本研究建構一好氧沉浸式薄膜生物反應槽（Submerged Aerobic Membrane Bioreactor，SAMBR）處理化糞池出流水，實驗過程分為三階段，第一階段系統不排泥及不添加鹼度物質，第二階段添加碳酸氫鈉（500 ppm），第三階段添加碳酸鈉（500 ppm），第二及第三階段皆固定污泥停留時間（Sludge retention time，SRT）15天，固定水力停留時間（Hydraulic retention time，HRT）22小時，探討各項水質參數之去除效果，計算氮化物質量平衡及各水質參數之實際去除率。
本系統MLSS濃度於穩定後其範圍介於2000到3000 mg/L，COD去除效率穩定且高達95%，SS去除率高達99%以上，TOC去除率達83%。COD食微比介於0.05~ 0.45 kg COD/kg MLVSS-day之間，TOC食微比介於0.01~ 0.05 kg TOC/kg MLVSS-day之間； COD體積負荷介於0.1~0.3 kg COD/m3-day之間，TOC體積負荷最大值達0.2 kg TOC/m3-day。
氮系列百分比轉換方面，以第三階段（添加碳酸鈉500ppm）較佳，進流水氨氮與有機氮各占系統總氮量78%、21%，硝酸鹽氮0.64%，經硝化作用後，氨氮與有機氮占系統百分比0.2%、10%，硝酸鹽氮占系統86%，硝化作用明顯。研究結果顯示，在本系統中添加碳酸鈉鹼度對處理效率之提升，較添加碳酸氫鈉之結果為佳。
由本研究結果得知，MBR系統對於化糞池出流水，具有極佳之處理幼纂A可作為套裝化應用之參考，以提供水回收再利用之另依替代方案。 In this study, a bench scale submerged aerobic membrane bioreactor was constructed for the treatment of septic tank effluent. A long term experiment for 269 days was divided into 3 stages.
No sludge was withdrawn for stage 1. A SRT of 15 days was adopted for stage 2 and 3. Different kinds of alkalinity were employed for the evaluation of system performance. 500 mg/L of NaHCO3 was added for stage 2 and the same concentration of Na2CO3 was used for stages 3.
The results of this study showed that the MLSS concentration under the steady state was in the range of 2000 mg/L to 3000 mg/L, the removal efficiency of COD, SS and TOC was 95%, 99% and 83%, respectively. The F/M ratios of COD and TOC were in the range of 0.05 to 0.45 kg COD/kg MLVSS-day and 0.01 to 0.05 kg TOC/kg MLVSS-day. The COD volumetric loading of membrane tank was in the range of 0.1 to 0.3 kg COD/m3-day. The TOC volumetric loading of membrane tank was with a maximum of 0.2 kg TOC/m3-day.
The highest conversation of ammonia-nitrogen was found at stage 3. NO2─-N was non-detected in the influent at stage 3 and the percentages of NH4+-N, Org-N and NO3－-N was 78%, 21% and 0.64%, respectively. The results indicated that the nitrification was completely and the percentages of NH4+-N, Org-N and NO3－-N in effluent was 0.2%, 10% and 86%, respectively. The results also indicated that the addition of sodium carbonate for the alkalinity was better than the addition of sodium bicarbonate for the system performance.
This study illustrated that the post treatment of septic tank effluent using an 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 on-site treatment unit for the polishing of septic tank effluent.
