Chemical Environmental Engineering Archives | Page 25 of 27

High noise levels produced during operation of fans and compressors can be reduced by using__________________?

August 29, 2021March 11, 2019 by admin

High noise levels produced during operation of fans and compressors can be reduced by using__________________?

A. Mufflers (silencers)
B. Acoustic absorbent
C. Lagging of noisy duct
D. None of these

August 29, 2021March 11, 2019 by admin

Salt content in sea water is about ______________ percent?

A. 0.5
B. 1
C. 3.5
D. 9.05

August 29, 2021March 11, 2019 by admin

______________ is the process of killing organism in water ?

A. Coagulation
B. Sterilisation
C. Disinfection
D. Sedimentation

August 29, 2021March 11, 2019 by admin

Fresh sewage is ______________ in nature?

A. Acidic
B. Neutral
C. Alkaline
D. Highly acidic

August 29, 2021March 11, 2019 by admin

From pollution control point of view, the maximum permissible concentration of sulphur dioxide in atmospheric air is about ________________ ppm?

A. 5
B. 50
C. 500
D. 5000

August 29, 2021March 11, 2019 by admin

Maximum permissible concentration (i.e. TLV) of DDT in public water supply system is _______________ micro gram (μ g)/litre?

A. 22
B. 42
C. 332
D. 1050

August 29, 2021March 11, 2019 by admin

Which of the following fine dust removal equipments is the most efficient ?

A. Bag filter
B. Scrubber
C. Electrostatic precipitator
D. Cyclone separator

August 29, 2021March 11, 2019 by admin

Noise level in a quiet private business office is about _____________ decibels?

A. 25
B. 50
C. 70
D. 85

August 29, 2021March 11, 2019 by admin

Which of the following is not a weightless pollutant ?

A. SPM
B. Thermal pollution
C. Radioactive rays
D. Noise pollution

August 29, 2021March 11, 2019 by admin

Noise pollution level in a chemical plant is expressed in __________________?

A. Roentgen
B. Decibel
C. Hertz
D. None of these