Turbidity is a measure of the degree to which the water loses its transparency due to the presence of suspended particulates.
The more total suspended solids in the water, the murkier it seems and the higher the turbidity.
Turbidity is considered as a good measure of the quality of water.
There are various parameters influencing the cloudiness of the water. Some of these are:
- Sediments from erosion
- Resuspended sediments from the bottom (frequently stir up by bottom feeders like carp)
- Waste discharge
- Algae growth
- Urban runoff
The WHO (World Health Organization), establishes that the turbidity of drinking water shouldn't be more than 5 NTU, and should ideally be below 1 NTU.
The suspended particles absorb heat from the sunlight, making turbid waters become warmer, and so reducing the concentration of oxygen in the water (oxygen dissolves better in colder water). Some organisms also can’t survive in warmer water.
The suspended particles scatter the light, thus decreasing the photosynthetic activity of plants and algae, which contributes to lowering the oxygen concentration even more.
As a consequence of the particles settling to the bottom, shallow lakes fill in faster, fish eggs and insect larvae are covered and suffocated, gill structures get clogged or damaged…
The main impact is merely esthetic: nobody likes the look of dirty water.
But also, it is essential to eliminate the turbidity of water in order to effectively disinfect it for drinking purposes. This adds some extra cost to the treatment of surface water supplies.
The suspended particles also help the attachment of heavy metals and many other toxic organic compounds and pesticides.
Turbidity is measured in NTU: Nephelometric Turbidity Units. The instrument used for measuring it is called nephelometer or turbidimeter, which measures the intensity of light scattered at 90 degrees as a beam of light passes through a water sample.
The unit used in the ancient times was JTU (Jackson Turbidity Units), measured with the Jackson candle turbidimeter. This unit is no longer in standard use.
A turbidity measurement could be used to provide an estimation of the TSS (Total Suspended Solids) concentration, which is otherwise a tedious and difficult parameter to measure.
Lenntech can provide you with a turbidimeter to measure the turbidity of your water. Please do not hesitate to contact us if you want any information on this.