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GLOSSARY OF WATER PURIFICATION AND HEALTH TERMS.
This Glossary is not meant to be all-encompassing but instead contains terms used in the different forms of purification and separation.
hardness |
The concentration of calcium and magnesium salts in water
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heavy metals |
Metals having a high density or specific gravity of approximately 5.0 or higher. The elemental weight is also high. A generic term used to describe contaminants such as cadmium, lead, and mercury. In low concentrations most are toxic to humans.
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hemodialysis |
The process of purifying a kidney patient’s blood by means of dialysis membranes
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hemolysis |
Rupturing of red blood cells sometimes occurring during hemodialysis. May be caused by the presence of chloramines in the dialysis water supply.
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High Efficiency Particulate Absolute (HEPA) |
A filter which removes from air 99.97% or more monodisperse dioctyl phthalate (DOP) particles having a mean particle diameter of 0.3 µm. Common use: “HEPA filter” high efficiency particulate air filter.
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high-purity water |
Highly-treated water with attention to microbiological reduction or elimination; the term commonly used in the pharmaceutical industry.
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housing |
A ported chamber with closure, which directs the flow of fluid through the filter element.
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humic acid |
A water-soluble organic compound composed of decayed vegetable matter which is leached into a water source by runoff. Present in most surface waters. Higher concentrations cause a brownish tint. Difficult to remove except by ultrafiltration or reverse osmosis.
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hydrocarbon |
An organic compound containing only carbon and hydrogen and often occurring in petroleum, natural gas, coal, and bitumens. Most successfully removed from water by coalescing for large volumes or by using activated carbon for small volumes.
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hydrogen sulfide |
A toxic gas (H 2 S) that is detectable by a strong “rotten egg” odor. A common by-product of anaerobic bacteria.
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hydrologic cycle |
The natural cycle of water as it passes through the environment by evaporation, condensation, precipitation, and retention in the oceans or on land.
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hydrophilic |
Water-accepting.
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hydrophobic |
Water-rejecting
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