The salt doesn't come from the stickwater since this is the water within the fish. It normally comes from ocean water used for refrigeration if that comes in with the fish or in the case of So. America from the pumpwater used to unload the fish. Almost all fishmeal is wholemeal, that is, contains all the concentrated solubles added back. The quality of the meal depends on the quality of the fish and the quality of the stickwater, if it is allowed to decompose then it will reduce the quality of the fishmeal.
If salt is the only issue then it is a matter of looking at the process to see where the salt is coming from. For example, some plants receive only trimmings and sometimes included with the trimmings are spoiled salted fish. In any event, it is, in your case (Alaska), most likely due to adding Pacific Ocean water.
One also has to weigh the eventual cost of treating stickwater if it is discharged or being fined vs the cost of adding the evaporation equipment and getting something back. Not sure what a sewer system would charge to receive stickwater in a treatment plant. One has to assume that sooner or later the discharge overboard is going to be stopped.
Anyway, that is my opinion.
Regards
Tony Bimbo
----- Original Message -----
From: Greg Peters
To: Anthony P. Bimbo ; seafood@ucdavis.edu
Sent: Tuesday, August 13, 2002 6:15 PM
Subject: Re: Stickwater, COD, BOD
Sorry,
But you're not exactly correct. The value of meal produced from stickwater is not as good as traditional meal. The salt content is too high so either additional capital expense needs to be added for salt removal or the meal is sold at a decreased value. Either way, the payback is substantially longer than a year and that is if you have the capital to invest in the first place.
BOD for stickwater is usually between 30,000 and 50,000 mg/l
COD is usually 70,000 to 115,000 mg/l
TSS is usually 20,000 to 30,000 mg/l
Greg Peters
Alyeska Seafoods, Inc.
"Anthony P. Bimbo" wrote:
<?color><?param 0100,0100,0100> Mauricio: Try the link below. The EU has been working on this for some time and fish processing is part of the work. Using BOD and COD for stickwater is a non-starter since the solids content is around 8% and when converted to fishmeal is an enormous amount of yield to lose. With prices where they are now, a stickwater plant pays for itself in about a year. The environmental load from discharged stickwater should not be tolerated and the cost to treat the BOD and COD could be equivalent to a medium to large city. Hope this helps. You can read and download the BREF from the website, either via the "Utilities and members workspace" page by clicking on "Direct Access to
Public Area" or via the "Activities" page.
The address of the website is http://eippcb.jrc.es.
----- Original Message -----
From: Mauricio Gonzalez
To: seafood@ucdavis.edu
Sent: Tuesday, August 13, 2002 4:19 PM
Subject: Stickwater, COD, BOD
Hello Everyone,
Does anybody have information about suspended solids in stickwater v/s COD and BOD (herring and shrimp fishmeal processing plants)?
Thanks in advance,
Mauricio
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MAURICIO GONZALEZ
Ph.D. Engineering Sciences
Docteur en Sciences de l'Ingénierie
Doctor en Ciencias de la Ingeniería
Marine Products Research and Development Center Inc
Centre de Recherche et de Développement des Produits Marins Inc
Centro de Investigación y Desarrollo de Productos Marinos Inc
218 J.D.Gauthier Boulevard, 5th floor
218, boulevard J.-D.-Gauthier, 5e étage
218, bulevar J.-D.-Gauthier, 5to piso
E8S 1P6, Shippagan
New Brunswick, Canada
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