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Question #46399
The Question
During the secondary treatment of nitrogen-rich industrial effluent in a stirred-tank bioreactor, a failure in the sparger system causes non-uniform oxygen distribution. This leads to the toxic accumulation of ammonia, causing a systemic failure of the activated sludge. Which of the following statements regarding this biological process is INCORRECT?
Options
- A.
The primary cause of ammonia accumulation is the oxygen-dependent inhibition of chemoautotrophic nitrifying bacteria such as Nitrosomonas and Nitrobacter.
- B.
The toxic feedback loop of ammonia inhibits the aerobic heterotrophic microbes present in the flocs, thereby preventing the reduction of Biochemical Oxygen Demand (BOD).
- C.
The systemic failure can be reversed by introducing anaerobic denitrifying bacteria like Pseudomonas to directly convert the accumulated ammonia into nitrogen gas.
- D.
The geometric design of the bioreactor is critical because the oxidation of ammonia to nitrites and nitrates is a strictly aerobic process requiring high dissolved oxygen.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Bioreactor Geometry|Activated Sludge Inoculum|Ammonia
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Substrate specificity in the Nitrogen Cycle.
Students often remember that Pseudomonas removes nitrogen (denitrification) but fail to recall the exact sequence: Ammonia -> Nitrite -> Nitrate -> Nitrogen gas.
The trap relies on the misconception that denitrifiers can act directly on ammonia, bypassing the obligate aerobic nitrification steps.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Excretory Products and Their Elimination - Class 11 |
| Concept | Nitrogenous Waste Classification |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |