Conceptual design of a
microalgae-based recirculating oyster and shrimp system
J.-K. Wang-2003
Aquaculture Engineering, 28(1-2): 37-46
Abstract:
The need to reduce water consumption in aquaculture
has long been recognized and a great deal of research effort has been
directed toward the development of recirculating systems. Unfortunately,
current research and development in aquaculture water re-use is largely
devoted to bacteria-based systems, while microalgae-based water re-use
system development has been neglected. That a large body of knowledge is
available on bacteria-based wastewater treatment has no doubt contributed to
this reality. However, a bacterial component in a water re-use system
dedicates itself entirely to excessive nutrient removal and the required
capital and operational expenses are cost items that contribute to the
scarcity of commercial successes of such systems. In contrast, a
microalgae-based water re-use system produces microalgae that can be used to
produce a second crop, such as bivalve seed or Artemia, which can be
sold to generate income. The main difficulty encountered in the development
of a microalgae-based water re-use system has always been the inability to
maintain the desired algal species in an open system. The University of
Hawaii has solved this problem. The breakthrough in marine diatom production
technology allows us to turn our attention to the development of a water
re-use system where the `effluent' becomes a valuable resource. An
integrated shrimp/algae/oyster production system reduces water consumption
and turns effluent `waste' into a profit center while taking advantage of
the antibacterial properties of the marine diatom to control bacterial
diseases. The reduction of pathogenic bacteria is likely to also reduce the
susceptibility of the shrimp to viral disease. This paper describes the
design of a microalgae-based recirculating system that produces oyster and
shrimp using the marine diatom Chaetoceros as the intermediary media
to remove the excessive nutrients from the shrimp production and to serve as
feed for the oysters.
(Molecular Biosciences and Bioengineering Department, National Academy of
Engineering, University of Hawaii, 1955 East–West Road, #218, Honolulu, HI
96822, USA, e-mail: jawkai@hawaii.edu)