Najafgarh drain’s biochemical oxygen demand reduces 40 points during lockdown: GMDA affidavit

The Najafgarh drain’s biochemical oxygen demand (BOD) has reduced by 40 points during the 21 days of the nationwide lockdown, stated the Gurugram Metropolitan Development

The Najafgarh drain’s biochemical oxygen demand (BOD) has reduced by 40 points during the 21 days of the nationwide lockdown, stated the Gurugram Metropolitan Development Authority (GMDA) affidavit submitted to the national green tribunal (NGT) on Wednesday. Prime Minister Narendra Modi ordered the lockdown to stem the spread of the coronavirus disease (Covid-19) in the country. It began on March 25, and the first phase ended on April 14.

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The BOD is an indicator of pollutants in water—the higher the level, the poorer the quality of water.

The NGT said it would review the affidavit after the second phase of the lockdown is lifted in May. The NGT has been monitoring Gurugram’s sewage discharge for the past four years. It has stated its concerns from time to time about the rise of pollutants in the drain and questioned the GMDA’s treatment quality and capacity.

Officials privy to the matter said that they measured the BOD level at 15 mg/litre on April 14, which is the lowest-ever measurement of the drain so far, according to Pradeep Kumar, chief engineer, GMDA. The officials measured it at 55 mg/litre on March 21. This reduction is a great improvement, which the affidavit stated began taking place soon after the closure of factories and commercial establishments because of the lockdown.

The Haryana state pollution control board (HSPCB) has issued certificates to industries, making it mandatory for them to treat effluents at the industry-level and then discharge them towards the CETP or STPs—where the GMDA further treats and discharges them into the Najafgarh drain that flows into the Yamuna river.

Pradeep Kumar, GMDA chief engineer, said, “We want the HSPCB to probe whether this improvement is linked with industries. All our STPs at Behrampur and Dhanwapur and the CETP at Manesar are still functioning well. Meanwhile, we have roped in Sri Ram Institute, New Delhi, to collect samples for testing. The treatment quality of our STPs has been questioned repeatedly after the measurement of every sample from the Najafgarh drain so far, because of high BOD levels.”

The NGT was to review the affidavit on April 15 but deferred it after the lockdown was extended till May 3 on Tuesday.

“Domestic discharge from the city (around 355 MLD) continues, while factory discharge is nil. The CETP at Manesar gets effluent discharge measuring around 55 MLD from industries, while the Gurugram industries’ effluent goes to STPs at Behrampur and Dhanwapur for treatment. That the BOD level has gone down establishes the fact that several industries must flout rules and discharge effluent or waste directly into drains leading to the Najafgarh drain through private tankers. The HSPCB can confirm that,” Kumar said.

The NGT is concerned about pollution in the Yamuna because of the continuous discharge of polluted sewage by Haryana, Uttar Pradesh and Delhi, and is monitoring the same through a committee—the River Yamuna Pollution Monitoring Committee—constituted in June last year.

Shakti Singh, regional officer, HSPCB, said, “We have collected samples and will comment once we get the reports after the lockdown is relaxed. The pollution in Najafgarh drain has reduced, but we cannot link it to the closure of industries without getting a sample report. We are aware of the GMDA’s assessment.”