So, you’re thinking of installing a new on-site sewage facility (OSSF) for your wastewater needs, and the choice is down to a conventional vs. aerobic septic system. Both are approved for sewage in residential septic application and commercial septic applications, and Texas regulates the installation, repair and replacement of both.
The Anatomy of Conventional Septic Systems
and Aerobic Septic Systems
Conventional and aerobic septic systems are more similar than different from a design standpoint. However, the differences are important as conventional and aerobic wastewater systems treat effluent in two very different ways.
Conventional septic systems are built like this:
- The septic tank – The septic tank is the primary part of a conventional septic system, responsible for capturing and holding wastewater. With time, it will separate into three parts, including sludge (solid waste), scum (oils and other floating waste) and effluent (wastewater).
Most conventional septic tanks include two compartments, each with an access riser for inspection and maintenance purposes. As effluent moves into the second compartment, it travels from an outlet baffle to the system’s distribution box (optional) and drain field.
- The drain or leach field – The drain field is responsible for distributing the effluent into the ground, typically via a series of perforated tubes. At this point, the effluent can be treated by naturally occurring bacteria in the soil.
For larger properties, it may be necessary to route the effluent through a distribution box first, to ensure even drainage across multiple leach fields or other drainage structures.
Aerobic wastewater systems have many of the same components and are designed like this:
- The septic tank – Aerobic septic systems are also built with a septic tank, sometimes referred to as a trash tank. This tank is responsible for holding onto sludge and other waste solids to improve effluent treatment. Given the increased emphasis on treatment in an aerobic system, the trash tank is smaller than a conventional septic tank.
- The aerobic treatment unit – The aerobic treatment unit (ATU) is the heart of the aerobic system and uses oxygen to feed aerobic bacteria responsible for breaking down waste. The ATU consists of a separate compartment and an air pump that delivers air from the surface into the tank. As this air is circulated into the aerobic treatment tank, aerobic bacteria use it to break down waste solids and to eliminate pathogens in the effluent.
- The clarifier and pump tank – The clarifier is a small, separate tank (sometimes referred to as a pump tank) connected to the ATU and responsible for directing treated effluent to the treatment tank or the drain field.
- The treatment tank (may be optional) – Before dispersal to a drain or leach field, the effluent may be passed through a final treatment process that involves chlorine or UV disinfection.
- The drain field – Aerobic septic systems also rely on various drainage methods to disperse treated effluent. This could be via a set of perforated tubes and trenches, or via a sprinkler or other irrigation system.
Some septic experts can provide installation, inspection, repair and replacement services for both types of wastewater technologies – but not all can. Therefore, it’s important to choose the right expert to install or replace your septic system and to ensure proper septic system maintenance.
Texas Requirements for Conventional and Aerobic System Installation
OSSFs are regulated by the Texas Administrative Code, which includes rules governing the following:
- The size of the septic tank (which must meet certain volume requirements)
- Certain aspects of the system’s design (like installing access ports/risers)
- Where the septic or trash tank can be installed (for example, away from drainage structures or water wells)
Texas counties may place additional regulations on how and where OSSFs can be installed. For instance, some counties don’t allow homeowners to install septic systems on their own or even perform maintenance.
No matter where you or your business resides in Texas, you’ll have to attain a permit before installing, repairing, replacing or altering the design of your conventional or aerobic septic system. Part of the permitting process involves a site inspection performed by an approved septic expert or an engineer. During this inspection, the septic expert will analyze the site’s soil and confirm that it is stable enough for significant septic work.
Installation and Maintenance Costs for
Conventional vs. Aerobic Septic Systems
Installation and maintenance costs for conventional vs. aerobic septic systems will vary greatly across Texas. The property’s size and usage, the site’s layout and soil composition, how the treated effluent will be utilized or disposed of are all cost-related factors.
However, there are some general cost guidelines for property owners to consider:
- Conventional septic systems are usually the cost-efficient option – Conventional septic systems require fewer components than an aerobic septic system and don’t need a pump to function. As such, conventional septic tanks tend to cost less to install and maintain. On average, you’ll spend $2,000 to $3,000 more on an aerobic septic system, compared to a conventional septic system of similar size.
- Aerobic septic systems can be cost effective in certain instances – However, aerobic septic systems may be less expensive to install and maintain on smaller properties, where standard septic tanks may be more difficult to place. Further, aerobic septic systems are a better fit for applications where the effluent will be utilized, such as a source of irrigation on the property.
Overall, the choice between a conventional vs. aerobic septic system will be led by the property’s size, intended use and by local ordinances governing wastewater.
Signs That it’s Time to Replace Your Conventional Septic System or Aerobic Septic System
If your conventional or aerobic septic system is nearing the end of its useful life, you’ll likely notice some telltale signs, including:
- A distinct sewage odor – If the smell of sewage (similar to sulfur) is emanating from your drain field, it’s a sign that effluent isn’t being fully treated before reaching the drain field.
- Water backing up onto the property or slow drainage – If standing water is present in the drain field or if wastewater drains from the home slowly (like from toilets), your septic tank may be overwhelmed.
- Overgrown vegetation around the septic tank or drain field – When grass or other vegetation explode in lush growth around your septic tank or drain field, that’s a sign that wastewater is acting like a fertilizer for any plant growth.
If groundwater on and around your property is contaminated, that’s a clear sign that your septic system isn’t handling wastewater properly. If any of these signs are present, it’s time to schedule an expert inspection for your conventional or aerobic sewage system.
Consult with the Septic Experts When Deciding Between a Conventional vs. Aerobic Septic System
Those who consider installing, maintaining or replacing their property’s on-site sewage facility may not realize their safety and environmental safety are both at stake. As such, it’s a good idea to call in the experts to ensure that neither are put at risk. Another important point on this is that in some parts of Texas, hiring a reputable septic system company is not just a good idea – it’s required.
A septic and aerobic system expert will ensure everything is done in compliance with state and local laws, ensure that your project can move forward as planned, and ensure that your new (or improved) septic or aerobic system is capable of handling the wastewater needs of your property.
