WBPSC AE 1998 (Public Health Engineering) question paper with answers

Q1.Population forecast for determining future water demand is best judged by

1. Arithmetic increase
2. Geometrical increase
3. Graphically by comparison with similar town
4. Ultimate density of population

Q2.Average water demand of a small town in India is estimated on the basis of

1. Domestic use
2. Domestic use + Public use + Wastage
3. Domestic use + Public use
4. Domestic use + Public use + wastage + Firedemand

Q3.Ground water normally has the following characteristics

1. Low mineralised content
2. Soft
3. pH below 7
4. High dissolved oxygen

Q4.An impounding reservoir is used in water supply system to

1. evenly distribute water amongst the consumers
2. maintain a uniform rate of supply to the township
3. maintain an equitable pressure in the distribution system
4. obtain a uniform quality of water

Q5.The mode of sinking small diameter deep tubewells in alluvial soil is

1. Rotary drill with water jet
2. Driving it into the soil to reach the aquifer
3. Boring with suitable anger
4. Reverse rotary method

Q6.Valve to be used at the summit of a transmission line is

1. Reflux valve
2. Air Valve
3. Pressure relief valve
4. Scour valve

Q7.An infiltration gallery is used to obtain water from

1. a well sank in a river bed
2. a trench dug in riger bed
3. perforated pipe laid in a trench in a river bed
4. impounded reservoir

Q8.Excessive concentration of sodium in water

1. is toxic to plants
2. causes colour problem
3. Prevents corrosion of metal surface
4. causes taste and odour problem

Q9.Suggested residual chlorine in drinking water supplies, after 30 minites of contact, is normally

1. 1 to 2 mg/l
2. 0.6 to 0.9 mg/l
3. 0.2 to 0.5 mg/l
4. 0.1 to 0.15 mg/l

Q10.Water demand for a town of given population is function of

1. standard of living
2. size of the town
3. distance of the water source
4. type of water source

Q11.Disinfection is the only reaquired treatment when the source of water is

1. lake
2. slow moving river
3. deep tubewell
4. impounded reservoir

Q12.Sluage digastion processes gas with maximum content of

1. methane
2. carbondi-oxide
3. nitrogen
4. hydrogen sulphide

Q13.Higher turbidity in water supplies is objectionable, because

1. consumers prefer a less turbid water even though it may be unsafe
2. it results in incrustrations in pipes and clogs appurtenances
3. it encourages after growth of bacteria in distribution system
4. due to prolonged use, it may cause cardiovasoular diseases in consumers

Q14.In many commuity water supply, then feacal coliform density should not be more than

1. 4 per 100 ml
2. 6 per ml
3. 25 per ml
4. 0 per 100 ml

Q15.Which one of the following diseases may be caused by contained drinking water?

1. malaria
2. Filaria
3. Typhoid
4. Tuberculosis

Q16.Recommended per capita water demand for domestic purpose in Indian cities may be taken as

1. 70 Lpcd
2. 135 Lpcd
3. 270 Lpcd
4. 40 Lpcd

Q17.Permanent hardness of water is due to the presence of

1. bicaronates of calcium and magnesium
2. toxic materials
3. metallic oxides
4. sulphate and clorides of calcium and magenesium

Q18.B.O.D. in water signifies presence of

1. Total organic load
2. Biodegradable organic load
3. Non-biodegradable organic load
4. Total load

Q19.Growth of algae in a water body tends to increase with the latter's

1. turbidity
2. alkalinity
3. hardness
4. acidity

Q20.The disease "Methaemoglobinemia" is caused when drinking water supplies contain high concentration of

1. Fluoride
2. Nitrate
3. Nitrite
4. Chloride

Q21.Water used in boilers should be

1. relatively hard
2. relatively soft
3. high in sodium content
4. free from pathogens

Q22.Velocity of ground water may be measured

1. with the help of dyes or salts
2. with the help of pumps
3. with the help of sounding rods
4. with the help of piot tub

Q23.When water is pumped out from a well

1. a cone of dipression is formed all around
2. the aquifer is immediately fully recharged
3. specific yield increases
4. the water table is not disturbed

Q24.Shrouding of tubewells is generally done

1. with pea gravels
2. with fine sand
3. with clay
4. with cement slurry

Q25.Temporary hardness in water is due to the presence of

1. Carbonates
2. Sulfates
3. Chlorides
4. Dissolved carbon di-oxide

Q26.Crown corrosion in sewer is caused due to the presence of

1. Nitrate
2. Bromide
3. Sulfate
4. Chloride

Q27.The peak factor for estimating maximum hourly demand relative to maximum daily demand is

1. 1.8
2. 1.5
3. 2.7
4. 2.0

Q28.Effective size to be used in rapid sand gravity filter is

1. 0.15-0.30 mm
2. 0.45-0.70 mm
3. 0.75-0.90 mm
4. 0.95-1.100 mm

Q29.Standard rate of filtration in slow said filters is

1. 25-50 ltr/hr
2. 50-90 ltr/hr
3. 100-150 ltr/hr
4. 160-200 ltr/hr

Q30.Overflow rate for secondary setting tank for activated sludge treatment in m³/d/m

1. 10-15
2. 15-35
3. 35-45
4. 45-60

Q31.In conventional activated sludge treatment plant the return sludge is added at

1. entrance of the aeration tank
2. 1/3 away from the inlet end of the areation tnak
3. 1/2 away from the intel end of the areation tank
4. at the outlet end of the areation tank

Q32.A.B.O.D. removal efficiency of 95% can be expected from

1. Septic tank
2. Imhoff tank
3. standard filter
4. Activated sludge plant

Q33.In a conventinal sewage treatment plant employing trickling fillters the grit chamber is placed

1. ahead of primary setting tank
2. ahead of the trickling filter
3. ahead the secondary setting tank
4. following the secondary setting tank

Q34.The pH value to be maintained in the digestion zone of a sludge digester is

1. 5.5-6.5
2. 7-8
3. 8.5-9.5
4. above 10.0

Q35.Self cleansing velocity recommended for sanity sewers is

1. 0.5 mps
2. 0.6 mps
3. 0.8 mps
4. 1.0 mps

Q36.Sewers should not be designed to run full

1. to prevent escape of sewage
2. to prevent scouring of sewer
3. to facilitate ventilation of sewers
4. to facilitate cleaning of sewers

Q37.Considering the dydroulic properties, the best shape of swwere should be

1. square
2. circular
3. oval
4. egg-shaped

Q38.During sewer cleaning the workers are exposed to hazards primarily due to

1. presence of methane
2. absence of oxygen
3. hazardous chemicals
4. slippery floors of the manholes

Q39.Flushing manholes are usually located at the

1. ahead of the sewer
2. junction of branch sewer and trunk sewer
3. at an interval of 1000 metres on straight alignments
4. in the house drainage system

Q40.The equation used commonly for the design of distribution system for water supply is designed by

1. Darcy
2. Manning
3. Kutter
4. Hazen & Williams

Q41.Removel of excessive iron from public water supply is usually done by

1. aeration
2. chemical precipition
3. coagulation
4. ion exchange

Q42.The process of biological waste treatment in stabilisation ponds is governend by

1. bacterial degradation
2. algal-bacterial symbiosis
3. photo synthesis
4. settlement of suspended solids

Q43.Sludge digestion produces gas with maximum content of

1. methane
2. cabon di-oxide
3. Nitrogen
4. Hydrogen sulpide

Q44.Sludge drying beds are used to separate water from

1. raw sludge
2. primary raw sludge
3. activated excess sludge
4. digested sludge

Q45.Strength of sewage is normally given by the concentration of

1. pathogenic organisms
2. phosphorous
3. organic matter
4. sulphates

Q46.Corrosion of concreate sewer occurs due to

1. high volocity of flow of sewage
2. an aerobic decomposition of sewage solids
3. aerobic decomposition of sewave solids
4. high pH value of the sewage

Q47.Parshall flume is primarilly provided in the downstream side of the grit chamber of act as dvice

1. oxygenation
2. velocity control
3. Floating material removal
4. putrescible material removal

Q48.The shape of a trickling filter is circular because of

1. convenience of construction
2. its good appearance
3. convenience of uniform distribution of waste water
4. convenience of placing the filltering media

Q49.For typical untreated domestic waste water, B.O.D./C.O.D. ratio varies from

1. 0.20 to 0.40
2. 0.40 to 0.80
3. 0.80 to 0.90
4. 1.0 to 1.2

Q50.The type of valve which is prodided to control the flow of water in the distribution system at street corners and where pipelines intereect is

1. Cheek valve
2. Sluice valve
3. Safety valve
4. scour valve

Q51.The chemical names for common alum is

1. aluminum sulphate
2. aluminium hydroxide
3. aluminium chloride
4. copper sulphate

Q52.In double fitration, the name of the first filter is

1. roughing filter
2. pressure filter
3. rapid sand filter
4. gravity filter

Q53.Lime-soda process is adopted to remove from water

1. odour and taste
2. temporary hardness
3. lead
4. permanent hardness

Q54.Biological treatment of sewage takes place in

1. grit chamber
2. Primary setting tank
3. trickling filter
4. secondary settling tank

Q55.The valve used for regulating the flow of water in an out flow pipe of verhead reservoir is called

1. reflux valve
2. scour valve
3. gate valve
4. air-relief valve

Q56.Pipe material generally used in India for conveying water is

1. lead
2. cast iron
3. copper
4. wrought iron

Q57.The valve in a pipeline which allows flow in one direction only is called

1. sluice valve
2. airvalve
3. reflux valve
4. scour valve

Q58.Ferrule is one of the important appurtenances installed in

1. combined sewerage system
2. water distribution system
3. house drainage system
4. storm sewerage system

Q59.Recirulation in activated sludge process is adopted to

1. dilute the incoming sewage
2. dampen the effect of flow variation
3. supply seed materials to areation tank
4. operate the plant continuously

Q60.Hazen-williams 'c' for a 20-year old C.I. Pipe could be around

1. 130
2. 110 to 120
3. 99 to 100
4. 75 to 90

Q61.The removal of taste and odour from water is accomplished best by

1. filtration
2. coagulation
3. chlorine-ammonia
4. adsorption

Q62.The principal objective of the coagulation flocculation unit of a water treatment plant is removal of

1. pathogens
2. soluble impurities
3. colloidal impurities
4. dissolved gases

Q63.In a conventional water treatment plant vigouous mixing is done in a

1. clerifier
2. flocculation chamber
3. chamber where coagulant is added
4. rapid sand filter

Q64.Length of run of a rapid sand filter may range from

1. 24 to 48 hours
2. 7 to 15 days
3. 15 to 60 minutes
4. 1 to 3 months

Q65.One of the disadvantages associated with the use of ozone as a disinfectant is that the necessary residual ozone gae.

1. can serverly corrode pipes
2. cannot be maintained
3. can impart strong taste to water
4. can induce cancer

Q66.Hydraulic radius of a circular conduit of diameter 'D' while flowing full, is given by

1. D/4
2. D/2
3. (3/4)√D
4. √D

Q67.The working conditions in imhoff tanks.

1. aerobic only
2. aneorabic only
3. aerobic in lower compartment and aneorobic in upper compartment
4. anerobic in lower compartment and aerobic in uppen compartment

Q68.Sloughting phenomemon is observed in

1. oxidtion
2. septic tank
3. aeration tank
4. trickling filter

Q69.Odour of hydrogen sulphide is emitted from dometic waste water when

1. pH valve is high
2. bacteria present in aerobic
3. dissolved oxygen is absent
4. dissolved oxygen is high

Q70.With what substance would water be treated to remove algae?

1. copper sulphage
2. alum
3. greensand
4. polyphosphate

Q71.Most hygienic method of disposal of solid waste is

1. dumpin on low lying lands
2. composting
3. incineration
4. dumping in tanks and ponds

Q72.The pollution of the ambient air due to stack emissions is better controlled by

1. lowering the stack height
2. raising the stack height
3. reducing the cross-sectional area of the stack
4. increasing the cross-sectional area of the stack

Q73.The hazard of auto emission is primarily due to

1. SPM
2. NOx
3. Smoke
4. CH4

Q74.Cyclones are used to arrest

1. SPM
2. SO2
3. Pb
4. NOx

Q75.Common parameters used to determine the extent of pollution in ambient air

1. SO2, CO, Ph
2. SPM, SO2, NOx
3. H2S, CO, CO2
4. PH, SPM, CO2

Q76.Type of pumps most generally used in sewage puming area:

1. axial flow screw pumps
2. air ejectors
3. centrifugal pumps
4. submersible pumps

Q77.Increasing concentration of atmospheric carbon di-oxide may result in

1. increase in humidity
2. atmospheric turbidity
3. greenhouse effect
4. decrease in atmospheric temperature

Q78.The gaseous pollutant in air which combines with haemoglobin in blood is

1. ozone
2. sulphur di-oxide
3. carbon monoxide
4. carbon di-oxide

Q79.The intensity of air pollution is found to be the highest during

1. Summer
2. monsoon
3. winter
4. spring

Q80.Pyrolysis is a process of

1. oxidation at high temperature
2. combustion at ambient temperature
3. purification with oxygen
4. heating in an oxygen-free atmosphere

Q81.Which of the following is expected to be the major constituent of municipal solid waste in developing countries?

1. Dust and cinder
2. Paper
3. Glass
4. Vegetable and putrescible matter

Q82.Which of the following air pollutants causes irrigation of the yee?

1. Photo-chemical oxidants
2. ozone
3. carbon monoxide
4. sulphur oxides

Q83.Ozone layer in the upper atmpsphere is getting destroyed owing its reaction with pollutants like

1. Hyrogen peroxide
2. Carboon monoxide
3. Volatile organic acids
4. chlorofluoro carbons

Q84.One of the air pollutants responsible for damage to limestone surfaces is the presence of

1. SO2
2. N2O
3. CO
4. Hydrocarbons (unburned)

Q85.Electrostatic precoitators are used to control air pollution due to

1. SO2
2. Suspended particulates
3. NOx
4. peroxy-acetyle nitrate (PAN)

Q86.On mass basis, the larges fraction of the solid wastes from a typical Indian city is made up of substances which are essentially

1. Salvagable
2. combustibles
3. non-combustible inorganics
4. compostibles

Q87.A sample of water collected from a lake during day time was found to be highly supersaturated with dissolved oxygen. The cause of this supersaturation could be

1. intense aerobic bacterial activity
2. release of oxygen from bottom depsosits
3. absence of organic pollution
4. production of oxygen due to algal photosynthesis

Q88.Dissolved oxygen content of a water sample can be messured in laboratory by

1. Winkler method
2. Arogentimetric method
3. orthotolidin-airsemite method
4. Jar test method

Q89.Control equipment for SO2 gas is usually

1. a cyclone separator
2. a packed bed of pulverised limestone
3. a fabric filter
4. an electrostatic precipitator

Q90."Whirling Psychrometer" is used to measure

1. wind speed
2. solar radiation
3. relative humidity
4. atmospheric stahility

Q91.Europlication is water bodied are caused due to presence of high levels of

1. nitrogen and phosphorous
2. Oxygen demanding matrials
3. toxic organic substances
4. heated water from industrial units

Q92.Jackson candle turbidimeter measures turbidity of a sample of water on the basic of

1. Scattering of light
2. absorption of light
3. polarisation of light
4. concentration of colloids

Q93.A good water-bearing strata or auifer is composed of

1. coarse sand
2. Hard rock with fissures
3. Silt and clay
4. Very fine sand

Q94.Normal dosage of chlorine in public water supply scheme is

1. 1.5 to 2.5 mg/l
2. 0.5 to 1.0 mg/l
3. 0.05 to 0.2 mg/l
4. 0.2 to 0.5 mg/l

Q95.The slow sand filter is more efficient in removing bacteria because

1. effective size of sand grains in small
2. uniformity co-efficient of sand grains is small
3. water is pretreated
4. Size of filter bed is large

Q96.In a sewerage system flushing tank is located at

1. intersection of two sewers at different levels
2. at sumit end of sewer
3. sewere line with steep gradient
4. intersection of two sewers of different sizes

Q97.Provision of inverted siphons is made when

1. a sewer line crosses a river
2. two sewers meet
3. a sewer line is laid on steep slope
4. two roads meet

Q98.The efficiency of a clarifier, handling flocculant suspension depends on

1. overflow rate
2. depth of the clarifier
3. overflow rete and depth of the clarifier
4. weir oberflow rate only

Q99.A velocity control deoics has to be provided in a

1. slow and filter
2. aeration tank
3. grit chamber
4. flow equalization tank