Biology Reference
In-Depth Information
Almost all of the remaining world fi sh production of 33.3 million tonnes
(23.2%) was destined for non-food products mainly for the manufacture of
fi shmeal and fi sh oil ( Table 8.3 ) .
The fi sh processing industry is very widespread and quite varied in terms
of types of operation, scales of production and outputs. The species of fi sh
processed include cod, tuna, herring, mackerel, pollock, hake, haddock,
salmon, anchovy, pilchards and tropical fi sh.
Fish Cannery Waste Water
Water is used for treating and transporting fi sh, for cleaning equipment
and work areas, and for fl uming offal and blood during the canning
process. Waste water is most often not utilized and is dumped directly
or after being clarifi ed through activated sludge, into the external
environment ( Fig. 8.2 ) . The discharge of fi sh drainage water into rivers
or coastal waters often causes water pollution and lead to problems such
as red tide. However, the use of microorganisms in the activated sludge
for drainage clarifi cation produces a secondary waste of cell biomass that
must be buried in landfi lls. Therefore, drainage remediation should utilize
microorganisms carefully selected so that the resulting biomass can be
used for other industrial objectives such as feeds in aquaculture and an
effi cient recycling system can be established.
A novel technique for managing fi sh processing wastewater by
cultivating proteolytic yeast, Candida rugopelliculosa , as a possible diet of
the rotifer, Brachionus plicatilis was studied (Lim et al., 2003). It was feasible
to use Alaska Pollack processing wastewater as a growth medium for
C. rugopelliculosa , which was stimulatory for growth of the rotifer by 18.3%
over the commercial diet of Saccharomyces cerevisiae . Maximum growth of
C. rugopelliculosa and reduction of infl uent soluble chemical oxygen demand
(SCOD) concentration were 6.09 ± 0.04 x 10 6 cells/l and 70.0%, respectively
at 6.3 h hydraulic retention time (HRT). The maximum microbial growth
rates (Mmax); half saturation coeffi cient (Ks); microbial yield coeffi cient
(Y), and microbial decay rate coeffi cient (kd) were determined to be
0.82 ± 0.22/h, 690 ± 220mg SCOD/l, (1.39 ± 0.22)x10 4 cells/mg SCOD and
0.06 ± 0.01/h, respectively.
Several yeasts were also isolated from a drainage canal in a Japanese
fi sh processing factory. They were characterized by the decomposition
of organics such as protein and reducing sugars, their growth in the
wastewater, the decrease in total organic carbon (TOC), and taxonomy.
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