Pollution
Humain
Environnement
Economique

In a vegetable oil factory, during a period of heavy rain, the level of rainwater in the retention basin of a sulphuric acid tank had risen rapidly, reached the tank’s vent and blocked it. This tank, which supplies sulphuric acid to the paste grinding process, was in operation. The extraction put the tank into a vacuum and caused it to rupture; 20 m³ of acid spilt into the retention basin. The tank, the transfer pumps, measurement instruments and the retention basin’s protective resin liner were damaged. The area was marked out, and the 28,180 tonnes of liquid waste held in the retention basin (water + sulphuric acid) were pumped out by a specialised company over a period of 2 days. The property damage was estimated at 63,000 euros, and waste removal costs were on the order of 25,000 euros.

The Inspection authorities for classified facilities were informed. The tank’s vent had been extended into the retention basin to prevent acid fumes from spilling out and splashing in the event of an accidental overflow. The operator replaced the damaged equipment with identical components but ensured that the vent did not drop below the edge of the retention basin.