40 Questions
What percentage of the Earth's surface is water?
71%
What percentage of the Earth's water supply is in the ocean?
97%
What percentage of the Earth's water supply is available as fresh water?
1%
Why is the ocean water unfit for human consumption?
Due to its high salt content
What is true about pure water?
It is colorless, tasteless, and odorless
Why is there no such thing as 'pure water' in nature?
Because it always contains chemical and biological impurities
What is an important characteristic of water?
It is an excellent solvent
What is the main reason for water shortages in the past?
Climatic changes
What is the main cause of millions of deaths every year?
Water-borne diseases
What is the importance of water in human life?
It is necessary for irrigation, industry, domestic needs, shipping, and sanitation
What is one of the parameters used to measure water quality?
Turbidity
What determines the size of the various units in a water treatment plant?
Quantity of water to be provided
What is the design capacity of a water treatment plant based on?
Maximum day demand
What is used to forecast population for water demand?
Both mathematical and graphical methods
What determines which unit operations and processes are to be provided for a water treatment plant?
Quality of the untreated water and quality of the product water
What is the purpose of forecasting population in water treatment plant design?
To determine the water demand
What is the purpose of measuring biochemical oxygen demand (BOD) in water?
To measure the concentration of oxygen required by microorganisms
What is one of the factors that determines the hydraulic design of a water treatment plant?
Quantity of water to be provided
What is a measure of the cloudiness or haziness of water?
Turbidity
What is the purpose of determining the per capita water usage?
To determine the water demand
What is water pollution?
The presence of impurities in water that impair its use for a designated purpose
What is a point source of water pollution?
A single location that discharges effluents into a waterbody
What is a non-point source of water pollution?
A scattered source of pollution that does not have a specific location
Who sets the Drinking Water Standards in the US?
The US Environmental Protection Agency (EPA)
What are Primary Drinking Water Standards?
Enforceable standards that protect public health by limiting contaminants
What are Secondary Standards of drinking water?
Non-enforceable guidelines for contaminants that may cause cosmetic effects
Which of the following is a type of contaminant regulated by Primary Drinking Water Standards?
Heavy metals
Which of the following is a type of contaminant regulated by Secondary Standards of drinking water?
Chloride
What is the main purpose of setting drinking water standards?
To protect public health by limiting contaminants in drinking water
What is the result of water pollution?
The water becomes less useful for its intended purpose
What is the main assumption in the Geometric Increase Method (GIM)?
The percentage increase in population from decade to decade is constant
Which type of city is the Geometric Increase Method (GIM) applicable to?
Young and rapidly growing city
What is the formula to calculate the population at the end of n years or decades using the Geometric Increase Method (GIM)?
pn = po × (1 + 𝑥̅/100)^n
What is the main assumption in the Arithmetic Increase Method (AIM)?
The rate of change in population with time is constant
Which type of city is the Arithmetic Increase Method (AIM) applicable to?
Old and large city with no more industrial growth
What is the formula to calculate the population after n decades using the Arithmetic Increase Method (AIM)?
pn = po + n𝑥̅
If the percentage increase in population from decade to decade is increasing, what type of city is it?
Young and rapidly growing city
What does the term 𝑥̅ represent in the Geometric Increase Method (GIM)?
Average percentage increase in population
What is the main difference between the Geometric Increase Method (GIM) and the Arithmetic Increase Method (AIM)?
All of the above
When is the Arithmetic Increase Method (AIM) used?
When the rate of change in population with time is constant
Study Notes
Water Pollution
- Water is the most important natural resource and the second most important constituent of life-support systems.
- 71% of the Earth's surface is water, and 29% is land.
- 97% of the Earth's water supply is in the ocean, which is unfit for human consumption due to its high salt content.
- Only 1% of the Earth's water is fresh and available for human consumption.
Pure Water and Impurities
- Pure water is colorless, tasteless, and odorless.
- Water is an excellent solvent that can dissolve most minerals it comes into contact with.
- There is no such thing as "pure water" in nature, as it always contains chemical and biological impurities.
Water Pollution Definition and Sources
- Water pollution is the presence of impurities in such quantity and nature that it impairs the use of water for designated purposes.
- Point sources of water pollution are specific sites that directly discharge effluents into water bodies, such as industries, power plants, and offshore oil wells.
- Non-point sources of water pollution are scattered and include surface run-off from agricultural fields, overflowing small drains, and atmospheric deposition.
Water Quality Standards
- The US Environmental Protection Agency (EPA) sets drinking water standards for drinking water.
- Primary drinking water standards are enforceable and limit the levels of contaminants in drinking water, including inorganic chemicals, agricultural pesticides, organic chemicals, radionuclides, and microorganisms.
- Secondary standards are non-enforceable guidelines that establish recommendations for contaminants that may cause cosmetic effects or aesthetic effects.
Measurement of Water Quality
- Water quality is measured by parameters such as dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, total organic carbon, turbidity, color, taste, and odor, pH, alkalinity, solids, nitrogen and phosphor, pathogens, and heavy metals.
Water Treatment Plant
- The design of a water treatment plant requires knowledge of the quantity of water to be provided, the quality of the untreated or raw water, and the quality required for the product water.
- The quantity of water to be provided determines the size of the various units and processes to be provided.
Water Demand Forecasting
- Water demand forecasting is necessary to determine the design capacity of a water treatment plant.
- Forecasting methods include geometric increase method, arithmetic increase method, incremental increase method, decrease rate of growth method, graphical extension method, and graphical comparison method.
- Geometric increase method is used for young and rapidly growing cities, while arithmetic increase method is used for old and large cities with no more industrial growth.
Learn about the importance of water and its role in the life-support system. Explore the various uses of water, including irrigation, industry, domestic needs, and sanitation.
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