Using the four-stage water-treatment classification adopted in UGC NET 2024,…
2024
Using the four-stage water-treatment classification adopted in UGC NET 2024, match List I with List II.
List - I — Water treatment | List - II — Process |
|---|---|
(A) Primary | (I) Removal of wastes with the help of activated charcoal etc. |
(B) Secondary | (II) Ozonization and disinfection by ultraviolet rays. |
(C) Tertiary | (III) Removal of large pieces such as stick, stone, rags, plastic etc. |
(D) Advanced | (IV) Removal after flocculation and coagulation of wastes. |
Choose the correct answer from the options given below :
Answer: B. (A)-(III), (B)-(IV), (C)-(I), (D)-(II) — ConceptA staged water-treatment system removes progressively finer classes of contamination. Early operations separate coarse material; later operations…
- A.
(A)-(III), (B)-(IV), (C)-(II), (D)-(I)
- B.
(A)-(III), (B)-(IV), (C)-(I), (D)-(II)
- C.
(A)-(II), (B)-(III), (C)-(I), (D)-(IV)
- D.
(A)-(II), (B)-(III), (C)-(IV), (D)-(I)
Show answer & explanation
Correct answer: B
Concept
A staged water-treatment system removes progressively finer classes of contamination. Early operations separate coarse material; later operations remove smaller, suspended, or dissolved contaminants; final polishing targets resistant pollutants and microorganisms.
In the four-level terminology used in this item, coarse screening is primary treatment, coagulation–flocculation removal is secondary treatment, activated-carbon adsorption is tertiary treatment, and ozone or ultraviolet disinfection is advanced treatment.
Treatment-stage names can overlap across engineering references; for this PYQ, the exam-specific four-stage classification is the governing axis.
Application
Primary treatment corresponds to removal of large pieces such as sticks, stones, rags, and plastics, so (A) pairs with (III).
Secondary treatment corresponds to removal after coagulation and flocculation, so (B) pairs with (IV).
Tertiary treatment corresponds to removal with activated charcoal, so (C) pairs with (I).
Advanced treatment corresponds to ozonation and ultraviolet disinfection, so (D) pairs with (II).
Cross-check and contrast
The sequence progresses from visible debris to aggregated suspended waste, then adsorption of residual contaminants, and finally oxidation or disinfection.
Swapping activated-charcoal treatment with ozonation and ultraviolet disinfection reverses the tertiary and advanced stages in the four-level scheme used by the question.
Therefore, the matching is (A)-(III), (B)-(IV), (C)-(I), (D)-(II).