Quantification of landfill gas generation and energy recovery estimation from the municipal solid waste landfill sites of Delhi, India

In this study, estimation of landfill gas (LFG) emission from three existing landfill sites of Delhi such as Ghazipur, Bhalswa, and Okhla was carried out using three LFG generation models, namely, IPCC Default model, First order decay model, and LandGEM. The total estimated methane emissions from all the three landfills was observed till 2030 as 2443.66, 1114.61, and 1642.51 Gg using Default, First order decay, and LandGEM respectively. The average rates of emission from these landfills were found as 20.35, 24.10, and 17.51 Gg/year by IPCC Default method; 18.69, 13.67, 7.59 Gg/year by First order decay model and 9.91, 9.81, 8.40 Gg/year by LandGEM for Ghazipur, Bhalswa, and Okhla sites respectively. The results showed that the Default method overestimated the methane emission due to variable input parameters such as fraction of landfilled waste and methane proportion in LFG. First order decay model provided best possible emission rates with comparatively lesser uncertainty and could relate actual waste deposition practices. LandGEM also provided moderate results of methane emission with significant uncertainties caused by variation in municipal solid waste deposition data, gas generation rate and methane generating potential of waste. Furthermore, Yedla method was employed to quantify energy recovery potential using landfill gas recovery system, which showed 5783.62 TJ energy can be recovered from landfilled municipal solid waste with an efficient recovery system.