30 Questions
Which method is used to determine the hardness of water in a simple and inexpensive way?
EDTA Titration
What is the main purpose of a water softener?
To remove minerals that cause water hardness
Why is softening not usually part of the treatment process for surface waters?
Because surface waters seldom have hardness levels above 200 mg/L as CaCO3
What is the result of geological formations of the water source?
Water hardness
Why is softening more common for groundwater than surface water?
Because groundwater has higher hardness levels
What is the reason for not having a single criterion for maximum hardness in public water supplies?
Because hardness levels vary widely
What is the formula used to calculate the basin surface area of a circular clarifier?
Ab = (pi)*r2
What is the average detention time of the primary clarifier in Example 3?
2.5 hours
What is the average overflow rate of the primary clarifier in Example 3?
20 m3/day per square meter
What is the primary function of filtration in water treatment?
To remove small particles from water
What is typically used to make granular filters in water treatment?
Sand, gravel, and crushed coal
What is the shape of the clarifier being designed in Example 3?
Circular
What is the purpose of adding chlorine to water in a treatment process?
To kill any disease-causing organisms
Which of the following disinfectants is used for physical disinfection of water?
Ultraviolet light
What is the unit of measurement used to express the concentration of ions or chemicals in solution?
Milligrams per liter
What is the meaning of the term 'parts per million' in the context of water treatment?
One part by weight to 1 million parts by volume
Which of the following is NOT a disinfectant used for chemical disinfection of water?
Ultraviolet light
What is the unit of measurement used to express the amount of chlorine added to water?
Milligrams per liter
What is the primary difference between carbonate hardness and non-carbonate hardness?
The ability to be removed by boiling
Which of the following compounds is an example of a non-carbonate hardness compound?
Calcium sulfate
What is the effect of dissolved salts on the boiling point of water?
It increases the boiling point
What is the characteristic of hard water in terms of soap usage?
It requires a large quantity of soap for washing
What is the term for the type of hardness that can be removed by boiling?
Temporary hardness
What is the conventional practice for calculating water hardness?
Using the concept of equivalents and equivalent weights
What is the primary purpose of aeration in groundwater treatment?
To remove dissolved gases, such as carbon dioxide and hydrogen sulfide
Which of the following processes is not used in individual home units for softening water?
Lime-soda ash process
What is the purpose of coagulation/flocculation in groundwater treatment?
To form large particles of floc that can be easily separated from the water
What is the purpose of sedimentation in groundwater treatment?
To allow the flocs to settle and be separated from the water
What is the primary cause of hardness in water?
Calcium and magnesium ions
What is the primary purpose of softening in groundwater treatment?
To remove hardness caused by calcium and magnesium ions
Test your knowledge of water hardness classification, including the different types of cations and anions, and the compounds that contribute to water hardness. Learn about carbonate and non-carbonate hardness compounds, and how they are classified. This quiz is perfect for students of chemistry, environmental science, and engineering.
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