Glossary of Terms

This glossary aims to provide a concise list of terms and definitions specific to our filtration solutions and used throughout our website.

ABSOLUTE

When referring to filters is used in reference to the micron rating indicating that all particles larger than a specified size will be trapped within or on the filter and will not pass through (typically 99.98%).

ABSORPTION
The process of taking up a substance into the physical structure of a liquid or solid by physical or chemical action, but without chemical reaction. 
ADSORPTION
The process by which molecules, colloids or particles adhere to the surfaces by physical action but without chemical reaction. 
BAR

Designation of pressure units. 1 bar = 14.5 psi

BUBBLE POINT
The differential gas pressure that when applied to a filter element submerged in the test fluid causes the first steady emission of gas (air) from the filter element being tested. This is a means of verifying the micrometer rating of the test element.
CHANNELLING
Often associated with wound-string or granular carbon filters, is the phenomenon of liquid forcing a channel through the filter, thus meaning that the filtration does not occur. 
CHLORINE

Chemical used for its qualities as a bleaching, oxidising or disinfecting agent in water purification.

EXTRACTABLES

Water-soluble matter, which can be eluted from a filter into the effluent.

FDA CRITERIA

The Food and Drugs Administration issues criteria for the suitability of a material for use in human food or drugs production.

FEED/FEEDWATER

The input solution to a treatment/purification system, including the raw water supply prior to any treatment.

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 are toxic to humans

HYDROPHILIC

Water-accepting

HYDROPHOBIC

Water-repelling

INTEGRITY TESTED

If a filter has been integrity tested then it has been checked after manufacture to ensure that it will perform to specification with regard to particulate and/or bacterial removal.

LOG REDUCTION

A mathematical term for a tenfold (one decimal) or 90% reduction in microbes.

LPH

Litres per hour.

MG/L

Milligrams of an element per litre of water, approximately equal to ppm.

MICRON
A metric unit of measurement equivalent to 106 metres, 104 centimetres. Symbol is µ
NOMINAL

In terms of filtration, a nominal rating describes the ability of the filter media to retain a percentage of particulate at the rated pore size.

PORE

An opening in a membrane or filter matrix.

POROUS

The ability of certain substances to pass fluids due to an open physical structure.

PPM

Parts per million, commonly considered equivalent to milligrams per litre (mg/L).

PRESSURE DROP

The decrease in pressure from one point in a pipe or tube to another point downstream.

RESINS (ION EXCHANGE)

Specially manufactured polymer beads used in the ion exchange process to remove dissolved salts from water.

REVERSE OSMOSIS

The separation of one component of a solution from another component by flowing the feed stream under pressure across a semipermeable membrane. RO concentrates ionized salts, colloids, and organics down to 150 molecular weight in the concentrate stream and provides a purified stream of water.

SHARP CUT-OFF

A feature of a filter, which means that it will remove particles of a certain size, but will leave the vast majority of smaller particles in the effluent. 

TDS

Total Dissolved Solids.

TOC

Total Organic Carbon – the amount of carbon bound in organic compounds in a water sample as determined by a standard laboratory test. The CO2
 is measured when a water sample is atomised in a combustion chamber. 

VOC

Volatile Organic Compound – synthetic organic compounds that easily volatise. Many are suspected carcinogens. 

WRAS

Water Regulations Advisory Scheme (WRAS) - The UK water industry's approval scheme