利用薄膜生物反應槽為化糞池後處理單元之研究

Application of Membrane Bioreactor as a Post Unit for the Treatment of Septic Tank Effluent

本研究在實驗室架構一沉浸式薄膜生物反應槽(SMBR)，並以校園內之化糞池出流水做為研究對象。由於傳統化糞池常因設計不良或管理不善，往往無法有效處理，導致放流水中還是含有大量的有機物存在。本研究之目的是模擬薄膜生物反應槽為後處理設施改善化糞池放流水之水質。研究方式是以固定參數HRT 6.48小時，水槽體積12L，再以不同鹼度及操作條件作以分析探討。研究結果顯示，本系統之進流水鹼度不足，需額外添加，以提供硝化作用，在四個階段中，以第四階段處理效果為最佳，TCOD去除率最高為96%，DCOD則是90%，惟本系統對於色度去除之有待加強。研究結果得知本系統對於改善化糞池出流水水質，具有極佳之處理功效。本研究之結果叫作為實廠應用之參考，並提供水回收再利用之另一替代方案。

In this study the performances of a laboratory scale membrane bioreactor (MBR) was examined for the aerobic treatment of septic tank effluent. The reactor was with a working volume of 12 L. in continuous operation the suction pump was stopped for 1 minute to allow membrane relaxation after each 5 minutes of filtration to give an average hydraulic retention time (HRT) of 6.48 hours. No sludge was withdrawn during the stage 1 and 2 operations. The SRT of stage 3 and stage 4 was 10 and 20 days respectively. 250 mg/L of NaHCO3 was added for stage 1 and 500 mg/L for stages 2, 3 and 4. The highest removal efficiency of TCOD (total COD), DCOD (dissolved COD) was 96% and 90%, respectively. This study showed that the treatment of septic tank effluent using the laboratory scale aerobic membrane bioreactor was feasible and effective. The results obtained from this study could be applied to the field works and considered as an alternative of household treatment unit for the advance purification of septic tank effluent.