TED Talk: Deepika Kurup, A 18-Yr-Old Girl Who Developed A Low-Cost Water Purification System
February 1st, 2017
The next generation scientists are already hard at work solving the biggest problems people facing. A good example will be a 18-year-old Deepika Kurup. Deepika is a high school student from Nashua, New Hampshire.
Every summer she and her family would travel to India to spend time at their ancestral home. While she was in India, her parents would always remind her to drink boiled or bottled water. It intrigued her when her parents would make sure that the water she drinks is clean. Soon she realised that not everyone is fortunate enough to enjoy the fresh and clean water.
Just outside her grandparent’s house, she would see people standing in long queues under the hot sun, filling buckets with water from the tap. She looked at the children filling bottles with dirty water from the streams on the roadside. This changed her perspective. This unacceptable social injustice compelled her to find a solution to the clean water problem.
She was curious to know why these kids lacked clean water, a substance that is essential for life and she realised that we are facing a global water crisis.
It was surprising as 75 percent of the planet is covered in water, and only 2.5 percent of that is fresh water. Less than 1 percent of earth’s freshwater supply is available for human consumption.
With rising population, industrial development and economic growth, demand for clean water are increasing, but the sources of fresh water are depleting rapidly.
According to World Health Organisation, 660 million people in world lack access to drinking water sources. This is the leading cause of death for children under the age of 5 in developing countries. UNICEF estimates that 3000 children die every day from water-related diseases.
After she had come back home one summer in class eight, she decided to combine her passion for solving the global water crisis with her interest in science.
She converted her garage into a laboratory and started reading many journals on water-related research. She learned that the developing countries use Solar Disinfection or Sordis method to purify water.
How does SORDIS work?
In SORDIS, clear plastic bottles are filled with contaminated water and then exposed to sunlight for 6 to 8 hours. The Ultraviolet radiation from the sun destroys the DNA of these harmful pathogens and decontaminates the water.
Shortcoming of the process
SORDIS is an easy method to use and energy efficient as it only uses solar energy, but it is a slow process and takes up to two days when it is cloudy.
To make SORDIS faster, she researched and found that the method of photocatalysis is more efficient. Photo means the sun and a catalyst is something that speeds up the reaction. She used photocatalysis to accelerate SORDIS process.
How does photocatalysis work?
When the sunlight would strike a photocatalyst like Titanium dioxide, it creates very reactive oxidants like superoxides, hydrogen peroxide. These oxidants can remove bacteria and organic contamination from drinking water.
Shortcoming of the new process
There were several disadvantages. The inside of the bottle is covered with the photocatalyst coating. This coating blocks the UV radiation and diminishes the efficiency of the process. Also, these layers are not tightly bound to plastic bottles which mean that they are washed off, and people end up drinking the catalyst.
Photocatalytic Composite Water Purification
Her goal was to overcome the disadvantages and create a safe, sustainable, cost-efficient and eco-friendly method of purifying water. And a class eight science project is now a photocatalytic composite water purification system.
The composite combines the titanium dioxide with cement which can be formed into various shapes. One can create a rod and put it inside a water bottle to purify drinking water. It can also be used as a cork which could filter water for families. It can be even coated inside the water tank to clean larger amounts of water for the community over a long period.
From a science project to social enterprise
Her journey was not easy. She was just 14 years old, and there was no sophisticated laboratory. But she did not let age deter her passion in pursuing science research to solve a global problem.
From her laboratory, she took this idea into the real world and started a social enterprise called ‘catalyst for world water’ which aims at solving the global water crisis.