Description : In trickling filter, B.O.D. is reduced to A. 30 to 40% B. 40 to 60% C. 60 to 80% D. 80 to 90%
Last Answer : ANS: C
Description : For treating the sewage of a large city, you will recommend A. A sedimentation tank and an activated sludge treatment plant B. A plant consisting of Imhoff tanks with low rate trickling filters C. Sedimentation tanks with high rate trickling filters D. None of these
Last Answer : ANS: A
Description : The sewage treatment units in which anaerobic decomposition of organic matter is used, are called A. Imhoff tanks B. Trickling filters C. Sludge sedimentation tanks D. None of these
Last Answer : ANS: B
Description : The type of bacteria which is active in trickling filter during biological treatment of sewage is the __________ bacteria. (A) Anaerobic (B) Saprophytic (C) Aerobic (D) Parasitic
Last Answer : (C) Aerobic
Description : The cake resistance increases steadily with the time of filtration in a plate and frame filter employing constant __________ filtration. (A) Rate (B) Pressure (C) Both (A) & (B) (D) Neither (A) nor (B
Last Answer : (C) Both (A) & (B)
Description : Filtration capacity of a rotary drum vacuum filter depends upon the (A) Cake thickness (B) Characteristics of the feed slurry (C) Both (A) & (B) (D) Neither (A) nor (B)
Description : With self cleansing velocity in sewers A. Silting occurs at bottom B. Scouring occurs at bottom C. Both silting and scouring occur at bottom D. Neither silting nor scouring occurs at bottom
Last Answer : ANS: D
Description : Facultative bacteria survive in A. The presence of oxygen B. The absence of oxygen C. Both cases A. and B. D. Neither A. nor B.
Description : In sewers designed with self cleansing velocity, A. The bottom is silted B. The bottom is scoured C. Both silting and scouring occur at the bottom D. Neither silting nor scouring occurs at the bottom
Description : The use of coarse screens for the disposal of sewage, may be dispensed with by A. Comminutor B. Shredder C. Both A. and B. D. Neither A. nor B.
Description : Maximum permissible velocity 1.5 m/sec, is adopted in drains A. With beds of rocks and gravels B. Lined with stones C. Both A. and B. D. Neither A. nor B.
Description : The grit and silt of the grit chambers, may not be used for A. Raising low lying areas by dumping B. Concreting C. Both A. and B. D. Neither A. nor B.
Description : For efficient working of a sewer, it must be ensured that A. Minimum velocity of 0.45 m/sec, is maintained at its minimum flow B. A maximum velocity of 0.90 m/sec, is maintained at its maximum flow C. Both A. and B. D. Neither A. nor B.
Description : Removal of oil and grease from sewage, is known A. Screening B. Skimming C. Filtration D. None of these
Description : The main pollutant in waste water discharged from a petroleum refinery is oil (both in free and emulsified form). Free oil is removed by (A) Biological oxygen pond (B) Aerated lagoons (C) Trickling filters (D) Gravity separator having oil skimming devices
Last Answer : (D) Gravity separator having oil skimming devices
Description : The temperature affects the A. Biological activity of bacteria in sewage B. Solubility of gases in sewage C. Viscosity of sewage D. All the above
Description : To maintain aerobic biological activity, the moisture content of the compost mass should be about A. 45 % B. 50 % C. 55 % D. 60 %
Description : The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known A. Bio-Chemical Oxygen Demand (B.O.D.) B. Dissolved Oxygen (D.O.) C. Chemical Oxygen Demand (C.O.D.) D. None of these
Description : High magnesia lime is added to hot sugar cane juice (during the manufacture of sugar) to (A) Flocculate the impurities (B) Facilitate fast filtration (C) Both (A) and (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) and (B)
Description : Self-cleansing velocity is A. Velocity at dry weather flow B. Velocity of water at flushing C. Velocity at which no accumulation remains in the drains D. Velocity of water in a pressure filter
Description : In the activated sludge process A. Aeration is continued till stability B. Aeration is done with an admixture of previously aerated sludge C. Sludge is activated by constant stirring D. Water is removed by centrifugal action
Description : During waste water treatment, trickling filter is used for :
Last Answer : During waste water treatment, trickling filter is used for : A. Primary treatements B. ... C. Secondary anaerobic treatement D. Tertiary treatement
Description : The filter over which sewage is sprinkled is called as – (1) Trickling filter (2) Percolating filter (3) Contact bed (4) Intermittent sand filter
Last Answer : (1) Trickling filter Explanation: A trickling filter, also known as percolating filter, is an artificial bed of stone or broken brick material over which waste water or sewage is allowed to sprinkle or to trickle. It is then collected through the under drainage system.
Description : Fine grit present in sewage is removed in the __________ during sewage treatment. (A) Grit chamber (B) Detritus tank (C) Trickling filter (D) Skimming tank
Last Answer : (B) Detritus tank
Description : Trickling filter comes under A- primary treatment B- secondary treatment C- tertiary treatment D- none of these
Last Answer : secondary treatment
Description : The filter over which sewage is sprinkled is called as (1) Trickling filter (2) Percolating filter (3) Contact bed (4) Intermittent sand filter
Last Answer : Trickling filter
Description : Eutrophication of a water body enhances – (1) Organic matter production (2) Biological oxygen demand (3) Both (1) and (2) (4) Neither (1) nor (2)
Last Answer : (3) Both (1) and (2) Explanation: Eutrophication is the ecosystem response to the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sew-age. It leads not only to increased levels of nutrients, but increased Biological Oxygen Demand as well.
Description : Biological oxidation ponds remove organic matters present in the polluted water by (A) Using the activities of bacteria and other micro organisms (B) Aerobic oxidation (C) Both (A) & (B) (D) Neither (A) nor (B)
Description : Eutrophication of a water body enhances (1) Organic matter production (2) Biological oxygen demand (3) Both (1) and (2) (4) Neither (1) nor (2)
Last Answer : Both (1) and (2)
Description : Traps A. Are water seals which prevent the entry of foul gases B. Are used to trap the rats entering sewers C. Dissolve the foul gases D. Create symphonic action to increase the quick disposal of sewerage
Description : The main process to purify water by filtration, is (A) Mechanical straining (B) Flocculation and sedimentation (C) Biological metabolism (D) All the above
Last Answer : (D) All the above
Description : Filter medium resistance is important during the __________ of filtration. (A) Early stages (B) Final stages (C) Entire process (D) None of these
Last Answer : (A) Early stages
Description : During purification process of sewage the gas given off, is A. Carbon dioxide B. Hydrogen C. Ammonia D. All the above
Description : Oxidation process results in the formation of A. Carbon dioxide B. Nitrates C. Sulphates D. All the above
Description : The first stage of neutral process of sludge digestion, is A. Acid fermentation B. Acid regression C. Alkaline fermentation D. None of these
Description : Pick up the correct statement from the following: A. The materials separated by screens, is called screenings B. The screenings are disposed off either by burning or by burial or by dumping C. The process of burning the screenings, is known as compositing D. All the above
Description : Pick up the incorrect statement from the following: A. The mixture of water and waste products, is called sewage B. The treated sewage effluents, are generally used for irrigating the ... is called sewerage D. The old convergence system was definitely better than water carried sewerage system
Description : Pick up the incorrect statement from the following: A. The process of decomposing the organic matter under controlled anaerobic conditions, is called sludge digestion B. Sludge digestion is carried ... contain 75% carbon dioxide D. The gases produced in sludge digestion process, contain 75% methane
Description : The damage/deterioration of metals by the __________ action of fluids is called 'erosion'. (A) Abrasive (B) Corrosive (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (A) Abrasive
Description : If the market share of a company is increasing 1. It is a sign of progress 2. The company must take the action to arrest the trend 3. both 1 & 2 4. neither 1 nor 2 5. None of these
Last Answer : It is a sign of progress
Description : If the market share of a company is increasing 1. It is a sign of progress 2. The company must take the action to arrest the trend 3. Both 1 & 2 4. Neither 1 nor 2 5. None of these
Description : Replenishment of dissolved oxygen in water stream polluted with industrial waste occurs by (A) Natural aeration of water stream (B) Photosynthetic action of algae (C) Both (A) & (B) (D) Neither (A) nor (B)
Description : Filtration should be stopped in a filter press, if the (A) Cake becomes very dense (B) Liquor stops flowing out to the discharge (C) Filtration pressure rises suddenly (D) Both (B) & (C
Last Answer : (D) Both (B) & (C
Description : Sewer pipes need be checked for A. Minimum flow B. Maximum flow C. Both A. and B. D. None of these
Description : In septic tanks, decomposition of organic bacteria, is done by A. Anaerobic bacteria B. Aerobic bacteria C. Both types of bacterias D. None of these
Description : Assertion A.: The minimum self cleansing velocity in the sewer, at least once a day, must be generated. Reason (R): If certain deposition takes place and is not removed, it obstructs free flow and causes further ... correct explanation of A C. A is true but R is false D. A is false but R is true
Description : Assertion A. : Discharging the effluents from the oxidation ponds just up stream of lakes or reservoirs is undesirable. Reason (R) : The discharged algae get settled in the reservoirs and cause anaerobic decomposition and other ... of A C. A is true but R is false D. A is false but R is true
Description : Large diameter sewers subjected to external pressure alone, are reinforced A. Near the inner surface of the pipe B. Near the outer surface of the pipe C. Both A. and B. D. With elliptical cage
Description : Assertion A.: A free board of 0.3 m is provided above the top sewage line in septic tanks. Reason (R): It helps to accommodate the scum in the septic tank. A. Both A and R is true and R is the correct ... is not a correct explanation of A C. A is true but R is false D. A is false but R is true
Description : Q No: 78 Hume steel pipes are A. Steel pipes B. Steel shell coated from inside with cement mortar C. Steel shell coated from outside with cement mortar D. Both B. and C.