New Delhi: In a bid to tackle the persistent pollution in the Yamuna River, Delhi is set to introduce ultraviolet (UV) treatment at several sewage treatment plants (STPs). This initiative aims to control faecal coliform levels, a primary indicator of pollution. Currently, only the STP at Kapashera employs UV technology, although water is treated for faecal coliform at 15 other STPs.
Sources indicate that over 75% of the city’s STPs have been unsuccessful in reducing faecal coliform levels to acceptable standards. The primary reason for this shortfall is the lack of adequate bacterial disinfection technologies, such as chlorination, UV treatment, or ozonation. This deficiency persists despite the National Green Tribunal (NGT) mandate for such technologies.
Recent bacteriological analysis reports have highlighted the severity of the issue. For instance, faecal coliform levels at the outlet of one STP in January reached 1.4 trillion MPN/100ml (most probable number per 100ml of water). Another STP recorded levels as high as 24 trillion MPN/100ml, while a third reported 4.6 trillion MPN/100ml. A Delhi Jal Board (DJB) official noted, “DJB has 38 STPs, of which 15 are now complying with the latest NGT norms, including faecal coliform levels. The standard requires faecal coliform to be below 230 MPN/100ml, and we have managed to reduce it below 100 MPN/100ml at some STPs, which is the desirable norm.” DJB officials have set an ambitious goal to upgrade 28 out of the 39 STPs by September. These upgrades will align the STPs with NGT standards, particularly in reducing faecal coliform levels to below 230 units. Of the 15 compliant STPs, only Kapashera uses UV treatment, while others rely on chlorination and other methods. Currently, nine STPs are undergoing augmentation, and four are in the trial phase.
The ageing infrastructure of many STPs necessitates these upgrades to meet current standards. “Many of Delhi’s STPs are very old and need to be upgraded. Initially, these facilities did not consider faecal parameters until the NGT introduced the norms. Now, they are being upgraded,” the DJB official explained. Furthermore, the Yamuna Vihar Phase-2 STP is being upgraded to increase its capacity from 10 million gallons per day (MGD) to 15 MGD. Similar upgrades are underway at Kondli and Rithala Phases I and II.
The introduction of UV technology in all new STPs is expected to significantly enhance the quality of water discharged into the Yamuna. The DJB official expressed optimism, stating, “We hope that once these STP facilities are commissioned, the river’s water quality will improve. Decentralised STPs will also play a crucial role in treating effluents from unauthorised areas. This will prevent overloading at centralised STPs and ensure untreated sewage does not flow into the Yamuna through stormwater drains.” The concerted efforts to upgrade Delhi’s STPs and incorporate advanced technologies are pivotal in the ongoing endeavour to revitalise the Yamuna River, aiming to transform it from a polluted waterway to a cleaner, healthier river.
