ENV-09-29 Impact of Wet Scrubber Blowdown on Refinery Biological Treatment

Description:

The impacts of FCCU wet scrubber blowdown on refinery wastewater biological treatment BOD/COD removal kinetics; nitrification kinetics; activated sludge process performance; clarification and sludge thickening; and aeration basin and clarifier system operation are discussed. Purge water treatment and denitrification strategies to mitigate the impacts of high sulfite and nitrate loads on treatment performance and the nutrient balance are described. Increased effluent suspended solids caused by floating sludge from denitrification in the final clarifier and high dissolved solids loads on the aeration basin are evaluated along with increased nutrient loads on the receiving water and the potential for H2S formation in the clarifiers because of high sulfate levels in the plant discharge. The impact of a high monovalent-to-divalent cation ratio on activated sludge properties, and control strategies to mitigate the effects of high sodium loads on the clarification and sludge thickening capacity of the activated sludge process are discussed.