Nombre: THIAGO MEDEIROS DOS REIS
Fecha de publicación: 17/09/2024
Junta de examinadores:
Nombre |
Rol |
|---|---|
| LAURA MARINA PINOTTI | Presidente |
| MARCELO FERNANDES VIEIRA | Examinador Externo |
| THIAGO PADOVANI XAVIER | Examinador Interno |
Resumen: Coffee production in Espírito Santo plays a crucial role in the local economy, being fundamental to the agricultural and financial development of the region. As Brazil's second-largest coffee producer, the state contributes over 30% of national production, standing out in the production of Arabica and Conilon coffee. The by-products generated, such as coffee husks and grounds, represent a valuable opportunity for energy production. However, the challenge lies in maximizing the utilization of these by-products, which are notable not only for the quantity generated but also for their composition, rich in organic matter and lipids, essential elements in methane production. The valorization of these residues through anaerobic digestion proves to be promising, providing a sustainable disposal method and generating useful byproducts such as biogas for electricity production and organic fertilizer. However, anaerobic digestion faces challenges related to nutrient balance, composition, and the complexity of high molecular weight organic molecules. To address these issues, a 7% sodium hydroxide pretreatment was conducted to increase the biodegradability and bioavailability of the molecules and to verify the potential increase in methane production. In this context, this study evaluated the biochemical methane potential (BMP) of coffee residues through anaerobic co-digestion with food waste. The substrates used included domestic coffee grounds (treated and untreated) and industrial coffee husks (treated and untreated) from a coffee producer in Espírito Santo. The food waste co-substrate was obtained domestically, and sludge from a wastewater treatment plant (WWTP) reactor was used as inoculum. Duplicate batch anaerobic reactors (250 mL) were fed with the substrates in different proportions, using a substrate/inoculum ratio of 1. BMP tests were conducted over 30 days at mesophilic temperature (35±2 °C). The highest BMP levels were detected with 50% treated coffee grounds (400 NmL/gTVS), 50% treated coffee husks (344 NmL/gTVS), and 100% food waste (600 NmL/gTVS). On the other hand, 100% coffee grounds or husks exhibited low BMP percentages (88 NmL/gTVS and 186 NmL/gTVS, respectively), due to the low carbon/nitrogen ratio and pH outside the ideal range. These results indicate that coffee residues have potential for energy recovery through anaerobic digestion (AD), highlighting AD as a promising alternative for valorizing these residues
