Physical Examination of Water: Key Tests

 Physical examination of water involves various tests to assess its quality based on physical characteristics. Here are the key tests:

1. Turbidity

   • Description: Measures the clarity of water.
   • Method: Turbidity meters or nephelometers measure the scattering of light by particles in water, reported in Nephelometric Turbidity Units (NTU).
   • Significance: High turbidity indicates the presence of suspended particles, which can harbor pathogens and reduce the effectiveness of disinfection.

2. Color

   • Description: Evaluates the color of water.
   • Method: Visual comparison with standard color solutions or using a colorimeter.
   • Significance: Color can indicate the presence of organic matter, metals, or pollutants. Pure water should be colorless.

3. Odor

   • Description: Assesses the smell of water.
   • Method: Sensory evaluation by a panel or by dilution methods to determine the Threshold Odor Number (TON).
   • Significance: Odor can indicate contamination from organic compounds, industrial pollutants, or biological activity.

4. Taste

   • Description: Checks the taste of water.
   • Method: Sensory analysis by trained personnel.
   • Significance: Unpleasant taste may suggest the presence of dissolved solids, chemicals, or biological contaminants.

5. Temperature

   • Description: Measures the water temperature.
   • Method: Thermometers or digital temperature probes.
   • Significance: Temperature affects water chemistry, biological activity, and the efficiency of treatment processes. It also influences the solubility of gases like oxygen.

6. Total Dissolved Solids (TDS)

   • Description: Quantifies the combined content of all inorganic and organic substances dissolved in water.
   • Method: Conductivity meters or by evaporating a water sample and weighing the residue.
   • Significance: High TDS can affect water taste, cause scaling in pipes, and indicate the presence of various pollutants.

7. pH

   • Description: Measures the acidity or alkalinity of water.
   • Method: pH meters or pH test strips.
   • Significance: pH affects chemical reactions in water, the effectiveness of disinfection, and the corrosivity of water. Ideal drinking water has a pH between 6.5 and 8.5.

Summary

These physical tests are crucial for assessing the overall quality and safety of water. Regular monitoring helps in detecting and addressing potential contamination issues, ensuring the provision of safe and clean water for various uses.