Davieth Verheij from AgFirst Engineering Waikato Ltd designed and installed the effluent system at Wairakei Estate for Landcorp Bounty – the 14th project the company has accomplished for Landcorp over the last four years. The effluent flows through an AgFirst-designed vortex sandtrap and solids storage system prior to arriving at the 4700m3 liquid effluent storage pond. The pond is lined with HDPE by Viking Containment, complete with geotextile underlay, gas ventilation and leak detection system. The pond is agitated by two 4 kW submersible pond stirring system generating a massive 4,000,000L per hour flow rate. The effluent irrigation area on this farm was very challenging. The effluent block is 120ha with the ability to extend up to 324ha. The height variation is 90m through the block and this, combined with the effluent volume from up to 2200 cows, meant a high-capacity, high pressure pump and pipeline system was necessary. “We had a Mono pump purpose-built for the duty in the UK. The pump is the largest known in the New Zealand effluent market with flows up to 40,000L/hr and pressure up to 14 bar (206 PSI),” says Davieth. Landcorp’s irrigator of choice is the Weta Irrigator developed by Davieth from AgFirst Engineering. Landcorp now has nine Weta Irrigators operating on its farms. The revolutionary Weta Irrigator turbine is driven by the effluent flow and hydraulic drive system. It’s the first travelling irrigator in the world to maintain its selected travel speed no matter where it is operating on the farm. The Weta Irrigator offers the least pressure loss, the lowest application intensity and is very low maintenance. It ticks all the boxes for Landcorp. Davieth is impressed that the pond is always empty. Jamie and the team at Landcorp Bounty really know how to manage their new system!

Article first published in the September Issue of Coast and Country.