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This paper presents the direct combustion with energy recovery as a treatment method to wet waste (waste mixed and contaminated with organic fractions) generated from the selective collection in Brazil, based on its thermochemical characterization, searching for a final destination different from dumps, and decreasing the waste amount sent to landfills in the country. The energy recovery potential was calculated from the physical, chemical, and thermal characterization of products found in the waste stream grouped into five combustible categories (Organic matter, Sanitary waste, Paper/cardboard/Tetra Pak®, Plastics, and Textiles). The thermochemical characterization, the waste's behavior as a feedstock for energy power plants, the energy recovery potential, and GHG emissions avoided from three scenarios of electric power efficiency (18, 25, and 30%) were studied. The results show that the combustion with energy recovery could be used as a treatment method because of the Brazilian MSW characteristics as a solid fuel, such as a lower heating value of 7.22±1.76 MJ.kg−1, moisture content of 49.19±10.05%, and an ash content of 14.23±6.71%; highlighting that in some regions of the country, there is the possibility of using auxiliary fuels for waste combustion. In this way, MSW combustion facilities could contribute an additional 3% of electrical energy to the national energy matrix from the use of at least 67% of the MSW collected. Furthermore, annual emissions of about 1 million tonnes of CH 4 (24 million tonnes of CO 2 -eq) and around 140 million cubic meters of dumps could be avoided, dependent on the gross electrical efficiency used in Waste-to-Energy technology. • Direct combustion with energy recovery is proposed as MSW treatment method in Brazil. • The energy recovery potential and avoided GHG emissions were estimated. • Thermochemical characterization of wet MSW for energy recovery was performed. • The behavior of wet waste as a feedstock for energy power plants was studied. • Energy recovery from wet waste could add 3% to the Brazilian electricity matrix. [ABSTRACT FROM AUTHOR]

Sugarcane straw (SCS) represents about one-third of the total primary sugarcane energy. Since its burning in pre-harvesting periods has been banned in Brazil, SCS available amount has grown, and the development of valuable applications for this lignocellulosic material became crucial for the development of a circular economy. An attractive and current alternative is its application in combustion processes for energy generation. However, in the biorefinery concept, the SCS processing as a potential feedstock for the obtainment of bioproducts and biomaterials, such as ethanol, xylitol, biogas, enzymes and oligosaccharides, has also attracted a great deal of attention. Thereby, this work provides a comprehensive review of the progress of SCS processing aimed at its valorization through the production of high-value products and the development of environmental-friendly and cost-effective processes. Image 1 • Sugarcane straw presents interesting composition for sustainable processes. • Sugarcane straw availability has increased in Brazil due to changes in sugarcane harvesting. • Its composition varies according to material-collection location, weather conditions, plant development period, and variety. • It can be used as feedstock to produce bioenergy, biofuels, composites, and as adsorbent. • Exploration of sugarcane straw as feedstock in biorefineries is still few reported. [ABSTRACT FROM AUTHOR]

The influence of the lignin macromolecule composition, extractives, volatile matter (VM), and fixed carbon (FC) contents on the reactivity and easiness of wood combustion is not fully understood, especially concerning species from fast-growing plantations. This study aims to close this scientific gap revealing the wood chemical composition effects on the combustibility of Eucalyptus clones. Moreover, we proposed new quantitative indexes that allow suitable grouping of genetic materials for energy purposes. The lignin, acetone-soluble extractives, VM, FC, and ash contents, as well as the ratio syringyl (S)/guaiacyl (G), were determined. The thermogravimetric analyses provided the combustion parameters. The characteristics that most contributed to the grouping of Eucalyptus clones were energy productivity (GJ ha−1 and GJ tree−1), energy density (GJ m−3), acetone-soluble extractives (% based on dry mass - db), VM (% db), and the maximum rate of combustion (% min−1). Clones with G units ≤20 g kg−1 db, acetone-soluble extractives ≤1.0% db, and FC ≤ 16% db had easier ignition and better reactivity during the burning. Clones with VM/FC ratio ≥5.0 showed maximum combustion rate ≥8.0% min−1 and acetone-soluble extractives ≤1.1% db. The findings of this investigation are useful to managers' decision-making and contribute to the selection and rational use of the wood for energy purposes. Image 1 • The acetone-soluble extractives reduced the wood reactivity during the combustion. • Lignins with a higher proportion of guaiacyl units decrease the fuel reactivity. • Slight changes in proximate composition can influence the Eucalyptus combustibility. • The higher volatile matter content is correlated with the better fuel reactivity. • Woods with extractives content ≤1.0% and FC ≤ 16% presented easier ignition. [ABSTRACT FROM AUTHOR]