CWS Filtration Media & Technologies 2

Question 1

What is the primary mechanism by which activated carbon removes chloramines from water?

Accepted Answer

Chemical reduction catalysis

Answer

Activated carbon removes chloramines primarily through chemical reduction catalysis, not just adsorption, which is why carbon used for chloramine reduction depletes faster than for chlorine removal.

Question 2

Which filtration media is BEST suited for removing dissolved iron in its ferrous (Fe²⁺) state directly without prior oxidation?

Accepted Answer

Catalytic carbon

Answer

Catalytic carbon can reduce dissolved ferrous iron directly through catalytic oxidation, whereas most other media require pre-oxidation to convert Fe²⁺ to Fe³⁺ before filtration.

Question 3

In a multimedia filter, what is the correct layering order from top to bottom?

Accepted Answer

Anthracite, fine sand, garnet

Answer

Multimedia filters layer coarse, lighter anthracite on top, then fine sand, then dense garnet at the bottom, allowing coarser solids to be trapped at the top and finer particles deeper in the bed.

Question 4

What is the typical effective size range for sand used in a standard residential sand filter?

Accepted Answer

0.35–0.5 mm

Answer

Standard residential filter sand has an effective size of approximately 0.35–0.5 mm, which provides adequate filtration without excessive head loss.

Question 5

A customer's birm filter is failing to remove iron adequately. The most likely cause is:

Accepted Answer

Dissolved oxygen in feed water is below 15% saturation

Answer

Birm requires a minimum dissolved oxygen level of about 15% saturation to catalyze iron oxidation; insufficient DO is the most common cause of poor iron removal performance.

(CWS) Certified Water Specialist Practice Test

(CWS) Certified Water Specialist Practice Test

CWS Filtration Media & Technologies 2