Delhi govt plan to mix treated sewage with Yamuna water risky: Activists

The Delhi Jal Board’s (DJB) proposal to produce potable water from sewage treatment plants (STPs) after mixing the treated water with Yamuna’s water has raised eyebrows of city-based activists.

Yamuna Jiye Abhiyan convener Manoj Misra has written to lieutenant-governor Anil Baijal and chief minister Arvind Kejriwal, who doubles up as DJB chairman, saying the plan entails risk. Other experts also raised concerns.

“While on paper such a scheme appears to be attractive and sound, in reality it might be hugely risky and counter-productive and should not be implemented without rigorous background research and transparent public consultations,” Misra wrote.

Kejriwal had recently announced a scheme to release treated sewage water from two STPs at least 11km upstream of Wazirabad. The water after flowing downstream will reach Wazirabad from where it would be lifted again to be sent to treatment plants before being supplied to the city.

“This is where the problem lies. The water we lift from Wazirabad is totally clean. The DJB treats this clean water to be supplied to Delhi. Most of the pollutants Delhi adds to the Yamuna through its drains are downstream of Wazirabad. But now the government is planning to add STP water north of Wazirabad. This would compromise the water’s quality,” Misra said.

Dinesh Mohaniya, DJB’s vice-chairman, said: “We are already lifting water from the Yamuna and treating it in WTPs before being supplied to the city. The water we plan to release into the Yamuna would be treated. Cities like Agra, which are downstream of Delhi, treat polluted Yamuna water to be supplied to citizens. Other cities discharge untreated waste. We would release treated water.”

Misra said in the 1950s, there was an outbreak of infectious hepatitis after polluted water from the Najafgarh drain got mixed with river water at the Wazirabad water works. More than 3,700 people fell ill and 70 had died in 1955-56.

“Only 12 of the 41 STPs are working as per norms. With such a track record, how is the government feeling confident about mixing water from STPs with the drinking water resources?” Misra said.

“It won’t be right to compare the present scenario with 1950s as technology has advanced,” Mohaniya countered.

Vikram Soni, emeritus professor of physics and ecological wisdom at Jamia Milia and JNU, said: “This sounds to be an ill-considered and unfounded project.”

The DJB said a consultant would be hired to find out if the project is feasible.

The DJB’s project is in line with Singapore’s NEWater. But NEWater being ultra-clean is used mainly for industrial and air cooling purposes at wafer fabrication plants, industrial estates and commercial buildings.

“You are treating water at a STP and releasing it in the Yamuna, which has almost become like a drain. The entire effort at the STP goes to waste as the treated water when it mixes with polluted river water would become polluted again,” said SK Singh, head of the environmental engineering department at DTU.