Complete this statement: The P alkalinity is exactly half the T alkalinity, therefore ______

All the alkalinity is in the carbonate form

Calculate the cubic feet of media in the ion exchange softener using the data given:
•Softener radius = 3.5 feet
•Softener height = 8.0 feet
•Media height = 2.5 feet

96 cu ft

What is a disadvantage of ion exchange softening?

Disposal of spent brine

What is a limitation of the lime-soda softening process?

Color removal may be complicated or impossible by the high pH levels

What are potential hazards of using quicklime?

Heat is produced and splashes can cause severe caustic burns

If the total hardness is greater than the total alkalinity, then

There is non-carbonate hardness present

What is a benefit of the Split Treatment Process?

Recarbonation is unnecessary

Calcium sulfate and magnesium sulfate are examples of what?

Non-carbonate hardness

When lime is added to water to be softened and the pH is increasing, which chemical reaction will occur?

Alkalinity converts from the bicarbonate form to the carbonate form, and calcium is precipitated as calcium carbonate

In ion exchange softening, what ions are exchanged?

Calcium and magesium for sodium

What are the Maximum Contaminant Limits (MCL's) for calcium and magnesium in drinking water?

There are no MCLs for Ca or Mg

At a pH value of 11.3, what has occurred?

The carbonate alkalinty has been converted to hydroxide

Calculate the alkalinity constituents as mg/L of HCO3, CO3 and OH using the following lab data:
•Total alkalinity = 185 mg/L
•P alkalinity = 102 mg/L
•pH = 9.2
You may use the Math Formula Sheets to help!

HCO3= 0, CO3= 166, OH= 19

If the water alkalinity is equal to the water hardness, all of the hardness is

Carbonate hardness

What is happening during the lime softening process at a pH of 11.3?

magnesium hydroxide precipitates

How many milligrams of CO per liter will be present in a sample if the pH is greater than 8.3?

0 mg/L

What is a common chemical used to remove non-carbonate hardness?

Sodium carbonate

Which chemical can be used in place of soda ash, and in place of all or a part of the lime used to soften water?

Sodium hydroxide

Water hardness is

A measure of the soap or detergent consuming power of water

The lab analyst finds that the total alkalinity is the same as the phenolphthalein alkalinity. Which equation below will be used to calculate the alkalinity constituents?
You may use the Math Formula Sheets to help!

P= T

The operator has overdosed the recarbonation tanks with excess CO , causing the pH to rapidly decrease from 11 to 9. What is likely to occur?

Carbonate hardness will be re-established

What ions cause a coating, or scale, to form inside the hot water heater similar to that in a tea kettle after repeated use

Calcium and magnesium

Which statement about phenolphthalein alkalinity is correct?

If phenolphthalein is present, the pH will be above 8.3, and therefore no carbon dioxide can be present

What is the purpose of adding CO2 to the softened water and bringing the pH down?

This prevents excessive scale buildup in filters, clearwells and distribution lines

In the lime/soda softening process, what happens to CaCO3 after it is formed?

It settles out

The operator of an ion exchange softening unit notices the effluent of the softener contains a hardness of one grain per gallon (1 gpg). What action should the operator take to correct the situation?

Nothing other than monitor the effluent hardness

Which statement about hardness testing is true?

EDTA is used as a titrant to an end point that is pure blue color

Split lime treatment can be used when the water contains what?

A high level of magnesium

Convert a hardness of 280 mg/L to grains per gallon

16.4 gpg