研究冷卻水塔排放水回收再利用之經濟效益，所以在這裡以台灣南部某複循環電廠為例來作探討，因冷卻水塔排放，冷卻水塔須的補充水源成本分析，為了對於各項成本有進一步的了解，規畫3個可行性方案。
分別為方案一冷卻水塔排放水直接向自來水公司購水補充的方式，方案二冷卻水塔排放水經冷卻水塔排放水回收系統（Cooling Tower Basin Recycle System，CTBRS）處理後回收水補充回到冷卻水塔，方案三經CTBRS處理後的回收水除了補充到冷卻水塔利用外，另增加做為純水系統使用之原水（Raw water）。冷卻水塔排放水回收系統以奈濾技術（Nano Filtration，NF）及逆滲透技術（Reverse Osmosis，RO）程序處理冷卻水塔排放的廢水，並以工程經濟方法研究方案之經濟效益。
工程經濟的評估方法，如現值法、年值法、現金流量分析及敏感性分析等，進行成本分析、未來規劃的評估，並依評估方案所得結果做為決策參考，以便於方案中選擇最佳方案。由研究得知以工程經濟的分析方法，在民國97年底為幣值基準，在15年期間及利率4%條件下評估各可行案例中運轉成本。案例二為CTBRS處理後回收水再利用的運轉成本為每噸8.65元。案例三為增加CTBRS處理後回收水用途，加上回收當純水系統的原水，降低純水生產水成本，可提高經濟效益到運轉成本僅每噸7.69元。CTBRS回收再利用的效益皆優於方案一的購水成本每噸為9.41元。
因為運用化學處理於薄膜分離系統中，可使逆滲透膜組的成功應用更為廣泛；例如︰冷卻水塔排放水回收再利用。CTBRS的產水用途可選擇做為較經濟的使用，將帶來更高的效益；例如︰作為電廠中的純水系統的給水，可直接延長離子交換樹脂之壽命、操作時間及再生週期。所以案例三為方案中選擇最佳選擇的方案。
目前工業上廢水回收處理在技術上已經相當成熟，由於目前台灣自來水水價偏低，回收水整體成本仍會較現行自來水水價高。但考慮未來水價調漲趨勢，徵收水污費及以政府相關水資源法規規範等，在工程經濟的分析若是可以將環保等因素量化成有成本效益，例如廢水處理成本，減少水資源開發成本等，以便同時考量環保成本的話，那麼的評估到的結果能反應整體經濟效益，符合現今世界環保趨勢。

Economic benefits of cooling tower blowdown recycle research. So here as an example of a combined-cycle power plant in the south of Taiwan to be explored, due to cooling tower blowdown ,the water should be refill up the cooling tower basin, and its cost analysis, for a better understanding of costs, planning the feasibility of the three cases.
First Case is Cooling Tower Blowdown to make-up water directly to Taiwan Water Company the way to buy water, the second one is Cooling Tower Blowdown after Cooling Tower Basin Recycle System（CTBRS）treatment reclaimed water to refill up cooling tower. The third case is the reclaimed water of CTBRS in addition the use of cooling towers, the Pure Water System as use. CTBRS by Nano Filtration （NF） technology and Reverse Osmosis（RO） technology process to treat cooling towers blowdown, and to the case of economic benefits research programmed on the Engineering Economy Method.
Engineering Economy Methods, such as the Present Worth Method, the Annual Worth Method, The Cash Flow Analysis and Sensitivity Analysis, carried out as the cost of the assessment of future planning and assessment program in accordance with the results of reference for decision-making to facilitate the program choose the best option. According to our study, by analysis of engineering economy under the conditions of the interest rate 4% in 15 years period and the Republic of China 97 year's end as the currency value datum to analysis the operating costs of each case.
Case II is the reclaimed water of CTBRS with the operating costs of the 8.65 $NT/ton. Case III is to increase and Change the use of the reclaimed water of CTBRS, added to supply the pure water system and reduce pure water production cost can increase economic efficiency to the operating costs only 7.69 $NT/ton. The reclaimed water recycle benefits of the program are better than Case I cost of the purchase of water for 9.41 $NT/ton.
Because of the use of chemical treatment on the membrane separation system, RO membrane will enable the Group's successful application of more extensive; such as recycle cooling tower blowdown. CTBRS Product uses the option of producing more economical to use as result in a higher efficiency; such as the produce water to supply the pure water system in a power plant can be directly extended the life of ion exchange resins, operation time and the regeneration cycle. Therefore, Case ΙII is to select the options the best.
At present in the industry waste water recycling processing technically already quite was mature, because the present Taiwan sell off City water is low unit price, the reclaimed water overall cost still higher than the present City Water. But the consideration future the City Water will rise the tendency, will levy wastewater fee and the government correlation water resources laws and regulations standard and so on, if in the engineering economy analysis might factor quantifications and so on the environmental protection become has the cost benefit, for example the waste water processing cost, will reduce the water resources development cost and so on, in order to simultaneously consider the environmental protection cost the speech, such appraisal result be able to respond the whole economic efficiency, conforms to the nowadays world environmental protection tendency.

五大銀行（台銀、合庫銀、土銀、華銀及一銀)新承做放款金額與利率(98.6.24)，民98，中央銀行全球資訊網網址，Available：http://www.cbc.gov.tw/ct.asp?xItem=1079&CtNode=528&mp=1
王禮忠及賴祐，民97，合理水價之探討，水資源管理與政策研究中心，淡江大學，Available：http://www.water.tku.edu.tw/discuss/chat_discuss23.htm
台灣自來水公司用戶服務/抄表計費/水費及各項服務費收費標準，民97，台灣自來水公司網址，Available：http://www.water.gov.tw/04service/ser_c_main.asp
財團法人中興工程顧問社，民96年，廢污水再生利用技術研究-台中市福田水資源回收中心再生水試用計劃（1/2），經濟部水利署水利規劃試驗所。
能邦科技顧問股份有限公司，民96年，台南海水淡化廠調查規劃，經濟部水利署水利規劃試驗所。
財團法人成大研究發展基金會，民96年，台中海水淡化廠調查規劃，經濟部水利署水利規劃試驗所。
財團法人成大研究發展基金會，民96年，工業廢水再生利用產業試驗研究-以台南地區為例，經濟部水利署水利規劃試驗所。
趙幼梅、莊靜雨及葉茂淞，民96，間接冷卻排放水經濟可行之回收技術建立，2007台灣水利產業發展協會，台灣水利產業研討會，B-13。
黃泳塘、王國樑、朱敬平及鐘裕仁，民96，以薄膜單元回收工業區綜合性廢水之操作與成本分析，2007台灣水利產業發展協會，台灣水利產業研討會，B-35。
林發恩、莊靜雨、洪福亮及吳政峰，民95，應用薄膜技術進行鋼廠廢水回收之評估，2006台灣水利產業發展協會，台灣水科技週研討會。
陳鎮坤，民94，水回收再利用之經濟效益研究以印刷電路板業為例，國立中央大學環境工程研究所，碩士論文。
Chan S. Para原著、吳家宏、李文瑞、林亭兒、曾懷恩、蔣寬和及蔡澄雄編譯，民93，現代工程經濟，培生教育出版集團。
陳寬仁，民93，工程經濟學，（修訂三版），三民書局。
Conard Carlberg著，境影工作室譯，民93，Excel進階財務管理與案例分析，（初版），五南書局。
曾柏霖，民92，工業區汙水處理廠再生利用效益評估-以台南地區為例，立德管理學院資源與環境管理研究所，碩士論文。
許如欽，民91，工程經濟：理論與應用，（初版），三民書局。
林正芳，民89，薄膜程序於水處理的應用，2000土木水利 第二十六卷 第四期, page. 27-36,。
Alan Paton, Paul McCann and Nick Booth, 2006, Water Treatment for Fossil Fuel Power Generation, Report No. Coal R300 DTI/Pub URN 06/705.
Bilstad, T. , 1994, Nitrogen separation from domestic wastewater by reverse osmosis, Journal of Membrane Science, 102, pp.93-102.
Chan S. Para, 2004, Contemporary Engineering Economics, 3rd Edit, Pearson Education International.
Moch, Jr. I. , 2002, A 21st Century Study of Global Seawater Reverse Osmosis Operation and Capital Costs, Proceedings of IDA's World Congress on Desalination and Water Reuse, Manama, Bahrain, March 8-13.
Morin O.J, 1999, Desalting Plant Cost Update-2000, International Desalination Association.
Singapore’s national water agency, 2008, NEWater Visitor Centre, Singapore government, Available: http://www.pub.gov.sg/newater/Pages/default.aspx
Watertech Online, 2003, The United Nations World Water Development Report, 27, Available:http://unesdoc.unesco.org/images/0012/001295/129556e.pdf
Wilf, M., Alt,S., 2000 , Application of low RO membrane elements for reclamation of municipal wastewater, Desalination, 132, page.11-19.