Environmental Engineering Important MCQs

1 - A pipe conveying sewage from plumbing system of a single building to common sewer or point of immediate disposal is called________________?






house sewer

2 - A pipe which is installed in the house drainage to preserve the water seal of traps is called______________?






antisiphonage pipe

3 - A pneumatic sewage ejector includes a tank for holding _________






Fluid sewage

4 - A sewer that receives the discharge of a number of house sewers is called________________?






lateral sewer

5 - Activated carbon is used for_____________?






removing odours

6 - Air binding phenomena in rapid sand filters occur due to_________________?






excessive negative head

7 - Alkalinity in water is expressed as milli-grams per litre in terms of equivalent_______________?






calcium carbonate

8 - Alum as a coagulant is found to be most effective when pH range of water is______________?






6 to 8

9 - An egg shaped section of sewer________________?






provides self cleansing velocity at low discharges

10 - As compared to cast iron pipes, steel pipes are______________?






stronger

11 - As compared to higher pH values, the contact period required for efficient chlorination at lower pH values is___________________?






smaller

12 - As compared to shallow-wells, deep wells have______________?






more discharge

13 - Assertion A: Slow sand filters are more efficient in removal of bacteria than rapid sand filters. Reason R : The sand used in slow sand filters is finer than that in rapid sand filters. Select your answer based on the coding system given below?






Both A and R are true and R is the correct explanation of A

14 - Average rate of water consumption perhead per day as per Indian Standard is______________?






135 litres

15 - Centrifugal pumps transfer energy from _______






Rotor to fluid

16 - Centrifugal pumps transport fluids by converting _________






Kinetic energy to hydrodynamic energy

17 - Chlorine demand of water is equal to________________?






difference of applied and residual chlorine

18 - Composting and lagooning are the methods of_______________?






sludge disposal

19 - Corrosion in concrete sewers is caused by______________?






septic conditions

20 - Disinfection efficiency is________________?






reduced at higher pH value of water

21 - Disinfection of water results in______________?






killing of disease bacteria

22 - Dissolved oxygen in streams is______________?






maximum at noon

23 - Double filtration is used_______________?






to increase the filtration slow sand filters capacity of

24 - Facultative bacteria are able to work in________________?






presence as well as in absence of oxygen

25 - For a country like India, where rainfall is mainly confined to one season, the suitable sewerage system will be________________?






separate system

26 - For a given discharge, the efficiency of sedimentation tank can be increased by______________?






increasing the surface area of tank

27 - For normal sludge, the value of sludge index for Indian conditions is________________?






150 to 350

28 - For satisfactory working of a sludge digestion unit, the pH range of digested sludge should be maintained as___________________?






6.5 to 8.0

29 - For the same solid content, if the quantity of sludge with moisture content of 98% is X, then the quantity of sludge with moisture content of 96% will be__________________?






X/2

30 - Gear pumps are ___________






Tangential flow pumps

31 - Gear pumps are mainly used in chemical installations because they pump ________






High viscosity fluids

32 - Gear pumps are used to transport ________






Fluid

33 - Gear pumps convert rotational kinetic energy to hydrodynamic energy.






TRUE

34 - Generally the detention period for grit chambers is kept as_______________?






1 minute

35 - Ground water is usually free from________________?






suspended impurities

36 - If the sewage contains grease and fatty oils, these are removed in_________________?






skimming tanks

37 - If the time of concentration is 9 minutes, then the intensity of rainfall according to British Ministry of Health formula will be__________________?






40 mm/hr

38 - If the total hardness of water is greater than its total alkalinity, the carbonate hardness will be equal to________________?






total alkalinity

39 - In chlorination, with the rise in temperature of water, death rate of bacteria____________?






increases

40 - In facultative stabilization pond, the sewage is treated by________________?






dual action of aerobic bacteria and anaerobic bacteria

41 - In lime-soda process________________?






lime reduces the carbonate hardness and soda-ash removes the non-carbo¬nate hardness

42 - In water treatment, rapid gravity filters are adopted to remove_______________?






bacteria and colloidal solids

43 - Laying of sewers is usually done with the help of________________?






sight rails and boning rods

44 - Most of the bacteria in sewage are______________?






saprophytic

45 - Most suitable section of sewer in separate sewage system is________________?






circular section

46 - On standard silica scale, the turbidity in drinking water should be limited to_______________?






10 ppm

47 - Orthotolidine test is used for determination of________________?






residual chlorine

48 - Percentage of bacterial load that can be removed from water by the process of plain sedimentation is about_______________?






75

49 - Period of cleaning of slow sand filters is about________________?






2-3 months

50 - Residual chlorine in water is determined by________________?






both (A) and (B)

51 - Scour valves are provided ______________?






at every depression and dead ends to drain out the waste water that may collect there

52 - Settling velocity increases with_______________?






depth of tank

53 - Sewage treatment units are designed for_______________?






average flow only

54 - Sewage treatment units are normally designed for______________?






15-20 years

55 - Sewerage system is designed for_______________?






maximum and minimum flow

56 - Sewerage system is usually designed for_________________?






25 years

57 - Sludge volume index is defined as the ratio of_______________?






percentage of sludge by volume to percentage of suspended solids by weight

58 - Standard BOD is measured at________________?






20°C – 5day

59 - The alum, when added as a coagulant in water_______________?






decreases pH value of water

60 - The amount of residual chlorine left in public water supply for safety against pathogenic bacteria is about______________?






0.05 to 0.5 ppm

61 - The characteristics of fresh and septic sewage respectively are____________________?






alkaline and acidic

62 - The chemical most commonly used to increase speed of sedimentation of sewage is_______________?






lime

63 - The correct relation between theoretical oxygen demand (TOD), Biochemical oxygen demand (BOD) and Chemical oxygen demand (COD) is given by_______________?






TOD>COD>BOD

64 - The depression of water table in a well due to pumping will be maximum_______________?






close to the well

65 - The design discharge for the combined sewer system shall be taken as________________?






rainfall + 2 DWF

66 - The design discharge for the separate sewer system shall be taken as_____________?






6xDWF

67 - The detention period and overflow rate respectively for plain sedimentation as compared to sedimentation with coagulation are generally_______________?






more and less

68 - The detention period for oxidation ponds is usually kept as______________?






10 to 15 days

69 - The detention period in coagulation tanks is usually kept as_______________?






2 to 6 hours

70 - The dissolved oxygen level in natural unpolluted waters at normal temperature is found to be of the order of________________?






10 mg/litre

71 - The distribution mains are designed for________________?






maximum hourly demand on maxi¬mum day

72 - The effect of increasing diameter of sewer on the self cleansing velocity is_____________?






to increase it

73 - The effective size of sand particles used in slow sand filters is_______________?






0.25 to 0.35 mm

74 - The gas from sludge digestion tank is mainly composed of __________________?






methane

75 - The hourly variation factor is usually taken as______________?






1.5

76 - The injection pumps used in most diesel engines can create up to ________






30000 psi

77 - The layout of distribution system in which water flows towards the outer periphery is_________________?






radial system

78 - The length of rectangular sedimentation tank should not be more than_______________?






4B

79 - The main disadvantage of cement concrete sewers is________________?






difficulty in transportation due to heavy weight

80 - The main disadvantage of oxidation pond is that________________?






large area is required for construction

81 - The main function of gear pumps are to ________






Transfer energy

82 - The major disadvantage of lime soda process of water softening is that_________________?






huge amount of precipitate is formed which creates a disposal problem

83 - The maximum discharge of a tube-well is about_________________?






50 litres/sec

84 - The maximum efficiency of BOD removal is achieved in______________?






oxidation ditch

85 - The maximum permissible limit for flouride in drinking water is______________?






1.5 mg/litre

86 - The means of access for inspection and cleaning of sewer line is known as_______________?






manhole

87 - The method of analysis of distribution system in which the domestic supply is neglected and fire demand is considered is________________?






circle method

88 - The minimum and maximum diameters of sewers shall preferably be_________________?






15 cm and 300 cm

89 - The minimum dissolved oxygen which should always be present in water in order to save the aquatic life is______________?






4 ppm

90 - The most common cause of acidity in water is_______________?






carbon dioxide

91 - The most common pump used for hydraulic fluid power application is __________






Gear pump

92 - The most commonly used sewer under culverts is_______________?






circular brick sewer

93 - The overflow rate for plain sedimentation tanks is about__________________?






500 to 750 litres/hour/ m2

94 - The pathogens can be killed by_______________?






chlorination

95 - The percentage of chlorine in fresh bleaching powder is about________________?






30 to 35

96 - The percentage of filtered water, which is used for backwashing in rapid sand filters, is about______________?






2 to 4

97 - The phenolic compounds in public water supply should not be more than_______________?






0.001 ppm

98 - The pipe which is used to carry the discharge from sanitary fittings like bath rooms, kitchens etc. is called_______________?






waste pipe

99 - The polluted water is one which_______________?






consists of undesirable substances rendering it unfit for drinking and domestic use

100 - The population of a town in three consecutive years are 5000, 7000 and 8400 respectively. The population of the town in the fourth consecutive year according to geometrical increase method is________________?






10920

101 - The process in which the chlorination is done beyond the break point is known as_________________?






super chlorination

102 - The process of lagooning is primarily a means of________________?






disposing of sludge

103 - The rate of Alteration of pressure filters is_________________?






greater than that of rapid sand filters

104 - The rate of BOD exerted at any time is_____________?






directly proportional to BOD remain-ing

105 - The rate of filtration in slow sand filters in million litres per day per hectare is about_____________?






50 to 60

106 - The ratio of 5 day BOD to ultimate BOD is about_______________?






44960

107 - The relative stability of a sewage sample, whose dissolved oxygen is same as the total oxygen required to satisfy BOD, is______________?






100

108 - The rotational kinetic energy comes from ______






Engine motor

109 - The self cleansing velocity for all sewers in India is usually_________________?






1.0 m/sec to 1.2 m/sec

110 - The settling velocity of a particle in a sedimentation tank depends on__________________?






surface area of tank

111 - The settling velocity of a particle in a sedimentation tank increases if______________?






none of the above

112 - The settling velocity of a particle in a sedimentation tank increases if_________________?






none of the above

113 - The slope of sewer shall be__________________?






given in the direction of natural slope of ground

114 - The specific gravity of sewage is_______________?






slightly greater than 1

115 - The suitable layout of a distribution system for irregularly growing town is_______________?






dead end system

116 - The suitable layout of distribution system for a city with roads of rectangular pattern is______________?






grid iron system

117 - The suitable method for disinfection of swimming pool water is________________?






ultra violet rays treatment

118 - The suitable system of sanitation for area of distributed rainfall throughout the year with less intensity is_________________?






combined system

119 - The time of concentration is defined as_______________?






sum of (A) and (B)

120 - The treatment of water with bleaching powder is known as________________?






hypochlorination

121 - The type of sewer which is suitable for both combined and separate system is_____________?






egg shaped sewer

122 - The type of valve which allows water to flow in one direction but prevents its flow in the reverse direction is____________________?






reflux valve

123 - The type of valve which is provided to control the flow of water in the distribution system at street corners and where the pipe lines intersect is_______________?






sluice valve

124 - The type of valve, which is provided on the suction pipe in a tube-well, is____________?






reflux valve

125 - The velocity of flow does not depend on_______________?






length of sewer

126 - The velocity of flow of water in a sedimentation tank is about__________________?






15 to 30 cm/minute

127 - The water carriage system of collection of waste product________________?






requires treatment before disposal

128 - The working conditions in imhoff tanks are_______________?






anaerobic in lower compartment and aerobic in upper compartment

129 - Turbidity is measured on_______________?






standard silica scale

130 - When the balancing of the turbine is disturbed, we use ________






Emergency governing

131 - When there is no recirculation of sewage, then recirculation factor is_______________?






1

132 - Which of the following chemical compounds can be used for dechlorination of water ?






sulphur dioxide

133 - Which of the following compounds is widely used for algae control ?






copper sulphate

134 - Which of the following is not a water borne disease ?






maleria

135 - Which of the following methods of analysis of water distribution system is most suitable for long and narrow pipe system ?






equivalent pipe method

136 - Which of the following retards the self purification of stream ?






none of the above

137 - Which of the following sewers is preferred for combined system of sewage ?






egg shaped sewer

138 - Which of the following unit works in anaerobic conditions ?






sludge digestion tank

139 - Which of the following values of pH represents a stronger acid?






2

140 - With the increase in load, Energy in the turbine ________






Decreases

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