Gracemere WWTP Inlet Works Upgrade

Waternish was engaged to design, fabricate, install and commission an elevated inlet works for a design flow rate of 230 L/s. We designed the channels, piping, platforms and support structure.

Client
Rockhampton Regional Council
Value
$1.4million
Project Completion
June 2016

The Gracemere WWTP was constructed in 1984 with a capacity of 4 ML/d and is a plant operated by the Rockhampton Regional Council, servicing the growing satellite city of Rockhampton in Central Queensland.

Previously, the plant had an inlet works with a manually raked bar screen which discharged into an aeration ditch, followed by clarification with disposal via land irrigation.

Increased inflows and a changing wastewater characteristic resulted in the existing bar screen posing a safety issue for the operators cleaning it, and a process issue as it was prone to overtopping and sending unscreened wastewater into the aeration tank.

Waternish was engaged to design, fabricate, install and commission an elevated inlet works for a design flow rate of 230 L/s.
Waternish designed the channels, piping, platforms and support structure to accommodate only mechanical equipment from suppliers.

Included in the design was a duty standby screen arrangement, overflow chamber for flows exceeding 230 L/s, grit vortex removal system, grit extraction pump, grit washer, and service water system. Waternish prepared a control philosophy from which the plant’s automated control and monitoring system were developed.

In addition to the installation of the inlet works, a number of pipework tie-ins were required including outlet, bypass, and three inlet mains in diameters ranging from 100 to 350 mm.

There was little As-Constructed documentation available from numerous past plant upgrades, so significant potholing was required with a number of contingencies put in place during the tie-in to ensure that unexpected conditions could be dealt with. Waternish was then able to provide detailed, updated drawings to the Council indicating the in-ground pipework.

At the completion of construction, the inlet works were commissioned and brought into service, leading to an overall improvement in the performance of the Gracemere WWTP.