New Delhi – A concerning report from the Delhi Pollution Control Committee reveals that 12 of Delhi sewage treatment plants failed to meet prescribed standards in November, highlighting a worsening crisis in the capital’s wastewater management infrastructure. The DPCC’s latest assessment, dated December 17, examined 37 facilities across the city and found widespread non-compliance with Central Pollution Control Board parameters. Additionally, samples could not be collected from a 13th facility at Sonia Vihar due to no flow during inspection, further complicating the assessment of Delhi sewage treatment plants performance.
Alarming Increase in Non-Compliance
The number of Delhi sewage treatment plants failing treatment norms has increased significantly, with nine such facilities identified in September and October reports compared to twelve in November. This upward trend indicates deteriorating performance across the capital’s wastewater treatment infrastructure. The monthly assessment reveals that a substantial section of Delhi sewage treatment plants do not meet prescribed norms for critical parameters including faecal coliform, biological oxygen demand, chemical oxygen demand, and total suspended solids.
Shocking Faecal Coliform Violations
The most alarming findings concern faecal coliform levels at several Delhi sewage treatment plants. At Molarband STP, faecal coliform levels reached 234 times the prescribed limit, representing a catastrophic failure in treatment standards. The Ghitorni treatment plant recorded levels 73 times higher than permissible limits, while Vasant Kunj-2 STP showed contamination 70 times above standards. These excessive levels pose serious public health risks, particularly as treated water from Delhi sewage treatment plants is discharged into the Yamuna River.
Against the prescribed limit of 230 MPN/100ml, specific Delhi sewage treatment plants recorded shocking readings: Molarband outlet showed 54,000 units, Mehrauli recorded 3,500 units, Vasant Kunj-2 measured 16,000 units, and Vasant Kunj-1 registered 9,200 units. These extreme violations underscore systemic failures in treatment processes across multiple facilities.
Facilities Failing Multiple Parameters
The DPCC report identified twelve Delhi sewage treatment plants that failed to meet standards: Sen Nursing Home STP, Delhi Gate, Kapashera, Molar Band, Okhla (old), Mehrauli, Vasant Kunj 1 and 2, Ghitorni, Yamuna Vihar Phase 1 and Phase 3, and Nilothi New (Phase-1). While most Delhi sewage treatment plants failed faecal coliform treatment levels, facilities at Mehrauli, Vasant Kunj, and Yamuna Vihar failed on three or more parameters simultaneously, indicating comprehensive treatment failures.
Total Suspended Solids Violations
Six Delhi sewage treatment plants failed to meet TSS and BOD standards, both of which should be less than 10mg/L according to CPCB parameters. TSS levels at outlets were three to four times higher than permissible limits: 36mg/L at Yamuna Vihar Phase-1, 27mg/L at Yamuna Vihar Phase-3, and 24mg/L at Vasant Kunj-2. These elevated suspended solid levels indicate inadequate filtration and treatment processes at these Delhi sewage treatment plants.
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Biochemical Oxygen Demand Failures
Biochemical oxygen demand levels—representing the amount of oxygen required by aquatic life to survive—were two to three times higher at several Delhi sewage treatment plants. The CPCB standard sets BOD levels at 10mg/L, but multiple facilities consistently exceeded this threshold. High BOD levels in treated water released into the Yamuna River severely impact aquatic ecosystems and contribute to the river’s ongoing pollution crisis.
Capacity and Infrastructure Challenges
Delhi sewage treatment plants face significant capacity constraints in addressing the city’s wastewater crisis. Delhi estimates sewage generation at 3,600 million liters per day or 792 million gallons per day, with approximately 80% of the water supply (990 MGD) returning as wastewater. However, the 37 Delhi sewage treatment plants at 20 locations have an installed capacity to treat only 667 MGD.
The Delhi Economic Survey highlights that actual capacity utilization of Delhi sewage treatment plants reaches only 565 MGD, creating a treatment gap of 227 MGD. This untreated sewage ends up in drains, water bodies, and the Yamuna River, exacerbating pollution problems. Even the 565 MGD that undergoes treatment suffers from underperforming facilities that fail to meet prescribed standards.
Groundwater Factor Ignored
Environmental experts point out that estimated sewage generation figures do not account for groundwater extraction by residents. Yamuna activist Bhim Singh Rawat, a member of the South Asia Network on Dams, Rivers and People, criticized this oversight. “The real quantum of sewage is much more, the STPs are inadequate and underperforming and even the water that gets treated does not meet norms,” he stated, emphasizing that Delhi sewage treatment plants face challenges beyond documented capacity constraints.
Systemic Accountability Failures
The recurring failures of Delhi sewage treatment plants highlight systemic accountability gaps in environmental governance. Rawat noted: “From years, we have been hearing about STPs not meeting norms but no accountability is fixed. There is no monitoring mechanism which involves civil society and violations continue every month without any repercussions.”
This absence of consequences enables persistent non-compliance, with Delhi sewage treatment plants repeatedly violating standards without facing meaningful penalties or corrective interventions.
Yamuna River Impact
The underperformance of Delhi sewage treatment plants directly impacts Yamuna cleanup efforts, as the river receives inadequately treated wastewater carrying excessive pollutants. Experts recommend that the government focus on improving STP management, restoring ecological flow, and protecting floodplains to address the Yamuna pollution crisis comprehensively.
The November report on Delhi sewage treatment plants underscores the urgent need for infrastructure upgrades, enhanced monitoring, stricter enforcement, and accountability mechanisms to protect public health and environmental quality in the national capital.
