Closed water cycle for the tanning industry: from waste water to process water.

““AQUARNO - Project co-financed under Tuscany POR FESR 2014-2020”

The ACQUA360 intends to build a pilot plant for the purification and refining of civil waste water, with the aim of producing a sufficient quantity of process water that can be supplied to 3 tanneries representing the Tuscan production sector, to test and validate their use in the whole cycle of tanning, 100% of the productive potential of the company.

The project is preparatory and essential for the design and construction of the industrial aqueduct in the Tuscan tanning sector, already planned according to the agreement between the Ministry of the Environment, the Tuscany Region and local administrations. Before the construction of the industrial aqueduct and the real civil wastewater treatment plant, which will have to supply 18,000 m3 / day of "refined" water to the sector, considering the huge investment to sustain and the environmental, technical and political importance of the initiative, it is necessary to validate the effective re-use of this purified water in the tanning process.

The pilot ACQUA360 will consist of treatment modules for ultrafiltration, nanofiltration, disinfection, cooling and storage of treated water, and then proceed to the procurement of tanneries by tanker with a potential of water treated by the plant equal to 100 m3 / day. Preliminary to this project were the research carried out by some of the project partners on this issue from 2005 to date, regarding the study of the compositional characteristics of a water that can be used within the tanning cycle and the optimization of a refinement process of the civil wastewater, with re-use in the small-scale tanning cycle by tanning companies in some leather processing processes.

The project involves 3 Tuscan tanneries (with different tanning processes), which will test on their real process, the waste water purified by the ACQUA360 pilot plant. In this way it will be possible to validate the water purification process on the basis of the actual feasibility of re-use, highlighting any problems and precautions that must be taken into account in the construction phase of the industrial aqueduct.

The extension of the experimentation to the entire sector and the extended validation will be assured by the tests of the use of the waste water purified by the pilot also on "recipes" and work phases different from those carried out by the partner tanneries, so as to give "robustness" "And greater representativeness to the sector. In this way it will be possible to draw up "guidelines of use" for all the Tuscan tanneries that will be served by the industrial aqueduct. In this way it will be possible to quantify in objective terms of mechanical and chemical-physical performance, as well as "commercial", the quality of the leather produced during tannery tests, compared to the hides obtained in the traditional way.