At fault for a frothy Yamuna: Raw sewage, frothing agents
Poisoned by tonnes of sewage, industrial and domestic effluents, the Yamuna in Delhi is frothing -- one of the signs of the exceptionally high levels of pollution in the river.
As Chhath Puja devotees took a dip in the river on Monday, iceberg like foam blocks were spotted floating on the river near Okhla Barrage, where the Yamuna leaves Delhi. The foam, experts said, is an annual phenomenon during winters, and is a clear symptom that indicates that the river stretch is “dead”.
According to a report by a monitoring committee appointed by the National Green Tribunal in 2018, the 22-km stretch of the Yamuna between Wazirabad and Okhla, accounts for 76% of the total pollution in the river.
River watchers and experts pointed out that the froth downstream of Okhla barrage has been occurring for more than a decade now but the magnitude of the problem has worsened in the last few years.
Manoj Misra of Yamuna Jiye Abhiyan said the froth formation starts immediately after the monsoon, and as temperatures drop during November, the magnitude of the problem increases. “The froth formation is a clear symptom that the river in this stretch is dead,” he said.
On Monday, Delhi Jal Board vice chairman Raghav Chadha said the neighbouring states have done little to prevent untreated sewage and industrial effluents from flowing into the river. Chadha said the Delhi Jal Board is working to enhance its sewage treatment capacity so that untreated effluents are not released into the Yamuna.
“Okhla Barrage is managed by the UP Irrigation department and water hyacinth plants grow all around. These hyacinth plants decompose and release surfactants like phosphates. The paper and sugar industries operating in Meerut, Muzaffarnagar, Shamli and Saharanpur in Uttar Pradesh also release untreated wastewater containing surfactants, which is then released into Yamuna through the Hindon Canal near Indira Kunj,” he said.
According to DJB estimates, the untreated discharge reaching the Okhla Barrage was 105 MGD (million gallons per day) from Haryana through Najafgarh drain, and 50 MGD from UP through Shahdara drain.
When asked, a senior jal board official explained that froth is formed due to soap-like surfactant molecules. He added that when the water falls from a height in the Okhla barrage, it leads to churning of the polluted water, and amplifies formation of foam.
“There are biological and chemicals reasons behind presence surfactant molecules in the river water. It can be due to detergents and surfactants in untreated domestic sewage, pollutants from industries as well as materials released by decomposition of dying water hyacinth weeds in the Okhla barrage,” the official said, asking not to be named.
Similar toxic froth floating on lakes has been observed in the past in Bengaluru and Hyderabad.
Last year, the NGT-appointed Yamuna monitoring committee took cognizance of froth formation in the Yamuna. Delhi Pollution Control Committee DPCC, in its report to the panel, blamed the presence of dhobi ghats, direct release of sewage containing phosphate and industrial effluents for the froth formation.
A senior DPCC official, asking not to be named, said phosphates from detergents and soaps that are directly released into the river untreated results in the formation of foam. “To control this, the DPCC in June this year, banned the sale, storage, transportation and marketing of soaps and detergents in Delhi, which did not meet the Bureau of Indian Standards (BIS) norms. This was done to prevent frothing in the river. Directions were issued to the civic supplies department and surprise checks are also being conducted around the city for the same,” the official said.
The official added that action was being taken against illegal industrial units operating along the Yamuna in areas such as Khayala, Bawana, Narela and Badli.
Varun Gulati, an activist who filed a petition in the NGT against illegal industries, said most of these units were operating without any common-effluent treatment plants, or without licence.
Misra said the high pollutant load shows how the city has failed the river. “We have seen that the river was much cleaner during the lockdown period when the household sewage was still getting added to river stream. If we can restore the river flow, as it happens during the monsoon season, and reduce the industrial pollutants, the river can be revived in this stretch,” he added.
A senior DJB official said that under the short-term remedial measures, all water hyacinth plants in the Okhla pond area will be removed, and as an immediate measure bio-culture based foaming treatment may be carried out.
“As a long-term measure, upgradation of all STPs by the UP, Haryana and Delhi is necessary to treat the waste water to substantially reduce the problem of foaming,” the official said, adding that it may take 3-5 years depending upon the availability of funds.
Jyoti Sharma, head of FORCE -- a Delhi-based water conservation and sanitation organisation -- said Delhi has enough environmental regulations and laws but citizen participation must be ensured to improve water quality in the river. “We should have citizen vigilance groups who can help in monitoring of STPs, industrial area and slum cluster outfalls. Unless, we develop a participative oversight mechanism, such alarming sights will continue to be present,” she added.
Health experts have warned that Chhath devotees should avoid this polluted section of river. According to Dr Rommel Tickoo, director, internal medicine at Max Saket, the froth caused by sewage and chemical pollutants can lead to gastrointestinal problems and water-borne disease such as typhoid.
He added, “Skin can absorb pollutants which can lead to allergies and skin irritation, but long-term exposure to metals in industrial wastewater can cause neurological issues, hormonal imbalance and it can also be carcinogenic.”