Abstract
The effectiveness of odour emission reduction in a municipal solid waste landfill leachate reservoir was evaluated using hexagonal-shaped HDPE cover elements. A previous study conducted in 2020 identified H2S as the dominant contributor to odour emissions from the leachate reservoir, accounting for 99% of total odour units (O.U.). To mitigate these emissions, HDPE hexagonal covers were installed over the leachate basin in 2024. The performance of this system was assessed by analysing changes in H2S concentrations. New measurements carried out in 2025, using Radiello diffusive samplers as in the previous campaign, showed that H2S concentrations decreased from 0.8–1.1 mg m?³ in 2020 to 0.09–0.14 mg m?³ in 2025, after installation. By applying odour thresholds to the measured concentrations, odour units were determined, revealing a reduction from 1129–1609 O.U. to 128–198 O.U. This corresponds to an average decrease of 87.8% in measured concentrations and associated odour impact. Numerical modelling using the TAPM dispersion model was applied to estimate emission factors, incorporating meteorological conditions to ensure a consistent comparison between 2020 and 2025 data. The modelling results confirmed a substantial emission reduction, estimated at 86.2%. Overall, the use of hexagonal-shaped HDPE elements to cover leachate basins in municipal solid waste landfillshas proven to be a highly effective solution for reducing odorous emissions.
