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Difficulty: EasyWater Pollution, Industrial Effluents, and Water Treatment

In water purification and industrial wastewater management, specific chemical and physical processes are used to eliminate target pollutants. Match each water treatment process on the left with its corresponding chemical function on the right.

  • CoagulationClumping fine suspended solids using coagulants such as potash alum
  • AerationExpelling dissolved volatile gases and oxidising soluble iron compounds
  • ChlorinationDestroying pathogenic microorganisms to sanitize water
  • Activated Carbon FiltrationAdsorbing dissolved organic impurities, dyes, and unpleasant odours

Answer

Coagulation matches with clumping fine suspended solids using coagulants such as potash alum; Aeration matches with expelling dissolved volatile gases and oxidising soluble iron compounds; Chlorination matches with destroying pathogenic microorganisms to sanitize water; Activated Carbon Filtration matches with adsorbing dissolved organic impurities, dyes, and unpleasant odours.
Each process corresponds directly to its functional role in water purification: Coagulation uses coagulants like alum to clump fine suspended matter; Aeration strips unpleasant volatile gases and oxidises soluble metals; Chlorination kills disease-causing microorganisms; Activated Carbon Filtration adsorbs dissolved organic impurities and odours.

Step-by-Step Solution

1
Identify the primary chemical mechanism of Coagulation
Coagulation uses salts like alum to neutralize particle charges, resulting in the aggregation of fine suspended matter into larger settled masses.
Alum provides trivalent cations (Al3+Al^{3+}) to destabilize colloidal suspensions.
2
Identify the primary chemical mechanism of Aeration
Aeration increases dissolved oxygen to oxidize dissolved ferrous iron (Fe2+Fe^{2+}) to ferric iron (Fe3+Fe^{3+}) and strips out foul-smelling gases like H2SH_2S.
Physical gas exchange and oxidation improve water taste and clarity.
3
Identify the primary biological mechanism of Chlorination
Chlorination serves as the final disinfection stage to eliminate harmful biological pathogens.
Chlorine generates active oxidizing species (HOCl/OCl−HOCl / OCl^-) that rupture bacterial cell walls.
4
Identify the primary physical mechanism of Activated Carbon Filtration
Activated carbon adsorbs non-polar organic contaminants, synthetic detergents, and residual pigments due to its extremely porous structure.
High internal surface area promotes strong Van der Waals forces to trap organic pollutants.

Key Concept

Municipal and Industrial Water Treatment Processes
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Topics

Water Pollution, Industrial Effluents, and Water Treatment

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