All Courses

Home

Biology

Microbes in human welfare

Read the following passage and answer the questions We know that large quantities of waste water are generated everyday in cities and towns. A major c

Reading Comprehension

Read the following passage and answer the questions
We know that large quantities of waste water are generated everyday in cities and towns. A major component of this waste water is human excreta. This municipal waste-water is also called sewage. It contains large amounts of organic matter and microbes. Before disposal, sewage is treated in sewage treatment plants (STPs) to make it less polluting. Treatment of waste water is done by the heterotrophic microbes naturally present in the sewage.

1) Question

The primary treatment of sewage involves which of the following step?

Distillation

Evaporation

Filtration

Condensation

Solution

Correct option is C

Primary treatment steps basically involve physical removal of particles – large and small – from the sewage through filtration and sedimentation.

2) Question

Air is pumped into the primary effluent during sewage treatment during which stage?

Primary treatment

Secondary treatment

Biological treatment

Both (B) and (C)

Solution

Correct option is D

The primary effluent is passed into large aeration tanks where it is constantly agitated mechanically and air is pumped into it.

3) Question

The greater the BOD of waste water ______________ is its polluting potential.

Less

Intermediate

No effect

Solution

Correct option is B

BOD refers to the amount of the oxygen that would be consumed if all the organic matter in one liter of water were oxidised by bacteria. The sewage water is treated till the BOD is reduced. The BOD test measures the rate of uptake of oxygen by micro-organisms in a sample of water and thus, indirectly, BOD is a measure of the organic matter present in the water. The greater the BOD of waste water, more is its polluting potential.

4) Question

During this digestion, bacteria produce a mixture of gases which include.

Methane

Carbon dioxide

Hydrogen sulphide

All of the above

Solution

Correct option is D

During this digestion, bacteria produce a mixture of gases such as methane, hydrogen sulphide and carbon dioxide. These gases form biogas and can be used as source of energy as it is inflammable.

5) Question

Biogas contains predominantly which of the following gas?

Oxygen

Methane

Nitrogen

Hydrogen

Solution

Correct option is B

Biogas is a mixture of gases (containing predominantly methane) produced by the microbial activity and which may be used as fuel.

Free Tests

Free

Must Attempt

CUET 2025 English Language Mock 01

English

50 Questions
200 Marks
45 Mins

English

Similar Questions

Column I	Column II
A. Leishmania donovani	{i}Malaria
B. Wuchereria bancrofti	{ii}Amoebiasis
C. Trypanosoma gambiense	{iii}Kala azar
D. Entamoeba histolytica	{iv}Sleeping sickness
	(v) Filariasis

Column I	Column II
A. Family	{i}Solanum
B. Kingdom	{ii}Solanaceae
C. Order	{iii}lycopersicum
D. Species	{iv}Plantae
E. Genus	(v) Solanales

Given below are two columns:
Column I lists the names of scientists and Column II lists the discoveries made by them towards understanding photosynthesis in plants.
Match the scientists with the corresponding discoveries and choose the correct code.

Column I	Column II
A. J.B. Van Helmont	{i}Starch is the first visible product of photosynthesis
B. Stephen Hales	{ii}Water of soil contributes to the growth of plants
C. Engelmann	{iii}Green plants get nourishment through their leaves from air and sunlight
D. Sachs	{iv}Action spectrum of photosynthesis