Delhi Lieutenant Governor, Vinai Kumar Saxena on Saturday visited the Neela Hauz Bio-diversity park developed by the Delhi Development Authority (DDA) in South Delhi. Walking through the scenic "Constructed Wetland System (CWS)", the LG described it as an exemplary model of urban rejuvenation and appreciated the DDA for developing and maintaining the park. Upon witnessing the natural water treating system that includes in-situ remediation of sewage water through two oxidation and stabilisation ponds, filtration zone and aquatic plants without using any power, and the quality of treated water, Saxena instructed officials to explore the possibility of developing such systems over other major drains in the City. "Visited Neela Hauz Bio-diversity park- an exemplary model of urban rejuvenation developed by DDA.
Constructed Wetand Systems like Neela Hauz, apart from being ecologically sustainable, can also be an effective means of treating drain water before its discharge in the Yamuna, the LG tweeted.
Neela Hauz Biodiversity Park has been developed as the Neela Hauz Lake, which is a natural waterbody and used to supply drinking water to South Delhi, is nearly extinct or dead due to urbanization and construction of Aruna Asif Ali road bridge across the lake by PWD.
According to officials, the Lake has been restored to its pristine glory through desiltation and excavation of solid waste dumps and in-situ biological remediation of 1 MLD of raw sewage – the only source of water to the lake.
“The novelty of Neela Hauz Biodiversity Park is the development of integrated Constructed Wetland System (CWS) – a nature based solution for in-situ remediation of raw sewage – and use of treated water for restoration of the lake, which was a nearly extinct lake. The CWS design works on the same principle as that of STP without energy. The CWS design has two oxidation/stabilization ponds, a filtration zone, constructed Wetland with aquatic plants and natural wetland,” said the official. “The integrated wetlands make 1 MLD of raw sewage into clean water which has the same quality as that of river water and all the water quality parameters (dissolved oxygen, pH, total suspended solids, total dissolved solids, Biological oxygen demand, chemical oxygen demands, ammonia, nitrogen and phosphates) are lower than the permissible limits prescribed by CPCB," said the official.
"The removal percent efficiency of CWS for some water quality parameters like COD is more than 15 per cent and the DO level is enhanced from 0.0 to 7.5 mg (L),” the official added.