What is activated sludge? -Biology

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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

Last Answer : ANS: B

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 : Select the correct statement from the following. (a) Biogas is produced by the activity of aerobic bacteria on animal waste. (b) Methanobacterium is an aerobic bacterium found in rumen of ... sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria.

Last Answer : (d) Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria.

Description : Which of the following is put into anaerobic sludge digester for further sewage treatment? (a) Primary sludge (b) Floating debris (c) Effluents of primary treatment (d) Activated sludge

Last Answer : (d) Activated sludge

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 : Activated sludge contains large number of A.bacteria B.yeasts and molds C.protozoa D.all of these

Last Answer : D.all of these

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 : Consider the following statements : Activated sludge process can be said to comprise : 1. Conversion of dissolved organic matter into biological flocs 2. Removal of dissolved BOD of the waste water 3. Digestion of the sludge Which ... 2 and 3 (b) 1 and 2 only (c) 2 and 3 only (d) 1 and 3 only

Last Answer : (b) 1 and 2 only

Description : What: can u Calculate the dimension of the primary sludge Pump if the Concentration of total Carbon 480 mg/l and the inorganic 80 mg/l?

Last Answer : 6

Description : Sewage sludge is used as Tipping is a technique of

Last Answer : Sewage sludge is used as Tipping is a technique of A. manure B. biogas generator C. Both A and B D. Tipping

Description : What is a sludge judge and where can I find one?

Last Answer : A sludge judge helps separate oil from water. My guess is you would use it in any type of body of water that may have had an oil spill in it recently such as a well or a pond.

Description : The ‘solid waste’ is also known as - (1) Sedge (2) Toxic waste (3) Sludge (4) Scrubber

Last Answer : (3) Sludge Explanation: Solid waste, also known as sludge, refers to the residual, semi-solid material that is produced as a byproduct during sewage treatment of industrial or municipal ... results from manufacturing process such as that of factories, industries, mills, and mining operations.

Description : ______ is a by product of sewage treatment and can be decomposed to produce biogas. (1) Sewage (2) Sludge (3) Sewer (4) Scum

Last Answer : (2) Sludge Explanation: Sludge refers to the residual, semi-solid material that is produced as a byproduct during sewage treatment of industrial or municipal wastewater. It can be used to produce biogas through a process called anaerobic digestion or fermentation.

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

Last Answer : ANS: A

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 : 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

Last Answer : ANS: C

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 : The rate of accumulation of sludge per person per year, is A. 10 litres B. 15 litres C. 20 litres D. 25 litres

Last Answer : ANS: C

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

Last Answer : ANS: A

Description : In normal conditions, the period for sludge digestion, is A. 10 days B. 20 days C. 30 days D. 60 days

Last Answer : ANS: C

Description : In a sludge tank, the gas mainly produced, is A. Oxygen B. Nitrogen C. Hydrogen D. Carbon dioxide

Last Answer : ANS: D

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 %

Last Answer : ANS: B

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

Last Answer : ANS: A

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

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 : The sludge does not contain waste water from A. Bath rooms B. Wash basins C. Kitchen sinks D. Toilets

Last Answer : ANS: D

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 : 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

Last Answer : ANS: C

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

Last Answer : ANS: D

Description : Asphalts are (A) Low molecular weight & low boiling point compounds present in petroleum (B) Desirable in catalytic cracking feedstock, because they produce coke (C) Readily oxidisable and form carbonaceous sludge (D) All (A), (B) & (C)

Last Answer : (C) Readily oxidisable and form carbonaceous sludge

Description : Separation of a suspension or slurry into a supernatant clear liquid (free from particles) and a thick sludge containing a high concentration of solid is called (A) Classification (B) Sedimentation (C) Clarification (D) Decantation

Last Answer : (B) Sedimentation

Description : With increase in the pressure drop across the cake, the specific cake resistance for the compressible sludge (A) Increases (B) Decreases (C) Remains constant (D) Increases linearly

Last Answer : (A) Increases

Description : Which one of the following equipments is essentially required for growing microbes on a large scale, for industrial production of enzymes? (a) Bioreactor (b) BOD incubator (c) Sludge digester (d) Industrial oven

Last Answer : (a) Bioreactor

Description : What gases are produced in anaerobic sludge digesters? (a) Methane and CO2 only (b) Methane, Hydrogen sulphide and CO2 (c) Methane, Hydrogen sulphide and O2 (d) Hydrogen sulphide and CO2

Last Answer : (b) Methane, Hydrogen sulphide and CO2

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 : Sewage sludge is an example of the __________ fluid. (A) Bingham plastic (B) Newtonian (C) Pseudo plastic (D) Dilatent

Last Answer : (A) Bingham plastic

Description : Sewage sludge is __________ type of non-Newtonian fluid. (A) Dilatant (B) Bingham plastic (C) Pseudo plastic (D) None of these

Last Answer : (B) Bingham plastic

Description : An ideal plastic substance indicates no deformation, when stressed upto yield stress, but behaves like a Newtonian fluid beyond yield stress. Which of the following is an ideal plastic? (A) Sewage sludge (B) Rubber latex (C) Blood (D) Sugar solution

Last Answer : (A) Sewage sludge

Description : Which of the following is a Newtonian fluid? (A) Rubber latex (B) Sewage sludge (C) Quicksand (D) Non-colloidal solution

Last Answer : (D) Non-colloidal solution

Description : Which of the following is the most common pump for pumping either raw sewage or sludge? (A) Electromagnetic pump (B) Centrifugal pump (C) Reciprocating pump (D) Gear pump

Last Answer : (C) Reciprocating pump

Description : Lagooning process is mainly a means of the (A) Sludge disposal (B) Reduction of excessive flow in sewers (C) Biological treatment of wastes (D) None of these

Last Answer : (A) Sludge disposal

Description : The principal gas evolved from sludge digestion tank is (A) CO (B) CO2 (C) CH4 (D) N2

Last Answer : (C) CH4

Description : The main type of sludge gas evolved during sewage treatment in Imhoff tank is (A) CO2 (B) CH4 (C) CO (D) H2

Last Answer : (B) CH4

Description : Function of fusible plug in a boiler is to (A) Drain out water and sludge from the boiler during repair (B) Put off fire in the furnace when water level in the boiler falls to unsafe limit (C) Guard the boiler in case of abnormal rise in steam pressure (D) All (A), (B) & (C)

Last Answer : (B) Put off fire in the furnace when water level in the boiler falls to unsafe limit

Description : Blow off cock is provided in steam boiler to (A) Guard the boiler in case of abnormal rise in steam pressure (B) Drain out water and sludge during its repair (C) Regulate the supply of water in boiler (D) Put out the fire in the furnace when the water level in the boiler falls to unsafe limit

Last Answer : (B) Drain out water and sludge during its repair

Description : Which of the following is not a result of the excess of impurity in boiler-feed. a) Scale and sludge formation b) Decomposition c) Corrosion, priming and foaming d) Caustic embrittlement

Last Answer : b) Decomposition

Description : Which of the following operational problems relate to the functioning of rapid gravity filter ? 1. Inadequate media comprising filter bed 2. Sludge bulking 3. Mud balls 4. Negative head 5. Incrustation of media (a) 1, 3, 4 and 5 ... 2, 3 and 4 only (c) 2, 3, 4 and 5 only (d) 1, 2, 3, 4 and 5

Last Answer : (a) 1, 3, 4 and 5 only

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 : 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