Restrictions on land disposal of oily refinery wastes has forced much of the refining industry to bear the high cost of incinerating these wastes. Valero has developed and installed a Bio-Slurry Reaction Process (BSRP) to treat primary separation sludge (F037), API separator sludge (K051), DAF float (K048) and slop oil emulsion solids (K049). Valero generates 9,000 tons of dilute waste per year.
Bench scale treatability studies were performed by Radian that verified that the BSRP can meet Best Demonstratable Available Technology (BDAT) standards. Key components of the process are: 1)Centrifugation for initial recovery of recyclable oil and thickening of solids slurry. 2)Bioslurry treatment with sequential reactors. 3)Chemical stabilization of metals. 4)Centrifugal dewatering of residual sludge. All processes are performed in tanks.
The unit is presently treating waste at a nominal rate of 2,000 tons per year. (Initial separation by the centrifuge reduces the 9,000 tons of waste to 2,000 tons of waste plus recoverable oil.) The residual BDAT solids are still a listed hazardous wastes and can be disposed of in a RCRA Subtitle B hazardous waste landfill.
Details of Reductions
Additional Information :
The total capital investment and operating costs are estimated to be $400/ton. Valero believes the residuals will qualify for delisting; if so, Valero will pursue delisting the residual as the process become stable. Recovery of oil amounts to an economic gain of approximately $125/ton of waste treated. Because the system is totally enclosed and integrated into Valero's waste water treatment unit BSRP is exempt from permitting as a RCRA hazardous waste treatment facility. The major equipment components have been proven mechanically reliable in refinery service. The system is inherently safer and can be easily integrated into existing refinery operations.