Abiotic decomposition of municipal solid waste under elevated temperature landfill conditions

Abiotic decomposition of simulated Municipal Solid Waste (MSW) was investigated for thermal reactions that impact landfill gas components such as methane, carbon dioxide, and hydrogen. The gas composition and temperature were monitored as a function of heating rate and time. The tests were conducted at 483 kPa (70 psig), 55 wt% moisture, and 30 to 60 W controlled heat input in the presence of biological inhibitors. The gas composition trends show that for heat inputs higher than 46 W, the CH4/CO2 ratio diverges from the initial value of 1.0 to as low as 0.2, correlated to a decrease in CH4 concentration. Major findings of the study include that the primary gas composition ratio (CH4/CO2) starts to reduce from the baseline value of 1.0 as the heating rate is increased from 30 W to 51 W and further declines at significantly higher rates beyond 51 W. The hydrogen evolution was directly proportional to the amount of CH4 available in the system. Low levels of CH4 (<25%) correspond to decreased H-2 levels in the system (<5%) whereas injection of CH4 gas in the system correspond with a renewed H-2 generation The study provides insights into the operational conditions such as available heat and moisture leading to changes in landfill gas ratios.

Automated summary

This study investigated the abiotic decomposition of simulated Municipal Solid Waste (MSW) and its impact on landfill gas components. The results showed that the gas composition and temperature were influenced by the heating rate and time. Higher heating rates led to a decrease in the CH4/CO2 ratio, and the release of hydrogen was directly proportional to the amount of CH4 available in the system.