Document Type : Research Paper
Università degli Studi Mediterranea di Reggio Calabria, Department of Civil, Energy, Environmental and Materials Engineering, Via Zehender, loc. Feo di Vito, 89122, Reggio Calabria, Italy.
Adequate waste management is essential not only to ensure healthy living conditions but also to mitigate climate change. Accordingly, the research on developing strategies to boost the circularity of waste management systems is ongoing. In this context, two waste streams are concurrently managed to recover energy and materials in the present study. Specifically, real leachate collected from a full-scale mature landfill site was preliminarily treated through active filtration to remove inhibitory substances partially and then tested, at the laboratory scale, as a nutrient solution for semi-continuous anaerobic digestion of a carbonaceous substrate represented by market waste. The results demonstrate that, at an organic loading rate of 1.0 gVS∙L-1∙d-1, the process was impossible without using the nutrient solution, while the nitrogen present in the pretreated leachate could balance the carbon content of the market waste and provide the system with the necessary buffering capacity, ensuring process stability. The average methane yield (approximately 0.29 NL∙gVS-1) was satisfactory and consistent with the literature. Despite the increases in both the organic loading rate (up to 1.5 gVS∙L-1∙d-1) and volume of added pretreated leachate (up to 100% of the dilution medium), the process remained stable with a slightly lower methane yield of 0.21 NL∙gVS-1, thanks to nitrogen supplementation. The potential use of produced methane as a renewable energy source and residual digestate as fertilizer would close the loop of managing these waste streams.
- Recovery of mature landfill leachate (MLL) from a full-scale landfill was explored.
- MLL was pretreated to prepare it for further use in anaerobic digestion (AD).
- Pretreated MLL was used as a nutrient solution for the AD of market waste.
- The process irreversibly failed in the reactor without MLL addition after 47 d.
- MLL allowed a successful AD at an increased organic loading rate of 1.5 gVS∙L-1∙d-1.