Boosting Crop Production by Spreading Effluent
Tararua district farmer Jamie Harris milks around 400 cows using a split calving system on his farm, Crossdale Dairies.
At the milking shed, the Flush Valve offers quick and easy wash-down using high volumes of fresh water or recycled effluent (‘green water’). This has a 5.5m clearing width and the liquid is delivered in a horizontal plane with little or no splashing vertically.
The heart of the system is a valve actuated via a robust airbag system for opening or closing; it requires only 40psi to achieve a head of 8m.
It’s reckoned easy to install and maintain via large access panels.
The Agri-Pump, a dual-purpose unit that agitates and pumps, can handle effluents with high fibre or solids content to supply a constant flow of well agitated material.
Using a rugged propeller knife and impellor blade system, the belt-driven unit has a pump whose revs are easily adjustable, and a rotating nozzle (optional) deals with crusts or stagnant liquid.
The unit mounts on the side of the reception pit and is supported at the base; this siting allows easy maintenance. Its 3-way gearbox drives a propeller and an impellor, to agitate and pump from a common drive shaft. The cast iron impellor carries four curved blades to pump through a 100mm outlet pipe.
In many installations the pump flow might be directed to a GEA Slope Screen that separates the liquid and solid portions of effluent, reducing wear and blockages in pumps, effluent lines and irrigator nozzles.
The liquid portion can be held in a storage tank and re-directed for wash-down, saving clean water, while the solid content can be used as a fertiliser or soil conditioner.
In operation, the Slope Screen is mounted on a platform above a solids bunker, with a flow of untreated effluent directed to the top of the screen via a regulator valve. As the effluent moves down the screen the liquid passes through to a holding tank while the solids are collected in a loading bunker.
