Presence of nitrogen and phosphorous in waste water discharged into lakes and ponds causes_______________?

Related Mcqs:

1. Waste/polluted water discharged from electroplating, blast furnace and coal mining industries contain mainly _____________ substances?

   A. Radioactive
   B. Organic
   C. Inorganic
   D. None of these

2. The main pollutant in waste water discharged from a petroleum refinery is oil (both in free and emulsified form). Free oil is removed by_________________?

   A. Biological oxygen pond
   B. Aerated lagoons
   C. Trickling filters
   D. Gravity separator having oil skimming devices

3. 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.

4. 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.

5. A rigid vessel containing three moles of nitrogen gas at 30°C is heated to 250°C. Assume the average capacities of nitrogen to be Cp = 29.1 J/mole.°C and, Cv = 20.8 J/mole.°C. The heat required, neglecting the heat capacity of the vessel, is__________________?

   A. 13728 J
   B. 19206 J
   C. 4576 J
   D. 12712 J

6. In a mixture of benzene vapor and nitrogen gas at a total pressure of 900 mm Hg, if the absolute humidity of benzene is 0.2 kg benzene/kg nitrogen, the partial pressure of benzene in mm Hg is__________________?

   A. 180
   B. 60.3
   C. 720
   D. 200

7. 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

8. Presence of nitrogen in high concentration in contaminated air reduces partial pressure of oxygen in lungs, thereby causing asphyxia (suffocation) leading to death from oxygen deficiency. Concentration of N2 in contaminated air at which it acts as a natural asphyxiate is ≥ _____________ percent?

   A. 84
   B. 88
   C. 80
   D. 92

9. 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

10. 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.