Pollution
Humain
Environnement
Economique

In an automobile equipment factory, a 5-m³ leak of hydrocarbons polluted the NOUE ROBERT watercourse. A 48-m³ underground tank filled for the duration of maintenance and cleaning operations, due to electrophoresis from draining a surface treatment bath, had caused this leak. This tank was located some 30 cm above a pipe entering the factory’s wastewater treatment plant. The operator drained the tank, whose contents were discarded as waste by a specialist firm, and then plugged the section of pipe nearest the tank. The next day, the operator cleaned the inside of the tank using a high-pressure washer. The effluent created was gradually pumped and also eliminated as waste. In addition to a tank crack, the operator noted pipe deterioration (over a 60-cm² surface area), most likely due to works carried out in the vicinity. Analyses were conducted on 3 piezometers placed adjacent to the tank, on both the upstream and downstream stretches. These devices did not display any values to conclude that the pollution was spreading via groundwater. Aqueous discharges were also sampled in the factory’s discharge line: they revealed no special colour alteration or foul odour. The Inspection Authorities for Classified Facilities asked the operator to inventory all on-site tanks not equipped with a retention basin or double-walled shell as well as to plan on installing a turbidity meter with an alarm relay around the site’s effluent pipeline.