Post By: Dr. Ravi Chopra
The Government had claimed last year in 2018 that water of Ganga had become cleaner than the past. In May 2018 Water Resources Secretary U P Singh “asserted that water quality of the river has improved in terms of three key parameters – Biochemical Oxygen Demand (BOD), Dissolved Oxygen (DO) and Coliforms… Water quality at 80 locations showed improvement in 2017 as compared to 2016. The DO levels have improved at 33 locations and BOD levels at 26 locations while Coliform bacteria count is reduced at 30 locations.” These claims were allegedly made on the basis of a Central Pollution Control Board report for the 2015-17.See Report Here.
In June 2018 a news report claimed that “water quality trend on tributaries of Ramganga river viz., Bahela, Dahela, Kosi and Ramganga itself before its confluence with Ganga has shown improvements during the last two years.” See Report Here. These claims are made on the basis of measurement of physico-chemical parameters like pH, DO (Dissolved Oxygen), BOD (Biological Oxygen Demand), TSS (Total Suspended Solids), etc.
However, another report by Central Pollution Control Board (CPCB) released in June 2018 questions these same claims. See Report Here. This report is based on a bio-monitoring methodology which reveals the impact of continuing pollution over a longer stretch of the river.
Physico-chemical monitoring informs us of the water quality at a particular location, at a particular time. Selected parameters – based on desired objectives, e.g. testing for drinking or for bathing purposes, etc. — are measured by collecting river water samples at different locations and performing chemical tests or physical measurements, generally in a lab. They give the values of the water quality parameters only of the samples gathered. Altering the location slightly or the time of sampling can lead to different water quality results. For example, a water sample taken near the bank of a river and one taken in the middle can give very different results.
Bio-monitoring involves gathering specimens of micro-organisms that live on the bed of the river or underneath rocks on the river bed. It informs us of the impact of pollution (or the water quality) on the lives of the river’s biota. Some species are sensitive to pollution while others can be pollution tolerant. The types of organisms gathered and their numbers are recorded. A scoring method is used to determine the pollution level or the water quality. For example, absence of pollution-sensitive organisms indicates higher pollution levels over time.
The later Bio Monitoring Report says that upstream of Bhimgoda the BWQ (Biological Water Quality) of Ganga improved from class B (slight pollution) in 2014 to class A (clean) in 2017. However, in the next few kilometers, with a couple of sewage drainsreleasing directly into the river, its water quality deteriorated.
Just downstream of Haridwar and upstream of the Jagjeetpur Sewage Treatment Plant (STP), the BWQ degraded from class A in the 2015 d to class C (moderate pollution) in 2017. Downstream of the Jagjeetpur STP the deterioration was sharper – from class A in 2014 to class D (heavy pollution) in 2017. These data show that the claims of improvement made by the Government do not hold. Actually the water quality has deteriorated.
There is a close connection between the amount of water and the level of pollution. More water flow not only directly dilutes the pollution but the reduced level of pollution enables aquatic live like fishes to survive and they clean up the pollution further. The increase in the level of pollution downstream of Bhimgoda indicates that the discharge from the Bhimgoda barrage, which diverts water into the Upper Ganga Canal, is inadequate to absorb the pollution load entering the river from the city and needs to be increased.
Typically the BOD of an STP’s effluents must not exceed 30 milligrams per liter (mg/l) while the river water quality for bathing demands a BOD value of 3mg/l or less. Therefore the river discharge should be at least 10 times that of the STP discharge. Obviously the river discharge downstream of the barrage is inadequate to dilute the effluents emerging from the Jagjeetpur STP and therefore the BWQ deteriorates from class C (u/s of Jagjeetpur) to class D (d/s of Jagjeetpur).
The fact is that it is difficult to ensure flow of 10 times the treated water released from the Jagjeetpur STP because of the demands from irrigation. A solution would be that the treated effluent from Jagjeetpur be diverted elsewhere, say for irrigation purposes back into the Upper Ganga Canal. This will provide double benefits. The river water downstream of Jagjeetpur will not be polluted by the addition of treated effluent with 30 mg/l BOD. Secondly, more water can be released from Bhimgoda and that will revive the Ganga River.
