In the secondary treatment or biological treatment of sewage water, the primary effluent is passed into large aeration tanks where it is constantly agitated mechanically and the air is pumped into it. This allows:
1. vigorous growth of useful aerobic microbes into flocs
2. the decrease in the number of aerobes in the water
3. rapid increase in the count of methanogens
4. a dramatic decrease in the anaerobic methanogens

Subtopic:  Microbes in Sewage Treatment |
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Consider the two statements:

I:  Indirectly, BOD is a measure of the organic matter present in the water.
II:  The greater the BOD of wastewater, the more its polluting potential.

1. Both I and II are correct
2. Only I is correct
3. Only II is correct
4. Both I and II are incorrect

Subtopic:  Microbes in Sewage Treatment |
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What is true regarding the activated sludge generated during the secondary treatment of sewage water?

I:  It is made up of aerobic bacteria that sediment down
II:  A large part of the activated sludge is pumped back into the aeration tank to serve as the inoculum.
III:  A minor part of the sludge is pumped into large tanks called anaerobic sludge digesters.

1. Only I 2. Only II and III
3. Only I and III 4. I, II and III

Subtopic:  Microbes in Sewage Treatment |
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The part of the complex stomach of ruminants that has methanogens present is the:

1. Omassum 2. Abomasum
3. Rumen 4. Reticulum
Subtopic:  Microbes in Production of Biogas |
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The major problem with the use of chemicals to control plant diseases and pests is:
1. High cost
2. Ineffectivity against most pathogens
3. Difficulty in production
4. Non-specific nature

Subtopic:  Microbes in Production of Biogas | Microbes in Biocontrol Agent |
 64%
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What is incorrect regarding organic farming?

1.  It relies on controlling pests by natural predation rather than introduced chemicals.
2.  A key belief of the organic farmer is that biodiversity furthers health.
3.  Pests are totally eradicated.
4.  Reduces dependence on toxic chemicals and pesticides.

Subtopic:  Microbes in Biocontrol Agent |
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Match each item in Column I [Bio-control agent] with the pest/pathogen in Column II and select the correct answer from the codes given below:

 

COLUMN I

 

COLUMN II

A.

Ladybird

a.

Aphids

B.

Dragonflies

b.

Mosquitoes

C.

Bacillus thuringiensis

c.

Butterfly caterpillars

D.

Trichoderma

d.

Fungi

Codes

A B C D
1. a b c d
2. b a c d
3. a b d c
4. b a d c

Subtopic:  Microbes in Biocontrol Agent |
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Baculoviruses are:
1. Species specific; Broad spectrum insecticides
2. Generalized; Broad spectrum insecticides
3. Species specific; Narrow spectrum insecticides
4. Generalized; Narrow spectrum insecticides

Subtopic:  Microbes in Biocontrol Agent |
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Match each item in Column I [Diazotroph] with the feature in Column II and select the correct answer from the codes given below:

 

Column I

 

Column II

A.

Cyanobacteria

a.

Actinorhizal symbiont

B.

Frankia

b.

Do not form nodules

C.

Rhizobium

c.

Free-living nitrogen fixer

D.

Azotobacter

d.

Legume symbiont

Codes

A B C D
1. a b c d
2. b a c d
3. a b d c
4. b a d c
Subtopic:  Microbes as Biofertilizer |
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Arbuscular mycorrhizas are formed only by fungi in the division:

1. Ascomycota 2. Glomeromycota
3. Basidiomycota 4. Microsporidia
Subtopic:  Microbes as Biofertilizer |
 56%

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