in the UASB and most of the TMAH was degraded to ammonia. The ammonia removal efficiency of the anammox process was about 90 %. After treatment of the UASB and anammox processes, toxicity of TMAH compound was lower down. The result indicated that anaerobic process including UASB and anammox was one of the suitable biological techonologies for the TMAH and ammonia removal of high-tech industries