Friday, 18 May 2018 07:55

No s**t Sherlock

Written by  Nigel Malthus
Samples of dairy effluent on show at the launch of the ClearTech system show how suspended solids precipitate out under the influence of a special coagulant. Samples of dairy effluent on show at the launch of the ClearTech system show how suspended solids precipitate out under the influence of a special coagulant.

If every farm in New Zealand used the new ClearTech system for harvesting clean water from dairy effluent, NZ would save 42 billion litres of freshwater each year.

That’s according to Ravensdown, which recently unveiled the system with its Lincoln University partners in the project. 

ClearTech results from research by soil science professors Keith Cameron and Hong Di, who have identified a coagulant which, when mixed with dairy effluent, causes the solids to precipitate out and leave most of the water clear. The computer-controlled process also kills most bacteria.

Installed between a farm’s dairy shed and effluent pond, it produces water claimed to be of swimmable quality for recycling for yard washing. 

A pilot system was recently shown running at the Lincoln University Dairy Farm. Ravensdown expects to be marketing commercial systems late this year.

Jamie Thompson, Ravendown’s ClearTech project manager, explained that the coagulant chosen is polyferric sulphate: the main constituents are sulphur and iron, two substances  already common in the soil.

Once the solids have precipitated out and the clear water is taken off the top, the concentrated remainder in the effluent pond is good for spraying on pasture.

“It’s about 99% water initially. Once we’ve taken the water off it’s still only 3% solids -- 97% water,” said Thompson.

“Irrigation equipment can pump it easily. In technical terms it might be called a slurry but it’s nowhere near a slurry, it’s still very liquid.”

They expected no ill-effects from the extra iron and sulphur ending up on the pasture.

“That’s minor: environmental scientists have looked at it and it’s minimal. In fact a lot of the iron and sulphur break down while it’s still in the effluent pond,” said Thompson.

Ravensdown chief executive Greg Campbell told attendees at the ClearTech launch that the co-operative’s catchcry is ‘Smarter farming for a better New Zealand’.

That requires innovation such as ClearTech, and working... to find new ways to reduce environmental impacts while enabling farmers to create quality food for more people and animals -- using less land. 

“From our perspective, if that means selling less fertiliser... so be it.”

Ravensdown chairman John Henderson said the co-op is not just a fertiliser company; its environmental consultancy arm is now the largest in NZ.

“We are devoting a lot of our energy to helping our shareholders and farmers in NZ to farm more smartly for the benefit of NZ as a whole.”

The company says it spends at least $2 million a year on ClearTech and similar projects. 

More like this

Lynnette Hudson Named 2026 NZ Winegrowers Fellow

Lynnette Hudson's 30-year obsession with Pinot Noir was sparked working vintage in Burgundy, seeing how subtle changes in terroir were expressed in the glass. It was, she says, "an elightening moment in every way".

Featured

Southland Farmers Face Wet Weather Toll, Support Available

Farmers across parts of Southland and South Otago are continuing to deal with difficult conditions after a prolonged run of wet weather, with pressure building around feed supply, stock management, pasture damage, farm infrastructure and everyday workloads.

How Wearable Tech Powers This 1,850-Cow Dairy Farm

For Canterbury dairy farmers Sian Meijer and Rick Wobben, wearable technology has become one of their most valuable on-farm tools - helping manage 1850 cows across an expansive, high-performing dairy operation while improving efficiency, mating outcomes and day-to-day decision making.

New Dairy Welfare Code Released, Takes Effect 2027

The first major update to the Dairy Cattle Code of Welfare in more than a decade has been released, marking what DairyNZ describes as an important step in ensuring animal welfare standards continue to evolve alongside scientific evidence and on-farm realities.

National

Machinery & Products

» Latest Print Issues Online

The Hound

'LinkedIn Greens'

OPINION: The same mainstream media muppets that brought you Jacindamania in 2017 have been flat out pimping for the Opportunities…

UK Warning

OPINION: Your old mate reckons the atrocious way farmers in the UK are treated by their lords and masters in…

» Connect with Rural News

» eNewsletter

Subscribe to our weekly newsletter