A Novel Semi-Empirical Model for Multi-Scenario Estimations of Nitrous Oxide Emissions from Municipal Solid Waste Landfills

Landfills contain significant amounts of nitrogenous
substances
and serve as important sources of nitrous oxide (N2O),
with emissions primarily concentrated on the working face. This paper
developed a semiempirical model based on the logistic principles to
simulate the temporal dynamics of landfill N2O emissions.
Results showed that the model successfully captured the S-shaped N2O emission pattern observed at a landfill site (R2 = 0.54). Both field and laboratory data indicated that
the key model parameter λN2O, which represented the rate of N2O emission potential change with O2 availability, was
strongly correlated with waste nitrogen content, landfill operation
practices, and temperature. The model output representative N2O emission factors for three typical landfill scenarioswaste
sorting (WS), business as usual (BAU), and enhanced emission (EE)with
values of 0.51, 5.20, and 10.97 mg N·kg–1 waste,
respectively. Under the BAU scenario, the representative emission
factor was used to estimate historical N2O emissions from
Chinese landfills over the past two decades, yielding a total of 12.25
Gg N. In contrast, WS achieved a 90% reduction in N2O emission
by diverting high-nitrogen waste (e.g., food waste), while EE resulted
in a 111% increase even exceeding those from composting and incineration.
The study demonstrates that that the semiempirical model enables robust
estimation of landfill N2O emissions at both site- and
national- scales. This can supplement the current IPCC guidelines
on greenhouse gas inventories.