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Question #46571
The Question
During the secondary treatment of sewage, the vigorous growth of aerobic microbes into 'flocs' consumes organic matter, a process analogous to detritivory that obeys thermodynamic laws of energy transfer. If the influent entering the aeration tank is suddenly contaminated with high concentrations of non-biodegradable heavy metals, which of the following consequences is INCORRECT?
Options
- A.
The primary treatment phase will continue to separate grit and suspended solids, as it is independent of microbial metabolic flux.
- B.
The Biochemical Oxygen Demand (BOD) of the effluent leaving the aeration tank will remain high due to the collapse of the heterotrophic microbial population.
- C.
The rate of heat dissipation in the aeration tank will increase as the surviving microbes expend more energy to enzymatically degrade the heavy metals.
- D.
The volume of activated sludge formed will be severely reduced, subsequently limiting the production of biogas in the anaerobic sludge digester.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
BOD|Microbial Respiration|Energy Pyramid
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often assume microbes in an aeration tank can adapt to or degrade any waste, failing to distinguish between biodegradable organic matter (which fuels metabolism and heat release) and non-biodegradable toxins (which halt metabolism).
The trap relies on the misconception that cellular stress universally increases metabolic heat output, ignoring the non-biodegradable nature of heavy metals.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Microbes in Human Welfare - Class 12 |
| Concept | Primary vs Secondary Sewage Treatment |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |