Leachate Modelling, Carbon Footprint and Gas-to-Energy Recovery for Sustainable Environmental Management of a Municipal Solid Waste Landfill in Niğde, Türkiye

Leachate and methane are produced simultaneously at municipal solid waste landfills, yet they are usually assessed separately and rarely against what a specific site actually reports. This study builds a site-constrained model of the Niğde regional sanitary landfill at Hıdırlık, Türkiye, which has operated since 2013 for 47 member municipalities and received a reported 445 t of waste per day in 2024. A daily leachate water balance driven by bias-corrected ERA5 reanalysis for 2015-2024 is coupled to an IPCC first order decay landfill gas model and to an operational carbon footprint calculation across five management configurations. Using the footprint of the lot currently in operation, 4.85 ha, modelled leachate generation is 9850 m3 yr−1, equivalent to 0.061 m3 per tonne of waste, of which climatic percolation supplies 30 % and waste-intrinsic moisture the remainder. The February peak of 112 m3 d−1 is 4.2 times the annual mean and requires 7576 m3 of equalisation storage; a 0.6 m evapotranspirative cover reduces the peak by 58 % and the storage requirement by 62 %. Methane generation in 2024 is 2118 t. Reproducing the reported output of 36 MWh d−1 would require a collection efficiency of at least 94 %, which lies above the range supported by field measurement, indicating an installed rather than a sustained rate. The operational footprint falls from 330 to 91 kg CO2e per tonne when improved cover, 65 % gas collection and electricity generation are combined, and gas collection efficiency dominates that result.