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