Introduction to Water Treatment 060401e Flashcards
Where does essentially all of the fresh water supply come from?
Precipitation that falls on the land areas
The quantitative capacity of a water or water solution to neutralize an acid?
Alkalinity
The process of adding oxygen to water for oxidation of matter such as iron or to cause the release of dissolved gases such as dioxide or hydrogen sulphide from water
Aeration
The process in which beds of a filter or ion exchange media are subjected to flow opposite service flow direction to loosen the bed and to flush suspended matter collected during the service run to waste
Backwash
What elements when dissolved causes hardness in water?
Calcium and magnesium
What term is often used interchangeably with demineralization?
Deionization
One grain per US gallon is equal to how many milligrams per litre or parts per million?
17.1 mg/l or ppm
One grain per imperial gallon equals how many milligrams or ppm?
14.3
Trade name for a particular type of air induction or injector valve
Hydrocharger
A reversible process in which ions are released from an insoluble permanent material in exchange for other ions in a surrounding solution
Ion exchange
What is used to regenerate a manganese greensand filter?
Potassium permanganate
The percentage of TDS removed from the feed water
Rejection
Any water that contains less than 1.0 gpg of hardness minerals expressed as calcium carbonate
Soft water
The removal of calcium and magnesium, the ions with are the principal cause of hardness from water
Water softening
Porous media where grains are not connected to each other are considered what?
Unconsolidated
Media where the grains are cemented together is called what?
Consolidated
Rocks in which the groundwater moves through cracks, joints and fractures in otherwise solid rock?
Fractured aquifer
An aquifer that lies beneath layers of impermeable materials?
Confined aquifer or artesian aquifer
Aquifers that are bounded by the water table?
Unconfined awuifer
One of the most important changes in groundwater chemistry occurs where?
In the soil
What kind of wells usually contain lower amounts of hardness and other dissolved materials?
Shallow wells
What is the most common impurity in water?
Water hardness
Hardness Minerals + Heat = ?
Scale
Hardness Minerals + Soap = ?
Scum
How do you convert part per million (ppm) to grains per US gallon?
Divide ppm by 17.1
What are the 3 designations for the term hardness?
Total hardness
Temporary hardness
Permanent hardness
Very hard water is unfit for human consumption unless it is softened by treatment to less than how many grains per gallon?
12 gpg
It is recommended that hardness should not exceed how many gpg in household applications?
3.5
What causes temporary water hardness?
Bicarbonates of calcium and magnesium dissolved in water cause temporary hardness (settle out at 140°F)
What causes permanent hardness in water?
Carbonates of calcium and magnesium in addition to sulphates, nitrates and other chemicals (settle out at 299°F)
When water is evaporated, this permanent hardness remains behind in the boiler because it will not vaporize
What is point source water pollution?
When you know the cause and the point of origin
What is non-point source water pollution?
When you don’t know what’s polluting the water source
Clean rain has a pH value of what?
5.6
Water with a hardness of 0.5 gpg would be considered what?
Soft
