Abstract: In the methods for treatment of caustic effluents described in the specification, a spent caustic refinery effluent is supplied to a submerged combustion gas evaporator in which hot combustion gas containing carbon dioxide is injected into the caustic liquid to concentrate the liquid and convert a hydroxide constituent to a carbonate. Where the caustic effluent is from a petroleum refinery, oil in the waste liquid is separated from the aqueous constituent before, during or after concentration.

Abstract: A submerged gas processor in the form of an evaporator or a submerged gas reactor includes a vessel, a gas delivery tube partially disposed within the vessel to deliver a gas into the vessel and a process fluid inlet that provides a process fluid to the vessel at a rate sufficient to maintain a controlled constant level of fluid within the vessel. A weir is disposed within the vessel adjacent the gas delivery tube to form a first fluid circulation path between a first weir end and a wall of the vessel and a second fluid circulation path between a second weir end and an upper end of the vessel. During operation, gas introduced through the tube mixes with the process fluid and the combined gas and fluid flow at a high rate with a high degree of turbulence along the first and second circulation paths defined around the weir, thereby promoting vigorous mixing and intimate contact between the gas and the process fluid.

Abstract: A bustle for use on a flare or an exhaust stack of, for example, a landfill gas treatment system, efficiently transfers gas from the stack to a waste heat recovery system associated with the landfill gas treatment system without substantially affecting the operation of the landfill gas treatment process. The bustle enables the heat recovery system to recover at least a portion of the energy within the exhaust produced by the gas treatment system and to provide the recovered energy either indirectly or directly to a secondary process, such as a wastewater treatment process, to thereby reduce the amount of energy needed to be otherwise input into the secondary process.

Abstract: A waste heat recovery system is coupled to a flare or exhaust stack of, for example, a landfill gas treatment system, to recover at least a portion of the energy within the exhaust produced by the gas treatment system and provides the recovered energy either indirectly or directly to a secondary process, such as a wastewater treatment process, to thereby reduce the amount of energy needed to be otherwise input into the secondary process. For indirect transfer of energy the waste heat recovery system includes a transfer pipe connected between the exhaust stack of a primary process and a heat exchange unit while an induction fan connected to the transfer pipe operates to create a draft within the transfer pipe to facilitate movement of some of the exhaust gas from the exhaust stack of the primary process to the heat exchange unit.