The tanning district of Santa Croce sull’Arno is one of the largest tanning areas in Europe with over 250 tanneries. Its purification system is considered one of the most efficient in the world, always keeping up with the latest scientific and technical knowledge.

From the point of view of environmental respect, the flagship of the Tuscan tanning sector is undoubtedly the Aquarno purifier, a centralised system at the service of the leather district, active since 1974, which today is at the centre of an impressive connection project of the purification system, the so-called “Tubone” which aims to integrate the civil and industrial purification of 42 Tuscan Municipalities.

The new purification system, result of a specific “Program Agreement” between the Ministry of the Environment, the Tuscany Region and municipal administrations, is underway. The possibility of recovering treated wastewater is one of the most interesting results that will bring “Tubone”.

“The new integrated system – explains the president of Assoconciatori, Alessandro Francioni – will redistribute “refined” water directly to tanneries, which no longer have to emit water from the subsoil. Soon we will only use recycled water to tan our hides in a perfect circular economy” says the Tuscan businessman. Do you have no fear about the final leather quality?: “The ongoing experiments give us full confidence in the result – continues Francioni – Thanks to the industrial aqueduct we will actually be able to count on a more constant refined water that will also improve the tanning process”.

In the last forty years the Aquarno water treatment plant has undergone a continuous structural and technological evolution, with the aim of minimising environmental impacts and guaranteeing increasingly higher purification efficiencies. Thanks to continuous investments in research and innovation, it is considered one of the best purifiers in Europe. The system is not limited to the de-pollution of all waste waters produced by the tanning pole, which are released clean in rivers; the purifier is connected to a treatment and reduction system of muddy materials resulting from the treatment that processes them to be reused in other sectors, such as in the construction industry. It is also important to remember that the chromium used in the tanning processes is returned to companies through a careful recovery process (carried out by the Consorzio Recupero Cromo). Even residues and scraps of leather processing – fleshing, splitting and shaving – are recovered and destined for other uses, such as scientific and cosmetic ones.

In over forty years of plant history, the area dedicated to purification has progressively expanded to an area of about two square kilometres; this expansion was accompanied by an equivalent increase of treatment volumes, going from around 10,000 cubic metres in 1974 to over 150,000 current cubic metres, destined to further increase thanks to the interventions planned for the next decade and which will raise the volume threshold to 180,000 cubic metres. There are two distinct treatment lines inside, one for civil waste and one for industrial waste.

The Santa Croce water treatment plant is managed by the Consorzio Aquarno (a non-profit society founded on the initiative of tanners with the partnership of the municipality of Santa Croce) which constantly collaborates with major research institutions, university departments and other accredited companies in order to always test new plant solutions that further reduce sludge production and odor emissions, as well as to improve and make the purification yields even more effective.