Treating and reusing wastewater on site
Since 2014, the L’Oréal plant in Settimo, Italy, has been treating its wastewater by evapoconcentration. This technology involves heating the effluents so as to recover, on the one hand, the treated water, which can then be recycled, and on the other hand, the concentrates.
The factory therefore installed the necessary amenities to reuse a heat source already available onsite – the compressors. As a result, evapoconcentration does not consume any additional energy. But another technical aspect inherent to evapoconcentration technology had to be addressed: waste generation. Evapoconcentration produces concentrates to be eliminated, like the sludge from the wastewater treatment plant. So that the overall equation is positive, a portion of the liquid waste to be destroyed (manufacturing losses, non-compliant waste fluids, etc.) is also treated with the evapoconcentrator to recover the water, thereby reducing the factory’s overall waste generation.
By decreasing the load of effluents to be treated, the system also helps improve the efficiency of the site’s water purification plant.
Ten thousand cubic meters of water treated annually
The teams that developed this project have therefore focused on optimising the entire process so that both the environmental equation – dependent upon the water treatment efficiency, liquid wastes, availability of the energy needed, etc. – and the economic equation – based on costs of energy, water, waste treatment, etc. – are positive.
Today, the evapoconcentrator can potentially treat around 30 m3 of water per day, or 10,000 m3 a year. Over the month of January 2015, it already recycled, and therefore saved, 500 m3 of water. When this system is combined with all the wash-water optimisation projects underway, the site’s water-consumption reduction should reach 42% by the end of 2015.