AWWA Water Treatment Grade 2 Definitions

Question 1

Using the chemical symbols for each element, a shorthand way of writing what elements are present in a molecule and how many atoms of each element are present in each of the molecules.

Answer 1

Chemical Formula

Question 2

The proportion calculated as a percentage, of each molecule in a compound.

Answer 2

Percent by Weight

Question 3

The sum of the atomic weights of all the atoms in the compound.
Also called the formula weight.

Answer 3

Molecular Weight

Question 4

A shorthand way, using chemical formulas, of writing the reaction that takes place when chemicals are brought together.
The left side of the equation indicates the chemicals brought together (reactants); the arrow indicates in which direction the reaction occurs; and the right side of the equation indicates the results (the products) of the chemical reaction.

Answer 4

Chemical Equation

Question 5

An indication of the relative number of molecules of the compound that are involved in the chemical reaction.

Answer 5

Coefficient

Question 6

The quantity of a compound or element that has a weight in grams equal to the substance’s molecular or atomic weight.

Answer 6

Mole

Question 7

The weight of a compound that contains one equivalent of a proton (for acids) or one equivalent of a hydroxide (for bases).
The equivalent weight can be calculated by dividing the molecular weight of a compound by the number of H+ or OH- present in the compound.

Answer 7

Equivalent Weight

Question 8

The number of equivalent weights of solute per liter of solution.

Answer 8

Normality

Question 9

A liquid containing a dissolved substance.
The liquid alone is called the solvent and the dissolved substance is called the solute.
Together, they are called a _______.

Answer 9

Solution

Question 10

In chemistry, a measurement of how much solute is contained in a given amount of solution.
These are commonly measured in milligrams per liter (mg/L).

Answer 10

Concentration

Question 11

A measurement of the amount of treated water produced by a plant each day.
It is the average of the actual daily flows that occur within a period of time, such as a week, a month, or a year.
Mathematically, it is the sum of all the daily flows divided by the total number of daily flows used.

Answer 11

Average Daily Flow (ADF)

Question 12

A measurement of the amount of water leaving a sedimentation basin per unit of basin surface area.
Mathematically, it is the flow rate from the basin divided by the basin surface area.

Answer 12

Surface Overflow Rate

Question 13

A measurement of the flow rate of water over each foot of weir in a sedimentation basin or circular clarifier.
Mathematically, it is the flow rate over the weir divided by the total length of the weir.

Answer 13

Weir Overflow Rate

Question 14

A measurement of the volume of water applied to each unit of filter surface area.
Mathematically, it is the flow rate into the filter divided by the total filter area.

Answer 14

Filter Loading Rate

Question 15

A measurement of the volume of water flowing upward (backwards) through a unit of filter surface area.
Mathematically, it is the backwash flow rate divided by total filter area.

Answer 15

Filter Backwash Rate

Question 16

An accumulation of media grains and suspended material that creates clogging problems in filters.

Answer 16

Mudball

Question 17

The average length of time a drop of water or a suspended particle remains in a tank or chamber.
Mathematically, it is the volume of water in the tank divided by the flow rate through the tank.
The units of flow rate used in the calculation are dependent on whether the time is calculated in minutes, hours, or days.

Answer 17

Detention Time

Question 18

The force pushing on a unit of area; normally measured in pascals (Pa), pounds per square inch (psi), or feet of head.

Answer 18

Pressure

Question 19

A measure of pressure.

Answer 19

Pounds per Square Inch (psi)

Question 20

1. A measure of the energy possessed by water at a given location in the water system, expressed in feet (or meters).
2. A measure of pressure (force) exerted by water, expressed in feet (or meters).

Answer 20

Head (pressure)

Question 21

Total water pressure (absolute pressure) that includes the atmospheric pressure (about 14.7 psi at sea level) exerted on water.
However, since atmospheric pressure is exerted everywhere (against the outside of the main as well as the inside, for example), it is generally not written into water system calculations.

Answer 21

Gauge Pressure (psig)

Question 22

The total pressure in a system, including both the pressure of the water and the pressure of the atmosphere (about 14.7 psi, at sea level).

Answer 22

Absolute Pressure

Question 23

A flow rate of water measured at on particular instant, such as by a metering device, involving a cross sectional area of the channel or pipe and the velocity of the water at that instant.

Answer 23

Instantaneous Flow Rate

Question 24

The average of the instantaneous flow rates over a given period of time, such as a day.

Answer 24

Average Flow Rate

Question 25

A US government agency responsible for implementing federal laws designed to protect the environment. Congress has delegated implementation of the Safe Drinking Water Act to this agency.

Answer 25

US Environmental Protection Agency USEPA)

Question 26

Non-enforceable health-based goals published along with the promulgation of an MCL. Originally called recommended maximum contaminant levels (RMCLs).

Answer 26

Maximum Contaminant Level Goal (MCLG)

Question 27

The maximum permissible level of a contaminant in water as specified in the regulations of the Safe Drinking Water Act (SDWA).

Answer 27

Maximum Contaminant Level (MCL)

Question 28

A new chemical compound formed by the reaction of disinfectants with organic matter in water. At high concentrations, many of these are considered a danger to human health.

Answer 28

Disinfection By-Product (DBPs)

Question 29

The average of four quarterly samples at each monitoring location to ensure compliance with the Stage 1 Disinfectants and Disinfectant By-Product Rule (Stage 1 DBPR).

Answer 29

Running Annual Average (RAA)

Question 30

The product of the residual disinfectant concentration C, in milligrams per liter, and the corresponding disinfectant time T, in minutes. Minimum values are specified by the Surface Water Treatment Rule as a means of ensuring adequate kill or inactivation of pathogenic microorganisms in water.

Answer 30

C x T Value

Question 31

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

Answer 31

Coagulation

Question 32

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

Answer 32

Flocculation

Question 33

A measure of how acidic or basic a substance is. The scale runs from 0 (most acidic) to 14 (most basic). The center of the range (7) indicates that the substance is neutral, neither acidic or basic.

Answer 33

pH

Question 34

A measurement of a water's ability to neutralize an acid.

Answer 34

Alkalinity

Question 35

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

Answer 35

Turbidity

Question 36

A test that determines humic content by measuring the absorbance of UV light at 254 nm and divides that value by the dissolved organic carbon concentration.

Answer 36

Specific Ultraviolet Absorbance (SUVA)

Question 36

The amount of carbon bound in organic compounds in a water sample as determined by a standard laboratory test.

Answer 36

Total Organic Carbon (TOC)

Question 37

The water treatment process that involves reducing the velocity of water in basins so that the suspended material can settle out by gravity.

Answer 37

Sedimentation

Question 38

A basin or tank in which water is retained to allow settleable matter, such as floc, to settle by gravity.

Answer 38

Sedimentation Basin (Also called a Settling Basin, Settling Tank, or a Sedimentation Tank)

Question 39

Water flowing into a basin.

Answer 39

Influent

Question 40

Water flowing from a basin.

Answer 40

Effluent

Question 41

The accumulated solids separated from water during treatment.

Answer 41

Sludge

Question 42

Uniform flow in a horizontal direction.

Answer 42

Rectilinear Flow

Question 43

Flow that moves across a basin from the center to the outside or vice versa.

Answer 43

Radial Flow

Question 44

A basin in which the coagulation, flocculation, and sedimentation processes are combined. The water flows upward through the basin and is used primarily in the lime softening of water.

Answer 44

Solids-Contact Basin (Also called an upflow clarifier or sludge-blanket clarifier)

Question 44

A clarification process in which gas bubbles are generated so that they will attach to solid particles, causing them to rise to the surface. The sludge that accumulates on the surface is then periodically removed by flooding or mechanical scraping.

Answer 44

Dissolved-Air Flotation (DAF)

Question 45

The concrete or steel basin that contains the filter media, gravel support bed, underdrain, and wash-water troughs.

Answer 45

Filter Tank or Filter Basin

Question 46

Granular media through which material is collected and stored when water passes through it.

Answer 46

Filter Media

Question 47

A filter underdrain system using a main pipe (header) with several smaller perforated pipes (lateral) branching out from it on both sides.

Answer 47

Pipe Lateral Collector

Question 48

A patented underdrain system using small porcelain spheres of various sizes in conical depressions.

Answer 48

Wheeler Filter Bottom

Question 49

A trough placed above the filter media to collect the backwash water and carry it to the drainage system.

Answer 49

Wash-Water Trough

Question 50

The practice of admitting air through the underdrain system to ensure complete cleaning of media during normal backwashing. Normally, an alternative to using a surface wash system.

Answer 50

Air Scouring

Question 51

a control valve used to maintain a fairly constant flow through the filter.

Answer 51

Rate-of-Flow Controller

Question 52

A device that measures the amount of suspended particulate matter in water.

Answer 52

Turbidimeter

Question 53

Collections 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 53

Floc

Question 54

High-molecular weight, synthetic organic compound that is used to aid in the coagulation and flocculation process.

Answer 54

Polymer

Question 55

The violent washing action in a filter caused by uneven distribution of backwash water.

Answer 55

Sand Boil

Question 56

A measurement (in millivolts) of the particle charge strength surrounding colloidal solids. The more negative the number, the stronger the particle charge and the repelling force between particles.

Answer 56

Zeta Potential

Question 57

A condition that occurs in filters when air comes out of solution as a result of pressure decreases and temperature increases. Air clogs the voids between the media grains, which causes increased head loss through the filter and shorter filter runs.

Answer 57

Air Binding

Question 58

A pressure filter using a medium made from diatoms. The water is forced through the medium by pumping.

Answer 58

Diatomaceous Earth Filter

Question 59

A reusable, welded tank that holds 2,000 lbs (910 kg) of chlorine. Thes tanks weigh about 3,700 lbs (1,700 kg) when full and are generally 30-inches (0.76 m) in diameter and 80-inches long.

Answer 59

Ton Container

Question 59

A container that holds 150 lbs (68 kg) of chlorine and has a total filled weight of 250-285 lbs (110-130 kg).

Answer 59

Chlorine Cylinder

Question 60

Any device that is used to add chlorine to water.

Answer 60

Chlorinator

Question 61

The portion of a chlorination system that feeds the chlorine solution into a pipe under pressure.

Answer 61

Injector

Question 62

A section of perforated pipe or porous plates used to inject a gas, such as carbon dioxide or air, under pressure into water.

Answer 62

Diffuser

Question 63

Chlorination using solutions of calcium or sodium hypochlorite.

Answer 63

Hypochlorinator

Question 64

An abundant element found naturally in the earth and as a result, it is found dissolved in most water supplies. When the concentration exceeds 0.3 mg/L, it causes red stains on plumbing fixtures and other items in contact with the water. This element can be present dissolved in water as a result of corrosion of cast-iron or steel pipes. This is usually the cause of red-water problems.

Answer 64

Iron

Question 65

An abundant element found naturally in the earth and dissolved in many water supplies. At concentrations above 0.05 mg/L, it causes black stains on plumbing fixtures, laundry, and other items in contact with the water.

Answer 65

Manganese

Question 66

Materials used to filter raw water, including sand, crushed quartz, garnet sand, manganese greensand, and filter coal, typically ranges in sizes from 0.25 mm to 1.20 mm, though some sizes can be smaller or larger than this range.

Answer 66

Granular Filter Media

Question 67

A piece of equipment that feeds a sodium fluoride solution into water for fluoridation. A layer of sodium fluoride is placed in a plastic tank and the water is allowed to trickle through the layer, forming a solution of constant concentration that is fed to the water system.

Answer 67

Saturator

Question 68

A procedure used to determine the concentration of fluoride ion in water; a color change takes place following the addition of a chemical reagent.

Answer 68

SPADNS Method

Question 69

A single water sample collected at one time from a single point.

Answer 69

Grab Sample

Question 70

A series of individual or grab samples taken at different times from the same sampling point and mixed together.

Answer 70

Composite Sample

Question 71

A plan for a laboratory operation that specifies the measures used to produce data of known precision and bias.

Answer 71

Quality Assurance (QA)

Question 72

A laboratory program of continually checking techniques and calibrating instruments to ensure consistency in analytical results.

Answer 72

Quality Control (QC)

Question 73

An instrument that measures a continuous sample of coagulated water. The measurement is similar in theory to zeta potential determination and provides a reading that can be used to optimize chemical application.

Answer 73

Streaming Current Detector

Question 74

A laboratory procedure for evaluating coagulation, flocculation, and sedimentation processes. This is used to estimate proper coagulant dosage.

Answer 74

Jar Test

Question 75

The most common chemical used for coagulation.

Answer 75

Alum (Aluminum Sulfate)

Question 76

The gradual deterioration of a substance or material by chemical action. The action proceeds inward from the surface.

Answer 76

Corrosion

Question 77

Metal deposits left in pipelines and plumbing fixtures.

Answer 77

Scaling

Question 78

The water treatment process intended to reduce the corrosive or scale-forming tendencies of water.

Answer 78

Stabilization

Question 79

A knob of rust formed on the interior of cast-iron pipes as a result of corrosion.

Answer 79

Tubercle

Question 80

Oxidized iron.

Answer 80

Rust

Question 81

Another name for calcium hydroxide (Ca(OH)2, which is used in water softening and stabilization.

Answer 81

Hydrated Lime (Also called Slaked Lime)

Question 82

Another name for calcium oxide (CaO), which is used in water softening and stabilization.

Answer 82

Quicklime (Also called Unslaked Lime)

Question 83

The lime slurry formed when water is mixed with calcium hydroxide (hydrated lime or unslaked lime).

Answer 83

Milk of Lime

Question 84

A conical tank, filled about halfway with calcium carbonate granules, in which softening takes place quite rapidly as water passes through the unit.

Answer 84

Pellet Reactor

Question 85

The reintroduction of carbon dioxide into the water, either during or after lime-soda ash softening, to lower the pH of the water.

Answer 85

Recarbonization

Question 86

A process used to remove hardness from water that depends on special materials known as resins. The resins trade the nonhardness-causing ions (usually sodium) for the hardness-causing ions, calcium and magnesium. The process practically removes all of the hardness from water.

Answer 86

Ion Exchange

Question 87

The process of reversing the ion exchange softening reaction of ion exchange materials. Hardness ions are removed and replaces with non-troublesome ions, thus rendering the materials fit for reuse in the softening process.

Answer 87

Regeneration

Question 88

In water treatment, the synthetic, bead-like material used in the ion exchange process.

Answer 88

Resin

Question 89

A positive ion.

Answer 89

Cation

Question 90

A negative ion.

Answer 90

Anion

Question 91

Ion exchange involving ions that have negative charges, such as chloride.

Answer 91

Anion Exchange

Question 92

The chemical compound aluminum oxide, which is used to remove fluoride and arsenic from water by adsorption.

Answer 92

Activated Alumina (AA)

Question 93

The water treatment process used primarily to remove organic contaminants from water. This process involves the adhesion of the contaminants to the adsorbent, such as activated carbon.

Answer 93

Adsorption

Question 94

Any material, such as activated carbon, used to adsorb substances from water.

Answer 94

Adsorbent

Question 95

Activated carbon in a fine powder form. It is added to water in a slurry form primarily removing those organic compounds that cause tastes and odors.

Answer 95

Powdered Activated Carbon (PAC)

Question 96

Activated carbon which is used in a bed, much like a conventional filter, to adsorb organic substances from water.

Answer 96

Granular Activated Carbon (GAC)

Question 97

The volume of the tank holding an activated carbon bed, divided by the flow rate of water. This is expressed in minutes and corresponds to the detention time in a GAC bed.

Answer 97

Empty Bed Contact Time (EBCT)

Question 98

The process of bringing water in close contact with air to remove or modify constituents in the water.

Answer 98

Aeration

Question 99

A cylindrical tank containing packing material, with water distributed at the top and airflow introduced from the bottom by a blower. Commonly referred to as an air stripper.

Answer 99

Packed Tower Aeration

Question 100

Thae ratio of the volume of product water, or permeate produced, to raw water treated.

Answer 100

Recovery

Question 101

A pressure-driven process in which almost-pure water is passed through a semipermeable membrane. Water is forced through the membrane and most ions (salts) are left behind. This process is primarily used for the desalination of sea water.

Answer 101

Reverse Osmosis (RO)

Question 102

Raw water that has undergone pretreatment (acidification or scale inhibitor addition) prior to entering the membrane arrays.

Answer 102

Feedwater

Question 103

The disposal of sludge by transporting it to a lagoon.

Answer 103

Lagooning

Question 104

A process to remove a portion of water from sludge.

Answer 104

Dewatering (Sludge)

Question 105

To draw off the liquid from a basin or tank without stirring up the sediment in the bottom.

Answer 105

Decanting

Question 106

A pump that consists of an impeller on a rotating shaft enclosed by a casing that has suction and discharge connections. The spinning impeller throws water outward at a high velocity, and the casing shape converts this high velocity to high pressure.

Answer 106

Centrifugal Pump

Question 107

The rotating set of vanes that forces water through a pump.

Answer 107

Impeller

Question 108

A product description listing a chemical's identity, composition, and type or types; the hazard(s) associated with its use; how it enters the body; the effects of exposure; health effects (short term and long term); the permissible exposure limit; how to handle spills or releases; and other related information.

Answer 108

Material Safety Data Sheet (MSDS) (or Safety Data Sheet - SDS)

Question 109

A type of respirator that supplies safe, grade D (or better) breathing air to the wearer.

Answer 109

Self-Contained Breathing Apparatus (SCBA)