The sewage treatment units in which anaerobic decomposition of organic matter is used, are called________________?

Related Mcqs:

1. In very first stage of decomposition of the organic matter in sewage________________?

   A. Nitrites are formed
   B. Nitrates are formed
   C. Carbondioxide is formed
   D. Ammonia is formed

2. Assertion A. : Discharging the effluents from the oxidation ponds just up stream of lakes or reservoirs is undesirable. Reason (R) : The discharged algae get settled in the reservoirs and cause anaerobic decomposition and other water qualities_________________?

   A. Both A and R are true and R is the correct explanation of A
   B. Both A and R are true but R is not a correct explanation of A
   C. A is true but R is false
   D. A is false but R is true

3. The sewer which transports the sewage to the point of treatment, is called________________?

   A. House sewer
   B. Out-fall sewer
   C. Branch sewer
   D. Main sewer

4. To test chemical oxygen demand (C.O.D.) of sewage, organic matter is oxidised by potassium dichromate in the presence of_______________?

   A. Hydrochloric acid
   B. Sulphuric acid
   C. Nitric acid
   D. Citric acid

5. In sewage having fully oxidised organic matter, the nitrogen exists in the form of________________?

   A. Nitrites
   B. Nitrates
   C. Free ammonia
   D. Aluminoid nitrogen

6. For the COD test of sewage, organic matter is oxidised by K2Cr2O7 in the presence of________________?

   A. H2SO4
   B. HNO3
   C. HCl
   D. None of these

7. The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known_________________?

   A. Bio-Chemical Oxygen Demand (B.O.D.)
   B. Dissolved Oxygen (D.O.)
   C. Chemical Oxygen Demand (C.O.D.)
   D. None of these

8. In septic tanks, decomposition of organic bacteria, is done by_____________________?

   A. Anaerobic bacteria
   B. Aerobic bacteria
   C. Both types of bacterias
   D. None of these

9. If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is_________________?

   A. 100 mg/l
   B. 200 mg/l
   C. 300 mg/l
   D. 400 mg/l

10. The density of population over 40 hectares is 250/hectare. If water supply demand per day is 200 litres and sewage discharge is 80% of water supply, the sewage flow in sewers of separate system, is_____________________?

    A. 0.05552 cumec
    B. 0.05554 cumec
    C. 0.05556 cumec
    D. 0.0556 cumec