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Upgrading the Eastern Treatment Plant

Aerial view of the Eastern Treatment Plant

Construction is underway on a major $418 million upgrade of the Eastern Treatment Plant.

The plant, which was built in 1975, will be transformed into one of the most sophisticated facilities of its kind in the world.

The upgrade remains on schedule for completion by the end of 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)

Read a media release about the upgrade.

        

           

        

Eastern Tertiary Alliance
Our construction partners

We’ve teamed up with Baulderstone, UGL Infrastructure, Black & Veatch and KBR to form the Eastern Tertiary Alliance to complete the detailed design and build the new components.

The alliance will be responsible for building seven new structures over approximately six hectares of land within the existing Eastern Treatment Plant boundary. The new components include a tertiary supply pump station, ozone injection and ozone production buildings, biological media filters, UV system and two large chlorine contact basins.

What is tertiary treatment?

Sewage at the Eastern Treatment Plant is currently treated to secondary standard in a process that involves screening and sedimentation to remove litter, grit and sludge, followed by biological treatment and disinfection with chlorine. By adding a third, ‘advanced tertiary’ stage we can:

  • eliminate litter
  • reduce turbidity and suspended solids, oil and grease
  • further improve disinfection
  • 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
The process in detail
View diagram of the key stages of the process

The key stages of the advanced tertiary process are illustrated here and include:

Step 1. Effluent from the secondary stage enters the advanced tertiary treatment plant. The new Tertiary Supply Pump Station will lift effluent out of the existing Effluent Holding Basins to begin the tertiary process.

Step 2. The first step is the addition of ozone for disinfection, for the reduction of colour and odour, and to optimise the rest of the treatment process.

Step 3. The biological filters are a key part of the tertiary process. Here, helpful bacteria biodegrade the organic matter and reduce ammonia, oil and grease, foam, litter and solids.

Step 4. More disinfection using ozone. The ozone is generated on-site from oxygen.

Step 5. Next, the effluent is exposed to ultraviolet light for further disinfection.

Step 6. Chlorine is added as the third and final disinfection treatment. Treated water enters two large chlorine contact basins as part of the disinfection process. The basins are also used to feed the treated water to the outfall pump station.

Step 7. Tertiary treated water is transferred to the existing outfall pump station where some is recycled and the remainder is discharged to the ocean under EPA Victoria licence.

The ETP treatment process
View the process in more detail

The road to tertiary treatment

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

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 were 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.

More information:

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

Cost estimates for the upgrade have been updated to $418 million. (This is expressed in nominal, inflation-adjusted terms.)

We estimate $400 million has been 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:

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: