A septic tank is an underground chamber made of concrete, fiberglass, or plastic through which domestic
wastewater (sewage) flows for basic treatment. Settling and anaerobic processes reduce solids and organics, but the
treatment efficiency is only moderate (referred to as “primary treatment”).
A septic tank is a watertight chamber made of brick work, concrete, fibreglass, PVC or plastic, through which
blackwater from cistern or pour-flush toilets and greywater through a pipe from inside a building or an outside toilet
flows for primary treatment. Settling and anaerobic processes reduce solids and organics, but the treatment is only
moderate. Effluent is infiltrated into the ground or transported via a sewer to a (semi-)centralised treatment plant.
Accumulating faecal sludge needs to be dug out the chamber regularly and correctly disposed of.