Effluent Management System
Effluent Management System
Effluent Management System
Effluent Management System
Effluent Management System

Prosump and Effluent Management System

Fidel Hardegger, Taranaki Dairy Farmer

The Situation

Fidel is a second generation dairy farmer on a block situated in rugged coastal Taranaki. The farm runs a relatively high stocking rate, and the herd is fed a lot of palm kernel on a small feed pad in front of the main yards. The farm had no effluent storage whatsoever, effluent was transferred from a small sump at the bottom of the feed yards to a catchment sump beside the main yards where it was pumped to the travelling irrigator with a new DODA 15Hp pump.

Taranaki Regional Council (TRC) indicated to Fidel that without adequate storage, he was not able to comply with the terms of his consent to irrigate effluent to land, and he needed to put storage in place ASAP.

The site presented a number of challenges, including

  • Large volume of palm kernel waste in the effluent, which was very hard on the pump and irrigator nozzles
  • Minimal fall available in the site for gravity feed to storage
  • Impermeable iron sand layer 500mm below ground which caused significant drainage issues on the property
  • A peat layer approx. 1500mm underground which looked to be a forest covered in ash from a volcanic eruption of nearby Mt Taranaki
  • Sand from approx. 2000mm underground which had a LOT of water running through it, causing it to collapse if excavated

The Implication

Fidel initially approached Presco as he was impressed with the Prosump recently installed at a neighbouring property, and how Presco had helped that client through the minefield of achieving compliance at a time when there was significant change in accepted practice in effluent management nationwide, and deferred irrigation was a relatively new concept in Taranaki. Presco assisted Fidel with a lot of research on construction options and TRC storage requirements. Presco produced a report from the Massey University developed ‘Dairy Effluent Storage Calculator’ which TRC accepted for the renewed resource consent for the property. We quickly determined that the available depth for construction didn’t allow enough room for gravity feed to the effluent storage so a transfer sump would be required. Due to the unsuitable soil conditions, and the shallow depth available for construction, a suitably sized lined pond would need to be built mostly above ground, and have a very large footprint in prime pasture next to the milking platform.

 

The Solution

Fidel’s preference was for a concrete storage solution, and despite things looking bleak for a bit we were able to work with our engineers to come up with a very satisfactory solution.

The Prosump has 3 mtr wall panels and 1 mtr dish depth in the floor, its built 50/50 in/above ground on a metal pad on top of the sand.

All effluent now runs through separate storm water diversions for the feed pad and main yards, before running through a large custom built sand trap which separates the bulk of the palm kernel solids from the effluent stream. The sand trap overflows into a 22,500Ltr pump chamber, where an energy efficient submersible pump and stirrer transfer all effluent to the Prosump, ensuring no solids are left behind.

At our recommendation, Fidel installed a new shore mounted horizontal stirrer on the apron of the Prosump. Thanks to the efficiency of the Prosump shape, the stirrer only needs to run for 30 mins to get all the palm kernel and effluent solids into suspension for pumping to pasture with Fidel’s existing pump, which was installed on a new pontoon. All equipment mounts, cable and upstands for the irrigator mainline are tidily set into the concrete apron.

Changing from a zero storage effluent system to deferred irrigation with storage capacity to spare presented a huge change to the farm operating system. Despite initial misgivings about this change, and the investment required to upgrade his system, Fidel has quickly adapted and now loves the flexibility the system gives him to focus on other tasks through the winter and spring.

The effluent system has a significant impact on the visual appearance of the property, and would certainly reflect in the value of the farm. The system is above and beyond what TRC required, and will continue to operate for many years without any need for further upgrades or any significant maintenance.

0800 773 726
06 278 0712
15 Scott Street
PO Box 530, Hawera, 4610
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