Methane potential and degradation kinetics of fresh and excavated municipal solid waste from a tropical landfill in Colombia

Abstract

The optimization of degradation processes and the management of leachate and biogas produced in landfills are key aspects for the establishment of more sustainable municipal solid waste (MSW) disposal in developing countries. In this study, biochemical methane potential (BMP) tests were used to evaluate CH 4 production potential and degradation kinetics of fresh waste (FW) and five-year aged excavated waste (EW) samples from a tropical controlled landfill with compositional characteristics of developing countries. BMP tests with reconstituted samples of the biodegradable fraction of both MSW types were performed at three substrate/inoculum (S/I) ratios (0.3, 0.5 and 1.0 g VS substrate g − 1 VS inoculum), and CH 4 generation parameters were determined using the first-order and modified Gompertz kinetic models. After 30-d, the best BMP results were reached at S/I ratios of 0.5 and 1.0, with cumulative CH 4 productions of 528 and 433 mL CH 4 g − 1 VS for FW, respectively; and 151 and 135 mL CH 4 g − 1 VS for EW, respectively. The first-order kinetic model provided a good fit to BMP results for FW, whereas the modified Gompertz model showed a better adjustment to the BMP data for EW. Calculated first-order CH 4 generation rates for FW and EW were in the range 0.19-0.36 and 0.23-0.25 d − 1 , respectively. These results evidence the high biodegradability and CH 4 potential of FW disposed of in a tropical landfill in Colombia and the reduced BMP of EW despite a relatively short period after disposal under conventional landfill operation conditions.

Seasonal methane emission from municipal solid waste disposal sites in Lagos, Nigeria

“…Sandoval-Cobo et al 31 stated that fresh waste disposed of produces more biodegradability and methane generation potential than excavated waste. However, methane generation is assumed to start immediately after the deposition of the waste, but in reality, this is not the case.…”

Evaluation of Leachate Recirculation as a Stabilisation Strategy for Landfills in Developing Countries

“…Biogas production had an early onset in both bioreactors (Figure 3); however, by day 45 when the highest biogas generation rates were recorded, the cumulative production of CH 4 in Br2 was 7.2 times greater than in Br1. This phase of intense biogas production coincided with the period of the greatest reduction in organic matter in the leachate (COD and VFA), indicating that under the improved conditions of moisture and temperature, EW constituted an easily assimilable substrate [46,55].…”

“…The solid waste characterisation was performed at the beginning and end of the experiments and included measurement of moisture content, total solids (TS) and VS according to APHA (2012) [53], cellulose and lignin based on the method of Van Soest et al (1991) [54] and TOC using a continuous flow analyser (Skalar San Plus 5000 system). The BMP was determined by the manometric method, following the procedure described by Sandoval-Cobo et al (2020) [55], whereby 59.8 g of EW was incubated with granular sludge from an anaerobic digester receiving wastewater from a cattle and pig slaughterhouse. A substrate to inoculum ratio (S/I) of 1.0 g VS substrate g −1 VS inoculum was used, tests were carried out in triplicate, monitored for 30 days and blank reactors (only inoculum) were run to discount the contribution of the inoculum to CH 4 production.…”

An evaluation of final disposal alternatives for municipal solid waste through life cycle assessment: A case of study in Colombia

“…The region has an average temperature of 21.3 °C and average annual rainfall of 1,597 mm but due to the presence of a bimodal period of precipitation in Colombia, the monthly rainfall can increase 150-300 mm during the rainy seasons. A further description of the landfill site could be found in investigations described by Sandoval-Cobo et al, (2020)…”