Estimate of the Decay Rate Constant of Hydrogen Sulfide from Drywall in a Simulated Bench-Scale Study

Research was conducted to investigate the impact of particle size on H2S gas emissions and estimate a decay rate constant for H2S gas generation from the anaerobic decomposition of drywall. Three different particle sizes of regular drywall and one particle size of paperless drywall were evaluated. The experiment was conducted in a carbon-limited environment. The paperless drywall generated significantly less H2S gas than regular drywall at the same particle size. No significant differences were found between the rates of H2S gas generated from the different particle sizes of regular drywall investigated (p = 0.44), which most likely was the result of the carbon limitation. The volume of H2S gas emitted from drywall was modeled as a first-order decay with correction factors that take into account the impacts of pH, temperature, and liquid-gas partitioning. The first-order decay model resulted in an average decay constant value of 0.14 +/- 0.01 and 0.031 year(-1) for regular and paperless drywall, respectively, using a theoretical gas generation potential of 124 m(3) mg(-1). Although the proposed model is unique in terms of taking into account the impact of gas-liquid phase partitioning, and the pH on the volume of H2S gas emissions, H2S generation and emission from construction and demolition (CD) landfills are influenced by many other factors for which the writers do not account. Thus, more research is needed to accurately predict H2S emissions from CD landfills. Nonetheless, the presented model offers a tool to landfill owners and engineers to estimate a baseline volume of H2S gas that may be emitted from landfilled drywall. DOI: 10.1061/(ASCE)EE.1943-7870.0000609. (C) 2013 American Society of Civil Engineers.