Lab Water purification


Absorption A process by which a substance is taken up chemically or physically by an absorbent material and held in pores or interstices
Aquifer A natural underground water, often of sand or gravel, that contains water
Action Level The level of lead and copper which, if exceeded, triggers treatment or other requirements that a water system must follow
Activated carbon A highly porous form of carbon used for sorption of organics and removal of some components
Adsorption Adherence of molecules, atoms and ionized species of gas or liquid to the surface of another substance
Anion Exchange Resin An ion exchange resin with immobilized positively charged exchange sites, which can bind negatively charged ionized species, anions



Backwash The upward flow of water through a resin or carbon bed to clean it, and in the case of a mixed bed, to separate anion and cation resins
Bactericide An agent to kill bacteria
Biocide An agent to kill micro-organisms
Biofilm A layer of micro-organisms and chemical products which are adherent to each other and / or to surfaces



Cartridge A disposable container that houses water purification resins, media or membranes
Cation Exchange Resin An ion exchange resin with immobilized negatively charged exchange sites, which can bind positively charged ionized species, cations
CFU/ml Colony Forming Units per 1 millilitre
Coliform A group of related bacteria whose presence in drinking water may indicate contamination by disease-causing micro-organisms
Colloid A stable dispersion of particles in water with a size less than 0.1 um. Colloids are founds in natural and potable water
Community Water System A water system that supplies drinking water to 25 people or more year-round in their residences
Condenser The part of a distillation system that removes heat from a vaporized liquid to cause the vapour to change to a liquid phase
Conductivity Reciprocal of resistivity (micro-siemens per centimetre at 25°C)
Contaminant Anything found in water (including micro-organisms, radionuclides, chemicals, minerals, etc.) which may be harmful to human health
Cryptosporidium Micro-organisms found commonly in lakes and rivers which is highly resistant to disinfection



Degassing The removal of O2 and CO2 from water
Deionization Removal of impurity ions from water
Disinfectant A chemical (commonly chlorine, chloramines, or ozone) or physical process (e.g.: ultraviolet light) that kills micro-organisms such as viruses, bacteria and protozoa)
Distillation Purification process that changes the phase of a substance from liquid to vapour and back to liquid, usually at the boiling temperature of the substance, in order to separate substances with different boiling points
Distribution System A network of pipes leading from a treatment plant to customer’s plumbing system



Endotoxin Lipopolysaccharide component from the cell wall of viable or non viable gram-negative micro-organisms (Pyrogen)
Endotoxin unit A quantification of endotoxin presence relative to a specific quantity of reference endotoxin. 1 EU/ml is appr. equal to 0.1 ng/ml
Epifluorescence Fluorescence microscopy to be used to detect bacteria enumeration after filtration and staining
Exotoxin Toxin substance secreted by a bacterium, often causing disease



Feed water Water that is introduced into a purification process



Gram-negative Bacteria that do not absorb a stain as described by Gram
Gram-positive Bacteria that absorb a stain as described by Gram
Ground Water Water that is pumped and treated from an aquifer



Hardness The scale-forming of some water supplies, caused by high concentrations of Ca and Mg



Inorganic Contaminant Mineral-based compounds such as metals, nitrates, and asbestos; naturally occurring in some water, but can also enter water through human activities
Ions Particles with positive or negative electric charge
Ion Exchange Process of purifying water by removing ionised salts form solution



LAL Limulus Amebocyte Lysate. An extract from the Horseshoe crab which form a gel in presence of sufficient endotoxin



Maximum Contaminant Level The highest level of a contaminant that EPA allows in drinking water (legally enforceable standard)
Maximum Contaminant Level Goal The level of a contaminant at which there would be no risk to human health (not a legally enforceable standard)
Micro-organisms Tiny living organisms that can be seen only under a microscope; some can cause acute health problems when consumed in drinking water



Non-Transient Non-Community Water System
A non-community water system that serves the same people more than six months of the year, but not year-round



On-line Measurement device directly coupled to a water stream
Organic Contaminants Carbon-based chemicals, such as solvents and pesticides, which enter water through cropland runoff or discharge from factories



Particulates Solid matter dispersed in water
Pathogen Disease-causing organism
Permeate Purified solution which has been produced by passage through a semi-permeable osmosis membrane
Potable water Water that meets regulations and is suitable for human consumption
PPB Parts per billion. Unit equal to microgram per kilogram of water
PPM Parts per million. Unit equal to milligram per kilogram of water
PPT Parts per trillion. Unit equal to nanogram per kilogram of water
Pre-treatment cartridge Disposable cartridge containing chemicals for the removal of chlorine, particles and other products prior of RO
Pyrogen Substances that can produce fever if injected or infused
Public Water System A water system which supplies drinking water to at least 25 people, at least 60 days each year



Qualification Act to document that the process, equipment and materials are designed, installed, operated and perform according to the original specifications



Regenaration Method to reactivate the exhaust ion exchange resin with acid or alkali
Resistivity Resistivity is reciprocal of conductivity. The value is reported as megohm-centimetre at 25°C
Reverse Osmosis (RO) Process in which water is forced under pressure through a semi-permeable membrane leaving behind dissolved organic, dissolved ionic and impurities



Sanitization Chemical or physical process to reduce contamination from micro-organisms
Sensitive Sub-population People who may be more vulnerable to drinking water contamination, such as infant, children, some elderly, and people with severely compromised immune systems
Septic System Used to treat sanitary waste; can be a significant threat to water quality due to leaks or runoff
Softening Water treatment process where cations are exchanged for Na using cation exchange resin
Source Water Water in its natural state, prior to any treatment for drinking (i.e.: lakes, streams, ground water)
Sterilization Destruction (e.g.: by heating) or removal (e.g.: by filtration) of all living micro-organisms
Surface Water Water that is pumped and treated from sources open to the atmosphere, such as rivers, lakes, and reservoirs



Total Dissolved Solids (TDS) Total organic and inorganic salts dissolved in water, obtained by drying residue at 180°C
Total Organic Carbon (TOC) Total carbon present in organic compounds
Transient Non-Community Water System
A non-community water system that serves the public but not the same individuals for more than six months



Ultra-filtration Water is filtered through a special membrane with a very fine structure


Validation Confirmation that specific intended use has been fulfilled

Violation Failure to meet any state or federal drinking water regulation
Vulnerability Assessment An evaluation of drinking water source quality and its vulnerability to contamination by pathogens and toxic chemicals


Watershed The land area from which water drains into a stream, river, or reservoir
Well A bored, drilled or driven shaft whose depth is greater than the largest surface dimension, a dug hole whose depth is greater than the largest surface dimension, an improved sinkhole, or a subsurface fluid distribution system.