I can tell you the process we have recently been involved in to obtain
a permit to operate for a fish meal processing plant here on the west
coast (South Africa).
The plan included the installation of a bio-filter which was "spiked"
with the correct type of organism to break down some of the various
compounds found in the emissions. This semi-cleaned smoke is then
passed through a scrubbing tower into which we feed the product
"Oxine" (an oxidative product) which we use to remove the final
odours. The resultant emissions are not completely with out smell, but
no "off", "fishy" or "offensive" odours can be detected. The results
speak for themselves - almost no complaints from the public.
The effective use of the scrubbing tower is the key in my opinion -
with out the chemical additive we now use, the complaints were many.
In one particular factory, with only minor modifications to the
existing equipment to accommodate the use of this additive, the
complaints from the community have all but ceased. When this factory
ran out of stock (Oxine), but continued processing - well the
complaints started rolling in again.
I do not recommend one product above another, but perhaps your
approach should be as follows :
Ensure that as far as possible, all odours are collected at point of
generation. Try reducing the output of "off" odours by maintaining
good temperature control in the process.
Initial treatment can include a bio-filter, but be careful of the air
output volumes involved - this might become impractical due to size
requirements.
Final treatment using an oxidizing agent - again be careful of the air
volumes involved.
I hope this might spark some ideas and be of some help.
Regards
Paul Stewrat
Key Account Manager
CSIR FOODTEK FIRI
Tel : +27-21-6899341
Fax : +27-21-6866116