Environmental Engineering Flashcards
Suspended solid present in the waste water generated in blast furnace gas cooling and cleaning plant is removed by
radial settling tank (thickener) using coagulant (lime & ferrous sulphate)
Persons working in cement plants and limestone quarries are more prone to disease like
silicosis
Particulates (< 1μm size) remaining suspended in air indefinitely and transported by wind currents are called
aerosols
Operating principle of cyclone separator is based on the action of __________ dust particles.
centrifugal force on
Exposure to small amount of __________ results in high blood pressure & heart disease in human beings.
cadmium
Maximum allowable concentration of CO2 in air for safe working is __________ ppm (parts per million).
5000
Tolerable limit of nitrogen oxides in air is __________ ppm.
5
Iron & manganese present as pollutant in water can not be removed by
chlorination
In water chemical treatment plant, use of chloramines ensures
disinfection
Which of the following is the common pollutant emitted from metallurgical smelters, thermal power plant and cement plants ?
SO2
During which of the following operating conditions of an automobile, carbon monoxide content in the exhaust gas is maximum ?
Idle running
H2S present in gaseous stream can be removed by adsorption on
bog iron
Inhalation of lead compounds present in automobile exhaust (using leaded petrol) causes
all (a), (b) & (c)
Replenishment of dissolved oxygen in water stream polluted with industrial waste occurs by
both (a) & (b).
Aerodynamic noise resulting from turbulent gas flow is the most prevalent source of valve noise in fluid allow control. It is caused due to
both (a) & (b)
Smoke is produced due to
all (a), (b) and (c).
fluorosis (a bone disease) is caused by the presence of high concentration of __________ in atmospheric air.
hydrogen fluoride
Threshold Limit Value (TLV) is the maximum allowable concentration (i.e. safe limit) of pollutants in air. Safe limit for SO2 in air is __________ ppm.
5
Main pollutants released from iron & steel industry is
CO, CO2 & SO2.
Scale formation in boiler is controlled by
reduction in hardness, silica & alumina in feed water.
Which is the best and the most effective method for the removal of organic contaminant present in the polluted water in very small quantity (say < 200 mg/litre)?
Activated carbon adsorption
Which is a secondary air pollutant ?
Photochemical smog
Which of the following is the most detrimental for water used in high pressure boiler ?
Silica
Turbidity of water is an indication of the presence of
suspended inorganic matter
Presence of excess flourine in water causes
fluorosis
rosis is a disease caused by the inhalation of __________ dust.
iron
Which of the following pollutants is not emitted during volcanic eruptions ?
hydrocarbons
The main pollutant in waste water discharged from a petroleum refinery is oil (both in free and emulsified form). Free oil is removed by
gravity separator having oil skimming devices.
Phenolic water generated in coke ovens & by-product plant attached to an integrated steel plant containing phenol in concentration of less than 100 mg/litre can be removed by
treating in biological oxygen pond
Which of the following dust collection equipments is the least efficient (for sub-micronic particles) ?
Dust catcher (gravity type)
Dust collection efficiency of a cyclone separator depends upon its
all (a), (b) & (c).
Bag filter design is predominantly dependent on gas temperature, as it affects the gas density & viscosity and the selection of filtering material. The pressure drop in a bag filter is
both (b) and (c).
The widest explosive limit is of __________ , thereby making it the most explosive gas.
acetylene
Aerobic biological oxidation ponds used for the purification of polluted water
all (a), (b) & (c).
Polluted water having low BOD are most economically treated in
oxidation ponds
Tri-sodium phosphate is used in boiler water treatment to reduce
caustic embrittlement
The commonest form of iron & manganese found in ground water as pollutant is in the form of their
bi-carbonates
80% less than 200 mesh size particles are called
powder
Coal washing waste water containing about 3% suspended solids (comprising of clay, slate, stone etc.) is treated for solid particles removal
in sedimentation tanks equipped with mechanical scrapper.
Inhalation of lead compounds present in the automobile exhausts (using leaded petrol) causes
all (a), (b) and (c).
TLV of ozone (O3) and phosgene (COCl2) in air is __________ ppm.
0.1
Most of the atmospheric air pollutants are present in large quantity in
troposphere
Pick out the wrong statement.
Cooling and freezing of water kills the bacteria present in it.
‘Pneumoconiosis’ is a disease caused by the inhalation of __________ dust.
coal
The ratio of oxygen available to the oxygen required for stabilization of sewage is called the
relative stability.
Pick out the wrong statement.
The radio waves used in the long distance radio communication are reflected back to earth by stratosphere.
Most efficient and suitable dust removal equipment for removal of flyash from flue gas in a thermal power plant is the
electrostatic precipitator
Which of the following is not a secondary air pollutant ?
Sulphur dioxide
The concentration of water vapour in troposphere, which depends upon the altitude & temperature varies in the range of zero to __________ percent.
4
The main industrial source of emission of hydrogen sulphide air pollutant is
coal based thermal power plants
Waste/polluted water discharged from electroplating, blast furnace and coal mining industries contain mainly __________ substances.
inorganic
Moist atmospheric air at high temperature (e.g., in summer) having high concentration of sulphur dioxide causes
all (a), (b) and (c)
Nitrogen oxides (NOx) is not produced in the __________ industry.
detergent
World’s worst radioactive pollution was caused by nuclear reactor disaster which occured in
Chernobyl (undivided U.S.S.R.)
Oil and grease present in an emulsified state in waste water discharged from industries can be removed by
settling out using chemical reagents.
The amount of chemical coagulant added for treatment of polluted water __________ with increase in temperature of the polluted water to be treated.
decreases.
Particles having diameter greater than 75 μm (micrometer = 10-6 mm) are called
grit
Which of the following is the most severe air pollutant ?
NOx
Presence of bacteria in potable (drinking) water causes
disease
What are the methods of treatment & disposal of radioactive wastes ?
All (a), (b) & (c).
Bacterial aerobic oxidation of polluted water in biological oxidation ponds is done to purify it. Presence of bacteria helps in
all (a), (b) and (c)
Main pollutant present in automobile exhaust is
CO
Maximum allowable noise exposure limits for a man working for 8 hours a day in a noisy chemical plant is about __________ decibels.
90
Industrial workers working in leather tanning & manufacturing units are prone to suffer from
skin diseases (e.g. dermatities).
Pick out the wrong statement.
The characteristic of a green house body is that it allows the long wavelength incoming solar radiation to come in but does not allow the short wavelength infra red radiation to escape out of the earth’s atmosphere.
Peroxyacyl nitrate (PAN), a pollutant is found in the
automobile exhaust.
Foaming and priming in boiler operation can be reduced by reduction in __________ in feed water.
all (a), (b) & (c)
Ambient noise level can be reduced by __________ decibels by planting trees (like coconut, neem etc.) near public utility buildings (like hospitals & schools).
5-10
Pick out the wrong statement.
Sulphur dioxide is the main pollutant emitted from the exhaust of petrol driven automobiles.
COD of raw municipal sewage may be in the range of about __________ mg/litre.
90-120
Maximum permissible turbidity in potable water is __________ ppm.
10
Presence of __________ hardness is responsible for the temporary hardness in water.
Calcium
A shallow pond in which the sewage is retained and biologically treated is called
oxidation
Which is the most practical and economical method for removal of suspended solid matter from polluted water ?
Sedimentation
Atmospheric pollution caused by the exhaust gas of supersonic transport air-crafts is mostly in the atmospheric region called
stratosphere
Iron & manganese present in the polluted water is removed by
oxidation followed by settling & filtration.
Water effluent generated in printing industry is decolorized by
electrolytic decomposition.
Thermal pollution of water increases its toxicity and oxidation of oxygen demanding waste besides favouring bacterial growth. A rise in water temperature by 10°C, doubles the toxic effects of __________ present in it.
potassium cyanide
__________ can not control the noise pollution.
Green House gases
Noise level during normal conversation among men is about __________ decibles.
45
Foul odour and bad taste of water is removed by treating with
activated carbon
Acute danger to human life (i.e. death) exists, if the concentration of CO2 in atmospheric air exceeds __________ percent (by volume).
20
Presence of volatile compounds like gasoline, oil, alcohol, ether etc. in municipal sewers may cause
explosion
Presence of soluble organics in polluted water causes
depletion of oxygen.
Which of the following pollutants, if present in atmosphere is detectable by its odour ?
SO^2
Exposure to chemicals having carcinogenic properties cause
cancer
In water treatment plant, zeolite process is used to remove the __________ of water.
hardness
Fresh sewage is __________ in nature.
alkaline
Workers working in __________ industry are most prone to white lung cancer.
textile
On prolonged exposure to high concentration of carbon monoxide (> 5000 ppm), man dies because
it forms carboxyhemoglobin by combining with hemoglobin of blood, thereby making it incapable of absorbing oxygen.
A standard test for determination of hardness in water is termed as __________ test.
EDTA
TLV of lead for public sewer/waste water is about __________ ppm.
1
Presence of nitrates in water in excess of 50 ppm causes
methemoglobinemia
In sewage treatment, the detention period allowed for oxidation ponds ranges from __________ weeks.
4 to 5
Coal mines drainage waste water (acidic in nature) results from the earth’s water percolating through the voids created in coal bed during mining. This polluted water which either drains out naturally to water courses or are removed before starting the mining is
neutralised by alkali treatment.
Fine grit present in sewage is removed in the __________ during sewage treatment.
detritus tank
The lowest layer of atmosphere is known as the
troposphere
Which of the following is not a weightless pollutant ?
SPM
Global warming may result in
all of the above
Which of the following is the most lethal water pollutant ?
Phenol and cynide
Presence of carbon monoxide in atmosphere produced by decomposition of chlorophyl and haemoglobin breakdown of some animals, beyond TLV (>50 ppm)
causes asphyxia.
The earth’s atmosphere is an envelope of gases present up to a height of about __________ kms.
200
Which of the following is an adsorbant used for the removal of SO2 from gas/air ?
Limestone powder or alkalized alumina
Higher concentration of nitrogen dioxide in atmospheric air causes
bronchitis
Ozone is
both (b) and (c)
The permissible color for domestic water supply is __________ ppm.
20
High noise levels produced during operation of fans and compressors can be reduced by using
mufflers (silencers).
The Killer gas which caused Bhopal gas tragedy in 1984 was
methyl iso-cynate (MIC)
Aerosols present in atmospheric air may be
combination of all (a), (b) & (c).
Ethanolamine is an absorbant used for the removal of __________ from air/gas.
both (b) & (c)
Which of the following causes death by asphyxiation, if its presence in atmospheric air exceeds maximum allowable concentration (i.e. > 50 ppm)
Carbon monoxide
__________ plant emits large amount of SO2 as an air pollutant.
Sulphuric acid
Noise pollution level in a chemical plant is expressed in
decibel
The most commonly used chemical coagulant in water treatment is
alum
The biological decomposition of organic substances in wastes controlled conditions is called
composting
Lung cancer & DNA breakage are the major ill effects of excessive ozone exposure to human beings. Ozone layer depletion in the atmosphere is mainly caused by the presence of
CFC (chloro fluoro carbon)
Smog is not formed due to the presence of __________ in the atmosphere.
CO2
Pick out the correct statement.
Global warming is detrimental for increase in food productivity and may cause flood and cyclone.
Which of the following is not a source of ozone emission in the atmosphere ?
Refrigerators.
Oceans act as sinks for atmospheric gases including carbon dioxide whose concentration in the atmosphere is increased by the
green house effect
Pick out the correct statement.
all (a), (b) and (c).
The upper layer of atmosphere is called the
stratosphere
Which of the following is the most widely used disinfectant in water treatment ?
Chlorine
Phenolic water generated in coke ovens & by-product plant of a steel plant are disposed off by
quenching of hot coke.
Pick out the wrong statement
Carbon monoxide present in the two stroke petrol engine exhaust is much less as compared to that emitted from a four stroke engine.
The progressive warming up of the earth’s surface is mainly due to the
blanketing effect of CO2 in the atmosphere
The effect of increase in carbon dioxide level of the atmosphere and its profound effect on our climate is called the
both (b) and (c)
Arsenic pollutant is not generated in____industries
beverages
The resistance of water to the passage of light through it is a measure of the
turbidity
Color test of water is done with an instrument called
tintometer
Which of the following gases is having the widest explosion limit (about 2 to 81% gas in gas-air mixture), rendering it the property of the most explosive gas ?
Acetylene
Presence of non-biodegradable substances, like alkyl benzene sulphonate (ABS) from the detergents in polluted water stream causes
persistent foam
Pick out the wrong statement.
The concentric layer in atmosphere which contains about 70% of the total mass of atmosphere and characterised by a steady decrease in temperature is called stratosphere.
Noise level audible to audience sitting in the 5th row from the stage during a large orchestra show corresponds to about __________ decibels.
135
If carbon monoxide content in atmospheric air exceeds __________ ppm, death is bound to occur
3000 (i.e. 0.3%)
Radioactive solid nuclear wastes are disposed off by
underground burial in concrete containers.
Growth of __________ is promoted by the presence of manganese in water.
micro-organisms
Average human body contains about __________ percent water by weight.
70
Smog is
a combination of smoke and fog.
Reingleman chart No. 2 corresponds to __________ percent black smoke.
40
__________ is the process of killing organism in water.
Disinfection
Which of the following is a manmade source of air pollution ?
Automobile exhaust.
Which is the most efficient dust removal equipment for removal of sub-micronic dust particles from blast furnace gas ?
Electrostatic precipitator
Insufficient washing of sand grains in a rapid sand filter causes
mud balls
Which of the following sources is responsible for maximum air pollution?
Automobiles exhaust.
Which of the following is the most efficient for removal of very finely divided suspended solids and colloidal matter from the polluted water stream ?
Chemical coagulation
In sewage treatment, its sedimentation is speeded up by commonly adding
lime
‘Safe limit’ called Threshold Limit Value (TLV) of carbon monoxide in atmospheric air is < 50 ppm. The main source of carbon monoxide pollutant in air is the
automobiles exhaust.
Inhalation of silica dust by human being causes
asphyxiation
both(b) & (c)
Which of the following air pollutants is not toxic to vegetation i.e., doesn’t cause vegetation damage ?
Carbon monoxide
A masonry structure built below ground level, where biochemical reaction takes place due to anaerobic bacteria is called
septic tank
A considerable part of the harmful ultraviolet radiation of the sum does not reach the earth surface, because of the fact that, there is a layer of __________ high above earth’s atmosphere, which absorbs it.
ozone
White smoke coming out of the chimney of a furnace indicates the use of
very high excess air.
TLV of NO2 & NO exposure for the human being is 5 & 25 ppm respectively. Prolonged exposure of human being to NO2 causes
bronchitis
A man exposed to excessive noise level in the working environment may suffer from
all (a), (b) & (c)
Sulphur dioxide present in the industrial chimney exhaust gases causes
all (a), (b) and (c).
Which of the following is a secondary air pollutant ?
Photochemical smog
Presence of __________ bacteria in water causes disease like typhoid.
pathogenic
CFC (chloro fluoro carbon) is very highly reactive in causing depletion of ozone layer in the atmosphere. Each atom of chlorine liberated from CFC is capable of decomposing __________ molecules of ozones.
10^5
Green house gases blanket/block the infrared radiation from earth’s surface to the atmosphere leading to its progressive warming up. Which of the following gases does not exhibit green house effect ?
SO^3
Fresh domestic sewage is __________ in color.
grey
The common pollutant generated in chlor-alkali industry and battery manufacture is
mercury
During sewage treatment, the sewage is subjected to __________ treatment in Imhoff tank
both (b) and (c)
Black smoke coming out of the chimney of a furnace is an indication of the use of __________ in the furnace.
low amount of excess combustion air
__________ content of the phosphate rock is the pollutant of primary interest in a phos-phatic fertilizer plant.
Fluorine
Reingleman chart is used for the evaluation of __________ pollution.
air
Maximum permissible concentration (i.e. TLV) of DDT in public water supply system is __________ micro gram (μ g)/litre.
42
Brown spots in fabrics will be caused by washing with water containing large amount of .
iron
Deaeration of high pressure boiler feed water is done to reduce
its dissolved oxygen content
Exposure to SO2 containing chimney gases results in the
all (a), (b)and(c).
Pick out the wrong statement pertaining to ‘green house’ for the plants
Green house’ is colder than the outside atmosphere.
The detrimental effect on organism and water quality with temperature rise of aquatic system is the reduction of __________ of water.
dissolved oxygen content
Presence of iron and manganese in water causes
discoloration of bathroom fixtures.
Septic tanks are used for the __________ of the deposited solids.
anaerobic decomposition
Which of the following acts as a natural source of air pollution ?
Volcanic eruption
Death may occur, when SO2 concentration in atmospheric air exceeds __________ ppm
400
Higher concentration of CO2 in atmosphere
all (a), (b) and (c).
Radioactive substances present in the polluted water stream can be removed by
adsorption in ion exchange materials
In the context of the chemical process industries, the term BOD is normally associated with the
characterization of liquid effluents.
Noise emitted by a ventilation fan at a distance of 3 metres is about __________ decibels.
105
Which of the following is a green house gas other than CO2 ?
All (a), (b) and (c)
Inhalation of silica dust causes a disease called
silicosis
Automobile exhaust is passed through two compartments catalytic converter employing platinum as catalyst for
all (a), (b) and (c).
Lagooning process is mainly a means of the
sludge disposal
Pollution by particulate matter emission in the atmosphere does not take place during metal
polishing
Carbon monoxide is a pollutant, which causes
asphyxiation (suffocation) leading to death.
Direct reaction of unsaturated hydrocarbons with either NO or NO2 produces an eye irritating pollutant compound known as
peroxy acetyl nitrate (PAN) or methyl nitrile.
Presence of a certain minimum quantity of fluorine is desirable in potable water to prevent
dental cavities
Which of the following is not an air pollutant ?
Ozone
Algae growth in water is controlled by
chlorination
__________ is removed from water by lime-soda process.
Temporary hardness
Which of the following is the most major constituents of air pollutants ?
Oxides of sulphur
Most of the bacteria in sewage are
saprophytic
__________ is the process of killing organism in water.
Disinfection
Reingleman chart No. 2 corresponds to __________ percent black smoke.
40
manmade source of air pollution
Automobile exhaust
most efficient dust removal equipment for removal of sub-micronic dust particles from blast furnace gas
Electrostatic precipitator
Insufficient washing of sand grains in a rapid sand filter causes
mud balls
In sewage treatment, its sedimentation is speeded up by commonly adding
lime
most efficient for removal of very finely divided suspended solids and colloidal matter from the polluted water stream
Chemical coagulation
sources is responsible for maximum air pollution
Automobiles exhaust
secondary air pollutant
Photochemical smog
CFC (chloro fluoro carbon) is very highly reactive in causing depletion of ozone layer in the atmosphere. Each atom of chlorine liberated from CFC is capable of decomposing __________ molecules of ozones.
10^5
A ‘body’ which allows the short wavelength incoming solar radiation to enter in, but does not allow long wave length outgoing infra red radiation to escape out is called the
green house
Fresh domestic sewage is __________ in color.
grey
Black smoke coming out of the chimney of a furnace is an indication of the use of __________ in the furnace.
low amount of excess combustion air
Pick out the wrong statement
A bag filter incurs very small pressure drop and is very efficient for removal of sub-micronic dust particles from flue gases at very high temperature.
Beyond what concentration of H2S in air, acute danger to human life exists ?
700 ppm
__________ content of the phosphate rock is the pollutant of primary interest in a phos-phatic fertiliser plant.
Fluorine
Maximum permissible concentration (i.e. TLV) of DDT in public water supply system is __________ micro gram (μ g)/litre.
42
Reingleman chart is used for the evaluation of __________ pollution.
air
There are five concentric layers within the atmosphere which is differentiated on the basis of temperature. The atmospheric layer which lies close to the earth’s surface in which human being along with other organisms live is called troposphere. The rate at which air temperature in the troposphere gradually decreases with height is about __________ °C/km.
6.5
