Biology Reference
In-Depth Information
friendly preventive and bioremediation methods of improving effl uent
water quality prior to discharge into receiving waters of sensitive areas
are the priority (Jones et al., 2001). Therefore, regulatory agencies have
developed standards and criteria for the aquaculture industry concerning
effl uent disposal (Kinne et al., 2001).
Similarly, fi sh and shrimp processing
industry generate large amounts of wastes that generally account for
> 50% of the live weight. Major by-products generated through processing
include visceral wastes, scales, waste (wash) water, fi lling wastes (head,
frame bones, skins and fi ns), air bladders, body/head shell wastes,
calcareous shells, etc. These wastes, unless undergoing bioremediation
can cause serious environmental problems in term of obnoxious odour
and emission of toxic gas like ammonia, hydrogen sulphide, etc. In this
context, disease management, productivity, good processing practices
and environment protection are the four key factors for successful and
sustainable aquaculture. The present chapter presents an overview of the
principles and applications of bio-/microbial-remediation in addressing
the waste management of fi sh and shrimp culture systems and processing
industry wastes.
BIOREMEDIATION
The current approach to improving water quality in aquaculture as
well as detoxifying the fi sh and shrimp processing industry wastes is
by bioremediation. Bioremediation is a general concept that includes
all those processes and actions that take place in order to bio-transform
an environment, already altered by contaminants, to its original status.
Although the processes that can be used in order to achieve the desirable
results vary, they still have the same principles; the use of microorganisms
or their enzymes
,
that are either indigenous and are stimulated by the
addition of nutrients or optimization of conditions, or are seeded into
the medium (Thassitou and Arvanitoyannis, 2001). Bioremediation
is recognized as an inexpensive, effective, and environmentally safe
technology, which offers new and innovative ways to clean up hazardous
wastes.
When microorganisms and/or their products are used as additives to
improve water quality, they are referred to as bio(microbial)-remediators
or microbial remediating agents (Moriaty, 1998). They result in a lower
accumulation of slime or organic matter at the bottom of the pond , better
penetration of oxygen into the sediment and a generally better environment
for the farmed stock (Rao and Karunasagar, 2000). The isolation and
development of indigenous bacteria are required for successful microbial
remediation (Austin and Brunt, 2009). A successful microbial remediation
process in the aquaculture system involves:
