Dartmouth Engineer - The Magazine of Thayer School of EngineeringDartmouth Engineer - The Magazine of Thayer School of Engineering

Students Invent Filter to Give Nepal Arsenic-Free Drinking Water

By Anna Fiorentino
May 2015 • CoolStuff

With the recent devastating earthquakes in Nepal, the goal of one Dartmouth engineering student team has become even more urgent: To provide the Nepalese with clean, arsenic-free drinking water.

Cancer-causing arsenic, which can’t be easily detected or removed by traditional filters, continues to show up in the drinking water of nearly half the households in both Nepal and nearby Bangladesh, with crippling mental and physical effects.

The student invention, called "SafaPani" meaning "clean water" in Nepalese, provides some hope. Created for Thayer's two-term engineering design sequence (ENGS 89/90), the project—part of Thayer's Cook Engineering Design Center (CEDC) and sponsored by the Dartmouth Class of 1980—offers a low-cost alternative to the expensive conventional arsenic filtration systems that often break.

"Following our 30th reunion, we decided to sponsor an environmental or humanitarian BE project," says Dartmouth Society of Engineers Executive Committee President Richard Akerboom D'80 Th'82 '85. "It proved popular with classmates, and our budget allowed us to continue so we have sponsored four more such projects since." This year they picked SafaPani.  

Thayer Class of 1980 check for SafaPani
The SafaPani team accepts the generous support of the Dartmouth Class of 1980. (l to r) Ron Menner, Dean Joseph Helble, Merle Adelman D'80, Cameron Crone Bilger D'80, Richard Akerboom D'80 Th'82 '85, Scott Hansen Th'15, Edward Stritter D'68, Jamie Potter Th'15, Julia Zaskorski Th'15, Brent Bilger D'80 Th'81, Stephen Jenkins Th'15.

Developed by Jamie Potter Th'15, Stephen Jenkins Th'15, Scott Hansen Th'15, and Julia Zaskorski Th'15, SafaPani uses the process of electrocoagulation to filter arsenic.

"Historically, these locals drank surface water. However, due to pathogen contamination, many wells were drilled into the ground water," says Potter.

Since 2008, a number of other ENGS 89/90 teams have worked on SafaPani, identifying and validating the arsenic removal process. It was Potter's group, though, that finally developed an inexpensive production model durable enough to withstand heavy use and simple enough to operate in tens of millions of homes in both Nepal and Bangladesh.

SafaPani arsenic filter
A SOLIDWORKS® model of the SafaPani arsenic filtration system. The rectangle pieces are the iron electrodes in the water that's on top of a layer of sand. Below the bucket is a reservoir that can hold up to 90 liters of filtered water. The whole system can be placed on cinder blocks or other type of stand to raise the bottom valve up for filling a pot or bottle.

The device is comprised of a series of nested buckets with valves, filters, and a custom electrical circuit to control the electrocoagulation process. SafaPani electrically releases iron ions into water. The iron ions react with the arsenic to form safe, larger molecules, which are then removed from the water through a sand filter. Flushing the water through a column of sand forces these large iron-arsenic complexes to become trapped in the sand, resulting in a flow of clean, filtered water at the other end.

"Our device holds clean water in a tank for the user," says Potter. "The entire process can take a few hours depending on the level of arsenic in the contaminated water."

Since it's onset, SafaPani was sponsored by VillageTech Solutions, a California-based non-profit that develops affordable technology solutions in third world countries, which is run by Thayer Board of Overseers member Edward “Skip” Stritter D’68 and David Sowerwine. Sowerwine co-founded the VillageTech Solutions with his wife Haydi in 1996.

Along with the CEDC, Dartmouth Class of 1980, and VillageTech Solutions, Dartmouth Humanitarian Engineering (DHE) also took a leading role. "Dartmouth Humanitarian Engineering, advised by VillageTech Solutions, has been the glue that has held the project together throughout the years," says Jenkins. "They have a subgroup committed to moving this project forward, and have made a lot of progress both on the technical side, as well as in developing a strategy to minimize the economic and social issues involved with bringing a product into a developing country’s market."

Last fall, DHE members representing SafaPani were one of four winning teams out of 21 to take home cash prizes and gain access to The Digital Arts Leadership and Innovation (DALI) Lab and Dartmouth Entrepreneurial Network (DEN). DHE has since tested and confirmed that the prototype successfully filters arsenic below the safety standard. DHE now plans to conduct field-testing in Nepal to validate the functionality of the arsenic filtration system's design and to learn more about how SafaPani will fit into a villager's home, and will soon begin fundraising for initial production.

"Every continent in the world has areas with high levels of arsenic in its groundwater," says Jenkins, adding that New Hampshire is one hotspot for arsenic in the US. "However, neither the Nepal and Bangladesh governments nor their citizens have the resources to filter their groundwater."

The World Health Organization set a safety standard of 10 parts per billion of arsenic in drinking water to be safe, but there are tube wells in Nepal with over 50 times that standard. Arsenic contamination is undetectable by the human body, and therefore contaminated water can look and taste completely clean. This naturally occurring toxic chemical that leaches into ground water can lead to cancer and diseases of the blood vessels, legs, and feet, and possibly diabetes, high blood pressure, and reproductive disorders.

"Millions of people in these countries drink this contaminated water over an extended period, and see the poisonous effects years later," says Jenkins.

Tags: design, humanitarian service, innovation, international, projects, students

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