二階段厭氧流體化薄膜生物反應槽在自然溫度下處理生活污水效率之研究

Abstract

利用生物程序處理生活污水，傳統認知上的好氧適用於低濃度污水、厭氧只適用於高濃度污水或污泥的藩籬即將被打破。本研究採用以厭氧流體化生物反應槽 (AFBR) 與厭氧流體化薄膜生物反應槽 (AFMBR) 結合的二階段厭氧流體化薄膜生物反應槽 (SAF-MBR) ，利用流體化床提高厭氧微生物的處理效率，於自然的不控溫操作條件下啟動反應槽，並在馴養218天之後以實際生活污水進流 (進流濃度約為100~150 mg COD L-1) ；反應槽內預先植入顆粒化活性碳 (GAC) 作為載體，能有效避免在流體化床水力停留時間縮短時厭氧微生物被洗出系統，並在進流水變動過大時能提供良好的庇護。 反應槽操作至281天時，在水力停留時間2小時可達到總COD去除率84.5%以上，出流COD濃度為20.4 mg L-1；於299天時，1.28小時的水力停留時間能達到總COD去除率約66.5%，出流水COD濃度36.5 mg L-1。顯示此厭氧微生物系統具備在極短時間內將大量低濃度污水淨化的潛力。 其中厭氧薄膜也經過特殊的設計，在反應槽內GAC流體化的過程中，能有效降低其阻塞和反洗之需求、提高薄膜的壽命與實用價值。在產水通量 (Flux) 為16.125 LMH的階段，操作24天的薄膜平均壓差為-0.20 bar；產水通量為30.125 LMH的階段，操作18天的薄膜平均壓差為-0.25 bar，均未達反洗的需求。 因此在未來以厭氧結合薄膜的方式處理生活污水，將是一個快速、節能、高效率且值得永續利用的工法。

Recently, people start to refocus on anaerobic process than aerobic process, since the potential of anaerobic process has been discovered. The application of aerobic process to treat low strength wastewater has now become possible through some technical improvement. In this study, the new invention reactor which was a combination of anaerobic fluidized bed bio-reactor (AFBR) and anaerobic fluidized bed membrane bio-reactor (AFMBR), called staged anaerobic fluidized bed membrane bio-reactor (SAF-AFMBR). The SAF-MBR was started and operated at ambient temperature. After 218 days of acclimation then shift to real sewage, which the average concentration was around 100 to 150 mg COD L-1. The MRX-M granular activated carbon (GAC) was seeded as carrier in the reactors, for retaining anaerobic biomass within short HRT. GAC was proved can provide refuge when encounter influent shocks. Operated for 281 days, at 2 hours HRT can achieve total COD removal efficiency over 84.5% with effluent 20.4 mg COD L-1. At the end of the experiment (day 299) , only need 1.28 hour HRT to achieve total COD removal 66.5% and effluent COD concentration 36.5 mg L-1. This proves the system has ability to treat high volume of low strength wastewater in extremely short retention time. The GAC also can make self-cleaning of the membrane surface while fluidization, which reduce fouling and less the requirement of backwash. Through the new design, using anaerobic process to treat domestic wastewater could be an effective, fast and sustainable process in the future.