Produced Water Treament Using DAF With a Mixture of Ionic Liquids and Organoclay as Pre-treatment Chemicals

Abstract

With climate change ever still a focal point of discussion among the world leaders, amidst the growing interest in carbon capture, now than ever before, it has become more imperative to engage in not only innovative ways to treat water globally but also cost effective too, in order to ensure the sustainability, global acceptance and utilization of the process. The average production of water to oil in oil producing well is currently estimated at a ratio of 3:1 in favour of water, this number is estimated to rise to as high 12:1 in the next decade. Hence the onus is on researchers to meet up with the demands that come from the volume of produced water generated from these numbers in terms of treatment for discharge and reuse in the environment. Produced water treatment is very essential to the society as it facilitates better oil recovery from the reservoir, improved environmental condition and aquatic life sustainability, and also reuse in industrial processes such as oil sands, water reinjection and irrigation. In this present study, Experiments were done to determine the optimum oil removal efficiency using dissolved air flotation system under specified experimental conditions using a 3*3 Taguchi method of experimental design. An ionic liquid (1-ethyl-3-methyl-Imidazolium actetate) (EMIMAc) and an organoclay(OC) (JC 9450) were used as coagulant initially in the process to determine the optimum removal efficiency of oil, COD and turbidity at 3 different concentrations for both coagulants, the relationship between TDS, Salinity and Conductivity was also analyzed based on how they were affected by the different concentration levels and Recycle ratio. A third experimental set was done using both ionic liquid and organoclay together during mixing to determine the synergistic effect of the coagulants with DAF. In all experiments the zeta potential and pH of the feed were measured and compared with that of the treated water, and the relationship between both parameters analyzed. The highest removal efficiency obtained for the ionic liquid was 97.1% at a concentration of 200 ppm, while at a similar organoclay concentration of 360 ppm, the removal efficiency was obtained as 95.9%. The synergistic reaction between organoclay and ionic liquid yielded a removal efficiency of 96.95% at a concentration of 360 ppm OC and 50 ppm Emim[AC]. The removal efficiencies were compared with that obtained from control experiments using DAF only as well as using Coagulants only. At appropriate mixing levels, the removal efficiency of oil using each coagulant only was also observed to be greater than the control experiment of DAF only.