Modeling Anaerobic Digestion Processes to Treat the Organic Fraction of Municipal SolidWaste in a Megacity: A Comprehensive Approach to Sustainable Waste Management

Abstract

The organic fraction of municipal solid waste (OFMSW) represents between 40% and 50% of the solid waste of a megacity and despite its great potential for use, continues to generate environmental problems, which highlights the need to continue the search for sustainable and efficient solutions [1].  Current research processes have been geared towards anaerobic digestion (AD) as a promising technology to treat this waste. To this end, this study focuses on examining variables and mathematical models to precisely implement AD processes in a megacity, while exploring its technical and economic feasibility to address the increased amounts of these wastes, in order to optimize current technological developments.   In megacities such as Bogotá, the case study area for this research paper, addressing the environmental, social and public health impacts generated by OFMSW is of the utmost importance. Anaerobic digestion is projected as an innovative and sustainable alternative, which not only contributes to treating waste, but also as a source of renewable energy, in addition to generating valuable by-products for agriculture. However, successfully applying AD in a megacity requires an in-depth analysis of the processes involved and the examination of multiple variables for its integration into models that become essential decision-making tools. The following are among the technical variables of analysis for these processes and their subsequent modeling: OFMSW composition, temperature, carbon-to-nitrogen ratio, pH, volatile fatty acids and the presence of inhibitors as critical factors that impact AD performance. Given this scenario, having an adaptive approach that ensures predictive and consistent results over time is indispensable. In addition to these variables, aspects associated with economic, environmental, and social viability should be included, such as population size and projections, climate variability and seasonality, costs associated with the comprehensive service, correct separation at the source, policies and governance models, and land use plans established within the development plans of the cities[2]. Thus, the results obtained from this research study will provide a comprehensive understanding of the factors, processes and variables that influence the efficiency of AD of OFMSW in a megacity. These findings will not only contribute to the design of more efficient systems, but also support decision-making processes, as well as the formulation of waste management strategies, policies and practices at the city level. [1]      L. M. Ulloa-Murillo, L. M. Villegas, A. R. Rodríguez-Ortiz, M. Duque-Acevedo, and F. J. Cortés-García, "Management of the Organic Fraction of Municipal Solid Waste in the Context of a Sustainable and Circular Model: Analysis of Trends in Latin America and the Caribbean," Int J Environ Res Public Health, vol. 19, no. 10, 2022, doi: 10.3390/ijerph19106041. [2]       L. Mu, L. Zhang, K. Zhu, J. Ma, and A. Li, "Semi-continuous anaerobic digestion of extruded OFMSW: Process performance and energetics evaluation," Bioresour Technol, vol. 247, pp. 103-115, 2018, doi: 10.1016/j.biortech.2017.09.085.