| Description |
With increasing industrial activities in many parts of the world, a large amount of crude oil is being consumed daily. With the large number of offshore and onshore oil fields along with the transportation of crude oil and its products, the risk of oil spill increases accordingly. Big crude oil spill accidents have caused not only loss of the energy resource but also significant contamination to the environment and ecosystems, attracting intense attention in each occurrence. Small oil spills occur frequently, but with less notice worldwide on a daily basis on land, at sea, and throughout inland freshwater systems. Various approaches have been proposed to decontaminate oil spill sites according to individual environmental constraints. The main methods for in situ oil spill clean-up include biodegradation, controlled burning, sorption, dispersion, along with chemical oxidation, filtration, membrane process, and adsorption for lower oil concentrations. These existing methods have their own drawbacks such as long duration and harmful intermediates; new effective methods using a combination of the existing methods are necessary. In this study, a process train utilizing flotation, stage-1 sand filtration, heightened ozonation (HOT), and stage-2 sand filtration was used to deal with oil-contaminated water (2.5% oil) that would simulate oil spills under different water conditions, including tap water, Utah Lake water, and Great Salt Lake water representing fresh water, groundwater, and sea water contamination. Treatment was carried under different conditions and the optimum conditions were identified. Excellent operation flowrates were found to be 5.2, 8, and 2 cm/min for the flotation column, the first-stage sand filtration, and the second-stage sand filtration, respectively. The results showed that HOT treatment of 8 cycles at 100 psi was most effective and economical in terms of dosage for achieving desirable effluent quality (84.76% O&G removal) and sand filter's life capacity (150 times the sands volume before sands were exhausted). The new treatment train achieved 99.9 % oil and grease removal and > 99.8 % COD removal, with increased sCOD and BOD/COD ratio, which indicated the potential of further polishing biological treatment if needed. |
