Brackish water can be a huge issue for livestock producers.
That was the problem facing Mt Eba Station co-owner Peter Whittlesea, with the station’s bores ranging from salinity levels of 3500 parts per million up to unusable levels for livestock of 11,000 to 12,000ppm.
But two years on from installing a Puredrop desalination plant, he believes he has found a low-cost solution for the 3370 square kilometre pastoral property, located in the geographical heart of SA, near Glendambo.
At last week’s Ten Minute Tech – Water Management/Technology webinar run by Sheep Connect SA, Mr Whittlesea explained how the Vic-manufactured unit, worth about $8500, was providing drinkable water for the homestead and surrounding buildings.
The unit, run by a 0.5 kilowatt motor, is capable of producing 700 to 800 litres an hour of water, which is fit for drinking.
Since mastering the plant, he is hoping to scale up to provide good quality water for large mobs of sheep, up to 7000 to 10,000 head, in their livestock holding paddocks.
“It is a vast area so some of them have had to walk up to 60 kilometres over about a week into the yards for shearing so they are already under a relative amount of stress,” he said.
“Then we add salty water and it puts them under a bit more stress so the plan is to lessen the salt level as much as we can.
“Once we can upgrade our power we will install a large storage tank and run the pump for longer.”
The desalination plant is fed from two water sources – a bore at the homestead with water quality of about 3500ppm and another with a higher flow rate but at 6500ppm.
A submersible pump brings the water from each bore to the surface where it goes into a 40,000 litre settling tank.
A pressure pump sucks from the top of the tank into a 300 metre line into the desalination plant.
The unit, powered by another 1.1kW motor, pushes the brackish water through four cylindrical tubes and removes the salt via reverse osmosis.
“As soon as the system is pressurised to 30 pounds per square inch to 40psi it kicks in and one micron filters keep the iron and sand out,” he said.
Mr Whittlesea says the most expensive parts of the desalination unit are the cylinders’ membranes, which cost close to $500 each, but in comparison to other systems it is cheap to run.
“I’ve blocked one set up with sand and iron when I was learning in the first six months, but if it is done right they (Puredrop) assure me they should last 10 years,” he said.
In the next few years, Mr Whittlesea plans to attach more Puredrop desalination plants to outlying bores.
“It will open up a considerable amount of country to run stock where we can’t at the moment,” he said.
