19 July 2018
Water suppliers may soon have more effective ways to assess the performance of water filtration systems in drinking
water treatment for their communities.
A recent Ministry of Health report on drinking water suppliers showed 19 % of the populations surveyed were exposed to
water that does not meet safety standards.
An ESR study is using innovative new technology to test the efficiency of filtration systems commonly used in community
water supplies and domestic point-of-use filters.
A study using a pilot plant installed at Invercargill’s Branxholme Water Treatment facility has been running for the
last 16 months.
ESR’s Dr Liping Pang is leading a Health Research Council funded study using “surrogates” that mimic the physical and
chemical properties of pathogens likecryptosporidium and rotavirus, which cause gastroenteritis.
Cryptosporidium alone is estimated to affect around 1000 people annually.
Pathogenic protozoa, bacteria (such as some strains of E.coli ) and viruses found in drinking-water can cause waterborne illness. However current tools for assessing the
effectiveness of microbial removal in water treatment are limited to testing for E.coli and “turbidity” – a measure of water clarity.
Dr Pang says that studies overseas suggest that protozoa like cryptosporidium can break through treatment filters and
the absence of E.coli – which is an indicator of faecal contamination – is not a guarantee that there are no cryptosporidium or viruses in a
water supply.
Dr Pang and her team have developed surrogates for Cryptosporidium, rotavirus and adenovirus and norovirus. The tiny biomolecule-modified surrogates are harmless and inexpensive. They
are tagged with DNA markers or dye to see if they are being removed by the filtering processes.
Working with the water industry, Dr Pang’s team have been demonstrating the new surrogate technology in actual settings,
including pilot-scale sand filters in a drinking-water treatment plant and point-of-use domestic filters.
The new technology will help the country’s water suppliers to assess the performance of their current filtration systems
in order to ensure the safety of community drinking water supplies.
ENDS