Semiat R, Hasson D, Zelmanov G, Hemo I
Grand Water Research Institute-Rabin Desalination Laboratory, Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Water Sci Technol. 2004;49(2):211-9.
Disposal of RO concentrates emanating from inland brackish water desalination plants presents a difficult environmental problem. The solution adopted by Mekorot--the National Water Company of Israel--is to construct a 30 km waste disposal pipeline for collecting concentrates emanating from several RO desalination plants and discharging them into the sea. The discharged concentrates are highly supersaturated with respect to CaCO3. Scale precipitation during concentrate flow through the RO module is inhibited by the presence of anti-scalants. The retention time of the concentrate solution in the discharge pipe will exceed 100 hours. This raises the issue of the risk of scale precipitation in the discharge pipe that could impair its proper functioning. The aim of the present study was to provide data for guiding the design and operation of the disposal pipeline. The extent of the induction period prior to the onset of precipitation was measured in a pilot plant simulating flow of concentrate solutions dosed with anti-scalants. The parameters investigated were the scaling potential, the anti-scalant concentration and the presence of a mixture of several anti-scalants. The results of this study provide threshold scaling limits under various conditions.
内陆微咸水淡化厂产生的反渗透浓缩液的处理是一个棘手的环境问题。以色列国家水务公司梅科洛特采取的解决方案是建造一条30公里长的废物处理管道，用于收集来自多个反渗透淡化厂的浓缩液并将其排放到海中。排放的浓缩液中碳酸钙高度过饱和。在浓缩液流经反渗透模块期间，阻垢剂的存在抑制了水垢沉淀。浓缩液在排放管道中的停留时间将超过100小时。这就引发了排放管道中水垢沉淀风险的问题，而水垢沉淀可能会影响其正常运行。本研究的目的是提供数据以指导排放管道的设计和运行。在模拟添加了阻垢剂的浓缩液流动的中试装置中测量了沉淀开始前诱导期的时长。研究的参数包括结垢潜力、阻垢剂浓度以及几种阻垢剂混合物的存在情况。本研究结果提供了各种条件下的阈值结垢极限。
