Evaluation of the U.S. EPA-recommended approach to predicting air emissions from pulp and paper industry landfills

There is growing indication that the pulp and paper industry will be required to comply with Clean Air Act (Title V) requirements to estimate emissions of bulk gases and hazardous air pollutants (HAPs) from landfills. One method for estimating such emissions involves the use of the Landfill Air Emissions Estimation Model (LAEEM), which was developed and calibrated specifically for municipal solid waste (MSW) landfills. There is concern about the applicability of LAEEM because the nature of materials placed in industry landfills is considered to be different from that of materials in MSW landfills. As a result, emissions from industry landfills will likely be lower than model predictions. This study examined the basis of LAEEM and its calibration, and explored alternative predictive approaches. The authors concluded that LAEEM, when defined in terms of the default Clean Air Act, or AP-42, factors, does not accurately represent uncontrolled methane and HAP emissions from industry landfills. It does not account for the attenuating effects of biodegradation and adsorption, nor does it account for the potentially slower migration of landfill gas through a fully saturated landfill zone or the oxidation of methane migrating through landfill covers. With adjusted calibration factors that are based on field observations, LAEEM may provide more realistic estimates of methane and HAP emissions from industry landfills.