Description : Dilution method of disposing of sewage, is not preferred to A. When sewage is fresh B. When diluting water has high dissolved oxygen content C. When diluting water is used for water supply near the point of sewage disposed D. When the diluting water is having flow currents
Last Answer : ANS: C
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 : 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 : Before discharging the foul sewage into rivers, it is generally treated by A. Screening B. Sedimentation C. Oxidation D. All the above
Last Answer : ANS: D
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 : In very first stage of decomposition of the organic matter in sewage A. Nitrites are formed B. Nitrates are formed C. Carbondioxide is formed D. Ammonia is formed
Description : The term "Doab" means – (1) a land between two mountains (2) a land between two lakes (3) a land between two rivers (4) a land between two seas
Last Answer : (3) a land between two rivers Explanation: Doab is a term used in India and Pakistan for the "tongue," or tract of land lying between two converging, or confluent, rivers. It is similar to an ... to the confluence of two rivers (esp. that between the Ganges and Jumna). Physical Geography (Set: 04)
Description : The term “Doab” means (1) a land between two mountains (2) a land between two lakes (3) a land between two rivers (4) a land between two seas
Last Answer : a land between two rivers
Description : Before discharging the foul sewage into rivers, it is generally treated by (a) screening (b) sedimentation (c) Oxidation (d) sludge digestion and disinfection (e) all the above*
Last Answer : e) all the above*
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 : 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
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 : The rate of accumulation of sludge per person per year, is A. 10 litres B. 15 litres C. 20 litres D. 25 litres
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 : In normal conditions, the period for sludge digestion, is A. 10 days B. 20 days C. 30 days D. 60 days
Description : In a sludge tank, the gas mainly produced, is A. Oxygen B. Nitrogen C. Hydrogen D. Carbon dioxide
Description : The moisture content of sludge is reduced from 90% to 80% in a sludge digestion tank. The percentage decrease in the volume of sludge, is A. 25 % B. 50 % C. 10 % D. 5 %
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 : 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 : 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
Description : The sludge does not contain waste water from A. Bath rooms B. Wash basins C. Kitchen sinks D. Toilets
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 : 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 : 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 : In 1000 kg of sewage, the total solids approximate A. 0.5 to 1.0 kg B. 1 kg to 2.0 kg C. 5 kg to 7.5 kg D. 7.5 kg to 10 kg
Description : Aerobic activity is maximum A. In freshly produced sewage B. At sewer pipes C. In sewer treatment plants D. None of these
Description : To test chemical oxygen demand (C.O.D.) of sewage, organic matter is oxidised by potassium dichromate in the presence of A. Hydrochloric acid B. Sulphuric acid C. Nitric acid D. Citric acid
Description : The sewer which transports the sewage to the point of treatment, is called A. House sewer B. Out-fall sewer C. Branch sewer D. Main sewer
Description : During purification process of sewage the gas given off, is A. Carbon dioxide B. Hydrogen C. Ammonia D. All the above
Description : In sewage, the solids in mg per litre is A. 100 to 500 B. 500 to 1000 C. 1000 to 1500 D. 1500 to 2000
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
Description : Fresh sewage may become stale in A. One hour B. Two to three hours C. Three to four hours D. Six hours
Description : Rate of flow of sewage is generally assumed A. More than the rate of water supply B. Equal to the rate of water supply C. Less than the rate of water supply D. At 150 litres per capita
Description : Removal of oil and grease from sewage, is known A. Screening B. Skimming C. Filtration D. None of these
Description : The ratio of minimum hourly flow to the average flow of sewage is A. 1/4 B. 1/3 C. 1/2 D. 3/4
Description : Q No: 291 The coagulant widely used for sewage treatment, is A. Alum B. Ferric chloride C. Ferric sulphate D. Chlorinated copperas
Description : The sewer pipe which carries sewage from a building for immediate disposal is A. House sewer B. Lateral sewer C. Intercepting sewer D. Main sewer
Description : When drainage to sewage ratio is 20, the peak dry weather flow is A. 20% of the design discharge B. Slightly less than 5% of the design discharge C. Slightly more than 5% of the design discharge D. None of these
Description : The non-clog pump which permits solid matter to pass out with the liquid sewage, is A. Centrifugal pump B. Reciprocating pump C. Pneumatic ejector D. None of these
Description : Q No: 271 Pick up the correct statement from the following: A. Turbidity is more in strong sewage B. The black colour indicates septic sewage C. The sewage omits offensive odours after four hours D. All the above
Description : The sewage is pumped up A. From low lying areas B. From flat areas C. From basements D. All the above
Description : In sewage having fully oxidised organic matter, the nitrogen exists in the form of A. Nitrites B. Nitrates C. Free ammonia D. Aluminoid nitrogen
Description : Dry water flow in a combined sewer, is A. Industrial sewage B. Domestic sewage C. Storm water D. Inclusive of domestic and industrial sewage but excludes storm water
Description : The presence of free ammonia in sewage, is detected by A. Boiling B. Adding potassium permanganate C. Adding sulphuric acid D. Phenol-di-sulphuric acid
Description : 3.0 ml of raw sewage is diluted to 300 ml. The D.O. concentration of the diluted sample at the beginning of the test was 8 mg/l. After 5 dayincubation at 20°C, the D.O. concentration was 5 mg/l. The BOD of raw sewerage is A. 100 mg/l B. 200 mg/l C. 300 mg/l D. 400 mg/l
Description : Disposal to sewage in large cities, is done in A. Irrigation B. Dilution C. Oxidation D. Purification
Description : The dimensions of a rectangular settling tank are: length 24 m, width 6 m and depth 3 m. If 2 hour detention period for tanks is recommended, the rate of flow of sewage per hour, is A. 204 cu.m B. 208 cu.m C. 212 cu.m D. 216 cu.m
Description : The sewage treatment in septic tanks is due to A. Anaerobic decomposition B. Aerobic decomposition C. Parasitic decomposition D. None of these