Water And Wastewater Treatment Quiz-1 5j14b

Quiz-1 (Theory) PES-104: Unit Processes and Operations -1 (Physico-Chemical)

Roll. No.: Name:

1. Which of the following method is used for the removal of heavy metals from water/wastewater? a. Coagulation-flocculation settling b. Precipitation-flocculation-settling c. Adsorption d. Filtration 2. Membrane filtration technique can be used in a. MPN test b. BOD test c. Toxicity test d. None of these 3. Units for colloidal solids are a. FTU c. NTU

b. JTU d. All the above

4. Muffle furnace is needed in the estimation of a. TSS b. TDS c. VSS d. None of these 5. Which of the following is not possible a. Flow equalization without strength equalization c. Flow and strength equalization simultaneously

b. Strength equalization without flow equalization d. First flow equalization and then strength equalization

6. Why multiple effect evaporators are very energy efficient? a. The evaporation is brought about by waste b. Sensible heat of the vapours is repeatedly heat reused c. Latent heat is repeatedly reused d. The evaporation takes place under vacuum conditions 7. Phosphorus from water is removed by a. Coagulation-flocculation c. Precipitation

b. Neutralization d. None of these

8.

Which of the following are also known for reducing the MPN count in addition to suspended solids ad turbidity? a. Rapid gravity filters b. Roughing filters c. Slow sand filters d. Pressure filters 9. Which of the following is relatively less used in the water and wastewater treatment? a. Reverse osmosis b. Nanofiltration c. Ultrafltration d. Electrodialysis 10. Which of the following chemicals is usually used as a dechlorinating agent? a. Sodium hypochlorite b. Aluminum sulfate c. Sodium metabisulfite d. Ferrous sulphate

11. Degassifiers are used for a. Stripping removal of oxygen c. Stripping removal of carbon dioxide

b. Stripping removal of ammonia d. Stripping removal of volatile organic compounds (VOC)

12. Which of the wastewaters have the highest TDS level a. Ion-exchange resin bed backwash water b. Chemical run of the Ion-exchange resin bed regenration c. Slow rinse water d. Rapid rinse waer 13. Reciprocating rake type bar screens are a. Front clean – front return type screens c. Back clean – back return type screens

b. Front clean – back return tye screens d. None of these

14. Which of the following is not true for a grit chamber? a. Gravity force is larger than the buoyant force b. Acceleration of the settling particle is zero c. Particles settle at terminal settling velocity d. Drag force of a settling particle increases continually 15. In grit channels/chambers, the following does not influence the grit settling? a. Grit channel/chamber width b. Grit channel/chamber length c. Grit channel/chamber depth d. Surface area of the grit chamber 16. Proportional weir used in grit channels is meant for a. Ensuring constant horizontal flow velocity b. Dampening variations in flow rates c. Maintaining the depth of flow constant d. All the above 17. Purpose served by vanes provided in the inlet of the grit chambers is a. Ensuring uniform flow velocity across the grit b. Ensuring uniform flow velocity across the grit chamber depth chamber width c. Ensuring tangential entry of water into the grit d. Preventing entry of floating material into the chamber grit chamber 18. In the aerated grit chamber, the air used serves the following purpose a. Maintaining constant horizontal flow velocity b. Imparting centrifugal force and facilitating grit particles separation c. Oxidizing the suspended organic matter d. Cleaning the grit chamber through removal of separated along the grit in the grit chamber separated grit and suspended organic matter 19. Centrifugal force plays key role in the following? a. Cyclone grit separators b. Vortex type grit chambers c. Aerated grit chamber d. All the above 20. Which of the following coagulant requires aeration? a. Alum b. Ferrous sulfate c. Poly-aluminum chloride d. Ferric chloride 21. Coagulation-flocculation is meant for the removal of the following by design a. Coliform bacteria b. Nematode eggs c. Protozoan cysts d. None of these 22.

Brownian motion brings about the following

a. Microflocculation c. Coagulation

b. macroflocculation d. none of these

23. Velocity gradient plays important role in a. Perikinetic flocculation c. Perielectric coagulation

b. Orthrokinetic flocculation d. All the above

24. Optimum pH for Alum precipitation is a. <5 pH c. 7-9 pH

b. 5-7 pH d. >9 pH

25. Bentonite clay or clay particles are often used in the coagulation-flocculation process as a. Colloidal solids b. coagulating agents c. Flocculating agents d. None of these 26. Sludge blanket unit is a. An anaerobic digester c. a unit where coagulation, flocculation and settling all occur in one unit

b. A secondary clarifier d. A unit where both coagulation and flocculation occur

27. Which of the following are removed from the water/wastewater in the primary clarifiers? a. Colloidal solids b. Dissolved organic matter c. Dissolved BOD d. None of these 28. In rectangular sedimentation tanks the settled sludge is collected together at a. Mid-distance of the tank in the bottom b. Outlet end below the overflow baffle c. Mid-distance of the tank over water surface d. At the inlet end below the inlet section 29. What should be experimental settling column depth? a. 2.0 m b. 2.5 m c. 3.0 m d. Equal to the side wall liquid depth of the proposed circular primary clarifier 30. Which of the following is true regarding the central rotating mechanism? a. Brings the settled sludge to one point in the b. Brings the floating scum to one point in the rectangular clarifiers rectangular clarifiers c. Brings the settled sludge to one point for d. Brings the floating scum to one point for removal in the circular clarifiers removal in the circular clarifiers