MCQs on Sewage Treatment 1.
1. Question
1 points
The rate of accumulation of sludge in septic tanks is recommended as
2.
o
1.
30 litres/person/year
o
2.
25 litres/person/year
o
3.
30 litres/person/month
o
4.
25 litres/person/month.
2. Question
1 points
For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed
3.
o
1.
10 ppm.
o
2.
3 PPm
o
3.
4 PPm
o
4.
5 PPm
3. Question
1 points
The dimensions of a rectangular settling tank are : length 24 m, width 6 m and an d depth 3 m. If 2 hour detention period for tanks is recommended, the rate of flow of sewage per hour, is
4.
o
1.
204 cu m
o
2.
212 cu m
o
3.
208 cu m
o
4.
216 cu m
4. Question
1 points
When drainage to sewage ratio is 20, the peak dry weather flow is
5.
o
1.
slightly less than 5% of the design discharge
o
2.
20% of the design discharge
o
3.
none of these.
o
4.
slightly more than 5% of the design discharge
5. Question
1 points
An inverted siphon is designed generally for
6.
o
1.
one pipe
o
2.
two pipes
o
3.
three pipes
o
4.
four pipes.
6. Question
1 points
A rainfall may be classified as acidic if its pH value is less or equal to
7.
o
1.
5
o
2.
4
o
3.
7
o
4.
6
7. Question
1 points
Self-cleansing velocity is
8.
o
1.
velocity of water at flushing
o
2.
velocity at which no accumulation remains in the drains
o
3.
velocity at dry weather flow
o
4.
velocity of water in a pressure filter.
8. Question
1 points
The non-clog pump which permits solid matter to pass out with the liquid sewage, is
9.
o
1.
pneumatic ejector
o
2.
centrifugal pump
o
3.
reciprocating pump
o
4.
none of these.
9. Question
1 points
The minimum recommended diameter of sewers, is o
1.
15cm
o
2.
10cm
o
3.
20cm
o
4.
5cm
10. 10. Question
1 points
Aerobic bacterias o
1.
consume organic matter as their food
o
2.
flourish in the presence of free oxygen
o
3.
oxidise organic matter in sewage
o
4.
all
11. 11. Question
1 points
The width of a rectangular sewer is twice its depth while discharging 1.5 m/sec. The width of the sewer is o
1.
0.88 m
o
2.
0.68 m
o
3.
1.36 m
o
4.
1.76 m.
12. 12. Question
1 points
If the over land flow from the critical point to the drain is 8 km and the difference in level is 12.4 m, the inlet time is o
1.
3 hours
o
2.
2 hours
o
3.
4 hours
o
4.
5 hours.
13. 13. Question
1 points
In a fully mechanised composting plant, involves o
1.
mechanized segregation
o
2.
mechanized receipt
o
3.
all of these.
o
4.
mechanized pulverising of refuse
14. 14. Question
1 points
The screens are fixed o
1.
parallel to the direction of flow
o
2.
perpendicular to the direction of flow
o
3.
none of these.
o
4.
at an angle 30° to 60° to the direction of flow
15. 15. Question
1 points
If D is the diameter of upper circular portion, the overall depth of a standard egg shaped section, is
o
1.
1.25 D
o
2.
1.5 D
o
3.
D
o
4.
1.75 D
16. 16. Question
1 points
Pick up the correct statement from the following : o
1.
The solubility of oxygen in sewage is 95% that is in distilled water
o
2.
All
o
3.
In treated sewage, 4 PPm of D.O. is essential
o
4.
Only very fresh sewage contains some dissolved oxygen
17. 17. Question
1 points
For treating the sewage of a large city, you will recommend o
1.
sedimentation tanks with high rate trickling filters
o
2.
a plant consisting of Imhoff tanks with low rate trickling filters
o
3.
a sedimentation tank and an activated sludge treatment plant
o
4.
none of these
18. 18. Question
1 points
If the diameter of sewer is 225 mm, the gradient required for generating self cleansing velocity, is o
1.
1 in 120
o
2.
1 in 60
o
3.
1 in 100
o
4.
none of these.
19. 19. Question
1 points
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 o
1.
200 ppm
o
2.
225 ppm
o
3.
None of these.
o
4.
250 ppm
20. 20. Question
1 points
In olden days the type of section adopted in trunk and out fall sewers was o
1.
horse shoe shaped
o
2.
parabolic shaped
o
3.
egg shaped
o
4.
circular shaped.
The correct answer for each question is indicated by a
1 INCORRECT
.
Which of the following microorganisms is part of the Environmental Protection Agency's microbial water contaminant candidate list for their ability to cause severe health problems? A) B) C) D)
Calciviruses Escherichia coli O157:H7 Vibrio cholerae
All of the above
2 CORRECT In water treatment procedures, the purpose of coagulation and flocculation is t o A)
Disinfect the water supply
B) C) D)
3 INCORRECT
Remove microorganisms, organic matter, and suspended fine particles Soften the water by removing calcium and magnesium Remove taste and odor problems
In the water purification process, chlorination may create disinfection byproducts (DBPs) that may be _________________. A) B) C) D)
Allergens Neurotoxins Carcinogens All of the above
4 CORRECT A major source of Giardia and Cryptosporidium contamination in the water supply comes from A) B) C) D)
5 INCORRECT
Canada geese Rodents Sewage
According to the Total Coliform Rule, the maximum containment l evel goal (MCLG) for total and fecal coliforms is set at A) B) C) D)
6 INCORRECT
Cattle farms
0 100 cells/ml 1000 cells/ml 10,000 cells/ml
Which of the foll owing is true of indicator organisms, or microbes that can serve as an index of possible water contamination by human pathogens? A)
It should be harmless to humans
B) C) D)
7 INCORRECT
B) C) D)
B) C) D)
Coliforms Rhizobia Cyanobacteria Staphylococci
Most probable number (MPN) Biochemical oxygen demand (BOD) Membrane filter technique Defined substrate test
Which of the following tests can be used to test for both coliforms and E. coli ?
A) B) C) D)
10 INCORRECT
All of the above
The common, preferred method of evaluation of the microbiological characteristics of water is A)
9 INCORRECT
The assay procedure for the indicator should have great specificity
Which of the foll owing is a common index organism of water contamination?
A)
8 INCORRECT
It should survive longer than the hardiest enteric pathogens
Most probable number (MPN) Membrane filtration technique Presence-absence (P-A) test Colilert defined substrate test
The preferred indictor microorganism in brackish and marine waters is the
A) B)
Staphylococci Coliforms
C) D)
11 INCORRECT
B) C) D)
B) C) D)
Molecular techniques Serological methods None of the above
Total organic carbon (TOC) test Chemical oxygen demand (COD) test Biochemical oxygen demand (BOD) test All of the above
Which major step in wastewater treatment prepares the wastewater for treatment by physically removing the majority of solid material? A) B) C) D)
14 INCORRECT
Pure culture techniques
Which of the foll owing methods can be used to measure carbon removal during wastewater treatment? A)
13 INCORRECT
Cyanobacteria
Which of the foll owing techniques provides a quick, effective, and quantitative means of identifying microbial contaminants in water? A)
12 INCORRECT
Enterococci
Primary treatment Secondary treatment Tertiary treatment All of the above
Which major step in wastewater treatment promotes the biological transformation of dissolved organic matter into microbial biomass and carbon dioxide? A) B)
Primary treatment Secondary treatment
C) D)
15 CORRECT
B) C) D)
Bulking Activated Aerated Oxidized
Where is methane produced during the wastewater treatment process?
A) B) C) D)
17 INCORRECT
All of the above
In the secondary step of wastewater treatment, ________ sludge is oxidized and recycled under aerobic conditions. A)
16 INCORRECT
Tertiary treatment
Anaerobic digestion Activated sludge system Trickling filters All of the above
Which of the foll owing is true of anaerobic digestion in the wastewater treatment process? Microbes consume large amounts of organic matter because A) methanogenesis is energetically very inefficient B) C) D)
18 INCORRECT
Methane can be produced as a by-product of t he process Dried sludge can be sold as garden fertilizer All of the above
The removal of nitrogen and phosphorus, compounds that promote eutrophication, are removed during which stage of wastewater treatment? A) B) C)
Primary treatment Secondary treatment Tertiary treatment
D)
19 INCORRECT
Nitrogen is removed from the water supply through which of the following chemical reactions? A) B) C) D)
20 INCORRECT
B) C) D)
Anammox Chlorination of ammonia All of the above
Total organic carbon (TOC) test Chemical oxygen demand (COD) test Biochemical oxygen demand (BOD) test All of the above
The combination of adsorption and biological predation of microbes is used in which of the following wastewater treatment processes? A) B) C) D)
22 INCORRECT
Denitrification
Which of the following methods is used to measure the portion of total carbon oxidized by microorganisms over a 5-day period at 20 degrees Celsius? A)
21 CORRECT
All of the above
Wetland bioremediation systems Home septic tanks Municipal sewage systems All of the above
Which of the foll owing is true regarding home septic systems?
A) B) C) D)
Most types of land are able to support septic systems Minimal nitrogen and phosphorus are produced Fractured rocks may result in contamination of well water with pathogens All of the above
23 INCORRECT
Which of the foll owing is an outcome of biodegradation? Minor changes in organic molecules with little change in its chemical A) structure B) C) D)
24 CORRECT
B) C) D)
All of the above
Denitrification Dehalogenation Decarboxylation Transpeptidation
Which of the foll owing stereochemical structures is biodegraded at a much slower rate? A) B) C) D)
26 INCORRECT
Complete mineralization of organic molecules into inorganic forms
The first step in the biodegradation of many contaminants is
A)
25 INCORRECT
Reversible fragmentation of complex organic molecules
Meta Ortho Para
All of the above
The change in the characteristics of a microbial community in response to the addition of inorganic or organic substrates is called ______________. A) B) C) D)
Natural selection Directed evolution Acclimation Adaptive radiation
27 INCORRECT
Which of the foll owing methods is an emerging approach to the bioremediation of contaminants? A) B) C) D)
28 INCORRECT
B) C) D)
Industrial septic systems All of the above
Nutrient amendment Nutrient stimulation Cometabolism Carbonization
Which of these methods were used in the biodegradation of oil in Prince Willi am Sound following the Exxon-Valdez oil spill in 1989? A) B) C) D)
30 INCORRECT
Anaerobic digesters
The addition of easily metabolized organic matter to a natural microbial community with the purpose of increasing the rate of biodegradation is called A)
29 INCORRECT
Microbial fuel cells
Addition of nitrogen and phosphorus to promote degradation Adjustment of the natural microbial community's composition Addition of bacterial predators and phages All of the above
In ___________________, microorganisms t hat produce acids are used to solubilize desirable metals. A) B) C) D)
Bioremediation Biodegradation Bioleaching Bioacidification
31 INCORRECT
The addition of known active microbes to soil or water with the purpose of accelerating microbial processes is called A) B) C) D)
Biodegradation Bioremediation Bioaccentuation Bioaugmentation
