A gas hydrate process for high-salinity water and wastewater purification

Abstract

This study investigates the effectiveness of a hydrate-based water purification process on high-salinity and wastewater samples. Testing involved a 4-L-scale novel apparatus using HFC134a as a guest molecule during a continuous hydrate formation–pelletization–dissolution process. Each stage of the succeeded in removing 80–85% of individual dissolved contaminants from highly polluted water. This is the first study to meaningfully demonstrate the ability to purify highly polluted water by applying the proposed method to water with very high concentrations of salts or sugars that exceed the range treatable by reverse osmosis. In a single-stage hydrate process with no pre-or and post-treatment, the average removal efficiencies of ionic compounds in seawater, hypersaline brine (total dissolved solid ⁓150,000 mg/L) and contaminants from wastewater (Coca-Cola beverage, chemical oxygen demand ⁓80,000 mg/L) were 89%, 80%, and 81%, respectively. This study illustrates the effective and economic application of the proposed method and apparatus to the purification of high-salinity water and wastewater under various conditions.