The lack of adequate sanitation in Brazil overloads the health system and causes deaths. The utilization of sewage sludge hinders advancements in water treatment. This study aimed to assess the feasibility of producing briquettes by blending sewage sludge with Pinus sp. sawdust. The sewage sludge was sourced from a water treatment facility, while the Pinus sp. sawdust was obtained from a sawmill. Elemental analysis, proximate analysis, and calorific value were evaluated for both biomasses. Briquettes were manufactured using a hydraulic press, varying the proportion of sewage sludge from 0% to 95%, followed by thermogravimetric analysis. Pinus sp. sawdust exhibited higher carbon, oxygen, and hydrogen content, whereas sewage sludge contained more nitrogen and sulfur. The sawdust had greater fixed carbon content, volatile matter, and calorific value, while the sewage sludge had higher ash content. Samples with higher sewage sludge content showed better thermal resistance, with 100% sewage sludge retaining 63.3% mass after exposure to 950 °C. Briquettes with higher sewage sludge content had increased energy density. Considering the elevated nitrogen, sulfur, and ash content, sewage sludge should be limited to 5% in briquette production with Pinus sp. sawdust. This research underscores a significant avenue for sewage sludge utilization and sustainable bioenergy production.

This study explores a circular economy approach in charcoal production, utilizing combustion gases from the process itself to optimize efficiency and quality, minimizing waste and reducing emissions. The research investigates the pre-drying of Eucalyptus sp. wood with these gases before carbonization, through an innovative system that directs gases from the carbonizing furnace to a separate drying furnace. Wood samples were dried at 120 °C and 150 °C for 15, 22.5, and 30 h before carbonization. The analysis included the gravimetric yield of charcoal, semi-carbonized wood, and fines, in addition to evaluating key charcoal properties. Results demonstrated that drying with combustion gases at 150 °C increased the charcoal yield by 7%, regardless of drying time. Furthermore, this pre-drying improved charcoal quality, raising fixed carbon content from 74.68% to over 81% and reducing volatile matter from 24.40% to below 18%. These findings highlight that the utilization of combustion gases for wood drying not only significantly enhances the efficiency and quality of charcoal production but also contributes to the reduction in greenhouse gas emissions, promoting a more sustainable and environmentally friendly alternative compared to conventional methods.

Brazil is the world’s largest coffee producer, resulting in the production of 1 kg of husk and 0.5 kg of parchment for every 1 kg of coffee beans. Given the large amount of biomass and the constant need for energy production, this study raises the possibility of using waste for pellet production. Samples of coffee husks and parchment were characterized by moisture content (dry basis), proximate analysis (volatile matter, ash and fixed carbon), calorific value, elemental analysis, and thermogravimetry, and the pellets were characterized by moisture content (dry basis), bulk density, energy density, mechanical durability, percentage of fines, and hardness. The results were compared with the ISO 17225-6. The parchment had a higher carbon, 49.5%, C/N 45.1%, and lignin 26.2% and lower ashes 2.8% and extractives 14.2%, resulting in higher calorific value, while coffee husks obtained 46.5%, 26.3%, 24.6%, 5.5%, and 34.3%, respectively. Pellets produced with parchment had a higher density 622 kg/m³ and lower moisture content 10.5%, resulting in higher energy density. The parchment pellets met all the parameters of the ISO 17225-6, while the coffee husk pellets did not meet the parameters for moisture, which is less than 15%, and bulk density, greather than 600 kg/m³. Both types of biomass showed potential for pellet production, with further studies needed on coffee husks.

Forest operations consume a large amount of fossil fuels. Storing wood in the field reduces the weight of the wood, optimizing transportation and reducing fuel consumption. However, there are few studies linking these variables. The objective was to evaluate the drying of logs with different diameters and assess the fossil fuel consumption considering the mass of dry wood transported. Eucalyptus logs were divided into two diameter classes: 6 ≤ D1 ≤ 11 cm and 11.1 ≤ D2 ≤ 14 cm. These logs were arranged in a stack, divided into base, intermediate, and top positions, and subjected to drying. The wood moisture values were correlated with the amount of transported dry wood, fuel consumption, and costs. These calculations were based on a vehicle with a load capacity of 41.6 Mg, a fuel consumption rate of 1.82 L/km, and a road cost of 0.51 R$·Mg⁻¹·km⁻¹. The moisture content was lower in smaller-diameter logs located at the top of the storage stack and higher in larger-diameter logs in the intermediate position and in both diameter classes at the bottom position after 365 days of drying. Storage for 365 days, on average, increased the dry wood transport capacity by 90%, resulting in similar gains in fuel economy and the final cost of transportation. Storing wood outdoors has proven effective in reducing its moisture content, resulting in lower fossil fuel consumption during forestry operations, reducing environmental impact, and generating economic gains.