"Clean, Green Effluent Winner"

NZ Dairy Exporter Magazine – 1st of August 2009

An effluent system which has a large positive impact on the environment without costing farmers more money won the Fieldays special 2009 category environmental award.

The Clean Green Effluent System was designed by Southlander Lindsay Lewis. It’s a low application, fully-automated environmental effluent system which distributes effluent evenly over a paddock, reducing the environmental impact.

Direct injection

Lewis said the modulated system can be adapted to any effluent system in stages to reduce initial costs. It is being installed in conjunction with direct injection into a centre pivot. Due to the reduced water usage, daily effluent being distributed to the fields is greatly reduced, meaning the dilution rate at the centre pivot can be as low as 0.5 percent.

“The extra-low application rate ensures a greater percentage of effluent stays in the plant root base,” he said.

“Tests carried out on the system by AgResearch, Mosgiel, showed a huge reduction in all the nasties.”

The AgResearch tests showed filtration of potential effluent contaminants when the effluent was applied to a mole pipe-drained site using a low 0.6mm/day approach.

Compared with a single application of 9mm/day of effluent, loads in mole-pipe drainage induced by daily application were reduced by 75 percent for dissolved reactive phosphorus (P). The figure was 92 percent for total P, 94 percent for ammonium-nitrogen (N), 75 percent for total solids and 99 percent for E. coli.

AgResearch’s Ross Monaghan said the test results clearly showed the difference between the system’s very low application rate and that of a standard system. It was a particularly good approach to applying effluent to heavy, mole-pipe drained soils or soils on sloping terrain.

For more information, phone 0800 400 365.