Archive for January, 2009

Could nanosensors be effective in detecting arsenic in water?

Thursday, January 22nd, 2009 by

Toxins in drinking water supplies, such as arsenic which affects millions of people living in the Bay of Bengal area, pose a dual problem.   First how to remove the toxins.   Second how to detect, or sense, the presence of the toxin with reasonable accuracy and repeatability.   Most existing methods of sensing the presence of arsenic are either expensive or do not give a reliable measurement.

Reading in the above context a report in the MIT Technology Review dated 20 January 2009 gives cautious hope.   It states that, “researchers at Penn State University have come up with a way to guide single nanowires into place on a silicon chip using an electric field.   Once the nanowires are in place, the researchers deposit electrodes on top to make arrays of sensing devices.”   This could pave the way towards cheaper hand held sensors.

So why only cautious hope?   Well, lessons from history tell us that developing the technology is only one step.   For it to be used effectively requires many partnerships to be made with key stakeholders.   Prime amongst these are the communities themselves who need to feel that they have a choice over the technology used and a voice in its development.   The scientists and researchers are urged to reach out to the end users so that the technology might meet their real needs.

For more information about the work of Practical Action in this area, see our web pages on nanotechnology and water.

Can new technologies become the “salt of the earth”?

Thursday, January 15th, 2009 by

There seems to be a fair degree of consensus around projections that suggest a rapidly increasing demand for water resources.   For exampe Lux Research predicts that by 2030 there will be a 40% increase in demand for water.   At the same time it is also clear that with climate change the supply of water on the earth is reducing, especially in many developing countries.   Current technologies are challenged to deliver an adequate supply of water, especially if constrained by the need to reduce carbon emissions.

In this context, there is room for some guarded optimism at the press release yesterday by QuantumSphere.   They have developed a positive osmosis process to desalinate water.   When compared to the traditional reverse osmosis process they claim a 70% reduction in energy consumption.   The press release makes no mention of safety nor does it specify any test results for possible toxic outcomes.   So salt of the sea may very well provide more drinking water in the future but to be the salt of the earth the companies involved need to be humble in their claims about new technologies.