Physical characteristics of water.

➤Turbidity:

Water Becomes Turbid in Appearance due to presence of suspended solids. Turbidity Depends upon fineness and concentration of particles present in water. it is measured by applying nephelometry a technique to measure level of light scattered by particles at right angle to the incident light beam. scattered light level is proportional to the concentration of particles in sample.

➔The  unit of Turbidity is NTU.

➜The IS value for drinking water is 10 to 25 NTU.

There are some other measurement of Turbidity:

➧JTU:-Jackson Turbidity units which is equal to Turbidity produced by, 1 mg SiO2 in 1 L of distilled water.

➧ FTU:-Formazin Turbidity Units in this measurement SiO2 is replaced by formazin  a chemical compound (< 1 FTU ).

➤Colour:

Dissolved organic matter from vegetation or some inorganic materials may impact colour to water. it can be measured by comparing the colour of water sample with standard glass tube containing solution of different standard colour intensities.

➜The standard unit of colour is that which is produced by 1 mg of platinum cobalt dissolved in 1 L of distilled water.

➜The IS value for treated water is 5 to 25 cobalts units.

➤Taste And Odour:

Taste and Odour  can be expressed in terms of odour intensity or threshold values. A new method is flavour Profile Analysis (FPA).

Threshold Odour Number (TON)=(A+B)/A.

 

Where, A= volume of odourous water in ml.

             B=volume of odour free water in ml required to produce a 200 ml mixture.

➜As per EPA guidelines, a maximum TON is 3 for public health service.

➤Temperature:

The increase in temperature decreases palatability (acceptable to taste) ideal temperature of water for drinking purpose is 5 to 12⁰C Above 25⁰C it is not recommended.