典型海水淡化系统的水足迹评价

海水淡化是缓解我国水资源匮乏的有效方式之一。目前国内外主要关注海水淡化技术的成本和水质，缺乏对海水淡化水资源效益的量化评价。根据ISO水足迹理论，划定海水淡化量化边界，进行典型海水淡化工艺生产阶段清单分析，建立了海水淡化水足迹量化及评价方法。结果表明:低温多效蒸馏水稀缺足迹比反渗透水稀缺足迹高出3~4倍，2种工艺的海水淡化水稀缺足迹的关键影响因素均为电耗；反渗透工艺的水劣化足迹均低于低温多效蒸馏工艺海水淡化。因此，在样本范围内，反渗透工艺的水资源效益整体优于低温多效蒸馏工艺。水足迹评价研究结果揭示，海水淡化生产阶段的水资源消耗和水质影响，有助于引导海水淡化技术向提高水资源效益和降低能耗、消除水污染的方向发展，以期为海水资源科学开发利用提供技术支撑。

WATER FOOTPRINT EVALUATION OF TYPICAL SEAWATER DESALINATION SYSTEMS

Seawater desalination, in rapid development, is an effective measure to alleviate the freshwater scarcity crisis in China. However, there is a significant concern about the water quality and cost of the desalination systems, but little attention has been paid to the quantitative evaluation of water resource efficiency. Based on the ISO water footprint principle, this work delineated the system boundary of sea water desalination, performed the inventory analysis of the production phase of seawater desalination systems, and proposed a method for water footprint quantification and evaluation of typical seawater desalination systems. Evaluation results revealed that the scarcity footprint of the multi-effect distillation(MED) technology was 3~4 times higher than that of the reverse osmosis(RO) technology, and the power consumption was the determining factor for the water footprint of all the technologies. The degradation water footprint of RO technology was much lower than that of MED. Overall, the RO technology showed more excellent water resource efficiency than the MED among the studied cases. This work revealed the consumption and pollution of water resources in seawater desalination production via the water footprint analysis. It may help develop the sea water desalination improve water resource efficiency, reduce energy consumption and eliminate water pollution, and provide support for scientific development and utilization of seawater.