Using capacitive deionisation for inland brackish groundwater desalination in a remote location

In this work, a portable prototype of capacitive deionisation (CDI) unit has been used first time in Wilora, a community in a remote area in Northern Territory, Australia, to remove salt from the brackish groundwater. The CDI unit has demonstrated sufficient salinity and hardness removal ability at the remote brackish water source. It was found that increased flow rate resulted in a decrease of the overall total dissolved solids removal efficiency. However, in terms of energy efficiency, a higher flow rate tended to be favourable. With the current CDI unit configuration and local water conditions, 7 L/min is recommended as the optimal operational parameter, with an energy consumption of around 1.89 kWh/m3 of treated water. The total water recovery rate was between 75 and 80%. The electrosorption of NaCl onto the CDI cell assembly of 100 pair electrodes follows Langmuir adsorption isotherm and the pseudo-first-order adsorption kinetics. The portable CDI unit proves to be a viable alternative solution to brackish water treatment, especially in communities in remote areas where building a reverse osmosis treatment plant is not practical. The data and results shown in this work can be used as guidance for the on-site operation using this emerging technology.

► Trial of CDI has been conducted in a remote brackish ground water site in Australia.
► CDI has demonstrated sufficient salinity and hardness removal ability.
► The optimal flow rate and energy consumption are determined.
► CDI electrodes follow Langmuir isotherm and the pseudo-first-order kinetics.
► CDI offers a viable alternative solution to brackish water treatment.