Circular Water Systems That Turn Risk into Long-Term Value

As part of expansion planning, it became apparent to this mining operation that excavation would intercept paleo-channels containing significant volumes of groundwater in the Macarthur River District. The water, which was contaminated with elevated zinc levels exceeding ANZECC discharge guidelines. Verterra was briefed to help resolve these issues with a cost-effective approach that would ensure a long-term, beneficial solution.  

Operating under a regulated Salinity Offset Scheme (SOS) to manage net salt export from their operations this client required an updated understanding of how much salt was being exported from the site - either through surface runoff or deep aquifer drainage. This was essential to ensure continued compliance with their Environmental Protection Licence (EPL) and to refine the size and scope of their Salinity Offset. 

To enable sustainable, large-scale irrigation using coal seam gas (CSG) water, this client required both rigorous technical assessment of candidate land and a well-prepared regulatory submission for a beneficial use approval. The project had to address marginal soils in a region with limited experience in intensive irrigation, while aligning with environmental safeguards and regulatory expectations. 

With planning underway for the staged development of up to 15 coal seam gas (CSG) wells in two Extended Production Test areas, the client sought an economically and environmentally sustainable option to manage the production of up to 1.8ML of highly saline and sodic CSG water per day.  

Rather than investing in expensive reverse osmosis or disposal pathways, a beneficial reuse option involving agricultural irrigation trials was proposed. To ensure success, the proposal required in-depth feasibility, design, and regulatory compliance support to assess viability and satisfy a Water Management Strategy and Environmental Authority conditions. 

With the population of the Caboolture River catchment expected to increase by over 100,000 people in the next 20–25 years, Unitywater faced a growing challenge: how to sustainably manage the effluent produced by the South Caboolture Sewage Treatment Plant (STP). Although effluent is A-grade and suitable for a range of non-potable uses, without intervention, the increased nutrient loading could threaten the health of the Caboolture River and downstream waterways. 

To address this, Unitywater launched the Wamuran Irrigation Scheme (WIS)—a circular economy initiative to beneficially reuse treated effluent in agriculture. Verterra was appointed to provide deep expertise in agronomy, irrigation, land capability, and environmental planning to help guide the project’s success. 

This client sought an innovative, sustainable, and community-aligned solution for the beneficial reuse of A-grade effluent from a Sewage Treatment Plant, located just 10 km upstream of a major drinking water supply dam. Rather than pursuing a conventional advanced treatment facility, Verterra delivered an award-winning, nature-based solution.

In regions of Australia where rainfall is unreliable, treated wastewater (effluent) is increasingly recognised as a valuable resource—particularly for irrigating tree crops and other vegetation. However, to safely and effectively reuse effluent for irrigation, its quality must be carefully monitored and managed. This case study demonstrates how Verterra approached successfully undertook risk assessment and development of a management plan that would enable its beneficial reuse for a forest plantation.

Northern Australia is considered a high-potential region for expanding irrigated agriculture due to the availability of rainfall and relatively undeveloped land. However, increasing land under irrigation can elevate the risk of sediment, nutrient, and pesticide runoff—particularly into sensitive waterways that feed into the Great Barrier Reef.  In this case study, Verterra demonstrates how a thorough understanding of environmental risk is the first step to designing irrigation schemes with minimal off-site impact.