A Glance on Aerobic Wastewater Treatment and the Process

Defining The Term Aerobic Process

The treatment process uses aerobes to biodegrade, oxidizes, or removes the unwanted organic or inorganic compounds. In this treatment of wastewaters, the methods can be divided into balanced growth processes like activated sludge process or attached growth processes such as rotating biological contactors or trickling filters that are used in the treatment. The aerobe is a microorganism that needs free or dissolved oxygen to develop to treat the wastewater.

Defining Aerobic Digestion

Aerobic digestion is a biological wastewater treatment where the sediments and substances such as oil contents are removed from wastewater. The process is done in the primary treatment stage as the aerobic treatments are used to break down organic matter by using oxygen.


Treatment Process

Activated Sludge Process

A continuous aerobic biological treatment for wastewater uses a culture of bacteria suspended in the wastewater in an aeration tank that absorbs the biodegrade and inorganic pollutants. Flocks are formed in the aeration tank. These are kept in suspension either by blowing air to the bottom of the reservoir as diffused air system or by mechanical aeration. The mixture of the activated sludge and wastewater in the aeration tank is known as the mixed liquor. The concentration of mixed liquor is termed as mixed liquor suspended solids that are measured as mixed liquor volatile suspended solids. Then the mixed liquor flows from the aeration tank to a sedimentation tank, where the activated sludge flocks combine into larger particles that settle like sludge. Hence, most of the sludge from the sedimentation tank returns to the aeration tank.

Rotating Biological Contactor

It is aerobic wastewater treatment plants in which a horizontal shaft is used above the surface of the wastewater that carries closely spaced discs or random plastics media in circular wire cages, which revolve with the shaft. The slow rotation of the process develops a biofilm, which oxidizes the wastewater. When the slime layer becomes too thick, it sloughs off and get settled in a separate tank or compartment.

Trickling Filter

It is an aerobic biological treatment plant and process for wastewater that works with a typical standard rate trickling filter where the wastewater trickles down through a thick bed of coarse stones. Many other types do exist, by using plastic media in a packed tower. This gain as in high rate trickling filters. Therefore, it is an attached growth process with a biofilm developing to make the wastewater and clean.


The benefits of aerobic treatment wastewater about anaerobic treatment are described as:

  • Good process  with the best stability
  • High effluent quality
  • Smaller sizes of the reactors

Closing Lines

Aerobic treatment is generally part of multistage water treatment processes. The technology is not limited to use as an intermediate stage, but it can also be used for finishing water and fulfill other types of treatments.


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