- By Tom Frank
- In News
- Tags liquid, retention, scum layer, secondary treatment, septic systems, sewer system, sludge layer, tank, three layers, Tim Frank Septic, wastewater infrastructure
Septic tanks are an important piece of the wastewater infrastructure for the United States. Where city sewer systems are too expensive and impractical to install, especially in rural areas, septic tanks are the most viable option. This helps to keep costs low for homeowners, to protect the environment, and to ensure clean drinking water. However, in order for these septic systems to work properly, they must be maintained and go through routine septic pumping.
Almost all septic systems have several components that are universal. Typically, you have one or two septic tanks that are followed by your secondary treatment. This can include aeration, leech trenches, mounds, etc.
Basics of Septic Systems
The septic tank works by separating the waste coming from the house into three distinct layers. This is accomplished with retention time and gravity. As the water flows into the tank, a baffle, or inlet tee, will start the separation process by forcing the liquid into the center of the tank. The heavier waste will settle down to the bottom to form a “sludge layer.” The lighter wastes, such as fats, oils, greases, and toilet paper will then float to the top to form a “scum layer.” The middle layer that forms will be a clearer liquid, and it will leave through the outlet tee, which extends down into the middle layer.
The purpose of the outlet tee is to trap the “scum layer” and the “sludge layer” in the tank. Only allow the clearer liquid into your secondary treatment. Over time, the top and bottom layers will grow, and shorten the amount of retention time in the tank. This will cause solids to flow through the outlet tee and damage your secondary treatment and is more likely to happen when large quantities of water are used. For example, washing several loads of clothes in a single day.
To prevent solids from flowing to your secondary treatment, regular pumping of your septic tank is vital. It is usually recommended that your tank be pumped every two to three years. Your technician can help make these determinations based upon the number of people in the home, water usage habits, and the condition of the solids in the tank. By following the advice of these technicians, you will help extend the life of your septic system. This will not only help protect your wallet, but also the environment.