Balancing a Community’s Wastewater Aspirations with Affordability - The Gisborne Experience

On 22 March 2011, Gisborne District Council officially opened the Banks St Wastewater Treatment Plant. The $40M project, which provided a new milliscreening facility, biological trickling filter (BTF), industrial separation and screening, prior to discharge to the existing long sea outfall, was a major step forward in addressing many of the community’s long term wastewater aspirations.

However, it was not considered to be a final solution. Council was required by consent to further investigate the feasibility of alternative use and disposal (AUD) options, with the ultimate goal of removing treated domestic discharges from the outfall.

This paper is a follow on to the 2009 Water NZ paper “Gisborne Wastewater Scheme: Successfully Re-Defining a Community Project”. It provides a history of the Gisborne wastewater story from the commissioning of the long-sea outfall in 1965 through to the conclusion of the 2016 Alternative Treatment and Disposal study, which sets the scene for further options assessments. It describes the issues and challenges of scaling the alternative natural treatment pilot trial undertaken by GDC and NIWA to a full scale design and development of cost estimates. It also describes the development of the consented default Stage 2 design and the value-engineering work undertaken to progress towards a solution which meets the environmental, social, cultural aspirations of the community whilst balancing the economic impacts. This project is ongoing and is expected to conclude with a refined set of five options being ready for community consultation in August 2017.