Which of the following is a key factor in the activated sludge process?

The activated sludge process is a widely used method in wastewater treatment that relies on biological processes to remove organic matter from wastewater. A key factor in this process is the injection of air into the wastewater. This aeration provides the necessary oxygen for the aerobic microorganisms within the activated sludge to thrive. These microorganisms, including bacteria and protozoa, feed on the organic pollutants in the wastewater, breaking them down and converting them into biomass, which can then be separated from treated water.

Maintaining proper aeration is crucial for optimizing the efficiency of the activated sludge process because it ensures that there is enough dissolved oxygen for the microorganisms to perform their metabolic functions effectively. Insufficient aeration can lead to poor treatment performance and potential failures in reducing pollutant levels.

While other factors like the presence of harmful toxins, the removal of fats and oils, and the use of chemically treated waters may influence the overall wastewater treatment process, they are not central to the mechanics of the activated sludge process itself as the injection of air is. Proper aeration is essential for maintaining a healthy population of microorganisms and achieving effective wastewater treatment.