Which characteristics define good quality activated sludge?

Good quality activated sludge is characterized by its ability to settle well in the clarifier, which allows for effective separation of solids from treated water. The brown coloration of the sludge indicates a healthy population of microorganisms, primarily due to the presence of active biomass that results from a well-functioning biological treatment process. Additionally, having some dissolved oxygen present is crucial because it signifies that the bacteria are actively metabolizing organic materials, thus contributing to the overall treatment efficiency. These attributes demonstrate that the activated sludge is performing its intended function in the wastewater treatment process.

In contrast, high dissolved oxygen levels and a green color may suggest the presence of algae, which is not a defining characteristic of good activated sludge quality. A low pH and clear appearance are not associated with effective activated sludge; a low pH might indicate acidity that can be harmful to bacterial populations, while clear appearance does not reflect the cellular activity and density required for effective wastewater treatment. High organic content with a bubbly texture might indicate poor treatment performance and is not typical of good quality activated sludge.