Hydrogen Sulfide Emission Properties from Two Large Landfills in New York State

Landfills are a source of malodors, greenhouse gases, harmful pollutants, pests, noise, and litter. To reduce their impact on neighboring communities, landfill facilities and the policies they follow must reduce emissions of trace gases such as hydrogen sulfide (H2S) and methane (CH4). However, a comprehensive understanding of the spatial variability of both pollutants at landfills should first be established to obtain a clear picture of emissions at landfills. This study measured the mixing ratios of H2S and CH4 at two landfills in New York State (Fresh Kills Landfill and Seneca Meadows Landfill) in November 2021 using laser-based methods deployed in a mobile lab. H2S emission fluxes were estimated based on a mass balance calculation. The highest mixing ratios of both H2S and CH4 were measured at Fresh Kills Landfill, at up to 7 parts per billion (ppb) and similar to 140 parts per million (ppm), respectively, yet these values resulted in a low Delta H2S/Delta CH4 ratio, at approximately 5.2 +/- 2.6 x 10(-5) mol mol(-1) and a H2S emission flux of 0.02 +/- 0.01 mg m(-2) day(-1). The highest Delta H2S/Delta CH4 ratio was observed at the Seneca Meadows Landfill at 8.6 +/- 4.3 x 10(-4) mol mol(-1) and yielded a H2S emission flux estimate of 17.7 +/- 12.9 mg m(-2)-day(-1). The variability in mixing ratios and Delta H2S/Delta CH4 ratios measured at the landfills can be attributed to various factors, including facility operations and design, landfill age, meteorology, types of waste, and pH levels, but further multiday measurements are needed at each landfill to improve emission estimates and determine a more accurate and resolute reasoning behind these variations.