Gravity Sewer Systems Explained

Giannetti Contracting

Giannetti Contracting
Image: giannetticontractingcorp.com

A multi-million dollar construction company based Pompano Beach, Florida, Giannetti Contracting provides underground utility installation services. The expertise of Giannetti Contracting in this area includes constructing gravity sewer systems.

A gravity sewer system uses gravity to gather wastewater from various sources to a central location, such as an area where it is legal to discharge wastewater or a treatment facility. Wastewater from each source (including residential homes and other buildings) goes to a network of sewer pipelines which become larger in diameter as the volume water of being transported becomes greater.

The pipes in the sewer pipeline network must have enough slope to keep suspended solids moving through the system. If there is not enough gravity flow throughout the system, lift stations are installed at lower portions of the network to pump the wastewater to a higher gravity pipeline. For maintenance purposes, manholes are installed at specific intervals along the pipeline network to provide access.

Well-designed and built gravity sewers are a reliable and feasible means of transporting wastewater. But in most instances the topography is far from ideal, requiring extensive excavation and lift stations for the gravity system to work. This makes construction expensive, hence, there must be adequate population density to justify the costs.