Electrochemical Arsenic Remediation for Rural Bangladesh
"The Challenge"
In Bangladesh, more than 90% of the population depends on individual shallow tubewells for drinking water. About 10 years ago it came to be recognized that most of these wells are severely contaminated with arsenic, exposing 40-70 million Bangladeshis to a poison known to cause cancers in addition to a number of other debilitating and painful adverse health effects. The shallow tubewells are widely distributed among a diverse rural population, forcing water treatment to occur at the local level where it is traditionally least efficient and hardest to maintain.
Left: A Bangladeshi family around their tubewell, painted red to denote arsenic contamination. It is the family's only source of drinking water; Right: A Bangladeshi women shows the lesions on her hands, a typical symptom of arsenic poisoning. She recently discovered that she has cancer; Below: A small electrochemical cell is used to test arsenic removal via electrocoagulation. You can see the heavy rust buildup on the iron coil in the water and the orange tint from rust in the water – the rust binds to arsenic and is easily removed with a sand filter, leaving clear potable arsenic-free water. (Credits: Susan Amrose)
"The Opportunity"
Develop a low-cost technology for arsenic removal that is suitable for and efficient in small-scale operations in rural Bangladesh. Ensure that it is easy to maintain, uses locally available materials, has a reduced non-hazardous waste stream, and can be affordable to people earning less than a dollar a day.
"The Response"
A promising new technology, electrocoagulation, has been investigated as a tool for arsenic removal in Bangladesh. This technology has proven effective both in the laboratory and on a limited scale with Bangladesh water samples. Further research to advance this technology is underway. This technology can remove high amounts of arsenic from groundwater using only small amounts of iron and electricity as inputs. It is easy to maintain, uses far less iron than high maintenance passive techniques currently in use (and not performing well), and produces very little waste. Research using modern advanced techniques, such as X-ray Absorption Spectroscopy (XAS) and Cyclic Voltammetry, are being used to uncover the mechanism of arsenic removal at a molecular level, allowing for fine-tuning and optimization that will lead to an end product that can remove high levels of arsenic from drinking water for less than 1 cent (U.S.) per person per day, usingsolar-PV electricity costs. Specific research activities include:
- Batch tests to measure the arsenic removal capacity of electrocoagulation for a range of operating parameters in synthetic Bangladeshi groundwater;
- Proof of concept tests using real Bangladeshi water, collected by students in Spring 2007;
- High resolution XAS spectra of the arsenic removal process collected through multiple shifts at Synchrotron (ALS) facilities at Lawrence Berkeley National Lab and Stanford University’s Linear Accelerator (SLAC);
- Cyclic Voltammetry scans of the electrocoagulation process in synthetic Bangladeshi groundwater; and
- Fine-tuning and testing more efficient operating parameters informed by new knowledge of the arsenic removal mechanism.
Participating Faculty
Ashok Gadgil, Ph.D., Senior Scientist and Deputy Director Environmental Energy Technologies Division LBNL / Adjunct Professor Energy and Resources Group (Principal Investigator)
Robert Kostecki, Ph.D., Staff Scientist, EETD, LBNL
Venkat Srinivasan, Ph.D., Staff Scientist, EETD, LBNL
David Sedlak, Professor, Civil and Environmental Engineering, UCB
Participating Students
Susan Amrose, PhD Student, Physics, 2008
Kristin Kowolik, BS Student, Chemistry, 2008
Partnering Organizations
US Environmental Protection Agency
Lawrence Berkeley National Laboratory
Geographical Focus
Bangladesh