Primary

The separation of suspended material from wastewater in septic tanks, primary settling chambers, or other structure, before effluent discharge to either a secondary treatment process, or to a land application system.

Secondary

Aerobic, biological processing and settling or filtering of effluent received from a primary treatment unit.

Disinfected

The method of treatment of wastewater which kills or inactivates microbial pathogens to an acceptable level, satisfactory for the intended use. Its effectiveness is typically measured by the reduction in faecal indicator bacteria E. coli