Purifying the purifier

Purifying the purifier

A consumer looking for a water purifier is most likely to be confronted with a fusillade of quality claims. K J Nath, president, Institution of Public Health Engineers in Kolkata is not sure about their veracity. "A lot of the tall claims by private players cannot be substantiated scientifically," he says.

Down To Earth asked a few manufacturers about the standards they adhere to. Most produced lab reports and rolled of terms like certified by nsf international usa, endorsed by the Indian Medical Association (ima), tested by university of Minnesota, bis certified, member of the Water Quality Association, usa.

What about the testing criteria at these national and international laboratories? We wondered. Our investigations revealed that these varied and were sometimes even irrational. A consumer needs to know the contaminant challenge, the quality and source of water, for which the purifier was certified. But consider, for example, a 2006 report by Spectro Labs Delhi. It stated that a model manufactured by Kent cleansed to packaged drinking water standards IS 14543 2004. Heavy metals were within limits stipulated by this standard, the report noted. But most heavy metals were within prescribed limits in the untreated water itself. So, the purifier had actually done precious little. It had only removed microbial contaminants, tds and salts. IS 14543 2004 standards also stipulate that there should not be any pesticide in water. But the Spectra Labs report made no mention of pesticide levels in the treated water.

We then decided to check on certificates issued by the Indian Medical Association. Were they also indifferent to the contaminant challenge? A certificate given by the association to Eureka Forbes in 2004 came as a revelation. It showed that the association actually does not test water purifiers. The certificate said, "Endorsements....(are) issued after examining all quality certificates obtained... from various labs and being satisfied about the same. ima endorses and approves the range of products mentioned above as being in conformity with the international standards for providing safe drinking water."

Standards don't account for changes in pollution profile

There are hundreds of other companies who claim substantial contaminant removal without any backing or certification. It is high time regulations were laid down to help the consumer make an informed decision.

Vacillating bureau
The Bureau of Indian Standards (bis) does have standards for some water purifiers like uv filters and candle filters. But these standards were developed between 1979 and 1999, when it was believed that water purifiers were meant to remove only bacteriological contaminants (see table Outdated and inadequate). Besides, these standards only apply to water that is free of chemicals and suspended matter. But as Nath points out, "Besides removing faecal coliform, water purifiers must also get rid of viral and parasitic pathogens as well as toxic chemicals like arsenic, fluoride and pesticides."

More importantly, the most sought after ro systems are outside the pale of standards.

Within the bis there is some awareness that the standards have not kept pace with changes in technology and pollution profile. The issue was, in fact, raised at the bureau's sectional committee meet on drinking water standards on February 5. But the priority seemed to be on revising drinking water standards. Prakash S Kelkar, chairman of the committee who also heads the Nagpur-based National Environmental Engineering and Research Institute's geo-environmental monitoring division said, "Drinking water standards (IS 105001991) in the country are much lenient compared to that set by the who or the us Environmental Protection Agency. Once we zero in on drinking water standards, we can move on to discussing norms for water purifiers." He did, however, suggest that "the first step towards setting standards is to have an independent and comprehensive assessment of the performance and claims of various filters."

Water purifier standards are also snagged because the bis can't seem to decide which of its divisions should take up the matter. Standards for uv filters were developed by the bureau's hospital equipment sectional committee, while those for candle filter were developed by ceramic ware sectional committe e. But there is no agreement on who should frame comprehensive standards in view of the changing market and the changing pollution profile (see box bis standard on drinking water).

What shall be the standards?
bis can draw lessons from international standards. A good example is the us standards drawn up by the ngo, NSF International. Water purifiers are certified for nsf standards by another not-for-profit group, the Water Quality Association. There are seven standards that cover a range of technologies and their performance claims. There are two sets of standards for carbon and ceramic systems that address health and aesthetic parameters.

Outdated and inadequate BIS standards on water purifiers need a revision Standard Salient features IS 147241999 Water purifiers with ultra violet disinfection Applicable to systems which rid water of water-borne pathogenic bacteria and suspended matter. Cannot filter dissolved solids or chemicals IS 74021986 Specification for filters for drinking water purposes Covers ceramic candle filters that remove suspended matter and bacteria. Cannot filter dissolved solids or chemicals. Materials used to make the filter should not mar drinking water safety. Filters must have information on the amount of water it can purify before it has to be cleaned IS 93101979 Specification for water purifier (electrically heated) Covers potable water purifier used for consumption in dispensaries, hospitals and in medicine preparation. Labels should contain instruction to boil water for minimum 30 minutes

The standards address the following issues

Product material safety The standards ensure that the product does not add any contaminant to water

Structural integrity The purifiers can work under high pressure

Literature and labelling They stipulate that there should comprehensive guides to aid installation, operation and maintenance. They also require that manufacturers corroborate performance claims with data sheets

Contaminant reduction claims A water purifier need not clean water of all contaminants. But manufacturers must specify the contaminants their products can check. There are different standards for different contaminant challenges. For example, standard number 53 applies to carbon and ceramic filters. Water purifiers can claim adherence to this standard if they cleanse 95 per cent of 300 parts per billion coliform. Pre-and post filters in an ro system must also be certified seperately.
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