Suspended solids refers to small solid particles which remain in
suspension in water as a
colloid or due to motion of the water. Suspended solids can be removed by
sedimentation if their size or density is comparatively large, or by
filtration.
It is used as one indicator of
water quality and of the strength of
sewage, or
wastewater in general. It is an important design parameter for
sewage treatment processes.
It is sometimes abbreviated SS, but is not to be confused with
settleable solids, also abbreviated SS, which contribute to the blocking of
sewer pipes.
Explanation
Suspended solids are important as
pollutants and
pathogen
In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a Germ theory of d ...
s are carried on the surface of particles. The smaller the particle size, the greater the total surface area per unit mass of particle in grams, and so the higher the
pollutant load that is likely to be carried.
Removal
Removal of suspended solids is generally achieved through the use of
sedimentation and/or
water filters (usually at a municipal level). By eliminating most of the suspended solids in a water supply, the significant water is usually rendered close to drinking quality. This is followed by
disinfection
A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than ...
to ensure that any free floating pathogens, or pathogens associated with the small remaining amount of suspended solids, are rendered ineffective.
Effectiveness of filtering
The use of a very simple
cloth filter, consisting of a folded cotton
sari, drastically reduces the load of
cholera
Cholera () is an infection of the small intestine by some Strain (biology), strains of the Bacteria, bacterium ''Vibrio cholerae''. Symptoms may range from none, to mild, to severe. The classic symptom is large amounts of watery diarrhea last ...
carried in the water, and is suitable for use by the very poor; in this case, an
appropriate technology
Appropriate technology is a movement (and its manifestations) encompassing technology, technological choice and application that is small-scale, affordable by its users, labor-intensive, efficient energy use, energy-efficient, environmentally sust ...
method of disinfection might be added, such as
solar water disinfection.
A major exception to this generalization is
arsenic contamination of groundwater, as
arsenic is a very serious pollutant which is soluble, and thus not removed when suspended solids are removed. This makes it very difficult to remove, and finding an alternative water source is often the most realistic option.
See also
*
Bottom trawling
*
Total suspended solids
*
Turbidity
References
Water
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