Membrane Filtration Enhanced by Adsorption and Oxidation for Improved Treatment of Decanted Water from Marine Oil Spill Responses

Canada's current oil spill response regime requires that all the collected oil-water mixture (30% oil and 70% water on average) must be stored in the response vessels and transported to shore for treatment, and the discharge of decanted water back into the spill site is prohibited by Canada's Fisheries Act. Also, the conventional methods such as gravity-driven oil-water separation technologies are not able to treat the decanted water onsite adequately. As a result, the current oil spill response capacity and efficacy are drastically constrained. To improve the efficacy of onsite oil decanting thus minimizing the spill propagation and its potential environmental impacts, there is a pressing need to develop advanced solutions for achieving sufficient and effective treatment of decanted oily wastewater that would enable its safe disposal at sea. At Dalhousie, a unique pilot-scale submerged membrane filtration plant (i.e., Dal-SMBR) has been developed and its potential for oil decanting has been tested with some promising results being achieved. As a logic extension, this research is proposed to continue the efforts on R&D of oil decanting technologies through integrating different techniques into one framework. The main tasks entail: (1) continue polishing the Dal-SMBR plant with improved/optimized performance on permeate throughput and oil removal rate; (2) investigate the capabilities of different oxidants (such as ozone, hydrogen peroxide, Fenton's reagent, and oxygen) in removing emulsified and dissolved oil from the effluent and explore the capabilities of advanced oxidation techniques (e.g., electrochemical oxidation (ECO) and supercritical water oxidation (SCWO)) in mineralizing hydrocarbons; (3) examine the potentials of different sorbents (e.g., organoclays or P/GAC (powered/granular activated carbon)) in removing oil droplets and explore its capabilities as an enhancement technique; and (4) develop a modular sequential treatment train through integrating oxidation, adsorption, and membrane filtration into one technology framework for advancing the onsite oil decanting practices with improved effectiveness and stability. A series of experiments will be conducted to test the technology; different crude oils, concentrations, salinity, and emulsification forms will be considered. Different excises will be experimented to replicate field oil emulsification to gain a good understanding of emulsification mechanisms and to facilitate the development of a standard lab-based oil emulsification protocol and guideline. The developed technology will not only bring significant environmental, economic, and social benefits to Canada, but also enhance Canada's capabilities and leading role in the oil decanting field. This research will also help train HQPs, who will be well equipped with expertise in marine oil decanting and oily water treatment to be next-generation oil spill researchers, responders, and decision makers for Canada.