Pune: The civic body’s environment status report for 2023 indicated that Mutha river was extremely polluted, much more than Mula-Mutha. The environment status report (ESR) is based on sample analysis of water from the rivers in the city. It said the biochemical oxygen demand (BOD) and chemical oxygen demand (COD) in the Mutha exceeded the Central Pollution Control Board’s (CPCB) standards.
The CPCB BOD standard is 30mg/l and COD standard is 150mg/l. The Pune Municipal Corporation (PMC) collected samples from six locations across the river, finding the stretch near Mhatre Bridge highly contaminated. BOD is the amount of oxygen consumed by bacteria or microorganisms as they break down the organic matter (like sewage content) present in the water, thus decreasing the level of oxygen and leading to production of various compounds, some harmful.
It also leads to death of aquatic life and presence of water hyacinth. COD is the amount of oxygen needed to dissolve the chemical organic matter (industrial effluents). In all, the ESR studied six locations in Mutha river, eight in Mula-Mutha river, indicators in Pavana and Katraj Lake as well as Ambil, Nagzari and Bhairoba nullahs.
Out of all the locations, the Mutha river showed the highest level of contamination. PMC environment officer Mangesh Dighe told TOI, “Mutha river is very clean before it enters the city limits. However, the many nullahs carrying untreated sewage into the river within city limits contaminate Mutha.
The JICA project is addressing the sewage problem. The contamination levels are only a little above permissible limits and all the parameters are well within the limit for Mula-Mutha river.” According to the ESR, currently, 477 MLD of sewage is being treated in the city’s sewage treatment plants (STP) with a capacity of 576 MLD.
Meanwhile, 11 more STPs with a capacity of 396 MLD have been approved by the Centre to control pollution of Mula-Mutha river. PMC officials said the work to connect and lay large diameter drains has been started to ensure open sewage flowing to the river and canal in PMC areas is directed to the nearest STP. Similarly, the BOD concentration in Pashan lake was higher than the standard directed by the CPCB at 33.
25 mg/l in 2023, an increase from 24.56mg/l in 2022. In the Mula-Mutha river, both COD and BOD levels were found to be within permissible limits of CPCB.
Shailaja Deshpande, founder of NGO Jeevitnadi, told TOI, “Mutha does not have any natural bank system or groundwater springs to dilute the pollution. Mula-Mutha’s stretches in the city are greener and have some groundwater springs. The pollution is exceeding all norms in Mutha river because of high BOD.
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