To determine the Turbidity contents of given sample of water
Discussion:
Turbidity occurs most surface waters as the result of suspended clay, sill, finely divided organic and inorganic matter, plankton and other microorganisms. The turbidity test measures an optical property of the water sample, which results from the scattering, and absorbing of light by the particular matter present. The amount of turbidity measured depends on such variables as size, shape and refractive index of the particles. No direct relationship exists between the turbidity of a water sample and the weight concentration of the matter present, as it is determined in the suspended solids test
High levels of turbidity can protect microorganisms from the effects of disinfection and can stimulate the growth of bacteria. In all cases where water is disinfected, therefore, the turbidity must be low preferably below I NTU) so that disinfection can be effective.
The guideline value is 5 nephelometric turbidity units (NTU) or 5 Jackson turbidity units (JTU), but preferably less than 1 NTU when disinfection is practiced. Turbidity in excess of (5 NTU)/ (5 JTU) may be noticeable and consequently, objectionable to consumers.
Plain Test Method
Using the Standard Tube Equivalent to JTU (Jackson Turbidity Unit)
Apparatus
Jackson Turbidity Unit
Beakers
Water Samples
Procedure
- Hold the tube vertically over a white surface and view downwards.
- Gradually pour in the effluent/sample until the black cross is just no longer visible.
- Read off the graduation corresponding to the height of the sample in the tube. This represents the turbidity of the sample in Jackson Turbidity Units (JTU). For the effluents the educations may to be taken as being approximately equivalent to the Suspended Solids Content as milligrams per liter
Summary of Method
The turbidity test measures an optical property of the water sample, which results from the scattering and absorbing of light by the particulate matter present. The amount of turbidity measured depends on such variables as size, shape and refractive index of the particles.