Waste tyre generation in South Africa is one of the issues that have not found a sustainable solution. Approximately 1.5 billion tyres are produced annually around the world, and South Africa contributes about 11 million tyres accounting to about 177 835 tons of waste annually. Numerous technologies have been used as possible pathways to recycle waste tyres. This review analyzes the main advances in waste tyre pyrolysis and gasification technologies and lists challenges and successes. For waste tyre pyrolysis, recovering high-value products such as limonene, benzene, xylene, and activated carbon can make the process profitable. For gasification, the objective of new studies is for the producer gas to have a desirable composition for further application in the production of chemicals, heat and power and synthesis of liquid fuels. Also, more research is required to fill the gap in the optimum conditions for solar integrated pyrolysis and gasification of waste tyres. A comprehensive comparative techno-economic analysis of chemicals production from waste tyre via gasification is required to determine the most commercially viable route for tyres.

Automotive paint sludge (APS) is a ubiquitous, recalcitrant waste product of the vehicle manufacturing process. The potential of APS for energy and chemical production via pyrolysis and gasification is undermined by the absence of methodologically consistent, cross‐stream physicochemical characterization. This impedes process design for the valorization of APS. This work aims to rectify that by presenting a direct physicochemical characterization and thermogravimetric comparison of five APS types: electrocoat, phosphate coat, primer, base coat, and clear coat. Thermogravimetric (TGA/DTG) experiments were conducted at three heating rates, i.e., 5, 10, and 20°C/min, under both nitrogen and air atmospheres. The study revealed that the decomposition of APS occurs in three distinct stages. The first stage involves the removal of moisture and the release of volatile organic compounds (VOCs), occurring at temperatures ranging from 30°C to 220°C. The second stage, which occurs at approximately 220°C–550°C, exhibits a further subdivision profile comprising two subsections. This entails the devolatilization stage, which occurs between 200°C and 380°C. Subsequent to this, the cracking of resins, heavy hydrocarbons, and the formation of char occur at temperatures ranging from 380°C to 550°C. The third and final stage occurs at a range of 550°C–800°C, accounts for the least mass loss, and is characterized by the carbonization and decomposition of inorganic compounds. In this work, we have established temperature intervals for drying/VOC removal, VOC recovery, and secondary cracking/carbonization, providing comparative evidence to optimize APS‐to‐energy conversion.

Automotive paint sludge (APS) is a hazardous industrial waste generated during automotive coating operations and is characterized by high moisture content, variable organic and inorganic composition, volatile organic compounds, pigments and heavy metals. Conventional disposal methods, including landfilling and direct incineration, present increasing environmental and regulatory challenges, thereby motivating interest in thermochemical conversion technologies for APS valorization and energy recovery. This review evaluates the current state of research on APS thermochemical conversion through incineration, pyrolysis and gasification pathways. The review compares the major operational characteristics of thermochemical pathways, including reactor conditions, temperature ranges, product yields, energy recovery potential, pollutant formation and downstream cleanup requirements. Also, techno-economic considerations such as drying energy demand and scale-up limitations are discussed. According to the current literature, incineration is the most industrially mature route for APS destruction, whereas pyrolysis offers more flexibility for fuel and material recovery. Gasification shows potential for syngas and hydrogen production but remains insufficiently studied for APS applications. Despite growing interest in APS valorization, a lot of research gaps remain regarding standardized feedstock classification, pilot-scale validation, process integration, environmental risk assessment and techno-economic optimization. Conclusively, future approaches towards managing APS would need to incorporate process optimization for specific APS types, incorporation of co-processing techniques, as well as an overall assessment for both environmental and economic feasibility.

The rapid growth of the population, industrialisation, and technological advancement has increased waste generation in many economies, including South Africa (SA). In 2019, 2020, and 2021, SA generated approximately 11.22 million, 5.90 million, and 10.42 million waste tyres, respectively. As general waste, tyres require proper disposal due to their environmental impact. This study identifies and quantifies traditional waste tyre management strategies in SA and assesses their environmental impacts using life cycle assessment (LCA). The SimaPro software (v9.4.0.2) and ReCiPe 2016 (v1.07) midpoint and endpoint methods were used to evaluate environmental consequences of tyre landfilling, open-air combustion, and exporting. In 2019, an estimated 163,375 tons of uncollected waste tyres was managed through landfilling (51%), open-air burning (4%), and exporting (1%). LCA findings showed that open-air combustion had the highest intermediate and long-term damaging effects on the atmosphere, releasing harmful gases and particulate matter linked to human health carcinogenic risks. Landfilling contributed significantly to long-term human carcinogenic toxicity and freshwater pollution, while exporting posed high resource depletion impacts. This study suggests that addressing waste tyre management challenges in SA requires a shift from traditional disposal methods toward reuse, recycling, and material and energy recovery to ensure more sustainable and ecologically responsible solutions.