Odor Control For Fish Drying
Odor Control For Fish Drying
(OP)
Need some advice regarding operation of two-stage packed tower scrubber systems used to control odorous emissions from a fish-waste drying facility. The facility dries fish using rotary dryers into a fish-protein powder.
Emissions from the rotary fish dryers include ammonia, hydrogen sulfide, various amines and mercaptans. Exhaust from each dryer first passes through a cyclone and then through a heat exchanger where the temperature of the exhaust is dropped to less than 100 F. The exhaust is then routed through a two-stage packed tower scrubber system. In the first stage, a sulfuric acid solution is used and the pH is maintained at about 2.5. Oxidation-reduction potential (ORP) is maintained at 600-mv using chlorine dioxide as an oxidant. In the second stage, sodium hydroxide is used to maintain the pH at 10.5, and ORP is maintained at 650 mv, again using chlorine dioxide.
Testing of the scrubber systems showed that they are achieving 98% control of trimethyl amine and hydrogen sulfide. However, there are still emissions that are causing odor complaints. Odors are described as “fishy” and sometimes “chlorine + fishy.”
Does anyone have any suggestions regarding improving operation of our scrubbers? Has anyone else had better luck with different scrubber chemistry? Is there any drawback to using an oxidant in the first stage scrubber?
Thanks
ORCAA Man
Emissions from the rotary fish dryers include ammonia, hydrogen sulfide, various amines and mercaptans. Exhaust from each dryer first passes through a cyclone and then through a heat exchanger where the temperature of the exhaust is dropped to less than 100 F. The exhaust is then routed through a two-stage packed tower scrubber system. In the first stage, a sulfuric acid solution is used and the pH is maintained at about 2.5. Oxidation-reduction potential (ORP) is maintained at 600-mv using chlorine dioxide as an oxidant. In the second stage, sodium hydroxide is used to maintain the pH at 10.5, and ORP is maintained at 650 mv, again using chlorine dioxide.
Testing of the scrubber systems showed that they are achieving 98% control of trimethyl amine and hydrogen sulfide. However, there are still emissions that are causing odor complaints. Odors are described as “fishy” and sometimes “chlorine + fishy.”
Does anyone have any suggestions regarding improving operation of our scrubbers? Has anyone else had better luck with different scrubber chemistry? Is there any drawback to using an oxidant in the first stage scrubber?
Thanks
ORCAA Man





RE: Odor Control For Fish Drying
RE: Odor Control For Fish Drying
The second stage is good.
What are flowrate and concentration at the outlet of your second stage.
May be it is possible to install a biofilter.
JPPMJ
RE: Odor Control For Fish Drying
You could build a trial unit for little money. Almost any sturdy grass could be used as the plant material.
RE: Odor Control For Fish Drying
Seán
www.expertise-limited.co.uk