Aerobic septic system

Many folks have a type of septic system that is commonly referred to as an “aerobic septic system” which uses a mechanical air pump to insert air into a tank or chamber which is referred to as the aerobic treatment unit (ATU).  This form of aerobic treatment is referred to also as secondary treatment.  This secondary treatment usually takes place in an ATU which is installed after the pretreatment tank and hence the name secondary treatment.  This secondary treatment which utilizes aerobic bacteria is a very effect method for breaking down waste but it does not make the effluent safe for human contact.  When the effluent leaves the ATU it has been through the secondary treatment process and it is typically a clear liquid with a slight odor but it still must be disinfected to an acceptable level in order to be deemed safe for contact with humans.  In some cases the effluent that leaves the ATU is filtered and then pumped through drip tubing for subsurface disposal and may or may not need to be disinfected first. After the effluent leaves the ATU and it is disinfected it is then stored in a pump tank for disposal.  There are many different brands and configurations for this type of aerobic septic system.  It is typical for smaller residential systems to have three tanks or a single tank with three chambers.  The first chamber is the pretreatment tank, the second is the ATU, and the third final chamber is the pump tank chamber.