Septic System Basics

When it comes to septic tanks and systems, there is a variety to choose from. The type of property you have will ultimately decide which type is best for you.

Let’s take a look at the different types so you can better make your decision.

Conventional Septic Systems

These are the most common and also go by the names Overflow, and Leach Field System. A standard “conventional” septic tank is one that is gravity fed. It consists of the septic tank, drainfield, and soil.

  • The Septic Tank
    The purpose is to separate solids from wastewater and to store and partially decompose as much solid as it can allow the liquids to pass through the drainfield.
  • The Drainfield
    This is a network of pipes laid in trenches or beds. It is where wastewater is discharged. It is known as an absorption or leach field.
  • The Soil
    This provides final treatment and disposal of wastewater (effluent) in the septic tank. After the effluent has passed into the soil, it is treated by organisms in the soil before going into the ground or surface water. The type of soil used in a septic system impacts the effectiveness of the drainfield.

Aerobic Septic System

Aerobic systems are not totally different from conventional septic systems because they both use natural processes to treat wastewater. The main difference is that aerobic septic systems need oxygen in order to get the job done. They use a mechanism that requires electricity to inject air and get it moving inside the treatment tank.

This is one of the reasons why aerobic systems cost more and need more routine maintenance than most other types of systems. But when they work correctly and are maintained, aerobic systems can be a great alternative to other septic systems.

How Do Aerobic Septic Systems Work?

As we mentioned, aerobic septic systems need oxygen to work. Bacteria actually help this process. Those bacteria that thrive in oxygen-rich environments serve as little worker bees to break down and digest the wastewater inside the aerobic treatment unit.

But this doesn’t happen all at once. There are different stages that need to happen in order for the process to be complete. There are so many different designs that it is hard to put them all into one typical system. Instead, we can look at the different stages to get a better idea of how an aerobic septic system works.


During the pretreatment step, the amount of solids in the wastewater is reduced before going into the aerobic unit. These can be anything from greases and oils to toilet paper and other things that people flush down the toilet.

If there’s too much solid material, the system can get clogged and it won’t work properly. There are are many pretreatment methods. The most popular are a septic tank, a primary settling compartment in the pretreatment unit, or a trash trap. While pretreatment is not required, it can greatly improve a unit’s performance.

Types of Aerobic Treatment Units

The aerobic treatment’s main job is to collect and treat household wastewater, like toilet water, bathwater and water from laundry. They come in several sizes and shapes. The two most common designs are suspended growth units and attached growth units.

Suspended Growth Units

This is the most common process aerobic units use to treat wastewater. An aeration chamber is the main part. That’s where air is mixed with wastewater.

Air must be forced into the aeration chamber by an air blower or through liquid agitation, since most home aerobic units are buried underground like septic tanks

After that process, the forced air then mixes with wastewater in the aeration chamber. The oxygen helps the aerobic bacteria to grow so that it digests the solids in the wastewater. When wastewater and oxygen mix it is called the mixed liquor. But, the bacteria cannot digest all of the solids in the mixed liquor. That’s why these solids eventually turn into sludge. While some designs allow the sludge to build up at the bottom of the tank, many aerobic units have what’s called a settling chamber or clarifier where extra solids can go.

The sludge goes back to the aeration chamber in the aerobic units that are designed with a separate settling compartment. There’s also bacteria in the sludge that helps the process along. The sludge does build up in most units and will need to be pumped out occasionally to avoid clogs.

Once the wastewater has passed through the aerobic unit, a disinfectant, like chlorine tablets will be used as a disinfectant. Ultraviolet light and liquid bleach chlorinators can also be used. For more information on these options, visit the chlorine tablets/alternatives section to see the liquid chlorinator and UV disinfection devices we carry and install.


After this process is complete, the water gets stored in a “pump” tank until a predetermined amount is collected. It is then dispersed. There are a couple of ways this can be done.

Surface application, sprinklers, and sub-surface drop, using drop emitter are one way. In case your water pump malfunctions, the pump tank also serves as a storage tank. If there is a high water situation, a high water alarm located in the tank will go off.

The area around your sprinklers or subsurface drip area should not be allowed to collect water. If water that did not originate from the septic system is collected, there could be problems in the dispersal area.

At NTS, we can outfit your septic system with an “auto dialer”. If the alarm goes off, the control box will automatically call us and alert us. This allows for a service call to be scheduled much quicker. This type of notification requires a special alarm box and a phone line that is supplied to the box. You cannot use your normal house phone line.

Which system should I install? Standard or Aerobic Septic System?

Our experienced and trained staff at North Texas Septic can help you choose which type of septic system is best for your property. Give us a call and we will send a technician to your house to answer any questions about septic tank systems and where they should be on your property. We can also give you a quote.

We are dedicated to helping our customers own a well-maintained septic system. “A septic system that has been treated kindly will treat you kindly in return.”

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