Quiz: Civil Engineering
Topic: Environmental Engineering
Each question carries 1 mark
Negative marking: 1/4 mark
Time: 10 Minutes
Q1. The various treatment processes in a water treatment plant are listed below.
(a) A, B, E, C, D
(b) D, E, C, A, B
(c) A, B, C, D, E
(d) B, C, A, E, D
Q2. The length of sedimentation tank should be at least __ the breadth of the tank.
(a) One time
(b) four times
(c) Two times
(d) three times
Q3. The characteristics of fresh and septic sewage respectively are: –
(a) Acidic and alkaline
(b) Alkaline and acidic
(c) Both acidic
(d) Both alkaline
Q4. The Bangalore method of composting of solid waste is:
(b) anaerobic and aerobic
Q5. The design discharge for the combined sewer system shall be taken as
(a) equal to rainfall
(b) rainfall + 1 DWF
(c) rainfall + 2 DWF
(d) rainfall + 6 DWF
Q6. Which of the following method is used to forecast the population of old and very large city?
(a) Arithmetical increase method
(b) Geometric progression method
(c) Graphical method
(d) Logistic curve method
Q7. The volume (in milliliters) occupied by aerated mixed liquor containing one gram of dry solids after setting for 30 minutes is termed as:
(a) Allowable solids content
(b) Sludge volume index
(c) Liquor index
(d) Chlorination limit
Q8. Activated sludge process is an example of:
(a) Aerobic attached growth process
(b) Anaerobic suspended growth process
(c) Aerobic suspended growth process
(d) Anaerobic attached growth process
Q9. The gases which are generally evolved during anaerobic decomposition of sewage are______.
(a) CO₂ + NH₃ + SO₂ + CH₄
(b) CO₂ + NH₃ + SO₂
(c) CO₂ + NH₃ + H₂S
(d) CO₂ + NH₃ + H₂S + CH₄
Q10. The detention period of a septic tank is of the order of
(a) 2-6 hours
(b) 2-4 hours
(c) 12-36 hours
(d) 4-8 hours
Sol. the correct sequence of process in water treatment is-
Coagulation → flocculation → Sedimentation → Filteration → Chlorination.
Sol. The length of sedimentation tank should be at least four times the breadth of the tank. The breadth of sedimentation tank should be 10 to 12 m and depth should be 3 to 4.5 m.
Sol. The characteristics of fresh and septic sewage are Alkaline and acidic respectively.
Sol. The Bangalore method of composting of solid waste is anaerobic.
Sol. Design discharge for combine sewer= Rainfall+2DWF
Design discharge for separate sewer= 6×DWF
Where DWF= Dry weather flow
Sol. Arithmetical increase method is used to forecast the population of old and very large city. According to this method, the Population of town or city after ‘n’ decades is
▭(P_n=P_o+nx ̅ )
P_0= Present population
n = no. of decades
x ̅= Average of increase in population
P_n= Population after ‘n’ decades
Sol. Sludge volume index → Sludge volume index is defined as volume occupied in ml. by 1 gm. Of solid in the mix liquor when allow to settle for 30 min.
▭(SVI=(Settled Sludge volume (ml))/(MLSS(gm.)))
Sol. Activated sludge process is example of aerobic suspended growth system. Sludge generated in secondary sedimentation tank mostly consist of living and active micro-organism, hence it is referred as activated sludge.
Sol. the gases which are evolved during anerobic decomposition of sewage are carbon di- oxide (CO2), Ammonia (NH3), Hydrogen sulphide (H2S) and methane (CH4).
Sol. The detention period of septic tank is 12 to 36 hours.