News

The new Water-Treatment Plant will incorporate the most advanced Zero Liquid Discharge (ZLD) technology in order to reduce the environmental footprint and improve sustainability.

The new plant will be designed to purify and recycle all the polluted cold complex wastewaters using an advanced treatment method that includes:

- Fenton Oxidation: dosing hydrogen peroxide and ferrous sulphate to obtain radical oxygen able to oxidize the organic content, converting it to inorganic salts, water and carbon dioxide.
The radical oxygen is the most effective oxidant agent to attack and destroy the large organic molecules of color and surfactants.

- Ultrafiltration and Reverse Osmosis: the use of membrane technologies must be designed accurately, estimating the necessary pre-treatment for membrane protection and the most efficient washing system, obtaining the maximum recovery rate.

- Evaporation and Crystallization: water evaporation will be done under vacuum conditions. The concentrate solution is fed into the evaporator and passes across a heat source. The applied heat converts the water in the solution into vapor. The vapor is removed
from the rest of the solution and is condensed while the now-concentrated solution is fed into a second evaporator, and so on. The multistage evaporator consists of three or four sections minimizing the steam consumption. The condensate vapor is recovered and blended with the permeates from RO. The concentrate solution from the last evaporator stage is delivered to the crystallization unit where at the end of the process a sludge of a very low content moisture is obtained.

All the water will be fully reused within the process, as industrial water for the cold complex production and demineralized water for process and steam boilers.
Thanks to Danieli technology, TMZ will save of about 320,000 m3/year of fresh water with a consistent reduction in plant OpEx, and without any liquid discharge to the external environment, as the plant is designed to treat as well the internal liquid waste generated from
the process itself.

Commissioning of the water-treatment plant is expected by the end of 2019.

Main "Plus" of the ZLD Plant

The most evident advantage of this plant is that it is "environmentally friendly".

It makes use of the most recent BAT (Best Available Technology) in steel manufacturing. Consequently, it provides the steelma ker with other subsidiary advantages, such as:

- OpEx savings. The recovered water is used to blend the makeup water, thus improving the quality of the cooling water and achieving consistent cost savings.
- Access to public financing as a green technology.
- No needed for discharge authorization: no risk of delay of plant startup.
- No discharge limit to respect: no risk of production plant stoppage.
- No inlet water shortage: no risk of plant stoppage.
- Finally, the use of this technology reduces the plant's environmental footprint and improves the consideration of the local environment authorities.

For the design of a ZLD recovery plant the critical point is to know well the technological production process and the pollutants, in terms of quantity and quality, added during the production.
For instance, some streams must be treated separately (due to a specific hard pollutant to be removed) or pretreated separately (to minimize the chemical consumption, or to avoid in desiderate chemical reaction.)

Thanks to its complete in-house technologies and the internal collaboration between interdisciplinary departments, Danieli incorporates the fundamental know-how that allows development of a customized process that takes into account the specific requirements of steel production.

The ZLD concept represents the future for the sustainability of all industrial sectors all over the world.

With 200 water-treatment installations worldwide Danieli is the reliable partner with innovative solutions to Give water a second life.