Originally reported and written in June 2023, this story has been republished as part of our archival content.

Dr Prasanna Jogdeo, a marine biotechnologist, first learnt about duckweeds while pursuing his master’s degree from the University of East Anglia in the United Kingdom back in 2009–10.

“As a part of the course, we were supposed to do a six-month research project. I chose to do a project with Professor Keith Waldron at the Institute of Food Research (IFR), Norwich. The project was titled ‘Starch Optimisation in Lemna minor’, a species of duckweed. Upon learning about duckweed, I understood its magic, potential for wastewater treatment and as a protein supplement. Duckweed was something which hooked me on to the subject of phytoremediation,” says Jogdeo, speaking to The Better India.

But what is phytoremediation? According to the Nature journal, it refers to the “use of plants and associated soil microbes to reduce the concentrations or toxic effects of contaminants in the environment.” In duckweeds, which float on or just beneath the surface of still or slow-moving bodies of freshwater and wetlands, he found a nature-based solution for the growing requirement of wastewater treatment and rejuvenation of dying water bodies.

Following his master’s, Dr Jogdeo came back to his native Pune as a lecturer at the renowned Fergusson College in 2010. Here, he met his student Pooja Tendulkar and introduced her to the duckweeds. Their shared fascination with duckweeds prompted a couple of collaborative projects in Pune and extensive research on how they can be used for wastewater treatment.

In 2013, Prasanna went to Nanyang Technological University (NTU), Singapore to pursue his PhD. Despite spending the next four years working towards his PhD, the collaborative work and discussions with Pooja continued, and soon the idea of Lemnion took birth.

This collaboration eventually resulted in the creation of a startup in 2018 called Lemnion Green Solutions. The name ‘Lemnion’ comes from a family of duckweed called Lemnnaceae.

“We started the company based on our shared fascination for duckweed and its potential for wastewater treatment. However, we went ahead and acquired more exposure. When we went beyond just wastewater treatment and into the ecological rejuvenation of water bodies, we realised that duckweed was only a part, albeit important, of the process,” explains Jogdeo.

Today, the Pune-based startup provides a range of services including ecological rejuvenation of water bodies (rivers, nullahs, ponds) and biological systems to treat wastewater.

Lemnion works with both businesses and governments, and has completed about 30 projects which include ecological rejuvenation of targeted stretches of nullahs and rivers ranging from 100 m to 2,000 m, and biological systems to treat wastewater of capacities ranging from 1 KLD [kilolitres per day] to 3,000 KLD across multiple geographies, particularly in Maharashtra.

“Use of duckweed can be one of the many interventions employed in the rejuvenation of water bodies. Ecological rejuvenation is a holistic and multidisciplinary process,” says Tendulkar.

Duckweed is an excellent phytoremediator (plants that uptake nutrients from wastewater). It’s the smallest angiosperm, which grows/floats on the surface of the water and accumulates nutrients through the roots. It also grows really fast, doubling its biomass in 48 to 96 hours. They also accumulate nutrients from wastewater and convert them into protein. “Duckweed contains up to 40% protein, a composition similar to that of soybeans,” she adds.

“When employed for treatment of wastewater, the system is designed with enough retention time (approximately four days) of water for efficient treatment, and duckweed is inoculated in the system. As duckweed covers the entire water surface in the system, around 75% can be removed every other week after use, and employed as manure for the garden,” says Dr Jogdeo.

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