A Big Idea to Tackle Global Water Contamination

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Dana Hernandez, Jay Majumdar and Chandra Vogt prepare an arsenic removal experiment by first measuring the initial pH of a synthetic groundwater solution. September 2019.

It began with a D cell battery, a couple of nails, and a styrofoam dinner plate in the garage of Professor Ashok Gadgil, a UC Berkeley Civil and Environmental Engineering faculty member since 2007.

Twenty years ago, Gadgil was struck by the problem of arsenic contamination in groundwater. By the early 2000s, the arsenic issue grew to affect about 100 million people worldwide. Today, that number has risen to 200 million. 

Arsenic is a potent carcinogen that can materialize in groundwater, highly toxic when the water is used for drinking purposes. The World Health Organization reports arsenic-contaminated water as one of the greatest threats to public health in the world. Arsenic is naturally present at high levels in groundwater in a number of countries, including Bangladesh, India, Mexico, and the United States of America. In most areas, the arsenic concentration in groundwater is low enough for safe consumption. However, groundwater in problem areas with higher arsenic levels need rigorous treatment, which is expensive or difficult to administer on a large scale.

“Nobody had solved the problem of removing arsenic in an affordable way, and that was a challenge that seemed worth tackling,” said Gadgil. “It seemed that this problem was just being ignored, or very unsatisfactory solutions were offered due to the political and economic powerlessness of these people.This is a classic situation we encounter around the world, and it doesn’t seem right.” 

In an attempt to find a solution, Ashok started experimenting with an idea that came out of MIT — allowing iron nails to rust in water and using that rust to capture arsenic. The problem was, this solution wasn’t viable on a large scale and failed altogether for high concentrations of arsenic. The rate at which iron nails rust is small compared to the rate at which arsenic must be captured from the water that flows past the nails. The MIT system works only for marginally elevated arsenic contamination, and that too works only on very small scale flows.

In that garage, Gadgil had an epiphany: electricity can be used to control the rate at which iron rusts. The iron nails became a long wire of iron and eventually, large steel plates. 

Susan Amrose, Case van Genuchten, Caroline Delaire, Siva Banduru, Sara Glade, and Dana Hernandez, UC Berkeley doctoral students, became interested in the issues related to the science, engineering, technology design, scale up, field testing, and full-scale implementation of the idea. All were, at one time or another, in the core technical team. Around that time, Hernandez scouted fellow students in a course offered through UC Berkeley’s Master of Development Practice to lead the business development and social impact evaluation aspects of the project. 

Their team currently consists of nine undergraduate and graduate students. Three team members are Civil and Environmental Engineering graduate students, four are engineering undergraduates, and two are computer science or data science majors.

Dana Hernandez gives a tour to visitors of the first large-scale ECAR plant in rural West Bengal, India. The tube settler shown allows for arsenic-laden iron precipitates to settle out while arsenic-safe water flows up. September 2016

The biggest initial discovery the team made was how to convert arsenic into its most capturable form: arsenic V. They discovered that arsenic III, which is extremely hard to capture, naturally converts to arsenic V through the iron rust process. After this discovery, there was no looking back; the ElectroChemical Arsenic Remediation project (ECAR) was born. 

“In many ways, we found lucky breaks that nature’s own chemistry provides, like the fact that oxygen from air dissolves in water naturally, which pushes arsenic III into arsenic V during natural conversion of iron rust in water from Fe(II) to Fe(III),” says Gadgil. “Nobody expected that and nobody knew that. But the point was to take calculated risks and try things. And here we are.”

Banduru joined the project in India as a field engineer in 2011, quitting his teaching job in the middle of the academic year. After two years, he came to Berkeley to do his Ph.D. work.  

“What motivated me to work on ECAR is the simplicity, effectiveness, and robustness of the technology,” Banduru says, now a postdoc at Berkeley. He is now the technical design lead of ECAR. 

Hernandez joined in 2016 after earning her masters at UC Berkeley as a field engineer, and is now a project director for developing and field testing more advanced versions of ECAR in California’s Central Valley.

“Being there for this phase of the project, seeing all the years of work, and then also addressing challenges that come up when scaling up a technology that works quite effectively in the lab but has unanticipated challenges in the field is very exciting” Hernandez says. “We solve those issues and adapt and work together in this very large, multidisciplinary team.” 

ECAR is meant to remove arsenic from large amounts of groundwater in an affordable, sustainable, and accessible way. It’s unlike any other arsenic removal systems in the market, as it is a zero liquid discharge technology (ZLD), the dream of all water-treatment designers. ZLD means that all incoming water molecules show up in the outcoming stream, with all contaminants removed as solids. ZLD effectively means there is zero water waste. Most ZLD technologies remain unaffordable, but ECAR is.  

In 2016, the team started field operations of their full-scale demonstration plant in rural West Bengal, India. In only nine months of monitoring, they demonstrated that the plant had reduced the arsenic concentration from 250 parts per billion in raw water to three parts per billion. ECAR’s technology has become an essential part of the local community. The plant sells arsenic-safe drinking water so that all costs are covered, and the operating company (an Indian licensee of the ECAR patent which is owned by the Regents of the University of California) gets a modest profit. More importantly, those living locally can purchase large quantities of water at a small fraction of their income. Safe drinking water that meets all relevant WHO, US EPA, and Indian regulations for drinking water is sold for about one cent US per liter. It’s a win-win for folks living in these communities.

Ashok Gadgil explains how ECAR works to students and teachers during the plant’s inauguration day at Dhapdhapi High School in West Bengal, India. July 9, 2016

The next generation of ECAR, called Air-Cathode Assisted Iron Electrocoagulation (ACAIE), was developed in 2019 with the help of the Big Ideas Contest, an annual competition based at the Blum Center at UC Berkeley and open to all University of California students.

“Big Ideas is extraordinarily important to get something done,” Gadgil says. “You need somebody who says, ‘Yeah, that might work, we’ll take the risk,’ because the impact might be very big and it’s easy for an idea to die at its most nascent stage.” 

ACAIE is designed to alleviate the arsenic problem in rural California. In 2020, the student team made new developments in the design and implementation of the technology’s reactors. Big Ideas Director Phillip Denny connected undergraduate engineering students to help the team create an app to remotely monitor voltage and current, which are important performance metrics of ACAIE.

Siva Bandaru secures the connections from the power supply to the 60 liter per hour ACAIE continuous flow-through system. July 27, 2020.

“The networking was key for me,” Banduru says. “We were able to reach out to other Big Ideas student winners when we were trying to scale up and received immediate feedback. That was really helpful in our thought process and implementation phase.” 

Though ECAR’s impact has already been massive for a local community, the team aspires to do more. The technology has the potential to dramatically reduce rates of excess internal cancers from drinking arsenic-bearing water. Drinking water with 100 ppb arsenic would cause 70,000 excess cancers in a population of one million. ECAR and ACAIE can bring that number down to 70. Twenty-one million excess deaths can be avoided. 

Big Ideas also helped to streamline the process of testing ACAIE in Allensworth, California. 

Gadgil maintains the journey towards creating and developing ECAR and ACAIE couldn’t have been possible without the interdisciplinary and ambitious student team, without Big Ideas, and without making a few mistakes along the way. 

“There’s a lot of very inspiring people who are so passionate about the work that they’re doing,” says Hernandez. “That just motivates me further to continue pushing our project forward and address the arsenic problem.”