7
Biological Performance
:
Water quality conditions and planktonic communities during this evaluation were typical
of summer in the upper Chesapeake Bay. Below is a summary of live organism concentrations
in treated water upon discharge after five-day holding times, for each regulated category. More
detailed datasets for each trial are provided in Sections 6 - 9.
Live Organisms
Category
USCG/IMO
Standard
Trial 1
Trial 2
Trial 3
Trial 4
>50 µm
< 10/m
3
3,030/
m
3
20/
m
3
10/
m
3
12/
m
3
10-50
µm
< 10/ml
67/
ml
10/
ml
3/
ml
2/
ml
E. coli
< 250 cfu/100 ml
1
cfu/100 ml
1.7
cfu/100 ml
1
cfu/100 ml <1 cfu/100 ml
Enterococci
< 100 cfu/100 ml <1 cfu/100 ml <1 cfu/100
ml
<1 cfu/100
ml
<1 cfu/100 ml
Tox
V. cholerae
< 1 cfu/100 ml
NEG
NEG
NEG
NEG
NEG: Negative,
Vibrio cholerae
O1 and O139 were not present in the sample
Discharge Toxicity:
Although the BIO-SEA BWMS process does not utilize an active substance, treated
discharge water was examined for toxicity as part of one biological test trial (Trial 2). The
treated ballast water upon discharge was not acute or chronically toxic to any species tested.
There were no statistically significant survival or growth effects in any tests or on any species.
There were no statistically significant survival or growth effects in any tests or on any species
(
Isochrysis galbana
,
Cyprinodon variegatus
and
Americamysis bahia
).
The algae test with
Isochrysis galbana
,
however, exceeded the coefficient of variation (CV%) minimum of 20%
between control replicates. The final CV% was 26% and was the result of one treatment which
had very low growth with a final concentration of 2.6 x 10
6
cells per ml, compared to the other
three replicates with an average of 4.67 x 10
6
cells per ml. We believe, since the variability was
caused by one treatment, the lower growth was due to contaminated glassware (i.e. test flask).
Interestingly the two control tank samples (56 and 100%) had very similar within
treatment final densities, with CV% values of 11 and 10% respectively; while treated replicates
had very high variability with CV% values of 79 and 39% for two treatments (56 and 100%).
Despite the variability, there was no statistical difference (α=0.05) between the mean cell density
of any treatment compared to control.
Quality Assurance:
The MERC Quality Assurance (QA) Manager independently conducted a technical
systems audit (TSA), an audit of data quality (ADQ), and a Data Quality Assessment (DQA) for
the BIO-SEA BWMS evaluation. The audits were conducted in accordance with the procedures
described in EPA's
Guidance on Technical Audits and Related Assessments for Environmental
Data Operations (EPA QA/G-7)
.
There were no errors or negative findings in any QA
assessment and all data objectives were met. See Section 10 for additional details.
*
Please note that while it is not possible to display every data point collected during this set of
land-based trials, key performance data is provided below and all raw data and complete datasets
from this evaluation are available upon request.