Produced water handling has been an issue of concern for oil and gas producers as it is one of the major factors that cause abandonment of the producing well. The development of effective produced water management strategies poses a big challenge to the oil and gas industry today. The conversion of produced water into irrigation or fresh water provides a cost effective tool to handle excessive amounts of the produced water. In this research we proposed on-site produced water treatment units configured to achieve maximum processing throughput. We studied various advanced separation techniques to remove oil and dissolved solids from the produced water. We selected adsorption as the oil removing technique and Reverse Osmosis (RO) as the dissolved solids removing technique as being the best for our purpose. We performed experiments to evaluate operating parameters for both adsorption and RO units to accomplish maximum removal of oil and dissolved solids from the produced water. We compared the best models fitting the experimental data for both the processes, then analyzed and simulated the performance of integrated produced water treatment which involves adsorption columns and RO units. The experimental results show that the adsorption columns remove more than 90% of the oil and RO units remove more than 95% of total dissolved solids from the produced water. The simulation results show that the proper integration and configuration of adsorption and RO units can provide up to 80% efficiency for a processing throughput of 6-8 gallons per minute of produced water. From an oil and gas producer’s viewpoint output from the produced water treatment system is a revenue generating source. The system is flexible and can be modified for the applications such as rangeland restoration, reservoir recharge and agricultural use.

Produced water handling has been an issue of concern for oil and gas producers as it is one of the major factors that cause abandonment of the producing well. The development of effective produced water management strategies poses a big challenge to the oil and gas industry today. The conversion of produced water into irrigation or fresh water provides a cost effective tool to handle excessive amounts of the produced water. In this research we proposed on-site produced water treatment units configured to achieve maximum processing throughput. We studied various advanced separation techniques to remove oil and dissolved solids from the produced water. We selected adsorption as the oil removing technique and Reverse Osmosis (RO) as the dissolved solids removing technique as being the best for our purpose. We performed experiments to evaluate operating parameters for both adsorption and RO units to accomplish maximum removal of oil and dissolved solids from the produced water. We compared the best models fitting the experimental data for both the processes, then analyzed and simulated the performance of integrated produced water treatment which involves adsorption columns and RO units. The experimental results show that the adsorption columns remove more than 90% of the oil and RO units remove more than 95% of total dissolved solids from the produced water. The simulation results show that the proper integration and configuration of adsorption and RO units can provide up to 80% efficiency for a processing throughput of 6-8 gallons per minute of produced water. From an oil and gas producer’s viewpoint output from the produced water treatment system is a revenue generating source. The system is flexible and can be modified for the applications such as rangeland restoration, reservoir recharge and agricultural use.

Produced water is one of the major by products of oil and gas exploitation which is produced in large amounts up to 80% of the waste stream. Oil and grease concentration in produced water is the key parameter that is used for compliance monitoring, because it is easy to measure. For Canadian offshore operations, the current standard is a 30-day volume weighted average oil-in-water concentration in discharged produced water not exceeding 30 mg/L. Treatment of produced water may therefore be required in order to meet pre-disposal regulatory limits. The measurement of oil in produced water is important for both process control and reporting to regulatory authorities. Without the specification of a method, reported concentrations of oil in produced water can mean little, as there are many techniques and methods available for making this measurement, but not all are suitable in a specific application. The first part of this study focused on selecting a suitable analytical method for oil and grease measurement in oil field produced water. Petroleum ether was found to offer a comparative dissolution of crude oil as dichloromethane and hexane; it was therefore used as the solvent of choice for the UV-Vis spectrophotometric analysis of oil and grease in synthetic produced water. Results from the UV-Vis spectrophotometric and FTIR spectrometric analytical methods were found to be comparable; it confirmed that UV-Vis spectrometry could potentially serve as an alternative method for measuring oil and grease in oil field produced water. However, while the UV-Vis method may have limitations in measuring oil and grease concentrations below 30 mg/L, the FT-IR method was found to be equally efficient at measuring both high and low oil and grease concentrations. Dissolved air flotation (DAF) was the primary treatment technology investigated in this study for removing oil and grease from synthetic produced water. By itself, DAF achieved less than 70% oil and grease (OG) removal, and was not able to achieve a clarified effluent OG concentration of 30 mg/L required for regulatory discharge limits. At an optimum condition of 20 mg/L ferric chloride (FeCl3) at pH 8 (70.6% OG removal), coagulation was found to significantly improve the performance of the DAF unit (p < 0.05). At the optimum conditions of 100 mg/L PAC dose, pH 8 and a mixing time of 10 minutes (77.5% OG removal) and 300 mg/L OC dose, pH 8 and a mixing time of 10 minutes (78.1% OG removal), adsorption was also found to significantly improve the performance of the DAF unit (p < 0.05 in both cases). Adsorption with organoclay was recommended as the best pre-treatment for optimizing the performance of DAF in removing oil and grease from offshore oil field produced water. The bench-scale experiments showed that turbidity removal results were consistent with the OG removal results. Without pre-treatment, DAF achieved significant removal of benzene from produced water due to the volatile nature of benzene. Therefore comparable levels of benzene removal was observed by the DAF, FeCl3/DAF, PAC/DAF and OC/DAF treatment schemes; 79.3 %, 86.6 %, 86.5 %, 83.5% respectively. Finally, as benzene is known to be carcinogenic to humans, this study recommends the incorporation auxiliary equipment in its design, for the treatment of the off-gas (VOCs, particularly BTEX) released during the removal of dissolved oil from the oil field produced water.