Treatment of wastewater from aqueous pickling process
Pickling Water Treatment With Turbevap Vacuum Evaporator
Pickling process for stainless steel can occur differently but in general there are three different types of wastewater that can be identified:
  • Water is used to obtain the correct acidity concentration in the immersion bath; wastewater will be generated during regeneration or pouring in pickling tanks. This type is commonly known as waste acid or immersion waste. Its flow rate will be relatively small but contains a high amount of metal and a high acid concentration.
  • Water is used to wash steel surfaces after bleaching to remove sediment and acid particles. This type will be larger amount but with less acid and metal concentrations than the above type.
  • Water is used to filter air. During the cleaning process, gases containing NOX and F- are generated. In general, they are routed to an exhaust system where scrubbers wash off the fluorosis.

The most serious health and environmental problems associated with wastewater from the steel industry originate from high concentrations of metals such as chromium and nickel. Iron exists naturally in water and has a low toxicity. Nitrate has instead gained more attention because it causes indirect effects on the environment. The rinsing water from the above types is highly acidic; therefore, none of them can be discharged directly into the environment.

Turbevap evaporator is an excellent treatment system in these cases. Pickling wastewater will be treated by evaporation method. The vapors will be condensed and distilled, while concentrated residues such as metal compounds and toxic acids will be deposited. The vapor after being extracted and condensed will return as pure water and can be safely discharged into the environment, as well as reused for production processes.