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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.

Cheese whey is a waste produced in the dairy industry which generates problems if it is dumped directly into the sewer due to its high organic load. An alternative for cheese whey management is anaerobic digestion, a biological process that transforms organic matter into biogas and digestate, two products with significant energy and agricultural potential. This work was aimed at contributing to the building of knowledge about the anaerobic degradation of cheese whey, developing a bibliometric analysis, and tracing trends in related research from 2010 up to the present, using PRISMA® to develop a systematic review based on Scopus® and using Excel® and bibliometric software (VosViewer® and RefViz®) for the identification of information. Our results show that the research around cheese whey is relatively recent and that the highest percentage of publications is from 2018 onwards. Twelve variables of the anaerobic cheese whey degradation process were identified and grouped into five factors: substrate, reactor configuration, digestate analysis, microbiological analysis, and inoculum. Likewise, it was identified that most of the anaerobic processes allow the implementation of the circular economy into the dairy sector. In conclusion, the application of anaerobic digestion in the dairy sector can help to close the productive cycles, produce biofuels, and reduce pollution.

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