International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 09 | Sep 2025
p-ISSN: 2395-0072
www.irjet.net
Quantitative Assessment of Sewage Treatment Reforms on River Yamuna’s Ecological Restoration in Delhi Siddharth Upadhyay1 1 Junior Environmental Engineer, Delhi Pollution Control Committee, GNCTD, DELHI
---------------------------------------------------------------------***--------------------------------------------------------------------repeatedly recommended, particularly for controlling Abstract - Urban river pollution poses a significant
ammonia and fostering ecological function. Up-to-date DPCC monitoring reports, as attached, provide granular insights into monthly progress and challenges.
challenge for Delhi, with the Yamuna River suffering from acute water quality deterioration due to sources such as untreated municipal wastewater, industrial effluents, and upstream inflows. This study examines how increased sewage treatment capacity in Delhi impacts the Yamuna’s water quality, with a particular emphasis on metrics like biochemical oxygen demand (BOD), ammonia (NH₃-N), and broader pollutant load trends. The research reviews the expansion of treatment infrastructure, assesses water quality at critical monitoring points along the river, and measures improvements while recognizing persisting system constraints. Insights from this analysis support river restoration strategies and the development of effective urban water management policies for a sustainable revival of the Yamuna in Delhi.
3. MATERIALS AND METHODS I.
a) Total sewage generated: 792 MGD (July 2025) b) Installed STP capacity: 784 MGD (37 STPs at 21 locations) c) Effective treatment capacity: 667.93 MGD (85.2% utilization) d) Targets: Achieve 1011 MGD total by December 2027
Key Words: Yamuna River, Urban river pollution, Sewage treatment plants (STPs), Biochemical oxygen demand (BOD), Ammonia (NH₃-N), Water quality improvement, Pollutant load reduction
II.
b) Treatment Efficiency: The efficiency of an STP in reducing a pollutant concentration is:
The Yamuna River is the principal water body traversing Delhi, vital for ecology and urban sustainability, yet faces mounting pollution from rapid population growth and infrastructure gaps. As of July 2025, Delhi generates approximately 792 MGD of sewage, with installed STP capacity at 784 MGD and further upgrades targeted at achieving 1011 MGD by December 2027, aiming to meet the stringent DPCC standards (BOD/TSS: 10/10 mg/L). Despite capacity upgrades, effective treatment and consistent compliance remain hindered by operational issues and significant untreated pollution entering from upstream and local sources.
Where,
Previous studies emphasize that untreated sewage and industrial effluents are principal contributors to river pollution in Delhi. Work by CPCB, DPCC, and independent researchers such as Ghosh et al. (2019) and Tyagi et al. (2020) finds BOD and ammonia levels often exceed desired standards. Regulatory efforts focus on STP upgrades and enforcing compliance with more stringent effluent criteria. Integrated watershed and urban river management are
Impact Factor value: 8.315
Cin = Influent pollutant concentration
Cout = Treated effluent concentration
c) BOD Decay Model: The concentration of BOD at distance x downstream of pollutant source is modeled as:
2. Literature Review
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Water Quality Indicators and Formulas
a) Pollutant Load: L = Q x C, where Q is flow rate (MGD) and C is concentration (mg/L)[1]
1. INTRODUCTION
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Sewage Treatment System Data
Where,
C0 = initial BOD concentration at discharge point
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