Description : The Brake Horse power of the motor (efficiency 60%) required for a pump of capacity 0.075 cumec for a total lift of 12 m, is A. 10 B. 15 C. 20 D. 25 Q No: 44 Aerobic bacterias A. ... presence of free oxygen B. Consume organic matter as their food C. Oxidise organic matter in sewage D. All the above
Last Answer : ANS: D
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
Last Answer : ANS: A
Description : (2) amount of oxygen used for biochemical oxidation Explanation: Biochemical oxygen demand or B.O.D. is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to ... quantitative test, although it is widely used as an indication of the organic quality of water.
Last Answer : The addition of gypsum to port-land cement helps in : (1) increasing the strength of cement (2) rapid setting of cement (3) preventing rapid setting of cement (4) reduction in the cost of cement
Description : Pick up the correct statement from the following: A. Hydrogen sulphide gas in excess, may cause corrosion of concrete sewers B. 4 ppm of Dissolved Oxygen (D.O.) is ensured before discharging the treated ... river C. Solubility of oxygen in sewage is 95% of that of distilled water D. All the above
Description : The sewage treatment in septic tanks is due to A. Anaerobic decomposition B. Aerobic decomposition C. Parasitic decomposition 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
Last Answer : ANS: B
Description : Pick up the correct statement from the following: A. In treated sewage, 4 ppm of D.O. is essential B. Only very fresh sewage contains some dissolved oxygen C. The solubility of oxygen in sewage is 95% that is in distilled water D. All the above
Description : Bio-chemical oxygen demand (BOD) for the first 20 days in generally referred to A. Initial demand B. First stage demand C. Carbonaceous demand D. All of these
Description : If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is A. 100 mg/l B. 200 mg/l C. 300 mg/l D. 400 mg/l
Description : The factor responsible for purification of sewage in river is A. Hydrology B. Dissolved oxygen in water C. Temperature D. All the above
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 domestic sewage in large cities (a) has a high BOD as it contains both aerobic and anaerobic bacteria (b) is processed by aerobic and then anaerobic bacteria in the secondary treatment in ... sewage contains adequate oxygen (d) has very high amount of suspended solids and dissolved salts.
Last Answer : (b) is processed by aerobic and then anaerobic bacteria in the secondary treatment in Sewage Treatment Plants (STPs)
Description : Pick up the correct statement from the following: A. Indore method of composting involves decomposition under aerobic conditions B. Bangalore method of composting involves decomposing under anaerobic conditions C ... the Bangalore method of compositing is a powdery mass called humus D. all of these
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 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 : Aerobic activity is maximum A. In freshly produced sewage B. At sewer pipes C. In sewer treatment plants D. None of these
Description : Pathogens (or pathogenic bacterias) in water may cause A. Typhoid B. Cholera C. Dysentery D. All the above
Description : If the depletion of oxygen is found to be 2.5 mg/litre after incubating 2.5 ml of sewage diluted to 250 ml for 5 days at 20°C, B.O.D. of the sewage is A. 50 mg/l B. 100 mg/l C. 150 mg/l D. 250 mg/l
Description : If the depletion of oxygen is found to be 5 ppm after incubating a 2.5% solution of sewage sample for 5 days at 21°C, B.O.D. of the sewage is A. 50 ppm B. 100 ppm C. 150 ppm D. 200 ppm
Description : If 2% solution of a sewage sample is incubated for 5 days at 20°C and depletion of oxygen was found to be 5 ppm, B.O.D. of the sewage is A. 200 ppm B. 225 ppm C. 250 ppm D. None of these
Description : Dried sewage after treatment is used as A. Fertilizer B. Building material C. Chemical for lowering B.O.D. D. Base material for paints
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 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 : Pick out the wrong statement. (A) Biological oxygen demand (BOD) is a characteristic and not a constituent of water (B) BOD is a measure of the amount of oxygen which will be demanded & used in 5 days ... BOD is expressed in mg/litre (typically, BOD=2.5 mg/litre for potable water) (D) None of these
Last Answer : (D) None of these
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 : Chlorination of water is done for the removal of A. Bacterias B. Suspended solids C. Sediments D. Hardness
Description : If D.O. concentration falls down to zero in any natural drainage, it indicates the zone of A. Degradation B. Active decomposition C. Recovery D. Cleaner water
Description : Bacterias which can survive with or without free oxygen, are known (A) Aerobic bacterias (B) Anaerobic bacterias (C) Facultative bacterias (D) None of these
Last Answer : (C) Facultative bacterias
Description : Pick up the correct statement from the following: A. Anaerobic bacteria flourish in the absence of oxygen B. Aerobic bacteria flourish in the presence of oxygen C. Facultative bacteria flourish with or without oxygen D. All the above
Description : For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed A. 3 ppm B. 4 ppm C. 5 ppm D. 10 ppm
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 : A five day B.O.D. at 15°C of the sewage of a town is 100 kg/day. If the 5 day B.O.D. per head at 15°C for standard sewage is 0.1 kg/day, the population equivalent is A. 100 B. 1000 C. 5000 D. 10000
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 : The bacterias which may survive with or without free oxygen, are called (A) Aerobic bacterias (B) Anaerobic bacterias (C) Facultative bacteria's (D) None of these
Last Answer : (C) Facultative bacteria's
Description : The bacterias which require free oxygen for their survival, are called (A) Aerobic bacterias (B) Anaerobic bacterias (C) Facultative bacteria (D) None of these
Last Answer : (A) Aerobic bacterias
Description : Sunlight (A) Helps growth of bacterias (B) Impedes growth of algae (C) Increases dissolved oxygen content (D) Reduces turb
Last Answer : (B) Impedes growth of algae
Description : Removal of oil and grease from sewage, is known A. Screening B. Skimming C. Filtration D. None of these
Description : WASTE WATER ENGINEERING Objective Questions with Answers Q No: 161 The quantity of liquid waste which flows in sewers during the period of rainfall, is known A. Sanitary sewage B. Industrial waste C. Storm sewage D. None of these
Description : 54 Pick up the correct statement from the following: A. The ratio of the quantity of the diluting water to that of the sewage, is known as dilution factor B. The automatic purification of polluted ... phenomenon C. The photosynthesis is carried out in the presence of sun light D. All the above
Description : The detrimental effect on organism and water quality with temperature rise of aquatic system is the reduction of __________ of water. (A) Dissolved oxygen content (B) Biological oxygen demand (C) Vapor pressure (D) All (A), (B) and (C)
Last Answer : (A) Dissolved oxygen content
Description : Drained sewage has biological oxygen demand `(BOD)`:
Last Answer : Drained sewage has biological oxygen demand `(BOD)`: A. More than that of water B. Less than that of ... equal to that of water D. None of the above
Description : The ratio of oxygen available to the oxygen required for stabilisation of sewage is called the (A) Bacterial stability factor (B) Relative stability (C) Biological oxygen demand (BOD) (D) Oxygen ion concentration
Last Answer : (B) Relative stability
Description : Use of chlorine in the treatment of sewage (A) Helps in grease separation (B) Increases the biological oxygen demand (BOD) (C) Causes bulking of activated sludge (D) Aids in flocculation
Last Answer : (A) Helps in grease separation
Description : 5 days-biochemical oxygen demand (BOD5) is taken at a temperature of A. 0°C B. 15°C C. 20°C D. 25°C
Description : Pick out the wrong statement. (A) Biological oxygen demand (B.O.D.) value of a sewerage sample is always lower than its chemical oxygen demand (C.O.D.) value (B) Environmental pollution by ... in but does not allow the short wavelength infra red radiation to escape out of the earth's atmosphere
Last Answer : (D) The characteristic of a green house body is that it allows the long wavelength incoming solar radiation to come in but does not allow the short wavelength infra red radiation to escape out of the earth's atmosphere
Description : Aerobic biological oxidation ponds used for the purification of polluted water (A) Destroys/removes pathogen from the sewage (B) Is not very effective for non-biodegradable substances (e.g. ABS) containing effluents (C) ... much more effectively if the sewage is chlorinated (D) All (A), (B) & (C)
Last Answer : (D) All (A), (B) & (C)
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 algae dies out in the zone of A. Degradation B. Active decomposition C. Recovery D. Cleaner water
Description : Imhoff cone is used to determine A. Settleable solids B. Suspended solids C. Dissolved solids D. None of these
Description : The effluent of a septic tank is A. Fit for discharge into any open drain B. Foul and contains dissolved and suspended solids C. As good as that from a complete treatment D. None of these