Treatment of Oily-Waste Process Streams
Standard oily-wastewater remediation relies on API 650 for oily-wastewater separation (O/W/S) treatment using gravimetric lagoon separation, then reprocessing the recovered floatable slop oil, followed by chemical flocculation, then reprocessing the recovered oily sludge, followed by dissolved air flotation (DAF), then using holdingpond clarification of supernatant wastewater, before ‘land-farming’ application, which then results in a contaminated brown-field. Gravimetric and chemical treatment with land-farm application discharge had significant design shortcomings during routine process upsets, becoming under-sized as production increased, or as heavy rainfall resulted in uncontrolled storm runoff of the wastewater. API O/W/S technology certainly can’t be expected to be deployed effectively for remote oil and gas fields or offshore sites produced water as a package treatment plant option. Various new configurations of separation technology have expanded oily-wastewater treatment options, everything from hydro-cyclones to coalescing plate filters, membrane filtration, even the use of ultra-filtration to separate and concentrate pre-treated process waste streams. While these methods offer good process response through a wide range of flows, and may meet US total hydrocarbon cleanup regulations, they are incapable of meeting proposed European environmental protection legislation, and each creates a reject side-stream of highly contaminated effluent, which must be disposed of as haz-waste.