New Delhi, Sep 21 (PTI) The Yamuna river recorded an improvement in water quality in August, with faecal coliform levels declining sharply from the previous month, even as Biological Oxygen Demand (BOD) levels remained high, according to the latest data from the DPCC.
The reduction in faecal coliform levels indicates a possible decline in untreated sewage entering the river, although monsoon rainfall during the period may have also contributed to the improvement. BOD levels, meanwhile, showed improvement compared to July, but remained elevated, the data showed.
The water quality testing by Delhi Pollution Control Committee (DPCC)involves collecting water samples from across seven locations along the course of the Yamuna river through Delhi, measuring
several parameters such as BOD, dissolved oxygen, chemical oxygen demand, pH and faecal coliform, to determine the pollution level.
The seven locations include major points like Palla, Wazirabad, ISBT Bridge, ITO Bridge, Nizamudin Bridge, Okhla Barrage and Yamuna river at Asgarpur (Kidwali, Haryana).
All six points showed considerable amount of improvement, in terms of faecal coliform levels for the month of August, according to the DPCC data.
However, five of the readings remained much higher than the permissible limit of 2,500 and the desirable level of 500.
The June report showed improvement at Nizamudin Bridge, as levels of faecal coliform went down to 13,000 Most Probable Number per 100 millilitres (MPN/100 ml), as compared to 130,000 MPN/100 ml in July.
The river showed improvement at Asgarpur, where levels of faecal coliform remained at 36,000 (MPN/100 ml) in August, an improvement from 320,000 in July.
The other locations which also showed improvement were Palla, where faecal coliform levels decreased to 1,400 MPN/100 ml in August from 2,100 MPN/100 ml in July; Wazirabad where the level went from 3,500 MPN/100 ml to 1,100 MPN/100 ml; and ITO bridge where the level improved from 120,000 MPN/100 ml in July to 17,000 MPN/100 ml in August.
Okhla Barrage recorded an improvement from110,000 MPN/100 ml to 23,000 MPN/100 ml in August; and ISBT Bridge, where the level improved from 170,000 MPN/100 ml to 35,000 MPN/100 ml in August.
BOD levels for August showed improvement but remained beyond the permissible limit at certain locations, ranging from 3-28 milligrams per litre (mg/l), while the water quality criteria stipulates a maximum of 3 mg/l.
The highest BOD was recorded at ISBT Bridge at 28 mg/l.
The DPCC has also uploaded the data for waste water quality at Delhi’s major drains for August, according to which several drains, discharging directly into the Yamuna, as well as supplementary drains of the Najafgarh canal showed high BOD and TSS (Total Suspended Solids) levels. PTI AHD PRK
