Water Technology and Cycle Quiz

Water Technology

• Water is a valuable natural resource, found in different forms in the environment.
• Water scarcity is a global issue due to increasing population, economic growth, and climate change
• Fresh water is limited and vulnerable.
• Lack of clean, fresh water impacts poverty reduction, national development, health, productivity, food security, and economic development.

Water Cycle/Hydrological Cycle

• The water cycle is the movement of water on, above and below the surface of the Earth.

Water Distribution on Earth

• Approximately 71% of the Earth's surface is covered by water, with only 2.5% of it being fresh water.
• Of the fresh water, about 68.7% is locked up in glaciers and ice caps.
• Only 0.3% of the world's water is available for human use.

Sources of Water

• Surface water, groundwater, and collected rainwater are the main sources of water for drinking, washing, agriculture, and industry.
• Surface water is located on the Earth's surface in rivers, creeks, wetlands, and reservoirs. It is produced by precipitation and water runoff.
• Groundwater is found below the Earth's surface, accessed through springs and wells.
• Rainwater is collected from roofs or other hard surfaces and can provide a valuable water source.

Hardness of Water

• Hardness is a measure of the concentration of multivalent cations in water, primarily calcium (Ca2+) and magnesium (Mg2+).
• Hard water prevents the lathering of soap due to the formation of insoluble salts of calcium and magnesium.
• Other multivalent cations such as Fe3+, Sr2+, Zn2+, and Mn2+ also contribute to water hardness.

Types of Hardness

• Temporary or Carbonate Hardness is caused by dissolved bicarbonates, carbonates, and hydroxides of calcium, magnesium, iron, and other heavy metals.
• Permanent or Non-Carbonate Hardness is not easily removed by boiling.

Hardness in terms of Calcium Carbonate Equivalents

• Hardness is calculated in terms of CaCO3 equivalents because it is the most common insoluble impurity in water and its molecular weight is 100, making calculations easier.
• The equivalent of CaCO3 is calculated as: Mass of the substance * Equivalent wt.of CaCO3 /Equivalent wt.of the substance

Units of Hardness

• Parts per Million (ppm): Parts of CaCO3 equivalent hardness per 106 parts of water.
• mg/L: Milligrams of CaCO3 equivalent hardness per liter of water.
• Degree Clarke (oCl): Parts of CaCO3 equivalent hardness per 70,000 parts of water.
• Degree French (oFr): Parts of CaCO3 equivalent hardness per 105 parts of water.

Numerical Example Calculation of Hardness

• Total hardness is calculated by summing the CaCO3 equivalents of all hardness-causing substances in the water sample.
• Temporary hardness is the sum of the CaCO3 equivalents of the bicarbonates.
• Permanent hardness is the difference between total hardness and temporary hardness.

Conclusion

• Understanding water hardness is crucial for effective water treatment processes, as it affects the quality of water for drinking, washing, and industrial uses.
• Properly managing water hardness is important for ensuring safe and efficient water use.

Test your knowledge on water technology, the water cycle, and the distribution of water on Earth. Explore important concepts relating to water scarcity, sources of fresh water, and the impact of water availability on human life and development. This quiz is essential for understanding the significance of water as a natural resource.