In a water treatment plant, 'Micro-strainers' are specifically used to remove
- ALarge floating debris like branches and rags
- BCoarse sand and grit
- CAlgae and very fine suspended solidsCorrect
- DDissolved organic matter
Solution
Concept
Application of micro-strainers in treatment
Formula
NONE
Step-by-step solution
1. Water treatment pre-treatment uses varied screening devices depending on aperture size. 2. Coarse screens remove floating trash; grit chambers remove sand and grit. 3. Micro-strainers feature 15-45 micron fine fabric/mesh to capture microscopic algae and fine suspended solids. 4. Hence, micro-strainers specifically remove algae and very fine suspended solids. Answer: C
Explanation
Micro-strainers are rotary drum screening units fitted with extremely fine fabric or stainless steel mesh (openings typically 15 to 45 microns). In municipal water treatment works, they are deployed ahead of conventional units specifically to intercept and remove algae, plankton, and fine suspended matter, thereby preventing rapid filter choking.
Why the other options are wrong
A) Coarse bar screens and trash racks remove large debris and branches. B) Grit basins and detritus tanks remove coarse sand and grit. D) Dissolved organics require chemical coagulation, activated carbon, or biological treatment.
Shortcut
Micro-strainer = Microscopic algae and fine suspended matter removal.
Common mistake
Confusing micro-strainers with coarse screens or grit chambers.
Correct answer: C) Algae and very fine suspended solids