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9 Mar 2014

physical characterstics of water

  1. Turbidity 
when the large suspanded matter such as clay or silt and other muddy cloudy turbits are prresent in the water,it showas the turbityof water.

  • turbity or raw water is measured by turbidity rod / turbidometer
  • The standard unit of turbidity is mg/l or ppm 
  • the unit of turbidity 1 mg silica divided by 1 litre of distilled water
  • turbidity for drinking water is vary 5 to 10 units
  • turbity in clear lake is about 25 units
  • And for muddy lake is about 100 units
2. Colour
  • The desolve organic matter from decay and inorganic matter such as coloured soil may impart to the colour to water.
  • The excessive growth of algae and adequatic micro-organism also impart colour to the
  • however the colour of water concidered objectionable from phychological point of view
  • The colour or water from the health of view is not objectionable 
  • But colour may spoil cloth being washed
  • The standart unit of colour is1 mg platinum cobalt dessolved in one litre distilled water
  • the maximum permissible colour for domestic supply is 20 ppm 
  • for the public supply colour number on cobalt scale not exceed 20  and not lessthan 10 
3. Taste and Odour

  • the dissolved orgenic matter and dissolved gasesimpart the taste and odour of the water
  • dissolved gases such as H2S,CO2,O2,CH4...etc
  • for the drinking purpose the water must not containany objectionable taste and odour
  • for the public supply the water should be free from odour  and odour  number should be 1 and not exceed 3

4. Temprature

  • for the potable water 10 degree celcius temprature highly desirable
  • Temprature above 25 degree celcius concidered objectionable
5.specific conductivity

  • specific conductivity of the water is the ability of water to conduct electricity
  • pure water is poor conductor of electricity
  • The specific conductivity is measured by potable ionic water tester called conductivity sensor
  • onductivity is measured in (mhos)
  • mhos = 1amp/1valt
  • or 1mhos = 1seimen this unit is renamed by ISO
  •  In clean water it range is (micro seimen/cm = 1*10^-6 seimen/cm)
  • specific conductivity of water is increased with the increasing temprature so it's measured at 25 degree celcius (standatd temprature )
  • to convert micro (seimen./cm) into ppm we will have to multiply by conductiity facotor
  • conductivity factor vary from 0.54 to 0.96 and generrally it's taken 0.67 

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