Contact Us

Melbourne Water

Melbourne's water
storages are currently

34.7%

Eastern Treatment Plant - Planned Upgrade

Aerial view of the Eastern Treatment Plant

In October 2006, the Victorian Government announced plans to upgrade the Eastern Treatment Plant to improve the quality of the treated effluent it produces.

The upgrade remains on schedule for completion by end-2012.

The main benefits of the upgrade are:

  • Reduced impact on marine environment at Boags Rocks, where treated water is discharged
  • More options to use treated water for non-drinking purposes (recycled water)
On-site trials plant where different treatment technologies were trialled.
Finding the right treatment process

A year of technology trials (completed first half of 2009) has helped find the best treatment process for upgrading the plant. Here's what the trials involved:

  • Creating a mini-treatment facility on-site for testing technologies side-by-side
  • Establishing an on-site laboratory to analyse water samples from the various treatment processes on the spot and understand the performance of each treatment process under different conditions
  • Working with world-class private sector partners on more than 10 different treatment options
  • Keeping the community informed about our progress

The trials have been very successful. They found that an advanced tertiary treatment process – Ozone and Biological Media Filtration coupled with ultraviolet and chlorine disinfection – would greatly improve the quality of treated effluent from the plant and address impacts in the vicinity of the discharge point.

A standard tertiary upgrade would:

  • eliminate litter
  • reduce turbidity and suspended solids, oil and grease
  • further improve disinfection

On top of this, our preferred advanced treatment process would also:

  • reduce colour, odour, foaming potential and ammonia in treated water discharged from the plant
  • increase the potential for more recycled water use over time and hence further reduce the volume of treated water discharged to the marine environment

More information:

Tertiary Treatment Trials - processes and sequences

(Click to enlarge)

Underwater outfall

Treated effluent from the Eastern Treatment Plant is discharged at Boags Rocks, near Gunnamatta.

The original requirement for upgrading the Eastern Treatment Plant included an extension of the underwater outfall to improve the marine environment – plus upgrading the sewage treatment process itself.

The technology trials showed the advanced tertiary treatment process can significantly improve the marine environment without having to extend the outfall.

Upgrade cost

Now that the final treatment process has been identified, cost estimates for the upgrade have been updated to $380 million. (This is expressed in nominal, inflation-adjusted terms.)

We estimate $400 million could be saved by not extending the existing underwater outfall.

EPA Approval for Eastern Treatment Plant Upgrade

EPA approval is required under the Environment Protection Act (1970) before Melbourne Water can make any significant change to the Eastern Treatment Plant.

In January 2010 EPA Victoria approved Melbourne Water’s application to upgrade the Eastern Treatment Plant. This followed a rigorous scientific assessment of the submission and a 21-day public consultation period that gave stakeholders and the general public the opportunity to comment on the planned upgrade.

Further information on the Eastern Treatment Plant Works Approval includes the following:

Next steps

Now that regulatory approval has been received from EPA Victoria, the upgrade is subject to a final round of Government approvals before it can proceed.

Pending this approval, construction is expected to begin in mid-2010.

Protecting the marine environment

The main reason for upgrading the Eastern Treatment Plant is to meet EPA Victoria's licence objectives for what is discharged into the ocean, near Gunnamatta Beach. The upgrade will mean an improvement in the quality of the treated water that is discharged . The upgrade will eliminate litter and oil and grease, significantly reduce suspended solids, colour, odour and foaming potential, and further reduce ammonia in the treated water as well as providing very high levels of disinfection. As a result the receiving marine environment will be improved and health risks to recreational users of the marine environment will be further reduced.

Improved water recycling

Improving the treatment process means treated water from the plant will be suitable for a broader range of non-drinking purposes, including those that require high quality recycled water (commonly referred to as 'Class A').

The upgrade to Eastern Treatment Plant means up to 100 billion litres a year could ultimately be used across a wider range of non-drinking purposes.

Finding uses for recycled water

Recycled water needs its own set of pipes for delivery to customers (sometimes called 'third pipe'). It takes time to build this, so it will also take time to find productive uses for all of the high quality recycled water available from the Eastern Treatment Plant.

Two major re-use options for the recycled water were investigated by the Victorian Government but these were found to be too expensive.

South East Water customers will use about 7 billion litres of extra recycled water a year when the upgrade is finished at the end of 2012. Potential projects to recycle up to 40 billion litres a year in total from ETP over time are being investigated.

See also: