Water supply

Question 1

What are the primary applications of water in industrial use?

Answer 1

Heat transfer, steam production, raw material incorporation, sanitation, and miscellaneous uses such as mining and nuclear shielding.

Question 2

What percentage of total water use globally is attributed to industrial use?

Answer 2

22%.

Question 3

Which types of industries are the largest consumers of industrial water?

Answer 3

Food, paper, chemical, refined petroleum, and primary metals industries.

Question 4

How does industrial water use differ in high-income vs. low-income countries?

Answer 4

High-income countries use 59%, while low-income countries use only 8% of their water for industrial purposes.

Question 5

What are the three main sources of water for industrial use?

Answer 5

Groundwater, surface water, and piped water.

Question 6

What is groundwater, and how is it replenished (fill up)?

Answer 6

Groundwater is found in saturated zones of sand, gravel, and porous rock. It is replenished (fill up) by surface water from precipitation, streams, and rivers.

Question 7

What are examples of surface water sources?

Answer 7

Rivers, lakes (freshwater), seas, and oceans (saltwater).

Question 8

What factors affect water quality in industrial use?

Answer 8

Temperature, suspended solids, bacterial count, color, odor, dissolved impurities, hardness, and alkalinity.

Question 9

What are the main methods of water treatment in industries?

Answer 9

Disinfection, coagulation, sedimentation, filtration, water softening, and ion exchange.

Question 10

Why is disinfection crucial in water treatment, and what is a common disinfectant?

Answer 10

Disinfection is essential for eliminating bacteria. Chlorine or hypochlorites are commonly used.

Question 11

What is the purpose of coagulation in water treatment?

Answer 11

To aggregate non-settleable solids using coagulants like aluminum sulfate and ferric sulfate.

Question 12

What is ion exchange, and what is its primary industrial use?

Answer 12

Ion exchange involves reversible ion replacement between a liquid and solid without altering the solid’s structure. It is used for water softening to achieve zero hardness.

Question 13

What is the largest demand for water in manufacturing?

Answer 13

Heat transfer

Question 14

Why is condensate reuse significant in steam production?

Answer 14

Reusing condensate reduces the amount of water needed.

Question 15

How is water used as a raw material in industries?

Answer 15

As a reactant (e.g., in acetylene production), a solvent (for washing), or directly incorporated into products (e.g., beverages).

Question 16

What industries commonly use water for miscellaneous purposes?

Answer 16

Mining, pulp and paper, sugar, and for effluent dilution or as a source of kinetic energy.

Question 17

What are the four main problems associated with industrial water use?

Answer 17

Corrosion, deposits, biological growth, and pollution.

Question 18

What factors affect the rate of corrosion in industrial systems?

Answer 18

Oxygen content, temperature, velocity, dissolved solids, hydrogen ion concentration, and bacteria.

Question 19

What are the main causes of deposits in industrial systems?

Answer 19

Corrosion, precipitation of solids, and bacterial growth.

Question 20

What are the classes of deposits found in industrial systems?

Answer 20

Sludge, scale, biological deposits, and corrosion products.

Question 21

What is biological growth, and how does it affect industrial systems?

Answer 21

Growth of organisms like algae, fungi, and bacteria; it reduces heat exchange efficiency, contributes to corrosion, and causes odor or color issues.

Question 22

What are the common methods for preventing corrosion?

Answer 22

Using protective molecular films (e.g., chromates, silicates) to prevent oxygen from contact with metal surface
Controlling CaCO₃ deposition by addition of lime
Cathodic protection usually used to protect steel, water pipelines etc.

Question 23

How is biological growth prevented in industrial systems?

Answer 23

By adding chlorine, chromates, or other agents like algaecides and fungicides.

Question 24

What are the main pollutants found in industrial water effluent?

Answer 24

Insecticides, herbicides, detergents, and factory discharge.

Question 25

What are the types of detergents mentioned, and which are slow to biodegrade?

Answer 25

ABS (branched-chain alkyl benzene sulfonates), LAS (linear alkyl benzene sulfonates), and nonionic surfactants like nonyl phenoxy ethoxylate. ABS and LAS degrade slowly.