6.4 Wastewater treatment options

Septic tanks remove solids from sewage, but treatment is minimal and the effluent contains high levels of dissolved organic matter and ammonia. Other options for better treatment are available.

The aim in wastewater treatment is to:

• reduce the amount of biodegradable material and solids
• remove toxic materials
• eliminate pathogenic micro-organisms.

There are several ways of treating sewage and other wastewaters with different costs and requirements. One that is particularly effective and economical in warm regions of the world is waste stabilisation ponds.