How Hauz Khas Lake got a new lease of life

If you want to know how to restore a dying lake, visit Hauz Khas Lake located inside the beautiful landscaped lush green Hauz Khas Park in South Delhi. An initiative started by Tarun Nanda, a foreign-returned environmental engineer has given a fresh lease of life to a dying lake which used to give a pungent smell.

Now showers a cool breeze to the utter amazement of the visitors who have seen the lake dying over the years due to encroachment and sewage dumping.

“In 2017, I managed to raise over `20 lakh through crowd funding and a corporate sponsor. Then we got permission from Delhi Development Authority to go ahead with the project. Since then I have carried out the construction of the largest wetland system in Delhi that has the capacity to purify over 2 million litres of water per day,” said Nanda.

Hauz Khas is a 14th century water body that was dug up to serve as a tank during Alauddin Khilji’s reign. “We have already eliminated the smell around the lake and now very little garbage or organic waste floats on the surface. We have created wetlands and the cleaned water that flows from them,” he said.

Tarun and his team have also completed construction of the wetland in the inlet channel that filters all the incoming water without chemicals, machinery or electricity.

“We have completed construction of a second wetland and will soon start its operation. This wetland will filter water from the lake and then return it. It is the first lake in Delhi, if not the whole of India, where water is pumped from the lake and fed into a filtration plant before being returned to the lake,” he said.

According to Nanda, the total area of the constructed wetlands is 425 sq m and it is likely the largest and most technologically advanced natural sewage treatment plant in Delhi.

“We used different wetland designs, including horizontal flow, vertical flow, sub-surface flow wetlands and surface flow wetlands. Even some portions of the wetlands change their function depending on lake level and inlet flows. The source of the water is a mix of partially treated and raw sewage. We also sensitise people not to litter in and around the lake and to preserve it,” he added.