On Friday at 8:20 p.m., a fire broke out on the feeder ram of the furnace feed hopper at a non-hazardous waste incinerator. The employees, alerted by the fire alarm, attacked the fire while waiting for the firefighters to arrive. The firefighters drowned the household waste feed chute to prevent the flames spreading from the furnace to the hopper. They extinguished the fire with 3 m³ of water before finally leaving at 11:15 p.m. The site was shut down and its power supplies were cut off. The firewater was drained to the extraction room and then on to the industrial water pond (provided for such purpose) to be reused in the process. The incinerator was monitored over the weekend. The general power cut caused the flue gas treatment system to turn off. Gases produced by combustion of the waste on the furnace’s grate were discharged untreated during the power cut.

Material damage consisted of:

• gaskets on the hydraulic ram;
• feed hoses;
• check valve;
• 5 m of electrical cable with positioner;
• the ram’s sealed enclosure, which buckled and blackened from the heat.

After the furnace was repaired, it was fully inspected and put back in service two weeks later.

The specific type of waste inside the furnace caused it to overheat and halt the supply of household waste. This heat then travelled up to the waste reception grate, where it heated the household waste waiting at the feeder ram. The heat continued on to the sealed enclosure, housing the feeder ram. However, a hydraulic leak has occurred at the non-return valve mounted on the ram of the feeder. The valve had become loose, probably from vibrations on the hydraulic system (fatigue). Although the oil used was flame retardant, it ignited on contact with the hot parts of the feeder, creating the fire. The resulting smoke that filled the room triggered the alarm.

Following the accident, the operator:

• replaced the feeder ram’s hydraulic hoses by rigid pipes;
• moved the non-return valve to an area away from the feeder ram and strengthened the pipe attachment system with conical fittings.

At the next shutdown, it plans to install a control system to shut off the hydraulic unit when a slight change in the oil level inside the tank is detected so that oil leaks can be identified and stopped more quickly.

Another fire had occurred at the site a few weeks earlier (ARIA 49441).