Suspended solids refers to small solid particles which remain in
suspensionIn chemistry, a suspension is a heterogeneous fluid containing solid particles that are sufficiently large for sedimentation. Usually they must be larger than 1 micrometer. The internal phase is dispersed throughout the external phase through mechanical agitation, with the use of certain...
in water as a
colloidA colloid is a substance microscopically dispersed evenly throughout another substance.A colloidal system consists of two separate phases: a dispersed phase and a continuous phase . A colloidal system may be solid, liquid, or gaseous.Many familiar substances are colloids, as shown in the chart below...
or due to the motion of the water. It is used as one indicator of
water qualityWater quality is the physical, chemical and biological characteristics of water. It is a measure of the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose. It is most frequently used by reference to a set of standards against which...
.
It is sometimes abbreviated
SS, but is not to be confused with
settleable solidsSettling is the process by which particulates settle to the bottom of a liquid and form a sediment. Particles that experience a force, either due to gravity or due to centrifugal motion will tend to move in a uniform manner in the direction exerted by that force...
, also abbreviated SS, which contribute to the blocking of
sewerA sanitary sewer is a separate underground carriage system specifically for transporting sewage from houses and commercial buildings to treatment or disposal. Sanitary sewers serving industrial areas also carry industrial wastewater...
pipes.
Explanation
Suspended solids are important as
pollutantA pollutant is a waste material that pollutes air, water or soil, and is the cause of pollution.Three factors determine the severity of a pollutant: its chemical nature, its concentration and its persistence. Some pollutants are biodegradable and therefore will not persist in the environment in the...
s and
pathogenA pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
s are carried on the surface of particles. The smaller the particle size, the greater the total surface area per unit mass of particle, 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
sedimentationSedimentation is a physical water treatment process used to settle out suspended solids in water under the influence of gravity.-Basics:Suspended solids , is the mass of dry solids retained by a filter of a given porosity related to the volume of the water sample...
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 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 filterDeveloped for use in Bangladesh, the cloth filter is a simple and cost-effective appropriate technology method for reducing the contamination of drinking water...
, consisting of a folded cotton
sariA sari or sareeThe name of the garment in various regional languages include: , , , , , , , , , , , , , is a strip of unstitched cloth, worn by females, ranging from four to nine metres in length that is draped over the body in various styles. It is popular in India, Bangladesh, Nepal,...
, drastically reduces the load of
choleraCholera is an infection of the small intestine that is caused by the bacterium Vibrio cholerae. The main symptoms are profuse watery diarrhea and vomiting. Transmission occurs primarily by drinking or eating water or food that has been contaminated by the diarrhea of an infected person or the feces...
carried in the water, and is suitable for use by the very poor; in this case, an
appropriate technologyAppropriate technology is an ideological movement originally articulated as "intermediate technology" by the economist Dr...
method of disinfection might be added, such as
solar water disinfectionSolar water disinfection, also known as SODIS is a method of disinfecting water using only sunlight and plastic PET bottles. SODIS is a free and effective method for decentralized water treatment, usually applied at the household level and is recommended by the World Health Organization as a viable...
.
A major exception to this generalization is
arsenic contamination of groundwaterArsenic contamination of groundwater is a natural occurring high concentration of arsenic in deeper levels of groundwater, which became a high-profile problem in recent years due to the use of deep tubewells for water supply in the Ganges Delta, causing serious arsenic poisoning to large numbers of...
, as
arsenicArsenic is a chemical element with the symbol As, atomic number 33 and relative atomic mass 74.92. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. It was first documented by Albertus Magnus in 1250.Arsenic is a metalloid...
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
- Total suspended solids
Total suspended solids is a water quality measurement usually abbreviated TSS. It is listed as a conventional pollutant in the U.S. Clean Water Act. This parameter was at one time called non-filterable residue , a term that refers to the identical measurement: the dry-weight of particles trapped...
- Turbidity
Turbidity is the cloudiness or haziness of a fluid caused by individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality....
- Bottom trawling
Bottom trawling is trawling along the sea floor. It is also often referred to as "dragging".The scientific community divides bottom trawling into benthic trawling and demersal trawling...