Aerobic Biological Process
Aerobic processes use bacteria that require oxygen, so air is
circulated throughout the treatment tank and aerobic
bacteria breaks down the waste in the wastewater.
Some systems use a pre-treatment stage before the main
treatment, as well as sanitising prior to release into the
environment.
Pre-treatment process: Some systems reduce the solids
that the aerobic bacteria could not easily break to reduce
the chance of clogging the system.
Main treatment: Treats household wastewater and includes
both domestic greywater and blackwater. Forced air from
the air compressor is mixed with the wastewater where the
aerobic bacteria feed on organic waste in the water and
reproduce.
Solid wastes that the bacteria cannot process settle out as
sludge. Various aerobic treatment systems include a
secondary settling tank to facilitate the aerobic biological
process. The sludge is frequently pumped out of the system
to reduce opportunities for clogging.
Final treatment and disposal: This process prepares the
water for return to the environment. It may include
disinfection using chlorination or UV light, discharging the
water to a soil absorption field, filtering through sand
filters, drip irrigation, or evapotranspiration.