Wastewater flows into the tank and settles in the central biozone chamber where it is aerated through the central diffuser.

A course bubble diffuser, housed in a draft tube, introduces the air that provides oxygen to the bacteria which then treats the wastewater.

The treated water then enters the outer settlement zone. Here, settled solids are drawn back to the draft tube and returned to the biozone chamber for further treatment.

The final treated effluent leaves the Biotech BTA ASP via a weir at the outlet level that extends around the circumference of the tank. The movement and exit of water throughout the ASP is by gravity displacement