Management Of Wastewater And Stormwater

Wastewater and Stormwater Collection and Transfer

In many situations, gravity sewers follow the natural topography, and are used for collecting sanitary sewerage. The elements of a classical system are:

House Connections

Also referred to as building sewers, connect to building pumping systems. Generally, the house connection starts outside of the house. In many municipalities, septic tanks are taken out of service while a building is connected to the sewer.

Laterals

Laterals are the first municipal sewers serving a set of houses. They are commonly 150mm diameter minimum and situated in streets or special easements.

Main Sewers

Collect wastewater from various laterals.

Trunk Sewers

The largest elements, that delivers raw sewage to treatment facilities or disposal points.Collection of wastewater is by use of a sewerage system. Depending on the whether blackwater is produced separately from greywater, or mixed along with it, we require collecting greywater or the mixture of blackwater and greywater (sewage). Gravity is used wherever probable to convey the wastewater. The principle of using gravity as the driving force for conveying wastewater in a sewerage system should be applied wherever probable, since this will minimize the cost of pumping. Natural stormwater drainage happens in what is commonly termed a catchment basin. Within a catchment basin, rainwater run-off flows to a general point of discharge, and in doing so it creates rivers and streams.

Sewerage systems can be classified into combined sewerage and separate sewerage. Combined sewerage carries stormwater and wastewater both, although separate sewerage carries stormwater or wastewater separately. Recent trends have been for the development of separate sewerage systems. The major purpose for this is which stormwater is commonly less polluted than wastewater, and which treatment of combined wastewater and stormwater is hard during heavy rainfalls, resulting in untreated overflows. Conventionally sewerage pipes are laid deep beneath the ground. A minimum velocity is needed to ensure that self-cleansing conditions occur at least once daily. Pumping is generally required at various stages of the sewer pipe network, especially if the landscape is fairly flat.