Thermal pathways for sustainable waste management: Leveraging leather tannery waste as a renewable energy source

The growing production of consumer goods increases waste generation, challenging disposal systems. The aim of the work was to use real data to propose a closed loop leather production process, so as to eliminate storage and use the potential of thermal processes for energy recovery. Such actions allow for improving the company's economic balance, but above all for a positive environmental impact. The tanning industry generates about 825 kg of waste per 175 kg of finished leather, mostly landfilled at high costs of utilization. This study examines energy recovery from tannery waste in various path: combustion, pyrolysis, and gasification using data from a Polish tannery. show combustion has the highest energy yield (94 %), followed by gasification (75 %) and pyrolysis (43 %). The technological process was analyzed and the potential of the by-products generated was quantified. Offcuts offer the highest energy recovery potential, while tannery sludge is the largest waste mass. Energy-intensive processes such as TAIC, dyeing, and cutting require significant power, with offcuts and shaving waste demanding 66.9 kWel and 31.3 kWel, respectively. Thermal energy from incineration meets heating needs and supports waste drying, while waste heat in an Organic Rankine Cycle (ORC) covers 40 % of electricity demand. This research highlights the benefits of shifting from landfill disposal to sustainable waste management, reducing costs and environmental impact. The proposed calculations demonstrating how engineering can enhance sustainability in the leather industry and others. • Recycling of tannery waste reduces landfill disposal issues. • Physicochemical properties of by-products as an energy source. • Mass and energy balance of tannery waste streams. • Energy from tannery waste combustion for heat and electricity. • Technological process and mass balance in tanneries.