Unit I: Water Treatment and Analysis

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.

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.