Introduction Sialkot, a small city in Pakistan, is exporting leather products mainly to Europe. At present there are approximately 248 tanneries in the city, out of which 169 are small, 79 are medium and 9 are large. But all these tanneries are scattered and have poor or zero waste management planning. Solid wastes such as fne leather particles, residues from numerous chemical discharges, reagents from different waste bodies, feshing residues, large pieces of leather cuttings, trimmings, solid hair conglomerates, shavings and remnants of paper bags originate during all stages of leather making [1]. Approximately 850kg per 1000kg is generated as solid waste in leather processing, and just 150kg of the raw material becomes useable leather. Waste generated in the tannery consists of 57-60% feshing, 35-40% chrome shavings/chrome splits, 5-7% skin trimmings and 2-5% hair [2]. Over 80 per cent of the organic pollution load, biological oxygen demand (BOD) emanates from the beam-house (pre-tanning); much of this pollution load comes from degraded skin and hair material. Anaerobic digestion (AD) is a breakdown of complex organic matter by microorganisms in absence of oxygen [3]. Nevertheless, anaerobic digestion is an economical and eco-friendly technique for the production of biogas from different industrial wastes [4]. Hence, Pol. J. Environ. Stud. Vol. 29, No. 5 (2020), 3621-3628 Original Research Biogas Synthesis from Leather Industry Solid Waste in Pakistan Madiha Ijaz 1 , Amtul Bari Tabinda 2 , Sajid Rashid Ahmad 1 , Waheed Ullah Khan 1 *, Nasim Ahmad Yasin 3 1 College of Earth and Environmental Sciences, University of the Punjab, Lahore, Pakistan 2 Sustainable Development Study Centre, Government College University Lahore, Pakistan 3 Senior Superintendent Garden, University of the Punjab, Lahore, Pakistan Received: 8 January 2019 Accepted: 2 July 2019 Abstract About 80% of raw material of the leather industry ends up in waste, which poses a great problem for waste management. During the current study, economical and ecofriendly techniques for conversion of tannery waste into biogas were evaluated. Fats, shavings and dried sludge showed 50%, 65% and 61% organic content and 68%, 45% and 9.6% moisture content, respectively. Dried sludge, pre-tanning waste (fats and shavings) and manure were digested either alone or in different combinations through amber glass bottles. The temperature was maintained from 32ºC to 35ºC by insulating digesters with sand at pH 6.8 to 7.5. The maximum amount of biogas (1623±26.1 ml/kg) was observed by digesting equal proportions of manure and dried sludge. The results depicted that 473±9.19 ml of biogas was biosynthesized from 1kg of sample comprising 25% pre-tanning waste and 75% manure. Keywords: organic waste, biogas, tannery waste management, home scale digester, manure *e-mail: waheedenviro@gmail.com DOI: 10.15244/pjoes/110444 ONLINE PUBLICATION DATE: 2020-04-22