Hunters discovered a fire smouldering at a composting site for both organic wastes and sludge from urban and industrial wastewater treatment plants. The slow combustion reached a 10,000-m3 stockpile of screening rejects (30 x 35 m ground footprint by 7 m high, representing 5 months worth of storage of coarse ligneous parts over 20 mm in size). The operator and emergency services both intervened; 500 m² were removed towards a freestanding sprinkled storage zone.
The fire, though initially brought under control, nonetheless rekindled 9 days later and spread to the ground organic waste in direct contact with the pile. The full array of these materials was then spread into a caterpillar shovel and 2 wheel loaders on a disused parcel; the intact parts were isolated from the ignited parts (individual flame surges due to fresh air input when handling the piles) sprinkled by fire-fighters. The fire was eventually extinguished on 28th November. The extinction water, collected in a 400-m³ basin, would joint the process water discharge channel after compliance verification. The spread mix was then gradually reincorporated into the compost. The November humidity would have triggered an oxidising reaction between screening rejects, composed of 80% dry matter at over 70°C and wet crushed waste, thus causing by means of a temperature rise a self-combustion reaction, or even the self-ignition of wood in certain spots.
The Inspectorate observed a soil and surface water pollution risk due to the sprinkling of ignited piles, as well as on the organic wastes during the intervention period on a non-impermeable zone. A Prefectural emergency order requested an accident report, removal as quickly as possible of the spread materials, as well as the completion within 3 months of an impact assessment study on the soil, groundwater and surface water from the storage of materials spread on the non-impermeable zone.
The stockpile of screening rejects was isolate from the stockpile of crushed organic waste in order to avoid all eventual domino effects. The screening rejects were isolated to limit their static storage duration to 2 months. Should this time limit be exceeded, then the given isolated parcel would be returned and sprinkled. Fire-fighting resources were strengthened by: setting up a lift station capable of being fed from the platform water recovery basin or the fire protection basin, complete with a network of water cannons.
