Dairy Effluent Management: Right Amount at the Right Time
Good effluent management on a dairy farm combines a well-designed system with proper processes to ensure the right amount of effluent gets applied to pasture at the right time.
A prototype has been running on a dairy farm at Te Poi.
The system enables dairy farmers to comply with all dairy effluent and water consent regulations well into the future, says managing director Terry Hawes.
“We’ve been working on this for some years and now have a system we believe will be fully compliant and need no expensive ponds and irrigation systems. Our checks show that the water is close to New Zealand drinking water standards so it can be irrigated with no permits needed,” says Forsi operations manager Craig Hawes.
Central to the system’s effectiveness is a screen separator of Forsi’s own design.
“We were not happy with the commercial screens available and the results they delivered. Our screens extract more solids and are self-cleaning either automatically or manually.”
The system takes effluent from the cowshed, through separation screens and the containerised processing plant, producing clean, clear, pathogen-free water ideal for yard washing or irrigating to pasture, the company says.
Solids extracted during primary screening are bunkered for later spreading. And the solids extracted during secondary (fine) screening inside the container – referred to as ‘chocolate mousse’ because of its texture – may either be added to the primary-screened solids or further treated separately and kept apart for other uses. It has higher nutrient concentration than the primary-screened material.
In operation, effluent from shed and yard first passes through a sand trap, then through a Forsi-designed primary screen separator outside the container, then through screen separation (Forsi’s own design) inside the customised container, then through final processing – ozone tanks and a UV treatment that renders the water potable quality, Forsi says.
Only one day of work is needed to connect the container to external piping and electricity.
“Processing will consume only 8kW power. Cost benefits are obvious when you compare that with the 20kW and bigger motors to run stirrers and pumping motors, plus the labour needs; then there’s the elimination of land-wasting effluent ponds.”
Dirty in, clear out
Alan Hitchcock's farm at Te Poi, on the Matamata—Tauranga road, is the site of the Forsi Innovations prototype effluent system.
Hitchcock had previously dealt with Forsi Innovations, which also runs a water filtration business.
His farm, 155ha (eff.) of flat land, is about to start its third season in his ownership, wintering 480 cows.
“When we arrived we knew our effluent disposal was marginal and we had to do something about it,” he says.
The flat farm has a high water table and had many paddocks humped and hollowed. Because these drain to a waterway, spreading more liquid effluent was not an option.
The Forsi containerised effluent system was running for a short time before the herd was dried off.
Says Hitchcock, “When you see [dirty] material going in and crystal clear water coming out you are seeing a major breakthrough in treating dairy effluent.”
Tel 021 685 411
