CATENOY – FRANCEadmin
Origin of the incident
Historical pollution: leakage in tanks of a chemical plant.
- The product has a high viscosity (honey or semi liquid tar type) and crystallizes in cold weather.
- On a surface of a few acres, a floating layer of chemicals and hydrocarbons with a free phase thickness of up to 7 m originally.
Geography and nature of the terrain
- Agricultural zone
- Limestone (chalk)
Variability of the groundwater
- Average depth of aquifer 22 m below ground level
- Seasonal variability of aquifer between 2.5 and 3.0 m over the year
- ODSI’s solution was implemented after encountering many difficulties using other methods of skimming.
- ODSI installed a pumping unit DS 500-12D (specially equipped for skimming at a depth greater than 8.5 m – practical limit for vacuum pumping) linked to skimmers SKIM 2-25 and SKIM 4-25. A settling and storage unit was later added in order to reduce handling and treatment costs for the pumped product.
- The dynamic vacuum suction technique allowed for the skimming of the viscous free phase to the point of discharge, and reduced the free phase to a thickness of less than 10 cm in all wells.
- Over a period of more or less three years, recovery of 11 m3 of pure product, with an average pure product pumping of 9.5 L/day.
Nb of Wells