City West Water's latest resource efficiency success stories include a conveyor belt manufacturer that cut water use by 30% in 12 months, after aiming for less than a 15% reduction, and a tissue-maker that halved trade waste discharges and water consumption.
The Melbourne water utility's latest newsletter also details changes to cooling water testing practices that allowed Mobil to cut water use and trade waste discharges at its Altona refinery.
Rubber hits the road in water conservation efforts
When an audit revealed rubber conveyor belt manufacturer Fenner Dunlop's Footscray facility was using 7.2 megalitres of water a year, the company set a goal of reducing consumption by one megalitre within 12 months.
But the company far exceeded the target, reducing water use over the course of a year by 2.2 megalitres and making further changes that have brought total savings to 2.7 megalitres annually – equivalent to a third of its former usage.
Measures included closing six cooling drums no longer required for rubber curing and upgrading amenities at the factory.
Other actions included fixing leaks, resetting float valves and adjusting boiler blowdown procedures.
Fenner Dunlop found the water savings brought other benefits, delivering a major reduction in energy use and trade waste discharges.
Electricity consumption fell by about 800,000kWh and gas consumption fell by nearly 3,000 gigajoules. Trade waste discharges more than halved – from 79,000 litres a year to 28,000.
Fine savings by tissue-maker
In another case study, installing an $800,000 fines filtration system allowed tissue-maker Encore Tissue to halve water consumption, saving 166 megalitres a year.
The system led to a reduction of 143 megalitres in trade waste discharges – representing almost a 50% reduction.
The system filters paper fibres out of the process water, allowing the water to be reused. The solids can also sometimes be reused in paper manufacture.
Company cold-shoulders excess water use
City West Water reports that Austco Polar expects to save five million litres a year by switching to a closed-loop ammonia condensate cooling system for its Laverton North cold storage facility.
Unlike the previous system, which required water to cool the oil that lubricated its compressors, the new system does not use any water. And because it is gravity-based, the company no longer needs the 7kW pump that used to move water around the site.
Other case studies in the newsletter include Mobil's Altona refinery, which automated testing for total dissolved solids (TDS) in its cooling water circuit.
That means cooling tower water is only drained and replaced when TDS reaches a level that exceeds the acceptable limit, ending unnecessary flushing of the system.
Mobil reports the upgrade to the cooling tower control system is saving them 70 megalitres of water a year, representing about 3% of total water use at the refinery.
Trade waste discharges have reduced by a similar volume.
