Chemical Engineering :: Environmental Engineering
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The maximum permissible noise level to which a man working in a chemical plant can be exposed for eight hours per day is about __________ decibels.
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The most commonly used chemical coagulant in water treatment is
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The biological decomposition of organic substances in wastes controlled conditions is called
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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
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Smog is not formed due to the presence of __________ in the atmosphere.
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Pick out the correct statement.
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Which of the following is not a source of ozone emission in the atmosphere ?
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Oceans act as sinks for atmospheric gases including carbon dioxide whose concentration in the atmosphere is increased by the
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Pick out the correct statement.
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The upper layer of atmosphere is called the
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A.
Chemical oxygen demand (COD) is a measure of chemically oxidisable organic matter present in water.
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B.
COD is determined by oxidising the organic matter present in water with potassium dichromate in cone, sulphuric acid solution at boiling temperature for specified time.
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C.
COD is related to BOD of a given waste in water but the relationship varies for different wastes. Typically COD of potable water may be 1-2 mg/litre.
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D.
all (a), (b) and (c).
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