A. Alum (aluminium sulphate)
B. Lime
C. Ferric chloride
D. Sodium aluminate
A. Hearing loss
B. Rupture of ear drum
C. Nervousness & fatigue
D. All A., B. & C.
A. Colloids or aerosols
B. Powder
C. Dust
D. Smoke
A. Are large shallow artificial lakes also known as clarification lakes, maturation ponds or
oxidation ponds
B. Use micro-organisms/bacteria in presence of dissolved oxygen
C. Gives an excellent final effluent (with 3 to 4 lagoons arranged in series) having suspended
solid < 1 mg/litre and BOD = 3.8 mg/litre
D. All A., B. & C.
A. 3
B. 30
C. 7
D. 70
A. 1
B. 25
C. 150
D. 650
A. Foaming
B. Odour nuisances
C. Undesirable plant growth
D. Turbidity
A. Photochemical smog
B. Sulphur dioxide
C. Nitrogen dioxide
D. Dust particles
A. A primary pollutant
B. A secondary pollutant
C. Impervious to ultra-violet rays
D. Both B. and C.
A. Sterilisation
B. Aeration
C. Disinfection
D. None of these