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Operation and Maintenance Manual for

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SYSTEM MAINTENANCE LC <strong>Manual</strong> 11/02 Rev. 3<br />

It is important that the sanitization chemical contact all the piping<br />

within the RO system<br />

c. The outlet of the booster pump is connected to the feed of the RO<br />

system. This connection should be made prior to the prefilter<br />

housing.<br />

d. The booster pump is turned on <strong>and</strong> the RO is run in the normal<br />

operating mode <strong>for</strong> 30 to 60 minutes.<br />

CAUTION Monitor the solution temperature during recirculation. Do not<br />

allow the temperature to exceed 25° C (77° F).<br />

e. The booster pump <strong>and</strong> the RO system are shut down <strong>and</strong> the<br />

sanitant is allowed to sit in the system (optional).<br />

f. The RO is switched back to the normal feed source <strong>and</strong> run in the<br />

normal operating mode with the product diverted to drain until all<br />

residual sanitization chemicals are flushed from the system.<br />

g. The tank <strong>and</strong> booster pump are drained <strong>and</strong> flushed with clean<br />

water.<br />

h. A new prefilter is installed in the system prefilter housing.<br />

2. Continuous Injection Method<br />

In this method of sanitization, an accessory chemical feed system injects<br />

concentrated sanitant into the feed line while the RO is operating at<br />

normal flow <strong>and</strong> pressure. Both the product <strong>and</strong> reject streams are sent<br />

directly to drain.<br />

The continuous injection method is most typically used to sanitize with<br />

hydrogen peroxide. It may be used with peracetic acid if an appropriately<br />

sized chemical feed system is available <strong>for</strong> the typical 1:100 dilution ratio.<br />

It is not practical <strong>for</strong> <strong>for</strong>maldehyde sanitization because the dilution ratio<br />

used <strong>for</strong> <strong>for</strong>maldehyde (1:10 to 1:20) would require the use of a large<br />

chemical feed pump. The advantages of the continuous injection method<br />

are minimal chemical h<strong>and</strong>ling <strong>and</strong> minimal dead legs in the system<br />

piping. One disadvantage is the relatively high chemical consumption.<br />

The basic steps <strong>for</strong> continuous injection sanitization are as follows:<br />

a. An accessory chemical feed system is connected to the feed<br />

piping of the system, typically at the system inlet sample valve.<br />

b. Reject <strong>and</strong> product lines from the RO are diverted to drain. Do not<br />

use the cleaning ports on the RO system to make these<br />

connections. It is important that the sanitization chemical contact<br />

all the piping within the RO system.<br />

c. The system is operated at normal flow <strong>and</strong> pressure.<br />

4-4 USFilter

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