Overview of Delhi’s Sewage Treatment Challenges
The Delhi government claims that its sewage treatment plants (STPs) are functioning at over 88% capacity, implying efficient wastewater management. However, the Delhi Pollution Control Committee (DPCC) reports discrepancies in water quality from these plants.
Water Quality Deficiencies
- Out of 17 drains carrying treated effluent, 16 exceed permissible pollution levels.
- Key parameters breached include:
- pH
- Total Suspended Solids (TSS)
- Chemical Oxygen Demand (COD)
- Biological Oxygen Demand (BOD)
- High BOD levels threaten aquatic life by depleting dissolved oxygen.
Challenges in Drains and Treatment
- 22 drains feed the Yamuna within Delhi; 10 are fully tapped, and two partially.
- Eight drains remain untapped and require diversion to treatment facilities.
Pollution Causes and Treatment Shortfall
- The primary pollution cause is the discharge of treated, partially treated, and untreated sewage.
- Current treatment shortfall: 88 million gallons per day (MGD), primarily due to unauthorized colonies lacking sewer networks.
Measures to Address Shortfalls
- Upgrade and expansion of eight STPs at various execution stages.
- Development of 40 decentralised treatment units:
- 26 Decentralised Sewage Treatment Plants (DSTPs) across the city
- 14 in the Najafgarh drainage zone
Future Plans and Requirements
The Delhi Jal Board (DJB) has initiated a tender for a long-term Sewerage Improvement Scheme 2043, which includes:
- Surveys
- Detailed Project Reports (DPRs)
- Gap analysis
- A citywide sewerage master plan
Senior DJB officials emphasize the need for additional STPs to accommodate increasing sewage due to population growth and urban expansion.
