Due to the increase of shellfish consumption in
the past decade, the derived shell from the aquacul-
tural farming and/or commercial market has become
one of the most significant wastes in Taiwan. Accord-
ing to the statistic data on the aquacultural industry,
oyster (Crassostrea gigas) and clams (Meretrix lu-
soria and Paphia undulata) are the most predominant
in Taiwan, and 200 kt of waste shells per year at
least were thus produced [1]. Most waste oys-
ter shells, however, were locally dumped into public
waters and lands without proper treatment, causing a
serious odor problem as a result of the remaining at-
tached to the shellfish. This practice apparently was
not desirable in view of the environmental odor prob-
lems. On the other hand, the waste shell is primarily-
composed of calcium carbonate crystals laid down