(271c) Heightened Ozonation Treatment of Produced Water

Produced water contains dispersed and dissolved oil that create problems for their use and disposal. In addition, oil sheen can be visible near shoreline when low level of oil is discharged with the water. Ozonation as a treatment process for harmful contaminants has been studied for decades. However, ozone treatment of produced water has not been sufficiently explored. The dissolved and dispersed hydrocarbons in produced water are very difficult to remove. Although treated by the best available technologies, discharged produced water is still prone to formation of oil sheen on water surface. This research aims at exploring the beneficial use of ozone in treatment of produced water for oil removal and prevention of oil sheen. Other than the ordinary ozonation method by bubbling ozone/air mixture into the liquid phase, a unique method of introducing ozone to the reaction medium is developed that involves cyclic compression and compression with ozone. The method results in heightened ozone treatment of hydrophobic chemicals in the dissolved as well as dispersed phases, resulting in their rapid removal from water. Experimental results also show prevention of sheen can be achieved with short duration of ozone treatment. The extractable ozonation products are identified by GC/MS to analyze the ozonation intermediates and final products to understand reaction mechanisms. Compared with current treatment technologies, the HOT process can treat dissolved and dispersed hydrocarbons simultaneously and prevent further oil sheen formation. Although other technologies, such as biological methods, can effectively remove dissolved and dispersed oil, they are not as speedy and effective relative to the new HOT process. The new technology has the potential as a treatment technique for produced water and tailings water, enabling safe discharge to the environmental or rendering high-value reuses of the water possible.