Marine biologist Dr Prasanna Jogdeo learnt about duckweeds while pursuing higher education from the University of East Anglia in the United Kingdom in 2009-10.
“Upon learning about duckweed, I understood its magic, potential for wastewater treatment, and as a protein supplement,” he says.
In duckweeds – which float on or beneath the surface of still or slow-moving bodies of freshwater and wetlands – he found a solution for wastewater treatment and rejuvenation of dying water bodies.
In 2018, he launched a startup called Lemnion Green Solutions along with his student Pooja Tendulkar.
“Duckweed is an excellent phytoremediator (plants that uptake nutrients from wastewater). It also grows really fast, doubling its biomass in 48 to 96 hours,” says Pooja.
“They also accumulate nutrients from wastewater and convert them into protein. Duckweed contains up to 40 percent protein, a composition similar to that of soybeans,” she adds.
Dr Jogdeo says, “When employed for treatment of wastewater, a system is designed with enough retention time (~ 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 percent can be removed every other week after use, and employed as manure for the garden,” he adds.
In addition to duckweeds, the startup also uses canna, taro, sedges, and grasses like vetiver and pampas.
Lemnion has completed about 30 projects, which include the ecological rejuvenation of targeted stretches of nullahs and rivers ranging from 100 to 2,000 metres.
It has also treated wastewater of capacities ranging from 1 KLD [kilolitres per day] to 3,000 KLD across multiple geographies, particularly in Maharashtra.