Turbidity: It is the measure of inter frame given by insoluble process of soil organics, mionoorganisms and other materials for the passage of light through water the standard unit is

that which is produced by 1 milligram of finely divided silico in one litre of distilled water the permissible limit of turbidity is 5 to 10units on silica scale.

The turbidity may be measured in the laboratory by following instruments

i.                   Turbidity Rod

ii.                 Jackson?s Turbidity meter

iii.              Nephelo Turbidity meter

iv.              Baylis Turbidity meter

v.                 Hellige Turbidity meter

JACKSON’S TURBIDITY METER

 It is the std. instrument for measuring turbidity. It essentially consists of a calibrated glass tube, a metallic container tube (or holder), a standard candle and a metallic stand. The glass tube is placed in the container and the candle or standard source of light is placed below the container. The water sample B poured slowly in the glass tube until the outline of the candle flume is no longer visible. Readings in terms of Jackson turbidity unit (JTU) are then taken directly from the calibrated tube.

TASTE AND ODOUR

 The dissolved organic materials and inorganic salts or dissolved gases impart taste and odors to the water but for the drinking water it must not contain any undesirable or objectionable taste and odors. It is measured in terms of odors intensity which is related with the threshold number. The Threshold number represents the dilution ration at which the odors is hardly detectable. For domestic purpose the threshold odors umber is limited between 1 and 3