sewerage

Sewerage refers to the physical network and associated processes for the collection, conveyance, treatment, and disposal or reuse of wastewater and stormwater. It is designed to remove used water and prevent pollution, protect public health, and support urban sanitation. A sewerage system typically consists of an interconnected network of pipes (sewers), manholes, and pumping stations that transport wastewater by gravity or pumps to treatment facilities. Separate systems carry sanitary sewage and stormwater in different pipes; combined systems carry both, which can overflow during heavy rainfall.

Wastewater from households, industry, and institutions enters the sewer network, where infiltration and inflow are common problems that add extraneous water. Treatment plants perform a series of processes, including primary sedimentation to remove solids, secondary biological treatment to degrade organic matter, and sometimes tertiary treatment for nutrient removal or disinfection. Sludge produced is treated and disposed or reused as biosolids.

Discharge of treated effluent and disposal of solids are regulated by environmental authorities through standards and permits. In many regions, treated wastewater is reused for irrigation or industrial processes, and biosolids are applied to land or disposed of.

Maintenance of pipes and pumps, reduction of odors and blockages, and resilience against floods are important operational considerations. History shows sewerage as a cornerstone of modern public health, reducing waterborne diseases. Global practice varies with urban density, resources, and governance, but the goals remain the same: protect water bodies, safeguard health, and enable sustainable urban living.