The Differences Between Turbidity and Suspended Solids Measurements in Water Quality Sensing

Turbidity and suspended solids can be used to measure water quality. In this article, we will explore the differences between turbidity and suspended solids measurements.

What is Turbidity?

Turbidity is a measurement of the cloudiness or haziness of a liquid caused by suspended particles that scatter or absorb light. These particles can be inorganic or organic matter, algae, or microbial cells. Turbidity is usually measured in Nephelometric Turbidity Units (NTU) or FNU using a turbidimeter.

Turbidity measurements are critical in water quality monitoring and control. High turbidity levels can reduce light penetration, affect aquatic plant and animal survival, and cause problems with drinking water treatment. Turbidity can also impact recreational water activities, such as swimming and boating.

What is Suspended Solids?

Suspended solids are particles in water that may be seen or unseen to the naked eye and do not dissolve in water. They can be made up of organic and inorganic matter, such as sand, silt, and clay, as well as living and dead microorganisms. Suspended solids can be measured in milligrams per liter (mg/L) or parts per million (ppm).

The presence of suspended solids in water can cause environmental and health problems. They can clog water intakes and harm aquatic organisms' health and reproduction. Suspended solids can also interfere with water treatment, such as settling and filtration, and lead to increased operational costs.

Differences Between Turbidity and Suspended Solids

Turbidity and suspended solids may appear to be similar measurements, but there are significant differences in how they are measured and the types of particles they measure.

1. Measurement Technique

Turbidity is measured using a turbidimeter that sends light through a water sample, and the amount of scattered or absorbed light is measured. Suspended solids can be measured using filtration techniques, such as a gravimetric filter or a continuous measurement technique called a turbidity probe.

2. Particles Measured

Turbidity measures the total amount of all suspended particles that affect light transmission in water. On the other hand, suspended solids only measure the solid particulates, not the dissolved minerals or gases.

3. Quantitative vs. Qualitative Measurements

Turbidity measurements are quantitative and provide numerical values indicating the degree of cloudiness in the water. In contrast, suspended solids measurements are qualitative and can only determine the presence or absence of solid particles.

4. Units of Measurement

Turbidity is measured in NTU or FNU, while suspended solids are measured in mg/L or ppm.

5. Applicability

Turbidity is useful for detecting changes in water quality caused by changes in suspended solids concentration, such as increased nutrient loading, algal blooms, or stormwater runoff. Suspended solids measurements are useful for specific applications, such as wastewater treatment, erosion control, and sediment transport.

Conclusion

In conclusion, both turbidity and suspended solids are valuable measurements for monitoring and controlling water quality. Turbidity measures the total amount of all suspended particles affecting light transmission in water, while suspended solids only measure the solid particulates present. Turbidity measurements are quantitative, while suspended solids measurements are qualitative. While both measurements have their advantages and disadvantages, they are essential in maintaining environmental health and public safety.