馬祖地區湖庫水因蒸發量大、呈現優養化或鹽化，水質普遍不佳，自2010年底南竿日產950噸海水淡化廠加入營運，迄2018年，海淡水供應量為70%，湖庫水降低為30%。本研究以效益評估方法提出馬祖地區海水淡化系統建議配置，成本包括設置成本及操作成本，效益則為產水量乘以單價。設置成本以海水淡化前處理設備為主，操作成本包括2017及2018年之濾材耗損、維修費及電費，並導入季節差異因子；配置上收集兩種不同海水淡化系統之成本數據，一為超微濾(Ultra Filter, UF)前處理搭配柱塞式高壓泵RO系統，一為砂濾(Sand Filter, SF)前處理搭配離心式高壓泵RO系統。分析發現，採用UF搭配柱塞式高壓泵RO系統，產水單價成本為每公噸22.16元，較SF搭配離心式高壓泵RO系統之產水單價成本每公噸29.19元為佳。 Water quality in the reservoir of Mazu area is poor due to the large evaporation, favorable nutrition and salinization. From the end of 2010, the desalination plant in Nanxun started operation to produce water 950 ton per day. In 2018, fresh water supplied by desalination plant is 70%, and lake 30%, respectively. This study adopted the cost-benefit method to evaluate the proposed seawater desalination system in Mazu area. The cost includes installation cost and operation cost. The installation cost is mainly based on seawater desalination pretreatment equipment. The benefit is the multiplation of production water volume and unit price. The operation cost includes the filter material consumption, maintenance fee and electricity fee in 2017 and 2018. Seasonal difference factor is also discussed. Data of two different seawater desalination systems were collected. One is the combination of ultrafiltration (UF) pretreatment and the plunger high pressure pump (PHP) Reverse Osmosis (RO) system. Another one is the combination of sand filter (SF) pretreatment and centrifugal high pressure pump (CHP) RO system. After analyzing the construction and operation costs, production unit price of UF&PHP is NTD. 22.16 per ton, and SF&CHP = NTD. 29.19, respectively. UF&PHP is better than SF&CHP in performance.
