REMOVAL OF NITRATE FROM INDUSTRIAL WASTEWATERS IN A PILOT-PLANT BY NITRATE-TOLERANT KLEBSIELLA-OXYTOCA CECT-4460 AND ARTHROBACTER-GLOBIFORMIS CECT-4500
G. Pinar et al., REMOVAL OF NITRATE FROM INDUSTRIAL WASTEWATERS IN A PILOT-PLANT BY NITRATE-TOLERANT KLEBSIELLA-OXYTOCA CECT-4460 AND ARTHROBACTER-GLOBIFORMIS CECT-4500, Biotechnology and bioengineering, 58(5), 1998, pp. 510-514
Two strains, a gram-negative bacterium Klebsiella oxytoca CECT 4460 an
d a gram-positive, mycelium-forming bacterium Arthrobacter globiformis
CECT 4500, tolerant to up to 1 M nitrate, were isolated from the grou
nds of a munitions factory. Under strict aerobic conditions and with a
ppropriate C-sources, growth of these bacteria took place when the nit
rate concentration in the medium was below 150 mM. Optimal growth cond
itions regarding the culture medium composition for the biological rem
oval of nitrate were established in batch cultures. Then, the system w
as scaled up to a 40-L pilot plant and operated under continuous condi
tions in a factory with direct waste streams from dinitroethylene glyc
ol production after appropriate dilution with nontreated groundwaters.
The level of nitrate in the effluent was below 0.5% of the initial N-
load. Nitrite and ammonium were undetectable and the level of the C-so
urce in the effluent was below 50 mg per L. On the basis of these resu
lts, we conclude that the system worked on site satisfactorily. (C) 19
98 John Wiley & Sons, Inc.