Exam Study Guide: Aeration Tank Nitrification and Consumer Complaints

Maintaining your education is important, especially in a career that demands licensing exams. Prove you’re an expert operator by answering these questions and others from our Exam Study Guide Series.
Exam Study Guide: Aeration Tank Nitrification and Consumer Complaints

Welcome back to TPO magazine's new and improved Exam Study Guide Series, which offers a pair of water/wastewater study questions each week with in-depth explanations of the answers. We covered a set of wastewater and drinking water treatment questions last week on the topics of Plant Operating Condition and Transmission Line Flow Rate. This week, you can test your knowledge about nitrification in aeration tanks, and consumer complaints about water. Take a look at the multiple-choice sample questions and answer explanations below.

Sample Question No. 1:

During nitrification in an aeration tank, which of the following parameters will decrease?

A) Alkalinity

B) Oxidation reduction potential (ORP)

C) Nitrate

D) Nitrite

Answer: The answer is A, Alkalinity. As nitrification progresses through the aeration tank, nitrifying bacteria consume some of the alkalinity present in the mixed liquor for their metabolic processes. They obtain their carbon source from carbon dioxide and bicarbonate alkalinity while at the same time some of these bacteria produce acids. This depletion of carbonate alkalinity and acid production will reduce the available alkalinity. Once the alkalinity drops to critical levels, nitrification can slow or stop, leaving ammonium or nitrite present in the mixed liquor. The other parameters listed (ORP, nitrate and nitrite) will usually be increasing as nitrification takes place. Nitrite will be produced, but should oxidize further to nitrate provided all the necessary conditions exist. It is estimated that about 7.14 parts of alkalinity are consumed for each part of ammonium oxidized to nitrate. 

Sample Question No. 2:

How should consumer complaints and questions be handled in the field by water distribution system operators?

A) Distribution system crew members should be able to answer routine questions, but direct all others to the local home owners association.

B) Distribution system crew members should direct ALL consumer questions to the Supervisor, not matter how difficult.

C) Shut off the consumers service until all complaints and questions are resolved.

D) Distribution system crew members should be able to answer routine consumer questions, but direct all other questions to their supervisor.

Answer: The answer is D, distribution system crew members should be able to answer routine consumer questions, but direct all other questions to their supervisor. It is generally accepted practice that water distribution system personnel be able to answer routine questions from their water service customers about things like water quality, general treatment questions, billing methods, etc. Please do not confuse this statement with the accepted practice set in place by your utility; you may have a different standard operating procedure (SOP) when dealing with public, and always follow your SOP. However, the AWWA “Water Distribution System Operator Training Handbook” recommends the response of answer choice D.

Above all, always remember that the ‘face of the utility’ may be the members of the water distribution system field crew that interacts with the public much more frequently than the water treatment plant operators and managers! Field crew members and supervisors should be trained to handle routine questions and situations while referring very technical questions or hostile situations to utility managers.

About the author: Ron Trygar is the senior training specialist for water and wastewater programs at the University of Florida’s TREEO Center. Previously, he was the wastewater process control specialist at Hillsborough County Public Utilities in Tampa, Florida. He has worked in the wastewater industry for more than 30 years in a variety of locations and positions. Trygar became a Certified Environmental Trainer (CET) in 1998 and has since provided training for associations and regulatory agencies such as Florida Department of Environmental Protection (FDEP); Florida Water and Pollution Control Operators Association Short Schools; USABlueBook; Florida Water Environment Association sponsored training events; and local school environmental programs. Working alongside the FDEP Northeast District, Trygar helped begin the Florida Rural Water Association and FDEP joint operator certification review classes that are still given around the state today. He holds a Florida Class A wastewater treatment operator’s license and a Florida Class B drinking water operator’s license.


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