A Study in the use of Fixed-Film Bioreactor and Electro-Fenton Methods in Acrylonitrile Wastewater Treatment

[[abstract]]NBR合成橡膠製程廢水特性含有丙烯晴(AN)、界面活性劑及其它添加物成份複雜，製程中以回收AN汽提塔底部廢水(CODt=2515mg/L，AN=221mg/L)最難處理，而類似性質之廢水Wyatt and Knowles(1995) 研究指出係生物難分解之廢水。 本研究利用固定式生物膜反應器及電解還原Fenton法進行探討，研究結果發現此股廢水以過濾水稀釋2倍及3倍以固定式生物膜反應器在水力停留時間10小時實驗結果AN去除率達98%以上，COD平均僅去除66%(65%~67%)，以電解還原Fenton法進行電解氧化實驗先去除COD 50%以上(電解氧化之中間產物為甲酸、乙酸、草酸)，再串接固定式生物膜反應器實驗在水力停留時間10小時下COD平均去除81%(79%~85%)，此與過濾水稀釋2倍及3倍以固定式生物膜反應器實驗COD平均僅去除66%比較，去除效率顯然大幅改善。[[abstract]]The process wastewater of an NBR synthetic rubber manufacturing plant is complicated in that it contains acrylonitrile, surfactants and other components. In process, the effluents from the bottom of the acrylonitrile recovery stripping column (CODt=2515mg/L, AN=221mg/L) are difficult to biodegrade, a development confirmed by a similar study by Wyatt and Knowles (1995). This study takes advantage of Fixed-Film Bioreactor (FFR) and Electro-Fenton Methods in conducting the investigation. The effluents were diluted 2x and 3x in an FFR at Hydraulic Retention Time (HRT) for 10 hours. The results showed that the acrylonitrile removal efficiency was more than 98% but COD removal was only 66% (65%~ 67%). Another experiment involved the application of the Electro-Fenton method to remove COD at above 50% initially (The intermediate compounds including formate, acetate, oxalate during the reaction) and then series to FFR at HRT for 10 hours. The results showed that the COD removal efficiency was 81%(79%~85%). Comparing the results of experiments between FFR and Electro-Fenton with FFR in series, it is clear that the latter has better efficiency, especially when it comes to COD removal