If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is
If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is
The sewage treatment in septic tanks is due to
The sewage treatment in septic tanks is due to
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
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
The layers of vegetable wastes and night soil alternatively piled above the ground to form a mound, is called
The layers of vegetable wastes and night soil alternatively piled above the ground to form a mound, is called
In a grit chamber of a sewage treatment plant,
In a grit chamber of a sewage treatment plant,
The porosity of sediments in sewer pipes, is usually taken as
The porosity of sediments in sewer pipes, is usually taken as
For trunk sewers more than 1.25 m in diameter, the ratio of the maximum daily sewage flow to the average daily sewage flow is assumed
For trunk sewers more than 1.25 m in diameter, the ratio of the maximum daily sewage flow to the average daily sewage flow is assumed
The suitable cross-section of sewers to carry combined flow, is
The suitable cross-section of sewers to carry combined flow, is
The quantity of liquid waste which flows in sewers during the period of rainfall, is known
The quantity of liquid waste which flows in sewers during the period of rainfall, is known
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
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
The asbestos cement sewers are
The asbestos cement sewers are
Which one of the following statements regarding septic tanks is wrong?
Which one of the following statements regarding septic tanks is wrong?
In sewers designed with self cleansing velocity,
In sewers designed with self cleansing velocity,
Large diameter sewers subjected to external pressure alone, are reinforced
Large diameter sewers subjected to external pressure alone, are reinforced
The minimum diameter of sewer to be adopted is
The minimum diameter of sewer to be adopted is
The disintegrating pump in which solid matter is broken up before passing out, is
The disintegrating pump in which solid matter is broken up before passing out, is
In very first stage of decomposition of the organic matter in sewage
In very first stage of decomposition of the organic matter in sewage
The first stage of neutral process of sludge digestion, is
The first stage of neutral process of sludge digestion, is
The effluent of a septic tank is
The effluent of a septic tank is
The discharge per unit plan area of a sedimentation tank, is generally called
The discharge per unit plan area of a sedimentation tank, is generally called
Discrete or granular particles change their
Discrete or granular particles change their
In normal conditions, the period for sludge digestion, is
In normal conditions, the period for sludge digestion, is
The sewer pipe which carries sewage from a building for immediate disposal is
The sewer pipe which carries sewage from a building for immediate disposal is
If is the rugosity coefficient, is the bed slope of sewer, the velocity of flow in m/sec may be obtained by the formula V = (1/n) r2/3 s1/2 evolved by
If is the rugosity coefficient, is the bed slope of sewer, the velocity of flow in m/sec may be obtained by the formula V = (1/n) r2/3 s1/2 evolved by
A sewer pipe contains 1 mm sand particles of specific gravity 2.65 and 5 mm organic particles of specific gravity 1.2, the minimum velocity required for removing the sewerage, is
A sewer pipe contains 1 mm sand particles of specific gravity 2.65 and 5 mm organic particles of specific gravity 1.2, the minimum velocity required for removing the sewerage, is
The rainfall at any place may be determined by
The rainfall at any place may be determined by
Dry weather flow is:
Dry weather flow is:
The maximum spacing of manholes specified by Indian standard in sewers upto 0.3 m diameter is
The maximum spacing of manholes specified by Indian standard in sewers upto 0.3 m diameter is
If D.O. concentration falls down to zero in any natural drainage, it indicates the zone of
If D.O. concentration falls down to zero in any natural drainage, it indicates the zone of
Dilution method of disposing of sewage, is not preferred to
Dilution method of disposing of sewage, is not preferred to
The flow velocity in detritus tanks is
The flow velocity in detritus tanks is
Sewer pipes are designed for maximum discharge with 25% to 33% vacant cross-sectional area for
Sewer pipes are designed for maximum discharge with 25% to 33% vacant cross-sectional area for
The bottom of the sewage inlet chamber of septic tanks, is provided an outward slope
The bottom of the sewage inlet chamber of septic tanks, is provided an outward slope
Drop manholes at the junctions of sewer lines, are provided if
Drop manholes at the junctions of sewer lines, are provided if
Maximum permissible velocity 1.5 m/sec, is adopted in drains
Maximum permissible velocity 1.5 m/sec, is adopted in drains
The value of Chezy’s constant C = 157.6/(1.81 + K/ ) is used in
The value of Chezy’s constant C = 157.6/(1.81 + K/ ) is used in
The drainage area of a town is 12 hectares. Its 40% area is hard pavement ( K = 0.85), the 40% area is unpaved streets (K = 0.20) and the remaining is wooded areas (K = 0.15). Assuming the time of concentration for the areas as 30 minutes and using the formula Ps = 900/(t + 60) the maximum run off is
The drainage area of a town is 12 hectares. Its 40% area is hard pavement ( K = 0.85), the 40% area is unpaved streets (K = 0.20) and the remaining is wooded areas (K = 0.15). Assuming the time of concentration for the areas as 30 minutes and using the formula Ps = 900/(t + 60) the maximum run off is
Drop manholes are the manholes
Drop manholes are the manholes
In R.C. sewer pipes, the percentage longitudinal reinforcement to the cross-sectional area of concrete is kept
In R.C. sewer pipes, the percentage longitudinal reinforcement to the cross-sectional area of concrete is kept
15 cumecs, the depth d and width are related by For drains up to
15 cumecs, the depth d and width are related by For drains up to
5 days-biochemical oxygen demand (BOD5) is taken at a temperature of
5 days-biochemical oxygen demand (BOD5) is taken at a temperature of
In case of Imhoff tanks,
In case of Imhoff tanks,
A manhole is classified as shallow if its depth is between
A manhole is classified as shallow if its depth is between
In a sedimentation tank (length L, width B, depth D) the settling velocity of a particle for a discharge Q, is
In a sedimentation tank (length L, width B, depth D) the settling velocity of a particle for a discharge Q, is
In a residential colony, sewers of diameters 100 mm, 150 mm and 225 mm were laid with a gradient 1 in 120. Which portion of the sewage system does not choke in due course of time?
In a residential colony, sewers of diameters 100 mm, 150 mm and 225 mm were laid with a gradient 1 in 120. Which portion of the sewage system does not choke in due course of time?
Aerobic bacterias
Aerobic bacterias
Lead caulked joints are used for laying
Lead caulked joints are used for laying
Pick up the correct statement from the following:
Pick up the correct statement from the following:
The sewage treatment units in which anaerobic decomposition of organic matter is used, are called
The sewage treatment units in which anaerobic decomposition of organic matter is used, are called
Acid regression stage of sludge digestion at a temperature 21°C extends over a period of
Acid regression stage of sludge digestion at a temperature 21°C extends over a period of
If the grit in grit chambers is 4.5 million litres per day, its cleaning is done
If the grit in grit chambers is 4.5 million litres per day, its cleaning is done
If the discharge of a sewer running half is 628 1.p.s., i = 0.001, and n = 0.010, the diameter of the sewer, is
If the discharge of a sewer running half is 628 1.p.s., i = 0.001, and n = 0.010, the diameter of the sewer, is
If the side of a square sewer is 1000 mm, the diameter of a hydraulically equivalent circular section, is
If the side of a square sewer is 1000 mm, the diameter of a hydraulically equivalent circular section, is
The presence of free ammonia in sewage, is detected by
The presence of free ammonia in sewage, is detected by
Clogging of sewers, is caused due to
Clogging of sewers, is caused due to
In trickling filter, B.O.D. is reduced to
In trickling filter, B.O.D. is reduced to
Hume steel pipes are
Hume steel pipes are
A cylindrical ejector having its height 2 m fills after every 10 minutes with a peak sewage discharge of 0.0157 cumec. The diameter of the ejector chamber, is
A cylindrical ejector having its height 2 m fills after every 10 minutes with a peak sewage discharge of 0.0157 cumec. The diameter of the ejector chamber, is
Are available in size Stoneware sewers
Are available in size Stoneware sewers
hydraulically equivalent, the relationship which holds good, is
hydraulically equivalent, the relationship which holds good, is
For a continuous flow type of sedimentation tanks
For a continuous flow type of sedimentation tanks
The spacing of man holes along a straight portion of a sewer is 300 m, the diameter of the sewer may be
The spacing of man holes along a straight portion of a sewer is 300 m, the diameter of the sewer may be
If D is the diameter of a circular sewer and D’ is the top horizontal diameter of an equivalent egg shaped section, the relationship which holds good, is
If D is the diameter of a circular sewer and D’ is the top horizontal diameter of an equivalent egg shaped section, the relationship which holds good, is
Dried sewage after treatment is used as
Dried sewage after treatment is used as
In a sludge digestion tank if the moisture content of sludge V1 litres is reduced from p1 % to p2 % the volume V2 is
In a sludge digestion tank if the moisture content of sludge V1 litres is reduced from p1 % to p2 % the volume V2 is
The pH value of sewage is determined with the help of
The pH value of sewage is determined with the help of
Facultative bacteria survive in
Facultative bacteria survive in
The clarigesters are
The clarigesters are
Pick up the correct statement from the following:
Pick up the correct statement from the following:
Flocculated particles do not change their
Flocculated particles do not change their
It is customary to design a sewer for D.W.F. on the basis of
It is customary to design a sewer for D.W.F. on the basis of
A manhole is generally provided at each
A manhole is generally provided at each
The standard B.O.D. of water is taken for
The standard B.O.D. of water is taken for
In a trickling filter
In a trickling filter
The sewer which transports the sewage to the point of treatment, is called
The sewer which transports the sewage to the point of treatment, is called
The drop man holes are generally provided in sewers for
The drop man holes are generally provided in sewers for
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
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
For non-scouring velocity 5 m/sec, the type of sewers generally preferred to, is
For non-scouring velocity 5 m/sec, the type of sewers generally preferred to, is
Oxidation process results in the formation of
Oxidation process results in the formation of
The recommended detention period for grit chambers is
The recommended detention period for grit chambers is
For laying a sewer line in a trench of 2 m width, an offset line is marked on the ground parallel to the given centre line at a distance of
For laying a sewer line in a trench of 2 m width, an offset line is marked on the ground parallel to the given centre line at a distance of
The width of a settling tank with 2 hour detention period for treating sewage 378 cu m per hour, is
The width of a settling tank with 2 hour detention period for treating sewage 378 cu m per hour, is
The sewer that unloads the sewage at the point of treatment is called
The sewer that unloads the sewage at the point of treatment is called
The sludge does not contain waste water from
The sludge does not contain waste water from
Removal of oil and grease from sewage, is known
Removal of oil and grease from sewage, is known
The temperature affects the
The temperature affects the
For design of sewers, percentage of sewage discharge is assumed
For design of sewers, percentage of sewage discharge is assumed
The rational formula for peak drainage discharge, was evolved by
The rational formula for peak drainage discharge, was evolved by
R.M.O. expenses include
R.M.O. expenses include
A rainfall may be classified as acidic if its pH value is less or equal to
A rainfall may be classified as acidic if its pH value is less or equal to
A nuisance is experienced in diluting water if dilution factor is less than
A nuisance is experienced in diluting water if dilution factor is less than
Which one of the following gases is most significant as air pollutant?
Which one of the following gases is most significant as air pollutant?
For sewer mains of 0.5 to 1 m diameter, the ratio of maximum daily sewage flow to the average daily sewage flow is assumed
For sewer mains of 0.5 to 1 m diameter, the ratio of maximum daily sewage flow to the average daily sewage flow is assumed
If the depletion of oxygen is found to be 5 ppm after incubating a 2.5% solution of sewage sample for 5 days at 21°C, B.O.D. of the sewage is
If the depletion of oxygen is found to be 5 ppm after incubating a 2.5% solution of sewage sample for 5 days at 21°C, B.O.D. of the sewage is
If 2% solution of a sewage sample is incubated for 5 days at 20°C and depletion of oxygen was found to be 5 ppm, B.O.D. of the sewage is
If 2% solution of a sewage sample is incubated for 5 days at 20°C and depletion of oxygen was found to be 5 ppm, B.O.D. of the sewage is
The ratio of maximum sewage flow to average sewage flow for trunk mains having diameters more than 1.25 m, is
The ratio of maximum sewage flow to average sewage flow for trunk mains having diameters more than 1.25 m, is
In primary sedimentation, the 0.2 mm inorganic solids get separated if specific gravity is
In primary sedimentation, the 0.2 mm inorganic solids get separated if specific gravity is
Nitrogen cycle of sewage, is
Nitrogen cycle of sewage, is
The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known
The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known
The use of coarse screens for the disposal of sewage, may be dispensed with by
The use of coarse screens for the disposal of sewage, may be dispensed with by
