The management and valorization of residual organic matter, such as sewage sludge and manure, is gaining interest because of the increasing volume of these residues, their localized generation and the related problems. The anaerobic digestion of mixtures of sewage sludge and manure could be performed due to the similarities between both residues. The purpose of this study is to evaluate the feasibility of the co-pyrolysis of sewage sludge (SS) and digested manure (DM) as a potential management technology for these residues. Pyrolysis of a sewage sludge/manure blend (50:50%) was performed at 525°C in a stirred batch reactor under N2 atmosphere. The product yields and some characteristics of the product were analyzed and compared to the results obtained in the pyrolysis of pure residues. Potential synergetic and antagonist effects during the co-pyrolysis process were evaluated. Although sewage sludge and manure seem similar in nature, there are differences in their pyrolysis product properties and distribution due to their distinct ash and organic matter composition. For the co-pyrolysis of SS and DM, the product yields did not show noticeable synergistic effects with the exception of the yields of organic compounds, being slightly higher than the predicted average, and the H2 yield, being lower than expected. Co-pyrolysis of SS and DM could be a feasible management alternative for these residues in locations where both residues are generated, since the benefits and the drawbacks of the co-pyrolysis are similar to those of the pyrolysis of each residue.

The problems related to the increase in the generation of discarded tires demonstrate the need for profitable, efficient, cost-effective, and sustainable processes for their waste management. In particular, the valorization of pyrolytic solids for energy storage applications is of interest. In this study, four processes were performed: (1) pyrolysis; (2) chemical activation and pyrolysis; (3) pyrolysis and physical activation; and (4) chemical activation, pyrolysis, and physical activation. The process consisting of chemical activation, pyrolysis, and physical activation yielded 52% solid material with the highest electrical conductivity (2.43 Ω^–1 cm^–1) and a surface area of 339 m²/g with an average pore size of 3.6 nm. In addition, it was found that pore size had a greater effect on the conductivity than surface area. Liquid and gas fraction compositions were modified by the presence of chemical activation: aromatization reactions were favored, and limonene was not observed in the liquid fraction, while an increase on the CH₄ concentration caused an increment in the heating value of the gas fraction. It was demonstrated that chemical and physical activation enhance the properties of the pyrolytic solid product derived from waste tires that make it suitable for the partial substitution of materials for electric energy storage applications.

Within the context of the new circular model for wastewater treatment aimed at achieving zero waste, this research seeks an alternative to landfill disposal of waste screenings. It examines the feasibility of thermochemical processes—combustion and gasification—for the valorisation of solid recovered fuel (SRF) derived from screening wastes, which are the only waste in wastewater treatment plants (WWTPs) that typically have an absence of existing recycling or valorisation processes. Laboratory-scale experiments assessed the technical viability of gasification, and energy balances were calculated for both combustion and the syngas obtained from gasification experiments. Results indicate that both processes are feasible for SRF valorisation. Combustion demonstrated the highest energy efficiency, yielding up to 1.6 MJ per kg of raw SRF, compared to gasification’s maximum of 1.4 MJ. The moisture content in SRF feedstock influences both processes, underscoring the need to optimise moisture levels. Additionally, combustion showed a higher conversion efficiency due to the complete oxidation of the feedstock, whereas gasification produced valuable syngas that can be further utilised for energy production or as a chemical feedstock. The study concludes that, from a purely energetic perspective, combustion is the most efficient process for SRF valorisation. However, gasification offers significant environmental and sustainability advantages, including lower greenhouse gas emissions and the potential for integrating with renewable energy systems, making it a more attractive option for long-term sustainability goals.