Demineralization Flashcards
Specific conductance is the indirect measurement of what parameter?
TDS ( total dissolved solids)
The TDS ( total dissolved solids) is what percent of the specific conductance?
70%
What is the pumping pressure used in RO ( reverse osmosis) treatment?
500-1200 PSI
What is the pumping pressure used in a membrane softening?
100 - 500 PSI
What is a pretreatment process in RO ( reverse osmosis) treatment?
Add acid ( sulfuric acid)
What is the purpose of pre-filters?
Particulate safeguards
To increase the flow through the membrane in RO ( reverse osmosis) treatment, what action is needed?
Increase pumping pressure
When the feed water temperature increases, what happens?
Product water increases
What is the TDS ( total dissolved solids) content of seawater?
35,000 mg/L
When pressure is increased in RO treatment, what reaction happens with the mineral flow?
Mineral flow is not affected by the PSI increase
Why is acid added to RO pre-treatment?
Prolong life of cellulose acetate membrane and prevent/control scaling
What is used to clean fouled membranes?
Citric acid and bactericide
When the water pressure must be increased by 15%, what action is needed?
Clean membranes
When recovery decreases by 15%, what action is needed?
Clean membranes
What do you call the decline in flow due to fouling and membrane compaction?
Flux decline
By arranging the membranes in a Christmas tree configuration, what recovery percent is normal?
85% or better?
What type of pump is used for desalination of water?
Positive displacement
What type of pump is used for membrane softening?
Centrifugal
If the brine valve is fully closed, what happens to the recovery percentage?
100% recovery and damage to the membranes
What type of piping is used for desalinating water?
high grade stainless steel
To minimize concentration polarization, what action is necessary?
Create turbulence by varying flow velocity
