SNOWPURE, LLC, 2005-2018
VERSION 3.5 (XL+EXL)
–FEBRUARY 2018
PAGE 14
Purified Water:
Technically, water purified to USP standards. Purified Water is a
precursor to USP Water-for-Injection (WFI).
Resistivity
: the electrical measurement of water’s ability to resist the flow of electrical
current.
Resistivity increases as the concentration of ions decreases.
It is highly
affected by temperature. This measurement is associated with the level of deionization
achieved with EDI. Ultrapure water with no impurities may reach 18.24 MΩ.cm at 25°C.
Salt
: a chemical compound derived from an acid by replacing hydrogen ion wholly or
partly with a metal or electro-positive cation. Examples of salts:
Acid
Ion
Salt
HCl
Sodium ( Na
)
NaCl
H
2
SO
4
Calcium ( Ca
2
)
CaSO
4
HNO
3
Magnesium ( Mg
2
)
Mg(NO
3
)
2
H
2
SO
4
Potassium ( K
)
KHSO
4
TOC
: An abbreviation for total organic carbon, a quantitative measure of the level of
organic compounds in a water sample; expressed as ppm, or mg/liter. TOC includes all
organics, and therefore the removal of TOC varies.
USP Purified Water:
W
ater meeting USP (U.S. Pharmacopeia Monograph) quality and
process requirements (now also EP and JP) that has been purified by membranes,
distillation, ion exchange, electrodeionization, and other suitable processes, typically
from sourcewater complying with US EPA drinking water regulations, and contains no
added substances.
SnowPure EDI Intellectual Property
SnowPure, LLC, formerly HOH Water Technology, holds the O’Hare patent (US
4,465,573) that forms the basis of all EDI technology. It has improvement patents in the
works, and patents issued on its proprietary ion-exchange membrane technology (e.g.,
US 6,503,957).
Other companies hold intellectual property regarding the application of EDI technology in
systems. SnowPure, LLC does not knowingly recommend to its customers the use of
others’ intellectual property, and assumes no obligation on behalf of its customers as
they build, install, or operate EDI in systems of their design as part of their business.
EDI Technology Summary
SnowPure’s patented electrodeionization (EDI) modules have proven to be an effective
component of a continuous deionization process. Electropure™ EDI is an economic
alternative to DI mixed resin bed systems and has several advantages. Though the
capital cost of an EDI system may be higher than a resin bed system, the operating cost
a
nd other process advantages favor the use of Electropure™ EDI.