Biodigesters and domestic waste water treatment

Biodigesters and domestic waste water treatment

Biodigesters for domestic waste water treatment enable 100% recycling of domestic waste water. The biodigester working mimics nature. The way water is treated is how the water would be treated in nature anyway. The difference is that the biodigester works faster and is compact. For a domestic system, a tank of 1000 litres is sufficient to completely digest waste and treat the waste water.

In a home or office, waste water comes from toilets, bathrooms, kitchen and sinks. The pollutants in this water are human waste, soaps and detergents, skin flakes, oils and fats and solid particles.

Human waste is largely organic. This can be degraded by bacteria thus reducing the mass of the waste. The water can then be recycled. Biodigesters treat black water. The grey water that leaves the bathrooms, sinks and hand wash basins bypasses the biodigester. However, solids, soaps, oils and fats must be removed from this water before recycling.

The principle of waste water treatment

Waste water is treated by aerobic or anaerobic means. With aerobic treatment, oxygen or air must be present. Anaerobic decomposition however can take place without theĀ  presence of oxygen.


Components of a complete biodigester with recycling

  • A bio-digester tank
  • A gulley trap
  • A grease trap
  • A recycling tank
  • Pumps and irrigation systems

Biodigester tanks

Biodigester tanks are designed to be incubators to bacteria and to provide all the conditions necessary for aerobic and anaerobic decomposition of organic waste. An enzyme is put into the tank to catalyze the process. Once installed properly, they function very well and exhausting is completely eliminated.

Gulley traps

Gulley traps are designed to capture solid particles in the waste water. This protects the bio-digester from filling up.

Grease trap

A grease trap uses the property of oil to float on the water and its viscosity to separate it from the water. Oil should be removed from the waste water before treatment. This allows easy aeration of water for bacterial action.

The recycling and irrigation system

The most effective way of recycling domestic waste water is to use it for lawn and garden irrigation. For this to happen, the water has to be collected and pumped to drip, sprinkler, farrow or hosepipe irrigation.