How do Advanced Onsite Wastewater Treatment Systems (AOWTS) differ from conventional septic systems, and are they worth the investment for challenging sites?

Question

Tyler Smith · Accepted Answer

Advanced Onsite Wastewater Treatment Systems (AOWTS), often referred to as aerobic treatment units (ATUs), represent a significant upgrade from conventional septic systems, especially for challenging properties. While both systems treat wastewater onsite, their methodologies and efficiencies differ substantially.

Key Differences:

1. Treatment Process: Conventional septic systems rely primarily on anaerobic bacteria in the septic tank to break down solids, with further treatment occurring passively in the drain field. AOWTS, conversely, introduce air into the treatment tank, promoting the growth of aerobic bacteria. These bacteria are far more efficient at breaking down organic matter and reducing pathogens, leading to a much cleaner effluent.
2. Effluent Quality: The treated wastewater, or effluent, from an AOWTS is significantly cleaner and contains fewer contaminants than that from a conventional system. This higher quality effluent is often suitable for discharge into areas with stricter environmental regulations or into smaller, less permeable drain fields.
3. Components: An AOWTS typically includes an aeration chamber, a clarifier (to settle out solids), and often a disinfection unit (like UV or chlorine tablets) before discharge. Conventional systems are simpler, consisting mainly of a septic tank and a drain field.
4. Footprint: Due to the higher treatment quality, AOWTS can often utilize smaller drain fields or alternative dispersal methods, making them ideal for properties with limited space, poor soil conditions, or high water tables.

Is the Investment Worth It?

Based on extensive feedback from property owners and regulatory bodies, the investment in an AOWTS is often justified for specific scenarios:

• Challenging Sites: If your property has poor soil percolation, a high water table, or limited space, a conventional system may not be feasible or compliant with local regulations. An AOWTS provides an effective solution where other systems fail.
• Environmental Sensitivity: In areas near sensitive waterways or drinking water sources, the superior effluent quality of an AOWTS helps protect the environment and meet stringent discharge standards.
• Long-Term Value: While the initial installation cost is higher, the enhanced treatment and potentially longer drain field life (due to cleaner effluent) can offer long-term savings and peace of mind. Many users report that the peace of mind regarding environmental impact and system reliability makes the initial expense worthwhile.
• Regulatory Compliance: Many jurisdictions now mandate advanced systems for new constructions or repairs in specific zones. Investing in an AOWTS ensures compliance and avoids potential fines or construction delays.

In summary, while AOWTS require a larger upfront investment and more complex maintenance, their ability to provide superior wastewater treatment for challenging sites and sensitive environments often makes them a highly valuable and necessary choice.