environment water treatment Flashcards
Pick up the correct statement from the following :
[A]. Excess quantities of iron and manganese in water, cause discolouration of clothes
[B]. Lead and barium salts have toxic effect
[C]. Arsenic and selenium are poisonous to human health
[D]. Higher copper content affects the lungs
[E]. All the above. @
Pick up the correct statement from the following :
[A]. Excess quantities of iron and manganese in water, cause discolouration of clothes
[B]. Lead and barium salts have toxic effect
[C]. Arsenic and selenium are poisonous to human health
[D]. Higher copper content affects the lungs
[E]. All the above. @
Pick up the incorrect statement from the following regarding fire hydrants
[A]. Fire hydrants are fitted in water mains at 100 m to 150 m apart at fire
[B]. The minimum water pressure hydrants, is kept 1.5 kg/cm2
[C]. The water at pressure 1 to 1.5 kg/cm2 is made available for 4 to 5 hours for constant use
[D]. None of these. @
Pick up the incorrect statement from the following regarding fire hydrants
[A]. Fire hydrants are fitted in water mains at 100 m to 150 m apart at fire
[B]. The minimum water pressure hydrants, is kept 1.5 kg/cm2
[C]. The water at pressure 1 to 1.5 kg/cm2 is made available for 4 to 5 hours for constant use
[D]. None of these. @
Most commonly used pump for lifting water in water supply mains, is
[A]. axialflow pump @ [B]. reciprocating pump [C]. rotary type pump [D]. centrifugal pumps [E]. none of these
Most commonly used pump for lifting water in water supply mains, is
[A]. axialflow pump @ [B]. reciprocating pump [C]. rotary type pump [D]. centrifugal pumps [E]. none of these
Most satisfactory formula for an estimate of fire demand Q for a city of population P in thousands for Indian conditions, is
[A].
[B]. Q = 1640 P^0.5 (1 - 0.01 P^.5)
[C]. Q = 3180 P^0.5 @
[D]. none of these.
[C]. Q = 3180 P^0.5 @
kuchling formula
A high velocity of wash water is required for
[A]. rapid gravity filter with strainers [B]. rapid gravity filter without strainers @ [C]. slow sand filter with strainers [D]. slow sand filter without strainers [E]. none of these.
A high velocity of wash water is required for
[A]. rapid gravity filter with strainers [B]. rapid gravity filter without strainers @ [C]. slow sand filter with strainers [D]. slow sand filter without strainers [E]. none of these.
The maximum depth of sedimentation tanks is limited to
[A]. 2 m [B]. 3 m [C]. 4 m [D]. 5 m [E]. 6 m. @
Detention period: for plain sedimentation: 3 to 4 h, and for coagulated sedimentation: 2 to 2.5 h.
Velocity of flow: Not greater than 30 cm/min (horizontal flow).
Tank dimensions: L:B = 3 to 5:1. Generally L= 30 m (common) maximum 100 m. Breadth= 6 m to 10 m.
Circular: Diameter not greater than 60 m. generally 20 to 40 m.
Depth : 2.5 to 5.0 m (3 m).
Surface Overflow Rate: For plain sedimentation 12000 to 18000 L/d/m2 tank area; for thoroughly flocculated water 24000 to 30000 L/d/m2 tank area.
Slopes: Rectangular 1% towards an inlet and circular 8%.
The least thickness of class B cast iron (spun) pipe, is
[A]. 7.2 mm
[B]. 7.9 mm
[C]. 8.6 mm @
[D]. 10 mm.
8.6 is right answer and 7.9 is used for class A cast iron pipe.
The expected discharge to be obtained from an open well sunk in coarse sand is 0.0059 cumec. If the working depression head of the well is 3 m, the minimum diameter of the well, is
[A]. 2 m [B]. 2.25 m [C]. 2.50 m [D]. 2.75 m [E]. 3.00 m. @
Q = (k/A) * A * H
For coarse sand, k/A = 1,
For fine sand, k/A = 0.5,
For clay, k/A = 0.25.
Q = 0.0059 m^3/sec, Q = 0.0059 * 60 * 60 m^3/hour, A = (pi/4) * d^2.
If four fires break out in a city of population 40 lakhs and if each hydrant has three streams and duration of each fire is four hours, the total quantity of water required, is
[A]. 1880 kilo litres
[B]. 2880 kilo litres @
[C]. 3880 kilo litres
[D]. 4880 kilo litres.
Total quantity of water required = No of fires x Discharge x Time of each fire.
= 4 x (3 x 1000) x (4 x 60) = 2880000 liters = 2880 kilo liters. (where, 1000 liters/minute is discharge of each stream).
In slow sland filters, the turbidity of raw water can be removed only up to
[A]. 60 mg/litre @
[B]. 75 mg/litre
[C]. 100 gm/litre
[D]. 150 mg/litre.
Slow sand filter are not used for water turbidity greater than 50 NTU.
The best quality of filter material is obtained from quartzite if it does not loose weight when placed in hydro-chloric acid for 24 hours, more than
[A]. 5% @ [B]. 8% [C]. 10% [D]. 12% [E]. 15%.
5%
An area is declared drought affected if its mean rainfall is less than
[A]. 50% [B]. 60% [C]. 75% [D]. 80% [E]. 85%. @
The Indian Meteorological Department (IMD) has defined drought as a situation occurring in any area when the mean annual rainfall is less than 75% of the normal rainfall.
One degree of hardness of water means a content of salts of
[A]. 10.25 mg/litre [B]. 12.25 mg/litre [C]. 14.25 mg/litre @ [D]. 16.25 mg/litre. [E]. 20 mg/litre.
Hardness is represented in British scale, 1 degree hardness = 14.25 mg/l.
For french scale = 10 mg/l.
For amerucan scale = 17.15 mg/l.
Percussion drilling is unsuitable in
[A]. unconsolidated sand
[B]. unconsolidated gravel
[C]. quick sand
[D]. consolidated rocks. @
Percussion drilling is suitable for unconsolidated and consolidated formations:; sand, silt, stiff clay, sandstone, laterite and gravel layers depth up to 25m Unsuitable for rocks.
Normal values of overflow rate for plain sedimentation tank, is
[A]. 250 to 500 litres/hr/m2
[B]. 500 to 750 litres/hr/m2 @
[C]. 750 to 1000 litres/hr/m2
[D]. 1000 to 1250 litres/hr/m2.
Surface overflow rates:
Plain sedimentation :
V = 12 to 18 m3/day/m2.
V = 500 to 750 Liters/hr/m2.
Coagulation sediment:
V = 24 to 30 m3/day/m2. V = 1000 to 1250 Liters/hr/m2.
The period of cleaning of a slow sand filter, is usually
[A]. 5 to 10 days [B]. two weeks to three weeks [C]. one month to three months @ [D]. three months to six months [E]. one year.
The period of cleaning of a slow sand filter, is usually
[A]. 5 to 10 days [B]. two weeks to three weeks [C]. one month to three months @ [D]. three months to six months [E]. one year.
E. Coli bacterias die in water having pH greater than
[A]. 5.5 [B]. 6.5 [C]. 7.5 [D]. 8.5 [E]. 9.5 @
9.5 @
The valves provided at low points of pipes to drain off water quickly under gravity, are called
[A]. blow off valves
[B]. drain valves
[C]. sewer valves
[D]. all the above. @
Blow off valve. Drain valve. Sewer valve. Shut off valve. Flow off valve. Washout valve. Scour valve.
All are same.
The maximum pressure to which cast iron pipes may be subjected to, is
[A]. 3 kg/cm2
[B]. 5 kg/cm2
[C]. 7 kg/cm2 @
[D]. 10 kg/cm2.
It’s 0.77N/mm2 and 7kg/cm2.
The most commonly used chemical for dechlorination of water, is
[A]. sodium thiosulphate [B]. sodium bisulphate [C]. sodium sulphite @ [D]. sulphur-dioxide [E]. all the above.
C or A
For plain chlorination of water, the quantity of chlorine used, is
[A]. 0.1 mg/litre [B]. 0.2 mg/litre [C]. 0.3 mg/litre [D]. 0.4 mg/litre [E]. 0.5 mg/litre. @
Plain chlorination - 0.5mg/Lt.
Press chlorination - 0.1-0.5.
Post chlorination - 0.1-0.2.
The maximum permitted loss of head in a rapid sand filter, is
[A]. 1 m [B]. 2 m [C]. 3 m @ [D]. 4 m [E]. 5 m.
Slow sand filter:
Loss of head: 0.1 m ( initial limit).
: 0.8 to 1.2 m ( final limit).
Rapid sand filter :
Loss of head: 0.3 m ( initial limit).
: 2.5 to 3.0 m (final limit).
To control the growth of algae in reservoirs, the compound which is used, is
[A]. bleaching powder [B]. copper sulphate @ [C]. lime solution [D]. alum solution [E]. all the above.
To control the growth of algae in reservoirs, the compound which is used, is
[A]. bleaching powder [B]. copper sulphate @ [C]. lime solution [D]. alum solution [E]. all the above.
Pick up the wrong nominal internal diameter of cast iron (spun) pipes in mm from the following :
[A]. 300 [B]. 400 [C]. 500 [D]. 550 @ [E]. 600
Pick up the wrong nominal internal diameter of cast iron (spun) pipes in mm from the following :
[A]. 300 [B]. 400 [C]. 500 [D]. 550 @ [E]. 600
Sluice valves in main water supplies
[A]. are used to regulate the flow of water in pipes
[B]. are spaced about 5 km apart
[C]. are usually placed at the summits
[D]. all the above. @
Sluice valves in main water supplies
[A]. are used to regulate the flow of water in pipes
[B]. are spaced about 5 km apart
[C]. are usually placed at the summits
[D]. all the above. @
- Dead storage of a reservoir of Q capacity generally provided for silt deposition during its life time, is generally kept
[A]. 1/8th Q [B]. 1/6th Q [C]. 1/5th Q [D]. 1/4th Q @ [E]. 1/3rd Q.
Dead storage kept 20 to 25% of resevoir.
The formula Q = P - K[1.8T + 32] in which Q is runoff, P is annual rain fall in cm, T is mean annual temperature in centigrades and K is a constant, is known
[A]. Justin’s formula
[B]. Khosla’s formula @
[C]. English formula
[D]. Vermule’s formula.
The formula Q = P - K[1.8T + 32] in which Q is runoff, P is annual rain fall in cm, T is mean annual temperature in centigrades and K is a constant, is known
[A]. Justin’s formula
[B]. Khosla’s formula @
[C]. English formula
[D]. Vermule’s formula.
The maximum pressure which the pipe can withstand without any leakage during hydrostatic pressure test, is called
[A]. Working pressure
[B]. Design pressure
[C]. Test pressure @
[D]. Hydrostatic pressure.
The correct answer is D.
It is given in IS-458 in the section of;
3 - terminology - 3.3 hydrostatic test pressure.
Pick up the incorrect statement from the following :
[A]. Porosity of clay sand soil is 45% [B]. Porosity of pure sand is 35% [C]. Porosity of sand stone is up to 15% [D]. Least porosity is that of granite and quartz [E]. None of these. @
Pick up the incorrect statement from the following :
[A]. Porosity of clay sand soil is 45% [B]. Porosity of pure sand is 35% [C]. Porosity of sand stone is up to 15% [D]. Least porosity is that of granite and quartz [E]. None of these. @
Shrouding’ is essentially provided in
[A]. strainer type wells
[B]. cavity type wells
[C]. slotted type well @
[D]. all the above.
Shrouding’ is essentially provided in
[A]. strainer type wells
[B]. cavity type wells
[C]. slotted type well @
[D]. all the above.
Demand for public uses in a city, does not include water required for
[A]. watering of public parks
[B]. watering of public gardens
[C]. sprickling on roads
[D]. drinking purposes. @
Drinking purposes water demands come under domestic water demand.
The chloride content of treated water for public supplies should not exceed
[A]. 100 ppm [B]. 150 ppm [C]. 200 ppm [D]. 250 ppm @ [E]. 300 ppm.
250mg/l is the correct answer. According to IS 10500.
The U.C. (uniformity coefficient) D60 /D10 for the best filter media sand should be
[A]. 2 @ [B]. 3 [C]. 4 [D]. 5 [E]. none of these.
For RGF- 1.2 to 1.8.
For SSF- 1.8 to 2.5.
Manholes are less common in
[A]. cast iron pipes @
[B]. steel pipes
[C]. hume steel pipes
[D]. R.C.C. pipes.
Manholes are less common in
[A]. cast iron pipes @
[B]. steel pipes
[C]. hume steel pipes
[D]. R.C.C. pipes.
Asbestos pipes are joined by means of
[A]. flanged joint [B]. flexible joint [C]. dresser coupling joint [D]. simplex joint @ [E]. socket and spigot joint.
Asbestos pipes are joined by means of
[A]. flanged joint [B]. flexible joint [C]. dresser coupling joint [D]. simplex joint @ [E]. socket and spigot joint.
Abyssinian tube well is a special type of
[A]. slotted type wells
[B]. cavity type wells
[C]. strainer type well @
[D]. none of these.
Abyssinian tube well is a special type of
[A]. slotted type wells
[B]. cavity type wells
[C]. strainer type well @
[D]. none of these.
The efficiency of a pumping set, is generally assumed
[A]. 50% [B]. 55% [C]. 60% [D]. 65% @ [E]. 70%.
67%
The most important and widely used tube well in India, is
[A]. strainer well @
[B]. cavity well
[C]. slotted well
[D]. perforated pipe well.
The most important and widely used tube well in India, is
[A]. strainer well @
[B]. cavity well
[C]. slotted well
[D]. perforated pipe well.
Shales are
[A]. porous [B]. permeable [C]. porous and permeable [D]. porous but not permeable @ [E]. neither porous nor permeable.
Shales are
[A]. porous [B]. permeable [C]. porous and permeable [D]. porous but not permeable @ [E]. neither porous nor permeable.
Water is distributed to consumers by gravitational system, in
[A]. Dehradun [B]. Bombay [C]. Delhi [D]. Calcutta [E]. Both (a) and (b). @
Water is distributed to consumers by gravitational system, in
[A]. Dehradun [B]. Bombay [C]. Delhi [D]. Calcutta [E]. Both (a) and (b). @
The maximum permissible colour for domestic supplies based on cobalt scale, is
[A]. 5 ppm [B]. 10 ppm [C]. 15 ppm [D]. 20 ppm @ [E]. 25 ppm.
5-25 ppm is for TCU(true colour unit) and 10-20 is for cobalt scale.
The joint used for joining the plain ends of cast iron pipes, is
[A]. flanged joint [B]. socket and spigot joint . [C]. dresser coupling joint @ [D]. flexible joint [E]. expansion joint
The joint used for joining the plain ends of cast iron pipes, is
[A]. flanged joint [B]. socket and spigot joint . [C]. dresser coupling joint @ [D]. flexible joint [E]. expansion joint
The gaseous form of chlorine gets converted into liquid form when subjected to a pressure of
[A]. 5 kg/cm2 [B]. 6 kg/cm2 [C]. 7 kg/cm2 @ [D]. 8 kg/cm2 [E]. 10 kg/cm2.
The gaseous form of chlorine gets converted into liquid form when subjected to a pressure of
[A]. 5 kg/cm2 [B]. 6 kg/cm2 [C]. 7 kg/cm2 @ [D]. 8 kg/cm2 [E]. 10 kg/cm2.
P.V.C. pipes can withstand pressure bead of water upto
[A]. 25 m [B]. 50 m [C]. 75 m [D]. 100 m @ [E]. 125 m.
P.V.C. pipes can withstand pressure bead of water upto
[A]. 25 m [B]. 50 m [C]. 75 m [D]. 100 m @ [E]. 125 m.
Air inlet valve in water mains, is generally provided at
[A]. summit of the pipe [B]. upstream of sluice valve [C]. down stream of sluice valve [D]. valley of the pipe [E]. both (a) and (c) of above. @
Air inlet valve - down stream of sluice valve.
Pressure relief Valve - Up stream of sluice valve.
The duration of contact of chlorine with water before it is served to the first consumer, should be at least
[A]. 10 to 15 minutes [B]. 15 to 20 minutes [C]. 20 to 30 minutes @ [D]. 30 to 40 minutes [E]. one hour.
Because 0.5mg per litre up to 20 to 30 minutes is enough for disinfection of bacteria.
For least effect on the water table, the tube wells must be dug one in every
[A]. 0.5 sq km [B]. 0.75 sq km [C]. 1.0 sq km [D]. 1.25 sq km [E]. 1.5 sq km. @
For least effect on the water table, the tube wells must be dug one in every
[A]. 0.5 sq km [B]. 0.75 sq km [C]. 1.0 sq km [D]. 1.25 sq km [E]. 1.5 sq km. @
In plain sedimentation tanks under normal conditions, impurities are removed upto
[A]. 60%
[B]. 70% @
[C]. 80%
[D]. 90%.
In plain sedimentation tanks under normal conditions, impurities are removed upto
[A]. 60%
[B]. 70% @
[C]. 80%
[D]. 90%.
The valve fitted closely in a recess against an opening in a pipe, is generally
[A]. wedge shaped circular disc @
[B]. spherical disc
[C]. parallelopiped disc
[D]. conical shaped circular disc.
The valve fitted closely in a recess against an opening in a pipe, is generally
[A]. wedge shaped circular disc @
[B]. spherical disc
[C]. parallelopiped disc
[D]. conical shaped circular disc.
The maximum non-verticality of the bore of a well 200 m deep, may be permitted up to
[A]. 25 cm [B]. 50 cm [C]. 75 cm [D]. 100 cm @ [E]. 150 cm.
The maximum non-verticality of the bore of a well 200 m deep, may be permitted up to
[A]. 25 cm [B]. 50 cm [C]. 75 cm [D]. 100 cm @ [E]. 150 cm.
By adding 1 ml of orthotolidine solution to 100 ml chlorinated water taken after contact period, the residual chlorine makes the colour of solution
[A]. yellowish @ [B]. greenish [C]. bluish [D]. reddish [E]. violet.
By adding 1 ml of orthotolidine solution to 100 ml chlorinated water taken after contact period, the residual chlorine makes the colour of solution
[A]. yellowish @ [B]. greenish [C]. bluish [D]. reddish [E]. violet.
Pick up the incorrect statement from the following :
[A]. Iron salts produce heavy flocs and hence remove more suspended matter
[B]. Iron salts remove hydrogen sulphides
[C]. Iron salts can be used over a limited range of pH values @
[D]. Iron salts impart corrosiveness to water.
Pick up the incorrect statement from the following :
[A]. Iron salts produce heavy flocs and hence remove more suspended matter
[B]. Iron salts remove hydrogen sulphides
[C]. Iron salts can be used over a limited range of pH values @
[D]. Iron salts impart corrosiveness to water.
The percentage of chlorine in fresh bleaching powder is roughly
[A]. 50 to 60
[B]. 30 to 35 @
[C]. 40 to 50
[D]. 20 to 25
Because CaOcl2 Ocl- is 16+35.5 and CaOcl2 is 40+16+71 = 127.
So, 51.5/127 = 405*100 = 40%.
The intake opening is generally covered by a screen to prevent entry of debris etc. and its level is kept
[A]. at the level of water of the source
[B]. at the bottom of water of the source
[C]. at about 2.5 m above the bottom @
[D]. none of these.
The intake opening is generally covered by a screen to prevent entry of debris etc. and its level is kept
[A]. at the level of water of the source
[B]. at the bottom of water of the source
[C]. at about 2.5 m above the bottom @
[D]. none of these.
In rapid sand filters the ratio of length and diameter of the lateral, should not be greater than
[A]. 10
[B]. 15
[C]. 20 @
[D]. 25
60 in book
Plain chlorination is used for water
[A]. with turbidities less than 20 mg/litre [B]. obtained from clear lakes [C]. consumed during emergencies [D]. supplies to armies during war [E]. all the above. @
Plain chlorination is used for water
[A]. with turbidities less than 20 mg/litre [B]. obtained from clear lakes [C]. consumed during emergencies [D]. supplies to armies during war [E]. all the above. @
Rapid gravity filters can remove bacterial impurities up to a maximum of
[A]. 50% [B]. 60% [C]. 70% [D]. 80% @ [E]. 90%.
The rate of filtration - 3000-6000L/m^2/hour.
Bacteria removal - about 80 to 90%.
Turbidity removal 35-40 mg/l.
slow sand filter
Rate of filtration - to 200L/m2/hour.
Bacteria Removal - 98%to 99%.
Turbidity removal 50ppm.
Colour removal- 30ppm.
Low turbidity of water is detected by
[A]. Turbidity tube [B]. Jackson turbidity meter [C]. Baylis turbidimeter @ [D]. Hellipe turbidimeter [E]. None of these.
Jackson turbidity meter range is 0-1000ppm.
Hellige turbidity meter range is 0-50 ppm
Baylis turbidity meter range is 0-2 ppm.
Nephlometer range = 0-1 ppm
For complete stabilisation of organic matter in polluted water, it takes
[A]. 5 days [B]. 10 days [C]. 20 days [D]. 30 days @ [E]. 40 days.
For complete stabilisation of organic matter in polluted water, it takes
[A]. 5 days [B]. 10 days [C]. 20 days [D]. 30 days @ [E]. 40 days.
For 3.25 x 10-2 cumecs discharging from a well, a pump is installed to lift water against a total head of 30 m. The minimum required horse power, is
[A]. 10 H.P. [B]. 15 H.P. [C]. 18 H.P. [D]. 20 H.P. @ [E]. 25 H.P.
P=WQH/75 * efficiency of the pump.
Assume maximum efficiency of the pump=65%.
Then,p=10 * 3.25 * 10^-2 * 30/75 * 0.65.
P=0.2 * 100.
P=20HP.
