water treatment quiz

Quiz-T.2 (UCE-502: Water Supply Engineering)

1. A conventional water treatment plant is not designed for the removal of the following a. Dissolved solids b. Suspended solids c. Colloidal solids d. Pathogens 2. Which of the following is the best for the coincidental removal of pathogens from water? a. Coagulation-flocculation-settling b. Filtration c. Membrane filtration d. Water softening by lime-soda ash process 3. Soda ash is needed for the removal of the following during water softening a. Calcium hardness b. Magnesium hardness c. Temporary hardness d. Permanent hardness 4. In a water treatment plant a degasifier is meant for the removal of a. Oxygen b. Ammonia c. Hydrogen sulfide d. None of these 5. Dechlorination is not possible by a. Sulfur dioxide c. Activated carbon

b. Sodium sulfate d. Sodium metabisulfite

6. Multiple effect evaporator is energy efficient because of a. Vacuum evaporation of water b. Repeated use of sensible heat of the vapours c. Repeated use of latent heat of vapours d. All the above 7. Solar water stills are used to produce a. Soft water c. Hot water 8. Adsorption isotherms are used for a. Designing an activated carbon column c.

Estimating the adsorption capacity of powdered activated carbon

b. Distilled water d. None of these b. Estimating the requirement of powdered activated carbon d. Estimating the adsorption capacity of granular activated carbon

9. Which of the following is influenced by the particle velocity? a. Gravity force b. Buoyant force c. Drag force d. All the above 10. Surface hydraulic loading rate is not equal to overflow rate in a. Grit channel b. Primary sedimentation tank c. Secondary sedimentation tank d. Clari-flocculator

11. Sugar mills usually use the following for the clarification of the treated cane juice? a. Clari-flocculator b. Tube settler c. Plate settler d. Stacked clarifier 12. Overflow weir length provided in a rectangular primary sedimentation tank is influenced by a. Overflow weir loading rate b. Overflow rate and surface area of the tank c. Water flow rate d. All the above 13. Indicate the typical speed of the central rotating mechanism of a clari-flocculation tank? a. 1 to 3 revolutions/minute b. 1 to 3 revolution/hour c. 0.6 to 1.2 m/min. d. 0.6 to 1.2 m/hour 14. Water filtration is the highest in the following a. Slow sand filter b. Rapid gravity filter (open type) c. Rapid gravity filter (closed type) d. Roughing filter 15. Which of the following is specific to the removal of iron and manganese from water? a. Green sand b. Anthracite coal c. Filtralite d. Granular activated carbon 16. Which of the following is used in the Oxfam filters? a. Geotextile b. Geonet c. Geomembrane d. All the above 17. Which of the following require backwashing? a. Biosand filter b. Slow sand filer c. Vertical flow roughing filter d. None of these 18. Darcy’s flow usually occurs in a. Slow sand filter c. Roughing filter

b. Rapid gravity filter d. All the above

19. Which of the following can serve as both primary and secondary disinfectant? a. UV radiation b. Hypochlorite c. Chloramines d. Ozone 20. Tri-halo-methanes can be generated when the following is used as a disinfectant a. Chlorine gas b. Sodium hypochlorite c. Calcium hypochlorite d. All the above 21. In electro-chlorinators the disinfectant is produced from a. Sodium chloride b. Calcium chloride c. Hydrochloric acid d. Magnesium chloride 22. The disinfectant available in the form of tablets is a. Calcium hypochlorite b. Sodium hypochlorite c. Stabilized chloramines d. Stabilized chlorine dioxide

23. Twin oxide is actually a. Chlorine dioxide c. Calcium hypochlorite

b. Sodium hypochlorite d. None of these

24. Chloramines concentration is maximum in water when the chlorine dose on mass basis is a. < 5 times the ammonical nitrogen b. 5 times the ammonical nitrogen c. 7.6 times the ammonical nitrogen d. > 7.6 times the ammonical nitrogen 25. Reason for providing floor level ventilation in chlorine storage rooms a. Chlorine is highly toxic gas b. Chlorine gas is yellowish in colour c. Chlorine gas is highly soluble in water d. None of these 26. Which of the following involves removal of mainly the bicarbonate hardness? a. Dealkalization b. Decationization c. Deionization d. None of these 27. Which of the following resins is used for the removal of heavy metals? a. Weak acid cation exchange resin b. Weak base anion exchange resins c. Strong base anion exchange resin d. None of these 28. At break point chlorination which of the following forms of residual chlorine is found in water? a. Free residual chlorine b. Combined residual chlorine c. Both free and combined residual chlorine d. No residual chlorine 29. Which of the following disinfectants does not leave any residual disinfectant after primary disinfection? a. Ozone b. Chlorine dioxide c. Twin oxide d. All the above 30. Which of the following units is used in a conventional water treatment plant? a. Anion exchange resin bed b. Water softening unit c. Cation exchange resin bed d. None of these