Point-of-Use (POU) water treatment
Encyclopedia
Point-of-use water treatment refers to a variety of different water treatment
methods (physical, chemical and biological) used to improve water quality
for an intended use (drinking, bathing, washing, irrigation, etc), at the point of consumption instead of at a centralized scale (involving a distribution network). POU treatment encompasses water treatment at a more decentralized scale like in a small community or at the household level; furthermore, safely storing water (especially unclean water) is a huge challenge, therefore upon water use, a POU treatment method (below) can be applied to improve the water quality .
A multi-barrier approach utilizing more than one of these methods is often recommended to maximize the effectiveness in inactivating pathogen
s that cause diarrheal diseases, removing particulates
and/or contaminants that are naturally toxic or inhibit the effectiveness of the desired water treatment
method .
often becomes a challenge and requires alternatives to the conventional water treatment system consisting of coagulation
, flocculation
, sedimentation
, filtration
and disinfection (most commonly chlorination
).
This conventional system alone demands large amounts of capital investment and complex water management infrastructure
that would often not be feasible in decentralized, poor, underdeveloped regions. In this case, point of use treatment systems, technologies and methods allow underdeveloped regions to utilize simpler, more cost effective means of water purification
.
and aid in ensuring potable water or safeguarding against particular contaminants of concern. As water leaves the water treatment plant, water most often meets or exceeds standards regulated by the local governing authority (EPA in the US); however due to a large amount of aging infrastructure (dating back to the 1920s for public utilities in the US and before depending on the age of the home) water quality has the potential to degrade leaving people to find aesthetically unpleasing and sometimes unsafe drinking water at the tap within the household.
at the home like the following:
, people are often advised to add iodine
, chlorine tablets or one of a series of other products to cleanse the local surface water
before consuming it. This practice has been used for years and is highly recommended to ensure the water is bacteriologically suitable, or as suitable as possible to be consumed. Historically speaking, iodine tablets were used but with newer technologies and products, chlorine tablets have become less expensive and seem to be the preferred treatment.
Water treatment
Water treatment describes those processes used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment process is to remove existing contaminants in the water, or reduce the...
methods (physical, chemical and biological) used to improve water quality
Water quality
Water 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...
for an intended use (drinking, bathing, washing, irrigation, etc), at the point of consumption instead of at a centralized scale (involving a distribution network). POU treatment encompasses water treatment at a more decentralized scale like in a small community or at the household level; furthermore, safely storing water (especially unclean water) is a huge challenge, therefore upon water use, a POU treatment method (below) can be applied to improve the water quality .
Methods
POU treatment methods include one or a combination of the following treatment methods:- boiling
- ceramic pot filtration
- chlorinationChlorinationChlorination is the process of adding the element chlorine to water as a method of water purification to make it fit for human consumption as drinking water...
- cloth filtration
- natural or chemical coagulationCoagulationCoagulation is a complex process by which blood forms clots. It is an important part of hemostasis, the cessation of blood loss from a damaged vessel, wherein a damaged blood vessel wall is covered by a platelet and fibrin-containing clot to stop bleeding and begin repair of the damaged vessel...
- pasteurizationPasteurizationPasteurization is a process of heating a food, usually liquid, to a specific temperature for a definite length of time, and then cooling it immediately. This process slows microbial growth in food...
- sand filtration
- solar disinfection (SODIS)
A multi-barrier approach utilizing more than one of these methods is often recommended to maximize the effectiveness in inactivating pathogen
Pathogen
A 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 that cause diarrheal diseases, removing particulates
Particulates
Particulates – also known as particulate matter , suspended particulate matter , fine particles, and soot – are tiny subdivisions of solid matter suspended in a gas or liquid. In contrast, aerosol refers to particles and/or liquid droplets and the gas together. Sources of particulate matter can be...
and/or contaminants that are naturally toxic or inhibit the effectiveness of the desired water treatment
Water treatment
Water treatment describes those processes used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment process is to remove existing contaminants in the water, or reduce the...
method .
Underdeveloped regions
In underdeveloped regions (underdeveloped nations), water treatmentWater treatment
Water treatment describes those processes used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment process is to remove existing contaminants in the water, or reduce the...
often becomes a challenge and requires alternatives to the conventional water treatment system consisting of coagulation
Coagulation
Coagulation is a complex process by which blood forms clots. It is an important part of hemostasis, the cessation of blood loss from a damaged vessel, wherein a damaged blood vessel wall is covered by a platelet and fibrin-containing clot to stop bleeding and begin repair of the damaged vessel...
, flocculation
Flocculation
Flocculation, in the field of chemistry, is a process wherein colloids come out of suspension in the form of floc or flakes by the addition of a clarifying agent. The action differs from precipitation in that, prior to flocculation, colloids are merely suspended in a liquid and not actually...
, sedimentation
Sedimentation
Sedimentation is the tendency for particles in suspension to settle out of the fluid in which they are entrained, and come to rest against a barrier. This is due to their motion through the fluid in response to the forces acting on them: these forces can be due to gravity, centrifugal acceleration...
, filtration
Filtration
Filtration is commonly the mechanical or physical operation which is used for the separation of solids from fluids by interposing a medium through which only the fluid can pass...
and disinfection (most commonly chlorination
Chlorination
Chlorination is the process of adding the element chlorine to water as a method of water purification to make it fit for human consumption as drinking water...
).
This conventional system alone demands large amounts of capital investment and complex water management infrastructure
Water treatment
Water treatment describes those processes used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment process is to remove existing contaminants in the water, or reduce the...
that would often not be feasible in decentralized, poor, underdeveloped regions. In this case, point of use treatment systems, technologies and methods allow underdeveloped regions to utilize simpler, more cost effective means of water purification
Water purification
Water purification is the process of removing undesirable chemicals, materials, and biological contaminants from contaminated water. The goal is to produce water fit for a specific purpose...
.
Example
Communal taps are sometimes found in underdeveloped regions (underdeveloped nations) whereby community members can collect water from a somewhat centralized location (tap, faucet, pump) and treat the water with any of the previously mentioned POU methods. If communal taps are not an option, people typically make daily trips to the nearby water source (river, lake, etc. which can sometimes be miles away), collect water in large jars/containers and transport it home to be treated with one of the previously mentioned POU methods.Developed regions
In developed regions (developed nations), POU treatment methods are found to supplement water treatmentWater treatment
Water treatment describes those processes used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment process is to remove existing contaminants in the water, or reduce the...
and aid in ensuring potable water or safeguarding against particular contaminants of concern. As water leaves the water treatment plant, water most often meets or exceeds standards regulated by the local governing authority (EPA in the US); however due to a large amount of aging infrastructure (dating back to the 1920s for public utilities in the US and before depending on the age of the home) water quality has the potential to degrade leaving people to find aesthetically unpleasing and sometimes unsafe drinking water at the tap within the household.
Example
Because of aging infrastructure many products have been developed to aid in water treatmentWater treatment
Water treatment describes those processes used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment process is to remove existing contaminants in the water, or reduce the...
at the home like the following:
- reverse osmosis filters in refrigerators
- filtering pitcher systems (Brita, Berkey, Berkey Water Filter etc.)
- filtering tap nozzles (Brita, Pur, etc.)
- Gadyen Dlo, sponsored by Deep Springs InternationalDeep Springs InternationalDeep Springs International is a US nonprofit corporation, headquartered in Léogâne, Haiti, which supports the establishment and expansion of Gadyen Dlo social enterprises...
Recreational application
While campingCamping
Camping is an outdoor recreational activity. The participants leave urban areas, their home region, or civilization and enjoy nature while spending one or several nights outdoors, usually at a campsite. Camping may involve the use of a tent, caravan, motorhome, cabin, a primitive structure, or no...
, people are often advised to add iodine
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....
, chlorine tablets or one of a series of other products to cleanse the local surface water
Surface water
Surface water is water collecting on the ground or in a stream, river, lake, wetland, or ocean; it is related to water collecting as groundwater or atmospheric water....
before consuming it. This practice has been used for years and is highly recommended to ensure the water is bacteriologically suitable, or as suitable as possible to be consumed. Historically speaking, iodine tablets were used but with newer technologies and products, chlorine tablets have become less expensive and seem to be the preferred treatment.
See also
- Drinking waterDrinking waterDrinking water or potable water is water pure enough to be consumed or used with low risk of immediate or long term harm. In most developed countries, the water supplied to households, commerce and industry is all of drinking water standard, even though only a very small proportion is actually...
- Water pasteurization indicatorWater Pasteurization IndicatorA water pasteurization indicator is a simple thermometer that indicates when water has reached pasteurization temperature and is safe to drink. It was invented by Fred Barrett and Dale Andreatta....
: Describes a simple "go-no go" thermometer for POU pasteurization. - Safe Household Water StorageSafe Household Water StorageSafe household water storage is a critical component of a Household Water Treatment and Safe Storage system being promoted by the World Health Organization worldwide in areas that do not have piped drinking water. In these areas it is not uncommon for drinking water to be stored in a pot, jar,...