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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
As per the world health organisation (WHO) specification, the maximum permissible concentration (
i.e., TLV) of particulate matter in air is __________ μg/m3.(μg-microgram)
Reinglemann chart is used for the measurement of the
exhaust gas density.
combustibles present in automobile exhaust.
smoke density from a chimey.
flue gas temperature.
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.
Main pollutant present in automobile exhaust is
Most of the atmospheric air pollutants are present in large quantity in
Which of the following is the most major constituents of air pollutants
Oxides of sulphur
oxides of nitrogen
In water treatment plant, zeolite process is used to remove the __________ of water
iron & zinc
Which of the following dust collection equipments is the least efficient (for sub-micronic particles)
Hollow wet scrubber
Dust catcher (gravity type)
The Killer gas which caused Bhopal gas tragedy in 1984 was
methyl iso-cynate (MIC)
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
TLV of aldrin in public water supply system is about __________ μg/litre
The term Biological Oxygen Demand
(BOD) is used in relation to
Lagooning process is mainly a means of the
reduction of excessive flow in sewers.
biological treatment of wastes.
None of these.
Which of the following is the most widely used disinfectant in water treatment
Irradiation of water by ultraviolet light
Algae growth in water is controlled by
Solid content in most of the domestic sewage is about __________ percent
Growth of __________ is promoted by the presence of manganese in water
'Safe limit' called Threshold Limit Value (TLV) of carbon monoxide in atmospheric air is < 50ppm.
The main source of carbon monoxide pollutant in air is the
photochemical reaction in polluted atmosphere.
burning of domestic fuel.
industrial chimney exhaust.
The pH value of potable water should be between
6.5 to 8
1 to 1.5
4 to 5
13 to 14
Fresh sewage is __________ in nature
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
Biological oxidation pond
Aerobic biological oxidation ponds used for the purification of polluted water
destroys/removes pathogen from the sewage.
is not very effective for nonbiodegradable substances (e.g. ABS) containing effluents.
destroys/removes pathogen much more effectively if the sewage is chlorinated.
all (a), (b) & (c).
The amount of chemical coagulant added for treatment of polluted water __________ with increase in temperature of the polluted water to be treated
may increase or decrease ; depends on the chemical characteristics of polluted water.
Waste/polluted water discharged from electroplating, blast furnace and coal mining industries contain mainly __________ substances
NONE OF THESE
Presence of __________ hardness is responsible for the temporary hardness in water
Scale formation in boiler is controlled by
keeping the pH value of feed water just below 7.
preheating of feed water.
reduction in hardness, silica & alumina in feed water.
eliminating H2S in feed water.
Carbonaceous particles having size less than 1 μm are called
Permissible safe limit (TLV) of __________ toxic gas is 100-1000 parts per million (ppm)
Irradiation of water by ultraviolet light of suitable wavelength is commonly used for disinfection of water in
municipal sewage treatment.
iron & steel plant.