Pedal Power: How the Aquaduct Filters Water
The Aquaduct offers a solution to a specific problem: It increases accessibility to water and provides a means of sanitization to reduce the presence of deadly water-borne diseases. Since the intended Aquaduct riders live in the poorest areas in the world, the designers understood that a plausible solution would have to be simple and innovative. Perhaps that's why there's nothing particularly innovative about the components of the Aquaduct Mobile Filtration Vehicle prototype. You take the basic mechanics of a bicycle and a water filter and combine the two into one machine.
Aside from the tricycle frame, the main parts of the Aquaduct are:
- Holding tank on the back of the vehicle
- 2-gallon (8-liter) removable clean tank on the front below the handlebars
- Belt drive
- Clutch attached to an idler pulley
- Peristaltic pump
- Carbon filter
The tubing that the water moves through runs from the holding tank on the back of the Aquaduct to the circular peristaltic pump where the pedals are located. Then the tubing traces back to the holding tank to the carbon filter and back out to the clean tank at the front of the Aquaduct.
In order to get that water moving from the holding tank to the clean tank, you must pedal. The rotational motion of pedaling drives the peristaltic pump action that directs the water flow. Peristaltic pumps move liquids via compression and suction. When the pump turns with the pedaling motion, it compresses the tubing. As it continues to rotate, it releases the compression, creating suction and drawing water through it. Think about dunking a disposable water bottle into a pool. If you squeeze the bottle while it's submerged and then release it, that suction forces the water into the bottle.
Continuous pedaling allows the pump to draw the dirty water from the holding tank and push the water through the filter and onward. The activated carbon in the filter cleans the water by a process called adsorption. During adsorption, molecules from volatile organic compounds, chlorine and other chemicals cling to the carbon particles, removing them from the water [source: Lenntech].
If you reach your destination before you've filled up the detachable clean tank on the front of the Aquaduct, no problem. Release the clutch to relieve the belt tension and disengage the pedals from the wheels [source: IDEO]. Once you do that, you can pedal the stationary bike to filter more water. After you've filtered the water, you detach the clean tank from the bike and carry it wherever needed.
In an age of mindboggling gadgetry, the Aquaduct design stands out for its minimalism. Yet, the main downside to the Aquaduct is that people in the Third World probably won't be pedaling their way to cleaner water anytime soon. Like many useful products, the Aquaduct in its current form is still too pricey to become a practical vehicle in developing countries. This is a common hurdle when designing technologies for the Third World.
But the Aquaduct project hasn't been canned. According to the design team's blog, they're searching for a cheaper and more efficient filtration method instead of the carbon. In addition, the wave of positive attention it's received since claiming the Innovate or Die title could get the wheels of Aquaduct project rolling. After all, there are 1.1 billion reasons to turn the prototype into a reality.