VI.
RO CLEANING & SANITIZATION PROCEDURES
Page - 35
Chemicals Used to Clean Organic Fouling
When foulants are suspected to be organic in nature, an alkaline based cleaner
is recommended. For general purpose cleaning of these organics, ARGO IPA
411 Caustic Cleaning Compound is recommended. This compound contains
detergent builders, chelating agents and pH buffer specifically designed to
remove organics, silt and other particulate deposits. It is provided in a dry
powder form (45 lbs containers) and can be ordered from U.S. Filter under Part
Number AGIPA411. This cleaner is intended to be mixed with Reverse
Osmosis permeate grade water at 2 lbs cleaning chemical per 10 gallons of
water. This formula will provide a cleaning solution with a weight
concentration of 3 % and a pH of approximately 10.
NOTE
If both inorganic foulant and organic foulant cleaners are to be used, the
inorganic foulant cleaner should be utilized first and a thorough rinsing of
the membranes should be completed prior to cleaning with organic foulant
chemical cleaner.
4)
Cleaning Connections
There are cleaning connections on the feed, reject, and product lines of each
stage that has multiple pressure vessels piped in parallel. Each group of
pressure vessels, of equal diameter, that have the same quantity of vessels as
the stage before it, are cleaned with the stage before it. For example, the
P43XX09 unit has a 1:1:1 array structure. This means that one vessel feeds
one vessel that feeds one vessel. This array structure can be cleaned as one
group. The P43XX12 has a 2:1:1 array structure. This means that two vessels
feed one vessel. This array structure must be cleaned as two groups. The first
stage has two vessels (two times the flow rate of the second stage (one vessel).
This is true because the flow rate required for cleaning is fixed by the diameter
of the vessels and the number of vessels in parallel.
The cleaning connections utilized on Pharmaceutical RO units are swing out
type cleaning connections. One end of an elbow (connected by tri-clamp or
victaulic connections) used for process flow is disconnected and rotated out for
use as a cleaning connection. This swing elbow connection has two
advantages over the conventional tee type connection. First, the connection is
used for service and cleaning to avoid a stagnant area during service. This is
especially important on the product line. Second, the flow and pressure of the
cleaning process is totally isolated from stages that are not being cleaned. This
isolation provides security in that only the affected stages are subjected to
exposure to the cleaning solutions.