Civil Engineering – Waste Water Engineering Mock test – 2 Welcome to your Waste Water Engineering Mock test -2 Take an exciting test in Waste Water Engineering You have only 20 mins to complete the test (31 Questions) Wish you all the best!!! Name Email 1. In sewage having fully oxidised organic matter, the nitrogen exists in the form of A. nitrites B. nitrates C. free ammonia D. aluminoid nitrogen E. none of these.2. The presence of free ammonia in sewage, is detected by A. boiling B. adding pottassium permanganate C. adding sulphuric acid D. phenol-di-sulphuric acid.3. Dry water flow in a combined sewer, is A. industrial sewage B. domestic sewage C. storm water D. inclusive of domestic and industrial sewage but excludes storm water.4. In sewers the highest non-scouring velocity is achieved in A. glazed bricks sewers B. cast iron sewers C. cement concrete sewers D. stone ware sewers.5. The drop man holes are generally provided in sewers for A. industrial areas B. large town ships C. hilly town ships D. cities in plains.6. For design purposes, the normal rate of infiltration of ground water into the sewer, is A. 500 litres/km/cm B. 1000 litres/km/cm C. 1500 litres/km/cm D. 2000 litres/km/cm E. 2500 litres/km/cm.7. The small sewers are cleaned by A. flushing B. cane rodding C. wooden pills D. none of these.8. The clarigesters are A. circular septic tanks B. rectangular septic tanks C. circular Imhoff double tanks with bottom hoppers D. circular Imhoff double storey tanks without bottom hoppers.9. The digested sludge from septic tanks, is removed after a maximum period of A. 3 years B. 3.5 years C. 4 years D. 5 years.10. For providing an Indian type W.C., the R.C.C. slabs in the toilet portion A. should be sunk by 20 cm B. should be kept 20 cm above the adjacent portion C. should be sunk by 50 cm D. need not be sunk.11. The liquid wastes from kitchens, bath rooms and wash basins, is not called A. liquid waste B. sullage C. sewage D. none of these.12. The effluent of a septic tank is A. fit for discharge into any open drain B. foul and contains dissolved and suspended solids C. as good as that from a complete treatment D. none of these.13. Pick up the correct statement from the following : A. The larger the sewer in size, more will be velocity B. The smaller the sewer in size, less will be velocity C. The larger the sewer in size, no deposition will take place D. The larger the sewer in size, deposition will take place.14. Maximum permissible velocity 1.5 m/sec, is adopted in drains A. with beds of rocks and gravels B. lined with stones C. both (a) and (b) D. neither (a) nor (b).15. Fresh sewage may become stale in A. one hour B. two to three hours C. three to four hours D. six hours.16. During preliminary treatment of a sewage A. Oil and grease are removed from skimming tanks B. Floating materials are removed by screening C. Girt and sand are removed by girt chambers D. All the above.17. In a city the ratio of the drainage to sewage is 20, the percentage discharge passing through non-monsoon periods, is A. 5 B. 10 C. 15 D. 2018. The standard B.O.D. of water is taken for A. 1 day B. 2 days C. 3 days D. 5 days19. A manhole is classified as shallow if its depth is between A. 0.4 to 0.5 m B. 0.5 to 0.7 m C. 0.7 to 0.9 m D. 0.9 to 1.20 m E. 1.2 to 1.50 m.20. 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.21. he most dangerous pollutant in vehicular emissions is A. CO B. SO2 C. CO2 D. O3.22. The settling velocity of the particles larger than 0.06 mm in a settling tank of depth 2.4 is 0.33 m per sec. The detention period recommended for the tank, is A. 30 minutes B. 1 hour C. 1 hour and 30 minutes D. 2 hours E. 3 hours.23. It is customary to design a sewer for D.W.F. on the basis of A. average demand B. twice the average demand C. thrice the average demand D. four times the average demand.24. To prevent settling down of sewage both at the bottom and on the sides of a large sewer, self-cleaning velocity recommended for Indian conditions, is A. 0.50 m/sec B. 0.60 m/sec C. 0.70 m/sec D. 0.75 m/sec25. If the depletion of oxygen is found to be 2.5 mg/litre after incubating 2.5 ml of sewage diluted to 250 ml for 5 days at 20°C, B.O.D. of the sewage is A. 50 mg/l B. 100 mg/l C. 150 mg/l D. 200 mg/l E. 250 mg/l.26. Rate of flow of sewage is generally assumed A. more than the rate of water supply B. equal to the rate of water supply C. less than the rate of water supply D. at 150 litres per capita.27. The detention period for plain sedimentation water tanks, is usually A. 4 to 8 hours B. 8 to 16 hours C. 16 to 24 hours D. 24 to 36 hours.28. Pick up the correct statement from the following : A. The larger the sewer in size, more will be velocity B. The smaller the sewer in size, less will be velocity C. The larger the sewer in size, no deposition will take place D. The larger the sewer in size, deposition will take place.29. Nitrogen cycle of sewage, is A. Liberation of ammonia-formation of nitrites-formation of nitrates-liberation of nitrogen B. Liberation of nitrogen-liberation of ammonia-formation of nitrites- formation of nitrates C. Liberation of nitrogen-formation of nitrates-formation of nitrites-liberation of ammonia D. Formation of nitrates-formation of nitrites-liberation of nitrates-liberation of nitrates30. The effluent of a septic tank is A. fit for discharge into any open drain B. foul and contains dissolved and suspended solids C. as good as that from a complete treatment D. none of these.31. A drop manhole is provided if A. a sewer drops from a height B. a branch sewer joins the main sewer at higher level C. a lamp is inserted to check obstruction D. none of these.