Water Exam Class B

Question 1

Eutrophication in surface water sources is caused by elevated concentrations of what two things?

Answer 1

Nitrogen and phosphorus

Question 2

Lake “turnover” occurs when water cools off during what season?

Answer 2

Fall

Question 3

Alum is used as a what?

Answer 3

Coagulant

Question 4

The most common forms of alkalinity in natural water are what?

Answer 4

Bicarbonate and carbonate

Question 5

Non-carbonate hardness in water includes what?

Answer 5

CaCl2

Question 6

If you increased the pH by 2 units, it would ___________ the hydrogen ion concentration by _____ times.

Answer 6

Decrease, 100

Question 7

What treatment chemical will raise the pH?

Answer 7

Lime

Question 8

The dominant form of natural alkalinity at pH less than 8.3 is what?

Answer 8

Bicarbonate

Question 9

The pH of a sample should be measured when?

Answer 9

Immediately after collection

Question 10

The Total Coliform Test vial contains a chemical preservative that destroys what?

Answer 10

The chlorine residual

Question 11

What health problems are caused by lead in the drinking water, and what is the action level established in the lead and copper rule?

Answer 11

Central nervous system disorders, 0.015 mg/L

Question 12

Treatment to reduce corrosiveness of water to lead includes raising the what?

Answer 12

pH

Question 13

The Filter Backwash Recycle Rule is intended to minimize potential health risks associated with recycling backwash water particularly with respect to what?

Answer 13

Cryptosporidium

Question 14

The Long-Term 2 Enhanced Surface Water Treatment rule established levels of disinfection based on the concentration of what found in the source water?

Answer 14

Cryptosporidium

Question 15

Source water sampling is triggered by the Ground Water Rule when an unsafe _________ __________ _________ sample is obtained.

Answer 15

Total Coliform Rule

Question 16

The Surface Water Treatment Rule requires that the turbidity of the combined filter effluent water is less than or equal to _____ in at least _____ of the measurements taken each month.

Answer 16

0.5 NTU, 95%

Question 17

The Interim Enhanced Surface Water Treatment Rule and Long Term 1 Enhanced Surface Water Treatment rule allowed 99% Cryptosporidium removal credit to be achieved when the combined filter effluent water is less than or equal to _______ in at least ______ of measurements taken each month.

Answer 17

0.3 NTU, 95%

Question 18

The charge on a particle measured at the shear surface is called the what?

Answer 18

Zeta potential

Question 19

Clay particles typically have a _____________ charge due to the imperfections in the clay structure.

Answer 19

Negative

Question 20

Charge neutralization, sweep floc, and interpartical bridging are all what?

Answer 20

Coagulant mechanism

Question 21

The coagulation mechanism accomplished with polymer coagulants is what?

Answer 21

Interparticle bridging

Question 22

Alum and Ferric chloride coagulants do not raise the what?

Answer 22

pH

Question 23

The polymer charge that would be selected to coagulate a clay suspension is what?

Answer 23

Cationic +

Question 24

When viewing jar test results the coagulant dosage that would be chosen for trial in a full scale water plant is the __________ dosage with the best ______________.

Answer 24

Lowest, turbidity

Question 25

Organic matter can be effectively removed by coagulation because it is _____________ charged and is co-precipitated or ___________ by the coagulant.

Answer 25

Negatively, absorbed

Question 26

Optimizing coagulation to remove TOC is called what?

Answer 26

Enhanced coagulation

Question 27

Organic matter removal in lime softening works best with what two things?

Answer 27

High pH with magnesium removal

Question 28

A complete mix flow regime is desired for what two things?

Answer 28

Chemical feed and mixing

Question 29

When the water remains in the process tank for an amount of time equal to the theoretical detention time, the process is exhibiting what?

Answer 29

Plug flow

Question 30

One advantage of static mixers is that they require what?

Answer 30

Little maintenance

Question 31

A measure of power input per unit volume of a mixing system is what?

Answer 31

Mean velocity gradient

Question 32

Detention time in a back mix reactor for chemical mixing a coagulant is usually what?

Answer 32

1 minute or less

Question 33

Decreasing the G-Value in successive stages of flocculation is called what?

Answer 33

Tapered flocculation

Question 34

Typical G-values in flocculation range between what?

Answer 34

25 and 75 /sec

Question 35

The settling velocity of the slowest settling particle that is 100% removed in a clarifier is equivalent to the what?

Answer 35

Surface overflow rate

Question 36

A typical surface overflow rate for alum clarification is what?

Answer 36

800 gpd/ft2

Question 37

If solids are carrying over the weir in a clarifier the flow through the basin may have ___________ the design flow.

Answer 37

Exceeded

Question 38

Typical loading rates for a rapid rate granular media filters range from what?

Answer 38

2 to 4 gpm/ft2

Question 39

Water backwash, surface wash, and air and water backwash are all options for what?

Answer 39

Filter backwash

Question 40

What uses a valve on the discharge side of the filter to control the flow rate?

Answer 40

Effluent rate control

Question 41

What eliminates the initial effluent turbidity spike when starting a filter after a backwash?

Answer 41

Filter to waste

Question 42

A common way to prevent air binding would be to do what more frequently?

Answer 42

Backwash

Question 43

Ultra filter pore sizes are in the range of what?

Answer 43

0.01 to 0.05 microns

Question 44

Nanofilters can remove what two things?

Answer 44

Calcium, natural organic matter (TOC)

Question 45

A required test conducted daily to determine if broken fibers exist in a microfilter is called a what?

Answer 45

Direct integrity test

Question 46

Under a constant feed pressure, as raw water temperature decreases, the flux through a polymeric membrane will what?

Answer 46

Decrease

Question 47

A Clean In Place (CIP) procedure for an RO membrane to remove inorganic scaling will normally be accomplished with what?

Answer 47

Strong acid

Question 48

Calcium carbonate hardness is removed by ______________ by raising the pH to convert bicarbonate to ______________, the precipitate is _________.

Answer 48

Precipitation, carbonate, CaCO3

Question 49

Magnesium hardness is precipitated as what?

Answer 49

Mg(OH)2

Question 50

Which treatment objective is not achieved in the lime softening process?

Answer 50

Sulfate removal

Question 51

From a chemical cost perspective, the most expensive hardness to remove by lime - soda precipitation softening is what?

Answer 51

Magnesium non-carbonate hardness

Question 52

Recarbonation after lime softening lowers the pH so that the water is slightly over saturated with respect to what?

Answer 52

Calcium carbonate

Question 53

Iron is groundwater is what?

Answer 53

Dissolved, reduced

Question 54

The secondary standard for manganese is what?

Answer 54

0.05 mg/L

Question 55

At the natural pH of ground water, manganese is most rapidly oxidized with what?

Answer 55

Permanganate

Question 56

Greensand filters routinely include a layer of what above the greensand?

Answer 56

Anthracite

Question 57

Greensand filters are regenerated using what?

Answer 57

Permanganate

Question 58

Disinfection with what adds acid to the water and can lower water pH?

Answer 58

Gas chlorine

Question 59

To optimize monochloramine formation, the chlorine to ammonia ratio should be what?

Answer 59

5:1

Question 60

What is a very weak disinfectant?

Answer 60

Chloramine

Question 61

Free chlorine disinfection is more effective at a pH < 7.5 due to a greater percentage of ________ in the residual.

Answer 61

HOCL, hypochlorous acid

Question 62

Organic matter reacts with free chlorine to form what?

Answer 62

THM (Trihalomethanes), HAA (Haloacetic acids)

Question 63

THM (trihalomethanes) formation potential increases as the pH what?

Answer 63

Increases

Question 64

The time used to calculate CT (concentration time) is the detention time between the chlorine application point and the what?

Answer 64

First user

Question 65

A disinfection byproduct that can form when ozone is used as the disinfectant is what?

Answer 65

Bromate