How clean is River Ganga? Here's a fact check

Around 97 towns and cities located on the banks of Ganga discharge over 3.2 billion litres of untreated sewage into the river daily. To keep the water from getting polluted, the National Mission for Clean Ganga (NMCG) took up a big challenge to clean and rejuvenate the holy river through the launch of several projects.

Among the new sewage treatment plants set up by NMCG is Salori STP near Bakshi Bandh in Prayagraj. The 14 MLD sewage treatment plant funded by NMCG was launched in 2016 at a total cost of Rs 24.25 crore and uses modern SBR (Sequencing Batch Reactor) technology to treat the water and make it suitable for discharge back into the river Ganga.

"We have been treating this water to less than 10 BOD (Biochemical Oxygen Demand). Such a treatment is not available with other technologies. Less than 10 BOD means a good treatment, which can be visible by comparing raw sewage and the treated one," said Durgesh Kumar, Assistant Project Engineer, Salori STP.

Chemicals and bacteria in the water are treated separately. "We chlorinate the treated water i.e., 4-5 PPM (Parts Per Million) or milligrams per litre. It kills all bacteria in the treated water," Kumar said.

For a reality check, scientists from Uttar Pradesh Pollution Control Board took samples from Triveni Sangam, the confluence of thee rivers, in Prayagraj. They regularly take water samples from various spots in the river to check the availability of Biochemical Oxygen Demand (BOD) in the water.

A laboratory analysis of the samples found that water quality tremendously improved with growing public awareness and steps taken by the NMCG.

"We observe the pollution level through Dissolve Oxygen Parameter which is also called Biochemical Oxygen Demand (BOD). The present dissolved oxygen in the river is around 8 to 9 BOD. It should be over 5 BOD and at present it remains at 8 to 9, which is quite satisfactory," said Ramjas Prasad, Monitoring Assistant, Uttar Pradesh Pollution Control Board, Prayagraj.

Several projects launched by the National Mission for Clean Ganga are about to fructify, which will help to completely stop the flow of untreated waste into river Ganga. However, public awareness will contribute largely to make the river clean.

"Even with all these investments we are able to clean it very quickly, like in two-three years, keeping it clean is equally a big challenge. We all clean our houses. Even if you leave it once after a month you will find your home very dirty. Same is the case with city, same is the case with a village, and same is the case with a river," said Rajiv Ranjan Mishra, Director General, National Mission for Clean Ganga.