Science popularization | Water quality index: turbidity, suspended solids detection TSS ≠ turbidity

2022-08-19 16:17


Turbidity: refers to the degree of obstruction caused by solution to light passing through, also called turbidity. Turbidity is caused by suspended substances such as sediment, clay, organic matter, inorganic matter, plankton and microorganism in water, which can scatter or absorb light. Although turbidity and chromaticity are both optical properties of water, they are different. Chromaticity is caused by dissolved substances in water, while turbidity is caused by insoluble substances in water.


Measurement significance of turbidity and suspended solids:

● Characterize the clarity of water

● Characterize the concentration of suspended solids in water

● One of the important evaluation indicators of water quality

Although some sediments will settle at the bottom of the water source, other TSS will float on the water surface or suspend between them. TSS will affect the transparency of water, so the higher the TSS content of water source, the worse the transparency.



What are the common suspended solids?




Bacteria are most commonly found in well water sources. Legionella and coliform bacteria are common types of aquatic bacteria. Certain types of bacteria pose a risk when eaten.



Similarly, clay is a common well water pollutant, especially colloidal clay. This type of TSS may give the water a particularly cloudy appearance. Although a small amount of clay may not be harmful to health, it may affect the taste and smell of water and is known to be difficult to remove.



In areas with sandy soil composition, sand in water is particularly problematic. Similarly, if they are well owners, this is a problem that is most likely to be encountered. The simplest solution is to filter it with a sediment filter. Sand is another heavy particle, usually deposited at the bottom of a water body.



Finally, the size of silt particles is usually between sand and clay and can be found in rivers, lakes and soil. Although silt is not usually dangerous, it may damage the appearance of the water and may affect the appearance of the water.


What is the effect of high TSS in water?


High total suspended solids in drinking water or wastewater can have an impact on the environment and human health.

How to distinguish TSS from turbidity?


Turbidity and suspended solids are often used interchangeably, making it difficult to understand the difference between them. However, they are not identical.

Limits of turbidity and suspended solids:

The turbidity of drinking water and suspended solids of sewage are detected.

■ According to GB5749-2006 Sanitary Standard for Drinking Water, the turbidity is less than 1NTU.

■ Suspended solids are discharged according to the requirements of GB8978-1996 Integrated Wastewater Discharge Standard. Sewage treatment plant: Grade I 20mg/L, Grade II 30mg/L; Beneficiation: Grade I 70mg/L, Grade II above 300mg/L; Other sewage discharge: 70mg/L for Grade I, 150mg/L for Grade II and 400mg/L for Grade III.