Domestic or on-site aerated sewage treatment systems take the outflow from a normal septic tank to treat it using natural biological processes.  

But to consume and break down organic material, the bacteria require a large and steady amount of oxygen.

Aerated wastewater treatment systems introduce this needed oxygen using electricity-driven pumps or air blowers. The air is bubbled past blocks with a large surface area, specially engineered for prolific growth of bacteria. This type of organism is known as aerobic bacteria, which breaks down waste much faster than anaerobic bacteria. Anaerobic bacteria are found in septic tanks, where oxygen is lacking; these bacteria will slowly break down solid matter over many years. 

With aeration treatment, such systems can process and recycle wastewater efficiently at high levels of treatment. They help families and businesses reduce their water usage and contribute to a greener New Zealand.