This paper from the Meridian Institute describes a range of well-known and field-tested conventional approaches to removing contaminants from water as well as the current crop of nanotechnologies that could enhance existing — or develop new — water treatment technologies.

For each approach or potential product the authors give a short description of what it is and who has developed it, and report on the product's effectiveness in removing contaminants, the amount of water it can treat, and its cost and ease of use. They also include summary comparative charts of conventional versus nano-based treatments.

Conventional approaches covered include various types of filters, ultraviolet radiation, chemical treatment and desalination. Nano-based water treatments covered include carbon nanotube-based technologies, nanofiltration membranes and devices, nanoporous materials and clays, zeolites, nanocatalysts and magnetic nanoparticles.

This report, prepared by the World Water Assessment Programme under UNESCO (UN Educational, Scientific and Cultural Organization), assesses global freshwater resources including what drives the pressures facing them, how water is used, climate change's future effects on water supplies and options for improving water management for sustainable development.

The authors highlight the increasing demand for water, outlining the demographic, economic and social factors — such as population growth, international trade and changing lifestyles. They argue that climate change will undoubtedly affect water resources, impacting water quality and the frequency of extreme events such as droughts or flooding.

Investment in the water sector is important, say the authors — to improve access to clean water as well as decrease pollution from untreated sewage discharge. International donors must play a part in improving water infrastructure in the developing world, they add.

But how individual countries respond will depend on their own development objectives, capacity and political framework. The authors outline options for policymakers to increase supply, manage demand, reduce losses and reallocate resources.

This report, published by the Meridian Institute describes the growing interest that developing countries, including Brazil, China, India and South Africa are showing for nanotechnology. It describes the ways in which nanotechnology applications could solve problems of health, sanitation, and pollution and provide faster, cheaper information and communication technologies.

The report also reviews the challenges of using nanotechnology for and in developing nations. Finally, it outlines the roles and responsibilities of different stakeholders in ensuring that nanotechnology moves forward responsibly.

The Meridian Institute says nanotechnology could play a role in achieving the UN Millennium Development Goals — a set of quantified development objectives to be achieved by 2015. As a result, governments of rich nations should dedicate a "reasonable" portion of their overseas development assistance to nanotechnology.

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