Removal of chromium (VI) from groundwater, Milan (Italy)
Groundwater purification system for chromate removal.
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Location
Milan (Italy)
Client
Land redevelopment companies / real estate companies
Parameters
- Flow rate: 10 m3/h
- Inlet concentration of Cr(VI): 200 micrograms/liter
- Outlet limit value of Cr(VI): 5 micrograms/liter
- Sand filtration with automatic backwash system
- Redox and pH measurements
- Inlet concentration of Cr(VI): 200 micrograms/liter
- Outlet limit value of Cr(VI): 5 micrograms/liter
- Sand filtration with automatic backwash system
- Redox and pH measurements
Performance period
Since 2024
Chromium (VI) levels above the limit values were detected in the groundwater of an old tannery in one of Milan's historic industrial areas. In September 2024, ZÜBLIN Umwelttechnik set up a water treatment plant to convert chromium from the hexavalent to the trivalent form by adding an iron-based reducing agent. To accelerate the reduction, the pH value of the water is kept below the neutral point. The dosed excess iron is then oxidized and filtered before the filtered water is discharged.
Special features
- Reduction with FeSO4 (20 %)
- pH control with H2SO4 (20 %)
- Oxidation with microbubbles and Na(OH) (30 %)
Scope of services
- Chemical delivery
- System maintenance
- Data logging
- Remote access