Here we will discuss two modes of clarifier operation, solids contact and sludge blanket for upflow machines. Frankly, I am intimately familiar with these concepts of clarifier operation. The reason I know about this is because I have been involved with operation and troubleshooting of many upflow clarifiers and their own unique physical/chemical processes. (see Case Histories)

Probably, the main point I need to make here is to clearly define and differentiate between the two modes of operation. Based on my experience, what I have seen in the field, I am lead to believe that most operators are not aware of the two modes, and therefore, of course, not aware of any differences, the reasons why one might be used instead of the other, or even how to recognize one from the other. My definitions or explanations of solids contact and sludge blanket operation may not be formal, but they should be descriptive, practical, and clear enough for most journeyman operators to gain at least a superficial understanding.