What are the challenges of supplying recycled water?
Population growth means an increased demand on drinking water supplies, and a greater need to use the ‘right’ water for the ‘right’ job.
Providing recycled water to customers is one way utilities are working to address this increased demand.
While previously less understood by the general public, recycled water is becoming more accepted and usage for industrial purposes is gaining momentum. It is also already being used for agricultural applications.
But supplying recycled water comes with a number of challenges, including cost, complex treatment processes and stringent regulations, which utilities are working to overcome.
“We not only monitor the product quality of all our current treatment plants, but for new treatment plants that are being built we have some involvement in getting approvals or endorsement from the EPA and the Department of Health allowing us to provide recycled water to our customers,” said Yunal Kumar, an operations team process engineer with South East Water in Melbourne.
Kumar, who is also a member of the Australian Water Association's Water Recycling Specialist Network, works within a subset of the South East Water Technical Support team focused on recycled water quality, which is important to monitor and control for recycled water users.
The recycled water starts as a combination of domestic sewage and industrial waste that is treated to standards classed from A through to D.
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South East Water produces Class A recycled water – which has been treated to a high standard – for use in agricultural production for micro-herbs, fruits and vegetables, and industrial applications such as mining and manufacturing.
It also produces Class C recycled water, which is not used for food crop production, but can be used for irrigation and non-food-based agriculture.
South East Water operates eight water recycling plants, five of which use tertiary treatment processes to produce water to a Class A standard.
“Because of the nature of the water source (sewage and industrial waste), it undergoes several treatment processes to meet EPA and Department of Health standards, as they need to endorse the recycled water management plan before it’s sent to customers,” Kumar said.
Class A recycled water is treated to a standard where incidental contact with the product does not pose a risk to public health. This is necessary as Class A recycled water often comes into contact with people; manufacturing companies might use recycled water to wash equipment, or farmers might use it to water produce.
Kumar works very closely with the EPA and the Department of Health to ensure their standards are met.
“South East Water is working with labs and service providers to streamline the validation process for our treatment processes, which in turn means the cost factors in these areas will become more manageable,” he said.
Producing recycled water can be challenging, but with the evolution of technology, over time it will become cheaper and easier to produce, more accessible, and more acceptable in the community.