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.