As a small girl, Lalita Prasida Sripada Srisai enjoyed long walks through her home country of India. She enjoyed seeing how the cultures varied between villages.
During her travels, she often encountered heaps and heaps of corn cobs baking under the sun.
Lalita wondered how they got there, and what could be done with them.
She discovered that the farmers who grew corn would skim the kernels for consumption and toss the unwanted cobs on the side of the road. Even the animals wouldn’t eat these dried up leftovers.
After a memorable encounter with a tribal farmer, Lalita had the idea to repurpose those abandoned, dehydrated corn cobs as part of a water filtration system. In the same way that a Brita filter traps unwanted particles as the water trickles into the pitcher, Lalita’s invention uses corn to sponge up dirt in greywater collected from kitchen drain pipes and also from natural ponds.
Monday, we caught up with the 14-year-old at the fifth annual Google Science Fair, a global competition and celebration of innovation, where she took home Scientific American’s Community Impact Award.
At age 11, Lalita started hacking corn in the kitchen. She picked some shriveled cobs from the road and placed them in a bowl of dirty water on the table. When she returned to check on the experiment, the water looked clearer.
Feeling like she was onto something, Lalita got serious. She collected corn cobs from local farmers, washed them thoroughly with water, and dried them in the sun. Meanwhile, she began construction on a filtration system that could use the cobs.
Today, the contraption stands well over her head: a thin metal rod with five spokes distanced about a foot apart. Attached to the end of each spoke is an upside-down plastic bottle with the bottom cut off. Straws extend from one bottle’s cap to the bottle underneath it.
Here’s a drawing of the system:
Each bottle contains pieces of dried corn cob of different sizes. As water pours into the top bottle and trickles down, specific contaminates are “caught” by the corn.
- Bottle 1: Whole pieces of corn cob catch particles visible to the naked eye.
- Bottle 2: Corn cobs cut into one-inch pieces trap smaller grains.
- Bottle 3: Corn cobs powdered into granular form absorb gasoline and oil.
- Bottle 4: Corn cobs burned into a blackened charcoal-like material soak up colour dyes and lead.
- Bottle 5: The catch-all, sand, grabbed remaining chemical toxins, both organic and inorganic.
Lalita took the invention to her school’s chemistry lab and performed the test again, this time running several qualitative tests on the water before and after filtration. She found that her system removed 70 to 80% of contaminates, including oxides of salt, detergents, oils, colour dyes, and other floating particles.
While physical particles of dirt aren’t great for your health, the big problem with dirty water is the disease-causing microorganisms that can live in it. To decontaminate the water, it can be boiled or iodine tablets can be added to it, Lalita believes.
Further chemical and physicals examinations are necessary before she can market it to farmers. She hopes that the tool will serve as a cost-effective solution for cleaning ground water and industrial tanks on their property.
So far, the response has been positive.
“They were really amazed that such a thing could even happen!” Lalita says of the farmers who gave her their used corn cobs.
Her appearance at the Google Science Fair should help. As winner of Community Impact Award, she receives $US10,000 in funding and a year-long mentorship from Scientific American.
Business Insider Emails & Alerts
Site highlights each day to your inbox.