Description : Primary treatment of sewage consists of removal of A. Large suspended organic solids B. Oil and grease C. Sand and girt D. Floating materials
Last Answer : ANS: A
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
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 : Pathogens (or pathogenic bacterias) in water may cause A. Typhoid B. Cholera C. Dysentery D. All the above
Last Answer : ANS: D
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
Last Answer : ANS: B
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
Description : Which is the most practical and economical method for removal of suspended solid matter from polluted water? (A) Sedimentation (B) Skimming off (C) Chlorination (D) Biological oxidation
Last Answer : (A) Sedimentation
Description : The porosity of sediments in sewer pipes, is usually taken as A. 0.010 B. 0.011 C. 0.012 D. 0.013
Description : Steam condensate is recovered by steam traps and recycled for use as boiler feed water, because of its low (A) Hardness (B) Dissolved solids content (C) Suspended solids content (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : Chemical coagulation of drinking water, is done (A) To settle suspended materials (B) To increase rate of settlement of suspended materials (C) To remove the bacterias (D) None of these
Last Answer : (B) To increase rate of settlement of suspended materials
Description : Aeration Of water is done to remove a) Odour* b) Colour c) Bacterias d) Hardness e) Turbidity
Last Answer : a) Odour*
Description : Coal washing waste water containing about 3% suspended solids (comprising of clay, slate, stone etc.) is treated for solid particles removal (A) By chemical coagulation (B) In sedimentation tanks equipped with mechanical scrapper (C) In vacuum filter (D) In clarifiers
Last Answer : (B) In sedimentation tanks equipped with mechanical scrapper
Description : Removal of __________ is accomplished by aeration of water. (A) Dissolved gases (B) Suspended solids (C) Dissolved solids (D) None of these
Last Answer : (A) Dissolved gases
Description : Which of the following is the most efficient for removal of very finely divided suspended solids and colloidal matter from the polluted waterstream? (A) Sedimentation tank (B) Circular clarifier (C) Mechanical flocculation (D) Chemical coagulation
Last Answer : (D) Chemical coagulation
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 : 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 : 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 : For evaporation and measurement of settable solids, the apparatus used, is A. A jar B. A breaker C. A test tube D. An Imhoff cone
Description : Imhoff cone is used to measure A. Total organic solids B. Total solids C. Total in organic solids D. Settleable solids
Description : Which of the following pumps in used to pump sewage solids with liquid sewage without clogging the pump is? A. Centrifugal pump B. Pneumatic ejector C. Reciprocating pump D. None of these
Description : Removal of oil and grease from sewage, is known A. Screening B. Skimming C. Filtration D. None of these
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 : If the grit in grit chambers is 4.5 million litres per day, its cleaning is done A. Manually B. Mechanically C. Hydraulically D. Electrically
Description : Disposal to sewage in large cities, is done in A. Irrigation B. Dilution C. Oxidation D. Purification
Description : The laying of sewers is done with A. Magnetic compass B. Theodolite C. Level D. Clinometer
Last Answer : ANS: C
Description : Lead acetate test in sewer manhole is done to test the presence of A. Methane gas B. Hydrogen sulphide C. Carbondioxide gas D. Diesel vapours
Description : The function of sedimentation tank in sewage treatment is to: (1) Disinfect the sewage (2) Remove water content (3) Aerate the sewage (4) Remove suspended solids
Last Answer : (4) Remove suspended solids Explanation: The function of sedimentation tank in the sewage treatment is to remove suspended solids.
Description : Presence of __________ in water stream are deleterious to aquatic life. (A) Soluble and toxic organics (B) Suspended solids (C) Heavy metals and cyanides (D) All (A), (B) & (C)
Last Answer : (D) All (A), (B) & (C)
Description : Turbidity of water is an indication of the presence of (A) Suspended inorganic matter (B) Dissolved solids (C) Floating solids (D) Dissolved gases
Last Answer : (A) Suspended inorganic matter
Description : Which of the following is the most lethal water pollutant? (A) Phenol and cyanide (B) Chlorine (C) Alkalis (D) Suspended solids
Last Answer : (A) Phenol and cyanide
Description : Turbidity of raw water is a measure of (A) Suspended solids (B) Acidity of water (C) B.O.D. (D) None of these
Last Answer : (A) Suspended solids
Last Answer : Remove suspended solids
Description : In domestic sewage, suspended solids, colloidal and dissolved materials constitute
Last Answer : In domestic sewage, suspended solids, colloidal and dissolved materials constitute A. 0.1 B. 0.056 C. 0.027 D. 0.001
Description : The function of skimming tank in sewage treatment is to remove – (1) oil and fatty substances (2) suspended solids (3) gritty substances (4) inorganic substances
Last Answer : (1) oil and fatty substances Explanation: Oil and grease traps are small size skimming basins provided to remove oil and grease and other small floating materials such as fats, vegetable debris, ... content of wastewater rise to the surface of wastewater and remains on top of liquid until removed.
Description : Tabular bowl centrifuges as compared to disk bowl centrifuges (A) Operate at higher speed (B) Employ bowl of larger diameter (C) Can’t be operated under pressure/vacuum (D) Can’t be used for separation of fine suspended solids from a liquid
Last Answer : (A) Operate at higher speed
Description : Which of the following is the most suitable filter for separation ofabrasive solids suspended in a corrosive liquid? (A) Sand bed filter (B) Plate and frame filter press (C) Vacuum filter (D) Batch basket centrifuge
Last Answer : (C) Vacuum filter
Description : A packed tower compared to a plate tower for a particular mass transfer operation (A) Incurs smaller pressure drop (B) Allows installation of cooling coils (C) Is less costly when built in large sizes/diameters (D) Is more suitable, if suspended solids are present in fluid stream
Last Answer : (A) Incurs smaller pressure drop
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 : Which of the following in sewage treatment removes suspended solids? (a) Secondary treatment (b) Primary treatment (c) Sludge treatment (d) Tertiary treatment
Last Answer : (b) Primary treatment
Description : During sewage treatment, effluent from which one of the following treatment units has minimum wt/vol amount of suspended solids? (a) Detritus channel (b) Primary sedimentation tank (c) Secondary sedimentation tank (d) Activated sludge process aeration tank
Last Answer : (d) Activated sludge process aeration tank
Description : Which of the following in sewage treatment removes suspended solids ? (1) Secondary treatment (2) Primary treatment (3) Sludge treatment (4) Tertiary treatment
Last Answer : (2) Primary treatment
Description : The function of skimming tank in sewage treatment is to remove (1) oil and fatty substances (2) suspended solids (3) gritty substances (4) inorganic substances
Last Answer : oil and fatty substances
Description : Disinfection of drinking water, is done to remove (A) Odour (B) Bacterias (C) Turbidity (D) Colour
Last Answer : (B) Bacterias
Description : Disinfection of drinking water is done to remove (A) Turbidity (B) Odour (C) Colour (D) Bacterias
Last Answer : (D) Bacterias
Description : Aeration of water is done to remove (A) Odour (B) Colour (C) Bacterias (D) Turbidity
Last Answer : (A) Odour
Description : Standard process of chlorination of water, is done by (A) Plain chlorination (B) Pre-chlorination (C) Post-chlorination (D) Double chlorination
Last Answer : (C) Post-chlorination
Description : During treatment of water, sedimentation is done (A) Before filtration (B) After filtration (C) Simultaneously with filtration (D) Along with chlorination
Last Answer : (A) Before filtration
Description : Most widely and commonly used coagulant for the removal of suspended impurities in water is (A) Bleaching powder (B) Slaked lime (C) Alum (D) Copper sulphate
Last Answer : (C) Alum
Description : Chlorination of benzene is done to produce benzene hexachloride (a pesticide) in a photochemical reactor lined with (A) Karbate (B) Lead or glass (C) Fireclay bricks (D) PVC
Last Answer : (B) Lead or glass