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.

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.

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.

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.

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

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