Geotechnical performance index to validate landfill cover efficiency: Cleaner production and circular economy in the Brazilian semi-arid region

The efficiency of landfill cover layers in gas retention is vital to mitigate environmental impacts, reduce biogas modeling uncertainties, and promote resource circularity and low-carbon transitions. This study applies the Geotechnical Performance Index (GPI) to evaluate the spatial relationship between geotechnical properties and greenhouse gas (GHG) emissions in a landfill in northeastern Brazil. The data was obtained through laboratory testing of the soil from the site, in situ testing at 21 points in the cover layer and physical-mechanical characterization of the soil. The GPI included parameters such as moisture (w), degree of compaction (C), dry density (γ d ), void ratio ( e ), porosity ( n ) and degree of saturation (S). Interpolate the data using QGIS®, I'Moran to analyze the spatial correlation and Global Warming Potential (GWP) analyzes. The CH 4 concentrations, of the 21 points analyzed, 95% registered average values of less than 4% v/v. The main CO 2 hotspot had a flow of >300 g.m -2 .d -1 , while for CH 4 it was 39 g.m -2 .d -1 . The GPI was suitable for assessing the efficiency of the landfill cover layer, showing positive spatial correlations with CO 2 (Moran's I = 0.105) and CH 4 (Moran's I = 0.064) fluxes. Under conservative, moderate and optimistic carbon-pricing scenarios (CO 2-eq ), annual revenue estimates amounted to USD 63,285, USD 189,855 and USD 632,850, respectively, which highlights the economic leverage of methane-oriented interventions. The contributions demonstrate that landfill cover performance arises from coupled geotechnical, environmental, and biogeochemical interactions; targeted interventions can therefore elicit integrated responses and strengthen decision-making for landfill management and climate change mitigation. • Novel index evaluates landfill cover efficiency in gas emission control • Geotechnical parameters mapped to reveal greenhouse gas spatial patterns • Improved cover performance reduces emission hotspots in landfills • Spatial analysis links soil properties to greenhouse gas mitigation