Rapid expansion of the unconventional oil and gas extraction has increased American energy independence, but also led to increased production of large amounts of contaminated water. Wastewater from the oil and gas industry contains a wide range of contaminants. Injecting such contaminated water into disposal wells or discharging it to the environment jeopardizes freshwater resources. Conventional and membrane-based wastewater treatment techniques are often not effective choices to treat highly contaminated wastewater; however, a suitable way to remove contaminants from wastewater is to selectively separate water in a process analogous to humidification-dehumidification (HDH). Only a few studies have investigated the use of HDH for wastewater treatment. In this study, a novel HDH system is introduced for treating highly contaminated water, such as oil and gas flowback and produced water. In this HDH process, a non-condensable gas, such as air, mixes with wastewater vapor to facilitate the separation of contaminants. As a result, clean water condenses from the multicomponent gaseous mixture while air carries organic contaminants out of the dehumidification section. A laboratory apparatus was constructed and experiments were performed to investigate the HDH process for wastewater treatment and to study the effects of flow dynamics including air flow rate on the composition of treated water. Different contaminants including benzene, toluene, 2-propanol and 2-butoxyethanol were tested. Experimental results showed that the system can be successfully applied for removing volatile and/or toxic organic contaminants from wastewater. A representative multicomponent mixture of fracking wastewater was successfully treated using the experimental setup and clean water with quality of 98.3% was obtained. It was revealed that increasing the air-to-vapor mass ratio improves purity of treated water. Quantitative analysis showed that by increasing the air-to-vapor mass ratio from 0.6 to 5.9, the fraction of separated 2-propanol through the air was improved from 43% to more than 96% of the initial amount. ASPEN software was employed to simulate equilibrium conditions. Experimental results were observed to have lower mass fraction of residual contaminant in the treated water compared to equilibrium state.

非常规石油和天然气开采的迅速扩张提高了美国的能源独立性，但也导致了大量受污染水的产量增加。来自石油和天然气工业的废水含有多种污染物。将这些受污染的水注入处理井或排放到环境中会危及淡水资源。传统的和基于膜的废水处理技术通常不是处理高度污染废水的有效选择；然而，从废水中去除污染物的合适方法是在类似于加湿-除湿 (HDH) 的过程中选择性地分离水。只有少数研究调查了 HDH 在废水处理中的应用。在这项研究中，引入了一种新的 HDH 系统来处理高度污染的水，如油气回流和采出水。在此 HDH 过程中，不可冷凝的气体（例如空气）与废水蒸汽混合以促进污染物的分离。结果，干净的水从多组分气体混合物中冷凝，而空气将有机污染物带出除湿部分。构建了实验室设备并进行了实验，以研究用于废水处理的 HDH 工艺，并研究包括空气流速在内的流动动力学对处理后水组成的影响。测试了不同的污染物，包括苯、甲苯、2-丙醇和 2-丁氧基乙醇。实验结果表明，该系统可成功应用于去除废水中的挥发性和/或有毒有机污染物。使用该实验装置成功处理了具有代表性的多组分压裂废水混合物，获得了水质为 98.3% 的清洁水。结果表明，增加空气与蒸汽的质量比可以提高处理水的纯度。定量分析表明，通过将空气与蒸汽的质量比从 0.6 增加到 5.9，分离出的 2-丙醇通过空气的比例从初始量的 43% 提高到 96% 以上。ASPEN 软件用于模拟平衡条件。实验结果观察到，与平衡状态相比，处理过的水中残留污染物的质量分数较低。结果表明，增加空气与蒸汽的质量比可以提高处理水的纯度。定量分析表明，通过将空气与蒸汽的质量比从 0.6 增加到 5.9，分离出的 2-丙醇通过空气的比例从初始量的 43% 提高到 96% 以上。ASPEN 软件用于模拟平衡条件。实验结果观察到，与平衡状态相比，处理过的水中残留污染物的质量分数较低。结果表明，增加空气与蒸汽的质量比可以提高处理水的纯度。定量分析表明，通过将空气与蒸汽的质量比从 0.6 增加到 5.9，分离出的 2-丙醇通过空气的比例从初始量的 43% 提高到 96% 以上。ASPEN 软件用于模拟平衡条件。实验结果观察到，与平衡状态相比，处理过的水中残留污染物的质量分数较低。