Wastewater Treatment Plant Upgrade Project

Ww06Mar19

Project Background

Early in 2014, Council adopted a long term vision of removing all effluent discharges to water other than in exceptional circumstances. The project to develop Daleton Farm then began, underpinning information collection to support the 2017 consent
renewal process.

The Council sought a further short term consent to allow the discharge of treated wastewater onto land (Daleton Farm) using a pivot irrigator. This allowed deficit
irrigation, over an area of approximately 20ha via a “smart” centre pivot irrigator, installed in 2014.

The short term consents allowed the Council to gather data and carry out investigations on the land discharge option. The Council then spent the next three years designing the upgraded treatment and disposal project and preparing resource consent applications. In December 2016 the Council adopted a strategy for the upgrade, which formed the basis of the applications.

Stage 1 (2015 - 2017)

− Continue inflow & infiltration investigations.
− Continue network condition assessment, rehabilitation & replacement.
− More tightly manage trade wastes.
− Implement the 2014 consent for Stage 1 irrigation to land on Daleton Farm.
− Install UV disinfection.
− Operate and monitor the environmental effects of land irrigation
− Prepare application for replacement consents informed by monitoring data (for lodgement April 2017).
− Develop sustainable land use practices on Daleton Farm
− Pilot scale test and design Sequential Batch Reservoirs
− Line the inlet and outlet channels and replant the existing wetlands

Stage 2 (2018 - 2025)

− Construct on-site Sequential Batch Reservoir treatment and storage on Daleton Farm (100,000m3).
− Relocate the existing stream discharge to the lower reach of Mangatārere Stream immediately above the State Highway 2 bridge and close to the confluence with the Waiohine River.
− Install second centre pivot and extend on-site irrigation area.
− Discharge to stream during high stream flows (except in rare events when extreme weather conditions overwhelm on-site storage capacity).
− Further develop amenity wetlands.
− Continue inflow & infiltration investigations including interception and lowering of shallow groundwater.
− Continue network condition assessment, rehabilitation & replacement.
− Continue to tightly manage trade wastes.
− Progressively investigate opportunities for supplementary land for additional storage and irrigation.
− Develop sustainable arrangements that facilitate long term security of tenure over privately owned land available and suitable for irrigation.

Stage 3 (2026 - 2045+)

− Progressively expand supplementary bulk storage capacity for treated wastewater off-site as land becomes available and is affordable (land additional to Daleton Farm).
− Extend irrigation to land additional to Daleton Farm as suitable private and/or Council-owned land becomes available and is affordable.
− Continue irrigating treated wastewater to Daleton Farm.
− Continue high-flow stream discharge until an alternative option was implemented.
− Continue inflow & infiltration investigations.
− Continue network condition assessment, rehabilitation & replacement.
− Continue tightly managing trade wastes.

Budget & Expenditure
Activity Budget Expenditure

Stage 1 Development

• Investigation and design

• Wetlands refurbishment

• Upgrade existing treatment plant

• First pivot irrigator

• 35 year consents

$4,500,180 $2,678,560

Stage 2 Reservoirs and ephemeral stream relocation

• Investigation and design

• Reservoir construction

• Wetland refurbishment

• Ephemeral stream relocation

$5,067,930 $5,503,480

Stage 3 Pumping and pipeworks

• Investigation and design

• Pumps and pipes

• Second irrigator

$2,694,260 $3,874,350
Construction total $12,262,370 $12,056,390

 

The estimated costs to complete (2021-2022) is $400,000. The current draft 10 Year Plan include provision for $106,000. The additional $300,000 will be included in the final 10 Year Plan to be adopted in June. The additional provision will have a negligible impact on borrowing levels and will add $18,000 annually to the rates.

Current position (Total spend) for WWTP as at May 2021

Authority Spend Difference
$15,767,360 $14,262,820 $1,504,540

 

Note: $2.7 million was spent acquiring the land for the WWTP extension and $0.9 million was capitalised for the obtaining of resource consents, this latter task also
included conceptual investigations

Public reports

All public reports are part of Council and committee meeting agendas. All agendas as far back as 2016 can be found here

To save you time looking through all the agendas, we have compiled all the public reports on the wastewater treatment plant upgrade project which you can access below. All reports have been labelled with the corresponding agenda and page number should you wish to look for that specific agenda in full.

  • 2018 public reports, click here
  • 2019 public reports, click here