Karanj STP: 211 MLD with BNR & 1.0 MWe Power

Advanced IFAS-SBR Upgrade for Capacity, Quality & Energy Recovery
Location

Karanj, Surat, Gujarat, India

Procedure

Augmentation, Technology Upgradation & New Module Addition (EPC/Turnkey)

Contract Type

Turnkey EPC with PMC Oversight

Capacity

211 MLD

Karanj STP: From 140 MLD to 211 MLD – High-Performance BNR & Renewable Power Integration

Completed in 2024 for Surat Municipal Corporation, this major upgrade transformed the Karanj Sewage Treatment Plant by enhancing the existing ~140 MLD capacity with IFAS technology and adding a new 71 MLD SBR module — achieving a total of 211 MLD. The project delivers Biological Nutrient Removal (BNR) for superior effluent quality (low BOD, TSS, nitrogen, and phosphorus), while incorporating 1.0 MWe biogas-based power generation from sludge digestion for on-site energy recovery and reduced grid dependency.

Executed within a minimized footprint through compact, high-rate processes, it minimizes civil modifications and supports Surat’s sustainable wastewater goals: compliant discharge, potential reuse, and circular economy benefits in one of India’s leading urban water management models.

Boosting Capacity, Achieving Nutrient Removal Excellence, and Energy Self-Reliance

Primary aims:

  • Augment treatment capacity by +71 MLD to meet rising East Zone sewage demands from urbanization and population growth.
  • Upgrade treatment quality with IFAS + SBR for effective BNR, targeting stringent parameters for environmental compliance and river health.
  • Minimize site footprint expansion by leveraging compact technologies and smart retrofits on existing infrastructure.
  • Integrate 1.0 MWe biogas power generation for renewable energy production, cost savings, and operational sustainability.
  • Strengthen Surat’s wastewater infrastructure as part of broader reuse/recycling initiatives.

Balancing Expansion, Quality Demands, and Space Constraints

Key obstacles included:

  • Limited available land — all upgrades and new 71 MLD SBR had to fit within or adjacent to the existing minimized footprint.
  • Retrofitting IFAS into operational plant without major disruptions to ongoing treatment.
  • Achieving consistent BNR performance (nutrient reduction) under variable municipal sewage loads and quality.
  • Ensuring reliable biogas yield for 1.0 MWe power amid fluctuating organics/sludge.
  • Coordinating phased works to maintain compliance and avoid downtime in an active facility.

Hybrid IFAS-SBR System with Energy-Positive Features

Deployed a hybrid approach: IFAS for enhanced biomass retention and nitrification in existing units, combined with a new high-efficiency SBR for flexible sequencing, denitrification, and final polishing to deliver robust BNR.

Core elements:

  • Compact IFAS media integration for higher loading rates and nutrient uptake in reduced space.
  • Dedicated SBR trains for optimized process control and superior effluent quality.
  • Advanced anaerobic digestion optimized for biogas production, powering a 1.0 MWe genset for captive use.
  • Automation (PLC-SCADA) and tertiary filtration (if incorporated) for reliability and minimal civil additions.

This solution maximized efficiency, minimized land/civil works, and achieved energy-positive operations aligned with national green standards.

Assessment & Planning

Detailed site evaluation, flow/load analysis, and feasibility study to map augmentation within existing footprint and set BNR/power targets.

Design & Technology Selection

Hybrid IFAS-SBR process engineering, biogas system design (1.0 MWe), and layout for minimal civil impact finalized.

Phased Implementation

Retrofit IFAS in existing units + construct new 71 MLD SBR, digesters, genset — executed with continuous operations maintained.

Commissioning & Optimization

Seeding, gradual ramp-up, BNR tuning, biogas-to-power integration, and performance adjustments to meet design metrics.

Testing, Validation & Handover

Rigorous trials confirming BNR efficacy, stable 1.0 MWe output, compliance, full SMC handover, and monitoring setup.
Stage One
Stage Two
Stage Three
Stage Four
Stage Five

Project Partners

Fostering high-impact collaborations to deliver resilient environmental infrastructure and localized engineering excellence.
Surat Municipal Corporation (SMC)
Enviro Control Pvt. Ltd.

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