Grant Coombes | Te Aroha, New Zealand


New Effluent System

440 Cows

Commissioned 2019

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The new effluent management system should keep us going for a long time, it should outlast our milking shed and make sure we’re compliant.

Installing a new effluent management system has reduced labour and taken the guess work out of meeting effluent regulation standards.

“Our new effluent system saves a lot of time not to mention it’s a worry off my mind.” Grant said “I don’t have to spend time grabbing a tractor, putting it on a pump to irrigate effluent anymore, or worry about moving the irrigator around from paddock to paddock”.

Grant is the third generation of his family to farm the 150-hectare property near Te Aroha in the Waikato.

He has 440 cows, split into two herds, which produce about 150,000 of solids, to co-op Fonterra. He has one fulltime worker and a part-time milker.

Grant said it became obvious the old effluent storage pond on the farm was at capacity. “We decided we needed a totally new effluent system. Our old pond was past its used-by date, so we thought we should be proactive, rather than reactive, and get something sorted.”

Knowing the soil composition was key to determining the effluent system which would best suit the property. 

“We’ve got mainly sandy loam soils here and a bit of peat which is a bit heavier, so wet springs can be more of a challenge,” he said.

Grant reached out to the team at Hi-Tech Environmental Solutions in 2018, which became fully integrated with Waikato Milking Systems in 2019. It now operates as the Effluent and Environmental Service under the company.

Grant said he had always dealt with Hi-Tech and even still uses a mobile PTO pump he purchased from the company, that he estimates to be around 20 years old.

He also has an older model Cobra Travelling Raingun which he still uses to irrigate.

“I knew the Effluent and Environmental team would give me the best advice and design a really good system for the farm.” 

The new system was designed to process rain water coming off the dairy shed roof as well as the water and effluent from the dairy parlour during milking time. 

The water and effluent are gravity fed a short distance from the shed to a Stone Trap, where over time, stones and grit will settle to the bottom. The material can later be scooped up, using a tractor, and moved to a Storage Bunker. The material can be spread from the Storage Bunker, over pasture at a later time.

The filtered water and effluent from the Stone Trap are gravity-fed to an adjacent Sump Tank, where it can be pumped out to irrigate to land, or diverted to a new, larger storage pond, which measures 42m x 42m x 3m.

The new storage pond was constructed about 500m away from the dairy shed and the Sump Tank, to avoid the high-water table in some parts of the farm.

“We wanted a site that had free-draining ground, so we didn’t run into ground water when we put the storage pond in.

“The new storage pond is right next to the main effluent line so it’s easy to pump into it, it’s not a hassle at all.”

Installing the large storage pond took only about 10 days. A fence around the pond was to be constructed, to keep it secure from stock.

The entire project was completed in a few months and Grant said he was happy with the installation.

“The new effluent management system should keep us going for a long time, it should outlast our milking shed and make sure we’re compliant.”


Parlor Components

  • Long Shaft Sump Pump (25hp)
  • Flometer
  • Storage Sump
  • Stone Trap
  • Solids Bunker
  • Controller
  • Effluent Storage Pond