Nanotechnology is one of those big words that intimidate normal people. Ironically, it refers to really small things. Nanotechnology is a field of activity where dimensions and tolerances are in the range of 0.1-100 nm. A nanometer is very small, it is one-billionth of a meter. A single strand of hair is 100,000 nm wide. One blood cell is 7500 nm, while DNA is just 2.5 nm. Nanotechnology is the application of these nano-structures and principles behind them to make nano scale devices and to produce new materials.

The discipline emerged initially in the 1980’s, gaining importance in the beginning of the 21st century. Although there has been much hype about the potential applications of nanotechnology, most current commercialised applications are limited to the use of "first generation" passive nano-materials. These include titanium dioxide nano-particles in sunscreen, cosmetics and some food products; silver nano-particles in food packaging, clothing, disinfectants and household appliances; zinc oxide nano-particles in sunscreens and cosmetics, surface coatings, paints and outdoor furniture varnishes; and cerium oxide nano-particles as a fuel catalyst. Nanotechnologies can also help alleviate water problems by removing water contaminants including bacteria, viruses, arsenic, mercury, pesticides and salt. A range of water treatment devices that incorporate nanotechnology are already on the market, with others either close to market launch or in the process of being developed.

The availability and access to safe drinking water, especially amongst the poor is an issue that is accelerating with time. Many water sources are contaminated with both biological and chemical pollutants and new problems such as arsenic contamination and increasing salinity are affecting water sources extensively. Over 21 per cent of India’s diseases are water related and one in four children worldwide who die before the age of five die of water related diseases. In spite of such alarming statistics, studies across North India show that water treatment is not practiced by the majority (73 per cent) of the people. Besides the myriad contaminants that make water unsafe, the per capita availability of water amongst the poor in the country, even in urban areas, is very low. Thus, there is an urgent need to address the issue of safe water among the Bottom of Pyramid (BoP) populations.

Nanotechnology offers an opportunity to effectively address this challenge. Many researchers and engineers claim that nanotechnologies offer more affordable, effective, efficient and durable ways of achieving this. Using nano particles for water treatment will allow manufacturing that is less polluting than traditional methods and requires less labour, capital, land and energy. Materials at the nano scale often have different optical or electrical properties from the same material at the micro or macro-scale. For example, nano titanium oxide is a more effective catalyst than micro-scale titanium oxide. It can be used in water treatment to degrade organic pollutants. Nano catalysts owe their better catalytic properties to their nano size or to being modified at the nano scale. But in other cases, the small size of manufactured nano particles may make the material more toxic than normal.

In India, the use of silver nano-particles for purification is the most popular due to its anti-bacterial properties. Additionally, silverware has been used for centuries by the wealthy in India to drink water; this factor could make it simpler to demystify the technology and increase demand. Researchers at IIT, Madras have worked on this technology.

Researchers at the Indian Institute of Science, Bangalore, are developing an immobilisation technique for degrading organic molecules using nano titanium dioxide. A water filter under development at Stanford University uses a piece of cotton treated with nano-material (silver nano wires and carbon nano tubes) to remove bacteria from water quickly by killing it with electrical fields using just 20 % of the power required by pressure-driven filters. Researchers at the Nanotechnology and Integrated Bio- engineering Centre (NIBEC), University of Ulster are working on are working on solar disinfection of water using photo catalytic nano-particles (titanium dioxide) to remove chemical pollutants and pathogens from water, for developing countries. A study by Indian Institute of Technology (IIT), Kharagpur has synthesised iron oxide particles using chemical method for arsenic removal.

A few of the technologies in the Indian market are mentioned below:

At the International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), the conventional method of ceramic candle filtration has been combined with nanotechnology to produce nanosilver coated Ceramic Candle Filters. In India, several people depend on these filters because they remove turbidity – but by adding nanosilver into the same material, water is also being disinfected from bacteria, providing a low cost and convenient solution. The only disadvantage is that chemicals, if present, remain.

The Tata Swach which comes at three different prices – Rs658 (£9), Rs866 (£12), and Rs1200 (£17) with a purification cost per litre of 10 paisa is a viable option for the BoP market. This filter uses silver nano particles infused in rice husk ash to purify water. It is non-electrical and It has a simple fuse mechanism for end of use/replacement indication that automatically shuts of water flow as soon as the purifying power of the filter bulb is exhausted.

Several simple and innovative solutions using nanotechnology have been developed around the globe. Examples include a sachet from Stellenbosch University, South Africa that can be fitted in the neck of a bottle containing ultra-thin nanoscale fibres which filter out contaminants plus active carbon granules which kill bacteria. A ‘teabag’ that can be dipped into household water supplies for about 15 minutes before drinking that contains a low-cost synthetic clay – hydrotalcite that attracts arsenic and removes it from water, developed by Australia’s Commonwealth Scientific and Industrial Research Organization (CSIRO) is another such example.

In India, nanotechnology for safe water is predominantly at the laboratory stage; however some systems for water purification are at the development stage, whereas some have reached the market. Brands such as Kenstar, Philips, Thermax, TATA and Eureka Forbes all have products in the market that apply some form of nanotechnology. Industries and Research Institutions have come up with viable products and although these have taken time, issues such as Intellectual Property Rights have been settled amicably. Given the perceived risks to environment and human health, the Indian government has stepped in by deciding to put in place a regulatory body. As nanotechnology is also being used for medicine and health, policy makers in the government insist that the technology must be used safely and there should be greater awareness about nanotech products.

However, as far as the BoP market is concerned there are few nanotechnology- based products that have made any impact. Nevertheless, if some of the barriers of awareness and latent demand can be addressed; there are certain feasible nanotechnology applications that could provide significant benefits to the BoP. There is a need to develop sustainable and innovative business models for these technologies. Cross-subsidising costs between the rich and poor communities can offer a solution. Mass production will also lead to models becoming more affordable. Thus, nanotechnology has a huge market potential that can be exploited to cater to the needs of the bottom of the pyramid populations. q