Spent Caustic Treatment

In the refining industry sodium hydroxide is used to remove sulfur and other compounds from the oil. The “spent caustic” waste stream generated from this process contains high concentrations of hydrogen sulfide, phenols, and a variety of complex organic compounds. These compounds consume large amounts of oxygen and introduce varying degrees of inhibition or outright toxicity to the microorganisms in the refinery’s activated sludge wastewater treatment system (bioreactor). For wastewater systems that nitrify to meet effluent ammonia limits, nitrification can be reduced or stopped altogether in the presence of spent caustic. Often, the inherent inhibitory/toxic nature of the spent caustic waste stream requires expensive, offsite treatment by other vendors.

USP Technologies can chemically oxidize the spent caustic using hydrogen peroxide alone or in combination with an iron catalyst, to dramatically improve the “treatability” of this waste stream.