Rehabilitation & Upgradation — Kondli 45 MGD STP
IFAS retrofit case study to meet CPCB/DPCC norms — Euroteck Euroclean IFAS
Overview
This case study describes rehabilitation & upgradation of an existing 45 MGD (204.3 MLD) Kondli sewage treatment plant (commissioned 2013) using Euroteck's IFAS (Integrated Fixed Film Activated Sludge) technology. Source file: :contentReference[oaicite:1]{index=1}
Background
The Kondli STP (45 MGD) was originally based on conventional Activated Sludge Process (ASP). With stricter discharge norms from CPCB/DPCC, the plant required upgrades for nutrient removal (N & P), improved BOD/TSS removal, coliform removal and improved sludge handling — all within the existing footprint.
| Parameter | Influent | Treated (Norm) |
|---|---|---|
| Flow | 45 MGD | 45 MGD |
| pH | 6 - 8.5 | 6.5 - 9.0 |
| BOD5 (mg/L) | ~250 | ≤10 |
| COD (mg/L) | ~500 | ≤50 |
| TSS (mg/L) | ~450 | ≤10 |
| Coliform (MPN/100ml) | 1.2 × 106 | 100 |
| NH₄-N (mg/L) | ~36 | ≤5 |
| TP as P (mg/L) | ~8 | ≤1 |
Observed Challenges
- No provision for biological nitrogen & phosphorus removal
- No spare land for new tanks or civil structures
- Inefficient TSS removal and sludge management
- Inadequate aeration for nitrification & high DO demand
- Need for quick execution without stopping plant operation
Solution: Euroclean IFAS Aâ‚‚O Retrofit
The chosen solution retrofitted Euroclean IFAS media modules into existing aeration tanks mounted on stainless frames, added dedicated anaerobic/anoxic zones, upgraded aeration, introduced DO & NHâ‚„ sensors with OCEMS, improved clarifiers and implemented tertiary filtration and energy-efficient sludge dewatering.
- No additional land required — retrofit within existing footprint
- Quick installation with minimal disruption
- Improved nitrification, phosphorus removal & TSS reduction
- Reduced excess sludge, improved biogas generation
- Lower capex vs building new tanks; faster construction time
Design Approach
Existing system used four parallel aeration tanks (conventional fine-bubble) with MLSS ≈ 3,000 mg/L. Retrofit raised equivalent MLSS to 5,000–8,000 mg/L and upgraded aeration to meet increased oxygen demand for effective nitrification.
- IFAS modules fitted into existing tanks
- Dedicated anaerobic/anoxic zones created (no demolition)
- Advanced tertiary filtration for <10 ppm TSS
- DO and NHâ‚„ sensors for real-time control
Performance Results
BOD5 removal
>98%
NHâ‚„-N removal
>98%
TP removal
>80%
| Parameter | Before Retrofit | After Retrofit |
|---|---|---|
| Flow treated (m³/day) | 204,570 | 204,570 |
| BOD5 removal (%) | ~80% | >98% |
| NHâ‚„-N removal (%) | ~40% | >98% |
| TP removal | <40% | >80% |
| Effluent BOD5 (mg/L) | 30–50 | <10 |
| Effluent NHâ‚„-N (mg/L) | >15 | <5 |
| SVI | 180 | 120 |
Cost & schedule highlights: Retrofit capital cost ≈ 45% of a new tank construction; construction time reduced from 12–18 months (new) to ~4–6 months (retrofit); payback < 3 years via avoided civil works and operational efficiency.
Conclusion & ESG Impact
Retrofit with Euroclean IFAS increased effective treatment capacity, improved effluent quality to meet regulatory standards, and extended the life of existing infrastructure. Environmental and social benefits include lower carbon footprint, improved community health, enhanced governance/compliance, and potential carbon/ESG credits.