9420.pdf

7.2 Processing Technology
Treatment
7.2.1 General
Improvements, Water Conservation and Wastewater
The following section is a general discussion of some of the factors which have or may
have an impact on the cost of implementing changes to reduce the contaminant load
being discharged from fish processing plants (i.e. in-house modifications as well as endof-pipe
treatment). The discussion is presented in general form, as a wide range of
conditions exist. In general, the factors that need to be considered are as follows:
plant profitability
type of process
Iabour costs;
water rates;
discharge fees;
waste disposal requirements and options.
7.2.2 Plant Profitability
As outlined in Section 7.1, plant profitability cannot be addressed in this document on a
plant-specific basis. The discussion presented in Section 7.1 should be reviewed to
determine the overall profitability of the B.C. fish processing industry.
7.2.3 Type of Process
The species of fish handled, and the type of processing taking place at a fish processing
plant, greatly affect the nature and quality of the wastewater generated. For example,
herring processing generally results in wastewater with a higher dissolved BOD fraction
than salmon canning, with the result that employing finer screens would not be as
beneficial for herring processing as for salmon canning wastewaters. Similarly, bleeding
farm salmon is believed to result in a higher dissolved BOD fraction than salmon canning
due to the high dissolved BOD of blood. The species and process specific wastewater
characteristics can not be changed unless new operating methods can be developed
which result in comparable or superior product quality.
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