Análisis de la generación energética a partir del biogás obtenido en la Planta de Tratamiento de Agua Residual El Salitre (Bogotá)

Treballs Finals del Màster d’Energies Renovables i Sostenibilitat Energètica, Facultat de Física, Universitat de Barcelona. Curs: 2021-2022. Tutor: José María Chimenos Ribera

Wastewater treatment is an important phase of the anthropogenic water cycle. The purification of water has an impact on the quality of life of the populations, settled in the water rounds and downstream of the dumping points. This work relates to Sustainable Development Goals six and seven which focus on clean water and sanitation and affordable, clean energy. An efficient operation of a WWTP (Wastewater Treatment Plant) can contribute to the fulfillment of these, in cities where there is a wide concentration of population and industries such as the capital of Colombia. The Salitre WWTP treats 7m3/s of wastewater from half of the population of Bogotá, has primary and secondary treatment, and sludge treatment is conducted through thickening, mesophilic anaerobic digestion, and dehydration. The biogas from the anaerobic digestion of this process is composed of CH4 and CO2 in smaller proportions. The trace components that are often present in biogas, water vapor, hydrogen sulfide, siloxanes, hydrocarbons, ammonia, oxygen, carbon monoxide, and nitrogen. This document methodologically analyzes technical data of the WWTP, the investments, the current energy expenditure, the potential for energy savings and the emissions made, the production of this biogas and the possibility of improving it to produce energy through cogeneration To convert biogas into biomethane, two main steps are performed: (1) a cleaning process to remove trace components and (2) an improvement process to adjust the calorific value. The upgrade is usually done to meet standards for use as vehicle fuel or for injection into the natural gas grid. In this case, the self-sufficiency of the plant with the available energy of its by-products is sought. Analyzing the current scenario to the potentials, important improvements are obtained in the energy use and the possibility of improving the process with thermal energy that is not currently used. Although high investments that require more funding and government incentives must be made at an economic level, in the long-term taking into account the useful life of the energy recovery systems and the plant as such it is attractive. Finally, from the environmental point of view, this project pursues energy efficiency with self-sufficiency and the significant reduction of greenhouse gases.