June 2007, Vol. 19, No.6

Certification Quiz

Test Your Knowledge of Nutrient Removal

    True or False Questions:
  1. Nitrification is the process in which organisms assimilate nitrogen gas, making it available to other organisms.
  2. Trickling filters use cyclic aeration to nitrify and denitrify wastewater.
  3. Following acid digestion of the Kjeldahl method, organic nitrogen is converted to ammonium ions.
  4. Denitrification processes show more slowing due to cold temperatures than enhanced biological phosphorus removal, nitrification, or sedimentation.

  5. Multiple Choice Questions:
  6. Which of the following choices is the primary parameter used for control of the activated sludge nitrification process?

  7. A. Dissolved oxygen concentration.
    B. Food-to-microorganism ratio.
    C. Hydraulic retention time.
    D. Solids retention time.

  8. Which of the following kinds of phosphorus should operators monitor in plant influent?

  9. A. Soluble phosphorus.
    B. Biodegradable phosphorus.
    C. Total phosphorus.
    D. Poly-phosphorus.

  10. Which of the following is the primary source of carbon used for denitrification in the modified Ludzack-Ettinger (MLE) process?

  11. A. Methanol.
    B. Carbon dioxide.
    C. BOD5 in influent wastewater.
    D. Endogenous respiration.

  12. What is the best volatile fatty acid to support enhanced biological phosphorus removal?

  13. A. Formic acid.
    B. Acetic acid.
    C. Valeric acid.
    D. Butyric acid.

Questions excerpted from Biological Nutrient Removal Operation Study Guide and reviewed by the Association of Boards of Certification (Ames, Iowa) Validation and Examination Committee.

Answer Key:
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Water Environment Federation and American Society of Civil Engineers/Environmental and Water Resources Institute (2005). Biological Nutrient Removal Operation Study Guide. Alexandria, Va.: Water Environment Federation.