|摘要: ||本提案之研究目標，主要是針對以挖井、手搖幫浦採取地下水，並經簡單砂濾方式處理之經濟蕭條第三世界國家，提出一低成本與易操作，可直接使用於一般家庭與社區地下水之硝酸鹽與砷污染處理技術。本研究特點為: 1.結合流體化床、零價鐵還原技術，除探討奈米Fe0/CO2 程序處理硝酸鹽污染用水之反應機制；與串聯流體化砂濾床中氧化鐵覆膜石英砂最佳形成條件外；2.將融入資源回收再利用理念，回收流體化砂濾床中之氧化鐵覆膜石英砂，進行砷去除吸附動力與競爭因子影響性探討。第一階段，將探討CO2 曝氣酸性環境下，NO3 -被還原降解情形與流體化砂濾床中空氣曝氣條件之控制，以建立有利Fe2+轉換成Fe3+，並可形成氧化鐵附著於石英砂表面之有利環境，以達去除溶液中NO3 -與之Fe2+目的。此結果有助於硝酸鹽降解機制之瞭解，並作為日後氨氮或氮氣去除系統設計重要參考資料，且提供了後續砷去除試驗所需材料。第二階段將回收前述流體化砂濾床中氧化鐵覆膜石英砂，進行表面理化特性與吸附平衡動力分析，並藉部份因子實驗設計，對合成含砷地下水進行吸附競爭重要影響因子篩選。藉由本計畫之完成，將可對“奈米Fe0/CO2 程序串聯流體化床處理技術”提供硝酸鹽處理成效與砷去除衍生效益間之可用資訊，以達經濟技術研發之目的。本計畫預計以二年時間完成上述目標，預期本計畫順利完成後，其具體成果如下： (1).反應系統硝酸鹽去除機制之瞭解除應證系統操作成效與收集日後處理現地地下水質所需資料外，於硝酸鹽去除過程中，其去除效率與衍生因子(亞硝酸鹽、氨氮或氮氣)間質量平衡機制，與其他相關研究之異同點可獲得充分了解。 (2).技術衍生效益資訊之獲得本研究雖於二階段中分別完成硝酸鹽與砷之去除，但因落實了資源回收再利用理念，其間砷去除為衍生之附加價值，若從經濟成本效益考量觀之，將可印證本技術為一低成本操作系統；且實驗所得資訊，將可為日後硝酸鹽–砷併除系統之設計提供有用參考資料。|
The main purpose of this paper is to provide a low-cost and easily-operated treatment technology of nitrate and arsenic polluted groundwater that may be directly applied by the common families and communities in economically backward countries, the third world countries in general, in which groundwater is obtained by well sinking and manual bump with simple sand filter. This research is characterized by: 1. in combination with the technology of fluidized bed and reduction of Fe0 , in addition to discussing reaction mechanism of nitrate polluted water treatment by nanoFe0/CO2 procedure combined with fluidized sand filter bed, and the optimal formation condition of iron-oxide coated sands; 2. integrated with the idea of recycling iron-oxide coated sands from fluidized sand filter bed, discussing the sorption kinetics and the effect of competition factors in arsenic removal. The 1st stage of this research discusses the circumstances of reduction and degradation of NO3 - in theCO2 aeration and acid environment and discusses condition control of air aeration in fluidized sand filter bed so that Fe2+ is transformed to Fe3+ and sands are coated with iron-oxide which will, however, realize the object of NO3 - and Fe2+ removal. This result is not only helpful to understand the degradation mechanism of nitrate but supplies valuable references for future design of ammonia nitrogen or nitrogen removal system and essential materials for follow-up arsenic removal tests .In the 2nd stage of this research, the above-mentioned iron-oxide coated sands will be recycled from the fluidized sand filter bed, and analyses on physical-chemical surface characteristics and adsorption equilibrium kinetics will be conducted; Moreover, through fractional factorial designs, key influence factors on adsorption competition in synthetic arsenic-contained groundwater will be screened. Upon completion of this project, applicable information related to the effect of nitrate treatment and the benefit from arsenic removal will be made available for the technology of nanoFe0/CO2 procedure combined with fluidized sand filter bed, which will accomplish the economic purpose this technologic research desires. The goal of this project is estimated to be achieved in 2 years. It is predicted that the outcome of this project is as follows in detail: (1). Realization of nitrate removal mechanism in reaction system Apart from suggesting the effect of the operation of reaction system and collection of materials for future treatment of groundwater quality, removal rate of nitrate, mass balance mechanism between derived factors(nitrites, ammonia nitrogen and nitrogen), as well as differences and similarities between this research and other relevant researches can be more understood. (2). Access to information on technology-derived benefit Nitrates and arsenics will be removed respectively in the 2 stages of this research, during which, added value is derived from the removal of arsenics as result of implementation of resource recycling. In the light of economic cost and benefit, this technology is a low cost operation; Furthermore, the information from the tests can be provided as useful reference for the later design of nitrate-arsenic removal.