Filtration

Question 1

The release of dissolved Air in saturated cold water due to a decrease in pressure causes Which of the following?

Answer 1

Air binding

Question 2

The color in filtered water is called?

Answer 2

True color

Question 3

What is the final step for removal of suspended solids?

Answer 3

Filtration

Question 4

What FAC chapter addresses drinking water standards, monitoring, and reporting?

Answer 4

FAC 62-550

Question 5

Inaccurate test results are generally due to?

Answer 5

Poor sampling techniques

Question 6

What is the highest possible turbidity reduction expected when operating a filtration process under optimum conditions ?

Answer 6

99.5%

Question 7

How is pin point floc removed?

Answer 7

Filtration

Question 8

Direct filtration omits which process?

Answer 8

Sedimentation

Question 9

What are the main removal mechanisms in a filter?

Answer 9

Absorption and sedimentation

Question 10

Sand drying beds are similar to what type of filters?

Answer 10

Gravity sand filters

Question 11

Which of the following coagulants is generally used as a filter aid?

Answer 11

Non-ionic polymer

Question 12

What parameters are used to determine when to backwash a filter?

Answer 12

Head loss, turbidity, and time

Question 13

Where is the application point for a filter aid?

Answer 13

Filter influent

Question 14

Before starting the backwash process, what must you check first?

Answer 14

Water supply

Question 15

Mud balls are caused by which of the following?

Answer 15

Improper backwash

Question 16

During a plant walkthrough, and operator discovers a filter is air bound. What action should they take?

Answer 16

Backwash the filter immediately

Question 17

Media boils are caused by?

Answer 17

High backwash rates

Question 18

What is the main goal of filtration?

Answer 18

Removal of turbidity

Question 19

What is the fourth step in the backwash process?

Answer 19

Start the surface scours

Question 20

How should an air bound filter be Backwash?

Answer 20

Slowly

Question 21

The color in unfiltered water is called

Answer 21

Apparent color

Question 22

After backwashing a filter, there is a high initial head loss. What is most likely cause?

Answer 22

Insufficient backwash

Question 23

What causes air binding?

Answer 23

Operating the filter at high head loss too long or the release of O2 in saturated cold water due to a decrease in pressure

Question 24

During a plant tour, an operator noticed the filter 16 has a sudden increase in head loss. What action should they take?

Answer 24

Do a jar test

Question 25

What do you call the process of reversing the flow of water through filter media to remove trapped particles?

Answer 25

Filter backwash

Question 26

The common boundary layer between two substances such as water and a solid is called?

Answer 26

Interface

Question 27

⭐. The difference between the water surface and the media surface is called

Answer 27

Submergence ( head)

Question 28

What is the filter rate in GPM/ sq ft of slow sand filters?

Answer 28

0.015 - 0.15 GPM/ sq ft

Question 29

⭐. High water temperatures require what type of backwash rates?

Answer 29

Higher backwash rates

Question 30

The filter backwash will requires the backwash water to be sent where after dewatering the sludge?

Answer 30

Upstream of all conventional or direct filtration systems ( includes coagulation, filtration, and sedimentation)

Question 31

⭐. What is the ripening period of a filter?

Answer 31

This occurs at upstart of the new filter and after backwashing a filter

Question 32

What is the backwash rise rate in inches/minute if the backwash flow rate is 35 GPM/SQ FT?

Answer 32

56 IN/ min

Question 33

***What is the backwash pumping rate in GPM for a filter 20 ft long and 30 ft wide with a desired backwash rate of 25 GPM/ square foot?

Answer 33

15,000 GPM

Question 34

During a filter run, flow through the filter was 12.8 million gallons. It took 120,000 gallons to backwash the filter. What percent of the filter's water production was used for Backwashing?

Answer 34

1%

Question 35

⭐. What is the minimum treatment required for drinking water by the surface water treatment rule? ( SWTR)

Answer 35

Filtration and disinfection

Question 36

⭐. Where should you install a particle counter at a WTP (water treatment plant)?

Answer 36

As close as possible to the point of measurement

Question 37

⭐. The length of a sample line of a particle counter should be how long?

Answer 37

As short as possible

Question 38

⭐. Pumping sample water to the particle counter may cause what problem?

Answer 38

Air bubbles, which may be erroneously counted as particles

Question 39

⭐. What material is recommended for the sample line of a particle counter?

Answer 39

Black nylon with Hytril liner

Question 40

What is the final step for removal of suspended solids?

Answer 40

Filtration