A. Using the activities of bacteria and other micro organisms
B. Aerobic oxidation
C. Both A. & B.
D. Neither A. nor B.
Related Mcqs:
- Bacterial aerobic oxidation of polluted water in biological oxidation ponds is done to purify it. Presence of bacteria helps in____________________?
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. - 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. - 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 - Which is the best and the most effective method for the removal of organic contaminant present in the polluted water in very small quantity (say < 200 mg/litre) ?
A. Lagooning
B. Activated carbon adsorption
C. Biological oxidation pond
D. Chemical coagulation - 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 - 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 - Radioactive substances present in the polluted water stream can be removed by_________________?
A. Biological oxygen treatment
B. Coagulation and filtration
C. Adsorption in ion exchange materials
D. None of these - Iron & manganese present in the polluted water is removed by __________________?
A. Simple filtration
B. Oxidation followed by settling & filtration
C. Chemical coagulation
D. Chlorination only - 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 - The biological decomposition of organic substances in wastes controlled conditions is called_________________?
A. Incineration
B. Biological oxidation
C. Composting
D. None of these
