In fermentation of dough which is the main gas produced?

1

(a)

Carbon dioxide

(b)

Hydrogen

(c)

Both (a) and (b)

(d)

Methane

What would happen if oxygen availability to activated sludge flocs is reduced?

1

(a)

It will slow down the rate of degradation of organic matter

(b)

The centre of flocs will become anoxic, which would cause death

(c)

Flocs would increase in size as anaerobic bacteria would grow around flocs

(d)

Protozoa would grow in large numbers

Mycorrhiza does not help the host plant in:

1

(a)

Enhancing its phosphorus uptake capacity

(b)

Increasing its tolerance to drought

(c)

Enhancing its resistance to root pathogens

(d)

Increasing its resistance to insects

Methanogens do not produce

1

(a)

oxygen

(b)

methane

(c)

hydrogen sulfide

(d)

carbon dioxide

Activated sludge should have the ability to settle quickly so that it can

1

(a)

be rapidly pumped back from sedimentation to aeration tank

(b)

absorb pathogenic bacteria present in waste water while sinking to the bottom of the settling tank

(c)

be discarded and anaerobically digested

(d)

absorb colloidal organic matter

Which one is the most important role of microorganism of the well being of humans?

1

(a)

sewage treatment

(b)

production of methane

(c)

production of SO₂

(d)

conversion of milk to curd

The primary treatment of waste water involves the removal of

1

(a)

dissolved impurities

(b)

stable particles

(c)

toxic substances

(d)

harmful bacteria.

BOD of waste water is estimated by ,measuring the amount of

1

(a)

total organic matter

(b)

biodegradable organic matter

(c)

oxygen evolution

(d)

oxygen consumption.

The vitamin whose content increases following the conversion of milk into curd by lactic acid bacteria

1

(a)

vitamin C

(b)

vitamin D

(c)

vitamin B₁₂

(d)

vitamin E.

Which one of the following alcoholic drinks is produced without distillation?

1

(a)

Wine

(b)

Whisky

(c)

Rum

(d)

vitamin E.