The Green Island landfill is due to close before the end of the decade and the council is now developing what it calls a "resource recovery park precinct" at the site.
The resource recovery park precinct will be used in concert with the council’s new kerbside collection system scheduled to begin in July.
Construction of an organics receivals building is under way — and a council spokesman said the single level building was on track for a July 1 opening, in time to accept organic waste picked up in the new kerbside collection system.
Additionally, detailed design work was under way for several other facilities: an organics processing facility for food and garden waste, a material recovery facility for mixed recyclables, a construction and demolition recovery facility, and a bulk waste transfer station for general waste, the spokesman said.
Waste from the bulk waste transfer station would be transferred to the landfill tip face at Green Island for now.
Upon Green Island landfill’s closure the waste would be transported to the planned Smooth Hill landfill, near Brighton, or another waste disposal facility.
Consent application documents said the council had been discussing its Waste Futures Programme with iwi consultancy Aukaha and Te Rūnaka o Ōtākou since 2019.
A hui and site visit was held, with representatives from both, in April 2022.
"Acknowledging that the site has been used as a landfill since the 1950s, a number of areas of interest were highlighted that have been incorporated into the design of the [resource recovery park precinct] as the project progresses," the application said.
Priorities included the need to protect and restore Kaikorai Stream and Estuary, they said.
Incorporating mana whenua design principles or narratives in buildings and supporting infrastructure was deemed important, as was the use of "nature-based solutions", native planting and maintaining views to Saddle Hill (Pukemakamaka).
The Green Island site had been used for waste disposal since 1954, the application said.
The site of the planned resource recovery park precinct had been capped after it was last used in the late 1970s, before Green Island became the city’s main landfill in 1981.
The waste beneath the cap where the resource recovery park precinct was planned was estimated to be 6m to 8m deep.
Before the landfill was there the land was a tidal estuary, the application said.
Waste was originally disposed of "directly on to the estuarine muds and up against the southern Kaikorai Estuary edge".
Still, today Kaikorai Lagoon was listed as an area of significant biodiversity value in the council’s district plan, the application said.
It was described as having "regional significance", and containing mudflat, saltmarsh, reed swamp and succulent herb swamp.
It was also listed as a wāhi tūpuna (a place of cultural significance).
The Otago Regional Council additionally listed the lagoon as a regionally significant wetland in its water plan, the application said.
Consultants Boffa Miskell concluded the redevelopment would not adversely affect the ecological values of the lagoon as existing stormwater and leachate systems were sufficient in terms of capacity and treatment.
The resource recovery park precinct would be run by Enviro NZ on behalf of the council, the application said.
A range of present features at the site would remain.
These included the kiosk and weighbridge, the existing Rummage store, the domestic waste drop-off and transfer station (until it was replaced by the new bulk waste transfer station), and recycling and garden waste drop-off areas, it said.
