Sewage sickness refers to
- AToxicity of sewage interfering with treatment
- BDestruction of aquatic flora and fauna due to sewage
- CReduction in waste purifying capacity of soil
- DClogging of soil pores due to continuous sewage application on landCorrect
Solution
Concept
Sewage sickness of soil in land disposal
Formula
NONE
Step-by-step solution
1. Sewage disposal by land treatment relies on soil aeration to decompose organics. 2. Continuous irrigation causes grease, colloidal matter, and solids to accumulate in soil interstices. 3. Clogging of soil pores stops air circulation and induces anaerobic decomposition. 4. This phenomenon is termed sewage sickness of the soil. Answer: D
Explanation
When sewage is continuously applied to land for irrigation without adequate rest or rotation, solid particles and biological slimes fill up and clog the soil pores. This prevents atmospheric oxygen from penetrating the soil, halting aerobic oxidation and rendering the land foul, anaerobic, and unproductive—a condition known as 'Sewage Sickness'.
Why the other options are wrong
A) Sewage sickness specifically describes agricultural soil deterioration, not treatment plant toxicity. B) Destruction of aquatic life describes eutrophication/hypoxia in receiving waters. C) While purifying capacity drops, the direct defining physical mechanism is clogging of soil pores.
Shortcut
Sewage sickness = Clogging of soil pores by continuous sewage application.
Common mistake
Confusing sewage sickness of soil with human disease or river eutrophication.
Correct answer: D) Clogging of soil pores due to continuous sewage application on land