Water quality

qualitywaterhydrochemistrychemical hydrologyquality of waterdrinking water pollutiondrinking water qualityhydrochemistlake waterwater quality report
Water quality refers to the chemical, physical, biological, and radiological characteristics of water.wikipedia
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Water treatment

water treatment planttreatmenttreatment plant
It is most frequently used by reference to a set of standards against which compliance, generally achieved through treatment of the water, can be assessed.
Water treatment is any process that improves the quality of water to make it more acceptable for a specific end-use.

Drinking water

potable waterpotableclean water
The most common standards used to assess water quality relate to health of ecosystems, safety of human contact, and drinking water.
Typically in developed countries, tap water meets drinking water quality standards, even though only a small proportion is actually consumed or used in food preparation.

Pollution

pollutedenvironmental pollutionpollution control
Another general perception of water quality is that of a simple property that tells whether water is polluted or not.
London also recorded one of the earlier extreme cases of water quality problems with the Great Stink on the Thames of 1858, which led to construction of the London sewerage system soon afterward.

Safe Drinking Water Act

Safe Drinking WaterUnderground Injection Control Program Safe Drinking Water Act (SDWA)
The Safe Drinking Water Act authorizes EPA to issue two types of standards:
Pursuant to the act, the Environmental Protection Agency (EPA) is required to set standards for drinking water quality and oversee all states, localities, and water suppliers that implement the standards.

Water purification

purificationwater purifierpurified
In urbanized areas around the world, water purification technology is used in municipal water systems to remove contaminants from the source water (surface water or groundwater) before it is distributed to homes, businesses, schools and other recipients.
The standards for drinking water quality are typically set by governments or by international standards.

Tap water

running waterindoor plumbingmunicipal water
The United States Environmental Protection Agency (EPA) limits the amounts of certain contaminants in tap water provided by US public water systems.
Usually it is potable, although water quality problems are not rare.

Water

H 2 Oliquid wateraqueous
Water quality refers to the chemical, physical, biological, and radiological characteristics of water.
Poor water quality and bad sanitation are deadly; some five million deaths a year are caused by polluted drinking water.

Surface runoff

runoffagricultural runoffrun-off
Industrial and commercial activities (e.g. manufacturing, mining, construction, transport) are a major cause of water pollution as are runoff from agricultural areas, urban runoff and discharge of treated and untreated sewage.
A 2008 report by the United States National Research Council identified urban stormwater as a leading source of water quality problems in the U.S.

Water pollution

pollutionpollutedwater
Industrial and commercial activities (e.g. manufacturing, mining, construction, transport) are a major cause of water pollution as are runoff from agricultural areas, urban runoff and discharge of treated and untreated sewage.
In the United States, best management practices for water pollution include approaches to reduce the quantity of water and improve water quality.

Turbidity

turbidNephelometric Turbidity UnitsNTU
Measurements commonly made on-site and in direct contact with the water source in question include temperature, pH, dissolved oxygen, conductivity, oxygen reduction potential (ORP), turbidity, and Secchi disk depth. The key basic water quality parameters that need to be addressed in an emergency are bacteriological indicators of fecal contamination, free chlorine residual, pH, turbidity and possibly conductivity/total dissolved solids.
The measurement of turbidity is a key test of water quality.

Soil

dirtsoilssoil moisture
The first problem is the extent to which the sample may be representative of the water source of interest. Many water sources vary with time and with location. The measurement of interest may vary seasonally or from day to night or in response to some activity of man or natural populations of aquatic plants and animals. The measurement of interest may vary with distances from the water boundary with overlying atmosphere and underlying or confining soil. The sampler must determine if a single time and location meets the needs of the investigation, or if the water use of interest can be satisfactorily assessed by averaged values with time and location, or if critical maxima and minima require individual measurements over a range of times, locations or events. The sample collection procedure must assure correct weighting of individual sampling times and locations where averaging is appropriate. Where critical maximum or minimum values exist, statistical methods must be applied to observed variation to determine an adequate number of samples to assess probability of exceeding those critical values.
Soil acts as an engineering medium, a habitat for soil organisms, a recycling system for nutrients and organic wastes, a regulator of water quality, a modifier of atmospheric composition, and a medium for plant growth, making it a critically important provider of ecosystem services.

Ion

cationanionions
The most familiar of these is probably the presence of ions of calcium (Ca 2+ ) and magnesium (Mg 2+ ) which interfere with the cleaning action of soap, and can form hard sulfate and soft carbonate deposits in water heaters or boilers.
Inorganic dissolved ions are a component of total dissolved solids, a widely-known indicator of water quality.

Urban runoff

runoffstormwater runoffletting it flow into the sewers
Industrial and commercial activities (e.g. manufacturing, mining, construction, transport) are a major cause of water pollution as are runoff from agricultural areas, urban runoff and discharge of treated and untreated sewage.
A 2008 report by the United States National Research Council (textbox below) identified urban runoff as a leading source of water quality problems.

Suspended solids

suspended solidparticulate matterparticulates
The second problem occurs as the sample is removed from the water source and begins to establish chemical equilibrium with its new surroundings – the sample container. Sample containers must be made of materials with minimal reactivity with substances to be measured; and pre-cleaning of sample containers is important. The water sample may dissolve part of the sample container and any residue on that container, or chemicals dissolved in the water sample may sorb onto the sample container and remain there when the water is poured out for analysis. Similar physical and chemical interactions may take place with any pumps, piping, or intermediate devices used to transfer the water sample into the sample container. Water collected from depths below the surface will normally be held at the reduced pressure of the atmosphere; so gas dissolved in the water may escape into unfilled space at the top of the container. Atmospheric gas present in that air space may also dissolve into the water sample. Other chemical reaction equilibria may change if the water sample changes temperature. Finely divided solid particles formerly suspended by water turbulence may settle to the bottom of the sample container, or a solid phase may form from biological growth or chemical precipitation. Microorganisms within the water sample may biochemically alter concentrations of oxygen, carbon dioxide, and organic compounds. Changing carbon dioxide concentrations may alter pH and change solubility of chemicals of interest. These problems are of special concern during measurement of chemicals assumed to be significant at very low concentrations.
It is used as one indicator of water quality.

Total dissolved solids

dissolved solidsTDSphosphorus
The key basic water quality parameters that need to be addressed in an emergency are bacteriological indicators of fecal contamination, free chlorine residual, pH, turbidity and possibly conductivity/total dissolved solids.
The principal application of TDS is in the study of water quality for streams, rivers and lakes, although TDS is not generally considered a primary pollutant (e.g. it is not deemed to be associated with health effects) it is used as an indication of aesthetic characteristics of drinking water and as an aggregate indicator of the presence of a broad array of chemical contaminants.

Bacteriological water analysis

microbiological analysisplate countbacteriological
Microorganisms such as fecal coliform bacteria (Escherichia coli), Cryptosporidium, and Giardia lamblia; see Bacteriological water analysis
It represents one aspect of water quality.

International Water Management Institute

International Water Management Institute (IWMI)
For example, following the 2004 Indian Ocean tsunami the Colombo-based International Water Management Institute (IWMI) monitored the effects of saltwater and concluded that the wells recovered to pre-tsunami drinking water quality one and a half years after the event.
Its research focuses on: water availability and access, including adaptation to climate change; how water is used and how it can be used more productively; water quality and its relationship to health and the environment; and how societies govern their water resources.

Bottled water

bottledwater bottlingWater
The U.S. Food and Drug Administration (FDA) regulations establish limits for contaminants in bottled water that must provide the same protection for public health.
Bottled water is bought for many different reasons including taste, convenience, poor tap water quality and safety concerns, health concerns and as a substitute for sugary drinks.

Total suspended solids

suspended solidsTSSsolids
Total suspended solids (TSS)
It is a water quality parameter used to assess the quality of a specimen of any type of water or water body, ocean water for example, or wastewater after treatment in a wastewater treatment plant.

2-Methylisoborneol

Taste and odor (geosmin, 2-Methylisoborneol (MIB), etc.)
Its odor detection threshold is very low and it is one of the chemicals with major influence on the quality of drinking water.

Biochemical oxygen demand

BODbiological oxygen demandoxygen demand
Biochemical oxygen demand (BOD)
Total BOD is of more significance to food webs than to water quality.

Water supply and sanitation in the European Union

EU drinking water directiveEU drinking water guidelinesEU standards
[[Water supply and sanitation in the European Union#Drinking water directive of 1998|The Drinking Water Directive]] (98/83/EC) of 3 November 1998 concerning potable water quality;
The Drinking Water Directive (98/83/EC) of 3 November 1998 concerning potable water quality;

Water testing

Water testing
Water testing is a broad description for various procedures used to analyze water quality.

Chemical oxygen demand

CODChemical Oxygen Demand (COD)Dissolved organic content
Chemical oxygen demand (COD)
COD is useful in terms of water quality by providing a metric to determine the effect an effluent will have on the receiving body, much like biochemical oxygen demand (BOD)...

Water quality modelling

Water quality
Water quality modelling
A typical water quality model consists of a collection of formulations representing physical mechanisms that determine position and momentum of pollutants in a water body.