CWEA Grade 3 Lab Analyst Practice Exam

Activated sludge is a key component in the biological treatment process of wastewater. Its primary function is the consumption of organic matter by microorganisms present in the sludge. During this treatment process, bacteria and other microorganisms utilize organic pollutants in the wastewater as their food source. As these microorganisms metabolize the organic material, they break it down into simpler, less harmful compounds, thereby reducing the biochemical oxygen demand (BOD) of the effluent and significantly improving water quality.

This biological mechanism is crucial for effective wastewater treatment, as it aids in removing the bulk of pollutants that would otherwise remain in untreated water. The process typically occurs in aeration tanks where oxygen is supplied to support the growth of these microorganisms, facilitating the breakdown of organic compounds.

The other options do not accurately describe the primary function of activated sludge. For instance, filtration of solids pertains to the physical removal of particles from water and does not involve biological processes. Chemical detoxification refers to the neutralization of harmful chemicals, which usually requires chemical treatments rather than biological ones. Cooling wastewater is related to temperature control rather than the biological treatment processes that activated sludge provides.

Thus, the use of activated sludge for the consumption of organic matter is central to its role in wastewater treatment.