Aerobic Treatment Units (ATUs): How They Differ from Conventional Septic Systems
Introduction
Aerobic Treatment Units (ATUs) are advanced septic systems designed to treat wastewater more effectively than conventional systems. Unlike traditional systems, which rely on anaerobic processes (without oxygen), ATUs use aerobic bacteria to break down waste more efficiently. This aerobic process allows for faster and more thorough treatment, making ATUs ideal for properties in environmentally sensitive areas or those with challenging soil conditions.
In this post, we’ll explore how ATUs work, their key advantages over conventional systems, and the maintenance required to keep them operating efficiently.
How Aerobic Treatment Units Work
In a conventional septic system, wastewater is treated anaerobically in the septic tank, with solids settling to the bottom and liquid waste (effluent) flowing to a drain field for further filtration. However, this process is limited in its ability to remove nutrients, and it can be slow in treating waste.
ATUs, on the other hand, use oxygen to enhance the breakdown of organic matter. This oxygen allows aerobic bacteria to thrive, breaking down waste more efficiently and reducing harmful contaminants before the effluent reaches the soil.
Key Components of ATUs:
- Aeration Chamber: This is where oxygen is introduced into the system to support aerobic bacteria. An air pump or blower forces oxygen into the chamber, allowing the bacteria to break down waste more quickly.
- Settling Chamber: After aeration, the wastewater moves to the settling chamber, where any remaining solids are separated from the treated effluent.
- Disinfection Unit: In some ATUs, a disinfection unit (such as a UV light or chlorine tablets) is used to kill harmful bacteria before the treated effluent is released into the drain field.
- Pump Chamber: The treated effluent is sometimes pumped out to the drain field or a designated dispersal area, depending on the system design.
Differences Between ATUs and Conventional Systems
| Feature | Conventional System | Aerobic Treatment Unit (ATU) |
|---|---|---|
| Oxygen Requirement | Uses anaerobic (without oxygen) processes. | Uses aerobic (with oxygen) processes for more efficient waste breakdown. |
| Treatment Speed | Slower treatment of waste, taking more time to break down solids. | Faster waste breakdown due to oxygen and aerobic bacteria activity. |
| Nutrient Removal | Limited ability to remove nutrients like nitrogen and phosphorus. | More effective at reducing nutrients, making it better for sensitive environments. |
| Effluent Quality | Produces lower-quality effluent that may contain more contaminants. | Produces cleaner effluent that is better for the environment. |
| Drain Field Requirements | Requires larger drain fields for effective filtration. | Requires smaller drain fields, as the effluent is cleaner and less likely to clog. |
| Soil Compatibility | May not work well in areas with poor or shallow soils. | Suitable for areas with challenging soil conditions (e.g., high water tables). |
Advantages of Aerobic Treatment Units (ATUs)
- Improved Effluent Quality
- ATUs produce much cleaner effluent than conventional systems, which reduces the risk of groundwater contamination. This makes them ideal for areas near water bodies or with high water tables, where untreated nutrients and bacteria can pose serious environmental risks.
- Better Nutrient Removal
- ATUs are more effective at removing nitrogen and phosphorus, which are major contributors to nutrient pollution and harmful algal blooms, such as red tide. This is especially important in places like Florida, where nutrient pollution can severely impact marine ecosystems.
- Smaller Drain Field Requirements
- Because the treated effluent is much cleaner, ATUs require smaller drain fields compared to conventional systems. This can be an advantage in areas where space is limited, or where soil conditions make it difficult to install a large drain field.
- More Suitable for Challenging Soil Conditions
- ATUs work well in areas with poor soil conditions, such as shallow soils, clay, or areas with high groundwater levels. In contrast, conventional systems may struggle to treat wastewater effectively in these environments.
- Faster Treatment Process
- The use of oxygen and aerobic bacteria speeds up the breakdown of waste, allowing ATUs to treat wastewater more quickly than conventional systems.
- Flexibility in Installation
- ATUs can be installed in places where conventional systems might not be feasible, such as near bodies of water, on small lots, or in environmentally sensitive areas.
Maintenance Requirements for ATUs
While ATUs offer several advantages, they do require more regular maintenance than conventional systems to ensure they operate efficiently.
Neglecting maintenance can lead to system failure, reduced treatment quality, and even environmental contamination.
1. Regular Inspections
- ATUs should be inspected every 6-12 months by a professional to ensure that the system is working properly. During inspections, the aerator, pumps, and filters should be checked for damage or wear.
2. Aerator and Pump Maintenance
- The air pump (or blower) is essential to the function of an ATU, as it provides the oxygen needed for aerobic bacteria to break down waste. Regularly check the air pump for any signs of wear, and clean or replace air filters as necessary.
- Ensure that the effluent pump is functioning properly to avoid any backups in the system.
3. Sludge Removal
- Over time, sludge (solid waste) can build up in the aeration and settling chambers. This sludge must be removed periodically to prevent it from clogging the system or reducing its treatment efficiency. Depending on the system size and usage, this may need to be done every 2-3 years.
4. Disinfection Maintenance
- If your ATU includes a disinfection unit (such as UV lights or chlorine tablets), these components must be regularly maintained to ensure they continue to kill harmful bacteria before the treated effluent is released.
- Chlorine tablets need to be replaced regularly (every few months), while UV lights should be inspected and cleaned annually.
5. Monitoring and Alarms
- Many ATUs come equipped with monitoring systems and alarms that notify homeowners if the system is malfunctioning. It’s important to ensure that these alarms are functioning properly and respond to any alerts promptly to prevent system failures.
6. Record Keeping
- Keeping detailed records of inspections, repairs, and maintenance activities helps track the health of the system and ensures that all necessary upkeep is being performed.
Conclusion
Aerobic Treatment Units (ATUs) offer a more efficient and environmentally friendly alternative to conventional septic systems, particularly in areas with challenging soil conditions or near sensitive ecosystems.
By introducing oxygen into the treatment process, ATUs break down waste more effectively and produce cleaner effluent, reducing the risk of nutrient pollution and groundwater contamination.
However, these systems require regular maintenance to ensure they continue to operate at their best.
Regular inspections, proper care of the aerator and pumps, and routine sludge removal are essential to keeping an ATU running smoothly and protecting the environment.
If you’re considering upgrading to an ATU or need help maintaining your existing system, contact us today for professional advice and services.