Removal of Oil From Oily Industrial Wastewater Through Resin Technology

Abstract

Abstract Produced water and industrial waste water contamination is given by a combination of the creation of stabilized oil emulsions and the presence of soluble oil components. Typical components include alkanes, BTEX (benzene, toluene, ethylbenzene and xylenes), high amounts of dissolved solids, suspended solids, heavy metals, high content of biochemical oxygen demand (BOD) and chemical oxygen demand (COD). Failing to clean-up this oily water before disposal can have severe environmental consequences. Since most conventional water-treatment technologies are also negatively impacted by the presence of emulsified oil, development of appropriate oil removal technology is also in the best interest of any water reuse scheme. This paper includes several trials that have been carried out with industrial wastewater water containing both emulsified and dissolved oil for the evaluation of performance of two polymeric resins. The present study has tested synthetic oil emulsions in a controlled environment to evaluate the impact of typical operating conditions on removal efficiency. Bench testing and piloting have been carried out with real wastewater originated from various sources in the Tarragona industrial petrochemical complex (Spain). Samples with oil content ranging from 10 to 1000 mg/L of Total Petroleum Hydrocarbons (TPH) have been tested. Results show that a coalescer-type resin can effectively target emulsified oil, and in the correct operating conditions can achieve up to 90-98% removal. Furthermore, this is a technology that is not negatively affected by high concentrations of oil. On the contrary, results indicate that higher concentrations of insoluble oil contribute to improving overall efficiency. It has been identified that residual TPH can be attributed to water-soluble species, because a second pass does not improve performance. A polymeric adsorbent can remove dissolved oil components-such as phenols, BTEX and PAH-with an efficiency of over 99.9%. However, rapid saturationa and its fouling problems when confronted with emulsified oil indicates ideal solution for treating oily waters would be successive treatment with a coalescer and an adsorbent resin. This study shows, through testing of real-life samples from industrial wastewater that polymeric resins are able to remove both the emulsified and dissolved oil from oily water, and how composition has a significant influence on its removal.