The MORGON and SAONE streams were polluted at around 7 am by wastewater from a dyeworks following the rupture of a cast iron pipe. This pipe transported the wastewater collected in the sump to the effluent pre-treatment plant. Shutting down the sump pumps reduced the leak but caused the establishment’s wastewater system to load then the pit to overflow via a pipe that was not listed on the plant’s drawings towards the MORGON stream. The company shut down certain machines to reduce the production of effluents which dropped from 150 m³/h to 75 m³/h. To carry out the repairs, the manager hired a pump and pipes to transport the water from the pit to the pre-treatment basin located 300 m away. As the quantity of pipes was insufficient, the tank’s water was discharged into the rainwater network leading into the MORGON stream. The damaged section of pipe was replaced and the repair was completed at around 9 pm.
The effluent collection and treatment installations and the pipe’s protection using a concrete slab limiting external hazards had been installed in 2001. An assessment was requested in order to detect any defects within the metal structure of the section and check the compatibility of the pipe’s material with the effluents collected and its method of operation (significant load in order to transport the water to the 7-m high pre-treatment basin, possible pressure surges when loading the pipe with intermittent activation of the pumps). The connection between the polluted effluent sump and the natural environment had to be eliminated and the sump had to be equipped with a high level detection system. The company had already caused contamination of the MORGON stream. It had to organise specific emergency resources (pumps, pipes, etc.). No death of fish was noted, and the main impact was colouration of the environment.
The operator had to supply a report on the causes of the accident, the environmental impacts and the measures taken to prevent it from happening again. An updated drawing of all of the effluent collection networks was requested. The pipe had to be adapted to the existing constraints.
