利用延長曝氣法處理ABS廢水之成效研究

Performance of Extended Aeration Process for the Treatment of ABS Wastewater

本研究以延長曝氣法（Extended aeration process）處理實廠ABS樹脂廢水，系統控制條件SRT（Sludge retention time,SRT）為30天、曝氣控制5 L／min，主要探討其不同水力停留時間（hydraulic retention time,HRT）為1、1.5及2天控制下，處理系統對於化學需氧量（Chemical oxygen demand,COD）、生化需氧量（Biochemical oxygen demand,BOD5）、濁度（Turbidity）之處理效能，以及生物槽內的微生物生長情況，並且進一步討論各HRT控制下的變化狀態。研究結果指出，延長曝氣法在HRT為2天時，係為最佳操作條件，其生物槽內SS濃度範圍3200~4100 mg／L，而COD去除率為91%、BOD5去除率為92%、濁度去除率約90%。而當HRT縮短至1.5天及1天時，雖可提高系統內SS的增長，但其污泥的VSS／SS比值性質趨於無機性，當HRT操作為1天時，出流水濁度去除不良，且呈現多次的污泥洗出的現象。由研究結果顯示，在固定反應槽及沉澱槽體積、溫度、曝氣量的條件下，HRT的縮短，雖可提高SS濃度，但其VSS／SS值並無法保持穩定，且HRT的縮短會影響生物槽內的膠羽特性，對於沉澱槽的固液分離效能有顯著的不利影響，且探討其處理效能時，要監測觀察其出流水品質、生物槽內微生物生長狀態以及沉澱池的固液分離效果，才是完整的處理效能層面之探討。

In this study, a laboratory scale extended aeration process was used for the treatment of ABS （Acrylonitrile-Butadiene-Styrene） wastewater. SRT （sludge retention time） was 30 days and aeration rate was controlled at 5 L／min. The purpose of this study was to know the performances of this extended aeration process for the removal of COD, BOD5 and turbidity under the HRT （hydraulic retention time） conditions of 1、1.5 and 2days, respectively. The results showed that the optimal HRT was 2 days for this system. Under this HRT condition, the concentration of MLSS in the reactor was in the range of 3200 to 4100 mg／L. In addition, the removal of COD, BOD5 and turbidity was 91%, 92% and 90%, respectively. Lower HRT values showed higher SS values in the reactor. However, lower VSS／SS ratios and lower turbidity removals were obtained in the condition of short HRT.