Joseph P. Curro, PE, BCEE

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Wood Waste Combustion Fuels Landfill Leachate Evaporation

Joseph P. Curro, PE, BCEE, Principal, CDM Smith

One method for reducing the volume of landfill leachate that is coming into common use is evaporation of water from the leachate.  Evaporation is accomplished in a system that uses heat input to evaporate approximately 30 – 50% of the water contained in the leachate, thus reducing the volume requiring further treatment or disposal. In most cases, the volume reduced leachate can be reintroduced into the landfill. This can replace the water lost in the landfill gas production reaction and can be a substantial benefit in effecting an increase in landfill gas production where the landfill gas is extracted for beneficial use.  Supplying a source of heat input for a leachate evaporation system can be prohibitively expensive if a fuel, such as natural gas, fuel oil or propane is used. Use of landfill gas can be a viable option. However, at most landfills, landfill gas is extracted for sale, or is not generated in significant quantities proportional to leachate production.  Landfills typically receive large volumes of tree wood (trunks, branches, stumps), as well as construction and demolition wood and wooden pallets. Combustion of a mixture of all types of wood waste as the heat input to a leachate evaporation system can be a viable, cost effective option. A further benefit of utilizing wood waste combustion would be the reduction of wood waste at the landfill, adding the benefit of wood waste disposal through volume reduction.  By burning wood waste in an enclosed combustor and directing the heat of combustion directly to a leachate evaporator, a number of positive benefits can be realized. Along with the obvious benefits of leachate and wood waste volume reduction, emission controls on the wood waste combustor would be minimized since the combustion gases would pass through a tank of leachate which would act as a scrubber for the gases. 

Joseph P. Curro, P.E., BCEE is a Principal Engineer in the Environmental Service Group of CDM Smith and is a leader in the Landfill Services Group. Mr. Curro has over 50 years experience in combustion, waste to energy, incineration, biosolids treatment, leachate handling, landfill gas production and reuse, landfill design and development of innovative, combustion based systems. Mr. Curro is a Registered Professional Engineer in four states and is a Board Certified Environmental Engineer with the American Academy of Environmental Engineers and Scientists.