Here are the answers to the Sept. 13, 2021 edition of TPO's Exam Study Guide:

1. Denitrification in the secondary clarifier is undesirable. Which of the following is the best method of minimizing denitrification of secondary clarifier sludge?

The answer to the question is B, proper RAS controls. Maintaining a consistent and controllable sludge blanket in the secondary clarifier by controlling the RAS rates in the activated sludge process is typically the best method. Higher HRT and elevated SRT rates are detrimental methods for this application. Denitrification of sludge in the secondary clarifier should be minimized to avoid negative effects to the final effluent.

2. New groundwater sources are:

The correct answer is D, required to conduct triggered source water monitoring as required by the Ground Water Rule and/or maintain four-log inactivation for viruses. New groundwater sources placed in operation after Nov. 30, 2009 are required to implement triggered source water monitoring or provide at least four-log inactivation/removal or a state-approved combination of these technologies and conduct compliance monitoring within 30 days of the source being put in service. More information pertaining to the Ground Water Rule can be obtained here.


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