Palmerston North Wastewater Treatment Plant

Palmerston North City Council

Palmerston North, New Zealand

Palmerston North City Council required a review and improvements to the performance of their Anaerobic Digestion Systems at the Palmerston North Wastewater Treatment Plant (WWTP).

Our team’s anecdotal evidence suggested long-term under-performance had been occurring. Our team undertook hydraulic residence time testing on the digesters to reveal that nearly 50% of the reactor volume was poorly mixed and had been for many years despite a number of previous reviews.

Calibre acted as process designers, as well as mechanical and electrical commissioning engineers. First our team undertook hydraulic residence tests and from these recommended a short-term, transitional mixing system, followed by a longer term solution. The short-term solution improved performance sufficiently, allowing a single digester to accept the entire plant’s waste sludge. This allowed the second reactor to be removed and upgraded.

Palmerston North Wastewater Treatment Plant

The modifications made to the system increased the system capacity more than 300%. On our recommendation the council developed the facility into a co-digestion facility for combined source segregated trade sludges and waste, as well as biosolids. As a result the gas production has increased three-fold, resulting in an upgrade payback period of less than three years.

Project highlights

  • Enabled new revenue streams
  • 300% digester capacity increase
  • Green electricity export to grid

Business:

Consulting

Awards:

  • 2015 ACENZ Innovate NZ Awards of Excellence – Silver Award

Contact

Jurgen Thiele

Business Unit Leader – Waste Recovery – Calibre

+64 3 374 6515
Email me

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