Here are 1000 Waste Water Engineering MCQ (Chapterwise).
1. What is Waste Water Engineering?
a) use of engineering approaches to enhance the cleanliness of human populations
b) removing and disposing of human waste
c) providing safe drinking water
d) all of the mentioned
View Answer
Explanation: Sanitary engineering, often known as public health engineering or waste water engineering, is the use of engineering approaches to enhance the cleanliness of human populations, typically by removing and disposing of human waste and providing safe drinking water.
2. How is Chemical Oxygen Demand (COD) calculated?
a) Waste water is oxidised chemically using strontium in acid solutions
b) Waste water is oxidised chemically using bromine in acid solutions
c) Waste water is oxidised chemically using dichromate in acid solutions
d) Waste water is oxidised chemically using sodium in acid solutions
View Answer
Explanation: Waste water is oxidised chemically using dichromate in acid solutions. High COD value indicates that the presence of inorganic compounds is high. Inorganic compounds get chemically oxidised and this results in the increase of organic compounds in the sample.
3. Which of the following is the next step after water abstraction in waste water treatment?
a) Treatment
b) Supply to consumers
c) Supply to receiving body
d) Combine with stormwater
View Answer
Explanation: Initially, water is abstracted from the river, lake or water table and has a certain quality. Hence water is sent for treatment, where it undergoes transformation to be able to comply with intended uses.
4. Which of the following type of treatment methods are used for municipal and industrial waste waters?
a) Main stream
b) Slow rate
c) Overflow
d) Rapid infiltration
View Answer
Explanation: Slow Rate (SR) systems are the predominant form of land treatment for municipal and industrial waste-water. Such a technology incorporates waste-water treatment, water reuse, crop utilization of nutrients and waste-water disposal.
5. What is the minimum diameter of pipes used for drainage of waste water?
a) 105 mm
b) 50 mm
c) 100 mm
d) 75 mm
View Answer
Explanation: Waste water is from showers, basins, kitchen sinks, washing machines and the like. This is also called grey water. Normally a minimum of 75 mm diameter pipes is used for drainage of waste water.
6. Which of the following type of waste water treatment process is used for treating waste water or industrial waste water using aeration and biological flocs?
a) Biological aeration
b) Anaerobic digestion
c) Active sludge process
d) Aeration
View Answer
Explanation: One of the sewer waste water treatment processes is a biological treatment known as activated-sludge process. Waste water is agitated and aerated to remove solids and oxidation methods are introduced to activate decomposition.
7. Which of the following is called as the waste water from different sources like bathrooms, kitchens, and washbasins?
a) Discharge
b) Sullage
c) Garbage
d) Sewage
View Answer
Explanation: Dry wastes such as dry leaves, paper and grass are called garbage. Discharge is the outflow of water or waste water. Sewage is the waste water from various houses. Sullage is the waste water from bathroom, kitchen, wash basins, etc.
8. What is the waste water flow in a sewer system during the periods of dry weather with minimum infiltration called?
a) Wet flow
b) Dry flow
c) Dry weather flow
d) Wet weather flow
View Answer
Explanation: Summers are usually dry. Hence the rainfall is minimum and is called as dry weather flow in sewers. During the rainy season or periods of high rainfall or storm, the sewers will be full and are called wet weather flow.
9. What percentage of solids does waste water contain?
a) 0.1%
b) 1%
c) 0.5%
d) 5%
View Answer
Explanation: Waste water contains 99.9% water and 0.1% solids. The goal is to remove this 0.1% of solids. Waste water is the water generated by industries and communities.
10. When alum is added to the waste water containing calcium ions which compound is formed as a precipitate?
a) Al2 (SO4)3
b) CaCO3
c) Al(OH)3
d) Ca(OH)2
View Answer
Explanation: When alum is added to a waste water containing calcium salts Al (OH)3 is precipitated. This sis a gelatinous floc. This reaction sweeps out suspended particles.
11. What is the lowest waste water flow in hospitals?
a) 40 lpcd
b) 900 lpcd
c) 700 lpcd
d) 50 gpcd
View Answer
Explanation: The unit lpcd stands for litres per capita per day and gpcd stands for gallons per capita per day. 40 lpcd indicates the minimum water usage for places like kids play home and schools. 700 lpcd is for hospitals.
12. How many forms of nitrogen are present in waste water?
a) 5
b) 4
c) 3
d) 2
View Answer
Explanation: There are different types of nitrogen present in waste water. Basically, our types of nitrogen are present. They are organic nitrogen, ammonia nitrogen, nitrate nitrogen and nitrite nitrogen.
13. Which of the following water carriage system is used in urban cities like Bangalore?
a) Partially separate system
b) Partially combined system
c) Combined system
d) Separate system
View Answer
Explanation: Urban cities have a large area and high population, therefore water usage is more and sewage generated will also be more. Hence, a separate system to carry sewage and stormwater is necessary. Whereas in rural areas, precipitation will be absorbed by the ground and infiltered. Therefore only a little amount of precipitation forms storm. Hence the combined system is preferred.
14. Assume in a sample of waste water around 60% TSS is removed by primary sedimentation without chemical addition. Calculate the mass of TSS removed for the following data.
Amount of TSS present initially: 220 mg/L
Waste water flow: 1000 m3/d
a) 132 kg/d
b) 100 kg/d
c) 102 kg/d
d) 130 kg/d
View Answer
Explanation: The amount of TSS removed is 132 kg/d. The mass of the TSS removed = 220kg/1000/m3 x 0.6×1000 m3/d =132 kg/d. 220 mg/L is converted into Kg/L.
15. Which of the following is the controlled application of waste water onto the land surface to achieve a specified level of treatment?
a) Soil treatment
b) Land treatment
c) Waste water treatment
d) Water treatment
View Answer
Explanation: The controlled application of waste water onto the land surface to achieve a specified level of treatment through natural physical, chemical, and biological processes within the plant soil-water matrix is called land treatment.
16. Advanced waste water sludge constitutes which of the following?
a) Chemical and biological solids
b) Biological solids
c) Settlable solids
d) Chemical sludge
View Answer
Explanation: The advanced waste water sludge constitutes biological sludge. This also constitutes chemical sludge. The advanced waste water sludge is sent to the primary clarifier, where mixing is carried out in order to provide an uniformity to the mixture.
17. What is the maximum concentration of total solids present in waste water?
a) 850 mg/L
b) 1200 mg/ L
c) 720 mg/L
d) 350 mg/L
View Answer
Explanation: The concentration of total solids present in weak waste water is 350 mg/ L. The concentration of total solids present in strong waste water is 1200 mg/ L. The medium range consists of 720 mg/ L.
18. Which of the following tends to resist conventional methods of waste water treatment?
a) Refractory organics
b) Priority pollutants
c) Suspended solids
d) Nutrients
View Answer
Explanation: Refractory organics tend to resist conventional methods of waste water treatment. Typical examples include surfactants, phenols, and agricultural pesticides.
19. Which of the following waste water constituents are removed by chemical immobilization?
a) Suspended solids
b) Metals
c) Phosphorus
d) BOD
View Answer
Explanation: Chemical immobilization is a process consisting of precipitation and adsorption. Phosphorus is removed by chemical immobilization and it is also removed by plant uptake. The plant utilizes phosphorus for various purposes.
20. Which of the following represents the heavier inert matter in waste water?
a) Screens
b) Grit
c) Debris
d) Waste
View Answer
Explanation: Grit represents the heavier inert matter in waste water which will not decompose in treatment processes. It is identified with matter having a specific gravity of about 2.65 and design of grit chambers is based on the removal of all particles of about 0.011 inches or larger (65 mesh).
21. Which of the following process is employed to gain sufficient head for the waste water?
a) Fermentation
b) Oxidation
c) Screening
d) Pumping
View Answer
Explanation: Pumping facilities may be employed to gain sufficient head for the waste water to flow through the treatment works to the point of final disposal. Pumping is also generally required for recirculation of all or part of the flow around certain units within the plant. Pumping facilities are classified as influent, effluent, or recirculation stations and perform a critical function.
22. Which of the following is the most commonly used coagulant?
a) Ferric sulphate
b) Coal
c) Alum
d) Limestone
View Answer
Explanation: Sedimentation using chemical coagulation has been implied mainly to pre-treatment of industrial or process waste waters and removal of phosphorus from domestic waste waters. Alum is mostly used as it is cheap and easily available.
23. Which of the following waste water treatment plant may or may not need the screens?
a) Industrial
b) Sewage
c) Chemical
d) Domestic
View Answer
Explanation: Industrial waste water treatment plants may or may not need the screens. Screens must be provided even for industrial waste water treatment plants to separate labels, stopper, cardboard, and other packing materials.
24. Which of the following is the product obtained when a coagulant is mixed with waste water?
a) Floc
b) Grit
c) Acid
d) Sediments
View Answer
Explanation: The most commonly used coagulant is alum. A coagulant combines with the impurities in waste water and forms an end product called flocs which is greater in diameter and can be easily removed.
25. What is the waste water called after physical and biological removal of solids?
a) Secondary treated water
b) Secondary treated waste water
c) Primary effluent
d) Primary treated water
View Answer
Explanation: After this kind of treatment that is after physical removal of solids and biological removal of solids, the waste water may be called secondary-treated waste water.
26. What is the amount of phosphorus present in municipal waste water?
a) 5-20 mg/L
b) 4-12 mg/L
c) 2-8 mg/L
d) 1-2 mg/L
View Answer
Explanation: Municipal waste waters may contain from 5 to 20 mg/l of total phosphorous, of which 1-5 mg/l is organic and the rest in inorganic. The individual contribution tends to increase because phosphorous is one of the main constituents of synthetic detergents.
27. How does the waste water enter the reactor?
a) Top and side
b) Side
c) Bottom
d) Top
View Answer
Explanation: Waste water enters the reactor from the bottom and flows forward. A suspended sludge blanket filters and treats the waste water as the waste water flows through it.
28. Which of the following is the common indicator organism used in the evaluation of waste water?
a) Total coliform
b) Fecal coliform
c) Algae
d) E. coli
View Answer
Explanation: The most common indicator organism for waste water evaluation is fecal coliform but there has been discussion regarding the use of Escherichia coli (E. coli) or Total Coliform.
29. What is the minimum percentage of solids in waste water?
a) 60 %
b) 50 %
c) 30 %
d) 40 %
View Answer
Explanation: The organic matter consists mainly of proteins, carbohydrates and fats. Between 40 and 65 % of the solids in an average waste water are suspended. Usually, about 60 % of the suspended solids in a municipal waste water are 2 settleable (Ron & George, 1998).
30. What is the colour of septic waste water?
a) Light brown
b) Dark brown
c) Black
d) Grey
View Answer
Explanation: The colour of the septic water is black. If the waste water undergoes some degree of decomposition the colour of water is light grey.
31. Which of the following is constructed outside the building to carry waste water discharge?
a) S. trap
b) Gully trap
c) Floor trap
d) P. trap
View Answer
Explanation: Gully traps are constructed outside the building to carry waste water discharge from washbasin, sinks, bathroom etc.
32. What is the waste water from kitchen sinks called?
a) Brown water
b) Yellow water
c) Black water
d) Grey water
View Answer
Explanation: Normally a minimum of 75 mm diameter pipes are used for drainage of waste water. Waste water is from showers, basins, kitchen sinks, washing machines and the like. This is also called grey water.
33. Which of the following waste water does not contain sewage?
a) Sewerage
b) Grey water
c) Sullage
d) Sewage
View Answer
Explanation: The waste water coming from bathrooms and kitchens which does not contain fecal matter is known as sullage. Sewer is a pipe carrying sewage from water conduits.
34. What is the term used for the reuse of sewage sludge?
a) Biosolids
b) Potential solids
c) Manure
d) Solids
View Answer
Explanation: “Biosolids” is a term often used in waste water engineering publications and public relations efforts by local water authorities when they want to put the focus on reuse of sewage sludge after the sludge has undergone suitable treatment processes.
35. Which of the following is required to transport storm water runoff from roofs, parking lots, streets, and highways to a point of discharge?
a) Waste water sewers
b) Water sewers
c) Storm sewers
d) Sanitary sewers
View Answer
Explanation: There are different types of sewers used based on a type of flow it is designed to carry. Storm sewers are required to transport storm water runoff from roofs, parking lots, streets, and highways to a point of discharge. Storm drainage system helps to minimize flooding and soil erosion.
36. What is the upflow velocity considered for an UASB while treating domestic waste water?
a) 1-2 m/h
b) 0.8-1 m/h
c) 3-4 m/h
d) 2-3 m/h
View Answer
Explanation: The upflow velocity considered for an UASB while treating domestic waste water is 0.8-1. In most cases it is 0.9. This waste water is mixed with the influent biomass from the bottom of the reactor.
37. What is the hydraulic loading rate in m2/m3/h of a cloth disc filter assumed while designing it?
a) 2-4
b) 1-2
c) 10-20
d) 0.1-0.27
View Answer
Explanation: The hydraulic loading rate of a cloth disc filter assumed while designing it is 0.1-0. 27 m2/m3/h. This is measured in. This depends on the suspended solids present in the waste water.
38. What is the hydraulic loading rate in m2/m3/h of a disc filter assumed while designing it?
a) 2.5-8.3
b) 0.02-0.083
c) 8.3-10
d) 0.25-0.83
View Answer
Explanation: The hydraulic loading rate of a disc filter assumed while designing it is 0.25-0.83 m2/m3/h. This is measured in the units m2/m3/h. This depends on the suspended solids present in the waste water.
39. What is the function of two tanks provided in septic tank systems?
a) Store large amount of effluent
b) Divide black and grey water
c) Divide waste water and water
d) Divide solids and liquid
View Answer
Explanation: Septic systems are commonly used to treat waste water. There might be one tank that combines all black and grey water or two tanks that divide the black and grey water.
Chapterwise Multiple Choice Questions on Waste Water Engineering
- Wastewater Flow Rates, Collection and Conveyance of Sewage
- Hydraulic Design & Construction of Sewers
- Sewer Appurtenances & Sewage Pumping
- Valves, Blowers & Wastewater Characteristics
- Natural Methods of Wastewater Disposal, Chemical Reaction Engineering and Waste Water Treatment
- Unit Operations for Wastewater Treatment
- Preliminary Treatment
- Types of Settling Tank
- Sewage Filtration
- Activated Sludge Process
- BOD Removal Methods & Miscellaneous Methods
- Treatment and Disposal of Sludge
- Septic Tanks, Oil and Grease Removal
- Advanced Wastewater Treatment
- House Drainage
- Rural Sanitation
- Corrosion control & Instrumentation
1. MCQ on Wastewater Flow Rates, Collection and Conveyance of Sewage
The section contains Waste Water Engineering multiple choice questions and answers on waste systems and sewage disposal, water carriage system classification, dry weather flow and sewage rate variations.
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2. Waste Water Engineering MCQ on Hydraulic Design & Construction of Sewers
The section contains Waste Water Engineering questions and answers on minimum and maximum velocity of flow, sewer sections, construction and planning of sewer system.
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3. Waste Water Engineering MCQ on Sewer Appurtenances & Sewage Pumping
The section contains Waste Water Engineering MCQs on sewer appurtenances, pumps and pumping stations.
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4. Multiple Choice Questions on Valves, Blowers & Wastewater Characteristics
The section contains Waste Water Engineering multiple choice questions and answers on valves different types, autoclaves, blowers, wastewater characteristics and chemical characteristics determination.
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5. MCQ on Natural Methods of Wastewater Disposal, Chemical Reaction Engineering and Waste Water Treatment
The section contains Waste Water Engineering questions and answers on chemical reactions associated with water treatment, mass transfer correlation, natural streams self purification, land treatment disposal, dilution and oxygen sag analysis.
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6. MCQ on Unit Operations for Wastewater Treatment
The section contains Waste Water Engineering MCQs on unit operations and processes, reactors types in water treatment, wastewater treatment methods, sludge processing and disposal methods.
7. Waste Water Engineering MCQ on Preliminary Treatment
The section contains Waste Water Engineering multiple choice questions and answers on aerated grit chambers, screens and comminutors.
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8. Waste Water Engineering MCQ on Types of Settling Tank
The section contains Waste Water Engineering questions and answers on discrete particles settling, settling tank types, sedimentation tanks, chemical clarification and flocculant settling.
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9. Waste Water Engineering MCQ on Sewage Filtration
The section contains Waste Water Engineering MCQs on sewage filters, sand and trickling filters, high rate filtration, secondary carifiers and tube settlers.
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10. Waste Water Engineering MCQ on Activated Sludge Process
The section contains Waste Water Engineering multiple choice questions and answers on activated sludge process, diffused and mechanical aeration systems, sludge production and process control, activated sludge treatment systems and secondary settling.
11. Waste Water Engineering MCQ on BOD Removal Methods & Miscellaneous Methods
The section contains Waste Water Engineering questions and answers on oxidation ditch, aerobic and facultative ponds, bod removal methods, sequential batch reactor, moving bed reactor and bioreactor.
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12. Waste Water Engineering MCQ on Treatment and Disposal of Sludge
The section contains Waste Water Engineering MCQs on sludge treatment process, anaerobic digestion, sludge characteristics, thickening and concentration.
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13. Waste Water Engineering MCQ on Septic Tanks, Oil and Grease Removal
The section contains Waste Water Engineering multiple choice questions and answers on septic tanks, septic tanks effluent disposal, oil and grease removal methods, lamella clarifiers, suspended solids removal, oil removal belt and air flotation dissolved.
14. MCQ on Advanced Wastewater Treatment
The section contains Waste Water Engineering questions and answers on ultrafiltration, rapid and disc filtration, adsorption by activated carbon, phosphorous and nitrogen removal, biological nitrification and denitrification, wet air oxidation, uasb reactor, reverse osmosis design and membrane properties, ion exchange process, design and media properties, softners, iron, manganese and arsenic removal, disinfection process, chlorinators, ozonators and industrial wastewater characteristics.
15. Waste Water Engineering MCQ on House Drainage
The section contains Waste Water Engineering MCQs on house drainage principles and plans, pipes, traps, sanitary fittings, hydrogen sulphide in sewers, storm water flow and plumbing systems.
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16. Waste Water Engineering MCQ on Rural Sanitation
The section contains Waste Water Engineering multiple choice questions and answers on rural sanitation, dr refuse collection and disposal, excretal wastes disposal and eco friendly toilets.
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17. Waste Water Engineering MCQ on Corrosion control & Instrumentation
The section contains Waste Water Engineering questions and answers on water conduits corrosion control and water treatment plant instrumentation.
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Wish you the best in your endeavor to learn and master Waste Water Engineering!
