Total Suspended Solids

Total Suspended Solids (TSS)

Total Suspended Solids (TSS) refers to the quantity of fine particulate matter suspended in water, with a size greater than two microns. It is typically measured in milligrams per liter (mg/l) and serves as a crucial parameter in water quality assessment.

Understanding TSS

TSS serves as a quantifiable indicator of the amount of suspended solids in water, offering a similar, yet unique, measurement to be compared with turbidity. These suspended solids can vary widely in composition, encompassing organic particulates like plankton and algae, as well as inorganic matter such as sand, silts and particle run-off

Importance of TSS

TSS holds significant importance for various reasons, including water process efficiency, regulatory compliance, infrastructure and asset maintenance control. TSS levels are often regulated in water discharge, ensuring environmental standards are met. Excessive TSS can lead to clogging of filters and damage to pumps and other water assets, this commonly leads to costly repairs and maintenance. A high level of TSS can interfere with water treatment processes like coagulation, filtration and disinfection, affecting their effectiveness. A high level of suspended solids provide nucleation sites for bacterial colonies, impacting overall water quality and ecosystem health. TSS can be a useful early indicator of issues with water quality.

Measuring TSS

Various TSS measurement techniques exist and are applied in labs and in the field. The laboratory method involves dehydrating a water sample and measuring the weight of the precipitate, providing accurate TSS values. Or a probe is used with a scientific controller such as the universal controller.

TSS can be measured in real-time and onsite using a TSS/MLSS infrared (IR) probe. Photonic Measurement devices, use this method of IR absorption to quantify TSS levels, offering a range from 5 mg/L to 50,000 mg/L depending on pathlength.

Using Beer lamberts law:

ABS = ε ϲ І


The concentration of suspended solids is equal to

ϲ = ABS / (ε І)

where the terms are:
ABS= The Infrared absorption value (ABS)
The pathlength of the probe (L)
The calibration factor (ε)

The path length can be specified at the time of ordering a TSS probe. The choice will be based on the expected values expected whether in the anoxic tank or final discharge .