Biology Reference
In-Depth Information
reducing COD and nitrifying the ammonia and organic nitrogen for its
further removal at the denitrifi cation stage. Under operating conditions,
ammonia accumulation in the aerobic reactor occurs, inhibiting nitrite-
oxidizing bacteria. Specifi c removal rates of COD (up to 1.5 g COD/g VSS
(volatile soluble solids)/d) and TKN (total kjeldahl nitrogen) (up to 0.25
g N/g VSS/d) were obtained. The effect of nitrogen loading rate (NLR)
on ammonia conversion was studied. A linear relationship was found
between NLR and ammonia oxidation rate up to NLR of 0.6 g-TKN/L/d.
Percentages of COD removal ranged from 95% to 60% and the nitrifi cation
percentages from 65% to 20% (Garrido et al., 1998).
Fishmeal waste water (FWW) and starch waste water (SWW), without
amendment of nutrients, were investigated for lactic acid production
using two strains of
Rhizopus oryzae
.
R. oryaze
AS 3.254 could use FWW
and SWW simultaneously for lactic acid production and fungal growth
while
R. oryzae
3.41 only utilized this complex for fungal growth. For
R.
oryzae
AS 3.254, the optimal C/N for lactic acid production was 100:1.
R. oryzae
3.41 could produce lactic acid by use of glucose and FWW
and the optimal C/N ratio was 124. Both fungal strains showed higher
biomass production at lower C/N ratio. The direct lactic acid production
from SWW and FWW by
R.
orazae
AS 3.254 was characterized by starch
hydrolysis, accumulation of reducing sugars, COD and nitrogen removal,
and production of lactic acid and fungal biomass. Starch hydrolysis could
arrive at 1.23 g/l/h while COD and nitrogen removal were 96.2% and
89.4%, respectively at fermentation time 88 h. The highest lactic acid yield
was 0.674 g COD/g COD based on the equivalent COD of SWW and FWW
associated with 2.65 g/l fungal biomass at fermentation time 72 h while
the maximum productivity 0.783 g/l/h was obtained at fermentation time
40 h (Huang et al., 2008).
CONCLUSIONS
Minimization and enforced reduction of pollutant loads from aquatic
animal production and processing facilities are increasingly demanded
by various segments of the public and the regulatory community.
Environmental rules and laws will continue expanding at all levels of
government, requiring increased public and private expenditures. Among
the challenges facing the fi shery industries are new restrictions on the
use of cleaners such as chlorine, the disposal of solid waste, the use of
packaging materials, and the discharge of wastewaters (Martin, 1999).
The Environmental Protection Agency estimates that aquaculture
industry cost will double in the next 10 yr as a result of strict enforcement
of bioremediation of these pollutants. The uses of microorganisms
as bioremediating agents in pond culture and in other devices such as
