New Zealand chemists learn new way to convert groundwater into drinking water

Sponsored by

Wellington, New Zealand, Oct. 25, 2012 -- Chemists have discovered an innovative method for treating bore water in New Zealand and converting it into safe drinking water.

They’re currently trialing the system known as Perforated Electric Flow Through (PEFT), on a Waikato farm as a low-cost solution for developing countries where many people have limited access to clean and affordable water.

Associate Professor Alan Langdon and Post-Doctoral Researcher Hilary Nath from the University of Waikato decided to try using electrochemistry to remove the iron and manganese prevalent in bore water from Waikato’s peaty soils. In turn, the residues give the water its typical brown-orange color and generally make it undrinkable without expensive treatment using aerators, filters, ion exchangers and tanks, according to a Waikato statement.

Researchers came up with a simple system that uses electric current passing between two perforated titanium electrodes to turn naturally-occurring chloride ions in the water into chlorine.

The chlorine then oxidizes and precipitates out the metal contaminants and also disinfects the water passing through the system, making it safe to drink. Best of all, the whole system can be powered by a car battery.

The researchers noticed that the closer together the two electrodes were positioned, the higher the electric field generated between them. And the higher the electric field, the more potent the chlorine being produced.

The two together were so powerful that they could kill bugs in the water at much lower chlorine levels than normally required -- the electric field was able to puncture the membrane of a bug making it 100 times more susceptible to the disinfecting effect of the chlorine.

At slightly higher applied voltages, the PEFT cell can also disinfect water by the electric field alone, with no need to produce any chlorine.

“By bringing the electrodes closer together than anyone else has been able to we can reduce electrical resistance and consume less power,” said Nath. “And because the flow path through the cell is very short, we can achieve good water flow at modest pressure.”

A prototype will be on show at the University of Waikato stand at Equidays next month. Langdon and Nath are now testing the prototype and getting good results -- they’ve seen total oxidation of iron during their trial.

“The initial focus will be disinfection of harvested rain water, disinfection of water supplies derived from surface water and bore water contaminated with iron -- we need to be very sure our technology is robust before contemplating overseas markets, particularly in developing nations,” added Nath.

###

Sponsored by

TODAY'S HEADLINES

Chilean mine contract kick-starts Degremont’s mobile water business

Chilean mining company SCM Minera Lumina Copper Chile has awarded French company Degremont a contract to supply 50 m3/hour reverse omosis mobile water treatment unit...

Drinking water access to be improved in Myanmar

SUEZ ENVIRONNEMENT's engineering subsidiary SAFEGE has been selected to support the Green City project for Myanmar's second largest city, Mandalay...

Oil sands tailings reclamation to be improved with novel solar energy-driven process

University of Alberta civil engineering professors have developed a novel technique that uses solar energy to accelerate tailings pond reclamation efforts by industry, ultimately helping to make the cleanup process of oil sands tailings more environmentally friendly.

MWH to support implementation of capital improvement plan for FL county

The Palm Beach County Water Utilities Department of Florida has awarded a contract to MWH Global to assist in delivery of the company's 2015-2020 capital improvement plan as owner's advisor.

FOLLOW US ON SOCIAL MEDIA