Development of Engineered Biochar Cocktails for Odor Removal in Composting Facilities

This technical report evaluates the development of engineered biochars and blended “biochar cocktails” to reduce gaseous emissions and odors from commercial composting facilities. Conducted under the Waste to Fuels Technology Partnership 2019–2021 Biennium, the research explores production conditions that enhance biochar’s ability to adsorb compost-related air pollutants.

Twelve biochars were produced from wheat straw and Douglas fir biomass at different pyrolysis temperatures, with nitrogen and magnesium doping treatments to modify surface chemistry and adsorption properties. Each biochar was characterized using elemental and proximate analysis, gas physisorption testing, Fourier-transform infrared spectroscopy, and pH analysis. Adsorption experiments measured capacity to capture hydrogen sulfide (H₂S), ammonia (NH₃), and carbon dioxide (CO₂), with additional work underway on methane and nitrous oxide.

Results indicate that adsorption performance depends on surface area, pore structure, nitrogen content, and functional groups. Findings support further exploration of tailored biochar blends as a potential tool to mitigate compost facility odors and reduce harmful emissions.