Schäfer A I, Broeckmann A, Richards B S
Environmental Engineering, University of Wollongong, Wollongong NSW 2522, Australia.
Environ Sci Technol. 2007 Feb 1;41(3):998-1003. doi: 10.1021/es061166o.
In isolated communities where potable water sources as well as energy grids are limited or nonexistent, treating brackish groundwater aquifers with small-scale desalination systems can be a viable alternative to existing water infrastructures. Given the unavailability of power in many such situations, renewable energy is an obvious solution to power such systems. However, renewable energy is an intermittent power supply and with regards to the performance of intermittently operated desalination systems, only very limited experience exists, both with regards to efficiency as well as water quality. In this paper, this lack of knowledge is addressed by evaluating a system operated with varying parameters (pressure and flow) with constant power as a step toward defining a safe operating window, and they provide a basis for interpreting future data obtained with a renewable energy source. Field trials were performed on a brackish (5300 mg/L TDS; 8290 microS/cm) bore in Central Australia with a photovoltaic-powered membrane filtration (PV-membrane) system. Four nanofiltration and reverse osmosis membranes (BW30, ESPA4, NF90, TFC-S) and a number of operation parameter combinations (transmembrane pressure, feed flow, TFC-S) and operating parameters transmembrane pressure and feed flow were investigated to find the best operating conditions for maximum drinking water production and minimum specific energy consumption (SEC). The ESPA4 membrane performed best for this brackish source, producing 250 L/h of excellent drinking water (257 mg/L TDS; 400 microS/ cm) at an SEC of 1.2 kWh/m3. The issue of brine disposal or reuse is also discussed and the article compares the salinity of the produced brine with livestock water. Since the feedwater is disinfected physically using ultrafiltration (UF), the brine is free from bacteria and most viruses and hence can be seen more as a reusable product stream than a waste stream with a disposal problem.
在饮用水源和能源网络有限或不存在的偏远社区，使用小型海水淡化系统处理微咸地下水含水层可能是现有供水基础设施的可行替代方案。鉴于在许多此类情况下电力供应不足，可再生能源显然是为这类系统供电的解决方案。然而，可再生能源是一种间歇性电源，关于间歇运行的海水淡化系统的性能，在效率和水质方面仅有非常有限的经验。在本文中，通过评估一个在恒定功率下以不同参数（压力和流量）运行的系统来解决这一知识空白，以此作为定义安全运行窗口的一步，并为解释未来使用可再生能源获得的数据提供依据。在澳大利亚中部一口微咸（总溶解固体含量为5300毫克/升；电导率为8290微西门子/厘米）的水井中，使用光伏驱动的膜过滤（PV - 膜）系统进行了现场试验。研究了四种纳滤和反渗透膜（BW30、ESPA4、NF90、TFC - S）以及一些运行参数组合（跨膜压力、进水流量、TFC - S）和运行参数跨膜压力与进水流量，以找到实现最大饮用水产量和最低比能耗（SEC）的最佳运行条件。对于这种微咸水源，ESPA4膜表现最佳，在比能耗为1.2千瓦时/立方米的情况下，每小时可生产250升优质饮用水（总溶解固体含量为257毫克/升；电导率为400微西门子/厘米）。本文还讨论了浓盐水处置或再利用的问题，并将所产浓盐水的盐度与牲畜用水进行了比较。由于进水通过超滤（UF）进行物理消毒，浓盐水不含细菌和大多数病毒，因此与其说是存在处置问题的废物流，不如说是更可视为可再利用的产品流。
