As part of the real estate construction programme of Place du Grand Ouest in Massy, south of Paris, encroaching water had to be pumped out and treated. Analysis and diagnosis revealed pollution with zinc, chrome, and trinitrophenol (potentially explosive picric acid) in the groundwater, along with possible suspended solids.
The treatment required a continuous flow of 6m3/h for six months.
Based on the data provided, REMEA put together the following treatment regime:
- Installation to trap suspended solids using a sand filter
- Treatment to improve the COD by oxygenating the water
- Precipitation of the zinc
- Correction of the pH, which was strongly acidic. This was neutralised using a base that does not produce any precipitate
- Trapping heavy metals by filtering and flowing over ion-exchange resins
- Capturing picric acid (trinitrophenol) by absorption in active carbon