Water Treatment Equipment & Technologies Flashcards
7 cards from real CWS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Water Treatment Equipment & Technologies flashcards as text
What is the primary purpose of a brine tank in a water softener system?
Answer: To store salt used for resin regeneration
The brine tank stores salt (sodium chloride or potassium chloride) which is dissolved into a brine solution used to regenerate the ion exchange resin.
Which membrane process operates at the lowest operating pressure among the four main pressure-driven membrane technologies?
Answer: Microfiltration
Microfiltration operates at the lowest pressures (typically 5–45 psi) because it targets the largest particles — bacteria, sediment, and protozoa — requiring less driving force.
In an ultraviolet (UV) disinfection system, what component must be monitored regularly to ensure effective microbial inactivation?
Answer: UV intensity sensor (or UV transmittance)
UV intensity sensors monitor the actual UV dose delivered; reduced transmittance from fouling or lamp aging directly lowers germicidal effectiveness.
A carbon block filter is superior to a granular activated carbon (GAC) filter for removing chloramines primarily because:
Answer: The compressed block provides longer contact time with denser carbon
The compressed structure of carbon block filters forces water into closer, longer contact with the carbon media, improving chloramine reduction efficiency compared to the channeling that can occur in GAC beds.
What is 'bypass hardness' in the context of residential water softening?
Answer: Hard water intentionally blended with softened water to raise final hardness slightly
Bypass hardness refers to a controlled blending of a small fraction of hard water into the softened water stream to achieve a target finished hardness above zero, often preferred for taste.
Which type of RO membrane configuration is most commonly used in residential point-of-use systems?
Answer: Spiral-wound
Spiral-wound membranes are the dominant configuration for residential RO because they pack a large membrane surface area into a compact cylindrical housing at low cost.
What does a 'salt efficiency' rating express for an ion exchange water softener?
Answer: The amount of hardness removed per pound of salt used during regeneration
Salt efficiency is expressed in grains of hardness removed per pound of salt consumed, with higher values indicating more economical use of regenerant.