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ZLD for steel industry wastewaters

By 18 June 2021acr, case, mining, rvf

The customer
A multinational company, globally recognized as the leader in stainless steel. Its wide range of flat and long products are applied to all types of industrial applications, from automotive, to building and infrastructure, to energy, etc.
With over a century of history and experience in metals and a local presence spread in all continents, it boasts the widest product portfolio in the market.

The customer’s needs
For his Mexican manufacturing unit producing stainless steel flat products, the customer aims at a ZLD solution. They want the distillate to be recycled in the process with the RO permeate that comes from the pre-treatment of the stainless steel pickling waste water.

The solution provided
The solution consists of 4 evaporators  RV F 60, with a distillate production capacity of 60 ton/day each, followed by 6 AC R 6, with a distillate capacity of 6 ton/day each.

EVALED® RV F is a range of mechanical vapor recompression evaporators designed to achieve the most reliable heat exchange with the minimum fouling and scaling. The line is dedicated to water separation and possible reuse from high salty wastewater (ZLD).

EVALED® AC R is the series of hot/cold water evaporators/crystallizers with scraped heat exchanger surface. This series is designed to treat wastewater containing a high concentration of suspended and dissolved solids and, for this reason, they are always the right choice when a second further step of concentration is needed.
The evaporator produces a recyclable distillate, free of dissolved salts, and a solid or semisolid concentrate with a water content lower than 15%.
If a thermal energy surplus is available on site, AC R evaporators can also utilize steam as a heat source (cogeneration).

EVALED®️ RV F and AC R evaporators can be remotely monitored and controlled through the HUBGRADE/EVAlink digital platform.


The solution achieved

  • Water recovery: ~85% 
  • Concentration factor: ~7 times
  • Distillate recycled to the manufacturing process
  • Cost reduction for solid salt slurry disposal
  • ZLD

Our client obtained a pay-back benefit in 2 years.

Technology type Material Footprint (m2)
4x Mechanical Vapor Recompression RV F 60 UNS S32750 4x 20.9
6x Hot/cold water scraped AC R 6 UNS S32750 6x 9.9
Parameters U.M. Waste In Distillate Out Concentrate
pH 6.5-8.8 6.5-8.5 7-9
TS at 105 °C % 8-14 - <85
Conductivity μS/cm 15000-60000 <100
Nitric nitrogen ppm 40000-75000 <25
Sulphates ppm 10200-16500 <15
COD ppm 110 <15