以流體化床結晶技術處理半導體產業含氟廢水之案例探討

Case Study on the Treatment of Fluoride-Containing Wastewater of Semiconductor Manufacturer Using Fluidized-Bed Crystallization Technology

吳孟修(Meng-Hsiu Wu)

指導教授 ： 張迪惠 ； 白子易

朝陽科技大學/理工學院/環境工程與管理系/碩士(2012年)

摘要

摘要
半導體產業的含氟廢水主要是由於半導體製程的蝕刻和清洗製程中，經常使用大量的氫氟酸、有機溶劑及酸液所產生，而目前含氟廢水大多採用混凝沈澱法處理，本研究以流體化床節結晶技術(Fluidized Bed Crystallization, FBC)，期在不同的操作條件下改變不同進流氟負荷(kg .F/d)及加藥比（鈣氟比）來探討各操作參數影響放流水中氟離子濃度。
本研究案例處理之水量達150CMH，故設置A、B、C等三套流體化床結晶設備，每套流體化床結晶設備處理水量為50CMH，並以三套設備運轉後數據進行交叉比對，期能尋找最適運轉參數及加藥量。
研究結果顯示系統在依據設計參數進行運轉後，A系統F-去除率平均值為95%，B系統F-去除率平均值為94%，C系統F-去除率平均值為95%，三套系統平均F-去除效率可維持於95%。
A、B、C三套系統於Ca/F比與出流水F濃度呈現負相關性，代表Ca/F比越大時出流水F濃度越低； 而Ca/F比與出流水濁度呈現負相關性，代表Ca/F比越大時晶體結晶形成越佳；而F負荷與出流水濁度呈現正相關性，代表進流F負荷愈大時未完成結晶反應之氟化鈣也愈多。
研究結果顯示流體化床結晶系統在運作時，操作參數Ca/F > 0.5以上，即可維持出流水F < 15 mg/L以符合行政院環保署公告放流水標準及科學園區污水廠納管標準。

關鍵字

流體化床節結晶技術(FBC) ； 鈣氟比 ； 氟負荷 ； 含氟廢水

並列摘要

Abstract
The fluoride-containing wastewater of the semiconductor industry is mainly produced by the frequent use of the large amount of hydrofluoric acid, organic solvents and acid in the etching and cleaning of the semiconductor manufacturing process. At present, the fluoride-containing wastewater is mainly disposed by using the coagulation and sedimentation method. This study employed the FBC (Fluidized Bed Crystallization) method to change the inflow fluoride load (kg.F/d) and dosage (calcium/fluoride ratio) under different operating conditions to discuss the effects of various operating parameters on the concentration of fluoride ions in effluents.
The volume of wastewater for treatment in this study was up to 150CMH. Therefore, three sets of fluidized bed crystallization equipment of A, B, C were used for respectively processing 50 CMH. This study conducted cross-matching of the operating data of the three sets of equipment, expecting to find out the optimum operating parameters and dosage.
The results showed that, after the operation of the system according to the design parameters, the average F- removal rate of System A is 95%, the average F- removal rate of System B is 94%, and the average F- removal rate of System C is 95% the average F- removal rate of three systems can be maintained at 95%.
For all three systems A, B, and C, the Ca/F ratio and the effluent F concentration are positively correlated, indicating that the effluent F concentration will be lower in case of larger Ca/F ratio. The Ca/F ratio and effluent turbidity are negatively correlated, indicating that the crystallization will be better in case of larger Ca/F ratio. The F load and effluent turbidity are positively correlated, indicating that there is more un-crystallized calcium fluoride in case of larger F load.
Moreover, the effluent F < 15 mg/L can be maintained if the operating condition Ca/F > 0.5 is maintained in the operation of the fluidized bed crystallization system to comply with the effluent standards, as published by the Environmental Protection Agency, the Executive Yuan, as well as the standards of the sewage plants in the scientific industrial park.

並列關鍵字

FBC ； fluoride-containing wastewater ； fluoride load ； calcium/fluoride ratio

參考文獻

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