Susan Addy: Electrochemical Arsenic Remediation

  • United States

Electrochemical Arsenic Remediation

A method to safely, affordably, and effectively remove arsenic from drinking water using a small amount of electricity to create rust in contaminated water. Arsenic is a chemical element that occurs both naturally and as a byproduct of agricultural, mining, and industrial activities. The WHO-recommended maximum limit for arsenic in drinking water is 10 parts per billion (ppb). An estimated 140 million people in more than 70 countries are affected by toxic concentrations of arsenic in groundwater. In Bangladesh, for example, levels over 1,000 ppb have been detected.


Long-term exposure to arsenic in drinking water is associated with various forms of cancer and debilitating skin diseases. While the ideal solution to this problem involves providing an alternative water source, this is usually not an economically or logistically viable option. Freshwater sources in most of the arsenic-affected areas are bacterially contaminated from lack of sanitation infrastructure. While numerous arsenic remediation techniques exist, many of them are expensive and/or ineffective at decreasing the contaminant to acceptable levels. Other techniques are effective, but typically involve the use of highly toxic chemicals, which can damage both human and environmental health.


The Berkeley Arsenic Alleviation Group, a multidisciplinary team of students from UC Berkeley and the Bangladesh University of Engineering and Technology, is working with Dr. Ashok Gadgil and several advisors on ElectroChemical Arsenic Remediation (ECAR). The technique uses low voltages of electricity to create rust in contaminated water. The rust binds to arsenic, which can then be removed from the water through settling or filtration.

“Our system “shocks” the arsenic forcing it to bind with rust made from the other minerals in the water. Arsenic then gets transformed from an invisible foe into larger visible particles that can be removed easily and cheaply.” —Ashok Gadgil, Principle Investigator, UC Berkeley
The only equipment needed is a plastic tank, two steel plates, a small propeller to mix the water, and a source of electricity—which could easily be provided with photovoltaics. The process involves no corrosive or toxic chemicals, is very low cost, and needs no technical expertise to operate.


The goal of BAAG is to design completely automated (and, if appropriate, solar-powered) water treatment systems that pump groundwater and utilize ECAR to effectively remove arsenic from drinking water. They propose that such systems should be community-based, maintained by locally hired technicians, and supported by an educational campaign run by local social workers to instruct villagers on the importance of clean water. These facilities will be profitable and sustainable due to low overhead costs, and the low cost of ECAR. Community systems allow for centralized quality control and waste removal, both crucial to maintaining sustainable health impacts. In addition, the systems would be rapidly scalable to meet the enormous and pressing need.

The next steps for Dr. Gadgil and his team are to secure financial support for long-term field trials, and begin working with the private sector on scaling the ECAR technology.
“We’ve done the research, we’ve done the invention, we’ve filed the patents, we’ve done field testing, and we’ve shown that it works. Now we need help to make sure it goes into the hands of the private sector so it can scale up.” —Ashok Gadgil, Principle Investigator, UC Berkeley
In parallel, they would like to continue the scientific development of a new ECAR technique that uses higher current density to precipitate a different form of rust. According to Dr. Gadgil, it removes arsenic equally effectively, but in a matter of minutes rather than in an hour. It’s not only potentially more appealing to the private sector, but could also reduce operating costs.