Background The tanning industry is an industry that can potentially become a source of pollution. It is significant that “the tanning of hides and skins” is listed according to Article 1 of the European Directive 96/61EC (IPPC Directive) as an activity for which integrated prevention and control of pollution has to be achieved. The wastewater produced by European tanneries is treated in many different ways. There are cases in which an individual plant applies the Best Available Technology (BAT) on site, whereas in other situations only pre-treatment, partial pre-treatment or no treatment at all is applied, sending the effluent to a communal treatment plant. The European tanning industry processes 240 million m2 bovine hides per year. This is the equivalent of approximately 1.6 million tonnes of raw hides per year, leading to a sludge production of 320,000 tonnes and a sulphate discharge of approximately 250,000 tonnes per year. The treatment of these wastewater streams also results in an enormous consumption of chemicals and energy. Objectives The “TANEFTREAT” project aimed to demonstrate and disseminate the effectiveness and efficiency of a new compact and integrated plant for the treatment of waste produced by the leather tanning industry. In order to present an alternative to BAT, the project aimed to significantly reduce the use of certain dangerous products in the tanning process, cut down the levels of sludge and CO2 produced, improve the cost-benefit ratio and reduce water consumption by recycling. The project would be experimentally implemented at the Hulshof Royal Dutch Tanneries. The results would also be widely disseminated to other European tanning industries, as well as to the food, textile and paper processing industries. The new process included a combination of process integrated and end-of-pipe measures. Process integrated measures would be undertaken in order to separate the different waste streams generated in the tannery. The end-of-pipe process consists of an anaerobic pre-treatment (Chemical Oxygen Demand - COD - breakdown and sulphate reduction), followed by a sulphur bioreactor (sulphide and sulphate is transferred into elementary sulphur) and two reactors for nitrogen removal (partial nitrification and Anammox technology). Sludge is fermented in order to reduce its volume. Biogas is produced in both the anaerobic pre-treatment and the sludge fermentation. The project expected to: - Realise a “significant reduction” of the impact of the Hulshof tannery on the environment - Make Hulshof a ‘better than BAT’ operating tannery - Improve BAT for the tanning industry regarding wastewater treatment - Ensure that at least 50% of the European tanning industry would be informed about this new technology and its operational as well as economical advantages - Inform other target groups (food, textile and paper processing industry) of the new technology. Results The new wastewater treatment plant is up and running. The project made good progress, but experienced significant technical difficulties, leading to delays and higher investment and operational costs than originally foreseen. Despite these difficulties, most of the objectives of the project were met: Results showed: - COD removal was better than expected and better than BAT. (The project achieved a 95% removal rate, whereas the BAT is >90% - Sulphur removal showed considerable improvement. However, this will be further optimised (The project achieved: 70% removal rate, whereas the BAT is 40% removal rate - Chemical use was better than expected. (The project achieved a reduction compared to the BAT of about 80%) - Energy use was comparable to the BAT. However, more sulphur is removed with the same amount of energy, and net energy use is better than BAT because biogas from the installation is used to produce the energy for the installation - Cost / benefit ratio was significantly better. Exploitation costs of the installation, although higher than foreseen, were 35% lower in comparison to the BAT. The process has good replication possibilities for the tannery sector and for other industries with comparable wastewater characteristics (e.g. food industry). The beneficiary is in talks with the IPPC Bureau and the tannery working group in order to ensure that it will qualify as a BAT once the original BREF* document for the tannery industry is revised later in 2007. Finally this project is a winner of the Best LIFE-Environment projects 2006-2007 awards * The current BREF for the tanning industry (“Best Available Techniques for the Tanning of Hides and Skins”) was adopted in February 2003. See http://eippcb.jrc.es/. This project has been selected as one of the 22 "Best" LIFE Environment projects in 2006-2007