Environmental Engineering MCQ Questions and Answers in Civil Engineering

Question. As compared to geometrical increase method of forecasting population, arithmetical increase method gives
(a) Lesser value
(b) Higher value
(c) Same value
(d) Accurate value

Answer : A

Question. The rate of Alteration of pressure filters is
(a) Less than that of slow sand filters
(b) In between the filtration rate of slow sand filters and rapid sand filters
(c) Greater than that of rapid sand filters
(d) Equal to that of slow sand filters

Answer : C

Question. The minimum and maximum diameters of sewers shall preferably be
(a) 15 cm and 100 cm
(b) 15 cm and 300 cm
(c) 30 cm and 450 cm
(d) 60 cm and 300 cm

Answer : B

Question. In a BOD test, 1.0 ml of raw sewage was diluted to 100 ml and the dissolved oxygen concentration of diluted sample at the beginning was 6 ppm and it was 4 ppm at the end of 5 day incubation at 20°(c) The BOD of raw sewage will be
(a) 100 ppm
(b) 200 ppm
(c) 300 ppm
(d) 400 ppm

Answer : B

Question. As compared to shallow wells, deep wells have
(a) More depth
(b) Less depth
(c) More discharge
(d) Less discharge

Answer : C

Question. For satisfactory working of a sludge digestion unit, the pH range of digested sludge should be maintained as
(a) 4.5 to 6.0
(b) 6.5 to 8.0
(c) 8.5 to 10.0
(d) 10.5 to 12.0

Answer : B

Question. The percentage of filtered water, which is used for backwashing in rapid sand filters, is about
(a) 0.2 to 0.4
(b) 0.4 to 1.0
(c) 2 to 4
(d) 5 to 7

Answer : C

Question. The length of rectangular sedimentation tank should not be more than (Where ‘B’ is the width of the tank)
(a) B
(b) 2B
(c) 4B
(d) 8B

Answer : C

Question. The phenolic compounds in public water supply should not be more than
(a) 0.1 ppm
(b) 0.01 ppm
(c) 0.001 ppm
(d) 0.0001 ppm

Answer : C

Question. The amount of residual chlorine left in public water supply for safety against pathogenic bacteria is about
(a) 0.01 to 0.05 ppm
(b) 0.05 to 0.5 pp
(c) 0.5 to 1.0 ppm
(d) 1.0 to 5.0 ppm

Answer : B

Question. Cleaning is done by
(i) Scraping and removal in filters slow sand
(ii) Back washing in slow sand filters
(iii) Scraping and removal in filters rapid sand
(iv) Back washing in rapid sand filters
The correct answer is
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i) and (iv)
(d) (ii) and (iv)

Answer : C

Question. The dissolved oxygen level in natural unpolluted waters at normal temperature is found to be of the order of
(a) 1 mg/liter
(b) 10 mg/liter
(c) 100 mg/liter
(d) 1000 mg/liter

Answer : B

Question. The rate of BOD exerted at any time is
(a) Directly proportional to BOD satisfied
(b) Directly proportional to BOD remaining
(c) Inversely proportional to BOD satisfied
(d) Inversely proportional to BOD remaining

Answer : B

Question. A pipe which is installed in the house drainage to preserve the water seal of traps is called
(a) Vent pipe
(b) Anti-siphonage pipe
(c) Waste pipe
(d) Soil pipe

Answer : B

Question. The biochemical treatment of sewage effluents is essentially a process of
(a) Oxidation
(b) Dehydration
(c) Reduction
(d) Alkalinization

Answer : A

Question. The hourly variation factor is usually taken as
(a) 1.5
(b) 1.8
(c) 2.0
(d) 2.7

Answer : A

Question. The distribution mains are designed for
(a) Maximum daily demand
(b) Maximum hourly demand
(c) Average daily demand
(d) Maximum hourly demand on maximum day

Answer : D

Question. The self cleansing velocity for all sewers in India is usually
(a) Less than 1.0 m/sec
(b) 1.0 m/sec to 1.2 m/sec
(c) 1.5 m/sec to 2.0 m/sec
(d) 3.0 m/sec to 3.5 m/sec

Answer : B

Question. The most common cause of acidity in water is
(a) Carbon dioxide
(b) Oxygen
(c) Hydrogen
(d) Nitrogen

Answer : A

Question. In chlorination, with the rise in temperature of water, death rate of bacteria
(a) Increases
(b) Decreases
(c) Remains unaffected
(d) None of the above

Answer : A

Question. As compared to rapid sand filters, slow sand filters give
(i) Slower filtration rate
(ii) Higher filtration rate
(iii) Lesser efficiency in removal of bacteria
(iv) Higher efficiency in removal of bacteria
The correct answer is
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i) and (iv)
(d) (ii) and (iv)

Answer : C

Question. Facultative bacteria are able to work in
(a) Presence of oxygen only
(b) Absence of oxygen only
(c) Presence as well as in absence of oxygen
(d) Presence of water

Answer : C

Question. If the coli form bacteria is present in a sample of water, then the coli-form test to be conducted is
(i) Presumptive coli-form test
(ii) Confirmed coli-form test
(iii) Completed coli-form test
(a) Only (i)
(b) Both (i) and (ii)
(c) Both (i) and (iii)
(d) All (i), (ii) and (iii)

Answer : D

Question. Select the correct relationship between porosity (N), specific yield (y) and specific retention (R)
(a) N = y + R
(b) y = N + R
(c) R = N + y
(d) R > (N + y)

Answer : A

Question. Activated carbon is used for
(a) Disinfection
(b) Removing hardness
(c) Removing odours
(d) Removing corrosiveness

Answer : C

Question. As compared to cast iron pipes, steel pipes are
(a) Heavier
(b) Stronger
(c) Costlier
(d) Less susceptible to corrosion

Answer : B

Question. Period of cleaning of slow sand filters is about
(a) 24 - 48 hours
(b) 10 - 12 days
(c) 2 - 3 months
(d) 1 - 2 year

Answer : C

Question. Dissolved oxygen in streams is
(a) Maximum at noon
(b) Minimum at noon
(c) Maximum at midnight
(d) Same throughout the day

Answer : A

Question. The method of analysis of distribution system in which the domestic supply is neglected and fire demand is considered is
(a) Circle method
(b) Equivalent pipe method
(c) Electrical analysis method
(d) Hardy cross method

Answer : A

Question. Most suitable section of sewer in separate sewage system is
(a) Rectangular section
(b) Circular section
(c) Standard form of egg shaped sewer
(d) Modified egg shaped section

Answer : B

Question. The maximum permissible limit for fluoride in drinking water is
(a) 0.1 mg/liter
(b) 1.5 mg/liter
(c) 5 mg/liter
(d) 10 mg/liter

Answer : B

Question. Percentage of bacterial load that can be removed from water by the process of plain sedimentation is about
(a) 10 to 25
(b) 50
(c) 75
(d) 100

Answer : C

Question. The maximum efficiency of BOD removal is achieved in
(a) Oxidation pond
(b) Oxidation ditch
(c) Aerated lagoons
(d) Trickling filters

Answer : B

Question. Disinfection of water results in
(a) Removal of turbidity
(b) Removal of hardness
(c) Killing of disease bacteria
(d) Complete sterilisation

Answer : C

Question. Which of the following values of pH represents a stronger acid?
(a) 2
(b) 5
(c) 7
(d) 10

Answer : A

Question. The percentage of chlorine in fresh bleaching powder is about
(a) 10 to 15
(b) 20 to 25
(c) 30 to 35
(d) 40 to 50

Answer : C

Question. Septic tank is a
(i) Settling tank
(ii) Digestion tank
(iii) Aeration tank
(a) Only (i)
(b) (i) and (ii)
(c) (i) and (iii)
(d) Only (iii)

Answer : B

Question. An egg shaped section of sewer
(a) Is economical than circular section
(b) Provides self cleansing velocity at low discharges
(c) Is more stable than circular section
(d) Is easy to construct

Answer : B

Question. The minimum dissolved oxygen which should always be present in water in order to save the aquatic life is
(a) 1 ppm
(b) 4 ppm
(c) 10 ppm
(d) 40 ppm

Answer : B

Question. The type of sewer which is suitable for both combined and separate system is
(a) Circular sewer
(b) Egg shaped sewer
(c) Horseshoe type sewer
(d) Semi-elliptical sewer

Answer : B

Question. Sewerage system is usually designed for
(a) 10 years
(b) 25 years
(c) 50 years
(d) 75 years

Answer : B

Question. If the total hardness of water is greater than its total alkalinity, the carbonate hardness will be equal to
(a) Total alkalinity
(b) Total hardness
(c) Total hardness total alkalinity
(d) Non carbonate hardness

Answer : A

Question. The pathogens can be killed by
(a) Nitrification
(b) Chlorination
(c) Oxidation
(d) None of the above

Answer : B

Question. If the time of concentration is 9 minutes, then the intensity of rainfall according to British Ministry of Health formula will be
(a) 4 mm/hr
(b) 10 mm/hr
(c) 20 mm/hr
(d) 40 mm/hr

Answer : D

Question. The water carriage system of collection of waste product
(a) Is cheaper in initial cost than dry conservancy system
(b) Requires treatment before disposal
(c) Creates hygienic problem
(d) All of the above

Answer : B

Question. Sludge volume index is defined as the ratio of
(a) Percentage of sludge by volume to percentage of suspended solids by weight
(b) Percentage of sludge by volume to percentage of total solids by weight
(c) Percentage of suspended solids by weight to percentage of sludge by volume
(d) Percentage of total solids by weight to percentage of sludge by volume

Answer : A

Question. Which of the following is not a water borne disease?
(a) Dysentery
(b) Cholera
(c) Typhoid
(d) Malaria

Answer : D

Question. The polluted water is one which
(a) Contains pathogenic bacteria
(b) Consists of undesirable substances rendering it unfit for drinking and domestic use
(c) Is safe and suitable for drinking and domestic use
(d) Is contaminated

Answer : B

Question. In facultative stabilization pond, the sewage is treated by
(a) Aerobic bacteria only
(b) Algae only
(c) Dual action of aerobic bacteria and anaerobic bacteria
(d) Sedimentation

Answer : C

Question. For a country like India, where rainfall is mainly confined to one season, the suitable sewerage system will be
(a) Separate system
(b) Combined system
(c) Partially combined system
(d) Partially separate system

Answer : A

Question. The means of access for inspection and cleaning of sewer line is known as
(a) Inlet
(b) Manhole
(c) Drop manhole
(d) Catch basin

Answer : B

Question. The amount of coagulant needed for coagulation of water increases with
(i) Increase in turbidity of water
(ii) Decrease in turbidity of water
(iii) Increase in temperature of water
(iv) Decrease in temperature of water
The correct answer is
(a) (i) and (ii)
(b) (i) and (iv)
(c) (ii) and (iii)
(d) (ii) and (iv)

Answer : B

Question. The type of valve which allows water to flow in one direction but prevents its flow in the reverse direction is
(a) Reflux valve
(b) Sluice valve
(c) Air relief valve
(d) Pressure relief valve

Answer : A

Question. Standard EDTA (ethylene diamine tetra acetic acid) solution is used to determine the
(a) Hardness in water
(b) Turbidity in water
(c) Dissolved oxygen in water
(d) Residual chlorine in water

Answer : A

Question. Orthotolidine test is used for determination of
(a) Dissolved oxygen
(b) Residual chlorine
(c) Biochemical oxygen demand
(d) Dose of coagulant

Answer : B

Question. Double filtration is used
(a) To increase the filtration slow sand filters capacity of
(b) To increase the filtration rapid sand filters capacity of
(c) For isolated buildings like pools, hotels etc swimming
(d) All of the above

Answer : A

Question. Which of the following retards the self purification of stream?
(a) Higher temperature
(b) Sunlight
(c) Satisfying oxygen demand
(d) None of the above

Answer : D

Question. The gas from sludge digestion tank is mainly composed of
(a) Nitrogen
(b) Carbon dioxide
(c) Hydrogen sulphide
(d) Methane

Answer : D

Question. Laying of sewers is usually done with the help of
(a) A Theodolite
(b) A compass
(c) Sight rails and boning rods
(d) A plane table

Answer : C

Question. In water treatment, rapid gravity filters are adopted to remove
(a) Dissolved organic substances
(b) Dissolved solids and dissolved gases
(c) Floating solids and dissolved inorganic solids
(d) Bacteria and colloidal solids

Answer : D

Question. The working conditions in imhoff tanks are
(a) Aerobic only
(b) Anaerobic only
(c) Aerobic in lower compartment and anaerobic in upper compartment
(d) Anaerobic in lower compartment and aerobic in upper compartment

Answer : D

Question. Generally the detention period for grit chambers is kept as
(a) 1 minute
(b) 5 minutes
(c) 24 hours
(d) 12 hours

Answer : A

Question. The correct relation between theoretical oxygen demand (TOD), Biochemical oxygen demand (BOD) and Chemical oxygen demand (COD) is given by
(a) TOD > BOD > COD
(b) TOD > COD > BOD
(c) BOD > COD > TOD
(d) COD > BOD > TOD

Answer : B

Question. Sewage treatment units are designed for
(a) Maximum flow only
(b) Minimum flow only
(c) Average flow only
(d) Maximum and minimum flow

Answer : C

Question. The rate of filtration in slow sand filters in million litres per day per hectare is about
(a) 50 to 60
(b) 100 to 150
(c) 500 to 600
(d) 1400 to 1500

Answer : A

Question. Sewage treatment units are normally designed for
(a) 5 - 10 years
(b) 15 - 20 years
(c) 30 - 40 years
(d) 40 - 50 years

Answer : B

Question. For normal sludge, the value of sludge index for Indian conditions is
(a) 0 to 50
(b) 50 to 150
(c) 150 to 350
(d) 350 to 500

Answer : C 

Question. Residual chlorine in water is determined by
(a) Starch iodide method
(b) Orthotolidine method
(c) Both (A) and (B)
(d) None of the above

Answer : C

Question. The characteristics of fresh and septic sewage respectively are
(a) Acidic and alkaline
(b) Alkaline and acidic
(c) Both acidic
(d) Both alkaline

Answer : B

Question. A sewer that receives the discharge of a number of house sewers is called
(a) House sewer
(b) Lateral sewer
(c) Intercepting sewer
(d) Sub-main sewer

Answer : B