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 to control the amount of rising sludge are increasing return rates, increasing F/M ratio or decreasing sludge age. A quick easy way to check rising sludge is using a settleometer. Good sludge should remain settled for at least an hour before rising to surface. Understanding the clarifier process is a fundamental requirement for proper treatment plant operations.
What is the primary purpose of a Right-to-Know program?
The correct answer is B, to advise the employee of the hazards associated with the chemicals and materials they work with. In order for an employee to practice safety, he or she will need to be informed of the hazards in and around their work area. The Right-to-Know program developed by the employer is designed to provide all necessary information on any chemicals used for water treatment, laboratory procedures, cleaning, and maintenance applications. Material Safety Data Sheets (MSDS) or Safety Data Sheets (SDS) are used to provide the necessary information. The Right-to-Know station should be located in area accessible to all, and organized so information can be found quickly.
