The safe and economical management of shale gas flowback and produced water (FPW) with the goal of zero-liquid discharge (ZLD) is of paramount significance to the sustainable development of the energy industry. This challenge is still widely impending, due to severe limitations related to the complexity of FPW streams and high costs associated with their treatment. A long-term feasible solution is represented by solar-driven interfacial evaporation (SIE), a low-cost and environmentally friendly desalination technology. Technical and economic analyses show that even in the Sichuan Basin, where solar intensity is low and the volume of FPW is large, 4000 m of solar still would be sufficient to accomplish ZLD with a capital cost lower than $ 1 m, significantly cheaper than traditional membrane-based and thermal-based technologies (with costs above $ 15 m). Beneficial products, including condensate water and crystalline salts, may also be effectively recovered in this process, although design improvements are needed in this area. This study also discusses possible solutions to address the passage of volatile organic compounds into the effluent and to achieve the smart recovery of strategic resources, such as lithium and rare earth elements. The major current challenges of solar-driven evaporation for the beneficial management of FPW are scaling and fouling, cost-effective latent heat recovery, the scalability of the systems, and efficient water production and salts harvesting. These issues require ad hoc research efforts, analyses, and pilot testing.

中文翻译：

---

太阳能驱动的页岩气废水现场界面蒸发淡化及资源化

以零液体排放（ZLD）为目标的页岩气返排和采出水（FPW）的安全、经济管理对于能源行业的可持续发展至关重要。由于 FPW 流的复杂性及其治疗相关的高成本相关的严重限制，这一挑战仍然迫在眉睫。太阳能驱动的界面蒸发（SIE）是一种长期可行的解决方案，这是一种低成本且环保的海水淡化技术。技术经济分析表明，即使在太阳强度较低、FPW体积较大的四川盆地，4000m的太阳能仍足以完成ZLD，且资本成本低于100万美元，明显比传统方式便宜基于膜和基于热的技术（成本超过 1500 万美元）。包括冷凝水和结晶盐在内的有益产品也可以在此过程中有效回收，尽管这方面需要改进设计。这项研究还讨论了可能的解决方案，以解决挥发性有机化合物进入废水的问题，并实现锂和稀土元素等战略资源的智能回收。目前太阳能驱动蒸发对于 FPW 有益管理的主要挑战是结垢和结垢、具有成本效益的潜热回收、系统的可扩展性以及高效的水生产和盐收集。这些问题需要专门的研究工作、分析和试点测试。