Evaluación de los co-beneficios ambientales y económicos del aprovechamiento energético de las excretas porcinas
This research aimed to quantify and economically value the environmental co-benefits of energy production from swine manure treatment by anaerobic digestion (AD). The study is focused on the environmental co-benefits assessment of anaerobic digestion systems with energy production and biogas flaring...
| Autor: | |
|---|---|
| Tipo de recurso: | tesis de maestría |
| Estado: | Versión publicada |
| Fecha de publicación: | 2021 |
| País: | México |
| Institución: | Universidad Autónoma Metropolitana |
| Repositorio: | Repositorio Institucional de la UAM Iztapalapa |
| Idioma: | español |
| OAI Identifier: | oai:bindani.izt.uam.mx:nv935299n |
| Acceso en línea: | https://doi.org/10.24275/uami.nv935299n |
| Access Level: | acceso abierto |
| Palabra clave: | info:eu-repo/classification/LEM/Refuse as fuel info:eu-repo/classification/LEM/Basuras como combustible info:eu-repo/classification/LEM/Protección ambiental -- Eficiencia de costos info:eu-repo/classification/LEM/Biodegradation info:eu-repo/classification/LEM/Biodegradación info:eu-repo/classification/LEM/Anaerobic bacteria info:eu-repo/classification/LEM/Bacterias anaeróbicas info:eu-repo/classification/LEM/Biogas info:eu-repo/classification/LEM/Environmental protection Cost info:eu-repo/classification/cti/1 |
| Sumario: | This research aimed to quantify and economically value the environmental co-benefits of energy production from swine manure treatment by anaerobic digestion (AD). The study is focused on the environmental co-benefits assessment of anaerobic digestion systems with energy production and biogas flaring in comparison of conventional manure management as reference. Co-benefits are additional effects to the main benefits, they were estimated quantifying environmental effects by life cycle analysis and determining their monetary value by economic valuation methods. Co-benefits were included to cost/benefit analysis determining their effect on the profitability of the systems; for the economic analysis, energy production were considered the main economic benefit. In order to generate greater certainty on the environmental and economic evaluation of the systems, information was obtained from a swine manure with an anaerobic digestion system in operation. A swine medium farm located in the State of Puebla was selected, the farm has an annual average production of 5,000 head of cattle and a manure (faces and urine) production of 2,807 tons per year treated by AD for electricity generation used for self-consumption. Manure has 22.5% of total solids, which 81% are organic matter, they were divided as solid manure and liquid manure in function of their physical state and the technique used to remove them from animal houses. Base on the matter balance, the 59% (sb) of manure is treated by anaerobic digestion and 41% by composting. This farm is an example of Mexican farms at industrial scale which treat their manure by anaerobic digestion. The liquid manure is treated by anaerobic digestion using covered lagoons at industrial scale (> 1000 m3 ) generating biogas, digestate and liquid effluents. The AD system operate with low total solid content of 3.27%, high hydraulic retention time of 162 days, a low organic load at the entrance of 0.16 kg SVT/m3 .day and biogas yield of 1.2 m3 /kg SVT. Electricity of 251,959 kWh was produced annually from biogas supplied 67% of farm energy demand. Digestate and liquid effluents are treated by aerobic methods producing, as subproducts, compost and treated water used to irrigation. The site characterization generated field data for process parameters and matter and energy flows estimation, which were used to simulate alternative systems of manure management for the environmental impact evaluation. Environmental impacts were evaluated by life cycle assessment (LCA) in systems with energy production (partial and total energy production), the standard practices of biogas flaring and conventional management. Energy production systems generated the most significant environmental benefits on climate change, photochemical oxidation, eutrophication, acidification and fossil and abiotic resource depletion, compared to other systems without energy production. The analysis allowed generating important and useful information that contributes to the inventories of LCA of pig manure treatment by anaerobic digestion in Mexico. Problems related to the bad manure management were identified by the sensitivity analysis in the LCA regarding non-intentional emissions during the AD process and its by-products handling. Significant environmental loads are produced for these problems promoting methane emissions into the atmosphere in greater magnitude if conventional practices managed manure. These findings show the importance of a proper operation during the AD process using correct operating procedures and providing technical training to avoid global warming. Environmental effects obtained by LCA were monetized using different economic valuation methods. According the economic valuation analysis, water resources depletion was the impact with the highest economic value of $359 thousands pesos per year compared to others impact categories; eutrophication and fossil resource depletion had annual amounts greater to $200 thousands pesos, meanwhile climate change impacts presented the lowest economic cost of $36 thousands pesos. LCA and economic valuation of environmental effects allowed estimate environmental cobenefits of $350 to $642 thousands pesos per year in the AD systems compared to conventional management as reference. GEI reduction, eutrophication reduction, decreased fossil and water resource depletion and organic fertilizer substitution were the most critical cobenefits. Energy production from pig manure treated by AD requires an initial investment higher than $12 million of pesos; this investment requirement may limit its implementation. It also requires operational and maintenance costs of $550 to $650 thousand pesos per year. According to the economic analysis, equipment’s preventive and corrective maintenance represents 50% of the total O&M costs. Biogas and energy systems produce annual economic benefits of $336 to $618 thousand pesos due to savings for electricity self-consumption mainly; however, they have not economic feasibility in 20 years, even considering financial support by the Mexican Government and Banks. The low profitability was attributed to the low yields during the AD process and the biogas to energy conversion. Economic profitability was changed when environmental co-benefits were included in the cost/benefit analysis; in this case, a process environmentally profitable was obtained with benefits for the environment and the society. Environmental and economic importance of environmental co-benefits of the energy production from pig manure treatment by anaerobic digestion, measured by LCA and monetized by economic valuation methods, were demonstrated in this study. Co-benefits relevance was reflected on the economic-environmental profitability of the systems. These findings provide elements to continue with government funding for anaerobic digestion systems installation in México, but focused on energy production, high efficiency, best-operating practices, and support for technical training. The present study contributes with important and useful information to support the development of public political programs on energy sustainability in the livestock sector; the management and valorization of livestock wastes; and the implementation of climate change mitigation strategies in the agriculture, forestry and other land use sector (AFOLU). |
|---|