Investigation underway after Avonmouth waste explosion

At approximately 11.20 am on Thursday, December 3, fire service, ambulance and police were called to the scene and a major incident was declared. It is believed that an anaerobic digester containing biosolids was the cause of the explosion. A fifth person suffered injuries but is not thought to be in a life-threatening condition.

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Photographs from the scene showed a silo with extensive damage to its upper section and roof. Anaerobic digesters use bacteria to break down waste, producing methane gas in the process. As the name suggests, however, oxygen is not meant to be present, reducing the risk of an explosion from the flammable methane, which is generally siphoned off and used to generate electricity. The remaining biosolids can then be used as fertiliser.

“Waste is generally fed in at the top of the reactor and methane drawn off at the top,” explained Tony Ennis, director of risk assessment firm Haztech Consultants. “The spent waste can be used as soil improver in agriculture, and the methane is often used to drive a gas engine to generate electricity.