This Request for Proposal pertains to the construction of the perimeter, internal haul road/cell walls, drainage materials (positioned between biosolid layers), including the supply and placement of materials as outlined in Annex 1 Specifications.

The Puketutu Island rehabilitation site was inaugurated in 2013 and currently receives around 135,000 tonnes of biosolids annually from the Mangere WWTP.

The Puketutu Island Biosolids facility necessitates the construction of "cells" to facilitate biosolids placement. These cell walls also serve as "haul" roads for biosolid placement.

Approximately 135,000 tonnes of biosolids are anticipated from the Mangere WWTP in each of the next two fiscal years, dictating the number of cell walls to be erected.

The cell walls constructed previously amounted to the equivalent of 250,000 tonnes of imported material. This material is delivered to the site, stockpiled, positioned, and compacted according to design specifications. A similar volume of cell walls is projected to be constructed in the financial years 2024/2025 and 2025/2026.