chemical examination of water samples

Chemical Examination of water as civil engg topics

The chemical examination of water is done to reveal the sanitary quality of water. The chemical test on water involve the determination of the following :

1. Total solids in water. 

The total solid content also contains chlorides, nitrates and other compounds that cause hardness in water. The maximum permissible total solids content or TDS(total dissolved of solids) in water for domestic purposes is 500 P.P.M.(parts per million) should not be more than.

2. Hardness of water.

Hardness in water is due to the presence of bicarbonates, sulfates, chlorides and nitrates of calcium and magnesium. Hardness in water prevents soap scum and forms boiler scale. The maximum permissible hardness in water for drinking purposes is 100 P.P.M. should not be more than.

3. Chlorides in water. 

The main substance in water is sodium chloride. The excess of chloride content is dangerous and unfit for use. The maximum permissible chloride content in water for domestic supplies should not exceed 250 P.P.M.

4. chlorine in water.

 The chlorine remains as residual in treated water for sake of safety against photogenic bacterias. Chlorine is used for water purification. The maximum permissible chlorine content for public supplies should be between 0.1 to 0.2 P.P.M.  

5. p h value of water. 

The pH value indicates the hydrogen-ion concentration in the water. A hydrogen-ion concentrator is an atom or group of atoms that carries an electric charge. Calorimetric or electrometric methods are used to determine the pH value of water. The p h value of pure water for public supply is limited to 6.5 to 8. If the pH value of water is equal to 7, then the water is said to be neutral. When the pH value of water is less than 7 it represents acidic water and more than 7 represents alkaline water.

6. Iron and manganese in water. 

Iron and manganese alloys are found in water and are not objectionable if less than 0.3 ppm is present. These make the water brownish red in color and lead to the growth of micro-organisms and damage the water pipes.

7. Arsenic compounds. 

Arsenic is rarely foun in natural water. Its presence in water for domestic purposes should not be more than 0.05 P.P.M.

8. Lead metal. 

Lead is not usually found in natural water. The maximum permissible quantity of lead in water for domestic purposes is limited to 0.05 P.P.M.

9. Copper metal. 

The presence of copper is indicates pollution. The copper contents in water for domestic purposes should not be more than 3 P.P.M. The small quantity of copper is desirable for health point of view.

10. Fluorine test.

Fluorine ion is found in natural water. The maximum permissible fluorine content in water for domestic supplies should be 1.5 P.P.M.