18351. Lagoons used for purification of polluted water
18352. The principal gas evolved from sludge digestion tank is
18353. There are thirteen metals which are treated as pollutants. Which of the following metals is not a pollutant ?
18354. The function of skimming tank in sewage treatment is to remove __________ substances.
18355. The weakest sound that can be heard by a person in a quiet environment is equivalent to __________ decibel.
18356. Inorganic impurities causing water pollution is
18357. The main type of sludge gas evolved during sewage treatment in Imhoff tank is
18358. From pollution control point of view, the maximum permissible concentration of sulphur dioxide in atmospheric air is about __________ ppm.
18359. The pH value of oxidised sewage is about
18360. Smog is
18361. __________ is the process of killing organism in water.
18362. Reingleman chart No. 2 corresponds to __________ percent black smoke.
18363. Which of the following is a manmade source of air pollution ?
18364. Which is the most efficient dust removal equipment for removal of sub-micronic dust particles from blast furnace gas ?
18365. Insufficient washing of sand grains in a rapid sand filter causes
18366. Which of the following sources is responsible for maximum air pollution ?
18367. Which of the following is the most efficient for removal of very finely divided suspended solids and colloidal matter from the polluted water stream ?
18368. In sewage treatment, its sedimentation is speeded up by commonly adding
18369. Noise level in a quiet private business office is about __________ decibels.
18370. '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
18371. Inhalation of silica dust by human being causes
18372. Which of the following air pollutants is not toxic to vegetation i.e., doesn't cause vegetation damage ?
18373. A masonry structure built below ground level, where biochemical reaction takes place due to anaerobic bacteria is called
18374. 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.
18375. White smoke coming out of the chimney of a furnace indicates the use of
18376. TLV of NO2 & NO exposure for the human being is 5 & 25 ppm respectively. Prolonged exposure of human being to NO2 causes
18377. Sulphur dioxide present in the industrial chimney exhaust gases causes
18378. A man exposed to excessive noise level in the working environment may suffer from
18379. Which of the following is a secondary air pollutant ?
18380. Presence of __________ bacteria in water causes disease like typhoid.
18381. 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.
18382. 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 ?
18383. 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
18384. Fresh domestic sewage is __________ in color.
18385. The common pollutant generated in chlor-alkali industry and battery manufacture is
18386. During sewage treatment, the sewage is subjected to __________ treatment in Imhoff tank.
18387. Black smoke coming out of the chimney of a furnace is an indication of the use of __________ in the furnace.
18388. Bread is related to wheat in the same way as Brick is related to?
18389. __________ content of the phosphate rock is the pollutant of primary interest in a phos-phatic fertiliser plant.
18390. Beyond what concentration of H2S in air, acute danger to human life exists ?
18391. Reingleman chart is used for the evaluation of __________ pollution.
18392. ശ്രീ ബുദ്ധന്റെ യഥാര്ത്ഥ നാമം? [Shree buddhanre yathaarththa naamam?]
18393. 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.
18394. Brown spots in fabrics will be caused by washing with water containing large amount of .
18395. Maximum permissible concentration (i.e. TLV) of DDT in public water supply system is __________ micro gram (μ g)/litre.
18396. Sooty and sulphurous smog formed due to combustion of fossil fuels particularly in winter, continues throughout the day and night. When the moist atmospheric air's water vapor condenses on the solid particles of smoke thereby forming smog (smoke + fog), it causes
18397. Deaeration of high pressure boiler feed water is done to reduce
18398. Exposure to SO2 containing chimney gases results in the
18399. The detrimental effect on organism and water quality with temperature rise of aquatic system is the reduction of __________ of water.
18400. Hydrogen ion concentration in distilled water is