What are Total Suspended Solids?
In stormwater runoff, Total Suspended Solids (TSS) refers to undissolved solid particles larger than 0.45µm. Anything smaller is considered a dissolved substance. Pollutants can bind to or become trapped within these solid particles, making TSS a highly effective contaminant transport mechanism from surface road runoff into receiving water bodies.
Infographhic: Sources of Total Suspended Solids (TSS) in road run off and contaminants that bind to them.
In road runoff, TSS includes a mixture of natural and synthetic contaminants, such as:
- Tyre wear particles
- Brake pad dust
- Road paint particles
- Asphalt particles
- Fuel and lubricant losses
- De-icing residues
- Litter and microplastics
- Soil or waste stuck to tyres
TSS particles have large surface areas, meaning they provide strong adsorptive properties that can readily bind contaminants such as heavy metals, hydrocarbons (PAHs), oils, nutrients from organic matter, and microorganisms like pathogens and bacteria.
Why does contaminated TSS matters?
While TSS itself is a pollutant, the contaminants they ‘carry’ are of more concern. When contaminated TSS enters receiving water bodies such as lakes, rivers and oceans via stormwater drainage, harmful effects on aquatic organisms and the aquatic environment may occur. Soils too can accumulate such pollution.
- Rise in toxicity levels
The attached pollutants can accumulate in both sediments and organisms in aquatic environments. This bioaccumulation of toxic chemicals can affect the development, growth and reproduction of living aquatic organisms while degrading the overall ecosystem’s health. - Reduced water clarity
The increase in a water body’s turbidity can make the water appear as cloudy. This prevents photosynthesis from taking place in plants and algae, lowering oxygen levels and affecting the survival of aquatic life, possibly destroying the entirety of the aquatic food web. - Sedimentation and habitat alteration
The accumulation of particles at the bottom of water bodies through the process of sedimentation can literally clog habitats and alter topography at the bed of the water. - Impact on stormwater treatment systems
High loads of TSS can clog sediment basins, filters, pipes and other stormwater treatment devices. Overall efficiency of the treatment device to remove unwanted contaminants will decrease, meaning more frequent maintenance is required. - Human impacts
Contaminated water bodies may alter the required water treatment methods to meet safe drinking water guidelines. Recreational water bodies such as lakes could become toxic and generate health consequences for humans.
Mitigation practices
The 3P Technik HydroSystem is a multi-process stormwater treatment device. The four treatment stages of sedimentation, filtration, adsorption and ion exchange ensure the output of clean, safe water. This multi process system is specifically designed for use in high trafficked areas, where TSS particles are assumed to be high, and with high concentrations of contaminants attached to them. With the removal of these toxic TSS particles, the potential harmful effects to aquatic life, environments and human health will be significantly reduced. The typical UK Mitigation Index for these filters is 0.8, 0.9, 0.9.
Author: Alys Bradshaw, 3P Technik UK Ltd.
Treatment Solutions for TSS in Stormwater and Road Runoff
Our industry-leading treatment systems are specifically engineered to provide proven, reliable TSS removal in stormwater applications, ensuring performance you can trust both now and into the future.
3P Technik’s technical team can provide project-specific advice and support. Please contact us to discuss your requirements.
References
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- Hills, M. 2016. All stormwater particles are not the same. Part 1: particle size and composition. https://www.conteches.com/knowledge-center/learn/the-stormwater-blog/all-stormwater-particles-are-not-the-same-part-1-particle-size-and-composition/
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- Ogbonna, C., Emmanuel, A., Nwachi, C. and Okeoma, I. 2023. Total suspended solids loading of stormwater from different land use areas in an urban watershed. https://www.researchgate.net/publication/377276939_Total_suspended_solids_loading_of_stormwater_from_different_land_use_areas_in_an_urban_watershed
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