Project two - Re-consenting, then upgrades to the Porangahau and Te Paerahi Wastewater Systems

Background

The Porangahau and Te Paerahi Wastewater Treatment Plants consents expire in 2021. A condition of these consents were that Council work on removing the current Te Paerahi Treatment Plant and discharge from its current site, and to work toward ceasing river discharge into the Porangahau River. When the current Council begun to prepare for replacing these consents in 2018, we recommenced discussions with the community on how this should happen.  

Existing Wastewater Network

Option one

• Minor treatment improvements at both current Wastewater Treatment Plants
• Convey wastewater (build pipeline) from Te Paerahi to the new land site
• Construct a new land discharge site
• Continue to discharge Porangahau to river but at slightly better treatment

Benefits:

• Improved treatment levels
• Land discharge site established
• Reduced discharge to sand dunes
• New consent
• Able to grow when funding available
• Meets one part of cultural aspirations

Result:

• 1 new discharge to land site

Cost (approximate):

• 7.3m

Option two

• Construct a new centralised land discharge site.
• Convey wastewater from Te Paerahi and from Porangahau to the new land discharge site.
• Continue to treat at Porangahau, but convey to the new landsite for discharge but allow for Porangahau river discharge in high flows.
• Continue to treat at Te Paerahi
• Minor improvements to both treatment plants

Benefits:

• Improved treatment levels
• New common land discharge established
• Reduced discharge to sand dunes
• Reduced discharge to river
• New consent
• Able to grow when funding available
• Meets one part of cultural aspirations

Result:

• 1 new discharge to land for both towns

Cost (approximate):

• 9.7m

Option three

• Convey Te Paerahi’s and Porangahau’s wastewater to common land site for disposal
• Construct a new land discharge site.
• Build storage to allow all wastewater to a land-based site
• Minor improvements at both sites

Benefits:

• Improved treatment levels
• New common land discharge established
• Cease discharge to dunes and to river
• New consent
• Able to grow when funding available
• Further meets cultural and environmental aspirations

 Result:

• 1 new discharge to land
• Storage

Cost (approximate):

• 17.6m

Approximate Project Two Cost:

The costs go through a refining process as the design progresses. We are currently at a very early pre-concept design phase, and expect the costs to be in the vicinity of $10m.

How might this project be staged?

The way we stage this work will impact the immediate effect on Central Hawke’s Bay’s rates.

• All at once within 2 – 3 years
• Staged within 5 years
• Staged within 10 years