Water Quality Parameters and Composition
Understanding the importance of water quality and its parameters
Water Quality Parameters
- Chemical Oxygen Demand (COD) measures organic matter
- Biochemical Oxygen Demand (BOD) measures biologically degradable organic matter
- Dissolved Oxygen (DO) indicates the health of a river
- Other parameters include pH, temperature, and turbidity
Chemical Oxygen Demand (COD)
- Measures the amount of oxygen needed to fully oxidize organic matter
- Indirect method to assess organic pollution in water
- Excess potassium dichromate is used as a strong oxidizing agent
- COD limit for effluent discharge to receiving water bodies: 250 mg/L
Biochemical Oxygen Demand (BOD)
- Assesses biologically degradable organic matter in a water sample
- Uses the rate of dissolved oxygen depletion by microorganisms
- BOD limit for effluent discharge to inland surface water: 30 mg/L
- BOD limit for drinking water supply: 2 mg/L
Dissolved Oxygen (DO)
- Indicates the amount of oxygen dissolved in water
- Critical for the survival of aquatic organisms
- Optimum DO range for sustaining life: 7-9 mg/L
- Below 5 mg/L, many fish species cannot survive
Other Water Quality Parameters
- pH: Measures the acidity or alkalinity of water
- Temperature: Influences biological activity in water bodies
- Turbidity: Indicates the clarity of water
- Composite sampling reveals overall water quality
Composition of Natural Water Systems
- Rainwater: Diluted form of seawater, pH affected by dissolved CO2
- River Water: Determined by precipitation and rocks/minerals
- Seawater: Higher sodium and chloride concentrations, calcium reduced
- Groundwater: High in bioorganic matter, influenced by minerals
Conclusion
- Water quality parameters play a crucial role in assessing water health
- COD measures organic pollution, BOD assesses biologically degradable organic matter, and DO indicates oxygen availability
- Understanding the composition of natural water systems helps identify sources of pollution
- Maintaining water quality is essential for the well-being of ecosystems and human populations