The Development of a Future Nitrogen Removal Process Using Fluidized-Bed Membrane Bioreactor
都市污水厭氧處理，處理效率不僅可優於現行消耗能源的好氧活性污 泥法，而且能產生生質能-沼氣，另外，厭氧處理所產生的廢棄污泥 只有好氧處理（活性污泥法）的十分之一。Inha WCUteam近年之研 究成果顯示污水處理廠已可為一「產能」系統，不再為一「耗能」系 統；同時，交大研究團隊對於都市污水厭氧處理後，產生高氨氮之衍 生問題，可提供「生物除氮技術」，提升污水處理廠出流水之回收再 利用之可行性，達成污水處理廠「產能且水回收再利用」之積極目標。 本國際研發團隊將研發結合厭氧流體化床薄膜生物反應器（FMBR) 與同時自營異營（厭氧氨氧化）生物除氮技術（SNAD)，進行生物除 氮、降解有機物產生能源；本系統可以增加污泥停留時間，有利於厭 氧氨氧化菌之生長，使得本技術的開發更可行且更具實用價值。|
In the past, the conventional nitrification process followed by denitrification was used for the removal of ammonium in the environment with the requirement of extensive aeration and external carbon source and the responsibility of 26% of the total greenhouse gas footprint from nitrous oxide (N2O) in water chain. However, this process was surpassed by a novel process called anaerobic ammonium oxidation process (Anammox) found in 1995. In the direct application of autotrophic anammox, nitrification of NH4+ to NO2- with O2 as the electron acceptor and then anoxic denitrification of NO2- to nitrogen gas with NH4+ as the electron donor. But, anammox remove only about 90% of the incoming nitrogen as NH4+/ NO2- and leaves 10% of nitrogen (N) as NO2- in the effluent. Moreover, it could not remove biological oxygen demand (BOD), which exists in most of wastewaters, since they are autotrophs. Therefore, we combines these two processes into an innovative process termed the simultaneous nitrification, anammox and denitrification (SNAD) in one single fluidized-bed membrane bioreactor (FMBR) by our international research team (Inha Univ., South Korea and National Chiao Tung University, Taiwan). The process topples the traditional nitrification-denitrification concept and the existing anammox application. The N and BOD removal responsible by AOB, AOA, denitrifiers and anammox microbes by the SNAD activity is controlled at a low dissolved oxygen (DO) resulting in huge energy savings in aeration. Another key figure of the SNAD-FMBR is to place the granular activated carbon (GAC) in it, serving as the fluidized-bed support material for microorganisms and the physical souring media for fouling control. Thus, the proposed process would be able to increase removal rate by highly detainment of biomass (especially for slow growing anammox bacteria) as well as to provide good effluent quality. The SNAD process would reduce N2O (a greenhouse gas) emission derived from nitrite by creating the zero-nitrite/nitrate scenario, since the produced nitrite/nitrate would be consumed either through anammox or denitrification immediately. The proposed system requires 60% less oxygen, reduces greenhouse gases emission, and improves removal efficiency in a small footprint reactor. The successful development of this proposed technology will not only make this environmentally sustainable and cost effective treatment technology immediately available for the wastewater industry but also overthrow the current biological nutrient concept. Furthermore, the study will advance the fundamental knowledge of each microbial community involved in the process.