What is Secondary Treatment?
Secondary treatment (in the on-site septic industry) refers to a device that cleans your wastewater before it goes to your absorption field. Usually, this treatment device is installed downstream of your septic tank (prior to your septic absorption field or dosing tank) and treats the liquid effluent.
Secondary treatment benefits…
All regular septic absorption fields will fail over time. How long your system lasts is a function of the amount and strength of the wastewater you are putting into your system. It is generally understood how lots of water can stress your absorption system but the concept of waste strength is often under appreciated or not understood.
Over time, the soil surface at the bottom of your absorption field will develop a bio-mat (a layer of anaerobic bacteria) that grows into a gelly-type black mat that seals off the soil interface. This mat continues to grow and slows the rate of absorption, eventually causing the system fail (i.e. back up into your newly remodeled bathroom).
A secondary treatment device cleans your wastewater before it goes to your absorption field and can eliminate the formation of a bio-mat. An aerobic treatment unit cleans the wastewater by introducing ambient air (and oxygen) into the wastewater. This promotes the growth of aerobic bacteria inside the ATU which then consumes all of the available “goodies” in your wastewater. The result is clear, oxygen rich water exiting the ATU. If you have an existing bio-mat, the clear, treated wastewater carries the “good” aerobic bacteria into your absorption field where they feed on your bio-mat and break it down.
There are many brands and types of secondary treatment systems that utilized different methods to clean your waste water. There are Aerobic treatment units, recirculating media and sand filters, and algae and plant based systems just to name a few.
My favorite has been the Aero-Tech ATU. I’ve been recommending this system for a many years. My joint venture company, Meade Septic Supply LLC, is now the distributor for the Aero-Tech Aerobic Treatment Units (ATU) in Indiana, Michigan and other surrounding states.
The Aero-Tech ATU Systems:
- Treats Wastewater to a High Degree!
- CBOD5: 5 mg/L
- Total Suspended Soils (TSS): 6 mg/L
- Dissolved Oxygen at least: 4 mg/L
- Denitrification of 49%
- Requires very little maintenance
- Have an excellent warranty
- Have no diffuser stones to plug or compressors to wear out
- Runs silent (no noise)
Secondary Treatment Costs…
An Aero-Tech ATU for a single family home costs around $5,000-$6,000 installed. Contact an Aero-Tech Certified Installer for a price quote.
The bottom line…
An Aero-Tech ATU (secondary treatment device) can keep your new absorption field working a long, long, long time and may be able to fix your existing failed system.