From gully cricket to playing for India, Smriti Mandhana’s journey is remarkable  

Intergovernmental Oceanographic Commission, the harmful algae event database had record 9,503 events with impacts on human society. "It contaminates marine life and sea food," said the teenager, during her presentation for the 3M Young Scientists Challenge. She went on to develop a robot, and a film gel that can attract algae to a substrate. Her vision is to be able to clear the oceans of Harmful Algal Blooms by collecting the algae alive and converting it to biofuel.

Harmful Algal Blooms occur naturally in waterbodies, and can also be encourage dby human activities. Phosphate and nitrate runoffs from fertilizers, as well as from sewage and leachate (liquid from solid waste), along with excessive sunshine can cause harmful algal blooms to proliferate. They also ten dto prefer warmer, still and more shallow waters. Huge amounts of money are spent to clear water bodies of these HABs, the US alone spent $1.1 billion in 2020. Also, there are products to combat these blooms, but Moitri says they just aren't up to the mark, or are pollutants in themselves.

Moitri's solution

"I created a water soluble, biodegradable and positively charged gel with a citrate ion and citric acid," Moitri explains. The chitosan and citric acid contained in the gel induces coagulation in the algae. She spent a summer vacation experimenting with gels and substrates, transforming the family dining room into her makeshift lab. "These algal blooms are everywhere but are especially prominent in Florida," she explains.

Moitri's gel is designed to be biodegradable and water soluble, reducing its environmental impact. The chitosan polymer swells and carries the citric acid in water in the gel. The gel induced coagulation in the algae, causing it to clump together, become dense and sink to the bottom. However, the process also causes them to die. However the decomposition process depletes oxygen from the water, killing off marine life all around it.

A functioning prototype

Her 3M mentor, Dr Kannan Seshadri helped her with a turnaround. Moitri Santra realised that algae can be harvested to make biofuel, which comes with environmental benefits of its own. "I experimented with gels, powders and flakes and found that dried film gel floats effectively on water, and attract algae in under a minute. However, this requires a substrate material to trap the algae.  In her early version, Moitri had used a scotch brite sponge, which is a non woven material with intertwining fibres. "I experimented with around a dozen non wovens in rayon, viscose, wood pulp, PA and nylon," she explains. "I chose only the hydrophobic ones because the hydrophilic materials will soak up water and become heavy. Finally, she settled on PET non-woven material.

But after all this, how is the algae harvested? For this, she built SCARAB, an EV3 robot that can be deployed on a boat. The substrate is tied to spools and fastened under a 'guide' to hold the material in place. The material is coated with gel and when the motors are turn on, the spool spins slowly counterclockwise, ravelling and unravelling the substrate to collect algae. The material of the substrate also allows the algae to become trapped. "The algae are alive at the end of the process. I examined it under a microscope and it was clearly moving," she adds.

The 3M Challenge and Broadcom Masters

She attributes much of her success to her mentor, Dr Kannan Seshadri. "He helped me turn my simple idea into a functioning prototype," Moitri says. "I was thinking of sinking the algae and he allowed me to see that it could potentially cause more environmental harm." Moitri's next challenge is to remove the algae from the strip without damaging it, which she hopes to do with a primer. "If the right primer is used it can also increase the strip's reusability," she says. She hopes to see her innovation being deployed around the world, and the eventual use of this harvested algae in the making of biofuels.

In 2022, Moitri also placed second in the technology category at the Broadcom MASTERS, taking home a cash prize and the opportunity to attend a STEM summer camp. She decided to follow her interest in medicine and medical university at the University of Connecticut's Pre-College Summer Program for its pre-med focus. There, she spent her time attending lectures in the morning and taking practical lessons in the afternoons, exploring a different specialization everyday. "using mannequins, we did simulations of emergency situations," says Moitri, who has always been fascinated by the human body and its many complex functions.

s cleaned around 700 kilos of waste from a rivulet so filthy that people mistook it for a gutter.

Daughter of the earth 

A military brat, Sneha grew up travelling to various parts of the country, even though she was primarily in Vadodara. "I come from a joint family. My grandfather was also in Indian Air Force, and after travelling across the country my family decided to settle in Vadodara for it was a beautiful, quaint city," says the young environmentalist, who loves to travel. "I loved to go to national parks and zoological parks, and enjoyed spending time there. So, it was natural that I would develop an interest in working with the environment,” says Sneha, laughing as she recalls people’s surprise when she first told them her career choice. She stuck with it, though, enrolling at Maharaja  Sayajirao University of Baroda to pursue bachelor's degree in environmental science and later a masters in the same subject. And this is where her life took a turn.

A rivulet runs through it 

Her love for nature inspired her to enroll in UNEP’s Plastic Tide Turner Challenge, which began in her college in 2019.  Funded by the United Kingdom since 2018, the “Tide Turners Plastic Challenge” has reached over 225,000 youth in 25 countries in Africa, Asia, and the Caribbean. The initiative is a crucial element of the British government’s 25 Year Environment Plan to reduce ocean plastic.

 

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At 23, when she was doing her masters in environmental studies, Sneha led a campaign to clean a polluted rivulet that had been choked with plastic waste. Since the rivulet ran through their college campus, Sneha managed to round up 300 students for the campaign. They began cleaning what they thought was a ‘nala’ or gutter which was once said to have been home to several crocodiles. However, the crocodiles left, unable to withstand the mounting garbage. “We would make jokes about crocodiles living on campus,” Sneha says. “But that isn’t the issue, is it? The fact is that the stream belonged to the crocodiles and we ruined it.” The endeavour took months and the team had cleaned 700 kilos of waste by the end.

Braving the odds 

While the students worked day and night to clean the rivulet, they faced several challenges during the campaign. "The biggest task was to create awareness in the nearby localities about plastic waste. For most of them this nala had been a dumping place for years. The after-effects of such deeds were shared and it took some time to see them react positively," shares the environmentalist, adding, "Sometimes, the police would also enquire about our projects as they had never seen anyone bother to clean this stream."

 

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However, things changed slowly. "Today if someone throws plastic in the stream, the locals question them and ask them to pick up the garbage. They are very protective of the stream," she smiles. The environmentalist also points out that what amazed her the most was the interest shown by the local women. "We think they are mere housewives, but they are important stakeholders in society. When we were running the awareness campaign, I was amazed by how much they wanted to learn about the water bodies near their homes, how they cause flooding and pollution and its impact on their health," Sneha says.

Interestingly, after removing over 700 kg of plastic from the urban stream, many turtles and crocodiles found their way back to the water during the monsoon. "Many other insects and plants also grew in their surroundings," shares Sneha, who adds that the college authorities installed fences for the safety of students. Currently, Sneha's juniors are managing the programme, while she monitors them.

Against the tide

 

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Currently pursuing her PhD in Extreme Hydrological Events at ATREE, Bengaluru, Sneha is gearing up to work on restoring the Thamirabarani, Tamil Nadu’s only perennial river. "The project is only six months old and is still being developed," Sneha explains. The Thamirabarani, which is 128 long, "supports drinking water and agricultural activity," the environmentalist says, adding, "We want to install physical instruments to control pollution and also spread awareness on the harm it has caused. We want to impact the prevailing mindset."

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