CWS Reverse Osmosis Systems 2

Question 1

What is the typical recovery rate for a residential RO system?

Accepted Answer

15-25%

Answer

Residential RO systems typically recover only 15-25% of feed water as permeate, wasting 75-85% as reject.

Question 2

Which component in an RO system prevents backflow of treated water into the feed line?

Accepted Answer

Check valve

Answer

A check valve prevents back-siphonage of permeate back into the feed water supply.

Question 3

What is the primary purpose of the flow restrictor in a residential RO system?

Accepted Answer

Maintain backpressure to create reject stream

Answer

The flow restrictor maintains sufficient backpressure on the reject side to force water through the membrane and produce a concentrate stream.

Question 4

At what feedwater pressure do most residential RO membranes operate optimally?

Accepted Answer

60-80 psi

Answer

Most residential RO membranes are rated for 60-80 psi operating pressure to achieve adequate permeate production.

Question 5

Which type of RO membrane material is most commonly used in point-of-use drinking water systems?

Accepted Answer

Thin-film composite (TFC)

Answer

Thin-film composite (TFC) membranes dominate residential POU applications due to superior rejection rates and wider pH tolerance.

(CWS) Certified Water Specialist Practice Test