A NEW chapter in groundwater treatment and resource allocation started a couple of months ago, aiming to improve the potential use and benefits of groundwater.
A small reverse-osmosis (RO) plant was installed on September, in a small plot of land at Century Orchards, in Loxton, with the objective of identifying different pathways to diversify water sources and relieve resource pressure on the River Murray.
Researchers from Adelaide University have conducted different projects in which they were able to determine that the Murray-Darling Basin has at least 80,000GL of underground water contained in aquifers, with 2000GL of that reserve having the potential to be sustainably extracted on a yearly basis.
The project at Century Orchards has developed an environmental potential for the Riverland due to its unique treatment of leftover brine, which is being injected back into an existing underground saline aquifer, storing it safely underground and reducing maintenance and environmental costs.
Project Leader Michael Leonard said “the unique potential of the project is that unlike most inland RO plants, which treat leftover brine in a series of evaporation ponds that keep salt on the surface, this project injects it into an already saline aquifer that stores it safely underground.”
“The importance of brackish groundwater for the Riverland is enormous because farmers can reduce their dependence on the River Murray, alleviating the pressure on the most important water source in the state,” Mr Leonard said.
“In the medium term, helping business being more resilient is a key thing with this project and protecting them from a drought with the transformation of water sources.”
Reverse-osmosis desalination has proved to be a trustworthy source of water supply, with desalination plants topping up reserves in coastal cities, but when it comes to the aquifers of the Murray-Darling Basin, reverse osmosis – which pushes saline water through polymeric membranes at extremely high pressure – has long been considered too expensive in energy-efficiency terms.
“There has been relatively not too much investment in understanding the actual opportunities and challenges associated with this water source from different economic, social and environmental viewpoints,” Mr Leonard said.
Century Orchards CEO Brendan Sidhu said “the trial will provide a gamechanger for us, which would not have been possible without One Basin’s multidisciplinary connections – linking some of the country’s leading groundwater hydrologists with regulators and the Adelaide-based desalination pioneer, Osmoflo.
“Bringing all these leaders together has produced something with significant implications for the greater good, with all our partners in this project committed to the same goal, which is protecting the precious fresh water that we have to share,” he said.
During the first month of the project, more than 30 farmers and water managers started visiting the site, with the Loxton trial having a big impact, locals were interested in learning about the process and its future implications of small-scale desalinisation used to water almonds, vines and essential crops, with most of the focus going into the details of the technology and how it can reduce operating costs.
The project has defined four main objectives:
- Develop a working prototype of an online resource and cost calculator for a range of water-user profiles to assess the viability of using marginal quality groundwater for irrigation and other consumptive purposes.
- Identify and scope a pilot case study that investigated the technical feasibility, economic viability, and the environmental sustainability of using brackish groundwater.
- Synthesise information on brine disposal options associated with enhanced use of brackish groundwater.
- Identify future research, training, and commercialisation priorities to support the sustainable use of marginal groundwater in the Murray-Darling Basin, including the utilisation of brackish groundwater, and other alternative water sources such as municipal and industrial wastewater.
