Water & Wastewater Quality Management Notes

Water Quality Parameters

  • Total Suspended Solids (TSS): Refers to the particles suspended in water, affecting clarity.
  • Temperature: Influences chemical and biological processes in water.
  • Turbidity: Measure of water clarity, high turbidity can block sunlight.
  • Taste & Odor: Affected by various compounds in water; significant for drinking water quality.
  • Total Dissolved Solids (TDS): Sum of all dissolved substances in water.
  • Alkalinity: Indicates capacity of water to neutralize acids, vital for aquatic life.
  • Hardness: Concentration of calcium and magnesium; affects water usability.
  • Fluoride & Metals: Essential in small amounts; toxic at higher concentrations.
  • Organic Compounds: Can be biodegradable or nonbiodegradable, affecting water quality.
  • Pathogens: Disease-causing organisms must be monitored in water systems.
  • Indicators: Organisms used to gauge the level of pollution.
  • Nutrients: Critical for growth; nitrogen and phosphorus are key limiting factors.

Chemical Parameters

1. Fluoride & Metals
  • Fluoride:
    • Found in groundwater, can prevent dental issues at concentrations around 1.0 mg/L.
    • Excess can lead to fluorosis.
  • Metals:
    • Nontoxic Metals: Sodium, aluminum, manganese, iron can affect taste and color.
    • Toxic Metals: Arsenic, mercury, lead are harmful to organisms.
2. Organic Compounds
  • Biodegradable Organics: Substances like starches and fats that microorganisms can decompose.
    • Can affect taste, color, odor; oxidation processes differ in aerobic vs anaerobic environments.
3. Biochemical Oxygen Demand (BOD)
  • BOD: Oxygen required by bacteria to decompose organic material under aerobic conditions.
    • Measured in a controlled environment over 5 days (BOD5).
    • Formula:
      BOD=DO<em>I−DO</em>FPBOD = \frac{DO<em>I - DO</em>F}{P}
      where
    • $DO_I$: Initial dissolved oxygen
    • $DO_F$: Final dissolved oxygen
    • $P$: Decimal fraction of the sample.
  • Factors affecting BOD: Temperature, TDS, pressure.
4. Nutrients
  • Nitrogen: Vital for protein synthesis; converted to ammonia (NH3) then nitrates.
  • Phosphorus: Present as phosphates; key in studies of water quality.

Biological Parameters

  • Presence/absence of certain organisms informs on water quality.
1. Pathogens
  • Disease-causing organisms (e.g., bacteria like Vibrio cholerae, viruses, helminths).
2. Indicator Organisms
  • Used to indicate pollution, e.g., fecal coliforms detect the presence of pathogens.
3. Testing Methods for Pathogens
  • Membrane Filtration: Rapid method to count coliforms.
  • Multiple-tube Fermentation Test: Uses MPN method to estimate coliforms in water.

Summary

  • Water quality management combines physical, chemical, and biological monitoring to ensure safe and healthy water for humans and ecosystems. Focus on parameters such as TSS, BOD, nutrients, and pathogen presence is essential for effective management and treatment. Understanding these factors aid in addressing potential pollution and maintaining water safety standards.