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Ganga water fit to drink at many stretches: CPCB

Hindustan Times, New Delhi | ByJayashree Nandi
Apr 20, 2020 10:08 AM IST

This will change on Monday when several sectors start reopening gradually. Water quality experts said the lesson from the lockdown is to strictly ensure industries meet effluent discharge standards.

For the first time in many years, several stretches of the Ganga are conforming to Central Pollution Control Board’s (CPCB) standards for the quality of river waters, a phenomenon that follows the nationwide lockdown imposed on March 25 and extended until May 3. In fact, some stretches of the river are recording CPCB’s “fit for drinking water” norm with basic conventional treatment.

Experts say this is mainly owing to industries not discharging toxic effluents into the river and less withdrawal of water for industrial and agricultural purposes as part of the lockdown that has shut industrial activity and restricted agricultural work.

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This will change on Monday when several sectors start reopening gradually. Water quality experts said the lesson from the lockdown is to strictly ensure industries meet effluent discharge standards. More than 80% of the pollution in the Ganga is contributed by domestic sewage from surrounding towns and villages and the rest by industrial effluents, according to the National Mission for Clean Ganga.

CPCB’s assessment of Ganga water from January 2020 had shown that most stretches of the Ganga from Garhmukteshwar in Uttar Pradesh to West Bengal were not only violating drinking water standard but also recorded hardly any dissolved oxygen (how much oxygen is dissolved in the water) and extremely high levels of total coliform (bacteria from human and animal waste).

Many of the same stretches, according to CPCB’s real time water quality monitoring of the Ganga on Sunday, met the drinking water standards; the biological oxygen demand was < 3 mg/l, dissolved oxygen i >4 mg/l and ph 6 to 9. The biological oxygen demand is the oxygen needed by the river to sustain life.

“There are many reasons for improvement in water quality in Ganga. Industries is one of them.... Some distilleries have also stopped discharging. Waste dumping by people around the river also contributes to higher BOD {biological oxygen demand} which may have stopped as people are in lockdown. Its difficult to identify any one factor,” said a senior CPCB official who declined to be identified.

CPCB will soon release its analysis of Ganga and Yamuna water quality during the lockdown period from March 25. “Yes its true that we found dramatic improvement in water quality in many parts of the river but in some stretches we found that water quality has deteriorated after the lockdown was imposed. The reasons for this will have to be verified,” the senior official cited above added.

Experts urge policy makers to learn from the lockdown experience as access to clean water is also a public health issue and can play a critical role in tackling outbreaks like that of Covid-19.

“Industrial pollution is zero today. It is a major polluting factor for Ganga as it compromises the river’s capacity for assimilation. When sewage is mixed with industrial effluents, it is difficult for the river to assimilate the pollution. There is another reason for improvement and better dilution of pollutants. There were a very high number of western disturbances which brought rain and improved the flow in the river leading to better dilution. There are two key takeaways from this—industries have to become zero liquid discharge and environmental flow is a must in the river,” said Manoj Mishra, convenor of the Yamuna Jiye Abhiyan, descriptor.

E-flow refers to quality, quantity and timing of water flows required to maintain life in the river.

“Improvement in Ganga water pollution is a function of both quality and quantity. Water is not being lifted by industries so there is more flow in the river and the pollution is getting diluted. At the same time effluents are also not being discharged. It’s a same thing as you dilute something in a glass of water versus a bucket of water. Because of the harvesting season the agriculture sector also isn’t withdrawing much water now. If you leave nature on its own, it survives and comes back to life. This is a clear example but levels will go back up as soon as we reopen,” said Suresh Rohilla, senior director, water and waste water management, Centre for Science and Environment.

Stretches that met “drinking water quality” standard on Sunday

Stretches with biological oxygen demand (oxygen needed by the river to sustain life) is <3 mg/l, dissolved oxygen is>4 mg/l and PH is 6 to 9

• Kannauj, bathing ghat and barrage in Kanpur, Fatehpur bridge, Narora, Varanasi bathing ghat 1, Sukartal Ghat, Bhitpur, and Ganga nullah, Murshidabad and Howrah Bridge in West Bengal

Stretches with high pollution level on Sunday:

• Allahabad nullah with BOD of 15.35 mg/l and DO of 1.04 mg/l

• Haridwar nullah with BOD of 43.20 mg/l and DO of only 0.01 mg/l

• Nullah at Patna with BOD of 30.13 mg/l and DO of 0.25 mg/l

Source: CPCB

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