Description : Q No: 251 In a sludge digestion tank if the moisture content of sludge V1 litres is reduced from p1 % to p2 % the volume V2 is A. [(100 + P1)/(100 – P2)] V1 B. [(100 – P1)/(100 + P2)] V1 C. [(100 – P1)/(100 – P2)] V1 D. [(100 + P2)/(100 – P1)] V1
Last Answer : ANS: C
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 : 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%
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 : In normal conditions, the period for sludge digestion, is A. 10 days B. 20 days C. 30 days D. 60 days
Description : The first stage of neutral process of sludge digestion, is A. Acid fermentation B. Acid regression C. Alkaline fermentation D. None of these
Last Answer : ANS: A
Description : Pick up the correct statement from the following: A. Rate of digestion of sludge is more at higher temperature B. Thermophilic organisms digest the sludge if the temperature ranges from 40° to 60°C C. Mesophilic organisms digest the sludge if the temperature is between 25° and 40°C D. All the above
Last Answer : ANS: D
Description : 11. Acid regression stage of sludge digestion at a temperature 21°C extends over a period of A. 15 days B. 30 days C. 60 days D. 90 days
Description : The detention time (t) of a settling tank, may be defined as the time required for A. A particle to travel along its length B. A particle to travel from top surface to bottom sludge zone C. The flow of sewage to fill the tank D. None of these
Description : In a sludge tank, the gas mainly produced, is A. Oxygen B. Nitrogen C. Hydrogen D. Carbon dioxide
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
Description : The rate of accumulation of sludge per person per year, is A. 10 litres B. 15 litres C. 20 litres D. 25 litres
Description : Due to a rise in temperature, the viscosity and the unit weight of the percolating fluid are reduced to 60% and 90% respectively. If other things remain constant, the coefficient of permeability (A) Increases by 25 % (B) Increases by 50 % (C) Increases by 33.3 % (D) Decreases by 33.3 %
Last Answer : (B) Increases by 50 %
Description : The rate of accumulation of sludge in septic tanks is recommended as A. 30 litres/person/year B. 25 litres/person/year C. 30 litres/person/month D. 25 litres/person/month
Description : For design of sewers, percentage of sewage discharge is assumed A. 65 to 70% B. 70 to 75% C. 75 to 80% D. 85%
Description : Seed germination percentage of rough lemon is: a. 50-60% b. 60-70% c. 70-80% d. 80-90%
Last Answer : 60-70%
Description : Germination percentage in sour orange rootstock is: a. 50-60% b. 61-70% c. 71-80% d. 81-90%
Last Answer : 50-60%
Description : The sum of the percentage of tricalcium silicate and dicalcium silicate for Portland cement varies from. (a) 50 to 60% (b) 60 to 70% (c) 70 to 80% (d) 80 to 90%
Last Answer : (c) 70 to 80%
Description : The digested sludge from septic tanks, is removed after a maximum period of A. 3 years B. 3.5 years C. 4 years D. 5 years
Description : Water content of sewage is about A. 90 % B. 95 % C. 99 % D. 9.9 %
Description : Sludge banks are formed if sewage is disposed of in A. Rivers B. Seas C. Lakes D. None of these
Last Answer : ANS: B
Description : pH value of sludge during alkaline regression stage, is A. More than 7 B. Less than 7 C. Less than 6 D. More than 6
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 : Skimming tanks are A. Used to remove the grease and oil B. Those from which sludge is skimmed out C. Tanks provided with self- cleansing screens D. Improved version of grit chambers
Description : The sludge does not contain waste water from A. Bath rooms B. Wash basins C. Kitchen sinks D. Toilets
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
Description : The principal gas evolved from sludge digestion tank is (A) CO (B) CO2 (C) CH4 (D) N2
Last Answer : (C) CH4
Description : In R.C. sewer pipes, the percentage longitudinal reinforcement to the cross-sectional area of concrete is kept A. 10.0 B. 5.0 C. 2.0 D. 0.25
Description : Percentage of pozzolanic material containing clay upto 80% used for the manufacture of pozzolana cement, is (A) 30 % (B) 40 % (C) 50 % (D) 60 %
Last Answer : (A) 30 %
Description : The density of population over 40 hectares is 250/hectare. If water supply demand per day is 200 litres and sewage discharge is 80% of water supply, the sewage flow in sewers of separate system, is A. 0.05552 cumec B. 0.05554 cumec C. 0.05556 cumec D. 0.0556 cumec
Description : In a liquid limit test, the moisture content at 10 blows was 70% and that at 100 blows was 20%. The liquid limit of the soil, is (A) 35 % (B) 50 % (C) 65 % (D) None of these
Last Answer : Answer: Option C
Description : The normal values of over flow rates for secondary sedimentation tanks, ranges between A. 25,000 to 35,000 litres/sqm/day B. 40,000 to 50,000 litres/sqm/day C. 50,000 to 60,000 litres/sqm/day D. 80,000 to 10,000 litres/sqm/day
Description : Which of the following percentage of foreign exchange earnings can be credited to the EEFC account? A. 80% B. 90% C. 75% D. 95% E. 100%
Last Answer : E. 100% Explanation: under EEFC account, a facility provided to the foreign exchange earners, including exporters, to credit 100 per cent of their foreign exchange earnings to the account. ... have to convert foreign exchange into Rupees and vice versa, thereby minimizing the transaction costs.
Description : What percentage of the human body is composed of water? a. 50% b. 80% c. 90%
Last Answer : B. 80%
Description : Approximately how many businesses content marketing is used? A. 20% to 30% B. 40% to 50% C. 60% to 70% D. 80% to 90%
Last Answer : D. 80% to 90%
Description : In Portland Blast furnace slag cement, the blast furnace slag content shall not exceed [ A ] 50% [ B ] 65% [ C ] 80% [ D ] 90%
Last Answer : [ B ] 65%
Description : The practical limit of moisture content achieved in air drying of timber is (A) 5 % (B) 15 % (C) 25 % (D) 35 %
Last Answer : Answer: Option B
Description : For determining the moisture content of a soil sample, the following data is available Weight of container = 260 g, Weight of soil sample and = 320 g container, Weight of soil sample (dried) and = 310 g container. The moisture content of the soil sample, is (A) 15 % (B) 18 % (C) 20 % (D) 25 %
Last Answer : (C) 20 %
Description : In a morse test for a 2 cylinder, 2 S SI engine, the brake power was 9 kW. Whereas the brake power of individual cylinders with spark cut off were 4.25 kW and 3.75 kW. The mecheffic of the engine is (a) 90% (b) 80% (c) 45.5% (d) 52.5%
Last Answer : Ans :a
Description : The reduced levels of the string at the consecutive sight rails A and B are 203.575 m, 203.475 m respectively. If the difference of their R.D.s is 10 m, the gradient of the sewer line is A. 1 in 100 upward B. 1 in 500 upward C. 1 in 100 downward D. 1 in 503 upward
Description : In primary sedimentation, the 0.2 mm inorganic solids get separated if specific gravity is A. 2.25 B. 2.50 C. 2.55 D. 2.65
Description : The angle subtended by the surface of sewer water with partial flow, at sewer centre is 120°, the depth of sewerage is A. 20 cm B. 25 cm C. 40 cm D. 50 cm
Description : Inter-distance between ventilation columns in a sewer line is kept A. 25 to 50 m B. 50 m to 100 m C. 100 m to 150 m D. 150 m to 300 m
Description : The normal value of over flow rates for plain primary sedimentation tanks, ranges between A. 25,000 to 35,000 litres/sqm/day B. 40,000 to 50,000 litres/sqm/day C. 50,000 to 60,000 litres/sqm/day D. 80,000 to 100,000 litres/sqm/day
Description : The normal values of over flow rates for sedimentation tanks using coagulant, ranges between A. 25,000 to 35,000 litres/sqm/day B. 40,000 to 50,000 litres/sqm/day C. 50,000 to 60,000 litres/sqm/day D. 80,000 to 100,000 litres/sqm/day
Description : The width of a settling tank with 2 hour detention period for treating sewage 378 cu m per hour, is A. 5 m B. 5.5 m C. 6.5 m D. 7 m
Description : Which one of the following statements regarding septic tanks is wrong? A. A gap of 7.5 cm between the bottom of the covering slab and the top level of scum is provided B. The outlet invert level is kept ... . The minimum width of septic level is 90 cm D. The depth of tank is kept equal to its width
Description : For a continuous flow type of sedimentation tanks A. Width of the tank is normally kept about 6 m B. Length of the tank is normally kept 4 to 5 times the width C. Maximum horizontal flow velocity is limited to 0.3 m/minute D. All the above
Description : The steel mainly contains how much percentage of carbon a) 0.70 to 0.80% b) to 0.3 % c) 0.5 to 0.1 %
Last Answer : 0.70 to 0.80%
Description : The sewage discharge in a detritus tank of a treatment plant is 576 litres/sec with flow velocity of 0.2 m/sec. If the ratio of width to depth is 2, the depth is A. 100 cm B. 110 cm C. 120 cm D. 150 cm