Cob-alt purification

She is one of the youngest Indians to receive a prestigious award on an international platform for her innovation. Meet 13-year-old Odisha girl, Lalita Prasida Sripada Srisai, who recently won the Community Impact Award at the Google Science Fair in California for developing a low-cost, bio-absorbent-based water purifier.

A Class IX student from Damanjodi in Koraput district in Odisha, she bagged the award in the 13-15 years age group. As a part of this award, Lalita received $10,000 as prize money.

Talking about the competition, she says, “It was during the national level CBSE Science Fair that I got to know about the Google Science Fair. People told me to think and prepare well before applying. But my mentor Pallabi Mahapatra motivated me to give it a try. It came as a surprise when I got selected in the top 20. I just wanted to showcase my work on a global platform — winning or losing was a secondary concern.”   

Inspired by Dr M.S. Swaminathan, the father of the Green Revolution in India, she wanted to address issues pertaining to the day-to-day life of rural people.

Talking about her motivation, she shares, “I have been visiting nearby villages and observing their lifestyle for a few years now. They live in harmony with their surroundings by utilising natural resources, without affecting the ecological web. Their lifestyle revolves around agriculture and cultivating many varieties of crops. This developed an interest in me to focus on science and develop something new related to agriculture.”

Lalita with a corn farmer at a farm in Odisha

With the help of her teacher and mentor Pallabi Mahapatra, she started working on one of the major global concerns — contamination of water.

According to her, rapid development is one of the prime reasons for the contamination of air, water and land resources. Pollutants released from various sources like domestic, agricultural and industrial sectors have dramatically modified the quality of water. She decided to work on something that will separate the pollutants at the source level to control water pollution.

“My study is based on the scientific principles of absorption by immobilising the contaminants with the help of corn cobs, as they are the least utilised part of the maize plant and a very important agricultural waste. Having high mechanical strength, rigidity and porosity, they can act as a suitable absorbent. That was the prime reason for using corn cobs as a material for the project,” Lalita explains and adds, “This enables contaminants like oxides of salts, detergent, suspended particles, coloured dyes, oil and grease to be absorbed in the surface of the corn cobs. Some of the heavy metals are also absorbed.”

For the experiment, the young student started collecting the cobs from a nearby farm and sun-dried them for a month. The pith of one cob was removed to make a hole at its centre, and 50 ml of domestic effluent collected from a kitchen drain pipe was poured into it. This was allowed to pass through the hole and the collected filtrate was then tested for purity.

“If the drain pipe of the household is connected to a chamber having different layers of corn cobs in partitions or to an S-trap pipe having corn cobs, they will separate more than 70-80 per cent of contaminants including suspended particles from the waste water,” she explains.

After this pilot stage, water with several added chemical impurities was passed through five bottles, each containing a different layer for purification.

Explaining the technique further she says, “The layers had various pieces of long, small and powdered corn cobs as well as activated charcoal made from them, along with fine sand. The charcoal layer was observed to absorb most of the coloured substances present in the water, while the chaff layers of both long and small pieces of corn cobs absorbed the suspended particles. The powdered corn cob layer absorbed the gasoline waste.”

According to her, this cheap and eco-friendly way of purifying water will open up a new market for corn cobs that are otherwise discarded as bio-waste.

“This technique can be used for immobilising the contaminants in domestic and industrial effluents, and in ponds, reservoirs and water tanks.”

Currently, she is working on her project and hoping that soon, every part of the country will have access to pure drinking water. In the future she wants to work on making a practical difference to the community by addressing issues on the environment and health.

She says, “I want to become a scientist working towards environmental conservation, making the world a better and healthier place to live.”