Emulsified Bilgewater Treatment

In a ship's bilge, water mixes with oils, cleaners, and other contaminants to form a complex wastewater that can be harmful to the marine environment. Naval vessels carry oil/water separators (OWS) to prevent discharging oily wastes overboard. These OWS systems can remove oil from water; however, serious problems arise when other contaminants, e.g. detergents, are present. These ingredients cause the oily water to form an emulsion, which fouls the OWS and prevents its proper operation. Thus, the Navy is seeking improved methods of separating oils from emulsified bilgewater. Acceptable techniques must be compact, automated, and effective on a wide range of waste compositions. Electrocoagulation (EC) is a method of electrochemically inducing coagulation of dissolved ions, oils, or suspended solids to create a readily separable phase. EC effectiveness has been demonstrated on heavy-metals, fats, oils & grease, coal fines, and bacteria. Shore-based systems have successfully treated oily bilgewater. The industrial use of the EC process has been limited due to its inability to effectively compete with land-intensive chemical-coagulation processes. ADA proposes to develop and demonstrate a shipboard EC system that will take advantage of key EC attributes - simple operation, compact size, and broad applicability - to enable this technology for marine applications.