COLLINS and TENNEY: FISHERY WASTE EFFLUENTS 



a. COD, screened effluent 



b. COD, center of Imhoff cone 



c. COD, filtrate of NFR test 



3,257 mg/liter 

 3,043 mg/liter 

 1,616 mg/liter 



By calculation, the COD of the particulate 

 matter and its percentage contribution to the total 

 COD are: 



COD of NFR (a - c) = 1,641 mg/liter 50.4% 

 COD of SS by weight 



(a - b) = 214 mg/liter 6.6% 

 COD of Sus. Sol. 



[(a - c) - (a - b)] = 1,426 mg/liter 43.8% 



By analysis and calculation, data were also 

 obtained for the means of other residue tests: 



By analysis: 



d. Total residue (TR) 



e. Filterable residue (FR) 



f. Settleable solids (SS) 



g. Nonfilterable residue (NFR) 



2,381 mg/liter 



1,577 mg/liter 



5.6 ml/liter 



769 mg/liter 



By weight, the FR was 66.3% of the TR, but the 

 COD of the FR was only 49.6% of the total COD. 

 The NFR, however, contributed only 33.7% to the 

 TR by weight but contributed 50.4% as COD. 



The standard deviations (SD) in Table 1 show 

 relatively large values in agreement with practical 

 experience. The higher average concentration and 

 lower SD for the NFR determined by difference 

 suggests that this is a better method for deter- 

 mining the concentration of NFR than is the 

 direct analysis. 



Study 2— Shrimp: Analyses of effluents from a 

 shrimp plant processing with salt water and 

 mechanical peelers (Models A and PCA). 



Ten samples of waste effluent were taken from 

 the underflow of the 0.7-mm Dorr-Oliver screen. 

 The individual results are given in Table 2, and the 

 average analytical data are as follows: 



By calculation: NFR, i.e., (d 

 mg/liter. 



e) or TR - FR = 804 



a. COD, screened effluent 



b. COD, center of Imhoff cone 



c. COD, filtrate from NFR test 



d. Settleable solids (SS) 



e. Nonfilterable residue (NFR) 



2,643 mg/liter 



2,338 mg/liter 



1,519 mg/liter 



7.8 ml/liter 



684 mg/liter 



Table 1. -Analyses of shrimp waste effluents from a plant processing with fresh water and 

 mechanical peelers (Model A). All values are in milligrams per liter except SS in milliliters per 

 liter. 



Table 2.-Analyses of shrimp waste effluents from a plant processing with salt water and 

 mechanical peelers (Models A and PCA). All values are in milligrams per liter except SS in 

 milliliters per liter. 



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