Remediation of TENORM scale waste generated from petroleum industry using single and mixed micelles solutions

Treatment of TENORM scale wastes generated from oil and gas production that contaminated by different radionuclides is an important societal, environmental, economical and technological challenge, due to the rise number of sites contaminated by these radionuclides. Bench-scale laboratory experiments were conducted to determine the removal characteristics of radium isotopes from TENORM-scale. This scale waste contained high level radioactivity (44,610 Bq/kg) due to the presence of radium isotopes (35,100 Bq/kg for Ra-226 and 9510 Bq/kg for Ra-228). In this study, three different types of surfactants polyoxyethylene sorbitanmonooleate (Tween-80), cetyltrimethylammonium bromide (CTAB) and sodium-dodecylsulfate (SDS) as micelle-forming agents were used for treating scale wastes by separating the most contaminated fraction of the TENORM-scale for disposal. It is found that the highest efficiency of radium isotopes was about 52% and 55% for Ra-226 and Ra-228, respectively using single micelles systems. Combined effect of mixed micelles produces synergistic effect in the remediation process, where the removals reached to about 80% for Ra-226 and Ra-228 were obtained using mixed micelles solutions. The scale-washing process water used in TENORM scale extractive washing is treated with conventional wastewater treatment technology or reused in successive washing for new scale waste. The results also point out that the treated water from the washing step was more effective compared to distilled water, probably due to surfactants contained in treated water. The data obtained in these studies may be considered as promising and efficient to treatment of TENORM scales economically. (C) 2019 Published by Elsevier B.V.