Kolkata's sewer rehabilitation: benchmarking sustainable urban regeneration

Abstract

Rehabilitation of century-old brick sewers involves important sustainability and serviceability issues. The Kolkata Municipal Corporation initiated an ambitious project in 2007 to rehabilitate, in its oldest section, major brick sewers more than 130 years old. The first phase of this project involved refurbishment of three trunk sewers about 12 km long, forming the backbone of the core city area's ageing sanitation infrastructure. The long-term issues addressed included retention of discharge capacities of sewers, regaining their structural integrity, reduction in water logging, protection against corrosion, future cleaning and maintenance, and socio-environmental aspects. Adoption of trenchless technology helped significantly in execution of works in a heavily congested urban area. The project presented a perfect example of municipal asset management and sustainable urban renewal for a colonial city that has been in existence for over 300 years. The cost of the project was about £32 million and the refurbished sewers were recommissioned in 2011.