Aerobic Septic System
An aerobic septic system uses oxygen to speed up the treatment of wastewater, making it a more efficient option compared to standard systems. By adding aeration, these systems provide cleaner effluent before it enters the drainfield, helping protect your soil and water table.
Aerobic Septic System at McNair Septic
An aerobic treatment system is like a pressure distribution system, but it introduces oxygen into the septic compartment to speed up the bio-microbial process. This system consists of a trash/dose combo tank, an aerobic treatment tank, and a drainfield (AKA leech field). The tanks must be placed accordingly so that they are downhill from the home/building’s plumbing. Waste enters one of two separate compartments in the trash/dose tank. As the compartment fills, waste flows through the outlet to the aerobic treatment tank. Here, an aeration pump constantly pumps air into the effluent to speed up the bio-microbial treatment process. Then the effluent is transported back to the trash/dose tank, where it enters the second chamber (pump chamber).
Further settling occurs in the pump chamber, ensuring that the pump does not send solid material to the drainfield. The pump chamber contains two floats: a low level/off float (lower) and a high-water alarm float (higher). Time dosing is set upon installation. The system will turn the pump on a set number of times each day for a set amount of time. If the system pumps too much effluent out of the pump chamber, the low level/off float will turn the pump off automatically until its next dose time. If the effluent level in the pump chamber rises too high between doses, the high-water alarm float will trigger an alarm which indicates that something is wrong with the system or that dose times need to be adjusted to occur more frequently.
After leaving the pump chamber, a valve box evenly distributes the effluent between pressurized lateral lines. The system must use a pump even if gravity flow can be achieved from the pump chamber to the drainfield. This is to ensure that the drainfield is pressurized and all parts receive the same amount of effluent. Each lateral line has orifices that allow the effluent to reach the soil throughout the entire drainfield at the same rate. The effluent then filters through the soil and is clean by the time it reaches the water table.
If the water level in the pump chamber ever reaches the high-water alarm float, the alarm will go off, indicating that there is something wrong with the system.
Aerobic treatment systems should have an operation and maintenance inspection done every six months for the first two years after installation, and once a year of operation after that. Concurring reports may need to be turned in to the county.
Septic systems are sized according to the amount of waste they will be treating, usually estimated by the number of bedrooms in the home. For non-residential buildings, water usage usually determines the size.
The most basic drainfields include parallel, 60-foot-long lateral lines that are spaced six to eight feet on center. More intricately designed drainfields may include lateral lines of varying lengths (from 36 to 60 feet) that branch out from the valve box in multiple directions.
Upon installation, the only parts of the system that will be visible from above ground are 24-inch riser lids above the tanks, access ports above the tanks, a valve box lid, and observation port lids at the ends of the lateral lines. Each of these lids will be flush with the final grade and can be walked on, mowed over or disguised to lessen noticeability.
Drainfields should be treated as fragile to increase their longevity. Large animals such as cows or horses should not be kept on drainfields and vehicles should not be driven over them. Vegetation with intrusive roots should not be planted near them. Finally, a home owner should
be mindful of what is going into the system.
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FAQs About Aerobic Septic Systems
How does an aerobic septic system work?
An aerobic system introduces air into the wastewater using an aeration pump, which speeds up the bio-microbial process. Waste first settles in a trash/dose tank, then moves to the aerobic treatment tank where it is aerated, and finally passes through the pump chamber to be evenly distributed into the drainfield.
Why choose an aerobic system over a traditional one?
Aerobic systems provide a higher level of treatment by using oxygen, producing cleaner effluent before it reaches the drainfield. This can be beneficial in areas with stricter regulations or where soil and water protection are priorities.
What kind of maintenance does an aerobic system need?
Aerobic systems require more frequent inspections than standard systems. They should be checked every six months for the first two years after installation, and annually after that.
Will the system be visible on my property?
The only visible parts after installation are 24-inch riser lids above the tanks, access ports, a valve box lid, and observation port lids at the ends of the lateral lines. All of these are flush with the ground and can be walked on, mowed over, or disguised.
How do I protect my aerobic septic system?
Drainfields should be treated as fragile. Avoid driving vehicles, keeping large animals like cows or horses on them, or planting vegetation with intrusive roots nearby. Homeowners should also be mindful of what goes into the system.
The Process
Planning
All we need is your parcel number or address to begin. We research your property in advance, gather details about your future plans, and may schedule a site visit or call. Any questions are addressed quickly to keep the process moving.
Soils Evaluation
Most projects start with a soil evaluation (perc test), the first step toward system approval. We handle everything—from digging and testing to county applications, fees, and paperwork—while keeping you updated every step of the way.
On-Site Septic System Design
After completing the soil evaluation, we quickly create a detailed, cost-effective septic design, typically within one to two weeks, that includes all calculations, maps, and specifications, while handling every detail of the submittal process for you.
Review and Permitting
Most counties allow up to three weeks to review septic designs and soil evaluations, though some return them sooner. Once approved, we’ll send you a copy and can also forward it to licensed installers so you can receive system bids.
Taking Care of You
We handle everything—even the required county as-built map—so your septic system is approved and recorded. With no complex contracts, we start right away and keep things moving. Consultations are always free, so call us anytime.
Support
We can assist you in finding reputable septic installation and maintenance companies that can service and maintain your new system.
