A. Coagulation and flocculation of colloids
B. Oxidation of carbonaceous matter to CO2
C. Nitrification or oxidation of ammonia derived from breakdown of nitrogenous organic matter
to the nitrite and eventually to the nitrate
D. All A., B. and C.
Related Mcqs:
- Aerobic biological oxidation ponds used for the purification of polluted water__________________?
A. Destroys/removes pathogen from the sewage
B. Is not very effective for non-biodegradable substances (e.g. ABS) containing effluents
C. Destroys/removes pathogen much more effectively if the sewage is chlorinated
D. All A., B. & C. - Biological oxidation ponds remove organic matters present in the polluted water by _______________?
A. Using the activities of bacteria and other micro organisms
B. Aerobic oxidation
C. Both A. & B.
D. Neither A. nor B. - Disinfection of water is done to destroy pathogenic bacteria and thus prevent water-borne diseases. Disinfection of water may be done by the use of_________________?
A. Ozone and iodine
B. Chlorine or its compounds
C. Ultraviolet light for irradiation of water
D. All A., B. & C. - The amount of chemical coagulant added for treatment of polluted water ______________ with increase in temperature of the polluted water to be treated?
A. Decreases
B. Increases
C. Remain constant
D. May increase or decrease; depends on the chemical characteristics of polluted water - Thermal pollution of water increases its toxicity and oxidation of oxygen demanding waste besides favouring bacterial growth. A rise in water temperature by 10°C, doubles the toxic effects of _____________ present in it?
A. Coal ash
B. Potassium cyanide
C. Ortho-xylene
D. None of these - The type of bacteria which is active in trickling filter during biological treatment of sewage is the _____________ bacteria?
A. Anaerobic
B. Saprophytic
C. Aerobic
D. Parasitic - Presence of nitrogen and phosphorous in waste water discharged into lakes and ponds causes_______________?
A. Foaming
B. Odour nuisances
C. Undesirable plant growth
D. Turbidity - In sewage treatment, the detention period allowed for oxidation ponds ranges from _____________ weeks?
A. 1 to 2
B. 4 to 5
C. 9 to 10
D. 15 to 20 - Presence of soluble organics in polluted water causes_________________?
A. Undesirable plants growth
B. Depletion of oxygen
C. Fire hazards
D. Explosion hazards - Presence of bacteria in potable (drinking) water causes_________________?
A. Turbidity
B. Disease
C. Bad odour
D. Bad taste & colour
