DJB plans to use treated wastewater for lake, water table recharge

In an action plan submitted to the central government, the Delhi government stated that of the 701 MGD (million gallons per day) of available treated wastewater, only 125 MGD is currently being reused in the city. Under the 1994 Yamuna water-sharing agreement, 267 MGD of treated water must be mandatorily discharged back into the river to sustain its flow.

At a time when Delhi reuses only a fraction of its treated wastewater, the Delhi Jal Board (DJB) has proposed an ambitious plan— directing highly treated waste water not just to irrigate greenery in parks and farmhouses, but to recharge wetlands, lakes and depleted groundwater systems. The move aims to lift the city’s sinking water table, officials said on Thursday.

A government official said the projects are designed to revitalise natural ecosystems while boosting groundwater reserves. (Representative photo)

In an action plan submitted to the central government, the Delhi government stated that of the 701 MGD (million gallons per day) of available treated wastewater, only 125 MGD is currently being reused in the city. Under the 1994 Yamuna water-sharing agreement, 267 MGD of treated water must be mandatorily discharged back into the river to sustain its flow.

Detailing reuse plans for the unutilised surplus, the DJB said that around 100 MGD of treated effluent is produced at the Coronation Pillar sewage treatment plants (STPs), Phase 1 and 2. Of this, only 21.5 MGD is currently being used for horticulture. The board has now proposed three new reuse projects to channel the remaining volume.

“The remaining 78.5 MGD will be reused through three targeted projects: 28.5 MGD to recharge the marshlands at Coronation Pillar, 30 MGD for groundwater recharge via the Jahangirpuri drain, and 20 MGD for Bhalswa Lake and the adjoining golf course,” the status report said. It added that in-principle approval has already been received from the Delhi government.

A government official said the projects are designed to revitalise natural ecosystems while boosting groundwater reserves.

The DJB is also scaling up reuse for large urban water bodies and strengthening supply buffers through groundwater extraction in select zones. “We also plan to use highly treated water to develop large lakes across the city. Parallel efforts are underway to install hundreds of tube wells in high water table areas, from which groundwater will be drawn to supplement Delhi’s drinking water supply. Tender bids have already been invited for building the water conveyance systems for Bhalswa Lake and Sanjay Lake,” the official explained.

Separately, the DJB will divert 75 MGD of highly treated water to seven major water bodies: 10 MGD for Sanjay Lake (Kondli), 10 MGD for Smriti Van, 15 MGD for Rohini Lake No. 1, 5 MGD for NTPC Eco Park, 20 MGD for Okhla Lake, and 15 MGD for Rohini Lake No. 2, the plan said.

“Rohini Lake No. 2 and the Okhla Lake projects are scheduled for completion by December 2026, while the NTPC Eco Park is already 77% complete,” the status report added.

Another environment department official said that DJB has approved a policy to supply treated effluent for irrigation, including to farmhouses for horticulture, to reduce dependence on bore wells.

“This will significantly reduce the use of bore wells and groundwater for greening in the city. Groundwater recharge work is already underway at multiple sites, including Yamuna Vihar, Dwarka’s Pappankalan, Najafgarh, Keshopur, Rithala and Kondli,” the official said.

The DJB has also launched treated effluent supply schemes for farmhouses in Mehrauli, Kapashera, Narela and Okhla. “Treated water supply to farmhouses will help curb groundwater extraction and reduce bore-well use for horticulture and landscaping,” the official added.

(Independent comment)