RESUMEN
A small unit of cogeneration of energy and heat was tested at the Centre for Research and Training on Sanitation UFMG/COPASA - CePTS, located at the Arrudas Sewage Treatment Plant, in Belo Horizonte, Minas Gerais, Brazil. The unit consisted of an engine power generator adapted to run on biogas, a thermal dryer prototype and other peripherals (compressor, biogas storage tank, air blower, etc.). The heat from engine power generator exhaust gases was directed towards the thermal dryer prototype to dry the sludge and disinfect it. The results showed that the experimental apparatus is self-sufficient in electricity, even producing a surplus, available for other uses. The tests of drying and disinfection of sludge lasted 7 h, leading to an increase in solids content from 4 to 8% (50% reduction in sludge volume). Although the drying of sludge was not possible (only thickening was achieved), the disinfection process proved very effective, enabling the complete inactivation of helminth eggs.
Asunto(s)
Fuentes de Energía Bioeléctrica , Biocombustibles , Calor , Aguas del Alcantarillado , Eliminación de Residuos Líquidos/métodos , Reactores Biológicos , Agua , Purificación del AguaRESUMEN
This work aimed at developing a mathematical model that could estimate more precisely the fraction of chemical oxygen demand (COD) recovered as methane in the biogas and which, effectively, represented the potential for energy recovery in upflow anaerobic sludge blanket (UASB) reactors treating domestic wastewater. The model sought to include all routes of conversion and losses in the reactor, including the portion of COD used for the reduction of sulfates and the loss of methane in the residual gas and dissolved in the effluent. Results from the production of biogas in small- and large-scale UASB reactors were used to validate the model. The results showed that the model allowed a more realistic estimate of biogas production and of its energy potential.
Asunto(s)
Reactores Biológicos , Composición Familiar , Metano/análisis , Aguas Residuales/química , Purificación del Agua/instrumentación , Purificación del Agua/métodos , Anaerobiosis , Biocombustibles/análisis , Análisis de la Demanda Biológica de Oxígeno , Brasil , Simulación por Computador , Modelos Químicos , Análisis de Regresión , Reproducibilidad de los Resultados , Reología , Aguas del Alcantarillado/química , Termodinámica , Eliminación de Residuos LíquidosRESUMEN
This paper discusses the main drawbacks and enhancements experienced with the design and start up of two full-scale UASB plants in Brazil. The topics addressed are related to blockage of inlet pipes, scum accumulation, seed sludge for the start-up, corrosion and gas leakage, odour generation and sludge management. The paper describes the main improvements achieved.