World's first solar powered arsenic treatment plant



Professor Bhaskar Sen Gupta from Heriot-Watt University, together with the Bangladesh Green Energy Foundation, has opened the world's first fully autonomous, solar powered plant to safely remove arsenic from the water supply.

The technology has the potential to help millions of people who are being chronically exposed to high levels of arsenic in water on a daily basis.

The plant, in the Comilla District of Bangladesh, is now ensuring a safe supply to 200 school children and, within a year, will serve an additional 800 members of the local community.

The plant has reduced arsenic levels in the school's water supply from 239 micrograms of arsenic per litre to 2 micrograms per litre in just seven weeks. The WHO safe guidelines for arsenic in water are no more than 10 micrograms per litre.

Professor Bhaskar Sen Gupta explains, “Arsenic does not have any colour, odour or taste so affected communities are often unaware of the serious health risks associated with using contaminated water. It takes several years to observe the effect of chronic arsenic exposure.

“Arsenic in drinking water can only be detected by chemicals tests, which is difficult for rural communities that are located far away from testing facilities.

“The conventional technologies for arsenic remediation are based on a ‘pump and treat' method involving either adsorption or membrane processes. Such plants are expensive to run and have problems associated with waste disposal and maintenance.

“In contrast, our team has developed a Subterranean Arsenic Removal (SAR) or ‘In-situ treatment' which we first began using in 2008. It doesn't use any chemicals and produces no waste, making it a very low cost technology option for rural use.

“This is the first time we have created a treatment plant that is fully autonomous and solar powered.  This plant will operate entirely from a mobile phone app so will have no running costs for 25 years and doesn't use any chemicals. It also produces no waste.”

The project was funded by the Engineering and Physical Sciences Research Council (EPSRC) with logistical support and assets provided by the Bangladesh Green Energy Foundation.

More than 137 million people from 70 global countries are exposed daily to arsenic in their drinking water. Arsenic is highly toxic and is responsible for a variety of cancers in affected communities.

In the Indian subcontinent, nearly 70 million people are chronically exposed to high levels of arsenic in rice, milk, vegetables and drinking water. This is one of the reasons why it takes many years to identify communities affected by arsenic.

The technology is designed to replace expensive adsorption or membrane based processes where disposal of high-arsenic hazardous waste poses a serious problem.

A partnership of NGOs and academic institutions led by Bhaskar Sen Gupta has designed a low cost, environment-friendly technology for the subterranean treatment of groundwater for both drinking and irrigation purposes, which doesn't use chemicals or generate waste.  

This could have wide implications for the irrigation of rice, which can absorb high levels of arsenic from the ground.