Pilot Plant Glossary of Terms

Alum

Alum is short for aluminum sulfate. This is the chemical we use to form flocs. This charges the particles and helps them stick together after they hit each other in the flocculator.

Baffles

Floc

A clump of particles stuck together with coagulant. Visible flocs in the pilot plant range in size from that of a pinhead to marble-size. Large flocs look like grayish-brown lumps that you could pick up, but they usually disintegrate upon touch.

Flocculation

The process during which particles in water form little clumps by bumping into each other and sticking together with the help of a coagulant (a substance that causes particles to stick to each other). In the pilot plant, flocculation occurs in the flocculation tank.

Lamella

Lamella are thin, gill-shaped plates held together. In sedimentation tanks, they are placed near the top of the free surface and are used to help flocs settle to the bottom of the tank.

Peristaltic Pump

Sedimentation

Because flocs are more dense than water, gravity will cause them to sink. Sedimentation is the process by which flocs settle to the bottom of a tank, leaving clear, clean water on top.

Sludge Blanket

A sludge blanket occurs when the net force on a floc is about zero. For this to occur, the water needs to be flowing from the bottom of the tank to the top. The flocs want to flow up with the water due to inertia, but because they are more dense, gravity pulls down on them. When enough flocs accumulate, they start to act as a filter for the water flowing through it. As a result of this, there is usually there is a well defined clear layer of clear water at the top of the sludge blanket

Turbidity

A measurement of how dirty water is. Turbid water looks very cloudy and hazy because of all the small particles floating around. Turbidity is how we measure the quality of our water because it tells us how many particles we have removed. It is measured in units of NTU.