Taking the waste out of wastewater

摘要

Canadian shipyard company Vancouver Shipyards generates a wide variety of wastewaters, including oily bilge water, fuel/slop tanks water, tank wash water from gas freeing operations, ballast water, and wastewater from pressure washing machinery. Both salt and fresh wastewaters are contaminated with emulsified oil and grease, diesel, hydraulic oil, and a full range of marine fuel oils, plus heavy metals and suspended solids. Until relatively recently, the management of these wastewaters was proving to be problematic. The commercial technologies available to treat these sorts of wastewaters were evaluated, but no system could reliably meet the effluent discharge requirements for the various wastewaters at a reasonable cost. Until, that is, the company discovered an old technology called "electrocoagulation" (EC).