FISHERY BULLETIN: VOL. 74, NO. 4 



By calculation, the COD of the particulate 

 matter and its percentage contribution to the total 

 COD are: 



underflow of Dorr-Oliver 0.4-mm screen and an- 

 alyzed (Table 3). Average values by analysis are as 

 follows: 



COD of NFR (a - c) = 1,124 mg/liter 42.5% 



COD of SS (a - b) = 305 mg/liter 11.5% 



COD of Sus. Sol. 



[(a - c) - (a - b)] = 819 mg/liter 31.0% 



Some figures were also collected on the concen- 

 tration of residues by direct analysis and are 

 included in the table to illustrate the problems 

 associated with monitoring plants that process 

 with salt water. Residue values were not deter- 

 mined by calculation because of the high and 

 variable salt content. It is questionable that 

 meaningful data for NFR can be obtained because 

 of errors that can occur when the salt values of 

 about 25,000 mg/liter are subtracted from the 

 mean TR values of about 27,000 mg/liter. 



Study 3— Snow Crab: Analyses of effluents from a 

 plant processing both meats and sections in fresh 

 water. 



Over a 2-wk period in February 1974, six sam- 

 ples of waste effluent from a plant processing snow 

 crab using fresh water were taken from the 



a. COD, screened effluent 



b. COD, center of Imhoff cone 



c. COD, filtrate from NFR test 



d. Total residue (TR) 



e. Filterable residue (FR) 



f. Settleable solids (SS) 



g. Nonfilterable residue (NFR) 



1,426 mg/liter 

 1,332 mg/liter 



824 mg/liter 



1,393 mg/liter 



1,086 mg/liter 



4.2 ml/liter 



277 mg/liter 



By calculation, the mean values for COD of the 

 particulate matter and its percentage contribution 

 to the total were: 



COD of NFR (a - c) = 602 mg/liter 42.2% 



COD of SS (a - b) = 94 mg/liter 6.6% 

 COD of Sus. Sol. 



[(a - c) - (a - b)] = 503 mg/liter 42.2% 



By calculation, the mean value for NFR is: 

 (d - e) = 307 mg/liter. 



Study 4— Salmon: Analyses of effluents from a plant 

 processing canned salmon. 



During the summer of 1974, ten samples of 



Table 3.— Analyses of snow crab waste effluents from a plant processing both meats and 

 sections in fresh water. All values are in milligrams per liter e.xcept SS in milliliters per liter. 



Table 4.- Analyses of salmon waste effluents from a plant processing canned salmon. All values are in milligrams 



per liter. 



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