Total Suspended solids

This is the amount of fine particulate matter in suspension in water of size greater than two microns.  It is measured by weight per volume of sample and usually quoted as mg/l.

It is similar to turbidity but provides an actual weight of particulate matter rather than a perception. TSS can encompass both organic particulate such as plankton and algae, in addition to inorganic matter such as sand and silts.

In the lab TSS can be measured by dehydrating a water sample and weighed the precipitate. In the field it is possible to measure a TSS using infra-red radiation or microwave radiation.

Why does TSS matter?

Regulated in discharge

Solids give nucleation sites for bacterial colonies

Particles can clog filters and damage pumps

Interferes with coagulation, filtration, and disinfection processes

How do you measure TSS?

The Total suspended solids (TSS) can be measured by using an infrared(IR) light through any liquid and the TSS value will increase linearly with IR absorption. 

Photonic measurements devices are able to measure TSS in the range of 8mg/l up to 50,000mg/l

Using Beer lamberts law:

ABS = ε ϲ І

The concentration of suspended solids is equal to

ϲ = ABS /  (ε  І)  

where the terms are:
The Infrared absorption value (ABS) 
The length 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 .


Lisburn, BT28 2GN, GB

About us

Photonic Measurements is:
Incorporated in N.Ireland (NI622996) 
VAT registered in UK (GB192
VAT registered in N.Ireland (XI192976846000)

Follow us