|摘要: ||活性污泥法因應處理各種不同廢水而有不同的處理程序組合及操作條件，但均會產生大量廢棄生物污泥，污泥的後續利用與處置所需要花費的成本頗高，而環境中的難分解污染物質也易累積在污泥之中，因此污泥的減量及其所含之難分解污染物質之降解為本研究目標。鄰苯二甲酸酯類 ( phthalate esters, PAEs ) 化合物常做為塑化劑添加在塑膠製品中，PAEs與高分子塑膠聚合物之間易受時間、溫度等影響，而逐漸釋放到環境水體中，因此本研究選用PAEs之鄰苯二甲酸二乙酯 ( diethyl phthalate, DEP ) 為目標污染物進行生物性降解試驗，並利用高溫好氧薄膜系統 ( thermophilic aerobic membrane system, TAMS ) 消化處理污泥與污泥中之DEP。|
高溫好氧薄膜反應槽之有效體積為25 L，溫度控制於55℃，並先以麩胺酸及蔗糖做為進流基質（COD ≒ 10,000 mg/L）進行水相馴養，而後再以同濃度COD之污泥為進流基質。但因系統處理效果不佳，因此系統重新植種高溫菌液且將系統溫度控制為45℃，並將進流基質改為麩胺酸、蔗糖及廢棄污泥。系統定期監測各項水質參數以觀察系統中微生物對污泥及難分解有機物降解之成效。此外，本實驗利用批次試驗求取高溫好氧薄膜系統中微生物於不同COD濃度（麩胺酸、蔗糖及廢棄污泥）之反應動力參數，並進一步探討文獻中微生物生長動力模式之適用性，且以PCR-DGGE觀察系統菌群組成。
The activated sludge system has different combinations and operating conditions to treat different wastewaters. The objective of this research is study the reduction of wasted sludge and the degradation of refractory organic compounds. Phthalate esters (PAEs) are usually added as plasticizer. It is known that PAEs and macromolecule plastic polymers are easy to separate and release to the environment. Thus the presence of refractory organics, such as PAEs, would be common in the treated wastewaters and sludge. Diethyl phthalate (DEP) was used as the target pollutant in this biodegradation test. A thermophilic aerobic membrane system(TAMS) was employed to degrade DEP in wasted sludge.
In this study, the thermophilic aerobic membrane bioreactor, with a volume of 25 L, was maintained at 55℃. Initially, a mixed thermophilic bacterial culture was acclimated with the influent substrate of 10,000 mg-COD/L which was made of glutamic acid and sucrose. Then the same concentration of the wasted sludge was substituted for the influent substrate. Due to the poor treatment results, the system re-seeded with thermophilic microorganisms. The influent substrate was modified containing glutamic acid, sucrose and wasted sludge. The bioreactor was operated at 45℃. In addition, kinetic model was also determined for this thermophilic aerobic membrane system with a series of batch reactors. Furthermore, PCR-DGGE was applied to determine the microbial communities of mixed culture in the bioreactor.
When the influent substrate was made of glutamic acid, sucrose and wasted sludge, the result showed that the removal efficiency of MLSS was only 14%, the highest removal efficiency of tCOD was 28%. The removal efficiencies of sCOD and DEP in the effluent were 99% and 95%, respectively. The removal rate of DEP in the wasted sludge was 90%. Additionally, the maximum specific substrate utilization rate with 5.18 mg-sub/mg-cell-day was found from the batch test. These results have showed that the thermophilic aerobic system has poor degradation rate of sludge but has good treatment efficiency of DEP.