Selwyn Water

C2526-002 Pines Wastewater Treatment Plant- New Inlet Works

Selwyn District continues to see rapid growth in residential and commercial development, particularly in the urban centres of Rolleston, Lincoln, and Prebbleton. These communities are serviced by the Selwyn Sewerage Scheme (SSS), which comprises pumped conveyance to the Pines Wastewater Treatment Plant (WWTP) for centralised treatment and disposal. The Pines WWTP is located south-west of Rolleston and operates as a Biological Nutrient Removal (BNR) plant, with treated effluent discharged to the surrounding land. The current plant is designed to treat in the order of 60,000 Population Equivalent (PE) flows and loads, a capacity limit that is fast approaching. To cater for this growth, the SSS and Pines WWTP are scheduled to undergo significant staged expansion over the next 10-year period, with the ultimate aim of increasing treatment and disposal capacity to 180,000 PE.
As part of the planned expansion of the Pines WWTP, SWL has identified the replacement of the existing inlet works as an early and critical component of the overall upgrade programme, forming Stage 1 of the planned works. New inlet works are required to increase hydraulic and treatment capacity, and to provide a reliable and maintainable foundation for the broader plant expansion works that will follow.
The works under this Contract are to be delivered under a Design and Build (D&B) delivery model, whereby the Contractor shall be responsible for the design, supply, construction, installation, and commissioning of the new inlet works and all associated works at the Pines WWTP. The Contract Works include, but are not limited to, the inlet works structure, site layout and grading, pipelines and services, foul water packaged pump station, roading and drainage, buildings and other civil structures, and electrical and controls systems, as further detailed in the relevant sections of this document. The inlet works structure is intended to receive and screen incoming wastewater flows, providing the primary treatment interface for the expanded plant capacity.