Delhi’s Mannat Kaur built a low-cost greywater recycling system that can save up to 6,000 litres/month, without major plumbing changes or expensive installations.
In 2016, a water disruption left Delhi homes dry for days. “I saw people struggling for two days during a supply disruption in Delhi’s canals,” says Mannat. That moment shaped her passion for water reuse and sustainable solutions.
After steady research, she created a model that uses a Scupper Valve to collect water from drains and a Bilge Vessel — a 3-bucket filter that purifies it using charcoal, orange peel, and pebbles.
Greywater from showers and kitchens is filtered naturally and stored. It’s reused for non-potable needs like mopping, gardening, or washing — no water goes to waste.
Her fully functional prototype is used at home and built with Arduino, floats, and 3D-printed parts. It’s been working seamlessly for two years, saving thousands of litres.
The system costs just Rs 2,000. “No plumbing changes are needed, and we can customise it for space and aesthetics,” says Mannat. It’s designed to be practical for any home.
Decentralised systems like Mannat’s cut emissions by 80 to 85% compared to central sewage treatment, reducing up to 18,000 tonnes of CO₂ yearly if scaled across cities.
Her invention also made her the first Indian to represent India at the Stockholm Junior Water Prize 2024. “The global feedback helped refine my system,” she says of her experience.
Mannat is now working to commercialise her model as a ready-to-use product like a water purifier. “My goal is to make this available off the shelf,” she adds.
Mannat’s story proves that smart ideas can start small. With a few buckets and a simple valve, her idea can help cities and households conserve water effectively.