SA Water’s research into nitrous oxide at its Bolivar wastewater treatment plant has been used by the United Nations (UN) to refine its guidelines on greenhouse gas emissions.
In a trial conducted in partnership with the University of Queensland, SA Water used floating hoods anchored at various points in its activated sludge plant to capture, monitor and understand nitrous oxide emissions in real time.
Using this data, the utility was able to optimise the treatment process, leading to a 30% reduction in nitrous oxide emissions, along with other plant improvements and energy savings.
Nitrous oxide is a by-product of biologically removing nitrogen from wastewater and is about 300 times more powerful in warming the climate than carbon dioxide.
SA Water Lead Scientist Environment and Wastewater Dr Ben van den Akker said the utility can now accurately predict nitrous oxide emissions at any of its locations at any time. This helps map emissions hot spots, which means it can better target optimisation and control measures.
The UN’s Intergovernmental Panel on Climate Change (IPCC) included the findings in refinements to its guidelines on greenhouses gases, published in May.
“The end result of this project has provided the most comprehensive data set on nitrous oxide emissions for step-feed activated sludge plants … and there is no greater recognition of the importance of this work on climate change than from the IPCC,” van den Akker said.
“We can now say we’ve positively impacted international climate change policy, which is a pretty cool thing for SA Water and South Australia.”
Director of the University of Queensland’s Advanced Water Management Centre Professor Zhiguo Yuan said nitrous oxide levels are a global issue.
“Combatting nitrous oxide remains a real problem facing water utilities globally, and this goes to show how improving a plant’s design and operation can make a real impact on reducing the emissions footprint,” Yuan said.
“Our work with SA Water on this project demonstrates the importance of researchers and industry partners collaborating to deliver real benefits to society.”
The technology was developed by SA Water’s commercial business unit, Water Engineering Technologies.