Evaluation of the Influence of Operating Parameter Variations in an Anaerobic Co-Digestion Plant for Sewage Sludge and the Organic Fraction of Municipal Waste at Pilot Scale

The increasing generation of organic waste, both solid and liquid, such as sewage sludge (SS) and the organic fraction of municipal solid waste (OFMSW), along with the energy and material demand associated with population growth, drives the search for holistic alternatives for the efficient management of these wastes. These alternatives aim not only at proper waste management but also at harnessing these wastes to meet energy and material needs. In this context, concepts such as the circular economy and biorefineries have gained prominence, with anaerobic digestion (AD) being one of the most relevant biochemical processes, based on the action of a series of microorganisms that enable the degradation of organic matter. This process begins with hydrolysis, where microorganisms secrete enzymes that break down high-molecular-weight compounds such as proteins, carbohydrates, and lipids into simpler molecules like sugars and amino acids. However, this stage is limiting due to the slow degradation rate. Subsequently, during acidogenesis, other microorganisms transform the intermediate products into volatile fatty acids (VFAs), which are used in the final stages to produce acetate and methane gas. Both SS and OFMSW have great potential to be treated through anaerobic digestion. However, anaerobic mono-digestion (AMoD) of these wastes may present limitations, such as nutrient imbalance in the case of SS, or process inhibition due to the accumulation of VFA´s in the AMoD of OFMSW. Anaerobic co-digestion (ACoD), which involves the combination of two or more waste types, emerges as a strategy to enhance process efficiency. This approach helps to regulate nutrient imbalances and optimize operational conditions, improving both methane production and digestate quality. Regarding methane, the goal is to achieve a high conversion of organic matter to CH₄, while ensuring that the digestate meets the necessary safety standards for human and environmental health. The co-digestion of SS and OFMSW represents an intersectoral strategy that integrates wastewater and municipal waste management, reducing costs and promoting a holistic approach. In the last decade, ACoD of both SS and OFMSW has grown significantly, facilitating energy recovery and achieving economic benefits by replacing fossil fuels in the production of heat and electricity. However, a literature review reveals that most studies have been conducted at the laboratory scale and under controlled conditions. Additionally, of all the publications reviewed, only eight correspond to research conducted in Latin America: four in Brazil, two in Argentina, one in Chile, and one in Colombia. This presents significant challenges for the region, as despite the existence of relevant global studies, implementing these results is not straightforward. Environmental conditions, such as temperature, vary significantly. For example, in countries with marked seasons, boilers are required to maintain the temperature of the bioreactors, while in tropical countries, where the temperature is more constant, strict thermal control may not be necessary for good methane production.

• Autores: Pulgarin Muñoz, Carlos Esteven
• Tipo de recurso: Doctoral thesis
• Fecha de publicación: 2025
• Institución: Universidad de Antioquia
• Repositorio: Repositorio UdeA
• Idioma: eng
• OAI Identifier: oai:bibliotecadigital.udea.edu.co:10495/46415
• Acceso en línea: https://hdl.handle.net/10495/46415
• Palabra clave: Sewage sludge; Lodos de depuradoras; Residuos urbanos; Residuos sólidos; Biogas; Metano; Methane; Digestate and Kinetic models; Anaerobic co-digestion; Organic fraction of municipal solid waste; http://id.loc.gov/authorities/subjects/sh85120516; ODS 3: Salud y bienestar. Garantizar una vida sana y promover el bienestar de todos a todas las edades; ODS 6: Agua limpia y saneamiento. Garantizar la disponibilidad y la gestión sostenible del agua y el saneamiento para todos
• Rights: openAccess
• License: http://purl.org/coar/access_right/c_abf2