- A. Dissolved oxygen
- B. Residual chlorine
- C. Biochemical oxygen demand
- D. Dose of coagulant
Environmental Engineering
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Orthotolidine test is used for determination of_____.
-
Corrosion in concrete sewers is caused by_____.
- A. Septic conditions
- B. Dissolved oxygen
- C. Chlorine
- D. Nitrogen
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The velocity of flow does not depend on_____.
- A. Grade of sewer
- B. Length of sewer
- C. Hydraulic mean depth of sewer
- D. Roughness of sewer
-
Period of cleaning of slow sand filters is about_____.
- A. 24 – 48 hours
- B. 10 – 12 days
- C. 2 – 3 months
- D. 1 – 2 year
-
Chlorine demand of water is equal to_____.
- A. Applied chlorine
- B. Residual chlorine
- C. Sum of applied and residual chlorine
- D. Difference of applied and residual chlorine
-
The slope of sewer shall be_____.
- A. Given in the direction of natural slope of ground
- B. Given in the direction opposite to natural slope of ground
- C. Zero
- D. Steeper than 1 in 20
-
The rate of filtration in slow sand filters in million litres per day per hectare is about_____.
- A. 50 to 60
- B. 100 to 150
- C. 500 to 600
- D. 1400 to 1500
-
The effective size of sand particles used in slow sand filters is_____.
- A. 0.25 to 0.35 mm
- B. 0.35 to 0.60 mm
- C. 0.60 to 1.00 mm
- D. 1.00 to 1.80 mm
-
The overflow rate for plain sedimentation tanks is about_____.
- A. 500 to 750 liters/hour/ m²
- B. 1000 to 1250 liters/hour/ m²
- C. 1250 to 1500 liters/hour/m²
- D. 1500 to 2000 liters/hour/m²
-
The specific gravity of sewage is_____.
- A. Much greater than 1
- B. Slightly less than 1
- C. Equal to 1
- D. Slightly greater than 1
- 1
- 2