本研究以石化廢水為實驗對象，以混凝沉澱為前處理，再配合掃流微過濾技術來降低廢水中的有機物質及其毒性。本研究分成二個階段，前一階段以混凝沉澱瓶杯實驗，決定最佳的混凝劑種類及其劑量與pH值。實驗發現多元氯化鋁(PAC)與三氯化鐵有較好的濁度去除率，可高達98.6%，但COD之去除率均有限，且因濁度之去除率並不與COD之去除率成正比，故推斷混凝沉澱後之上層液中尚含有大量之有機質。本研究的第二個階段進行薄膜過濾實驗，探討在不同薄膜孔徑之過濾條件下對混凝--薄膜過濾程序效益之影響。研究結果顯示，混凝及薄膜過濾操作後可改善累積流量，降低濁度及去除部分之COD，廢水之毒性亦可大幅降低；而毒性測試結果顯示廢水之生物毒性與有機物質之含量有相當之關聯性。 Petrochemical industry wastewater, Coagulants, Membrane Microfiltration, Microtox tests)
In this study, coagulation with microfiltration membrane systems was evaluated for the treatment of petrochemical industry wastewater. Three different coagulants, i.e. polyaluminium chloride (PAC), ferric chloride and ferrous sulfate, were used in this study. Turbidity, COD, quantity of permeates and Microtox toxicity was used as the parameters for the assessment. There were two phases of this study, the first phase was to decide the optimum dosage of coagulant for coagulation, and the second phase was to evaluate the efficacy of the coagulation-microfiltration system under the different operating modes. As for coagulation, the results showed that an exceptionally high removal efficiency of turbidity was obtained when PAC was used as the coagulant. However, the removal of COD was not effective by PAC. Similar results were observed for ferric chloride while the lowest removal efficiencies of turbidity and COD appeared when ferrous sulfate was used. As for coagulation-microfiltration system, two positive results were obtained from this study; the first one showed that the operation of settling after coagulation could enhance the removal efficiencies of turbidity and COD, especially on COD removal. The second one, from the results of Microtox test, showed that the toxicity referred as TU50 could approximately be reduced about 50% by this process.
