Final answer:
During aerobic secondary treatment of wastewater, bacteria and other organisms form an aggregate known as activated sludge where organic compounds are degraded.
Step-by-step explanation:
During aerobic secondary treatment of wastewater, bacteria and other organisms form aggregates called activated sludge, where degradation of organic compounds occurs.
This process is pivotal to treating wastewater as it helps break down and remove suspended and dissolved biological matter.
The activated sludge consists of a variety of microorganisms, including aerobic bacteria, that consume the organic components of sewage such as sugars and fats.
To facilitate this decomposition process, the sewage is aerated to ensure it is rich in oxygen, essential for the growth and respiration of the aerobic bacteria involved in the breakdown of contaminants.
In secondary treatment systems, aerated effluent is passed into a secondary clarifier, where microorganisms further decompose organic material and absorb nutrients.
After settling in the clarifier, most of the activated sludge is removed, with some being recycled back into the aeration process to seed the incoming wastewater with beneficial microorganisms.