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Chattogram Metropolitan Sewerage: Chattogram Sewage Infrastructure Analysis

Overview of the Chattogram Metropolitan Sewerage Project

Chattogram (Chattogram), with a population of around 5 million, is Bangladesh's second-largest city and largest seaport, yet it still lacks a centralized sewerage system. As a result, untreated municipal wastewater is discharged into the Karnaphuli River. The Metropolitan Sewerage project led by Chattogram WASA (Water Supply and Sewerage Authority) is a major environmental infrastructure program designed to collect and treat wastewater across the city through wastewater treatment plant (STP) construction, sewer network rehabilitation, and pump station installation.

5M
Targeted Population
Chattogram Metro Area
USD 1.2B
Total Project Cost
Approx. Tk 144B
400,000m³/day
STP Capacity
200,000m³/day in Phase 1
350km
Sewer Network
Trunk + Branch lines
ADB + AIIB
Financing
Joint loans
7 years
Construction Period
2025-2032

Construction Package Structure

Key Packages of the Chattogram Sewerage Project
PackageScopeScaleCostFunding Source
STP-1Phase 1 wastewater treatment plant200,000m³/dayUSD 400MADB
SN-1Trunk sewer network120kmUSD 300MADB
SN-2Branch sewer network230kmUSD 250MAIIB
PSPump stations (12 sites)Lift infrastructureUSD 100MADB
EMElectrical, instrumentation, SCADAFull facilityUSD 80MAIIB
PMCProject management consultingFull facilityUSD 70MADB

Treatment Process and Technology Comparison

STP Treatment Technology
Primary ProcessA²O (Anaerobic, Anoxic, Oxic)
Discharge QualityBOD < 10, TN < 10, TP < 1
Sludge ProcessingAnaerobic digestion + dewatering
Energy StrategyParallel biogas power generation
Sewer Network System
Trunk ConduitsRC pipes Φ800–2,000mm
Branch ConduitsPVC/HDPE pipes Φ200–600mm
Construction MethodOpen excavation + micro-tunneling (urban)
ManholesApproximately 8,000
01
Current Sanitation Conditions in Chattogram
Chattogram does not yet have a centralized sewerage system and still relies on septic tanks and natural drainage channels (Khals). Approximately 600,000m³/day of wastewater generated by the 5-million population is effectively discharged untreated into the Karnaphuli River, causing severe water-quality pollution (BOD 80-120 mg/L) and public health concerns. WHO and ADB have identified sewerage development in Chattogram as a top environmental priority.
02
Joint ADB-AIIB Funding Structure
ADB contributes USD 770M across STP-1, SN-1, PS, and PMC, while AIIB provides USD 330M for SN-2 and EM. The Government of Bangladesh will contribute USD 100M as counterpart funding. Both ADB and AIIB packages are procured through international competitive bidding (ICB), creating open participation opportunities for Korean firms. The STP package (around USD 400M) is likely to be implemented under a design-build-operate (DBO) model.
03
Export Opportunities for Korean Companies
(1) STP design and construction: Korean environmental engineering firms such as Global E&C Korea, Korea Engineering Co, and 코리아GS Construction are expected to be competitive in A²O-based plant works. (2) Pipe materials: Supply of HDPE, PVC, and RC pipes. (3) Pumps and valves: Water pumps and gate valves from Korean pump manufacturers. (4) SCADA and instrumentation: Sewerage monitoring and supervisory systems. (5) O&M consulting: Operational handover and maintenance technology transfer for treatment plant operation.
04
Key Risks and Mitigations
(1) Urban network installation: Heavy traffic and buried utility conflicts can slow construction, so pipe-jacking methods should be prioritized. (2) Monsoon flooding: Construction interruptions and flooding from June to September require stronger dewatering and schedule control. (3) Land acquisition: STP land requirement of about 30 hectares; Patenga industrial zone remains a likely candidate location. (4) O&M funding: Estimated annual O&M expenditure is around USD 15M, requiring a sewer tariff framework for sustainable operations.

Implementation Timeline

2023
ADB Feasibility Study completed
↓
2024
ADB and AIIB loan approvals obtained
↓
2025
Tendering for STP-1 and SN-1
↓
2026-28
STP and sewer network construction
↓
2029-30
SN-2 and pump stations completed
↓
2031-32
Commissioning and commercial operation
Gas Pipeline ProjectEnergy infrastructure pipeline development
Coastal Embankment Improvement Phase-IICoastal infrastructure protection works

The Chattogram Metropolitan Sewerage project is one of Bangladesh's largest environmental infrastructure programs at about USD 1.2B. By building a 200,000m³/day treatment facility in phase one and 350km of sewer lines, it will address wastewater challenges affecting 5 million residents. Korean firms can leverage strengths in STP design-construction (DBO), sewer materials, and SCADA, while active pre-qualification is essential as ADB and AIIB joint ICB bidding is in progress.

seweragewastewater treatmentChattogramurban infrastructureenvironmental engineering
Chattogram Metropolitan Sewerage: Chattogram Sewage Infrastructure Analysis | Dhaka Trade Portal