Understanding Sanitary Sewer Overflows

Sanitary Sewer

A sanitary sewer is an underground pipe for transporting sewage from houses and commercial buildings. Sewage is conveyed to a wastewater treatment facility where it is treated to control water pollution before the clean water is discharged to surface waters.

The City of Shreveport has a separate sanitary sewer system designed to transport sewage alone. Separate storm water drains convey rainwater and surface runoff directly to surface waters. In some communities, combined sewers convey sewage with stormwater runoff in one pipe.

Each house and commercial building is served by a private service lateral. The service lateral conveys sewage from the property to the City’s sanitary sewer. An overview of a typical service lateral connection to the sanitary sewer is presented below.

Why do Sanitary Sewer Overflows occur?

One major cause of sanitary sewer overflows (SSOs) is blockage in sewer pipes. Excess rainwater entering pipes also causes overflows. However, SSOs can occur for a number of reasons that are described below. You can help keep rainwater out of the pipes by landscaping your yard so that water flows away from your house and foundation drains, and by installing gutters to direct rainwater away from your house. Have the line that connects your house with the public sewer line (called a house lateral) inspected. Repairing broken laterals, which is the homeowner’s responsibility, can reduce stormwater from leaking into pipes and prevent sewer backups into your home.

System bottlenecks caused by improper grease disposal, inadequate maintenance and lack of cleaning.

  • Tree root rupture of underground pipes. 
  • Deterioration of the sewer system that occurs over time resulting in system failures, loss of power can disable sewer lift station pumps or treatment plant equipment.
  • Heavy rainfall can cause a large amount of stormwater to infiltrate sewerage lines
 

What Can We Do to Prevent SSOs?

Help prevent the buildup of Fats, Oils, and Grease (FOG). FOG may clog pipes, cause blockages, and is a major cause of SSOs. As a byproduct of cooking, FOG is usually found in: baking goods, butter, lard, shortening, cooking oil, fats and oil from cooked meats, food scraps, gravy, mayonnaise, salad dressings, sauces, and sour cream. Dispose of these items in the garbage can. 

Here are a few simple tips to help control FOG:

  • Collect waste cooking oil in a can. Once the oil has cooled, place the can in a trash bag, seal tightly, and discard in the trash. Before washing, wipe oily pans thoroughly with a used paper napkin or paper towel.
  • Don’t scrape food from plates into your sink or garbage disposal; instead, wipe it off with a paper towel and compost it or toss it into the trash.
  • Install and maintain baskets, screens and or strainers over all sink and floor drains.
  • Catch food scraps and dispose of them in the garbage.
  • For restaurants, an appropriate cleaning schedule must be followed in order for
  • grease traps to function properly. Learn and follow local regulations.
 

It is critical to disconnect rain gutter down spouts, sump pumps, and yard area drains from the sanitary sewer because these connections allow a tremendous amount of water to enter the system. During wet weather this causes the pipe’s capacity to be exceeded and results in overflows into nearby ditches and streams or backup into homes. Removing these connections allows rainwater to flow naturally to storm sewers and waterways instead of overwhelming the City’s sewer system where it can cause overflows. Here are some actions that can be taken.

Disconnect downspouts, driveway or foundation drains, sump pumps or any other stormwater connection from the sanitary sewer system. 

  • Re-direct your downspouts so that water flows away from your house and foundation.
  • Landscape your yard so water drains into your yard or garden.
  • Route sump pump drains away from your foundation into your lawn or yard area. It is prohibited to have the sump pump connected to the sanitary sewer.
  • Have the line that connects your house with the public sewer line (called a house lateral) inspected. Repairing broken laterals, which is the homeowner’s responsibility, can reduce stormwater from leaking into pipes and prevent sewer backups into your yard or home.