Technical Terms and Definitions

Coagulation: The destablization and initial aggregation of finely divided suspended solids by the addition of a polyelectrolyte or a biological process.

Cryptosporidium:
A protozoan parasite that can live in the intestines of humans and animals.

Floccule or Floc:
Small, gelatinous masses formed in water by adding a coagulant, or in wastewater through biological activity.

Flocculation:
Gentle stirring or agitation to accelerate the agglomeration of particles to enhance sedimentation or flotation.

Giardia Lamblia:
A protozoan parasite responsible for giardiasis.

Microfiltration membranes:
A low-pressure membrane filtration process that removes suspended solids and colloids larger than 0.1 microns.

Nanofiltration membranes:
Low pressure reverse osmosis. Used for softening, and organic removal, including color.

Ozone Resistance:
The ability of a material to resist the oxidizing power of ozone.

Rapid Mix:
A physical water treatment process that involves rapid and complete mixing of coagulants or conditioning chemicals.

Reverse Osmosis:
A method of separating water from dissolved salts by passing feedwater through a semipermeable membrane at a pressure greater than the osmotic pressure caused by the dissolved salts.

Sedimentation:
The removal of settleable suspended solids from water or wastewater by gravity in a quiescent basin or clarifier.

Silt Density Index:
A measure of the fouling tendency of water based on the timed flow of a liquid through a membrane filter at a constant pressure.

Total Suspended Solids:
The measure of particulate matter suspended in a sample of water or wastewater. After filtering a sample of a known volume, the filter is dried and weighed to determine the residue retained.

Turbidity:
Suspended matter in water or wastewater that scatters or otherwise interferes with the passage of light through the water.

Ultrafiltration:
A low-pressure membrane filtration process that separates solutes in the 20-1000 angstrom (up to 0.1 micron) size range.