New Delhi: Nineteen out of 37 sewage treatment plants do not meet standards, according to Delhi Pollution Control Board's (DPCC) report for Oct.
The report, dated Nov 5, said that the DJB's STPs are not adhering to norms, mostly concerning faecal coliform, which indicates the presence of raw sewage and excreta in the water.
Apart from faecal coliform, many STPs failed to meet the standards for biochemical oxygen demand and total suspended solids.
While the standards for STPs compel them to have a faecal coliform level of 230 MPN/100ml (or most probable number for a 100 ml) with the desirable level being 100 units, the outlet at most of the STPs showed values ranging from 2,500 units at the Yamuna pillar, 2,200 units at Keshopur STP, 2,300 units at Okhla STP, 1,600 units at Nilothi, 1,800 units at Rohini, 1,400 units at Yamuna Vihar, and 1,200 units at the Coronation Pillar, to name a few.
Earlier this month, DJB submitted a report to National Green Tribunal (NGT) regarding the functioning of STPs after the tribunal took suo motu cognisance of a TOI report titled "Why 75% of Delhi's STPs aren't ready to tackle Yamuna stink" dated Feb 19.
In its report, DJB, while omitting details on faecal coliform, stated that it operated 38 STPs with an installed capacity of 792 MGD, of which it caters to 699.2 MGD. It is currently constructing some new and upgrading some old STPs, which will take its treatment capacity to 751.4 MGD by March 2025.
However, in its report, it stated that 19 STPs, which have a treatment capacity of 375.4 MGD, are working on the standards for BOD and TSS only.
The TOI had earlier reported that due to the absence of bacterial disinfection through either chlorination, UV treatment, or ozonation, despite a previous NGT order, the STPs couldn't manage the faecal coliform.
Thus, the sewage, post-treatment, was released further into the river, keeping it polluted and stinky.
A DJB report on the bacteriological analysis in Jan showed that faecal coliform levels at the outlet of one such major STP throughout Jan 2024 were 1,400,000,000 (one hundred and forty crores) MPN/100ml, while at another it was 24,000,000,000,000 (twenty-four thousand crores) MPN/100ml, and 4,600,000,000 (four hundred and sixty crores) MPN/100ml (most probable numbers per 100 ml of water) at a third STP.
There were then 28 such STPs with exponentially high faecal levels. Officials at STPs, however, stated that at present, 18 STPs have working disinfection facilities either through chlorination or UV treatment, while nine STPs are under construction with UV treatment facilities, and the process of installing UV devices at others is in the pipeline.