In the Water Treatment Plant, following process is adopted to remove colloidal impurities
- AScreening
- BAeration
- CSedimentation
- DFiltrationCorrect
Solution
Concept
Water treatment processes for colloidal impurities
Formula
NONE
Step-by-step solution
1. Colloidal impurities are fine particles that remain suspended in water after standard gravity sedimentation. 2. Coagulation and flocculation prepare these fine suspended and colloidal particles to be trapped during filtration. 3. Filtration effectively removes these remaining fine suspended and colloidal impurities by passing water through porous media. Answer: D
Explanation
Colloidal impurities are extremely fine particles that carry negative electrical charges and do not settle easily under gravity alone during plain sedimentation. In water treatment plants, coagulation and flocculation clump these particles together so they can be trapped and removed during the filtration process.
Why the other options are wrong
A) Screening removes large floating objects and coarse suspended solids. B) Aeration removes dissolved gases and oxidizes metals like iron and manganese. C) Sedimentation removes coarse suspended solids that settle readily under gravity.
Shortcut
Coagulation followed by Filtration removes fine colloidal impurities.
Common mistake
Confusing plain sedimentation with filtration for removing fine colloidal particles.
Correct answer: D) Filtration