Delhi L-G directs DDA to replicate Neela Hauz-model to restore city’s wetlands

Anil Baijal, who visited the Neela Hauz Biodiversity Park on Saturday morning, also directed the DDA to provide basic civic amenities — such as toilets and benches for sitting — for all citizens visiting the lake.

Delhi Lieutenant Governor Anil Baijal directed the Delhi Development Authority on Saturday to replicate the Neela Hauz Lake model of south Delhi to revive other wetlands of the national capital.

Delhi Lieutenant Governor Anil Baijal directed the Delhi Development Authority on Saturday to replicate the Neela Hauz Lake model of south Delhi to revive other wetlands of the national capital.

Baijal, who visited the Neela Hauz Biodiversity Park on Saturday morning, also directed the DDA to provide basic civic amenities — such as toilets and benches for sitting — for all citizens visiting the lake. Possibilities of setting up a refreshment corner will also be explored, Baijal said.

“The L-G has directed us to replicate the model of Neela Hauz Lake while reviving other water bodies in Delhi. We are also going to provide toilet facilities and seating arrangements in the biodiversity parks,” said Tarun Kapoor, vice chairman of DDA.

The lake, located adjacent to Sanjay Van, once sprawled over seven hectares and was the source of water for large parts of south Delhi. It was, however, reduced to less than 3 hectares and had become a dumping ground before restoration.

The DDA, in collaboration with the Centre for Environmental Management of Degraded Ecosystem (CEMDE) at Delhi University, revived the lake with the help of constructed wetlands in ??.

The constructed wetland system is similar to a natural wetland but is engineered for efficient treatment of sewage. It is an alternative to the conventional technology used to treating sewage and waste water.

“The constructed wetland at Neela Hauz comprises oxidation ponds, where microbes first break down the organic material in sewage water. Thereafter, the water is passed through physical treatment tanks where pebbles of all sizes, simulate a riverbed and filter the water further to bring down the amount of suspended solids. In the last stage at least 25 species of aquatic plants and microbes further biodegrade the remaining pollutants. The water, which comes out, is almost crystal clear,” said CR Babu, professor emeritus at CEMDE.

While the water before treatment had almost zero dissolved oxygen (DO), which fishes and other organisms need to survive, the water after treatment has nearly 8mg/litre of DO. The Biochemical Oxygen Demand (BOD), which indicates the level of organic pollution, was found to be more than 80mg/lit before treatment. But after treatment it had dropped to around 4 mg/lit making the water habitable for fishes and other aquatic animals, said Babu.

The park now boasts of a wide range of flora and fauna with dozens of species of migratory birds arriving in large numbers. There is also a butterfly corner.

The L-G also asked the DDA to document the process that was used to revive the lake. This could serve as a reference for policy makers, experts, NGOs and others when a lake needs to be restored in future.

“The model used to restore the lake inside the Neela Hauz Biodiversity Park is at presently treating one million litres of sewage and waste water every day. Not only it is cost effective but as the system uses only naturally occurring materials such as plants and stones and it requires zero energy,” said Faiyaz Khudsar, scientist-in-charge of Yamuna Biodiversity Park.