Background The leather tanning process produces waste by-products equivalent to 50% of the raw material by weight. Approximately half of this is used to produce fertilisers and biostimulants. However a considerable part is not re-used or recycled. The disposed of tannery waste has significant environmental impact due to its high content of protein, containing nitrogen in a bioavailable form and other substances that have significant impact on plant metabolism. Leather tanning processes also cause volatile and particulate emissions into the atmosphere. In addition, tanning wastewater presents significant management challenges. Around 1.91 kg of chemical products are used for the treatment of each square metre of animal hide. In Italy alone – which accounts for 62% of EU leather production – this equates to 47 000 kg of chemical products per year. Around 31% of this volume is hazardous substance according to the European Dangerous Substances Directive (67/548/CEE). Tanning wastewater must therefore be suitably treated and controlled for suspended solids, COD, total N, NH3, Cr III, sulphides, chlorides and sulphates. Most of the sludge resulting from tannery wastewater purification treatment is considered hazardous and is sent to landfill. Objectives The GREEN LIFE project aims to develop new technologies to reduce the environmental impact of the leather processing industry. It specifically plans to introduce an enzymatic and oxidative liming process to produce leather of the same quality, with reduced environmental costs. Use of an enzymatic and oxidative liming process hopes to avoid the use of harmful and toxic substances - such as sulphides and soluble chromium - in the tanning treatment process. This will correspondingly reduce the volume of harmful waste by-products – such as solid waste containing chromium and sulphates - emerging from the process. It will also reduce the volume of unwanted hazardous emissions to the air. The system will incorporate recovery of at least 20% of the used water volume for recycling back into the liming process. This will reduce water consumption as well as reducing the volume of wastewater. The demand on wastewater treatment facilities will be further reduced due to the reduced contamination of the water. The project hopes to improve the selective recovery of by-products with industrial or agro-industrial value. This will not enable the valorisation of this waste stream, but reduce the quantity of solid waste sent to landfill or for additional treatment. Expected results: A 100% reduction in consumption of soluble chromium in the treatment process; A 100% reduction in solid waste by-product containing chromium; A 75% reduction in generation of sulphates as by-product; A 20% reduction in water consumption; Reduction in the volume of wastewater to be treated and its contamination load; Reduction in unwanted emissions going into the atmosphere, including elimination of almost all odour emissions caused by sulphuric acid; and Recovery of 12-15% of the biomass – by dry weight – entering the system for valorisation, particularly in agriculture, and corresponding reduction in the quantity of solid waste going to landfill.