Chapter 8 - Coagulation and Flocculation

Question 1

Finely divided solids, such as bacteria and fine clay particles, that will stay suspended in water for long periods of time.

Answer 1

Non-Settleable Solids

Question 2

A physical characteristic of water making the water appear cloudy.
The condition is caused by the presence of suspended matter.

Answer 2

Turbidity

Question 3

A term that describes the treatment process used by most US surface water systems consisting of the steps of coagulation, flocculation, sedimentation, and filtration.

Answer 3

Conventional Treatment

Question 4

The water treatment process that causes very small particles to attract one another to form larger particles.
This is accomplished by the addition of a chemical that neutralizes the electrostatic charges on the particles that cause them to repel each other.

Answer 4

Coagulation

Question 5

The water treatment process, following coagulation, that uses gentle stirring to bring suspended particles together so that they will form larger, more settleable clumps called floc.

Answer 5

Flocculation

Question 6

A solid organic and inorganic particle that is held in suspension by the action of flowing water.

Answer 6

Suspended Solid

Question 7

A collection of smaller particles (such as silt, organic matter, and microorganisms) that have come together (agglomerated) into larger, more settleable particles as a result of the coagulation-flocculation process.

Answer 7

Floc

Question 8

A denser and heavier suspended solid that will settle unaided to the bottom of a sedimentation basin within 4 hours.

Answer 8

Settleable Solid

Question 9

A finely divided solid that will not settle out of water for very long periods of time unless the coagulation-flocculation process is used.

Answer 9

Colloidal Solid

Question 10

Any material that is dissolved in water and can be recovered by evaporating the water after filtering the suspended material.

Answer 10

Dissolved Solid

Question 11

The accumulated solids separated from water during treatment.

Answer 11

Sludge

Question 12

A coagulant aid used to form a denser, stronger floc.

Answer 12

Activated Silica

Question 13

A material, such as bentonite clay, added to low-turbidity waters to provide additional particles for good floc formation.

Answer 13

Weighing Agent

Question 14

High-molecular weight, synthetic organic compound that forms ions when dissolved in water.
Also called a polymer.

Answer 14

Polyelectrolyte

Question 15

A process of quickly mixing a chemical solution uniformly through the water.

Answer 15

Rapid Mixing

Question 16

A device designed to produce turbulence and mixing of chemicals with water, by means of fixed sloping vanes within the unit, without the need for any application of power.

Answer 16

Static Mixer