The Sustainable Treatment of Municipal Landfill Leachate

Abstract

In this study, cattle manure was co-digested with different ratios of landfill leachate: 75:25 (R1), 50:50 (R2), and 25:75 (R3) to evaluate the performance capacities of biogas, CH4 production, and the volume obtained from this gas. The methane (CH4) and carbon dioxide (CO2) composition was analyzed using gas chromatography. A positive effect of leachate on methane production was observed in all three treatments when co-digested with cattle manure. It is evident that the highest methane production (CH4) was achieved in R3, reaching values of 96.81% on day 36, while R1 had the lowest methane production with maximum values of 91.74% on day 16. These high methane values in all three treatments can be attributed to the synergistic effect of the mixture, where it is considered that aged leachate has a higher buffering capacity as well as a more acclimated methanogenic consortium, leading to rapid methanogenesis of the organic load. Finally, there is concordance between the volume of biogas generated in R3 and the maximum methane content achieved by the 0.3:1 ratio of landfill leachate and cattle manure used in this reactor. Likewise, the Duncan test applied to the daily volume generated in reactor 3 confirms the maximum biogas volume obtained in this experimentation with a value of 203.67 mL reached on day 16 of anaerobic co-digestion, with 95% reliability. This allows inferring a high potential for the utilization of leachate in circular economy initiatives to address the challenges of achieving sustainability in the efficient management of municipal urban waste.