Australian researchers report portable CDI trial

A portable capacitive deionisation (CDI) desalination unit being developed and tested by the University of South Australia has demonstrated sufficient salinity and hardness removal ability.

The trial, at Wilora, a remote community in the Northern Territory, is supported by the Australian National Centre of Excellence in Desalination (NCEDA), which reported on the research in the 5 March 2012 edition of Desal Directions.

The CDI research is being led by Professor Linda Zhou, whose work was featured in D&WR‘s August/September 2012 article on the NCEDA. Her team, with USA researchers Dr Wei Zhang and PhD student Mohamed Mossad, have conducted a series of trials to evaluate the performance of a portable commercial CDI unit developed by Texas-based Aqua EWP (supplied by LT Green Energy).

The trials found that the CDI unit demonstrated sufficient salinity and hardness removal ability at the remote brackish water source. The increased flow rate tends to decrease the overall TDS removal efficiency. However, in terms of energy efficiency, a higher flow rate tended to be favourable.

At the existing CDI unit configuration and local water conditions, the researchers recommended 7 L/min as the optimal operational parameter with an energy consumption of around 1.89 kWh/m³ treated water. The total water-recovery rate was between 75% and 80%.

Zou says the current portable CDI technique offers a viable alternative solution to brackish water treatment, especially in remote area communities where building large treatment plants, such as reverse osmosis, is not practical. She says the data and results shown in this work can be used as guidance for onsite operation using the current technique.