Ultra Pure Water Industry (Process)

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ULTRA PUREWATER

INDUSTRYProcess Flow


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ULTRA PURE WATER INDUSTRY

Process ObjectiveProcess Objective

Water Quality

Parameter

Units

Typical Municipal

Water Supply

Typical Ultrapure

Water Product

Resistivity M Ohms-cm 0.004 >18pH units 8 6

TOC ppb 3500


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ULTRA PURE WATER INDUSTRYProcess Flow Schematic Diagram


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ULTRA PURE WATER INDUSTRYProcess Flow Schematic Diagram


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ULTRA PURE WATER INDUSTRYProcess Operation

} Feed Tank

}

typically pumped from either a local well orfrom a municipal water treatment plant to

raw water storage tank

} Pump from storage tank provide a pressurefor a steady-state flow in early pre-

treament


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} Pre-Treatment

} Filtration- multimedia filters (a combinationof gravel, sand and anthracite) and/or

activated carbon filtration

} Chemical Treatment - pH adjustment, suchas an acid injection, and possibly a chlorine

reducing agent, such as sodium bisulfite.


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} Reverse-Osmosis (RO)

} The RO process is considered to be the workhorseworkhorse

of the UPW system

} Typically removesremoves >98% of all dissolved solids, TOC,

silica and particles from the feedwater stream

}} consumeconsume a significant amount of the energy and

chemicals required to maintain a dependable

UPW system} To ensure effectiveness, UPW systems contain dualdual

passpass RO systems, in which two RO systems arearranged in series.


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} Vacuum Degasification (DEGAS)

} Depending on the amount of chemicalpre-treatment, RO permeate water usuallycontains undesirableundesirable dissolved gasses suchas carbon dioxide and oxygen

} These gases are mostly removedremoved with avacuum degasifier.

} These gases and other volatile compoundsare liberated and removed in the vaporisevaporiseflow.


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}Main RO Storage Tank

}

Typically lined with an inertlined with an inert polymer coatingsuch as polyvinylidene fluoride (PVDF)

} also blanketed with high purity nitrogenblanketed with high purity nitrogen to

prevent contamination from the air andmaintain high levels of purity

} When the tanks are full, water from themake-up system is diverted back to the raw

water storage tank


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}Mixed Bed Ion Exchange (EDI)

} Two different resins are utilized to performspecific ion exchange functions

} The cationcation resinsresins chemically exchangeundesirable aqueous cations (e.g., Na+, Ca2+,Mg2+, etc.) with a hydrogen ion (H+) from theresins functional group.

} Undesirable aqueous anions (e.g., Cl-, SO42-,

etc.) are exchanged with a hydroxyl molecule(OH-) attached to the anion resinsanion resins.


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} Ultraviolet Oxidizer/Sterilizers (UV)

} Ultraviolet processes serve different functions in a UPWsystem dependingdepending on their location and the

wavelength of light emitted} Primary functions include:

a) 185 nm UV light is typically used for the reductionreduction oforganic compounds.

b) 254 nm UV light is typically used fordestructiondestruction ofbacteria.

c) 254 nm UV light is typically used for the conversionconversionof ozone and hydrogen peroxide to dissolved oxygenand water


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} Ultrafilter skid

}} higher molecular weight cutoffhigher molecular weight cutoff than ROmembranes but require less energy toproduce equal volumes of permeate

} well suited for the removalremoval of colloidal silica,endotoxins or pyrogens that may becreated by other systemcreated by other system components

located upstream.} employed towards the backendbackend of a UPW

system for these reasons.

Ultra Pure Water Industry (Process)

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