Unit I: Water Treatment and Analysis
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Questions and Answers

What is a significant advantage of the cation and anion exchange process?

  • It can soften highly acidic or alkaline water. (correct)
  • It removes all organic matter completely.
  • It is a low-cost method for water treatment.
  • It successfully reduces turbidity to any level.

    • Which component is necessary for activating anion exchanges?

  • Regular tap water
  • Mineral acid like HCl
  • Concentrated NaOH solution
  • Diluted NaOH solution (correct)

    • What is the primary function of reverse osmosis?

  • Remove only ionic hardness from water.
  • Stop the osmosis phenomenon entirely.
  • Remove hardness from sea water. (correct)
  • Force solvent molecules from concentrated to diluted solutions.

    • What is a common disadvantage associated with the cation and anion exchange process?

    <p>It necessitates costly equipment and chemicals.</p> Signup and view all the answers

    What material is commonly used for the membrane in reverse osmosis systems?

    <p>Cellulose acetate</p> Signup and view all the answers

    What percentage of the Earth's water is considered fresh and usable by humans?

    <p>1%</p> Signup and view all the answers

    Which of the following is NOT considered a type of impurity present in water?

    <p>Geological impurities</p> Signup and view all the answers

    What type of hardness is associated with the presence of bicarbonates of calcium and magnesium?

    <p>Temporary hardness</p> Signup and view all the answers

    Which of the following can cause a bitter taste in water?

    <p>Presence of sulphates</p> Signup and view all the answers

    What is typically the cause of turbid water?

    <p>Colloidal suspensions</p> Signup and view all the answers

    Which of the following represents biological impurities in water?

    <p>Fungi and viruses</p> Signup and view all the answers

    What effect does hard water have on soap usage?

    <p>It creates a white scum with soap</p> Signup and view all the answers

    What is the primary consequence of using water with high levels of biological impurities?

    <p>Potential health risks</p> Signup and view all the answers

    What is the primary problem caused by using hard water in the laundry?

    <p>Coloration of clothes due to iron salts</p> Signup and view all the answers

    Which of the following describes the effect of sulphates in the sugar refining process?

    <p>Causes difficulties in crystallization</p> Signup and view all the answers

    What is foaming in the context of boiler operation?

    <p>Formation of stable bubbles at the water surface</p> Signup and view all the answers

    What is the main disadvantage of scale formation in boilers?

    <p>Causes loss of heat and fuel</p> Signup and view all the answers

    Which of the following methods can be used to prevent priming in boilers?

    <p>Fitting mechanical steam purifiers</p> Signup and view all the answers

    What causes the formation of sludge in a boiler?

    <p>Increased concentration of dissolved and suspended solids</p> Signup and view all the answers

    What chemical can be added to reduce foaming in boilers?

    <p>Castor oil</p> Signup and view all the answers

    Which of the following salts primarily causes scale deposits in a boiler?

    <p>Ca(HCO3)2</p> Signup and view all the answers

    Which approach can help remove scale deposits in a boiler?

    <p>Mechanical scraping and chemical treatments</p> Signup and view all the answers

    What negatively impacts the crystallization of sugar during refining?

    <p>Presence of iron salts</p> Signup and view all the answers

    What is the cause of permanent hardness in water?

    <p>Presence of chlorides and sulfates of heavy metals</p> Signup and view all the answers

    Which of the following methods is used to determine water hardness?

    <p>EDTA titration</p> Signup and view all the answers

    Which unit is NOT a standard measure for expressing water hardness?

    <p>Degrees Celsius (°C)</p> Signup and view all the answers

    What happens when hard water is used for washing clothes?

    <p>It produces sticky precipitates that reduce lather</p> Signup and view all the answers

    What is the primary reason for using calcium carbonate (CaCO3) as a standard in hardness calculations?

    <p>It has a molecular weight that simplifies calculations</p> Signup and view all the answers

    What is a disadvantage of hard water when used for cooking?

    <p>It can cause deposits in cooking utensils</p> Signup and view all the answers

    The permanent hardness of water can best be determined by:

    <p>Subtracting temporary hardness from total hardness</p> Signup and view all the answers

    Why is there an increased risk of forming calcium oxalate crystals with hard water?

    <p>Increased calcium concentrations promote crystal formation</p> Signup and view all the answers

    What color indicates the endpoint of the EDTA titration for hardness testing?

    <p>Blue</p> Signup and view all the answers

    Which of the following salts can contribute to permanent hardness in water?

    <p>Magnesium chloride</p> Signup and view all the answers

    What chemical reaction defines caustic embrittlement in boilers?

    <p>Na2CO3 + H2O → NaOH + CO2</p> Signup and view all the answers

    Which of the following is NOT a method for preventing caustic embrittlement?

    <p>Implementing mechanical de-aeration</p> Signup and view all the answers

    What is the main reason for boiler corrosion mentioned?

    <p>Dissolved oxygen reacting with boiler materials</p> Signup and view all the answers

    What compound is formed when sodium sulfite reacts with dissolved oxygen?

    <p>Na2SO4</p> Signup and view all the answers

    Which process is described as the zeolite process?

    <p>Ion exchange of sodium ions for calcium or magnesium ions</p> Signup and view all the answers

    How is exhausted zeolite regenerated?

    <p>By heating it with brine solution</p> Signup and view all the answers

    What is one disadvantage of the zeolite process?

    <p>It cannot remove colored ions like Fe2+ and Mn2+</p> Signup and view all the answers

    What type of resins are used in cation exchange processes?

    <p>Polymers containing acidic functional groups</p> Signup and view all the answers

    Which of the following is a chemical reaction for removing dissolved carbon dioxide from water?

    <p>2NH4OH + CO2 → (NH4)2CO3</p> Signup and view all the answers

    What occurs when hard water is treated with anion exchange resins?

    <p>Hydroxide ions are substituted for anions like sulfate and chloride</p> Signup and view all the answers

    What is the primary purpose of applying pressure in reverse osmosis?

    <p>To push solvent molecules from lower concentration to higher concentration</p> Signup and view all the answers

    Which of the following is an advantage of the cation and anion exchange process?

    <p>It produces very low hardness water suitable for high pressure boilers</p> Signup and view all the answers

    What is a common disadvantage of using reverse osmosis?

    <p>It has a limited membrane lifespan of 2-4 years</p> Signup and view all the answers

    What must be the turbidity level of water for effective cation and anion exchange treatment?

    <p>Below 10 ppm</p> Signup and view all the answers

    Which materials have recently been used for membranes in reverse osmosis systems?

    <p>Polythacrylate and polyamide polymer</p> Signup and view all the answers

    What is the primary cause of turbidity in water?

    <p>Colloidal suspensions of insoluble substances</p> Signup and view all the answers

    Which type of impurity is characterized by metallic substances causing color in water?

    <p>Physical impurities</p> Signup and view all the answers

    Temporary hardness in water can be effectively removed by which method?

    <p>Boiling</p> Signup and view all the answers

    What percentage of water on Earth's surface is classified as fresh water?

    <p>3%</p> Signup and view all the answers

    Which of the following is NOT a common inorganic cation found in chemical impurities in water?

    <p>CCl-</p> Signup and view all the answers

    Which of the following substances can lead to a bitter taste in water?

    <p>Iron</p> Signup and view all the answers

    Biological impurities in water include which of the following?

    <p>Fungi and viruses</p> Signup and view all the answers

    What is the major consequence of using hard water in household cleaning?

    <p>Difficulty in lathering soap</p> Signup and view all the answers

    What is the primary cause of caustic embrittlement in boilers?

    <p>Concentration of NaOH in cracks</p> Signup and view all the answers

    Which method is effective in removing dissolved oxygen from boiler water?

    <p>Mechanical de-aeration</p> Signup and view all the answers

    What is a significant disadvantage of the zeolite process for softening water?

    <p>Produces excessive sodium ions</p> Signup and view all the answers

    What is the outcome of the reaction between magnesium bicarbonate and heat in a boiler?

    <p>Formation of magnesium carbonate and water</p> Signup and view all the answers

    Which component is added to boiler water to block hair cracks and pits?

    <p>Tannin or lignin</p> Signup and view all the answers

    What indicates the presence of dissolved carbon dioxide in boiler water?

    <p>Creation of carbonic acid</p> Signup and view all the answers

    What is the purpose of using sodium phosphate as a softening agent?

    <p>Inhibits scale formation</p> Signup and view all the answers

    Which of the following compounds can lead to boiler corrosion via chemical attack?

    <p>Dissolved oxygen</p> Signup and view all the answers

    What change occurs during the regeneration of exhausted zeolite?

    <p>Exchange of sodium with calcium</p> Signup and view all the answers

    What is the overall effect of using ion exchange in water treatment?

    <p>It produces de-ionized water through ion exchange</p> Signup and view all the answers

    What effect do iron and manganese salts in water have on fabrics?

    <p>They cause colored spots on the fabrics.</p> Signup and view all the answers

    What issue arises in the sugar refining process when water contains certain salts?

    <p>It complicates the crystallization of sugar.</p> Signup and view all the answers

    Which issue is directly caused by the presence of hard water in dyeing processes?

    <p>Formation of undesirable precipitates.</p> Signup and view all the answers

    What is a common consequence of using hard water in the laundry process?

    <p>It causes much of the soap to be wasted.</p> Signup and view all the answers

    What complication does hard water cause in steam generation within boilers?

    <p>It leads to scale and sludge formation.</p> Signup and view all the answers

    What is foaming in boiler operations primarily caused by?

    <p>The presence of oil drops and grease.</p> Signup and view all the answers

    Which method helps in preventing the formation of sludge in boilers?

    <p>Employing soft water free from dissolved salts.</p> Signup and view all the answers

    What type of deposits are referred to as 'scale' in boiler systems?

    <p>Hard, sticky deposits.</p> Signup and view all the answers

    What causes the formation of scale in boilers when water is heated?

    <p>Decomposition of certain salts at high temperatures.</p> Signup and view all the answers

    How can softening of boiler feed water be defined?

    <p>The removal of calcium and magnesium salts.</p> Signup and view all the answers

    What is permanent hardness primarily caused by?

    <p>Chlorides and sulfates of heavy metals</p> Signup and view all the answers

    Which unit of hardness represents the number of parts of calcium carbonate equivalent hardness in 106 parts of water?

    <p>Parts per Million (ppm)</p> Signup and view all the answers

    What color indicates the endpoint of the EDTA titration for measuring water hardness?

    <p>Blue</p> Signup and view all the answers

    What happens to the soap when hard water is used for washing?

    <p>It forms sticky precipitates</p> Signup and view all the answers

    Which method is commonly used to determine the total hardness of water?

    <p>EDTA titration method</p> Signup and view all the answers

    Which of the following is NOT an indicator of hard water when cooking?

    <p>Enhanced flavor in cooked dishes</p> Signup and view all the answers

    What does the term 'temporary hardness' refer to?

    <p>Hardness that can be removed by boiling</p> Signup and view all the answers

    Which chemical reaction occurs with magnesium bicarbonate upon heating?

    <p>Conversion to magnesium hydroxide</p> Signup and view all the answers

    What disadvantage does hard water present in domestic use during bathing?

    <p>It produces sticky scum</p> Signup and view all the answers

    Which of the following accurately describes a component of water hardness formulation?

    <p>CaCl2 contributes to permanent hardness</p> Signup and view all the answers

    Study Notes

    Introduction to Water Treatment

    • Water is vital for life, used in various domains including drinking, sanitation, and industry.
    • Only 3% of Earth's water is freshwater; 69% in glaciers, 30% underground, and less than 1% in surface bodies (lakes, rivers, etc.).
    • Usable fresh water is predominantly found underground.

    Types of Impurities in Water

    • Physical Impurities:

      • Color: Caused by metallic substances.
      • Turbidity: Result of fine suspensions like clay and microorganisms.
      • Taste: Influenced by dissolved minerals such as iron and aluminum.
      • Odor: Undesirable smell affecting domestic and industrial use.

    • Chemical Impurities:

      • Inorganic Chemicals: Includes cations (Al³⁺, Ca²⁺) and anions (Cl⁻, SO₄²⁻).
      • Organic Chemicals: Composed of dyes, fuels, pesticides, and detergents.

    • Biological Impurities:

      • Consist of algae, bacteria, fungi, viruses, and parasites.

    Water Hardness

    • Hard Water: Inhibits lathering with soap and produces white scum. Divided into:
      • Temporary Hardness: Due to bicarbonates of calcium and magnesium; removable by boiling.
      • Permanent Hardness: Caused by chlorides and sulfates of certain metals; cannot be removed by boiling.

    Measurement Units for Hardness

    • Parts per Million (ppm): Measures hardness relative to 1,000,000 parts of water.
    • Milligrams per Liter (mg/L): Equivalent to ppm, 1 mg/L equals 1 mg of hardness in 1 liter.
    • Clark’s Degree (°Cl): 1° Clarke = 1 part of CaCO₃ per 70,000 parts of water.
    • Degree French (°Fr): 1° Fr = 1 part of CaCO₃ per 100,000 parts of water.

    Hardness Determination

    • EDTA Method: Involves titration with EDTA using EBT indicator. Color change from wine red to blue indicates endpoint.
    • Calculate total hardness as the sum of permanent and temporary hardness.

    Disadvantages of Hard Water

    • Affects domestic use:

      • Washing: Difficult lathering, waste of soap, and stains on fabrics.
      • Cooking: Requires more fuel and time, affects taste of beverages.
      • Drinking: Can adversely affect digestion and health.

    • Impacts industrial use:

      • Textile: Reduces lathering and leads to poor dye quality.
      • Sugar: Complicates sugar crystallization.
      • Dyeing: Causes undesired color results.
      • Others including paper, laundry, concrete, and pharmaceuticals.

    Boiler Issues Due to Hard Water

    • Priming: Water droplets carried with steam due to rapid boiling and high velocity; can be prevented by maintaining low water levels.
    • Foaming: Stable bubbles are often caused by impurities, leading to similar issues as priming; treat with antifoaming agents.
    • Scale and Sludge Formation: Hard deposits (scale) and slimy deposits (sludge) on boiler walls reduce efficiency; prevent with soft water, blow down operations, and regular maintenance.
    • Caustic Embrittlement: Caused by sodium carbonate in high-pressure environments, leading to cracks; prevention involves using softening agents like sodium phosphate.
    • Corrosion: Caused by dissolved oxygen and carbon dioxide; treated through chemical processes such as adding sodium sulfite and mechanical de-aeration.

    Boiler Water Treatment Methods

    • Zeolite/Permutit Process: Ion exchange process removing hardness-causing ions; can regenerate with brine solution.
    • Ion Exchange Process: Uses cationic and anionic resins for deionization; exchanges hardness ions for hydrogen and hydroxide ions respectively.

    Summary of Water Treatment Methods

    • Zeolite Method: Removes calcium and magnesium ions; simple and cost-effective but can produce excess sodium ions.
    • Ion Exchange Method: Effective demineralization but involves complex setup and maintenance.### Ion Exchange Processes
    • R1 OH and Cl- react to form R1Cl and OH- with the output being de-ionised water after ion exchanges are exhausted.
    • Cation exchanges are activated by mineral acids like HCl, while anion exchanges use dilute NaOH solution.
    • Reaction: R2 Ca + 2H+ → 2RH + Ca²+ indicating calcium ions are removed through cation exchange.

    Ion Exchange Reactions

    • Reaction: R1 SO + 2OH- → 2R1OH + SO²- demonstrates the regeneration of hydroxides in the process.

    Advantages of Ion Exchange

    • Effective for softening highly acidic or alkaline water.
    • Produces water with very low hardness, suitable for high-pressure boilers.

    Disadvantages of Ion Exchange

    • Equipment and required chemicals can be costly.
    • Turbidity levels must be below 10 ppm for optimal output; higher turbidity reduces effectiveness.

    Reverse Osmosis (RO)

    • Osmosis occurs when solvent molecules move from lower to higher concentration across a semi-permeable membrane.
    • Osmotic pressure counteracts this movement; applying excess pressure induces reverse osmosis, forcing solvent from high to low concentration.
    • RO is effective in removing hardness from seawater.

    Reverse Osmosis Process

    • Pressure of 15-49 kg/cm² is applied to seawater to produce pure water through a semi-permeable membrane.
    • Membranes made from cellulose acetate are commonly used; advancements include polythacrylate and polyamide.

    Advantages of Reverse Osmosis

    • Effectively removes colloidal silica.
    • Eliminates both ionic and non-ionic high molecular weight organic matter.
    • Membrane replacement is straightforward, ensuring continuous water supply.
    • Membrane lifespan ranges from 2 to 4 years, facilitating regular maintenance.

    Introduction to Water Treatment

    • Water is vital for life, used in various domains including drinking, sanitation, and industry.
    • Only 3% of Earth's water is freshwater; 69% in glaciers, 30% underground, and less than 1% in surface bodies (lakes, rivers, etc.).
    • Usable fresh water is predominantly found underground.

    Types of Impurities in Water

    • Physical Impurities:

      • Color: Caused by metallic substances.
      • Turbidity: Result of fine suspensions like clay and microorganisms.
      • Taste: Influenced by dissolved minerals such as iron and aluminum.
      • Odor: Undesirable smell affecting domestic and industrial use.

    • Chemical Impurities:

      • Inorganic Chemicals: Includes cations (Al³⁺, Ca²⁺) and anions (Cl⁻, SO₄²⁻).
      • Organic Chemicals: Composed of dyes, fuels, pesticides, and detergents.

    • Biological Impurities:

      • Consist of algae, bacteria, fungi, viruses, and parasites.

    Water Hardness

    • Hard Water: Inhibits lathering with soap and produces white scum. Divided into:
      • Temporary Hardness: Due to bicarbonates of calcium and magnesium; removable by boiling.
      • Permanent Hardness: Caused by chlorides and sulfates of certain metals; cannot be removed by boiling.

    Measurement Units for Hardness

    • Parts per Million (ppm): Measures hardness relative to 1,000,000 parts of water.
    • Milligrams per Liter (mg/L): Equivalent to ppm, 1 mg/L equals 1 mg of hardness in 1 liter.
    • Clark’s Degree (°Cl): 1° Clarke = 1 part of CaCO₃ per 70,000 parts of water.
    • Degree French (°Fr): 1° Fr = 1 part of CaCO₃ per 100,000 parts of water.

    Hardness Determination

    • EDTA Method: Involves titration with EDTA using EBT indicator. Color change from wine red to blue indicates endpoint.
    • Calculate total hardness as the sum of permanent and temporary hardness.

    Disadvantages of Hard Water

    • Affects domestic use:

      • Washing: Difficult lathering, waste of soap, and stains on fabrics.
      • Cooking: Requires more fuel and time, affects taste of beverages.
      • Drinking: Can adversely affect digestion and health.

    • Impacts industrial use:

      • Textile: Reduces lathering and leads to poor dye quality.
      • Sugar: Complicates sugar crystallization.
      • Dyeing: Causes undesired color results.
      • Others including paper, laundry, concrete, and pharmaceuticals.

    Boiler Issues Due to Hard Water

    • Priming: Water droplets carried with steam due to rapid boiling and high velocity; can be prevented by maintaining low water levels.
    • Foaming: Stable bubbles are often caused by impurities, leading to similar issues as priming; treat with antifoaming agents.
    • Scale and Sludge Formation: Hard deposits (scale) and slimy deposits (sludge) on boiler walls reduce efficiency; prevent with soft water, blow down operations, and regular maintenance.
    • Caustic Embrittlement: Caused by sodium carbonate in high-pressure environments, leading to cracks; prevention involves using softening agents like sodium phosphate.
    • Corrosion: Caused by dissolved oxygen and carbon dioxide; treated through chemical processes such as adding sodium sulfite and mechanical de-aeration.

    Boiler Water Treatment Methods

    • Zeolite/Permutit Process: Ion exchange process removing hardness-causing ions; can regenerate with brine solution.
    • Ion Exchange Process: Uses cationic and anionic resins for deionization; exchanges hardness ions for hydrogen and hydroxide ions respectively.

    Summary of Water Treatment Methods

    • Zeolite Method: Removes calcium and magnesium ions; simple and cost-effective but can produce excess sodium ions.
    • Ion Exchange Method: Effective demineralization but involves complex setup and maintenance.### Ion Exchange Processes
    • R1 OH and Cl- react to form R1Cl and OH- with the output being de-ionised water after ion exchanges are exhausted.
    • Cation exchanges are activated by mineral acids like HCl, while anion exchanges use dilute NaOH solution.
    • Reaction: R2 Ca + 2H+ → 2RH + Ca²+ indicating calcium ions are removed through cation exchange.

    Ion Exchange Reactions

    • Reaction: R1 SO + 2OH- → 2R1OH + SO²- demonstrates the regeneration of hydroxides in the process.

    Advantages of Ion Exchange

    • Effective for softening highly acidic or alkaline water.
    • Produces water with very low hardness, suitable for high-pressure boilers.

    Disadvantages of Ion Exchange

    • Equipment and required chemicals can be costly.
    • Turbidity levels must be below 10 ppm for optimal output; higher turbidity reduces effectiveness.

    Reverse Osmosis (RO)

    • Osmosis occurs when solvent molecules move from lower to higher concentration across a semi-permeable membrane.
    • Osmotic pressure counteracts this movement; applying excess pressure induces reverse osmosis, forcing solvent from high to low concentration.
    • RO is effective in removing hardness from seawater.

    Reverse Osmosis Process

    • Pressure of 15-49 kg/cm² is applied to seawater to produce pure water through a semi-permeable membrane.
    • Membranes made from cellulose acetate are commonly used; advancements include polythacrylate and polyamide.

    Advantages of Reverse Osmosis

    • Effectively removes colloidal silica.
    • Eliminates both ionic and non-ionic high molecular weight organic matter.
    • Membrane replacement is straightforward, ensuring continuous water supply.
    • Membrane lifespan ranges from 2 to 4 years, facilitating regular maintenance.

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    Explore the vital role of water in various aspects of life and industry in this detailed quiz on water treatment and analysis. Discover its significance in drinking, sanitation, agriculture, and industrial processes. Delve into the complexities of water distribution and its essential functions in our environment.

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