On a road trip from Darwin to Katherine, you will probably come across Adelaide River, a town named for the nearby water source. This historic town, a much-needed Stuart Highway rest point, is now at the forefront of engineering innovation. Its Water Treatment Plant (WTP) is Australia’s first biological water filtration plant, and was officially opened in December 2015. It has already delivered a significant improvement in water quality performance.
Engineers Australia Northern General Manager Mark Monaghan asked Eric Vanweydeveld MIEAust CPEng NER, Senior Project Manager at Power and Water Corporation (PWC), for his insights on the project.
Tell us more about your latest project.
The Adelaide River Water Treatment Plant improves the quality of drinking water supplied to the town’s residents by iron and manganese biological removal through a two stage filtration process. The $6 million plant is a joint venture between Goodline, Suez Environment and Power and Water.
How does the filtration work?
The first filtration stage, preceded by initial aeration, involves biological iron removal. The second filtration stage, which is preceded by aeration and pH adjustment, removes biological manganese.
The biological iron and manganese removal process was discovered and developed by Suez in the 1970s. It’s undertaken by indigenous iron bacteria (Stalked and Filamentous bacteria), which is naturally present in the groundwater. The bacteria lives inside both filters and transforms the dissolved iron and manganese into particles that are removed by rapid sand filtration.
Is it safe to drink the bacteria?
The iron bacteria do not cause health problems. Chlorine is still dosed at the outlet of the plant to disinfect and remove any pathogens that could develop in the distribution network.
We undertook additional upgrade works, changing the existing process of the water supply system to incorporate a multiple-barrier approach. This maximises the efficacy of the water disinfection and optimises the chlorine contact time for critical control and monitoring. We also cleaned the entire downstream township reticulation system using an innovative ‘ice-pigging’ technique.
What was it like to work on this project?
It was technically quite complex so we faced a wide range of challenges.
Fortunately, I worked with a great team who showed resilience and dedication, despite working in a remote location under high pressure. The project manager was based in Darwin while the rest of the small team was in Adelaide River and Sydney. We needed to manage frequent communication between a large number of stakeholders with diverse interests.
Can you give an example of some of those challenges?
The project was challenging because we had to rethink the methodology and the way in which materials and equipment were used. We had limited space within an already congested compound, a significant number of approvals and major scope creep.
There was variable concentration of iron and manganese in the raw water so the fully automated system had to integrate with the existing pumping and storage available on site. We also integrated a new asset with an existing system (SCADA programming).
We required meticulous design considerations to improve the overall process treatment while minimising negative impacts and effects associated with the changes.
What are the next steps for the project?
Following validation and process stabilisation, Power and Water is now assessing the water treatment plant performance to capture accurate data about filter performance, chemicals consumption, sludge production and operating costs.
Eric Vanweydeveld won Engineers Australia Northern Division’s Young Professional Engineer of the Year in 2015.
Image supplied by Power and Water Corporation: Adelaide River Water Treatment Plant.