Question

Match LIST-I with LIST-II:\[\begin{array}{|c|c|} \hline \textbf{LIST-I (Treatment method)} & \textbf{LIST-II (Principle / process involved)} \\ \hline \text{A. Trickling filter} & \text{IV. Attached growth} \\ \hline \text{B. Activated sludge process} & \text{III. Suspended growth} \\ \hline \text{C. Aerated lagoon} & \text{II. Mechanical aeration} \\ \hline \text{D. Oxidation pond} & \text{I. Symbiotic} \\ \hline \end{array}\] Choose the most appropriate match from the options given below:

• A. A - III, B - IV, C - II, D - I
• B. A - IV, B - III, C - I, D - II
• C. A - III, B - IV, C - I, D - II
• D. A - IV, B - III, C - II, D - I

Hint:

Wastewater treatment units are classified as attached growth (e.g., trickling filter) or suspended growth (e.g., activated sludge), with lagoons using aeration and ponds relying on algae-bacteria symbiosis.

Answer 1

The Correct Option is D

Step 1: Trickling filter. Microbes grow on media surfaces in this attached growth process. Therefore, A corresponds to IV.

Step 2: Activated sludge process. This is a suspended growth process. Therefore, B corresponds to III.

Step 3: Aerated lagoon. This process uses mechanical aeration for oxidation. Therefore, C corresponds to II.

Step 4: Oxidation pond. This process depends on the symbiotic relationship between algae and bacteria. Therefore, D corresponds to I.

Step 5: Conclusion. The correct matching is A - IV, B - III, C - II, D - I. The correct option is (D).