Waste Water Engineering MCQs

Option A: The process of decomposing the organic matter under controlled anaerobic conditions, is called sludge digestion

Option B: Sludge digestion is carried out in sludge tank

Option C: The gases produced in sludge digestion process, contain 75% carbon dioxide

Option D: The gases produced in sludge digestion process, contain 75% methane

Correct Answer: The gases produced in sludge digestion process, contain 75% carbon dioxide ✔

Option A: The mixture of water and waste products, is called sewage

Option B: The treated sewage effluents, are generally used for irrigating the crops

Option C: The process of collecting, treating and disposing off the sewage, is called sewerage

Option D: The old convergence system was definitely better than water carried sewerage system

Correct Answer: The old convergence system was definitely better than water carried sewerage system ✔

Option A: Anaerobic bacteria flourish in the absence of oxygen

Option B: Aerobic bacteria flourish in the presence of oxygen

Option C: Facultative bacteria flourish with or without oxygen

Option D: All the above

Correct Answer: All the above ✔

Option A: The circular section of sewers provides maximum hydraulic mean depth

Option B: The circular sewers are provided for separate sewerage system

Option C: The circular sewers work efficiently if the sections run at least half full

Option D: All the above

Correct Answer: All the above ✔

Option A: Inlets are provided on the road surface at the lowest point for draining rain water

Option B: Inlets are generally provided at an interval of 30 m to 60 m along straight roads

Option C: Inlets having horizontal openings, are called horizontal inlets

Option D: All the above

Correct Answer: All the above ✔

Option A: Indore method of composting involves decomposition under aerobic conditions

Option B: Bangalore method of composting involves decomposing under anaerobic conditions

Option C: Fully stabilised refuse by the Bangalore method of compositing is a powdery mass called humus

Option D: all of these

Correct Answer: all of these ✔

Option A: pH value indicates acidity and alkalinity of sewage

Option B: In acidic sewage, the pH value is less than 7

Option C: In alkaline sewage, the pH value is more than 7

Option D: All the above

Correct Answer: All the above ✔

Option A: The boning rod is used for checking the levels of the sewer inverts

Option B: Manhole covers are made circular for the convenience of the cleaning staff

Option C: A manhole is classified as shallow manhole if its depth is less than 0.9 m

Option D: All the above

Correct Answer: All the above ✔

Option A: Turbidity is more in strong sewage

Option B: The black colour indicates septic sewage

Option C: The sewage omits offensive odours after four hours

Option D: All the above

Correct Answer: All the above ✔

Option A: A heap

Option B: Plateau

Option C: Windrow

Option D: None of these

Correct Answer: None of these ✔

Option A: Carbondioxide

Option B: Methane

Option C: Ammonia

Option D: Carbon monoxide

Correct Answer: Methane ✔

Option A: Over flow rate

Option B: Surface loading

Option C: Over flow velocity

Option D: All the above

Correct Answer: All the above ✔

Option A: 30 minutes

Option B: 1 hour

Option C: 1 hour and 30 minutes

Option D: 2 hours

Correct Answer: 2 hours ✔

Option A: The particular manhole and one manhole on upstream and one manhole on downstream should remain open for 30 minutes

Option B: Proper tests for the presence of poisonous gases must be carried out

Option C: The men entering the manhole should be advised to smoke in the sewer

Option D: Warning signals should be erected

Correct Answer: The men entering the manhole should be advised to smoke in the sewer ✔

Option A: 0.50 m/sec

Option B: 0.60 m/sec

Option C: 0.70 m/sec

Option D: 0.75 m/sec

Correct Answer: 0.75 m/sec ✔

Option A: 25,000 to 35,000 litres/sqm/day

Option B: 40,000 to 50,000 litres/sqm/day

Option C: 50,000 to 60,000 litres/sqm/day

Option D: 80,000 to 100,000 litres/sqm/day

Correct Answer: 50,000 to 60,000 litres/sqm/day ✔

Option A: Top of smaller sewer is kept lower

Option B: Top of larger sewer is kept lower

Option C: Tops of both the sewers are at the same level

Option D: None of these

Correct Answer: None of these ✔

Option A: Unexpected large scale infiltration of stream water

Option B: Unexpected increase in the population

Option C: Under estimates of maximum and average flows

Option D: All of the above

Correct Answer: All of the above ✔

Option A: Main sewer

Option B: Outfall sewer

Option C: Branch sewer

Option D: House sewer

Correct Answer: Outfall sewer ✔

Option A: 16 m

Option B: 20 m

Option C: 24 m

Option D: 30 m

Correct Answer: 24 m ✔

Option A: Q = [(4 + )/(18 + )] q

Option B: Q = [(18 + P)/(4 + )] q

Option C: Q = [(18 + )/(4 + )] q

Option D: Q = [(5 + )/((15 + )] q

Correct Answer: Q = [(18 + )/(4 + )] q ✔

Option A: /2

Option B: /4

Option C: /3

Option D: D

Correct Answer: /3 ✔

Option A: Hydrogen sulphide

Option B: Carbon dioxide

Option C: Methane

Option D: Oxygen

Correct Answer: Carbon dioxide ✔

Option A: Imhoff tanks

Option B: Trickling filters

Option C: Sludge sedimentation tanks

Option D: None of these

Correct Answer: Trickling filters ✔

Option A: 1 in 60

Option B: 1 in 100

Option C: 1 in 120

Option D: None of these

Correct Answer: 1 in 100 ✔

Option A: Raising low lying areas by dumping

Option B: Concreting

Option C: Both A. and B.

Option D: Neither A. nor B

Correct Answer: Concreting ✔

Option A: Total organic solids

Option B: Total solids

Option C: Total in organic solids

Option D: Settleable solids

Correct Answer: Settleable solids ✔

Option A: When sewage is fresh

Option B: When diluting water has high dissolved oxygen content

Option C: When diluting water is used for water supply near the point of sewage disposed

Option D: When the diluting water is having flow currents

Correct Answer: When diluting water is used for water supply near the point of sewage disposed ✔

Option A: 1 in 100 upward

Option B: 1 in 500 upward

Option C: 1 in 100 downward

Option D: 1 in 503 upward

Correct Answer: 1 in 100 downward ✔

Option A: H2SO4

Option B: HNO3

Option C: HCl

Option D: None of these

Correct Answer: H2SO4 ✔

Option A: More than the self-cleansing velocity

Option B: Less than the self-cleansing velocity

Option C: Less than 10 m/sec

Option D: More than 20 m/sec

Correct Answer: Less than the self-cleansing velocity ✔

Option A: Top side

Option B: Bottom side

Option C: Horizontal side

Option D: All sides

Correct Answer: Bottom side ✔

Option A: Distances 150 m to 300 m

Option B: Upper ends of branch sewers

Option C: Every change in the size of sewers

Option D: All the above

Correct Answer: All the above ✔

Option A: Q/(B × D)

Option B: Q/(L × D)

Option C: Q/L

Option D: Q/(B × L)

Correct Answer: Q/(B × L) ✔

Option A: Bio-Chemical Oxygen Demand (B.O.D.)

Option B: Dissolved Oxygen (D.O.)

Option C: Chemical Oxygen Demand (C.O.D.)

Option D: None of these

Correct Answer: Dissolved Oxygen (D.O.) ✔

Option A: 90 %

Option B: 95 %

Option C: 99 %

Option D: 9.9 %

Correct Answer: 9.9 % ✔

Option A: Parabolic

Option B: Circular

Option C: Rectangular

Option D: New egged

Correct Answer: Circular ✔

Option A: Hydrology

Option B: Dissolved oxygen in water

Option C: Temperature

Option D: All the above

Correct Answer: All the above ✔

Option A: 45 %

Option B: 50 %

Option C: 55 %

Option D: 60 %

Correct Answer: 55 % ✔

Option A: Imhoff Cone

Option B: Turbid meter

Option C: Potentiometer

Option D: None of these

Correct Answer: Potentiometer ✔

Option A: 25,000 to 35,000 litres/sqm/day

Option B: 40,000 to 50,000 litres/sqm/day

Option C: 50,000 to 60,000 litres/sqm/day

Option D: 80,000 to 100,000 litres/sqm/day

Correct Answer: 40,000 to 50,000 litres/sqm/day ✔

Option A: A gap of 7.5 cm between the bottom of the covering slab and the top level of scum is provided

Option B: The outlet invert level is kept 5 to 7.5 cm below the inlet invert level

Option C: The minimum width of septic level is 90 cm

Option D: The depth of tank is kept equal to its width

Correct Answer: The depth of tank is kept equal to its width ✔

Option A: Combined system

Option B: Partially separate system

Option C: Separate system

Option D: None of these

Correct Answer: Separate system ✔

Option A: Fertilizer

Option B: Building material

Option C: Chemical for lowering B.O.D.

Option D: Base material for paints

Correct Answer: Fertilizer ✔

Option A: Separate system

Option B: Combined system

Option C: Partially combined system

Option D: None of these

Correct Answer: Combined system ✔

Option A: 0°C

Option B: 15°C

Option C: 20°C

Option D: 25°C

Correct Answer: 0°C ✔

Option A: Manholes are provided in sewer pipes at suitable intervals

Option B: Catch basins are generally provided in sewers for carrying drainage discharge

Option C: Inlets are generally provided in all sewers

Option D: None of these

Correct Answer: Inlets are generally provided in all sewers ✔

Option A: 25 %

Option B: 50 %

Option C: 10 %

Option D: 5 %

Correct Answer: 50 % ✔

Option A: Initial demand

Option B: First stage demand

Option C: Carbonaceous demand

Option D: All of these

Correct Answer: All of these ✔

Option A: 1.250 D

Option B: 1.350 D

Option C: 1.425 D

Option D: 1.625 D

Correct Answer: 1.625 D ✔

Option A: A jar

Option B: A breaker

Option C: A test tube

Option D: An Imhoff cone

Correct Answer: An Imhoff cone ✔

Option A: 65 to 70%

Option B: 70 to 75%

Option C: 75 to 80%

Option D: 85%

Correct Answer: 75 to 80% ✔

Option A: Lower end of ventilating column

Option B: Upper end of ventilating column

Option C: Upper end of the manhole

Option D: First step in manhole

Correct Answer: Upper end of ventilating column ✔

Option A: A sewer drops from a height

Option B: A branch sewer joins the main sewer at higher level

Option C: A lamp is inserted to check obstruction

Option D: None of these

Correct Answer: A branch sewer joins the main sewer at higher level ✔

Option A: Comminutor

Option B: Shredder

Option C: Both A. and B.

Option D: Neither A. nor B.

Correct Answer: C. Both A. and B. ✔

Option A: Potassium permanganate

Option B: Sulphuric acid and napthamine

Option C: Phenol-di -sulphuric acid and potassium hydroxide

Option D: None of these

Correct Answer: Phenol-di -sulphuric acid and potassium hydroxide ✔

Option A: Free board of 0.3 m may be provided

Option B: The baffles or tees are extended up to top level of scum

Option C: The clear space between the baffle top and covering slab is about 7.5 cm

Option D: All the above

Correct Answer: All the above ✔

Option A: Highly resistant to sulphide corrosion

Option B: Highly impervious

Option C: Hydraulically efficient because of their smooth interior surface

Option D: Especially suited to pressure pipes

Correct Answer: Especially suited to pressure pipes ✔

Option A: 1.095

Option B: 1.085

Option C: 1.075

Option D: 1.065

Correct Answer: 1.095 ✔

Option A: Without entry ladders

Option B: Without manhole covers

Option C: With depths more than 3.5 m

Option D: Having drains at different levels

Correct Answer: Having drains at different levels ✔

Option A: 200 ppm

Option B: 225 ppm

Option C: 250 ppm

Option D: None of these

Correct Answer: 250 ppm ✔

Option A: Must be of adequate size to avoid over flow

Option B: Must flow under gravity ½ to ¾ full

Option C: Must be laid at least 2 to 3 m deep to collect /water from the basements

Option D: All the above

Correct Answer: All the above ✔

Option A: Mechanized receipt

Option B: Mechanized segregation

Option C: Mechanized pulverising of refuse

Option D: All of these

Correct Answer: All of these ✔

Option A: w r S S

Option B: w r1/2

Option C: w r S

Option D: w r2/3

Correct Answer: w r S S ✔

Option A: d² (0.011d + 0.785H)/Q

Option B: d (0.022d + 0.085H)/Q

Option C: d (0.785d + 0.011H)/Q

Option D: d (0.285d + 0.011H)/Q

Correct Answer: d² (0.011d + 0.785H)/Q ✔

Option A: At the end of septic tanks

Option B: On manholes

Option C: With a W.C. trap

Option D: At the beginning of sewer line

Correct Answer: C. With a W.C. trap ✔

Option A: More than 7

Option B: Less than 7

Option C: Less than 6

Option D: More than 6

Correct Answer: More than 7 ✔

Option A: 52.5 cm

Option B: 67.5 cm

Option C: 82.5 cm

Option D: None of these

Correct Answer: None of these ✔

Option A: Both A and R is true and R is the correct explanation of A

Option B: Both A and R is true but R is not a correct explanation of A

Option C: A is true but R is false

Option D: A is false but R is true

Correct Answer: Both A and R is true and R is the correct explanation of A ✔

Option A: Circular septic tanks

Option B: Rectangular septic tanks

Option C: Circular Imhoff double tanks with bottom hoppers

Option D: Circular Imhoff double storey tanks without bottom hoppers

Correct Answer: Circular Imhoff double storey tanks without bottom hoppers ✔

Option A: 100 mm dia.

Option B: 150 mm dia.

Option C: 225 mm dia.

Option D: All of these

Correct Answer: 225 mm dia. ✔

Option A: D’ = 0.64 D

Option B: D’ = 0.74 D

Option C: D’ = 0.84 D

Option D: D’ = 0.94 D

Correct Answer: D’ = 0.84 D ✔

Option A: The shape is rectangular

Option B: Detention period is 2 hours

Option C: The velocity of flow is restricted to 0.30 m/minute

Option D: All the above

Correct Answer: All the above ✔

Option A: 3 m

Option B: 3.5 m

Option C: 4 m

Option D: 4.5 m

Correct Answer: 3 m ✔

Option A: Weight of the pipe

Option B: Weight of the back fill

Option C: Superimposed traffic loads

Option D: All the above

Correct Answer: All the above ✔

Option A: Ammonia and nitrogen

Option B: Nitrogen and organic nitrogen

Option C: Organic nitrogen and ammonia

Option D: All the above

Correct Answer: All the above ✔

Option A: Liberation of ammonia-formation of nitrites-formation of nitrates-liberation of nitrogen

Option B: Liberation of nitrogen-liberation of ammonia-formation of nitrites- formation of nitrates

Option C: Liberation of nitrogen-formation of nitrates-formation of nitrites-liberation of ammonia

Option D: Formation of nitrates-formation of nitrites-liberation of nitrates-liberation of nitrates

Correct Answer: Liberation of ammonia-formation of nitrites-formation of nitrates-liberation of nitrogen ✔

Option A: 10 cm

Option B: 15 cm

Option C: 20 cm

Option D: 25 cm

Correct Answer: 15 cm ✔

Option A: The materials separated by screens, is called screenings

Option B: The screenings are disposed off either by burning or by burial or by dumping

Option C: The process of burning the screenings, is known as compositing

Option D: All the above

Correct Answer: All the above ✔

Option A: One pipe

Option B: Two pipes

Option C: Three pipes

Option D: Four pipes

Correct Answer: Three pipes ✔

Option A: Less than 0.01 mm

Option B: Less than 0.05 mm

Option C: Less than 0.1 mm

Option D: Greater than 0.1 mm

Correct Answer: Greater than 0.1 mm ✔

Option A: The bottom is silted

Option B: The bottom is scoured

Option C: Both silting and scouring occur at the bottom

Option D: Neither silting nor scouring occurs at the bottom

Correct Answer: Neither silting nor scouring occurs at the bottom ✔

Option A: 2 to 3 mm

Option B: 3 to 5 mm

Option C: 5 to 8 mm

Option D: 8 to 10 mm

Correct Answer: 2 to 3 mm ✔

Option A: 10 litres

Option B: 15 litres

Option C: 20 litres

Option D: 25 litres

Correct Answer: 20 litres ✔

Option A: Is only provided

Option B: Is doubled

Option C: Is trebled

Option D: Is not enough

Correct Answer: Is doubled ✔

Option A: 0.05 m/sec

Option B: 0.09 m/sec

Option C: 1.25 m/sec

Option D: None of these

Correct Answer: 0.09 m/sec ✔

Option A: Domestic sewage

Option B: Industrial sewage

Option C: Storm sewage

Option D: All the above

Correct Answer: All the above ✔

Option A: Horizontally

Option B: Vertically

Option C: At an angle of 30°

Option D: At an angle of 60°

Correct Answer: Vertically ✔

Option A: Carbondioxide gas

Option B: Hydrogen sulphide gas

Option C: Methane gas

Option D: Petrol vapours

Correct Answer: Methane gas ✔

Option A: 50 mg/l

Option B: 100 mg/l

Option C: 150 mg/l

Option D: 250 mg/l

Correct Answer: 50 mg/l ✔

Option A: It is cheaper in construction

Option B: It provides maximum area for a given perimeter

Option C: It provides maximum hydraulic mean depth

Option D: All the above

Correct Answer: All the above ✔

Option A: 5

Option B: 10

Option C: 15

Option D: 20

Correct Answer: 20 ✔

Option A: Water test is carried out to check water tightness of the joints

Option B: Test for straightness is carried out with the help of a lamp and mirror

Option C: Obstruction test is carried out with the help of smooth ball of diameter 13 mm

Option D: All the above

Correct Answer: All the above ✔

Option A: 0.4 to 0.5 m

Option B: 0.5 to 0.7 m

Option C: 0.7 to 0.9 m

Option D: 0.9 to 1.20 m

Correct Answer: 0.7 to 0.9 m ✔

Option A: Are used for carrying sewage and drainage from houses

Option B: Are manufactured from clays and shale

Option C: After casting are dried and burnt at temperature 150°C, 700°C and 1200°C

Option D: All the above

Correct Answer: All the above ✔

Option A: Parabolic

Option B: Circular

Option C: Rectangular

Option D: New egged

Correct Answer: Circular ✔

Option A: Standard egg shaped

Option B: Circular shaped

Option C: Horse shoe shaped

Option D: Parabolic shaped

Correct Answer: Horse shoe shaped ✔

Option A: Glazed bricks sewers

Option B: Cast iron sewers

Option C: Cement concrete sewers

Option D: Stone ware sewers

Correct Answer: Glazed bricks sewers ✔

Option A: Degradation

Option B: Active decomposition

Option C: Recovery

Option D: Cleaner water

Correct Answer: Active decomposition ✔

Option A: Circular

Option B: Egg shaped

Option C: Rectangular

Option D: Horse shoe shaped

Correct Answer: Egg shaped ✔