A simple quiz

This quiz is designed to help you determine if you've understood the basic principles presented. A more intricate design problem can be found in Metcalf and Eddy, 11-7. Click on the answer that best answers the question.

1. Examine the following statements about denitrification::
   1. It is an anaerobic process
   2. It only occurs in the presence of a few specific species of microbes
   3. It involve chemical reduction
   4. It is invariably beneficial to the ecosystem of a receiving body of water.
   5. It involves nitrogen in compounds: NO3, NO2 and N2.
      

   Which of the above statements are true:

   1. I and II
   2. I, III, and V
   3. I, IV, and V
   4. II, III, V

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2. You have been placed in charge a foundation that will grant $100,000 to a municipality for upgrade of their wastewater treatment facilities to include denitrification. Four cities apply for the grant. Based on the following geographical descriptions given, who would you give the funds to:

   1. Albany -- a large city located on the Hudson River
   2. Miami -- a large city whose wastewater effluent is delivered to the Atlantic Ocean
   3. Baltimore -- a large city perched on a major estuary (the Chesapeake Bay)
   4. Minden, Nebraska -- a small agricultural town near a large lake.

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3. In a oxidation ditch the level of oxygen is controlled by changing the level of the rotating brush aerators in the mixed liquor. Why do you suppose that the rotation velocity is not just increased instead?
   1. It would require more power
      
   2. The increased torque would prematurely damage the rotors.
   3. It doesn't really matter, either method would be effective.
   4. The detention times in the anaerobic zones would be insufficient.

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4. The town you live in is concerned that the local lake is eutrifying. As a result, The town council is considering upgrading the local sewage plant from secondary some form of tertiary treatment. Which piece of information would be most helpful to you right now(assume that the existing plant works fine):
   1. Phosphorus, not nitrogen is the limiting nutrient in the lake ecosystem.
   2. The kind of aquatic life that naturally inhabit the lake
   3. The strength of the influent to the sewage plant
   4. The pH of the lake.