Gilghi Off-Grid Water Treatment Solution

Water treatment is energy intensive and accounts for 13% of Australia’s electricity use. For remote communities with no connection to the main power grid, infrastructure overcapitalisation is unavoidable if wanting to produce a small-scale drinking water supply. Often the only viable solution is relying on alternative water sources, typically expensive transported water. Despite sinking a new bore in 2014, the Gillen Bore community relied on the continued transport (150km round trip from Alice Springs) of potable water due to high salinity, hardness and low pH levels in the bore water. Since installing Gilghi in 2019, potable water is now available.

The innovation addresses long-overdue water needs of remote communities through an opportunity Aurecon and Ampcontrol saw to combine engineering skills to remove a social inequality. It applies renewable energy technology and next generation power controls to provide clean water and streamlines the water-energy nexus. Comprising photovoltaic (PV) solar, batteries and back-up diesel generator, Gilghi takes feed water from numerous sources including groundwater, rivers, lakes and oceans and turns it into drinkable water compliant with ADWG. Coupling a small-scale water treatment system, including reverse osmosis (RO) and advanced filtration with an efficient power system has resulted in an inexpensive, off-grid solution.

Groundwater in arid areas contains high concentrations of naturally occurring minerals (nitrates, arsenic and uranium) and are often rated non-compliant to the Guidelines. Major water-related diseases in remote communities include diabetes, kidney disease, thyroid disease and cancer. As a result, most remote communities rely on potable water transported by truck, a costly and inefficient expense that in 2017 cost the Australian Government $13,800,000 in transportation fees. Gilghi pushes the boundaries of new/innovative ways to think about design and collaboration across sectors. Globally, the design tackles significant social, commercial and environmental issues by leaving a tangible positive impact on communities.

Project Gilghi was enabled by a $70,000 Municipal and Essential Services Special Purposes Grant from the Northern Territory Government through the Department of Local Government, Housing and Community Development. Gilghi’s flexible design enables the system to meet larger supply requirements and different treatment challenges without adversely affecting the cost per litre. Advanced filtration - source water is stored in an inlet tank before passing through three stages of treatment: 1. Media filtration (sand media, carbon and softener) 2. RO unit comprising of cartridge filters, pressure booster pump and RO membranes 3. An outlet tank and UV disinfection system Waste stream processing includes an evaporation pond to treat the brine from the RO process. In arid climates, residual saltwater can be used as a feedstock for succulents and to grow salt-tolerant plants. The unit uses a stand-alone hybrid power supply utilising: 1. PV solar is used to operate the treatment process and/or charge the backup battery system when required 2. Battery storage 3. Innovative electrical control system allows both AC>DC and DC>AC conversions 4. Diesel back-up generator Remote real time monitoring via 3G/4G or satellite facilitates a live user interface and alarming of the power system and water treatment process.