本研究係現場建構ㄧ沉浸式好氧薄膜生物反應系統(Submerged Aerated Membrane Bioreactor, SAMBR)之模廠，處理製藥業製程廢水。本系統於2005年12月啟動操作，啟動後76天內不排泥，第77天開始排泥時污泥停留時間為331天，系統平均水力停留時間為51小時，本研究探討各項水質參數之去除效果，並針對薄膜之積垢進行觀察與探討。
本研究針對系統排泥，進行兩階段之研究，第一階段為系統啟動至第76天，本階段內不排泥，此後開始排泥，為第二階段。實驗結果顯示，系統於第25天後穩定，至第76天排泥為止，好氧生物處理槽與好氧薄膜槽MLSS濃度各介於5.7~9.1 g/L與6.2~10.0 g/L，MLVSS濃度各為5.2~8.1 g/L與5.4~8.6 g/L，MLVSS/MLSS比值分別介於0.84~0.95與0.81~0.92；開始排泥17天後MLSS值再趨近於穩定，此階段好氧生物處理槽MLSS值12.3~15.2 g/L，好氧薄膜槽MLSS值於13.3~16.7 g/L之間。
BOD去除效率穩定且高達99.3%，COD與SS之去除率達95.9%與100%。系統中BOD體積負荷結果顯示，好氧生物處理槽介於0.068~4.617 kg BOD5/m3 day，好氧薄膜槽介於0.007~0.04 kg BOD5/m3 day；BOD食微比方面，好氧生物處理槽介於0.07~0.36 kg BOD5/kg MLVSS-day，好氧薄膜槽介於0.0005~0.0071 kg BOD5/kg MLVSS-day。系統COD體積負荷結果顯示，好氧生物處理槽介於0.099~6.844 kg COD/m3 day，好氧薄膜槽介於0.011~0.408 kg COD/m3 day；COD食微比方面，好氧生物處理槽介於0.014~0.65 kg COD/kg MLVSS-day，好氧薄膜槽介於0.003~0.079 kg COD/kg MLVSS-day；活性污泥比攝氧率(specific oxygen uptake rate；SOUR)結果顯示，好氧生物處理槽介於19~75 mg-O2/g MLVSS-hr，好氧薄膜槽介於30~81 mg-O2/g MLVSS-hr；放流水污泥密度指數(silt density index；SDI)值均在6.4以下，顯示放流水質良好。
本研究在系統操作至第22天與第96天針對薄膜進行人工清洗，於第102天針對薄膜進行一次膜管內部化學清洗。本研究利用掃描式電子顯微鏡(scanning electron microscope；SEM)掃描與X射線能量散佈分析儀(energy dispersive X-ray spectrometer；EDS)分析薄膜，結果顯示造成薄膜外部膜壁阻塞主要以生物膠體為主，其中ㄧ具薄膜外部膜壁附著之污染物質含有較多種類之重金屬元素，但薄膜內部膜壁重金屬元素種類較少，另一具薄膜內外膜壁之重金屬部分則與上述情形相反；由SEM與EDS結果研判薄膜外部膜壁附著之重金屬物質大部分被生物膠體所包覆，另一具薄膜顯示重金屬物質累積於薄膜內部膜壁，故造成兩組薄膜具有不同之透膜壓力與流通量。
本研究持續監測共計114天，於系統操作第219天再進行程序評估，系統操作與出流水質相當穩定。由研究結果得知，SAMBR系統對於製藥廢水水質之改善，具有極佳之處理幼纂A可作為製藥業製程廢水回收再利用之參考方案。 In this study, a pilot scale of submerged aerobic membrane bioreactor (SAMBR) system was installed for the treatment of pharmaceutical wastewater. The purposes of this study were to evaluate the treatment efficiency of pharmaceutical wastewater by SAMBR and the fouling phenomena of membrane was observed.
In this study, no sludge was withdrawn for 76 days during the initial period of operation. After day 77, sludge retention time (SRT) was set at 331 days and the average hydraulic retention time (HRT) is 51 hours. The results showed that a steady state of bio-system was obtained on day 25 after the sludge feeding. In the initial 76 days, the MLSS level of biological and membrane tanks was in the range of 5.7~9.1 g/L and 6.2~10.0 g/L, respectively. The MLVSS levels in the range of 5.2~8.1 g/L and 5.4~8.6 g/L were obtained for both of tanks. The MLVSS/MLSS ratios were also calculated both in the biological and membrane tanks. In the case of biological reactor, the MLVSS/MLSS ratio which in the range of 0.84~0.95 was obtained and 0.81~0.92 for membrane tank. The system was stable again on day 17 after sludge was withdrawn, at this sludge-withdraw stage, the MLSS level of biological tank was in the range of 5.7~9.1 g/L and 13.3~16.7 g/L for membrane tank.
BOD effluent was remarkably stable and with a highest removal efficiency of 99.3%. COD and SS removal was 95.9% and 100.0%, respectively. The results showed that the BOD volumetric loading of biological tank was in the range of 0.068~4.617 kg BOD5/m3 day and 0.007~0.04 kg BOD5/m3 day for membrane tank. The BOD F/M ratio of biological tank was in the range of 0.07~0.36 kg BOD5/kg MLVSS-day and 0.0005~0.0071 kg BOD5/kg MLVSS-day for membrane tank. COD volumetric loading of biological tank was in the range of 0.099~6.844 kg COD/m3 day and 0.011~0.408 kg COD/m3 day for membrane tank. COD F/M ratio of biological tank was in the range of 0.014~0.65 kg COD/ kg MLVSS-day and 0.003~0.079 kg COD/kg MLVSS-day for membrane tank. The results of specific oxygen uptake rate (SOUR) showed that the SOUR value of biological tank was in the range of 19~75 mg-O2/g MLVSS-hr and 30~81 mg-O2/g MLVSS-hr for membrane tank. The levels of silt density index (SDI) for all effluents were lower than 6.3 indicated the high quality of discharge.
Membrane modules were withdrawn for clogging removal on day 22 and day 96. Chemical cleaning was carried out on day 102 by inside-out type washing. The results of scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDS) demonstrated that the fouling of membrane outer surface was mainly due to microorganisms. The series fouling membrane showed that foulants of cation ions with high diversity species were observed on the outer surface and less cation ions were detected on the inner surface of membrane. However, the opposite results of cation distributions were obtained for the light fouling membrane. The results of SEM and EDS revealed that there were two mechanisms of membrane fouling in this study, cations accumulation by microorganisms on the outer surface or the deposition of cations on the inner surface of membrane, resulted in the different transmembrane pressure and flux for different membrane modules.
This SAMBR pilot plant was monitored for 114 days. Water sampling and measurement were carried out for system function evaluation on day 219. The results showed that the application of submerged aerobic membrane bioreactor for the treatment of pharmaceutical wastewater is feasible and successful.
