What it is
Total suspended solids (TSS) is the dry weight of material caught on a fine filter from a known volume of sample. It includes everything from grit and fibres to food particles, fats and biological floc. Alongside BOD or COD, it is one of the two figures almost every trade effluent consent and charging formula is built on.
Where it comes from
Product losses and wash-down are the usual source: vegetable matter, flour, meat and fish particles, paper and textile fibres, soil from root crops, grit from yards, and sludge disturbed from drains. Poorly maintained interceptors and settlement tanks release solids in slugs when they are overloaded or stirred up.
Why it matters
Suspended solids silt up sewers and pumping stations, smother river beds, and carry other pollutants with them. In the consent they usually have their own limit and their own charge component. Fine, slow-settling solids are harder to remove and are the ones that typically cause a breach.
What can be done about it
Keep solids out of the drain with screens, drain baskets and dry clean-up before washing down. Then give them somewhere to settle: an interceptor, settlement tank or balancing tank sized for your flow, emptied on a schedule. Where fine solids remain, flocculation or dissolved-air flotation removes them. A Pozzani engineer can size and specify this for your site.
Information last reviewed 6 October 2026 by Pozzani Pure Water.