Purpose of Review

Membrane distillation (MD) has been known as a promising water treatment process for many years. However, despite its advantages, MD has never been able to compete with other processes for industrial water treatment and supply. Instead, it has been orientated towards several unique strategic water treatment applications. This review aims to uncover the opportunities and technical challenges pertinent to the MD process and the current status of its strategic water treatment applications most notably including decentralised small-scale desalination for fresh water provision in remote areas, hybridisation with forward osmosis (FO) for treatment of challenging polluted waters, regeneration of liquid desiccant solutions for air conditioning, and treatment of acid effluents for beneficial reuse.

Recent Findings

Pilot and small-scale MD systems have been demonstrated for decentralised desalination using various renewable energy sources to supply fresh water in remote, rural areas and on ships where other desalination processes are inefficient or unfeasible. For this strategic desalination application, MD is technically viable, but more works on configuration modification and process optimisation are required to reduce the process energy consumption and water production costs. For the three other strategic applications, the technical viability of the MD process has been proved by extensive lab-scale researches, but its economic feasibility is still questionable due to the lack of large-scale evaluation and the uncertain costs of MD systems.

Summary

The orientation of MD towards strategic water treatment applications is clear. However, huge efforts are required to facilitate these applications at commercial and full scale.

中文翻译：

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用于战略水处理应用的膜蒸馏：机遇，挑战和现状

审查目的

膜蒸馏（MD）多年来一直被认为是一种有前途的水处理工艺。但是，尽管具有优势，MD仍无法与其他工艺进行工业水处理和供应的竞争。相反，它已针对几种独特的战略性水处理应用程序进行了开发。此次审查旨在发现与MD流程相关的机遇和技术挑战，以及其战略性水处理应用程序的当前状态，其中最显着的包括为偏远地区提供淡水的分散式小型海水淡化，与正向渗透（FO）混合处理挑战性的污染水，用于空调的液体干燥剂溶液的再生以及酸废水的处理，以利于再利用。

最近的发现

已经证明了使用小型和小型MD系统进行分散式海水淡化的方法，该系统使用各种可再生能源在偏远的农村地区和其他海水淡化工艺效率低下或不可行的船舶上提供淡水。对于这种战略性的海水淡化应用，MD在技术上是可行的，但是需要进行更多的配置修改和工艺优化工作以减少工艺能耗和水生产成本。对于其他三个战略应用，MD过程的技术可行性已通过广泛的实验室规模研究证明，但由于缺乏大规模评估和MD系统成本不确定，其经济可行性仍然值得怀疑。

概要

MD面向战略性水处理应用的方向很明确。然而，需要大量的努力来促进这些应用在商业上和大规模的应用。