Qualitative RBC questions

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Joshua Kogan

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Hi everyone, I've created 5 free qualitative RBC questions to use in preparation for the WRE PM session.  Please share with your colleagues, and share your thoughts.  GOOD LUCK studying!!  Solutions to the problems are here: http://wrecrossfit.com/post/139234338746/rotating-biological-contractor-quiz-problem-1

Problem #1. All of the following are types of drive assemblies used to rotate an RBC, except:

a. high rate filter

b. roughing filter

c. standard rate filter

d. tertiary filter

Problem #2. When the temperature of the influent to a trickling filter is warmer than ambient air, the air will:

a. flow down through the media

b. flow up through the media

c. recirculate throughout the media

d. air temperature compared to influent temperature has no bearing on the air flow

Problem #3. Voids between the filter media in a trickling filter:

a. must be kept open to allow sloughing of biology and proper air flow

b. must be kept plugged to allow proper detention time of wastewater

c. must be kept plugged to allow for retention of biology in the filter

d. must be kept open to allow for visual inspections of filters

Problem #4. The best observed characteristic of biomass in a RBC can be described as:

a. being white in appearance denoting special bacteria are treating sulfur compounds

b. being black in appearance denoting biomass effectively using dissolved oxygen in treatment

c. being brown to grey in color, shaggy in appearance and uniformly covering the media

d. being brown to grey in color, smelling of sulfide and sloughing off, exposing many bare spots

Problem #5. A small community has a wastewater plant with an RBC system and experiences a high flow during the day and a very low flow during the night.  Which of the following is the most true statement describing the best operational parameters?

a. high loading during the day provides the biomass food, RBC experiences sloughing due to low loading at night.  Influent flows should be throttled during the peak times making use of an equalization tank, and secondary flows should be recycled at night.

b. high flows during the day provide a diluted influent and low flows during the night provide a concentrated influent.  Secondary flows should be recycled at a high rate during the day and reduced during the night.

c. these flow parameters are normal flows for an RBC system.  The operator should make very small adjustments throughout the day and night.

d. a flow equalization tank should be installed in the plant and only used when flows are consistent throughout the day and night.

 
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I thought maybe it was a typo for RCB (reinforced concrete box) but, judging by the context, I'm guessing not. 

 
Where can I find solutions to these problems? The link to solutions doesnot seem to work. Thanks!

 
I'm sorry, the previous website was closed and our new one (www.squarepegpossibility.com) is up and running, but I haven't added these questions there, yet.  This said, here are the answers:

1. Scratch this question.  The 4 answer options are incorrect.  Human error on this one -- mixed up question and answers, with another question.

2. B

3. A

4. C

5. A

Good luck on the exam!!

 
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