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1. What is the correct incubation time and temperature for the BOD test?

   1.   ?    5 days at 20°F
   2.   ?    5 days at 20°C
   3.   ?    20 days at 5°C
   4.   ?    5 days at 68°C

2. What type of BOD is measured when the sample being analyzed is first filtered?

   1.   ?    CBOD
   2.   ?    SBOD
   3.   ?    TBOD
   4.   ?    FBOD

3. Given the following data, what is the CBOD₅ loading on the aeration system of this facility?
   
   - Plant flow is 2.75 mgd
   - Influent CBOD₅ is 225 mg/L
   - Primary clarifier CBOD₅ removal is 30%

   1.   ?    5,160 lbs/day
   2.   ?    1,548 lbs/day
   3.   ?    2,578 lbs/day
   4.   ?    3,612 lbs/day

4. What typically happens to the activity rate of the microorganisms as the temperature of the wastewater decreases?

   1.   ?    It speeds up
   2.   ?    It slows down
   3.   ?    Temperature of the wastewater has nothing to do with activity rate of the bugs
   4.   ?    It’s cut in half

5. What type of phosphorus is soluble and not particulate?

   1.   ?    Poly-phosphate
   2.   ?    Organic-phosphate
   3.   ?    Ortho-phosphate
   4.   ?    Agoro-phosphate

6. Which two flow streams typically combine together to make-up mixed liquor?

   1.   ?    Influent and secondary effluent
   2.   ?    Influent and primary effluent
   3.   ?    Primary effluent and waste activated sludge
   4.   ?    Primary effluent and return activated sludge

7. Which type of activated sludge process typically has an F/M ratio of about 0.2 to 0.5 and an SRT of about 5 to 15 days?

   1.   ?    High rate aeration
   2.   ?    Conventional aeration
   3.   ?    Endogenous respiration
   4.   ?    Pure oxygen

8. Which type of bacteria must have free dissolved oxygen to survive?

   1.   ?    Anaerobic
   2.   ?    Anoxic
   3.   ?    Facultative
   4.   ?    Aerobic

9. What is it called when mixed liquor never settles properly and remains either suspended or rising in the secondary clarifier?

   1.   ?    Rising sludge
   2.   ?    Bulking sludge
   3.   ?    Sludge blanket
   4.   ?    Nitrification

10. Which flow pattern typically combines the influent wastewater (or primary effluent) and RAS before it enters the beginning of a rectangular aeration tank. The combined flow then travels straight through the tank and leaves at the other end?

    1.   ?    Complete mix
    2.   ?    Contact stabilization
    3.   ?    Plug flow
    4.   ?    Step feed

11. Which statement best describes denitrification?

    1.   ?    NH₃ + O₂ = NO₂
    2.   ?    NO₂ + carbon = NH₃
    3.   ?    NO₃ + O₂ = NO₂
    4.   ?    NO₃ + carbon = N₂

12. Which two laboratory analyses are required to calculate the F/M ratio?

    1.   ?    Influent CBOD₅ and MLSS
    2.   ?    Effluent CBOD₅ and TSS
    3.   ?    MLVSS and influent TOC
    4.   ?    Influent CBOD₅ and MLVSS

13. A high rate aeration system (not pure oxygen) typically has a low MLSS concentration and high F/M ratio … is this system considered to be over-loaded or under-loaded?

    1.   ?    Over-loaded
    2.   ?    Under-loaded
    3.   ?    F/M ratio has nothing to do with loading
    4.   ?    Loading is based on sludge age

14. What is another way of saying mg/L?

    1.   ?    ppm
    2.   ?    7.48 gals per ft³
    3.   ?    8.34 lbs per million gallons
    4.   ?    Both a and c

15. What is an intermediate oxidation state between ammonia nitrogen (NH₃) and nitrate nitrogen (NO₃)?

    1.   ?    CBOD₅
    2.   ?    TKN
    3.   ?    CO₂
    4.   ?    NO₂

16. What bacterial activity measurement is expressed as mg/L/hr?

    1.   ?    Respiration rate (RR)
    2.   ?    Dissolved oxygen (D.O.)
    3.   ?    Settleometer
    4.   ?    Oxygen uptake rate (OUR)

17. What condition can result in sludge on the surface of a secondary clarifier typically caused by a septic environment?

    1.   ?    Bulking sludge
    2.   ?    High rate aeration
    3.   ?    Rising sludge
    4.   ?    Over-wasting

18. What process control parameter is the result of aeration total solids inventory divided by total solids removed from the process?

    1.   ?    Gould sludge age (GSA)
    2.   ?    Solids retention time (SRT)
    3.   ?    Mean cell residence time (MCRT)
    4.   ?    Sludge yield

19. What term is used to describe liquid that is removed from a digester, between an upper layer of scum and a lower blanket of sludge?

    1.   ?    Subnatant
    2.   ?    Effluent
    3.   ?    Filtrate
    4.   ?    Supernatant

20. Which aeration system is typically operated in the endogenous respiration growth phase?

    1.   ?    Conventional activated sludge
    2.   ?    High rate aeration
    3.   ?    Extended aeration
    4.   ?    Log growth