Operating the trickling filter with refinery WW

These facilities are economically attractive despite the costly plastics because they are simple, there is often no secondary settler and, theoretically, no frequent measurement. In practice however, difficulties in operating some of them have caused the bed mass to become clogged in the space of a few months. As a result, the bed materia has had to be cleaned either in situ or after removal from the unit. 

These malfunctions occurred mainly with random fill materials that tend to compact dramatically (10 to 20%) in a well-nigh irreversible process after a few months operating time. 

The use of the random fill material technique in refineries must therefore be contemplated only with a number of modifications  

Ordered fill materials are a less sensitive but more expensive alternative. 

Here the contact mass is made up of grains several millimeters in size sand, anthracite, slags or lighter materials. 

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