The mass arrival of pelagic sargassum is an international issue that is currently taking its toll on the economic activity of affected regions by causing a significant reduction in investment and tourism. The purpose of this work was to evaluate the Logistic Modified and Gompertz Modified sigmoid kinetic models for describing the lag phase in the generation of biomethane. The case studies were: anaerobic co-digestion (ACoD) of Sargassum spp./domestic organic waste and Sargassum spp. in mono-digestion. The experimental method, based on biochemical methane potential (BMP), enabled kinetic models to be built for methane production under environmental conditions and an estimate to be made for the duration of the lag phase. The maximum cumulative production determined for monodigestion was 140.7 cm³ of CH₄/g SV at 99 days, and for ACoD, it was 161.3 cm³ of CH₄/g SV at 172 days. The lag phase was determined to be approximately 7 days and 93 days, respectively. It was concluded that the modified sigmoid growth functions are a valuable tool for studying the start-up and scaling of systems for the ACoD of organic waste. The results present the ACoD of coastal pelagic sargassum algae and domestic organic waste as a potential alternative energy source.

The use and transformation of biomass into highly valuable products is a key element in circular economy models. The purpose of this research was to characterise the volatile compounds and the temperature at which they are emitted during the thermal decomposition by pyrolysis of algal biomass while looking at three different types: (A1) endemic microalgae consortium, (A2) photobioreactor microalgae consortium and (A3) Caribbean macroalgae consortium. Furthermore, the ultimate (CHON) and proximate (humidity, volatile solids and ashes) compositions of the algal biomass were determined. Some volatile species were identified as having potential industrial interest for use as precursors and intermediaries, such as commercially used aromatic compounds which if not suitably managed can be harmful to our health and the environment. It is concluded that the pyrolysis of algal biomass shows potential for the generation of valuable products. The information generated is useful, especially the temperature at which volatility occurs, in order to access the valuable compounds offered by the algal biomasses, and under the concept of biorefinery convert the issue of biomass disposal into a sustainable source of raw materials.

The amount of sargassum seaweed washed ashore on the beaches of Africa, Brazil, Central America and the Caribbean has increased to the point where it has become a social, environmental and financial issue. This research evaluates the potential for Sargassum spp. of the Mexican Caribbean coast to be used in the production of biomethane by estimating: a) stoichiometric methane production (SMP), b) biochemical methane potential (BMP) and c) biodegradability index (BI). The use of a sigmoidal model generalized to substrate to inoculum ratios is proposed, to predict the biomethane production during the anaerobic digestion (AD) of the sargassum. The information obtained shows the seaweed’s potential for biomethane production and will be useful for estimates and scaling when implementing energy harnessing systems for sargassum in the Caribbean. The use of biomass is a key element in the move towards a circular economy. It is hoped that the use of technologies like AD leads to the integration of this seaweed into an economic value chain, thereby reducing the adverse effects of its presence on the ecosystem.

LIFE CYCLE ASSESSMENT OF A TRADITIONAL BRICK MANUFACTURE IMPROVEMENT

This document presents a Life Cycle Assessment (LCA) study to quantify the environmental cradle-to-gate impact of the manufacture of brick for the construction industry, produced with material of igneous source. Its mineral composition and thermal isolation properties were characterized for use in real estate construction. The LCA results for brick manufacture using this material identified the greatest environmental impact to be associated with material extraction and its proportional cement content. Additionally, this document presents an evaluation of the environmental impact of the manufacturing process by comparing traditional fired clay brick and brick of the material under study. In conclusion, the studied material shows thermal insulation qualities and suitability for the manufacture of bricks with low incorporated energy.

The integration of biogas and photovoltaic solar energy systems in sanitary landfills represents a promising strategy for sustainable energy generation and efficient urban waste management. This study evaluates the potential for biogas and photovoltaic energy production in two cells of the Municipal Landfill of Chihuahua, Mexico. Using the LandGEM and MMB models (Landfill Gas Emission Model and the Mexican Biogas Model), biogas generation was estimated by considering the composition of the landfill gas and the characteristics of the cover in each cell, revealing notable differences due to their operational periods and waste deposition. Photovoltaic simulations, conducted with the HelioScope software 2020, evaluated spatial configurations and solar radiation data. The generation potential for 2025 was simulated using predictive models, yielding results between 25.48 and 26.08 MW for the biogas–photovoltaic system, depending on the orientation of the panels and the optimization of the coverage. The novelty of this work lies in the combined evaluation of biogas and photovoltaic potential within a single landfill site, integrating advanced modeling tools to optimize system design. By demonstrating the feasibility and benefits of this hybrid system, the study contributes to clean energy solutions, environmental mitigation, and improved waste management strategies. Our findings emphasize the importance of site-specific management practices and predictive modeling to enhance renewable energy production and reduce greenhouse gas emissions, supporting sustainable urban development initiatives.