Sustainable water supply for mid-coast NSW

Using digital technology saves resources

The $82 million Bootawa Water Treatment Plant in New South Wales treats all water distributed in the mainly residential region from Coopernook in the north to Tarbuck Bay (south of Forster). MidCoast Water built and opened the plant in 2010 to provide for the future sustainable water supply of the area.

The water treatment plant, located next to the Bootawa Dam, is capable of processing up to 60 million litres of water per day. It was designed to address the water quality problems of the past such as elevated iron and manganese levels, the presence of algae and dirty water after rain in the catchment.

Water, which can now be sourced from the Manning River or the Bootawa Dam via a raw water balance tank, is treated through a microfiltration process, ozone treatment, carbon filtration and chlorination before going into the reticulation system. During the filtration process, water is drawn through fine polymer membranes which remove fine particles and provide a physical barrier to achieve reliable removal of cryptosporidium, giardia and other harmful microorganisms without the need for chemicals.

The fully automated Bootawa DamTreatment Plant is monitored and run by SCADA technology and uses Allen-Bradley PLCs. Due to its compatibility, ifm efector’s AS-interface was used with the Ethernet IP gateway. AS-i is a patented protocol design optimised for digital signals. The advantage in using this protocol is that users are not restricted to using one product or brand, they can be mixed and matched.

UGL Infrastructure’s Senior Control & Instrumentation Engineer, Arjan Koolhaas, was involved with the construction of the project and implementing the digital network equipment. “The use of networks like Profibus, ethernet, DeviceNet and in particular the AS-i network has provided a sustainable solution for such projects,” he says.

“The digital equipment has allowed the project to be more sustainable by saving resources, allowing for better maintenance at the plant and also providing the ability for easy expansion in the future.”

According to ifm efector, installation and wiring of AS-i is where the main costs savings can be achieved due to fewer connections, no input/output cards and less cabling required. Koolhaas agrees saying: “During installation there was a significant reduction in the amount of cabling, which provided a saving in the use of valuable resources.

“The use of a fibre-optic ring network around the plant provides an energy-efficient solution for the transfer of data to/from the control system. Control loops are tuned in such a way that no unnecessary adjustments are made when process conditions are within a predefined deadband. This extends the life span of equipment such as valves, drives, etc and also saves on energy consumption.”