Part 3 - Review of TATA Swach

TATA entered the lucrative Water purifier market in 2010 with its revolutionary Tata Swach Model, developed by Scientists at TATA Chemicals.  Its salient features are -

• Does not use Electricity or Battery
• Portable
• Cost Effective
• Does not require Running water

Let us analyze the constitution of this Water purifier.  For any one with no access to pure filtered water, any purifier is certainly better than no purifier at all, so from that standpoint, TATA Swach provides access to clean, filtered water to millions of rural Indians.

TATA Swach does not use any of the following methods (that most of its competitors use) for its purification -

• Ultraviolet disinfection
• Activated Carbon Filter
• Reverse Osmosis
• Chemical disinfection

Instead TATA uses a in-house developed filter that is composed of natural ingredients such as Rice Husk ash impregnated with nano silver particles according to a company press release dated 9 Dec 2009.

Let us understand the role of silver in water purification. Silver by itself can be harmful if consumed with water. The US Environmental Protection Agency (EPA) registers all filters with added silver as bacteriostatic, and it does not endorse these methods for reducing bacterial levels in the filter, or in water.  So a bacteriostatic filter is not safe to treat microbially unsafe water.  Silver is typically used to prevent growth of micro-organisms on any medium, but by itself, Silver does not kill any micro-organisms. Our worry is there are no laws in place in India that restrict filter manufacturers from ensuring that no silver gets released into the water.

US EPA's Office of Water also classifies Silver as a Group D Carcinogen in 1988.  So, please dont get carried away by terms such as nano silver particles.

Whichever filters use Silver impregnated particles as part of the filtration mechanism should also inform customers not to use hot water as they are likely to erode the silver particles from the filter.

While we have not broken apart and analyzed the filter cartridge, we assume that their filter does a good job of filtering out solid particles and certain bacteria.  Our opinion is such a filter can only filter out certain solids, but cannot kill or incapacitate smaller bacteria and other viruses. Silver coated nano particles can at best prevent growth of any additional micro-organisms in the filter, but certainly cannot kill or stop existing bacteria or viruses to pass through.

So in summary, TATA Swach offers portability, and good value as an effective water filter where none existed before.  It offers freedom to use in places where there is no access to power. We also believe that it cannot filter out certain bacteria and viruses based on its filtration mechanism. As of the publication date of this blog, the reported price of TATA Swach is Rs 1000, and a replacement filter costs Rs 299 which is good for 3000 litres (Rs 0.10/litre estimated operating cost)

After we conduct a full test on the water, we would report additional findings.