West Bengal treats only 49 per cent of the waste water before dumping it in the Ganga, says a recent assessment report on the pollution in the river, prepared by the Central Pollution Control Board (CPCB).
The study raises concern about the inefficiency of sewage treatment plants (STPs) in West Bengal, which generates 1,311 million litres a day (mld) of waste water. While the 34 STPs in state have a total installed capacity of 457 mld, their actual utilisation is only 214 mld, which is only 49 per cent. Of 1,311 mld of waste water, 47 per cent is generated by Kolkata alone.
CPCB has identified 64 STPs in the Ganga river catchment (in Uttarakhand, Uttar Pradesh, Bihar, West Bengal), and inspected 51 of them. The total installed capacity of 51 STPs is 1,009 mld. But the actual utilization was found to be a meagre 602 mld, which is only 59 per cent. Nine STPs were found to be violating the biological oxygen demand (BOD, indicator of oxygen available in water) standard and exceeded the chemical oxygen demand (COD, measure of organic pollutants in water) standard. As many as 14 STPs were found non-operational.
The study observed that capacity utilisation of waste water in West Bengal needs immediate attention and all the non-functional STPs need to be made functional. The STP’s at New Bhatpara, Titagarh and Bandipur needs improvement. Uttar Pradesh, Jajmau, Dinapur, Bhagwanpur at BHU needs improvement in its performance. Bihar’s treatment plant at Chhapra needs to be made functional and STP at Lakkarghat in Uttrakhand needs improvement in its performance, says the report.
Pollution from drains
CPCB also made an inventory of the138 drains that flow in the Ganga river catchment. Total 76 per cent of the pollution load was contributed by Uttar Pradesh. Maximum flow of pollutants was also measured in Uttar Pradesh. In Uttar Pradesh, Chhoyia, Permiya and Sisamau nallahs are the major polluting drains, which contribute maximum to the river’s pollution load. The maximum number of point sources were identified in West Bengal. They number 54.
“This indicates that if the pollution load in the major drains of Uttar Pradesh, Bihar and West Bengal is tackled, water quality would show substantial improvement,” the assessment said.
The report found that BOD levels were under prescribed limits from the river’s origin at Gomukh to Rishikesh and in certain parts of Bihar. However, in the stretch of Rishikesh, downstream to Garhmukteshwar, and Kannauj upstream to Trighat and few locations in West Bengal (Dakshineshwar, Uluberia and Diamond Harbour), water quality exceeds the criteria and BOD is very high. The pH level is meeting the criteria at almost all the monitoring locations while faecal coliform is far in excess of the prescribed norm at most of the monitoring locations from Kanpur downstream up to Diamond Harbour.
CPCB surveyed and monitored river Kali (East) and Ramganga, tributaries of the Ganga from Uttarakhand to Uttar Pradesh, and made an inventory of point sources of pollution. It found that the flow of river Kali is non-existent at its source, Khatauli town, and it was seen flowing only during monsoon.
The report also prepared an inventory of the 764 grossly polluting industries (GPIs) discharging waste water into the main stem of the Ganga (either directly or through drains) and its two important tributaries Kali-east and Ramganga in Uttarakhand, Uttar Pradesh, Bihar and West Bengal.
It was observed that water consumed by grossly polluting industries is 1,123 mld. In terms of number of industrial units, the tannery sector dominated, whereas in terms of waste water generation, pulp and paper sector dominate, followed by chemical and sugar industries. It is also observed that GPIs in Bihar generate minimum wastewater (19 per cent) in terms of water consumed whereas GPIs in West Bengal generate maximum waste water, 75.5 per cent in terms of water consumed, followed by Uttarakhand (56.7 per cent) and Uttar Pradesh (39 per cent ).
In the riverine system, Ramganga carries maximum industrial waste water followed by main stream of river Ganga and Kali-east respectively.
J S Kamyotra, member secretary of CPCB, said that the report has been submitted to the Union Ministry of Environment and Forests for further action. It is up to the ministry now to prepare a roadmap to keep Ganga pollution free, he said.