Brainchild of a British environmental engineer, dozens of green patches are floating in the waterbody soaking up its pollutants

Dozens of floating islands have popped up across the Hauz Khas lake over the last few months.

These 2×2-metre green patches on the lake are floating on discarded plastic bottles, but wait before you jump to any pollution conclusion.

These artificial lakes are designed to soak up the lake’s pollutants and not add to it, as would be the popular guess.

In a bid to rejuvenate the lake, environmental engineer Tarun Sebastian Nanda and programme manager Debayani Panja, both associated with Evolve Engineering, have taken up the initiative to clean it up by floating artificial wetlands into the waterbody.

“When we first started the cleaning work, we could see the presence of algae across the lake. We even found dead fish stuck in plastic bottles. The idea behind the floating wetland is that the plants on the islands will absorb the nutrients present in the waterbody, thereby cleaning the lake in a natural way,” said Mr. Nanda, who came to the country from England eight years ago.

Agreement with DDA

The Hauz Khas lake, a 14th-century waterbody that was dug up to serve as a tank during Alauddin Khilji’s reign, had been dying a slow death over the years. The project started after Mr. Nanda signed an MoU with the Delhi Development Authority in August last year and the first island was floated into the lake in October last.

“We floated the island on Diwali last year. Wetlands are a good option for cleaning waterbodies as they are low-cost and need no maintenance. No machines are required for water purification,” he said.

Mr. Nanda and his team, including eight labourers, can be seen preparing the ground for cleaning an inlet that connects the lake to the water being released by a sewage treatment plant in south Delhi.

“We were not sure if the water released by the STP was properly treated. To ensure that properly treated water reaches the lake, we are in the process of setting up a constructed wetland near the inlet,” said Mr. Nanda, who had earlier used similar techniques at farm houses to reuse waste water for gardening purpose.

Crowdfunded project

The project, so far, has been a crowdfunded one with volunteers, including some schools, signing up to “adopt” these floating islands.

“The islands are built first and then placed into the lake. People who adopt them learn how to make them from scratch. Old soda bottles are used for floatation. However, we make sure that plastics which have adverse effects are not used. These floating islands will also act as a habitat for ducks and migratory birds that come in December,” explained Ms. Panja.

Diwali deadline

The MoU with the DDA states that “90% removal of pollutants within two months of operation” needs to be done.

Confident of fulfilling the terms, Mr. Nanda said, “Funding issues have slowed down the process but we will soon get corporate sponsorship. Once that happens, we will place 500 floating islands in the lake simultaneously and that will help the waterbody immensely. With a 90% reduction in pollution, even the smell that dominates the lake [at present] will be gone.”

On when he aims to achieve the target, he said,

“All the islands should be placed by Diwali this year. Water samples from various points in the lake and the inlet that is releasing the water from the STP will be collected to reflect the change in the water quality.”

Scepticism galore

The process of cleaning the lake has not been easy, say both the members spearheading the project.

“There is a lot of scepticism as nobody has seen the results yet. To actually prove that this is a sustainable method is a challenge. It takes time to convince people and often those who come here demotivate us. There are other regulars too, who tell us that the water around the islands is looking better. The very fact that the plants are growing is indicative of the fact that the nutrients and the algae from the water are being absorbed,” said Ms. Panja.

For Mr. Nanda this is a good chance to prove that the 15-acre lake can be cleaned through natural methods.

“We are here because there is a problem waiting to be solved. The idea is to turn waterbodies into ecosystems that can manage the waste. What is the point of complaining about the deteriorating environment if we cannot come up with a solution?” said Mr. Nanda.

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