Work is underway on the installation of a new outfall pipe at Tasmania’s Risdon Vale Sewage Treatment Plant, to replace the existing outfall which has been damaged and is disintegrating.
Installed many years ago, the old outfall pipe will be replaced with new longer lasting polyethylene and will extend 30m offshore into the Derwent River.
TasWater Project Manager, Peter Janisch, said the pipe has been laid in place by an excavator which built its own rock causeway into the water.
“The outfall is secured on the river bed with concrete anchors attached to the pipe and when in place, the excavator removes its temporary work platform, restoring the contours of the shoreline,” Mr Janisch said.
“The new outfall pipe will provide better dispersal of effluent into the river and is expected to improve the quality of the water in the area.”
The key to this is to limit the level of nutrients in the effluent discharge, especially nitrogen which can contribute to the development of algal blooms.
TasWater’s Risdon Vale Sewage Treatment Plant operates under a license from the Environment Protection Authority (EPA) which sets limits for effluent quality.
Ongoing monitoring indicates it consistently complies with the requirements of the EPA’s permit.
“TasWater is working closely with Shaw Contracting to ensure the project is finished on time, meets expectations and minimises inconvenience to people in the area,” Mr Janisch said.
Due for completion by the end of this month, the project is part of TasWater’s commitment to upgrade sewage services in an effort to provide an affordable and sustainable sewerage network and minimise the impact on the environment.