页岩气开采的水污染问题及其综合治理技术

Shale Gas Produced Water Contamination and Its Comprehensive Treatment

页岩气作为一种清洁、低碳、高储量的非常规天然气能源,已成为全球油气资源勘探开发的新亮点。目前,页岩气最主要的开采方式是水力压裂技术,其开采过程需消耗大量淡水资源,并产生巨量高盐废液。如何经济高效处理页岩气废液和实现水循环利用对页岩气的长足发展和环境保护有着举足轻重的意义。本文从页岩气开采的技术原理出发,分析了开采过程中产生的废水成分特点,讨论了可用于废水处理的技术,包括重复使用法、机械蒸汽压缩法、膜蒸馏法、反渗透法、正渗透法、电絮凝技术、臭氧催化氧化技术等,并评估了各种水处理技术的优势与不足,表明了多种技术杂化综合的水处理系统将成为页岩气开采废水处理方案。

Shale gas is considered a form of clean unconventional natural gas with low carbon footprint and huge reserves, and has increasingly attracted attention as a new energy resource around the world. In recent years, the hydraulic fracturing technique has become very common in wells for shale gas drilling, which consumes tons of fresh water and produces a large amount of high salinity water. Managing the produced water and promoting cost-effective water reuse is a major challenge for maintaining the profitability of shale gas extraction while protecting public health and the environment. In this article, the hydraulic fracturing process is reviewed and the composition of shale gas produced water is analyzed. Then, the promising techniques of treating wastewater, including mechanical vapor compression, membrane distillation, reverse osmosis, forward osmosis, electrocoagulation, and ozone catalytic oxidation, are reviewed respectively, followed by a discussion on their advantages and challenges. It is concluded that the hybrid system combing more than one technique to treat wastewater could be a promising approach to real application.