Clean water: a pinch of salt and lots of ingenuity
25 September 2012
A group of GE engineers get together in their spare time to design and build an inexpensive water purification device for a rural Ugandan community.
One day last November, GE engineer Steve Froelicher got a phone call from Sister Mary Ethel Parrott, a nun, a teacher and a physicist who helped set up a boarding school for girls in rural Uganda. She needed clean water for her Ugandan pupils and Froelicher, a senior product architect who designs washing machines and water heaters at GE Appliances in Louisville, had just the thing for her.
For a whole year, Froelicher, his colleague Sam DuPlessis, and two GE retirees had volunteered every Wednesday night inside Froelicher’s Louisville garage, building an inexpensive water purification device the size of a tea kettle for WaterStep, a local charity. The device uses a car battery, a couple of electrodes, table salt, and some basic chemistry to make chlorine from brine and kill pathogens in polluted water. “The gas mixes with contaminated water much like carbon dioxide mixes with soda pop,” Froelicher says. “In Uganda, they can get their hands on salt, but they can’t get their hands on much more. With salt, a car battery and some solar panels you could be making clean water for years.”
WaterStep, which is working to provide clean water to people in Haiti, India, Pakistan and 23 other developing countries around the world, estimates that a child dies every 20 second due to a waterborne illness and that 1.2 billion people, one sixth of the planet’s total, lack daily access to safe drinking water.
Froelicher and DuPlessis first heard from WaterStep in November 2010. A cholera epidemic had just hit Haiti. The non-profit was looking for a rugged, portable device made from ordinary materials that could treat 1,000 gallons of water in less than an hour. They started by asking a lot of questions. “We had to learn many details that were not part of our jobs,” Froelicher explains. “I’m not a chemical engineer and neither is Sam. Like any typical new product development, we had to go back to school to understand what we were trying to do to make an excellent device.”
Within weeks, they were making prototypes inside Froelicher’s garage, a basic handyman’s workshop with a vice, a drill, a saw and a handful of other woodworking tools. This turned out to be a blessing. “By limiting ourselves, we developed a simple design and assembly techniques,” DuPlessis says. The team went through a “battery of testing,” Froelicher says. When one prototype was too small and another too large, they made a third that was taller. They manufactured six protypes before they settled on a design.
The device fits inside a 10in PVC cylinder with two plastic tubes attached at the top. It strips chlorine from salt water by applying battery voltage across a circular membrane, a process called electrolysis. The chlorine bubbles off one of the electrodes and floats to the top where the device captures it and mixes it with contaminated water. The chlorine begins to oxidise organic matter and kills the pathogens in the water. The water is usually safe to drink two hours after chlorination.
In November 2011, a group of Louisville doctors serving in a flooded area in Pakistan asked WaterStep for 50 chlorinators. The GE volunteers moved production from Froelicher’s garage to the non-profit’s small workshop. “We did a five-week crash course in building these things,” DuPlessis says. But the Pakistan team got their order. Each device traveled as a kit of some 100 parts inside a rugged tote. “The kit has tubing and clamps, spare parts and all kinds of stuff they need to build a mini-water treatment system,” Froelicher says. “You can check it like luggage.”
After the first order, more GE volunteers signed on. The sourcing team jumped in, talked to suppliers who either discounted or donated materials for the cause, and slashed material costs by 50 percent. A lean manufacturing team set up a production line that could scale from making ten chlorinators per day to producing hundreds if required.
Froelicher and DuPlessis are now working to reduce the required battery power from 120 watts to 25 watts. Sister Mary Ethel’s school in Uganda can already recharge its chlorinator battery from a solar panel. Says Froelicher: “If we can pull that off, we can run the device on a very small solar panel practically anywhere in the world.”