Water Treatment and Operator Certification Vocabulary

Vocabulary practice flashcards covering water treatment processes, regulations, chemistry, equipment, and plant operations.

Operator Certification Act

Act $538$ of $1972$ (Title $48$ Section $40$) that creates a committee to set forth rules and regulations for water and wastewater certification and mandates operator requirements.

Disinfection

The process of killing microbes to a safe level, specifically the destruction or inactivation of pathogens.

Sterilization

The complete destruction or killing of all living organisms.

Chlorination

The most widely used water disinfection method; cheap, easy to obtain, and leaves a residual, but dangerous and capable of creating carcinogenic disinfection by-products.

Chloramines

A disinfectant formed by combining chlorine and ammonia, ideally in the form of monochloramines.

Chlorine Dioxide

A disinfectant produced on site with a generator by mixing sodium chlorite and chlorine, effective at a pH of $8$ to $10$.

Breakpoint Chlorination

The point in chlorination where chlorine demand has been satisfied and a free chlorine residual begins to form.

Chlorine Demand

The difference between the applied chlorine dose and the remaining chlorine residual ($\text{Chlorine Demand} = \text{Dose} - \text{Residual}$).

SCBA

Self-Contained Breathing Apparatus, required when entering an atmosphere containing chlorine gas.

CT Value

The product of disinfectant concentration $C$ in $\text{mg/L}$ and contact time $T$ in minutes.

DPD

$N,N\text{-diethyl-}p\text{-phenylenediamine}$, a common reagent for field testing chlorine residual that turns pink when chlorine is present.

Amperometric Titration

The most accurate laboratory method for checking chlorine residual in water.

Rotameter

A device on a chlorinator that measures the flow of chlorine gas.

Trihalomethanes (THMs)

Carcinogenic disinfection by-products formed by chlorine reacting with organics, having a Maximum Contaminant Level ($\text{MCL}$) of $0.08\,\text{ppm}$.

Total Organic Carbons (TOCs)

Naturally occurring organic materials from decaying leaves and wood that serve as precursors to THMs.

Synthetic Organic Chemicals (SOCs)

Manmade chemicals like pesticides, herbicides, solvents, and plastics that enter water sources primarily through farmland runoff.

pH

A measurement indicating whether water is acidic, basic, or neutral, mathematically defined as the logarithm (base $10$) of the reciprocal of hydrogen ion activity.

Gravimetric Dry Feeder

A chemical feeder that feeds dry chemical compounds by weight, providing high accuracy for high-flow plants.

Volumetric Dry Feeder

A chemical feeder that feeds dry chemical compounds by volume, commonly used in low-flow plants.

Epilimnion

The upper, warmer stratum of a thermally stratified reservoir.

Thermocline

The middle stratum of a thermally stratified reservoir where temperature changes rapidly, also known as the metalimnion.

Hypolimnion

The bottom, colder stratum of a thermally stratified reservoir.

Aeration

The process of adding air to water to oxidize minerals like iron and strip volatile gases and odors.

Coagulation

The clumping together of fine particles into larger particles (floc) caused by the addition of coagulants.

Flocculation

The process of forming larger floc particles after coagulation using gentle mixing.

Sedimentation

The process where solid particles settle out of water being treated in a clarifier or settling basin.

Zeolite

A type of ion exchange material used in softeners to remove hardness from water.

SCADA

Supervisory Control and Data Acquisition system; a computerized system used to monitor plant operations, alarms, responses, and data.

Jar Test

A laboratory procedure simulating a plant's coagulation and flocculation process to determine proper chemical dosage.

Launder

A trough with V-shaped notches used to collect and transfer water from one treatment process to another.

Aluminum Sulfate (Alum)

The most commonly used primary coagulant in water treatment.

Anthracite

A filter material made from hard coal, placed at the top layer in multi-media filters.

Activated Carbon

A media used in water treatment to adsorb taste- and odor-causing compounds.

Alkalinity

The capacity of water to neutralize acids.

Schmutzdecke

The biologically active layer that forms on top of a slow sand filter.

Diatomaceous Earth

A fine silica filter media composed of the skeletal remains of diatoms.

Community Water Supply

A public water system that serves at least $15$ service connections or $25$ residents year-round.

Backflow

The reverse flow of water or other substances into the distribution pipe of a potable supply due to back pressure or back siphonage.

Back Siphonage

A form of backflow caused by negative or sub-atmospheric pressure within the water distribution system.

Cross Connection

Any physical connection between a potable water system and a source of unknown or unapproved quality.

Air Gap

An unobstructed vertical physical separation that provides maximum backflow protection, requiring at least twice the pipe diameter or $2\,\text{inches}$, whichever is greater.

Maximum Contaminant Level (MCL)

The highest permissible concentration or level of a contaminant allowed in drinking water.

Sanitary Survey

An evaluation of a public water system to identify health risks by reviewing facilities, equipment, operation, and maintenance records.

Cone of Depression

A depression in the groundwater table surrounding a well formed when groundwater is pumped out.

Drawdown

The distance between the static water level and the pumping water level inside a well.

Well Screen

An intake device placed at the bottom of a well to admit water, strain out sand, and support the aquifer walls.

Aquifer

An underground porous formation of sand or gravel capable of storing and yielding water.

Primary Contaminant

An enforceable health-related drinking water contaminant (such as lead or mercury) regulated to prevent adverse health effects.

Secondary Contaminant

A non-enforceable drinking water parameter related to aesthetic properties like taste, odor, or color.

Palatable Water

Water that is pleasant and agreeable to taste, distinct from potable water which is safe to drink.

Sequestration

A chemical process using polyphosphates to bind dissolved iron and manganese to prevent precipitation.

Apparent Color

The color of water that includes both dissolved substances and suspended particles prior to filtration.

True Color

The color of water after suspended turbidity particles have been removed.

Tuberculation

The formation of small knob-like mounds of corrosion products on the interior walls of iron pipe.

Galvanic Corrosion

Corrosion occurring when two dissimilar metals (such as copper and steel) are connected together in water.

Grab Sample

A single sample collected at a specific location and single point in time.

Composite Sample

A combination of individual samples collected over a specified period from the same location.

Indicator Organism

An organism whose presence signals the potential presence of disease-causing pathogens.

Meniscus

The curved top surface of a liquid column in a glass container or graduated cylinder.

Reagent

A substance or compound added to a system to bring about a chemical reaction or test for a target chemical.

Cavitation

A condition in a pump caused by low pressure where water boils and forms vapor bubbles, damaging the impeller and reducing efficiency.

Lantern Ring

A spacer ring located inside a pump packing gland used to feed cooling and seal water.

Pitot Tube

A device used to measure water pressure and calculate velocity and flow rate from fire hydrants and open pipes.

Altitude Valve

An automatic valve used to control the high water level in elevated storage tanks and prevent overflow.

Thrust Block

A mass of concrete installed at pipe bends or fittings to absorb hydraulic forces and prevent movement.

Confined Space

A space large enough to enter, with limited means of entry or exit, and not designed for continuous employee occupancy.