以水蚤評估半導體製程排水毒性來源

Abstract

環保署針對園區高科技產業廢水排放已開始執行生物毒性檢測，但管制期間各園區廠商以半導體廠無法達標的情況最為嚴重，共通問題為無脊椎類生物指標無法通過管制標準。因此本研究以某園區半導體實廠含高導電度及高水量之六股製程排水為對象，利用非脊椎類生物水蚤(Daphnia magna)毒性測定，分析並篩選源頭毒性來源。結果顯示各股排水單一毒性(TUa)由大到小為空調冷卻排水(114.11) >純水再生排水(17.45) >回收系統再生排水(13.33) >氟酸排水(9.73) >回收RO濃排水(9.23) >鹼性含氨排水(5.63)，均屬於極毒性(very toxic TUa > 5) ；其中以貢獻水量與毒性比例最高來源為空調冷卻排水，佔總放流毒性69.4%。結果亦顯示毒性與導電度相關性最高製程排水種類為純水再生、回收系統再生與氟酸排水。

EPA had executed the acute toxicity regulation for high-tech industry wastewater effluent in the science park. Semiconductor industry in the park has the most difficulty in the compliance of regulation, especially for the invertebrate test. Hence, this study adopted invertebrate acute toxicity test (i.e, Daphnia magna) for various effluent in a semiconductor fabrication plant. According to the conductivity or discharge of process effluents, six effluents were sampled and evaluated their contributions to the invertebrate acute toxicity. The results have shown that the toxicity (TUa) of these 6 effluents are ranked in air conditioning cooling effluent (114.11), RO reclaim effluent (17.45), recycling system reclaim effluent (13.33), waste hydrofluoric acid effluent (9.73), RO reclaim rejection effluent (9.23), and alkaline ammonia effluent (5.63). All these effluents are regarded as very toxic (ie,TUa>5). Among them, air conditioning cooling effluent is the major contributor, and it contributes 69.4% of the toxicity. In the meanwhile, the toxicity of RO reclaim effluent, recycling system reclaim effluent, and waste hydrofluoric acid effluent are highly relative to the conductivity.