D2 keyterms

absorption

The taking in or soaking up of one substance into the body of another by molecular or chemical action (as tree roots absorb dissolved nutrients in the soil).

accountability

When a manager or employee gives power/responsibility to another party and ensures that the manager is informed of results or events.

accuracy

How closely an instrument measures the true or actual value of the process variable being measured or sensed.

acidic

The condition of water or soil that contains a sufficient amount of acid to lower the pH below 7.0.

acidification

The addition of an acid (usually nitric or sulfuric) to a sample to lower the pH below 2.0. The purpose of acidification is to fix a sample so it will not change until it is analyzed.

acid rain

Precipitation that has been rendered (made) acidic by airborne pollutants.

acre-foot

A volume of water that covers one acre to a depth of one foot, or 43,560 cubic feet (1,233.5 cubic meters).

activated alumina

A charged form of aluminum, used with a synthetic, porous media in an ion exchange adsorption process to remove charged contaminants.

activated carbon

Adsorptive particles or granules of carbon usually obtained by heating carbon (such as wood). These particles or granules have a high capacity to selectively remove certain trace and soluble materials from water.

acute health effect

An adverse effect on a human or animal body, with symptoms developing rapidly.

adsorbate

The material being removed by the adsorption process.

adsorbent

The material (activated carbon) that is responsible for removing the undesirable substance in the adsorption process.

adsorption

The gathering of a gas, liquid, or dissolved substance on the surface or interface zone of another material.

advanced metering infrastructure

A system that measures, collects, and analyzes energy usage while interacting with advanced devices such as water meters through various communication media.

aeration

The process of adding air to water, either by passing air through water or passing water through air.

age tank

A tank used to store a chemical solution of known concentration for feed to a chemical feeder. An age tank usually stores sufficient chemical solution to properly treat water for at least one day.

air binding

The clogging of a filter, pipe, or pump due to the presence of air released from water, which can be harmful to the filtration and backwash processes.

air gap

An open, vertical drop between a drinking (potable) water supply and the nonpotable point of use to prevent contamination.

air padding

Pumping dry air into a container to assist with the withdrawal of a liquid.

air stripping

A physical treatment process used to remove volatile substances from water or wastestreams by transferring volatile pollutants into a lower concentration air stream.

alarm contact

A switch that operates when some preset low, high, or abnormal condition exists.

algae

Microscopic plants containing chlorophyll that live floating or suspended in water, which can affect taste and odor.

algicide

Any substance or chemical specifically formulated to kill or control algae.

aliphatic hydroxy acids

Organic acids with carbon atoms arranged in branched or unbranched open chains.

aliquot

A representative portion of a sample of any given volume; often an equally divided portion.

alkali

Certain soluble salts, principally sodium, potassium, magnesium, and calcium, that combine with acids to form neutral salts.

alkaline

The condition of water or soil that contains a sufficient amount of alkali substances to raise the pH above 7.0.

alkalinity

The capacity of water to neutralize acids, expressed in milligrams per liter of equivalent calcium carbonate.

alluvial

Relating to mud or sand deposited by flowing water.

alternating current

An electric current that reverses its direction at regular intervals.

altitude valve

A valve that automatically shuts off the flow into an elevated tank when the water level reaches a predetermined level.

ambient temperature

Temperature of the surrounding air or medium.

amperage

The strength of an electric current measured in amperes.

ampere

The unit used to measure current strength.

amperometric

A method of measurement that records electric current flowing or generated.

amperometric titration

A means of measuring concentrations of certain substances in water based on the electric current that flows during a chemical reaction.

amplitude

The maximum strength of an alternating current during its cycle.

anaerobic

A condition in which atmospheric or dissolved oxygen is not present.

analog

The continuously variable signal type sent to an instrument.

analog readout

The readout of an instrument by a pointer against a dial or scale.

analyzer

A device that conducts periodic or continuous measurement of factors such as turbidity or chlorine concentration.

Angstrom

A unit of length equal to one-tenth of a nanometer.

anion

A negatively charged ion in an electrolyte solution, attracted to the anode.

anionic polymer

A polymer having negatively charged groups of ions.

anode

The positive pole or electrode of an electrolytic system.

apparent color

Color of the water including the color due to substances and suspended matter.

appropriative rights

Water rights acquired for beneficial use following a specific legal procedure.

appurtenance

Machinery and structures necessary for operation but not considered part of the main structure.

aqueous

Something containing water.

aquifer

A natural, underground layer of porous, water-bearing materials.

arch

The curved top of a sewer pipe or a bridge of hardened or caked chemical that will prevent flow.

aseptic

Free from living microbes that cause disease.

asset management

The process of maintaining functionality and value of a utility's assets through repair, rehabilitation, and replacement.

asymmetric

Not similar in size, shape, or arrangement of parts on opposite sides.

atm

The abbreviation for atmosphere; equal to 14.7 psi.

authority

The power and resources to perform a specific job.

automatic meter reading

Technology that automatically collects data from water metering devices.

available chlorine

A measure of the amount of chlorine available in compounds used for disinfection.

average

A number obtained by adding quantities and dividing the sum by the number of observations.

average daily demand

The total water demand in a period divided by the number of days.

axial to impeller

The direction in which material flows around the impeller or parallel to its shaft.

axis of impeller

An imaginary line running along the center of a shaft.

backflow

Reverse flow condition that causes water to flow back into the potable water supply from unintended sources.

back pressure

Pressure that can cause water to backflow into the water supply.

backsiphonage

Backflow caused by a negative pressure within a water system.

backwater gate

Installed at the end of a drain to prevent backup flow.

bacteria

Living organisms, usually single-celled, that play a role in decomposing organic material.

baffle

A device constructed to absorb energy and direct flow in water systems.

bailer

A length of pipe equipped with a valve to remove slurry from the bottom of a well.

ballast

A type of transformer used to limit current to an ultraviolet lamp.

base-extra capacity method

A cost allocation method used by water utilities for determining water rates.

base metal

A metal that reacts with dilute hydrochloric acid to form hydrogen.

batch process

A treatment process in which a tank is filled, treated, then emptied.

bedding

Soil placed to support a pipe ensuring uniform support along its length.

benchmark

A standard used to measure quality or value.

benchmarking

A process of gathering and comparing performance information with other similar agencies.

bench-scale analysis

A laboratory method of studying chemical doses for treatment on a small scale.

biochemical oxygen demand

A measure of oxygen consumed by organisms while stabilizing organic matter.

biofiltration

Filtering water through a medium developed with a microbial biofilm to assist in removing particulates.

biological filtration

See biofiltration.

biological growth

The activity of all living organisms.

blank

A bottle containing only dilution or distilled water.

blockout

Preventing unexpected movement of machinery or components.

blockout device

A device preventing unexpected movement during machinery operation.

BOD

Biochemical oxygen demand; a measure of oxygen consumed in organic matter decomposition.

bond

A written promise to pay a specified sum of money at a fixed time.

bonnet

The cover on a gate valve.

bowl, pump

The submerged pumping unit in a well encompassing its components.

brake horsepower

The horsepower required at the pump shaft.

breakpoint chlorination

Adding chlorine to water until demand is satisfied, leaving a free residual.

breakthrough

The occurrence of floc or particles passing through a filter.

buffer

A solution that neutralizes acids or bases to maintain pH.

buffer capacity

A measure of how much a solution can neutralize acids or bases.

caisson

A structure sunk to gain access to a water body.

calcium carbonate equilibrium

When water is saturated with calcium carbonate.

calcium carbonate equivalent

Concentration expressed in terms of calcium carbonate value.

calibration

Procedure to check or adjust an instrument's accuracy.

call date

First date a bond can be paid off.

capillary action

Water movement through small spaces due to molecular forces.

capillary forces

Molecular forces moving water through small spaces.