Why forest treatment is the preferred option

It has been recognised since the late 1990's that a new wastewater treatment plant would be required for the Kerikeri community at some time in the future. The extraordinary growth in the last decade has made the need for a new plant urgent.

Alternative sites have been investigated within the Kerikeri region over the last few years to assess suitability for a new wastewater treatment plant.

A suitable site needs to meet the following criteria:-

Availability of land at a reasonable price
Suitable buffer zones from not only existing development but also developments planned for the future
Availability of a route for the disposal of the effluent
 

Four main options were initially investigated:-

Existing Wastewater Treatment Plant site near the Cobham/Inlet Roads junction.
End of Bluegum Road within the Waitangi Forest
Land near the Okura Estuary
Land north of Kapiro Road
 

This initial investigation concluded that the best of the four options was the location within the Waitangi Forest. All other locations were all deemed to be too close to human habitation, did not offer suitable means of effluent disposal and were on land that was of high development value or of high agricultural or horticultural yield.

The next move was to investigate a site within the Waitangi Forest which offered the best solution for Kerikeri. A further four sites within the forest were considered including the existing treatment plant serving Paihia, Waitangi, Haruru Falls and Opua.

Extensive negotiations were entered into with the Crown as Waitangi Forest owners to secure a suitable site for a stand-alone Kerikeri wastewater treatment plant. After nearly three years of negotiation it is clear that land within the forest for a stand-alone plant is never going to be a practical option and negotiations have ended.

The decision was made to seek to develop the existing Paihia wastewater treatment plant in the forest to take the combined flows from Paihia, Haruru Falls, Opua, Kerikeri and Waipapa.

Advantages are the site is far removed from present and future planned human habitation, there is sufficient land to expand the existing plant and there is a tried and proven disposal pathway for treated effluent extending through nearly seven kilometers of wetland before reaching the tidal estuary.
 

Disposal of the effluent to land has been considered. To have met the Northland Regional Council's policy criteria for land discharges at a location outside the forest would have meant the purchase of a minimum of 700 hectares, and potentially up to 1225 hectares of land. At an estimated $20,000 per hectare the potential cost of land purchases was a staggering $14 million –before the first sod could be turned in the construction process.