Improving human health - in remote and developing communities
Contaminants such as arsenic, nitrate, fluoride and salt are present in much of the groundwater used to supply remote communities in Australia, China, India and many other places deprived of frequent, fresh rainfall. Such contaminants must be removed before this water is fit for human (or even animal or plant) consumption, but low cost, robust, sustainable technologies for doing this are few and far between. Until now…
BioGEMS colleagues Professor David Waite and Dr Peter Kovalsky, along with Professor John Fletcher from UNSW Electrical Engineering &Telecommunications, are working on the development of a low cost robust sustainable technology for effective water treatment. The main outcome is intended to be a solar-powered device for removal of salt and other contaminants from groundwater that is capable of stand-alone operation with optimal energy recovery and inbuilt monitoring – perfect for remote or developing communities around the world.
It is a low-energy technology that involves attracting charged ions to electrodes of opposite charge (sodium to the cathode; and arsenic, nitrate, fluoride and chloride to the anode). “Basically the technique sucks salts up like a sponge and results in treated water with much reduced concentrations of contaminants,” explains Dr Kovalsky.
In collaboration with Mincarb, an Australian company specialising in electrochemical water treatment, the development work resulted in a high impact Linkage Project research partnership funded by the Australian Research Council.
The project aims to identify applications where CDI could cost-effectively make brackish, contaminated water usable, and then optimise CDI design and operating conditions to remove particular ions of concern, and to develop approaches to energy recovery.
"While the core technology (of Capacitive Deionisation or CDI) has been around for a while, it’s becoming increasingly popular because it’s a low-energy technology and is also very scalable,” Waite explains. “If you want to build a small unit for a household, you can do that, but you can also scale it up to serve a community."
The device being developed by the research team uses both non-redox and redox processes, with the latter a focus for generating chlorine or hydrogen peroxide in the units.
"It’s a composite technology where we can lower the salinity, we can remove trace contaminants like fluoride and arsenic and nitrate, and also potentially generate disinfectants in the process,” Waite says.
In 2014 the philanthropic arm of Tata Group – one of India’s largest multinational conglomerates employing over 600,000 people - awarded the project grant funding to build units to treat water supplies in remote Indian villages without any mains power.