Sanitary Sewerage Zone for Calcutta Metropolitan District

For the maintenance of health and sanitation of a community it is desirable to dispose of sewage i.e. waste-water in a sanitary manner. The primary object of sewage treatment is the protection of public health in addition to aesthetic, economical and recreational considerations and also to meet the demand for cleaner stream. In order to convey sewage from individual household to the sewage treatment plant it is essential to lay network of pipe lines with proper grade, size and slope. The reticulation system to carry the sewage or wastewater is called sewerage system and the individual pipe lines are called sewers.