Glossary

The world of water has a lot of jargon and tricky vocabulary. We work in the business, and we mix up technical words from time to time. Here’s a handy list of terminology to make sure we are on the same page. Where there is latitude in the definition of a word, we have chosen the definition that we believe is generally understood.

Water filter

(we will take REI's lead here) a microfilter that reduces harmful bacteria and protozoan cysts.

Water purifier

a treatment mechanism that meets the U.S. EPA standard for reducing bacteria, virus and protozoan cysts. This is 6 log reduction (99.9999%) of bacteria, 4 log reduction (99.99%) of virus, and 3 log reduction (99.9%) of cysts.

Water treatment

general term to describe some action to improve the quality of water. This could refer to any improvement in water quality – microbiological or other.

Microfiltration

a type of physical filtration process where a contaminated fluid is passed through a special pore-sized membrane to separate microorganisms and suspended particles from the process liquid.

Log reduction value (LRV)

is a mathematical term used to show the relative reduction of microbes in a given sample. 1 log reduction means the number of microbes is 10 times smaller. 6 log reduction means the number of microbes is 1,000,000 times smaller. When you perform a microbiological test you measure the number of bacteria in the influent water and then you count the number of bacteria that come out in the effluent water sample. This is the industry standard methodology for measuring the effectiveness of a water treatment device.

Microorganism

An organism that can be seen only with the aid of a microscope and that typically consists of only a single cell. Microorganisms include bacteria, protozoans, and certain algae and fungi. We exclude virus from this term.

Microbe

a microscale entity, especially a bacterium that causes disease. There is some variation in the use of this term, but we have chosen to consider virus as a microbe.

Microbiological

concerning microorganisms and their effects on other living organisms. We include virus as a microbiological entity as it has an effect on other living organisms.

Bacteria

a member of a large group of unicellular microorganisms that have cell walls but lack organelles and an organized nucleus, including some that can cause disease. Common disease causing bacteria include certain strains of E.Coli, Vibrio (Cholera), Salmonella (Typhoid), Botulism, and Campylobacter

Protozoan cyst

infectious form of many protozoan parasites (Entamoeba histolytica, Giardia lamblia, Balantidium coli) usually passed in the feces and provided with a highly condensed cytoplasm and resistant cell wall.

Virus

an infective agent that typically consists of a nucleic acid molecule in a protein coat, is too small to be seen by light microscopy, and is able to multiply only within the living cells of a host.

Particle

in regards to water we define this as any small portion of matter. This could refer to a microbe or a speck of solid material.

Turbidity

the cloudiness or haziness of a fluid caused by large numbers of 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.