■ 16 NOV/DEC 2013 | PHARMACEUTICAL PROCESSING
■ PHARMPRO. COM
placement with new media. For systems
with chloramines in feed water, the replacement frequency of activated carbon
media should be once every six months,
maximum. Replacement media should be
acid washed, neutralized, and rinsed catalyt-ic-type. For units with chlorine (
hypochlorous acid/hypochlorite ion) in feed water the
replacement frequency should be annually
with acid washed, neutralized, and rinsed
media. During media change the interior
of the activated carbon vessel should be
inspected and washed with a 100 ppm solution of sodium hypochlorite.
❖ Inlet and outlet distributors should be
inspected during activated carbon media
change and replaced as appropriate.
❖ Subsequent to activated carbon media
replacement an extended backwash and
rinse-to-drain should be conducted to remove any activated carbon “fines”.
❖ Annual calibration of feed water and
product water pressure gauges shall be
• Post Activated Carbon Unit Inline
Ultraviolet Sanitization Unit
An inline ultraviolet sanitization unit
(253.7 nanometer wave length) should be
positioned downstream of the activated
carbon unit to provide total viable bacteria
reduction from the water purification unit
operation with the highest product water
bacteria level. The unit will reduce total
viable bacteria by a factor of 10X to 100X if
properly maintained, as follows:
❖ Replace ultraviolet lamps, quartz
sleeves, and 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,
excellent bacteria destruction can be
achieved with semiannual replacement.
❖ 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
❖ If “plastic” compression nuts are used
for quartz sleeve seals, replace every
❖ Retain at least two spare compression
nuts, O-rings, lamps, quartz.
• Final Pretreatment Section Cartridge
Particulate filters are generally installed
directly upstream of the reverse osmosis unit.
Since the Ion Removal Section utilizes recirculation with continuous flow (make-up or
recirculating) around a “Break Tank”, the RO
prefilter is positioned as the final component
in the Pretreatment Section. The following
maintenance program should be considered:
❖Replace cartridge filter every 1-2 weeks.
Filter cartridges should be selected such
that a particulate removal rating (? 5 microns) with adequate particulate retention
capability for this short time period is
achieved. The brief replacement frequency
is based on bacteria control considerations.
The large surface area and partial bacteria
retentive properties provide a location for
accumulation and proliferation of bacteria.
❖ Inspect removed filters to verify the
absence of ion exchange resin “fines”, activated carbon “fines”, and excessive microbial growth (slippery surface).
❖ Annual calibration of feed water and
product water pressure gauges should be
❖ Periodic cycling of the vent valve on
the particulate removal filter housing
(daily) should be performed to remove
any accumulated air that will reduce the
effective cartridge filtration area.
❖ The cartridge filtration system and all
other components in the Pretreatment
Section (with the exception of the activated carbon units) should be chemically
sanitized with a 100-200 ppm solution of
sodium hypochlorite annually. Sanitization
should include a minimum “soak” period
of 2 hours.
❖ Replace cartridge filter housing “
bell-to-base” gasket annually.
PROGRAM – ION REMOVAL AND
A Process Flow Diagram for an Ion
Removal and Polishing System is shown
in Figure B. The diagram includes sample
valves, discussed later in this article. Both
components and arrangement of components
in the Ion Removal and Polishing Section may
vary with sanitization preference. Figure B
depicts a chemically sanitized system with
continuous recirculating capability.
• Reverse Osmosis Break Tank
The RO Break Tank provides a location
for feed from the upstream Pretreatment
Section, with air break, a location for recirculation of Ion Removal and Polishing
System recirculation flow when make-up to
the Purified Water Storage System is not required, a location for recirculation of waste
water from the continuous electrodeionization system, and a location for introduction
Figure C: Storage, Ozonation & Distribution Section
Destruct Ultraviolet Unit