The fallout from the Derrimut chemical fire continues. Melbourne Water has received and continues to treat 12 million litres of contaminated firewater at its Western Treatment Plant (WTP), the equivalent of six Olympic swimming pools.
Head of the WTP at Melbourne Water, Kris Coventry, said, “The chemical fire may be old news, but treating the contaminated firewater will take a month.”
Melbourne Water staff worked onsite at Derrimut with the Environment Protection Authority to support the removal of 12 million litres of contaminated firewater runoff into a nearby sewer connected to the WTP.
“Having chemicals like hydrocarbons – diesel, oil, gasoline – coming to a treatment plant is always a better outcome than letting them go into a waterway,” Mr Coventry said.
Over the course of a month, the water will undergo aeration and decontamination through a series of lagoons at WTP containing microorganisms that remove hydrocarbons.
“The micro-organisms are a complex microbiota of bugs that literally “chew up” the hydrocarbons in the contaminated water as part of a treatment and recycling process that is entirely natural,” Mr Coventry said.
The biogases emitted from the process will be captured and converted to energy to power the WTP and feed the grid.
After treatment, the water will be used for non-drinking purposes (agriculture and industry) or safely discharged into the bay.
Onsite at Derrimut, physical barriers like sandbags, plugs and booms remain in place at key creek locations to remove pollutants from the water.
Absorbent ‘booms’ float on the creek’s surface to absorb fire debris, fuels and oils, and concrete drains are being flushed, hot-washed, or pressure-washed to remove remaining pollution deposits.
Melbourne Water said responding to pollution incidents is a necessary but avoidable part of its role as a custodian of Melbourne’s waterways and catchments.
Melbourne Water has responded to 113 waterway pollution events since 1 July 2023, including 13 fires in factories or commercial premises.
Image: nd700/stock.adobe.com
