Sludge Treatment MCQ with answer and solution

Concept

Disadvantages of aerobic digestion

Step-by-step solution

1. Aerobic digestion gives odour-free, stable sludge with good fertiliser value (these are advantages). 2. Its drawbacks are high power cost and the poor dewatering characteristics of the digested sludge.

Explanation

Aerobically digested sludge is more difficult to dewater than anaerobically digested sludge.

Why the other options are wrong

Odour reduction and degradation of organic acids are benefits. "Enhanced putrescible" is the opposite of the stabilisation achieved.

Shortcut

Aerobic digestion: stable and odour-free, but poor dewatering and high energy cost.

Common mistake

Choosing a benefit.