Question

Which one of the following waste treatment system is devoid of any packing material, and it recycles internal biomass based on gravity?

• A. UASB
• B. FSSB
• C. RBC
• D. Trickling filter

Hint:

Remember: UASB systems are unique in being packing-free and using granular sludge that circulates via natural gravity and gas lift.

Answer 1

The Correct Option is A

Step 1: Understand what UASB stands for.
UASB stands for Upflow Anaerobic Sludge Blanket reactor. It is a wastewater treatment process that uses anaerobic digestion to treat effluents. Step 2: Key features of UASB.
It does not use any packing or filter media.
Biomass forms granular sludge that settles at the bottom.
Influent flows upwards, and the upward flow along with gas production causes mixing.
Biomass is recycled internally through gravity.
Step 3: Evaluate other options.
FSSB (Fixed Structured Surface Bioreactor) and RBC (Rotating Biological Contactor) use structured or attached media.
Trickling filters rely on media packing to support biofilms.