Sanitary landfill leachate treatment was evaluated using magnetite-catalyzed ozone, an upflow anaerobic sludge blanket (UASB) reactor, and microalgae, both individually and in combination, to improve biodegradability and remove organic matter, solids, metals, and nutrients. Leachates were characterized before and after each treatment, and their impacts on methanogenic activity, aerobic toxicity, and the BOD₅/COD ratio were assessed. Magnetite-catalyzed ozone pretreatment enhanced biodegradability, enabling an optimal coupling point with the UASB at 40 min when the specific methanogenic activity reached 0.22 g CH₄-COD/(gVSS·d). The UASB achieved COD removal rates of up to 75%, but high concentrations were maintained in the effluent with low ammoniacal nitrogen and phosphorus removal rates. Microalgae promoted nutrient removal, reducing total nitrogen and phosphorus by up to 65% and 70%, respectively, although with lower efficiency in terms of organic matter removal. Process coupling demonstrated that ozonation followed by UASB application improved anaerobic degradation, whereas the use of microalgae after biological treatment optimized the final effluent quality. Despite the improvements achieved, the final values for some parameters still exceeded the discharge limits, indicating the need for operational adjustments or additional treatments to ensure effective purification.

This study evaluated the efficiency of catalytic ozonation with magnetite (Fe₃O₄) in degrading recalcitrant organic compounds in leachates from two sanitary landfills in Colombia. The optimum treatment conditions were also analyzed by means of a response surface design, resulting in 6 g O₃/h, 2.5 g/L Fe₃O₄, and pH 9, which resulted in COD removal rates of 85.3% in El Guayabal and 75.8% in La Madera. Moreover, the BOD₅/COD ratio increased from 0.26 to 0.38 and from 0.23 to 0.32, respectively, suggesting increased effluent biodegradability. The most efficient ozone consumption (2.7 g O₃ per gram of COD removed) was obtained under alkaline conditions with a high catalyst concentration. Magnetite demonstrated structural stability, although its catalytic efficiency progressively decreased after three cycles of use, with COD removal decreasing from 85.3% to 73.6%. These findings validate catalytic ozonation with magnetite as an efficient alternative for advanced leachate treatment, with the potential to optimize contaminant removal in industrial effluents and strengthen environmental remediation strategies.

The study evaluates the generation and recovery capacity of methane at the Villavicencio Landfill in Colombia, using the LandGEM model. It shows a significant increase in methane generation, rising from about 1.5 million cubic meters in 2010 to over 8.5 million in 2020, indicating a growing urgency to implement effective mitigation measures. It was estimated that by the year 2042, the electrical energy production from methane could be 248.067 kW/day, capable of supplying about 43.705 homes monthly. Additionally, thermal energy generation would be 468.572 kWh/day, useful for industrial processes. Management scenarios were proposed, where, for example, operational optimization could increase electric production to 342.333 kW/day, benefiting more than 60.000 homes monthly. The conclusions highlight the direct correlation between the amount of waste and methane generation, and the significant potential for converting these emissions into energy, pointing towards regional energy self-sufficiency and sustainability. Methane recovery represents a valuable alternative to the dependence on fossil fuels and for the development of a circular economy.

Los procesos basados en ozono hacen parte de los Procesos Avanzados de Oxidación que se han aplicado sobre los lixiviados de rellenos sanitarios. Las características altamente tóxicas de los lixiviados de rellenos sanitarios, pueden reducirse por medio de los procesos basados en ozono, los cuales han demostrado alcanzar altas remociones de contaminantes, en especial, de compuestos orgánicos recalcitrantes. En esta revisión se compila información reciente (2015 a 2021) referente a los procesos basados en ozono, donde se ha estudiado la eficacia como tratamiento, se analiza las condiciones óptimas de acuerdo al tipo de lixiviado y al método de tratamiento a emplear. Se identifica la tendencia de implementación como pretratamiento y postratamiento acoplado a procesos convencionales.

Homogeneous photo-Fenton photocatalysis is one of the most widely used advanced oxidation processes in treating wastewater containing pesticides, where optimizing the catalyst dosage and oxidizing agent, with the response being mineralization in terms of total organic carbon (TOC) or removal of the specific contaminant, is the goal of any experimental design. Experimental development in treatment processes necessitates executing a significant number of experimental conditions that require the use of reagents, energy, and execution time. Therefore, modeling such phenomena emerges as an alternative to these limitations in wastewater treatment. In this research, the influence of factors FeSO4 and H2O2, each at three levels, on the mineralization of a synthetic solution of the insecticide Carbendazim (50 mg/L) in terms of TOC was evaluated using a multiple linear regression model optimized by response surface methodology. The main results established that the best model fit considers the interaction between FeSO4 and H2O2 (X1*X2) and the quadratic terms of each (X21,X22) with p-values < 0.05. The validation of the model using the Leave-One-Out Cross Validation (LOOCV) technique, as well as accuracy and precision through residual analysis and ordinary least squares assumptions, confirms the validity of the conclusions derived from it.

El cambio de uso de suelo es una grave preocupación global y un impulsor clave del cambio climático. Este estudio comparó el cambio en el uso de suelo entre San Pedro Mixtepec, México, y San José de Cúcuta, Colombia, utilizando imágenes satelitales de 2000, 2010 y 2021. Se empleó la metodología de Procesamiento Digital de Imágenes de Satélite propuesta por Galindo en 2014, con una clasificación supervisada mediante el clasificador MAXLIKE. Las categorías identificadas fueron forestal, infraestructura y áreas agrícolas. Se validó la superficie forestal utilizando datos del Instituto Nacional de Estadística y Geografía (INEGI) y del Instituto de Hidrología, Meteorología y Estudios Ambientales (IDEAM). Los resultados mostraron daños a los servicios ecosistémicos, especialmente la regulación climática y la biodiversidad, esenciales para el bienestar humano. El cambio de uso de suelo tiene un impacto directo en estos servicios y resalta la importancia de abordar este problema en la agenda gubernamental.