Biodigestão anaeróbia de resíduos vegetais provenientes de central de abastecimento

• Autor(a) principal: Edwiges, Thiago
• Data de Publicação: 2017
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações do UNIOESTE
• Texto Completo: http://tede.unioeste.br/handle/tede/3029
• topic: Biogás; Metano; Potencial bioquímico de metano; Reator de mistura completa; Biogas; Methane; Biochemical methane potential; Continuous stirred tank reactor; ENGENHARIA AGRICOLA::ENGENHARIA DE AGUA E SOLO

The economical development and urbanization process have contributed to the increase in solid waste generation and problems related to final disposal. Thus, the National Solid Waste Policy reinforces treatment in order to improve efficiency in the management of solid waste as one of its priorities and stimulates to recover and use energy. Anaerobic digestion has been suggested as a promising approach to the treatment of organic fraction of solid waste, mainly because it represents an opportunity to reduce environmental pollution and minimizes impacts concerning the energy crisis. So, this trial aimed at evaluating FVW biogas potential, collected in a wholesale market (Unit from Foz do Iguaçu/PR) through batch and semicontinuous tests. Fruits and vegetables trading from that unit generates approximately 70,500 t year-1, with 2,800 kg d-1 solid waste, composed of almost 85% organic matter. The influence of chemical composition of twelve FVW different samples with different compositions on biochemical methane potential (BMP) was analyzed. The BMP ranged from 288 LN CH4 kg VS-1 to 516 LN CH4 kg VS-1, with significant statistical differences among means. This was explained by in the waste chemical composition over time. BMP variation was most strongly correlated for lipid content and high calorific values (HCV). Linear regression analyses were carried out to develop statistical models to predict as fast as possible methane potential of this kind of waste. The models were analyzed according to chemical compounds and HCV based on simple and multiple regression. The model with the best statistical metrics included lipid, protein, cellulose, lignin, and HCV, with a 92.5% R² and lignin content negatively correlated to BMP. Since HCV and lipids were strongly correlated, and because HCV can be determined more rapidly than chemical composition, HCV may be useful for predicting BMP. In addition to batch tests, the performance of anaerobic digestion was also investigated in a semicontinuous mode using a FVW mixture as a single substrate. The performance of a continuous stirred tank reactor (CSTR) was monitored along with the gradual increase of organic loading rates (OLR) from 0.5 gVS L–1 d–1 to 5.0gVSL–1d–1. BMP of FVW used as a feedstock to CSTR was 370 LN CH4 kg VS-1 with 81% biodegradability. During the whole trial pH was stable and there was an adequate level of buffering capacity in the system. Volumetric biogas production (LN biogas L–1 d–1) increased linearly (R² = 94.4%) according to OLR increase. On the other hand, the specific methane production (LN CH4 kg VS-1) has registered the best performance at an OLR of 3.0 g VS L–1 d–1 and 30 days of hydraulic retention time, with 285 LN CH4 kg VS-1 added, reaching 74% of BMP measured by batch tests. A clear accumulation of volatile fatty acids (VFA) was monitored with a decreased specific methane yield was detected with an OLR above 3.0 g VS L–1 d–1.