A system used to separate gold from gravel has been adapted to extract solids from dairy effluent by Rainer Irrigation Ltd of Ashburton.
Rainer Irrigation manager Gavin Briggs says effluent solids might not be as valuable as gold, but farmers can achieve significant financial savings by extracting it from water with the company’s Effluent Vibra Screen.
“Taking out the solids to be composted or spread on pasture leaves separated liquids to be used for washdown of yards or in existing irrigation systems, with less risk of blockages.”
The Rainer Effluent Vibra Screen has been three years in development, including two years of on-farm testing. “We wanted to be sure of its efficiency and reliability before going out to market,” says Gavin.
“We now have four up and running with another three going in for the coming season; and one of these is a second order for a client for his second farm.”
Rainer Irrigation manager Gavin Briggs with the Rainer Effluent Vibra Screen at the Fieldays.
The system was on show at the Fieldays where ‘artificial effluent’ was fed continuously over the screen to demonstrate how it works.
“The system can be used to separate solids from liquids in dairy farm and pig farm effluent, from truck wash wastewater and more.”
The separation process has minimal moving parts which provides reliability, low maintenance and low running costs, and the system can be retrofitted to an existing effluent system.
In the first stage of the process, a stirrer mixes raw effluent in a sump or saucer and a heavy-duty pump delivers it to the Vibra Screen, which as its name implies, vibrates, allowing the liquid to pass through the screen while solids are collected and dehydrate as they fall off the screen to a drainage pad.
The end result are two nutrient-rich products, liquid for irrigation, and solids – which Gavin says can be spread on cropping paddocks or become even more valuable for pasture if left to compost.