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TABLE OF CONTENTS Pages Symposium 1 - the National Sea ...

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interrupted during backwashing. Backwash water, which accumulates in <strong>the</strong> charge<br />

chamber, is completely displaced by new air entering <strong>the</strong> pneumatic charge chamber. The<br />

trigger rapidly releases <strong>the</strong> air in <strong>the</strong> pneumatic charge chamber and <strong>the</strong> dirty wash waters<br />

drop through <strong>the</strong> chute. The trigger is <strong>the</strong>n closed and ano<strong>the</strong>r filtration cycle initiated.<br />

Sludge is generally allowed to accumulate before it is removed through <strong>the</strong> sludge line (3).<br />

Consolidation of sludge is generally rapid, and sludge thickening and compaction usually<br />

control <strong>the</strong> maximum length of time between removal. In fish systems, problems can<br />

occur with sludge flow after a week or two.<br />

Figure 2. Backwashing mode of <strong>the</strong> MRBF.<br />

Significance<br />

(1)<br />

Water Flow<br />

(6)<br />

E<br />

(7)<br />

Air<br />

The MRBF’s pneumatic backwashing feature breaks <strong>the</strong> linkage between backwashing and<br />

waterloss. This linkage has limited optimization of backwash frequencies for a number of<br />

years. This new freedom is likely to be a significant advancement on bead filter bioclarifier<br />

application in both <strong>the</strong> freshwater and saltwater aquaculture areas.<br />

Wimberly (1990) and Sastry et al. (1999) demonstrated <strong>the</strong> advantages of high frequency<br />

backwashing in gently washed formats. In both of <strong>the</strong>se studies “gently-washed” formats<br />

6<br />

(2)<br />

Patent # 5,770,080<br />

(5)<br />

C<br />

Water<br />

(4)<br />

(3)<br />

Air Flow

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