❖ Calibration of conductivity cells, performed annually, may be easier to execute
by the cell manufacturer at their facility.
The use of two conductivity cells for each
monitored point (loop supply and return)
may be considered. A calibrated cell
should be available for installation prior
to a scheduled annual shutdown.
❖ Distribution loop rouging should be performed annually or by on ongoing “side
stream” monitoring program. A typical location for determining the degree of rouging
is the first elbow/tee downstream of the
Purified Water Distribution Pump. As a minimum, derouging and repassivation should
be considered every two years.
❖ All diaphragms in distribution loop
valves should be replaced annually.
❖ Distribution loop sanitary ferrule gaskets
should be replaced once every three years
or more frequently if gasket leaks are noted.
❖ Monthly inspection of sanitary ferrule
clamps should be performed. Clamps
should be tightened securely.
❖ Operation of the modulating-type back
pressure regulating valve should be verified every six months.
• Dissolved (Electrolytic) Ozone Generator
The system depicted in Figure C uses
electrolytic ozone generation. Gaseous ozone
generation may also be used particularly for
high capacity (tank volume and flow rate)
systems. Electrolytic ozone generation periodic maintenance is critical. The following
maintenance program should be considered:
❖ If the electrolytic ozone generator is
equipped with “short duration” battery
back-up for cells, replace the batteries annually.
❖ Replace the anode, cathode, and semipermeable membrane in each electrolytic
❖ Verify operation and accuracy of temperature monitoring systems, including
thermal “cut-off” provisions for each cell
❖ Verify the operation of each electrolytic cell by placing any parallel cells in
“standby”, setting the cell amperage/volt-age at a predetermined value, and measuring the dissolved ozone product water
concentration by sample collection and
analysis every six months.
❖ Verify the flow of wastewater and hydrogen gas from the system monthly.
A proactive maintenance program minimizes
potential system excursions that may result in
significant manufacturing issues. While seemingly extensive, the suggested maintenance
items can be executed during scheduled facility
shutdown periods. The program provides a
truly “controlled” state for a validated system.
(1) Collentro, W.V., “Monochloramine
Removal by Activated Carbon –
Design, Operating, and Maintenance
Considerations”, presented at the
International Water Conference,
The Engineer’s Society of Western
Pennsylvania, presentation IWC 11-14,
November 13-17, 2011, Orlando, Florida
( 2) Collentro, W.V., “The Effect of
Municipal Water Treatment Techniques
on Compendial Water System Design,
Operation, and Maintenance – Case
Histories”, Pharmaceutical Processing,
Volume 28, No. 9, Reed Business
Information, Highlands Ranch, Colorado,
( 3) United States Pharmacopeia 36, National
Formulary 31 with First Supplement,
“Purified Water Monograph”, The United
States Pharmacopeial Convention, Rockville
Maryland, August 1, 2013, pg 5591
( 4) World Health Organization, “Guidelines
for Drinking-Water Quality”, Fourth
Edition, ISBN: 978 92 4 154815 1, 2011
( 5) Wu, L., and Krpan, N., “Chlorine Species
Passage through Polyamide Reverse
Osmosis Membranes, presented at the
UltraPure Water Executive Forum, May 20-
21, 2010, East Brunswick, New Jersey
( 6)Collentro, W.V., “A Novel Approach to
Control Microbial Fouling of Reverse
Osmosis Membranes”, presented at
the International Water Conference,
The Engineer’s Society of Western
Pennsylvania, presentation IWC 12-46,
November 4-8, 2012, San Antonio Texas
( 7) ASME BPE, Bioprocessing Equipment
2012, Part MJ, “Material Joining”, New
York, NY, The American Society of
Mechanical Engineers, pp 110-122
( 8) Collentro, W.V., “Pharmaceutical Water -
System Design, Operation, and Validation”,
Second Edition Informa Healthcare, ISBN
9781420077827, New York, New York,
January 2011 ■
dissolved ozone sanitization of the Purified
Water Distribution Loop. Point-of-use Purified
Water draw-off is inhibited during dissolved
ozone distribution loop sanitization. The
following maintenance program should be
❖ Replace ultraviolet lamps, quartz
sleeves, and Viton O-rings every six
months. Physical or chemical cleaning
of quartz sleeves is highly discouraged.
While greater than ultraviolet unit manufacturer’s recommended replacement
frequency, complete removal of ozone, an
antimicrobial agent, is critical.
❖ Use “certified” ultraviolet lamps. These
lamps have been “preconditioned/operated”
with ultraviolet radiation intensity verified
using a quantitative meter. The recommended ultraviolet radiation intensity meter
can be set to a value of “100%” within 24
hours of lamp replacement and verified for
about one week after lamp replacement.
❖ Clean vent fan filters for cooling lamp
❖ Semiannual inspection of the stainless
steel compression nuts for “galling of
threads”. Replace compression nuts if
❖ Retain at least two spare stainless steel
compression nuts, Viton O-rings, lamps,
quartz sleeves and ballast.
❖ If online dissolved ozone analyzers
are used, verify the absence of dissolved
ozone in product water at least once a
week using chemical analysis.
• Purified Water Distribution System and
The Purified Water Distribution Loop
delivers Purified Water to individual points-of-use with return to the ozonated Purified
Water Storage Tank. Suggested loop construction is orbitally welded 316L Stainless
Steel ( 7, 8). Point-of-use valves should be
zero dead leg type. Accessories such as
pressure gauges should be mounted on
short outlet tubing tees. The following maintenance program should be considered:
❖ Annually perform calibration of instrumentation including pressure gauges, sensing elements/transmitters/controllers, and
online analyzers (conductivity and TOC).
❖ Conduct “System Suitability” testing for
the TOC analyzer monthly and calibrate
if criteria set forth in USP Physical Tests
Section <643> are not met.