Australia’s Largest Municipal Ozone Plant Supplied with Four WEDECO Systems

A long-planned upgrade at Melbourne Water’s Eastern Treatment Plant includes a new WEDECO ozone system from ITT Corporation with installation beginning in November 2010.

At average and peak flows of around 380,000 and 700,000 cubic meters per day of treated water production, the A$380 million (€270.1 million) upgrade to advanced tertiary treatment at Melbourne Water’s Eastern Treatment Plant (ETP) will make it among the largest of its kind in the world.

After an extensive pilot testing program begun in 2008 to narrow down the treatment options, the new treatment regimen incorporates ozone treatment, biological media filtration (BMF), and ultraviolet and chlorine disinfection. ITT is providing the ozone technology consisting of four WEDECO PDO 7500 ozone systems with a peak design production capacity of 490 kg/h ozone in total. The generators are fed by oxygen produced onsite from ambient air. ITT’s scope of supply further includes the oxygen generation system, ozone injectors, a variety of monitors, analyzers and other instrumentation, and residual ozone destructors. A participant in the trial program, ITT was awarded the A$16 million (€11.6 million) oxygen/ozone contracts in July. The ETP, which treats about 40% of Melbourne’s sewage or around 330 MLD (with wet weather flows up to 1,750 MLD), also incorporates Flygt pumps from ITT.

The plant is being built by the Eastern Tertiary Alliance, which includes owner Melbourne Water, construction partners Baulderstone and UGL Infrastructure. and engineering consultants Black & Veatch and KBR. The pilot testing identified the preferred treatment train comprising ozone, BMF, ozone, UV and chlorine, requiring two ozone injection points. The upgraded plant is expected to be operational by the end of 2012, and construction of the oxygen and ozone system infrastructure has already commenced. Other ozone equipment is under manufacture now in Germany, with installation of the main ozone systems anticipated to begin in mid-2011.

ITT sales engineer Florian Axt noted the ozone project holds the double distinction of being the biggest in wastewater and biggest in Australia for the WEDECO brand. “The ozone system also is among the largest capacity ozone systems worldwide” he added.

Currently treated to "Class C" recycled water quality, some of the ETP treated effluent is recycled with the remainder discharged to the ocean via a near-shore outfall at Boags Rocks on the Southern Mornington Peninsula. The upgrade is primarily driven by an objective to improve the quality of treated wastewater discharged into the marine environment. The additional benefit of the significant improvement in treated water quality will be the production of high quality recycled water which can be used for a broader range of non-drinking applications than the current recycled water quality.

"This effluent is going to the sea in a location close to popular swimming and surfing beaches," said Louis Wiart, national industry manager for ITT’s Water and Wastewater business in Australia. "Melbourne Water has been monitoring the receiving marine environment for many years and identified a need to reduce the impacts of the discharge on the environment in line with community expectations around environmental performance. Rather than extend the existing nearshore outfall a further 2-km offshore, Melbourne Water decided to go for better treatment and improved treated water quality to address the impacts. Obtaining a very good quality effluent in the future allows it to recycle this effluent for a broad range of applications." Wiart added that pretreatment by ozone oxidation allows the UV systems to be two to four times smaller than otherwise required and reduces chlorination needs as well.

Dr. Tim Puehmeier, ITT product and application manager for ozone, said the ETP upgrade project breaks ground that’s expected to lead to additional work in wastewater for the entire Asia Pacific region. "It’s a great project for us. It’s a nice success story being from a pilot to a final project – that also happens to be our biggest Australian job. That’s just fabulous," he said.