Ch. 4 WQC - Basic Principles of Chemistry and Electricity

Solution

A liquid containing dissolved substances

Solvent

The substance that another substance is dissolved into

Solute

The substance that gets dissolved into the solvent

Concentration

The strength of a solution; number of molecules of a substance in a given volume (mg/L)

Precipitate

Solid particles which settle out of a solution by a chemical reaction

Precipitation

The chemical process that forms a precipitate

Chemical compound

Two elements combined together

Why does chlorine degrade over time?

Chemicals used for coagulation

Aluminum sulphate or sodium silicate

Chemicals used for disinfection

Calcium hypochlorite, chlorine, chlorine dioxide, sodium hypochlorite

0 - 6 pH

Acidic

8 - 14 pH

Basic

Chemicals used for pH adjustment

Calcium hydroxide, sulphuric acid

Sodium hypochlorite degradation factors

Concentration

Light

Heat

pH

Metals

Half life of sodium hypochlorite

Half life is the time required for a solution to lose half of its strength

The shorter the half life, the less stable the solution

Hydraulics

The study of water or another liquid in motion

Pressure

The amount of force acting on a certain area

Pressure head

The pressure on the water in the reservoir feeding a pump. In an open system, this is atmospheric pressure

Head

the vertical height of a static column of fluid

Static pressure

The pressure of a fluid at rest

Residual pressure

The pressure of a fluid in motion

Head loss

The pressure loss due to friction as the water flows through the pipe due to the roughness of the pipe walls or restrictions in the pipe

Water hammer

A force caused by a sudden change of water velocity; can cause water mains to rupture

Hydraulic grade line

The line that connects the head along a pipeline or through a treatment plant

Velocity

Thrust

the force water exerts as it changes direction

can be controlled with thrust blocks

Flow rate

Cavitation

the formation and collapse of a bubble or gas pocket, can damage the impeller or gate

can be detected from loud noises and vibration

Friction loss

the loss of pressure due to flow of water in a pipe

determined by the pipe size, roughness of pipe surface, flow rate, and length of pipe

Single-phase

Only one phase of power is supplied to the main electrical panel

Three-phase

Has higher efficiency

Fuse

A protective device having a strip or wire of fusible metal, which when placed in a circuit, will melt and break the electrical circuit when subjected to extreme temperatures

Current-limiting fuse

These fuses open quickly while clearing a short-circuit current so that the potential fault current is not allowed to reach its peak

Dual-element fuse

These fuses provide a time delay in the low overload range and a fast acting element for short circuit protection

Ground fault interruption

A safety device that automatically cuts off electrical power when it detects an imbalance between incoming and outgoing current, preventing electrical shock.

Circuit breaker

A device that automatically interrupts electrical flow in a circuit when it detects an overload or short circuit, protecting the system from damage.

Electron

Smallest unit of electricity

Current

Rate at which electrons flow

Voltage

Electric potential

Resistance

A material’s tendency to restrict or resist the flow of current

Voltage drop

The flow of electricity through a wire is accompanied by a voltage drop, as a result of the resistance of the wire

Conductor

A material offering little resistance to the flow of elecricity, like copper, aluminum, and iron

Power

The ability of electricity to do a certain amount of work in a period of time

Kilowatt-hour

The amount of work done

Direct current

An electric current that flows continuously in one direction

Alternating current

An electrical current that reverses direction of flow at regular intervals

Ohm’s Law

in an electrical circuit, the amount of current in amperes is equal to the pressure in volts divided by the resistance (R) in ohms.