Question

In a typical sag cuve the septic zone comes after the _ zone A. decomposition B. biochemical oxygen demand C. clean D. recovery

Answer 1

Option (A)

Step-by-step explanation:

In a sag curve diagram, there are five zones, which are serially ordered as

1. Clean zone
2. Decomposition zone
3. Septic zone
4. Recovery zone
5. Clean zone

The Septic zone comes after the decomposition zone.

In the decomposition zone, the waste materials undergoes decomposition, as a result of which, the dissolved oxygen present in it are gradually used up by the decomposers, and causes pollution.

And in the septic zone, the amount of dissolved oxygen further decreases and it supports only a few life forms in this environment.

Thus, the correct answer is option (A).

Answer 2

A. Decomposition Zone

Step-by-step explanation:

The oxygen sag or the zone of deficit in the steam at any point of time during the self-purification process is the difference between the actual DO content and saturated DO content. The decomposition zone comes after the clean zone where the wastes are decomposed due to the water Oxygen. After which the water enters the recovery zone. The clean zone is the zone where aquatic fish can be found.