Water supply Flashcards
What are the primary applications of water in industrial use?
Heat transfer, steam production, raw material incorporation, sanitation, and miscellaneous uses such as mining and nuclear shielding.
What percentage of total water use globally is attributed to industrial use?
22%.
Which types of industries are the largest consumers of industrial water?
Food, paper, chemical, refined petroleum, and primary metals industries.
How does industrial water use differ in high-income vs. low-income countries?
High-income countries use 59%, while low-income countries use only 8% of their water for industrial purposes.
What are the three main sources of water for industrial use?
Groundwater, surface water, and piped water.
What is groundwater, and how is it replenished (fill up)?
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.
What are examples of surface water sources?
Rivers, lakes (freshwater), seas, and oceans (saltwater).
What factors affect water quality in industrial use?
Temperature, suspended solids, bacterial count, color, odor, dissolved impurities, hardness, and alkalinity.
What are the main methods of water treatment in industries?
Disinfection, coagulation, sedimentation, filtration, water softening, and ion exchange.
Why is disinfection crucial in water treatment, and what is a common disinfectant?
Disinfection is essential for eliminating bacteria. Chlorine or hypochlorites are commonly used.
What is the purpose of coagulation in water treatment?
To aggregate non-settleable solids using coagulants like aluminum sulfate and ferric sulfate.
What is ion exchange, and what is its primary industrial use?
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.
What is the largest demand for water in manufacturing?
Heat transfer
Why is condensate reuse significant in steam production?
Reusing condensate reduces the amount of water needed.
How is water used as a raw material in industries?
As a reactant (e.g., in acetylene production), a solvent (for washing), or directly incorporated into products (e.g., beverages).
What industries commonly use water for miscellaneous purposes?
Mining, pulp and paper, sugar, and for effluent dilution or as a source of kinetic energy.
What are the four main problems associated with industrial water use?
Corrosion, deposits, biological growth, and pollution.
What factors affect the rate of corrosion in industrial systems?
Oxygen content, temperature, velocity, dissolved solids, hydrogen ion concentration, and bacteria.
What are the main causes of deposits in industrial systems?
Corrosion, precipitation of solids, and bacterial growth.
What are the classes of deposits found in industrial systems?
Sludge, scale, biological deposits, and corrosion products.
What is biological growth, and how does it affect industrial systems?
Growth of organisms like algae, fungi, and bacteria; it reduces heat exchange efficiency, contributes to corrosion, and causes odor or color issues.
What are the common methods for preventing corrosion?
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.
How is biological growth prevented in industrial systems?
By adding chlorine, chromates, or other agents like algaecides and fungicides.
What are the main pollutants found in industrial water effluent?
Insecticides, herbicides, detergents, and factory discharge.
What are the types of detergents mentioned, and which are slow to biodegrade?
ABS (branched-chain alkyl benzene sulfonates), LAS (linear alkyl benzene sulfonates), and nonionic surfactants like nonyl phenoxy ethoxylate. ABS and LAS degrade slowly.
