Dp. Middaugh et al., FIELD-SCALE TESTING OF A 2-STAGE BIOREACTOR FOR REMOVAL OF CREOSOTE AND PENTACHLOROPHENOL FROM GROUND-WATER - CHEMICAL AND BIOLOGICAL ASSESSMENT, Archives of environmental contamination and toxicology, 26(3), 1994, pp. 320-328
A two-stage, field-scale bioreactor system was used to determine the e
fficacy of bioremediation of creosote- and pentachlorophenol (PCP)-con
taminated ground water at the abandoned American Creosote Works (ACW)
site in Pensacola, Florida. In separate 15-day runs of the field-scale
(454L) system, bioreactor performance in the presence of specially-se
lected microbial inoculants was compared to that observed using non-sp
ecific biomass. In the first run, Bioreactor #1 was amended with nutri
ents, surfactants and microorganisms (strains CRE 1-13) that were isol
ated from soil at ACW and selectively cultured for their ability to bi
odegrade monitored creosote constituents. After 4 days of organism acc
limation and degradation of organic contaminants, the batch system was
converted to a flow-through regime. Effluent was transferred to Biore
actor #2 where Pseudomonas paucimobilis strain EPA 505 and Pseudomonas
sp. strain SR 3 were introduced. A second 15-day bioreactor run was c
onducted using indigenous bacteria and microorganisms from a waste wat
er treatment facility that was designed to treat effluents containing
PAHs and phenolics. Bioreactor performance was evaluated by chemical a
nalysis of feed water initially pumped into Bioreactor #1 and clarifie
d effluent from Bioreactor #2. These materials were also tested for to
xic/teratogenic responses with developing embryonic Menidia beryllina,
with Microtox(R) 5-min EC50 tests, and with Ceriodaphnia dubia 48-h L
C50 tests. Results obtained with specialty organisms in the first run
of the field-scale bioreactor showed that, on average, 70.6% of polycy
clic aromatic hydrocarbons (PAHs) and heterocycles were degraded. Only
36.9% of the pentachlorophenol (PCP) present was biodegraded, apparen
tly because of low cell counts and incomplete induction of Pseudomonas
sp. strain SR 3. A concomitant 67- to 74-fold decrease in toxicity wa
s measured in Microtox(R) 5-min EC50 and Ceriodaphnia 48-h LC50 values
, respectively. No reduction in toxicity/teratogenicity was measurable
in tests with embryonic M. beryllina. In the second 15-day run of the
bioreactor, microorganisms from an industrial waste water treatment f
acility averaged 51.0% biodegradation of PAHs and heterocycles. Degrad
ation of PCP was 81.0%, a value substantially higher than in the first
run. An 87-fold reduction in toxicity was measured with the Microtox(
R) 5-min EC50, but only a 2.9-fold reduction in acute toxicity was mea
sured in the Ceriodaphnia 48-L LC50 test. In the second bioreactor run
, samples taken from Bioreactors #1 and #2 indicated reduced embryo to
xicity/teratogenicity. At the 1% test concentration most embryos devel
oped normally and hatched. Larvae were also normal.