The Geo-tube is a 35 metre long, 2.5-metre wide bag that treats wastewater taken from the Dissolved Air Flotation unit (DAF 2), a refinery unit that separates oil from the water. The water is pumped into the Geo-tube bag and then drains out through small pores in the Geo-tube. After about 14 days a dry sludge is left behind that can be recycled.
Extensive trials of the Geo-tube have found that it is reducing significantly the amount of waste that needs to be removed and disposed of from site, with excellent environmental and financial benefits.
“The old process, involving large, open concrete settling bays, was inefficient. The waste material tended to hold more water, particularly if it had rained, and this meant we were disposing of large amounts of water as well as the waste itself. Each month 18 loads were removed for further treatment and then deposited as landfill,” Geoff Ellison, Refinery Manager, Shell Geelong Refinery says.
“With the Geo-tube we envisage that, in the future, almost all the dried sludge will be taken to the refinery’s composting site, Schoe Park. We are currently trialling a bioremediation process at Schoe Park that uses microorganisms to treat green waste collected by council and oil-contaminated soil and break down any undesirable substances contained. Our long-term vision is to see this waste
recycled into compost, which can be used around trees in the refinery’s green buffer zone,” Mr Ellison says.
The water that drains from the Geo-tube is returned to the DAF unit until oil has been removed, and then sent to Barwon Water for reprocessing. After further treatment some of the water is reused at golf courses and market gardens while the remainder is discharged to Barwon Water’s ocean outfall at Black Rock.
“In addition to being economical to set up and better to look at, the use of the Geo-tube will more than halve the cost of waste disposal faced by the refinery for this particular area. Given these advantages we’re looking at other possible applications across the refinery,” Mr Ellison says.
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