Background Sheepskins have a high natural fat content, which interferes with the tanning process. In order to avoid stains and dyeing irregularities this fat has to be removed. However, this process requires special treatment of the tannery wastewater, because the waste produced by the degreasing process contains hazardous substances. The majority of modern tanning plants have access to effluent treatment systems whereby fats are separated by filtration. The main challenge today is treatment of the remaining fat. This challenge affects the entire tanning sector as the quantities of fat generated are significant. The current practice is to store the fats in tubs or barrels and have them delivered to an authorised treatment plant for a suitable blanketing treatment. On the other hand, other plants use fish oils to produce greasing reagents for the same sheepskins. In this sense, the grease waste from the tanning process could be used instead of fish oil to produce the greasing reagents for the same skins but at another stage of the skin manufacturing process. Objectives The project objective is the implementation and operation of a demonstration process for the recycling of natural sheepskin fat generated by degreasing operations in tanning plants. Tanneries that work with sheepskins must carry out an environmentally problematic operation: degreasing of the skins. To eliminate as much of the natural sheepskin fat as possible, the process involves various degreasing stages, during which waste waters with a high pollution load are produced. Most modern tanning plants have an effluent treatment system where fats are separated by filtration, generating a fat residue. This residue has to be stored in tubs or barrels and must be delivered to authorised treatment plants for suitable inertisation treatment. The quantities of fat generated are very significant, posing a significant problem for the whole tanning sector At INQUIMICA, a process using raw material such as fish oils was previously used. The company considered the possibility of using the residue of natural sheep fat as a raw material in the manufacture of chemical products for the skins sector (shoes, leather goods, etc.), in partial replacement of high-cost raw materials such as fish oils. Using the residue generated in the tanning sector to obtain products to be used in final stages of skin treatment would greatly add to the efficiency of the production cycle. At the same time, INQUIMICA S.A. can produce a lower cost raw material. With this project the beneficiary was able to develop a process for recycling the natural sheepskin fat generated in degreasing operations in certain tanning plants. The actions for the implementation and validation of this demonstration process are: • To develop the technology of sulphatation of fish oil with an SO3 index of 6 percent to be used as a vehicle of absorption of recyclable fats. • A study of the composition of samples of natural grease coming from various tanning industries, in order to determine the optimum regulation conditions. • Trials of the products in which this natural grease can be used, establishing the appropriate percentages of use and formulating the various types of lubricants. • Application trials of the products obtained on skins, to evaluate their qualitative parameters. • Design of the stages of the fat recycling process and scaling up to industrial level. • Implementation, adjustment and operation of the demonstration plant. Results This initiative has enabled the partial replacement of an expensive raw material – fish oil – in the formulation of lubricants for tanning. The beneficiary has recycled 80 tonnes of grease during the year 2003, and once the facilities are fully optimised the grease recycling capacity will be 700 tonnes per year. The beneficiary has produced three products using recycled raw material. The final product can be sold at the same price as the one manufactured without recycled material, guaranteeing a financial return on the cost of the project. The beneficiary forecasts a saving of EUR 450,000/year. For the time being, INQUIMICA has two suppliers of the sub-product who provide it on a regular basis, and is about to sign new contracts with other fat suppliers. The transferability of this process to other European companies could lead to the annual recovery of 1,000 of tonnes of grease, which has been classified up to now as waste. Export opportunities with countries such as India have even been opened up. It will even be possible to supply higher quality final products to more demanding markets. As the project goes on, additional extended applications with greater added value will be researched. This project has been selected as one of the 24 "Best" LIFE Environment projects in 2004-2005