反渗透海水淡化技术在北方海岛的应用实例

Application case of reverse osmosis seawater desalination technology on northern islands

为解决长岛有人居住岛屿用水高峰期用水供需矛盾,确定采用以反渗透(RO)技术为核心的海水淡化工艺建设海水淡化站。介绍了反渗透海水淡化技术在长岛8个岛、9处海水淡化站的应用情况。该项目根据不同的海岛条件采用了不同的取水方式和预处理方案,主处理工艺采用二级砂滤+一级反渗透+二级反渗透+矿化的组合工艺,消毒采用现场制备次氯酸钠和管式紫外线方式,总制水量达5 200 t/d,出水水质达到了《生活饮用水卫生标准》(GB 5749—2006)标准。采用等压正位移式能量回收装置,总体节能率可达60%,产水耗电量为4.60 kW·h/t,总计产水成本为6.075元/t。该项目在1.5 a的运行时间内,出水效果稳定,可为北方海岛小规模海水淡化建设项目提供借鉴。

In order to solve the contradiction between water supply and demand in the peak period of water consumption on inhabited islands of Changdao island,the seawater desalination process with reverse osmosis(RO)as the core technology was adopted to construct seawater desalination station. Reverse osmosis seawater desalination technology was applied in nine seawater desalination stations on eight islands of Changdao island. The project adopted different water intake methods and pretreatment schemes according to different island conditions. The main treatment process was the combination process of secondary sand filtration+primary reverse osmosis+secondary reverse osmosis+mineralization. Disinfection was carried out by preparing sodium hypochlorite and tube ultraviolet light.The total water production was 5 200 t/d,and the effluent quality could stably reach Standards for Drinking Water Quality(GB 5749-2006). The overall energy saving rate could reach 60% with the isovoltage positive displacement energy recovery device. The electricity consumption of water production was 4.60 kW·h/t,and the total cost of water production was 6.075 yuan/t. Through over one and a half years operation,the effluent quality was stable,which could provide reference for other small-scale seawater desalination projects on northern islands.