CONCLUSIONS
Removal efficiencies for small fish processing were similar to those for large
salmon processing except for nutrients. Higher removal efficiencies for
nitrogen and lower removal efficiencies for phosphorus during large fish
processing were the result of longer retention times and over aeration which
may have caused some denitrification and phosphorus release in the aeration
chamber.
Pilot plant removal efficiencies were similar for BOD, COD, TKN and ammonia,
but higher for solids, grease/oil, and phosphorus. Shorter retention time and
reduced aeration is the suspected cause, but more data is needed to confirm
this result.
During long periods of processing plant shutdown, addition of fish food was
found to maintain performance of the wastewater treatment system.
The treatment system is capable of producing an effluent which meets the EPA
effluent limitations in terms of BOD, SS and grease/oil.