School of hard Knox

GCM Enviro’s technology has helped the Knox Transfer Station significantly boost its efficiencies with a cost-effective trommel screen.

The Knox Transfer Station in Melbourne’s east is more than just a local tip. It’s a facility that focuses on reducing the amount of waste that gets sent to Victorian landfills while acting as a local recycling centre.

It provides the community with a focal point for disposal, servicing locals from five different councils. The facility sets itself apart by embracing the idea that one man’s trash is another man’s treasure, embodied by its recycled goods store and its waste derived fuel production.

To create the fuel, the team at the transfer station has employed a Terra Select Trommel Screen T60 from GCM Enviro.

Craig Davis, who has spent almost 12 years working with screeners, works at the Knox Transfer Station and says he was impressed by the technology on offer from the T60.

Knox trialled a few different types of screeners before settling on the Terra Select Trommel Screen T60 because of its large capacity and focus on waste.

“We’ve had the machine for about two months now and we’ve found it very cheap to run. We go through about six litres of fuel for one hour of processing, which has been really cost effective,” he says.

“Thanks to less moving parts, you don’t need to use as much grease and there’s much less maintenance necessary too.”

Craig says the transfer station is using the machine to produce the perfect particle size for its waste derived fuels.

“We’ve trialled it with brick rubble and concrete rubble. The particle size is important because we need it to be just the right size. If it’s too coarse then it’s difficult to turn to a fuel.

“Currently the T60 is processing hard waste including plastics, foams, timber particle boards and laminates to turn into fuel. It’s handling around 20 tonnes an hour, six hours a day,” Craig says.

Hard waste collected at Knox Transfer Station is first grinded twice to break it down and ensure it’s a finer material.

Craig explains that this is then processed through the T60 to make sure the particle size meets the correct specifications, before being baled and loaded up to send out.

The Terra Select Trommel Screen T60 has a high throughput rate, with a trommel length of 5500 millimetres and 2200 millimetre diameter, with screening capabilities of up to 200 cubed metres an hour.

It’s also equipped with a 4.4 I Perkins engine and is able to be used in a fuel-efficient manner at 1650 rotations per minute.

The machine has a low energy intake and can use power reserves to operate additional equipment such as lock-washer screens or aero-separators. An auger on the outside of the trommel avoids screening material becoming stuck between the trommel and the sidewalls of the machine.

The T60 has a simplified control panel display for operation, with all the important information able to be displayed, and allows operators to program for precise adjustments.

Craig says the new computer system has been of significant benefit, giving operators more control over the machine.

“You can change the computer to feed more depending on how much pressure the trommel has in it. You can also increase and keep your throughput. Because it’s computerised, the T60 can constantly remain fed which helps the flow and keeps the product at the correct particle size,” he explains.

Craig says that the machines have helped to reduce costs, with the screening process improved by 40 per cent and reaching 60 per cent for bricks and soils.

Craig says the ability to change trommels has become much quicker and user friendly.

“Normally, the process of changing a trommel could take up to two hours. With the T60, we’re able to change one in about 20 to 30 minutes. It’s also just easier to reposition it as well,” he says.

“It’s pretty simple to clean, all the guarding comes off and there’s plenty of room to get into it and clean. Compared to different types of trommels, the T60 is much faster to get cleaned properly.”

Craig says the team at Knox were very happy with the T60’s boost to efficiency, with another one ordered and on the way.