Study Guide Answer Key

Here are the answers to the May 5, 2022 edition of TPO's Exam Study Guide: What is the main cause of rising sludge in an activated sludge secondary clarifier? The answer to the question is B, denitrification. Rising sludge is common in secondary clarifiers, it normally is caused by denitrification due to excessive detention time. When the sludge is allowed to settle and has used all the available oxygen (DO), the sludge will begin to denitrify and release the nitrogen gas, and small particles of sludge will be carried to the surface. This should not be confused with sludge bulking. Some measures