European Commission, Joint Research Centre, Italy.
Federal University of Parana', Brazil.
Water Res. 2020 Sep 1;182:115906. doi: 10.1016/j.watres.2020.115906. Epub 2020 May 15.
While we increasingly turn to desalination as a secure water supply, it is still perceived as an expensive and environmentally damaging solution, affordable only for affluent societies. In this contribution, we recast desalination from one of a last resort to a far-reaching, climate change mitigating, water security solution. First, we argue that the benefits of desalination go beyond the single-use value of the water produced. If coupled with water reuse for irrigation, desalination reduces groundwater abstraction and augments the water cycle. As such, it may support both adaptation to, and mitigation of climate change impacts by deploying plentiful water for human use, with all the benefits that entails, while helping preserve and restore ecosystems. Second, we counter two arguments commonly raised against desalination, namely its environmental impact and high cost. The environmental impact can be fully controlled so as not to pose long-term threats, if driven by renewable energy. Desalination may then have a zero carbon footprint. Moreover, appropriately designed outfalls make the disposal of brine at sea compatible with marine ecosystems.. Recovery of energy, minerals and more water from brine reject (particularly in the form of vapour for cooling to enable more crops and vegetation to grow), while possible, is often hardly economically justified. However, resource recovery may become more attractive in the future, and help reduce the brine volumes to dispose of. When fresh water becomes scarce, its cost tends to go up, making desalination increasingly economic. Moreover, desalination can have virtually no environmental costs. Considering the environmental costs of over-abstraction of freshwater, desalination tilts the balance in its favour.
虽然我们越来越多地将海水淡化作为一种安全的供水方式，但它仍然被认为是一种昂贵且对环境有害的解决方案，只有富裕社会才负担得起。在本贡献中，我们将海水淡化从最后的手段重新定义为一种具有深远意义、能够缓解气候变化、保障水安全的解决方案。首先，我们认为海水淡化的好处不仅仅在于所生产的水的一次性使用价值。如果与灌溉用的水再利用相结合，海水淡化可以减少地下水开采，并增加水循环。因此，它可以通过部署大量水资源来支持人类使用，从而适应和缓解气候变化的影响，同时带来所有相关的好处，同时帮助保护和恢复生态系统。其次，我们反驳了两个常见的反对海水淡化的论点，即其环境影响和高成本。如果由可再生能源驱动，海水淡化的环境影响可以得到完全控制，从而不会造成长期威胁。海水淡化的碳足迹可能为零。此外，适当设计的排水口可以使海水淡化厂的盐水排放与海洋生态系统兼容。从盐水废水中回收能源、矿物质和更多的水（特别是以蒸汽的形式用于冷却，以促进更多的作物和植被生长）虽然是可行的，但在经济上往往难以证明其合理性。然而，资源回收在未来可能会变得更有吸引力，并有助于减少要处理的盐水体积。当淡水资源变得稀缺时，其成本往往会上升，这使得海水淡化的经济性日益增强。此外，海水淡化几乎没有环境成本。考虑到过度开采淡水的环境成本，海水淡化有利于环境。
