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903979005
[ U.S. ENVIRONMENTAL PROTECTION AGENCY
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MIDDLE ATLANTIC REGION-III 6th and Walnut Streets, Philadelphia, Pennsylvania 19106
-------
EPA 903/9-79-005
BIOCHEMICAL STUDIES
OF THE
POTOMAC ESTUARY—SUMMER 1978
-------
EPA 903/9-79-005
BIOCHEMICAL STUDIES
OF THE
POTOMAC ESTUARY—SUMMER 1978
May 1979
Joseph Lee Slayton
E. Ramona Trovato
Annapolis Field Office
Region III
U.S. Environmental Protection Agency
-------
Table of Contents
Page
Tabulation of Figures ii
Tabulation of Tables iii
I. Introduction 1
II. Conclusions 4
III. Procedures 6
IV. C30D and NOD Kinetics 1n The Potomac Estuary 8
V. Oxygen Demand of Algal Respiration and Algal Decay 19
VI. Phytoplankton Elemental Analysis/Methods of TKN 25
Digestion of Algal Samples
VII. Potomac Long-Term BOD Survey Data 28
References 35
-------
Figures
Page
No.
1. Study Area 3
2. General BOD Curve: Y * L0(l-10'kt) 8
3-4. River Samples-Oxygen Depletion Curves 10-11
5. Plot of NOD2Q vs (TKN x 4.57) 15
6. STP Effluent Samples-Oxygen Depletion Curves 17
7-9. Oxygen Depletion Curves of Algal Respiration and Decay ... 20-22
-------
Tables
Page
1. Station Locations 2
2. Thomas Graphical Determinations of RIQ. L0, and r for River CBOD's . 12
3. Thomas Graphical Determinations of k]g> L0> and r for River NOD's . . 13
4. Thomas Graphical Determinations of k-|Q, L0, and r for STP CBOD's . . 16
5. First Order Correlation Coefficients for STP NOD's 18
6. Phytoplankton Oxygen Depletion 23
7. BODs Requirements for Algal Decay and Respiration 24
8. Phytoplankton Elemental Analysis 26
9. Results from Three TKN Digestion Methods 27
-------
I. Introduction
During the summer of 1978 an intensive survey of the middle
reach of the Potomac River was undertaken by the A.P.O. (Table 1,
Figure 1). As part of this work biochemical assays were performed to:
(1) determine the carbonaceous and nitrogenous oxygen demand
rate constants for river and STP effluent samples;
(2) establish the relative contributions to the BOD5 of algal
respiration and the oxygen utilized in algal decay; and
(3) characterize the elemental composition of the phytoplankton
present and establish the relative digestion efficiencies
of several methods of algal TKN determinations.
The mention of trade names or commercial products in this report
is for illustration purposes and does not constitute endorsement or
recommendation by the U.S. Environmental Protection Agency.
-------
Table 1. Station Locations
Station Number
Station Name
RMI
Buoy Reference
P-8
P-4
1
1-A
2
3
4
5
5-A
6
7
8
8-A
9
10
10-B
11
12
13
14
15
15-A
16
Station Number
S-l
S-2
S-3
S-4
S-5
S-6
S-7
S-8
Chain Bridge
Wndy Run
Key Bridge
Memorial Bridge
14th Street Bridge
Ha ins Point
Bellevue
Woodrow Wilson Bridge
Rosier Bluff
Broad Creek
Ft. Washington
Dogue Creek
Gunston Cove
Chapman Point
Indian Head
Deep Point
Possum Point
Sandy Point
Smith Point
Maryland Point
Nanjemoy Creek
Mathias Point
Rt. 301 Bridge
Treatment Plant Name
Piscataway STP
Arlington STP
Blue Plains STP East &
Alexandria STP
Westgate STP
Hunting Creek STP
Dogue Creek STP
Pohick Creek STP
0.0
1.9
3.4
4.9
5.9
7.6
10.0
12.1
13.6
15.2
18.4
22.3
24.3
26.9
30.6
34.0
38.0
42.5
45.8
52.4
58.6
62.8
67.4
West
C "1"
FLR-23' Bell
C "87"
N "86"
FL "77"
FL "67"
R "64"
FL "59"
N "54"
R "44"
N "40"
N "30"
G "21"
N "10"
C "3"
-------
Figure 1. Study Area
Potomac Estuary
-------
II. Conclusions
(1) The carbonaceous oxygen demand of the Potomac River samples
followed first order kinetics with an average deoxygenation
constant ke = 0.12 day "^ and standard deviation = 0.03 day""*
= 0.051 day'1).
(2) The growth kinetics of river nitrification were more erratic
but in general were first order with an average ke = 0.10 day"
and standard deviation of 0.06.
(3) The CBOD5 on the average was 58% of the BODs for river samples
and therefore estimates of CBOD5 from BODs values are prone to
error unless a nitrification inhibitor is employed.
(4) The CBOD of the Potomac STP effluent samples followed first .
order kinetics with an average ke =0.16 day'1 and standard
deviation of 0.05.
(5) The NOD for the STP effluent samples had a significant lag
time resulting in poor correlation coefficients for first
order fit. This lag time was probably an artifact of the
APHA dilution method, since nitrification in the receiving
waters was immediate.
(6) The NOD2Q observed for river samples did not significantly
differ from the product of 4.57 and the TKM concentration
(4.57 x TKN).
-------
(7) In concentrated algal samples the average algal contribution
to the BOD5 was 0.027 mg BOD5/yg chlorophyll a_. The predominant
species present was the filamentous blue green algae Pseudanabaena,
(8) Phytoplankton decay represented 70% of the algal BODs and algal
respiration accounted for the remaining 30% of the five day
oxygen depletion.
(9) The average composition of the phytoplankton present in the
study area was (mg/vg):
Org C/Chlor a. = .021 ; P04/Chlor a. » .002; TKN/Chlor a_ = .005
(10) Relative to manual digestion the Technicon continuous digestor
and Technicon block digestor recovered respectively an average
of 58% and 83% of the algal TKN.
-------
III. Procedures
Biochemical Oxygen Demand: The BOD test is outlined in Standard
Methods APHA, 14th edition1. All dissolved oxygen measurements
were made with a YSI BOD probe #5720 and a YSI model 57 meter.
The BOD of river water was determined on unaltered samples. STP
effluent samples were altered by: the addition of 1 ml of stale
settled sewage (seed); sufficient sodium sulfite (NazSOs) to
dechlorinate the samples; and dilution with APHA dilution water.
Nitrification: Formula 2533 nitrification inhibitor (Hach Chemical
Co.) was dispensed directly into the BOD bottles. Two bottles
were filled with each sample—one received the inhibitor and
represented CBOD and the uninhibited bottle expressed total BOD.
The NOD was determined by difference2.
A1 gal BOD Measurements; The algae in 4 to 10 liters of sample were
concentrated by continuous centrifugation (Sharpies Continuous
Centrifuge Model T-l at 12,000 rpm and 1.5-2 liters/min). The
pellet was resuspended in 500 ml of collected supernatant. The
resultant suspension was diluted in a 300 ml BOD bottle as follows:
a. 50 ml suspension + 250 ml supernatant
b. 50 ml suspension (freeze dried) + 250 ml supernatant
c. 50 ml deionized water + 250 ml supernatant
a1. 50 ml suspension + 249ml supernatant + 1 ml seed/bottle
b1. 50 ml suspension (freeze dried) + 249ml supernatant +
1 ml seed/bottle
c1. 50 ml deionized water + 249 ml supernatant + 1 ml seed/bottle
The sample composite on September 6 consisted of approximately
2 gallons each from stations: 8; 8A; 9; 10; and 10B.
The composite of September 14 consisted of about 1/2 gallon each
from stations: 8; 8A; 9; and 10. Twenty ml volumes were used
instead of the 50 ml volumes indicated above for this composite.
Freeze Drying: Samples were freeze-dried in a Virtis model 10-100
Unitrap freeze-drier. The suspension was spread as a thin sheet
and slowly frozen to avoid foaming and to shorten drying time.
Samples required 4 to 6 hours to reach the manufacturer's specified
end point.
The freeze-dried samples were washed into BOD bottles with
supernatant from centrifugation.
Elemental Analysis:
1. Sample Preparation: Samples were stored on ice and returned to
the laboratory where 4 to 8 liters were immediately concentrated
using a Sharpies T-l Continuous Centrifuge at 12,000 rpm and
1.5-2.0 liters/min. Microscopic examination revealed no
-------
apparent morphological damage to the predominant phytoplankton
species present. The pellet was resuspended in 250 ml of
clear supernatant, which had been collected during centrifugation,
Aliquots of the suspension and the supernatant were chemically
analyzed. The supernatant values were used for blank corrections,
2. Chlorophyll a: The photosynthetic pigment from 5-20 ml of
algal suspension was retained on a 0.45y Millipore filter and
extracted into 90% acetone with grinding. The extracted
solution was centrifuged and measured spectrophotometrically3.
3. Total Organic Carbon (TOG): 10 ml of algal suspension was
diluted to 100 ml in a volumetric flask using deionized water.
A blank was run using 10 ml of supernatant river water
diluted to 100 ml in deionized water. The samples and
calibration standards were then acidified by the addition of
1 ml of 6% phosphoric acid to 25 ml and purged free of
inorganic carbon with oxygen. The total organic carbon
was then determined on a Beckman 915 TOC analyzer**.
4. Total Phosphate: 5 ml of sample and blank were diluted to
25 ml with deionized water. The sample and blank were
placed in aluminum foil covered pyrex test tubes to which
ammonium persulfate and sulfuric acid were added and auto-
el aved at 15 psi for 30 minutes. The digests were then
analyzed for total phosphate by the Technicon automated
ascorbic acid reduction method .
5. Algal Nitrogen; 5 ml of sample and blank were diluted to
25 ml with deionized water. The prepared solutions were
then analyzed for TKN by the following methods:
A. Helix: Samples and blanks were digested by a Technicon
Continuous Digestor (Helix) and analyzed by the
automated colorimetric phenolate method4.
B. Manual : Samples and blanks were manually digested
with 10 ml aliquots placed in reflux tubes and 8.0 ml
of H2S04/K2S04 digestion solution added. The tubes
were placed over flame until boiling and reflux
stopped. The contents of the tubes were washed
into a graduated cylinder with deionized water and
brought to 50 ml. The resultant digests were analyzed
using a Technicon Continuous Digestor (Helix) and
the Technicon automated colorimetric phenolate method1*.
C. Block: Samples and blanks were analyzed by a Technicon
Block Digestor BD-40 and analyzed by the salicylate/
nitroprusside method5.
The blank carried throughout these methods was used to correct
for non-algal nitrogen.
-------
o
o
CO
IV. CBOD and NOD Kinetics in the Potomac Estuary
Biochemical oxygen demand (BOD) is a bioassay in which the
oxygen utilization of a complex and changing population of micro-
organisms is measured as they respire in a changing mixture of
nutrients. That portion of the BOD due to the respiration of organic
matter by heterotrophic organisms is termed the carbonaceous oxygen
demand and that portion resulting from autotrophic nitrification
is termed nitrogenous oxygen demand. Nitrification is the conversion
of ammonium to nitrate by biological respiration. These BOD
components were delineated using an inhibitor to nitrification. The
inhibitor, formula 2533 of the Hach Chemical Company, has been shown
2J&.7
to effectively stop the growth of Nitrosomonas . The product consists
of 2-chloro-6 (trichloromethyl) pyridine, known as nitrapyrin, plated
onto an inorganic salt. The salt serves as a carrier because it is
soluble in water. The organic component is not biodegradable, even
after 30 days of BOD incubation, and therefore does not contribute
to the measured carbonaceous oxygen demand2.
The shape of the oxygen depletion curves (Figures 2, 3, and 4)
were such that the slope of the curves decreased with increased time
of incubation.
Figure 2: General BOD Curve
Curve Equation: y = L0(l-10"kt)
t = elapsed time of incubation in the dark at 20°C
y = BOD; mg/1 oxygen consumed after time t
L0 = ultimate BOD; the oxygen used in the total
degradation of the substrate
k = deoxygenation constant; a constant which
reflects the rate at which a substance is
oxidized--a function of temperature, biota
and the nature of the substrate.
Time
-------
The rate of reaction associated with oxidation-respiration (Ay/At)
was initially rapid corresponding to an initial relatively large
substrate concentration. This rate decreased with time as the
oxidizable substrate was depleted. Other nutrients are provided
in excess and do not effect the rate of oxygen consumption in the
standard BOD test. The quantity and nature of the organic material
in the sample will limit oxygen consumption and determine the rate
of depletion. This type of reaction, in which the rate is proportional
to the amount of the reactant remaining at any time is referred to
as a "first order" reaction. In general, the first order reaction
pattern was observed for both the carbonaceous oxygen demand and the
nitrogenous oxygen demand BOD components of Potomac River samples.
Long-term BOD incubation data were used to give the best available
estimate of k-jQ and L0 using the Thomas Graphical Determination8-'9''10 in
1 /^
which a plot of (t/y) ' vs. t yielded a linear relation where
k-jQ = 2.61 x (slope/intercept) and Lo = (2.3 x (intercept)3 x k-|o) •
The correlation coefficient of the linearized data was taken as a
measure of goodness of fit to first order reaction kinetics.
The CBOD results for river samples were compiled in Table 2.
The average (n=23) k-|Q value for river CBOD's was 0.051 day" or
ke = 0.12 day"'' with an average correlation coefficient = 0.98 and
standard deviation = 0.03 (base e). The value of ke obtained in a 1977
Potomac study6 was 0.14 day" , with n = 43 and a standard
deviation of 0.02. The ratio of CBODs to BOD5 was found to be 0.58 in
the 1978 study.
The NOD of the river samples (Table 3) followed first order kinetics
with a correlation coefficient of 0.85 (n=22) and an average ke of 0.10
day""'. The standard deviation of ke was 0.06.
-------
Figure 3: River Samples-Oxygen Depletion Curves
Woodrow Wilson Bridge Station 5
Sept. 11, 1978
= .054
8 10 12
Time (Days)
Ft. Washington Station 7
Sept. 11, 1978
16
18 20
8 10 12 14 16
Time (Days)
IB
Total
BOD
NOD
CBOD
»•*
BOD
CBOD,
NOD.
-------
Figure 4 : River Samples-Oxygen Depletion Curves
en
E
7 -
6
5
£ 4 -
OJ o
c 3
c
0)
X
o
Indian Head Station 10
August 28, 1978
8 10 12
Time (Days)
16 18 20
^ 8
•S
16
4J
O)
c
-------
Table 2; Thomas Graphical Determinations of k10, L0, and r for River CBOD's
Date
Aug.
Aug.
Sept.
Sept.
- Sta
14
5
7
8A
10
n
14
16
28
5
7
8A
10
n
14
16
n
5
7
8A
10
n
14
16
25
5
7
8A
10
n
14
16
r
.931
.951
.966
.958
.991
.984
.985
.993
.996
.992
.994
1.000
.990
.996
.994
.990
.987
.989
.940
.981
.997
.999
.996
(.931)
(.231)
(-.231)
(.126)
(.557)
(day'1 )
.045
.059
.038
.057
.067
.062
.089
.046
.040
.039
.033
.029
.027
.056
.059
.054
.044
.044
.041
.054
.069
.079
.049
(.020)
Lag
r: (correlation coefficient)
n = 23
Average = .98
Std. deviation = .02 (base 10)
4.5
5.7
6.5
5.2
6.7
3.4
5.8
5.0
5.9
7.9
6.7
5.1
3.5
5.5
5.4
7.2
(15.7)
1.8
2.1
2.4
1.7
1.9
0.9
2.8
2.5
2.7
3.1
2.7
1.9
1.6
3.0
3.2
3.1
(3.2)
3.9
4.7
5.4
4.1
5.0
2.4
5.4
4.7
5.4
6.8
5.9
4.3
3.2
5.3
5.3
6.5
(9.5)
43
43
71
51
60
38
93
4.2
4.9
3.4
2.8
3.2
2.4
3.0
.39
.61
.70
.69
.49
.41
6.4
4.4
4.4
3.9
3.6
7.9
calc. = Calculated value based upon
Thomas Graphical determina^io
or ke = .12 day
n = 23
Average = .051 day"1 c
Std. deviation = .015 day"1 (base 10)
CBOD5/POD5:
n = 19
Average = .58
Std. deviation = .15
-1
-------
*"" Table 3: Thomas Graphical Determinations of k
10'
-0'
and r for River NOD's
Date
Aug.
- Sta
14
5
7
8A
10
n
14
16
r
.957
.780
.939
.600
.949
.802
-.441
(da>)
.077
.032
.037
.019
.037
.024
Lag
"-0
(nig/1 )
1.7
4.7
5.5
5.3
3.0
3.6
Calc.*
MOD5
(mg/1 )
1.0
1.4
1.9
1.0
1.0
.8
Calc.
NOP2o
(mg/1 }
1.7
3.6
4.5
3.0
2.4
2.4
Potential**
MOD
(rag/1 )
2.5
2.9
2.8
1.9
2.3
1.3
( .9)
Aug. 28
5
7
8A
10
11
14
16
.600
.99.5
.978
.996
.989
.876
.877
.017
.067
.039
.037
.048
.049
.030
13.8
5.2
2.9
3.1
3.1
1.9
0.8
2.4
2.8
1.0
1.1-
1.3
1.5
0.2
7.4
5.0
2.4
2.5
2.7
1.6
0.6
Sept. 11
Sept. 25
5
7
8A
10
n
14
16
.974
.216
-.276
.658
.727
-.735
.995
.104
Lag
Lag
.022
.023
Lag
.088
r: (correlation coefficient)
n = 22
Average = .86
Std. deviation = .14 (base 10)
6.7
4.0
5.2
1.1
4.7
.9
1.2
0.7
6.7
2.5
3.4
1.1
7.2
5.1
2.5
2.4
2.3
1.5
1.4
5
7
8A
10
11
14
16
.877
.994
.628
.755
.937
-.619
-.381
.049
.098
.028
.023
.039
Lag
Lag
9.1
2.6
4.8
5.0
4.7
3.9
1.7
1.3
1.2
1.7
8.1
2.5
3. A
3.3
3.9
7.0
2.9
2.9
3.1
2.3
(1.4)
(1.4)
8.3
(5.0)
(4.3)
3.4
3.7
(3.5)
3.3
* calc. = calculated
** Potential MOD = 4.57 x TKN
= 22
Average = .045 day""1 or ke = .104 day'1
""* Std. deviation = .026 day'1 (base 10)
-------
The NOD results agreed with previous Potomac demand studies8 in which
the average NOD ke was 0.14 day""1 with a standard deviation of 0.05.
The larger standard deviation observed for the NOD reflects
both the more fragile nature of nitrification11 and the method by
which it was determined—uninhibited depletion minus inhibited depletion.
The NOD20 was found not to be significantly different from the
potential NOD expressed as 4.57 x TKN (Figure 5). The critical value
of the paired t-test at a 95% confidence level was 2.08 and the
calculated value was 0.37. The 4.57 constant is the stoichiometric
conversion factor for the milligrams of oxygen consumed by the oxidation
of ammonia to nitrate.
The CBOD kinetics observed for the sewage treatment plant effluents
were first order with an average ke of 0.16 day"^ (n = 36 and standard
deviation of 0.05). The average correlation coefficient was 0.985
(Table 4, Figure 6).
The NOD kinetics observed for the sewage treatment plants were
characterized by a lag period (Figure 6) which resulted in poor
correlation to first order reaction kinetics (Table 5). This lag
time was probably an artifact of the APHA dilution method, since
nitrification in the receiving waters was immediate. Because the
Potomac waste treatment effluents are characterized by high ammonia
levels6, the initial lack of nitrification is probably the result of
an insignificant number of nitrifying bacteria in the samples and/or
in the seed innoculum. The long term BOD oxygen depletion data is
included in Section VII.
-------
Figure 5: NOD20 (Inhibitor) vs NOD (TKN x 4.57) River Water Samples
n -
10-
9-
8-
P ^
in
*i-
x— 6^
*£ en
5-
4-
3-
2-
1 -
v = 19778
. = 1978
1978
NOD9n vs (TKN) X 4.57
^H = 22
Correlation coefficient = .87
Least Squares: Slope = .886;
y-intercept = .455
Paired t test
Degrees of freedom = 21
t found = .374
t critical (a = .050;
a/2 = .025) = 2.080
234 56789 10 11
NOD20 (Inhibitor)
(mg/1)
-------
Table 4: Thomas Graphical Determinations of k-|0, L0, and r for STP CBOD's
Date - Sta
Aug. 14
S-l
S-2
S-3 E
S-3 W
S-4
S-5
S-6
S-7
S-8
Aug. 28
S-l
S-2
S-3 E
S-3 W
S-4
S-5
S-6
S-7
S-8
Sept. 11
S-l
S-2
S-3 E
S-3 W
S-4
S-5
S-6
S-7
S-8
Sept. 25
S-l
S-2
S-3 E
S-3 W
S-4
S-5
S-6
S-7
S-8
Name
Piscataway
Arlington
Blue Plains
Blue Plains
Alexandria
Westgate
Hunting Creek
Dogue Creek
Pohick Creek
Piscataway
Arlington
Blue Plains
Blue Plains
Alexandria
Westgate
Hunting Creek
Dogue Creek
Pohick Creek
Piscataway
Arlington
Blue Plains East
Blue Plains West
Alexandria
Westgate
Hunting Creek
Dogue Creek
Pohick Creek
Piscataway
Arlington
Blue Plains
Blue Plains
Alexandria
Westgate
Hunting Creek
Dogue Creek
Pohick Creek
East
West
k
r
1.000
.997
.999
.997
.999
.995
1.000
.993
1.000
Mo
(day'l)
.060
.032
.081
.054
.080
.053
.050
.064
.024
Lo
(mg/1)
12.8
17.3
109.4
21.1
45.9
18.3
29.3
24.7
31.4
Calc.*
CBOD5
(mg/1)
6.4
5.3
66.3
9.7
27.7
8.3
12.9
12.9
7.44
Calc.
CBOD20
(mg/1 )
12.0
13.2
106.7
19.3
44.8
16.7
26.4
23.4
20.8
East
West
-------
Figure 5: STP Effluent Samples - Oxygen Depletion Curves
50 -
? 40 -
C
o
>
X
' O
30
20
10
Piscataway STP Station 1
August 14, 1978
r = -.744
-N-
Total
BOD
NOD
r = 1.0 k10 - .060
8 10 12 14
Time (Days)
•CSOD
16 18 20 22
c
o
cu
d)
a
C51
>>
X
o
90
80
70
60
50
40
30
20
10
0
Westgate STP Station 5
September 11, 1978
Tota"
BOD
NOD
CBOD
i
8
10
12 14
i
16
18 20
i
22
-------
Table 5: First Order Correlation Coefficients for STP NOD's
Sta. Name
S-l Piscataway
S-2 Arlington
S-3 Blue Plains East
S-3 Blue Plains West
S-4 Alexandria
S-5 Westgate
S-6 Hunting Creek
S-7 Dogue Creek
S-8 Pohick Creek
r = correlation coefficient
Aug 14
r*
-.744
.060
-.574
-.335
-.597
-.591
-.538
.957
-.722
Aug 28
r
-.863
-.995
-.886
-.892
-.905
-.902
-.582
-.993
-.982
Sept 11
r
-.629
.351
-.642
.972
-.994
-.778
-.594
-.778
-.709
Sept 25
r
-.210
.987
-.816
-.833
-.872
-.619
-.816
-.829
-.619
-------
V. Oxygen Demand of Algal Respiration and Algal Decay
Potomac BODs samples containing algae historically6'12 expressed
significantly high oxygen demand. The oxygen demand of such samples
was the result of: algal respiration; the decay of phytoplankton; and
the carbonaceous and nitrogenous demand of other non-algal sample
constituents. To resolve the BOD fractions of the sample, it was
assumed that algae represented the only significant particulate
contribution to the BOD of the sample. The non-algal BOD of the
sample was assumed to be associated with the soluble organic and
ammonium/nitrite fractions of the sample. The non-algal or background BOD was
measured in the supernatant which had been obtained from the
centrifugation of the algae containing samples. It was further assumed
that the BOD of freeze-dried algae corrected for seed addition and
the BOD of the dilution water (river water supernatant) represented
the biochemical oxygen demand of algal decay. Freeze-drying has been
shown to effectively kill phytoplankton without significantly altering
their physical structure13 thus providing a method of separating algal
respiration and algal decay measurements in a BOD analysis.
The results of these experiments are presented in Figures 7,8,and 9
and Tables 6 and 7. Algal decay was found to be the major contribution
to algal 8005 with an average mg algal BODg per yg chlorophyll a_ of
0.019. Algal respiration represented about 30% of the algal BODc
contribution with an average of £.008 mg algal BOD^ per yg chlorophyll a_.
The predominent species present in the Potomac during this study was the
-------
Figure 7: Oxygen Depletion Curves of Algal Respiration and Decay
September 14, 1978
7 4
6 -
5 -
I 4
OJ
QJ
c
»
X
o
3 -
1 -
River water supernatant used as dilution water
O Algal suspension
Freeze,
Dried
X Algal suspension,
freeze-dried
River water
supernatant
blk
066 day'1 L0 = 2.0
r = .909 kin
11 14
Time of Incubation (days)
25™
7 -
5 -
- 4 -
OJ
3 -
c
O)
en
52
1 -
River water supernatant used as dilution water
1 ml seed/300 ml BOD bottle
Freeze*
Dried
049 day'1 L0 = 2.3
11 14
Time of Incubation (days)
w
2C
'•N»
-------
Figure 8: Oxygen Depletion Curves of Algal Respiration and Decay
September 6, 1978
1 ml Seed/BOD Bottle
20
18
16
14
° 12
10
en
e
-*->
(U
O)
en
X
O
8 -
6
4
O Algal suspension
X Algal suspension, freeze-dried
• River water supernatant blk
! I 1
i
5
I 1 f 1
8
I
12
= .989
Freeze
Dried
Supernatant
Blk
i
19
Time of Incubation (days)
I E 1 I 1 I I I 1 ! I I ! i 1
i
33
i i I I I I
-------
,Ji DlrJt1d. jUrvl- if /i^JI Rl.rlrafc. i an! . ica>l
September 6, 1978
II I i If I i I J f
20
18
16
14
0)
r—
c
(U
10 -
8 -
6
4
2
0
O Algal suspension
X Algal suspension, freeze-dried
• River water supernatant blk
= .987
T
12 19
Time of Incubation (days)
Freeze
Dried
33
-------
Table 6: Phytoplankton Oxygen Depletion
Date/Sample
Days of Incubation
Sept. 6, 1978
Algal Suspension
Algal Suspension
Freeze-Dried
River Water
Supernatant Blk
Seeded Algal
Suspension
Seeded Algal
Suspension
Freeze-Dried
Seeded" River Water
Sept. 14, 1978
Algal Suspension
Algal Suspension
Freeze-Dried
River Water
Supernatant Blk
Seeded Algal
Suspension
Seeded Algal
Suspension
Freeze-Dried
Seeded River Water
5
9.8
6.4
3.0
10.0
9.3
2.8
5
2.4
2.2
1.4
2.6
2.0
1.1
8
12.0
8.5
3.4
12.6
10.8
3.3
11
5.0
3.8
1.2
5.0
3.5
1.4
12
13.8
9.8
3.6
14.4
12.0
3.6
14
5.1
3.6
1.7
5.3
3.2
1.8
19
16.6
11.4
9.3
17.2
14.3
4.4
25
6.7
5.0
1.9
7.0
4.8
2.1
33
19.1
13.1
5.1
19.8
16.1
5.2
-------
Table 7: BODs Requirements for Algal Decay and Respiration
Decay
Date
Sept. 6
Sept. H
Sept. 6
Sept. H
//
I I BOD5 -
1 ufreeze-
\ dried
algal
suspension)
mg/1
6.4
2.2
9.3
2.0
Background^
BOD5 /
mg/1
3.0
1.4
2.8
1.1
\
DilutionU
factor /
/
6.0
15.0
6.0
15.0
chloro a_
yg/l
1386
810
1386
810
average
Respiration
/
\
Date
Sept. 6
Sept. 14
Sept. 6
Sept. 14
/.
f( BOD5 -
1 algal
t, Vsuspension
\
mg/1
9.8
2.4
10.0
2.6
BODs \X
(freeze-
dried /
algal
suspension)
mg/1
6.4
2.2
9.3
2.0
\
Dilution U
factor /
/
6.0
15.0
6.0
15.0
chloro a_
yg/l
1386
810
1386
810
average
5-Day
Algal Decay
=
mg 62 depletion
yg cm or a_
.0147
.0148
.0281
.0167
.019
5 -Day
Algal Respirati
=
mg 02 depletion
yg cnior a_
.0147
.0037
.0030
.0111
.008
«
•M
""
— '
•w.
K.<
W^
wm
-
fei(
1
W>^
«•
Ml
^.
-
HUH
mg
IBI
-------
filamentous blue-green algae Psuedanabaena. Figures 7,8,and9 also
revealed that seeding of the samples with 1 ml per bottle of stale
settled sewage1 had little effect upon the amount and rate of oxygen
depletion. This suggested that the supernatant contained sufficient
microorganisms for algal decay.
VI. Phytoplankton Elemental Analysis and Methods of TKN Digestion
of Algal Samples
The algae bloom of Psuedanabaena occurred in mid to late September
with a chlorophyll a_ peak of 159 yg/1 on September 27. The elemental
composition of the phytoplankton is compiled in Table 8. The average
elemental ratios to chlorophyll a_were: .021 mg C/yg chlorophyll a_;
.0054 mg N/pg chlorophyll a_; and .0020 mg P04/yg chlorophyll a_. It
should be emphasized that the results are based on the overall
phytoplankton standing corp. The nitrogen values reported for elemental
analysis were obtained by the automated colorimetric phenolate procedure
employing the continuous (helix) digestor with preliminary manual
digestion. Neither the Technicon block digestor nor the Technicon continuous
digestor alone provided satisfactory digestion of algal TKN. The data
from side-by-side algal digestions are compiled in Table 9. The
average recovery relative to preliminary manual digestion for the
Technicon continuous digestor and block digestor were -58% and 83%
respectively. This suggested that 42% of algal nitrogen was refractory
to the Technicon continuous digestor. This agreed with a 50% TKN recovery
estimate suggested in a previous study.lk
-------
i i i i ii t j 11 11 i
Table 8; phytoplankton Elemental Analysis
If II II 1 i II I i I i 11 II li
Date
Sept. 7
Sept. 11
Sept. 26
Sept. 28
Station
5-A
8-A
9
10
10-B
8-A
9 .
10-B
11
8-A
9
10
10-B
11
7
9
10
10-B
11
rage
. deviation
mg TOC
yg chloro a^
.017
.019
.015
.027
.027
.024
.023
.019
.026
.018
.020
.021
.018
.018
.019
.020
.022
.021
.004
mg TOC
mg TSS
.147
.147
.093
.171
.124
.130
.130
.096
.119
.127
.134
.112
.13
.022
mg TKN
yg chloro a^
.0057
.0052
.0052
.0054
.0065
.0054
.0052
.0058
.0086
.0060
.0060
.0060
.0042
.0043
.0035
.0039
.0044
.0054
.0012
mg TKN
mg TSS
.050
.040
.033
.035
.030
.029
.028
.029
.039
.042
.040
.035
.036
.007
mg P04
yg chloro a_
.0021
.0020
.0021
.0020
.0029
.0023
.0024
.0023
.0023
.0021
.0021
.0026
.0028
.0017
.0016
.0018
.0018
.0020
.0022
.0012
.0012
.0010
.0010
.0014
.0020
.0005
mg P04
mg TSS
.018
.015
.013
.013
.013
.012
.013
.012
.012
.011
.010
.012
.013
.012
.012
.012
.012
.011
.012
.013
.002
mg TSS
yg chloro a_
.115
.130
.158
.156
.220
.185
.201
.218
.142
.148
.189
.169
.035
-------
Table 9: Results From Three TKN Digestion Methods
Date
Sept.
Sept.
Sept.
Sept.
Station
7 5-A
8-A
9
10
10-B
11 8-A
9
10-B
n
n s
8-A
9
10
26 8-A
9
10
10-B
n
average
std. deviation
Manual
mg/1
TKN
14.52
15.14
15.14
14.89
15.89
15.89
15.89
14.52
15.14
29.27
28.28
23.32
29.05
21.73
25.17
34.66
31.95
26.74
Block
mg/1
TKN
11.10
14.50
13.03
14.47
14.09
13.63
14.06
13.09
14.36
19.49
20.00
-__
—
16.58
17.74
20.63
19.46
30.88
28.02
24.00
26.30
20.60
20.32
Helix
mg/1
TKN
9.15
9.52
9.27
9.52
9.27
9.21
8.81
8.24
8.06
12.92
-12.61
11.83
11.83
13.65
16.86
22.36
22.84
18.53
Helix
Manual
.63
.63
.61
.64
.58
.58
.55
.57
.53
.44
.45
.51
.41
.63
.67
.65
.71
.69
.58
.09
Block
Manual
.76
.95
.86
.97
.89
.86
.88
.90
.95
.67
.71
_..
—
.76
.82
.82
.77
.89
.81
.75
.82
.77
.76
.83
.08
Helix
Block
.82
.66
.71
.66
.66
.68
.63
.63
.56
.66
.63
_-_
___
.82
.77
.82
.87
.72
.80
.95
.87
.90
.91
-------
VII. Potomac River Long-Terra BOD Survey Data - Summer 1978
Date 8/14/78
Station
5
Days of Incubation
10 15
8-A
10
n
14
16
T*
C*
N*
T
C
N
T
C
N
T
C
N
T
C
N
T
C
T
C
N
2.4
1.3
1.1
2.7
1.3
1.4
4.3
2.3
2.0
3.9
2.9
1.0
4.6
3.5
1.1
3.5
2.6
0.9
1.8
1.6
0.2
3.0
1.4
1.6
4.4
1.3
3.1
6.3
2.8
3.5
5.3
3.1
2.2
5.8
4.0
1.8
4.7
2.9
1.8
2.0
1.6
0.4
3.4
2.1
1.3
4.9
1.7
3.2
8.0
3.9
4.1
6.8
4.0
2.8
7.0
4.7
2.3
5.6
3.7
1.9
2.4
2.0
0.4
21
3.8
2.2
1.6
5.3
1.9
3.4
8.7
4.4
4.3
7.2
4.4
2.8
7.3
5.0
2.3
6.2
3.8
2.4
2.9
1.8
1.1
Date 8/28/78
Station
5
T
C
N
Days of Incubation
7 13 20
4.3 9.3 10.8
2.4 3.2 3.9
1.9 6.1 6.9
8-A
T 6.2
C 2.7
N 3.5
T 4.4
C 3.1
N 1.3
*T-BOD (mg/1)
*C-CBOD (mg/1)
*N-NOD (mg/1)
8.0
3.8
4.2
6.4
4.3
2.1
9.4
4.7
4.7
7.7
5.4
2.3
-------
VII. Potomac Rfver Long-Term BOD Survey Data * Summer 1978 (con't)
Date 8/28/78 (con't)
Days of Incubatfon
7 13
Station
10
11
14
16
Date 9/11/78
Station
5
8-A
10
11
14
16
T
C
N
T
C
N
T
C
N
T
C
N
3.6
2.2
1.4
4.2
2.5
1.7
1.4
1.2
0.2
3.8
3.5
0.3
5.2
3.2
2.0
6.1
3.9
2.2
2.7
1.8
0.9
4.9
4.5
0.4
20
6.6
4.1
2.5
7.6
4.9
2.7
3.9
2.4
1.5
5.8
5.2
0.6
Hays of Incubation
10 14
21
T
C
N
T
C
N
T
c
N
T
C
N
T
C
N
T
C
N
T
C
N
3.7
1.7
2.0
3.3
1.9
1.4
2.1
2.1
—
2.5
1.9
0.6
___
—
1.2
1.2
0
2.2
2.1
0.1
8.9
2.9
6.0
4.9
3.1
1.8
4.8
3.6
1.2
4.4
2.9
1.5
3.9
2.0
1.9
2.0
1.7
0.3
3.5
3.5
0
9,8
3.5
6.3
6.0
3.9
2.1
7.7
4.6
3.1
6.6
4.2
2.4
6.3
3.2
3.1
2.8
2.3
0.5
4.3
4.2
0.1
11.0
4.0
7.0
6.7
4.5
2.2
9.1
6.2
2.9
7.8
5.0
2.8
7.1
4.1
3.0
3.8
2.7
1.1
5.0
4.6
0.4
12.2
4.6
7.6
7.6
5.4
2.2
9.9
6.7
3.2
8.9
5.9
3.0
8.0
4.0
4.0
4.5
3.2
1.3
5.8
5.0
0.8
-------
VII. Potomac River Long-Term BOD Survey Data - Summer 1978 (con't)
Date 9/25/78
Station
5
8-A
10
n
14
16
T
C
N
T
C
N
T
C
N
T
C
T
C
N
T
C
N
T
C
N
Days of Incubation
3 7 14
6.1 8.5 11.0
2.3 3.8 4.8
3.8 4.7 6.2
2.7 6.2 8.4
2.1 3.8 5.7
0.6 2.4 2.7
2.5 7.1 10.5
2.1 4.1 7.6
0.4 3.0 2.9
2.5 7.6 11.0
2.0 6.2 9.1
0.5 1.4 1.9
2.3 5.7 11.2
1.5 3.8 8.6
0.7 1.9 2.6
0.8 2.0 4.5
0.7 1.1 2.9
0.1 0..9 1.6
1.1 1.6 2.7
0.6 0.7 1.7
0.5 0.9 1.0
Date 8/14/78
Station
S-l
T
C
N
20.1
7.2
12.9
Days of Incubation
10 15
38.7
9.6
29.1
41.6
10.8
30.8
21
43.5
11.4
32.1
S-2
S-3 (E)
T
C
N
T
C
N
21.0
6.0
15.0
81.0
75.0
6.0
22.8
9.0
13.8
157
88
.5
.5
41,
11,
29,
69.0
174
96.0
78.0
55.5
13.2
42.3
181,
96,
85.5
-------
VII. Potomac STP Long-Term BOP Survey Data - Summer 1978 (con't)
Date 8/14/78 (con't)
Station
S-3 (W)
S-4
S-5
S-6
S-7
S-8
Date 8/28/78
Station
S-l
S-2
S-3 (E)
S-3 (W)
T
C
N
T
C
N
T
C
N
T
C
N
T
C
N
T
r
N
T
C
N
T
C
N
T
C
N
T
C
N
Days of Incubation
6 10 15 21
21.6 60.0 73.8 77.4
10.8 15.0 18.0 18.3
10.8 45.0 55.8 59.1
36.0 72.0 87.0 92.3
31.5 36.8 40.5 40.3
4.5 35.2 46.5 52.0
14.1 41.7 59.4 72.6
9.6 12.8 14.4 16.5
4.5 28.9 45.0 56.1
18.6 39.9 51.3 55.8
14.7 20.0 23.6 25.8
3.9 19.9 27.7 30.0
30.6 44.4 43.5 46.8
15.2 18.0 20.7 22.5
15.4 26.4 22.8 24.3
10.2 38.7 56.4 75.5
8.7 13.1 17.4 21.2
1.5 25.6 39.0 54.3
Days of Incubation
7 13 20
9.6 43.7 71.7
7.8 9.8 10.5
1.8 33.9 61.2
12.3 22.8 46.8
7.8 8.4 8.6
4.5 14.4 38.2
28.5 79.5 148.5
27.0 36.0 36.8
1.5 43.5 111.7
24.0 67.5 117.8
21.0 27.0 28.5
3.0 40.5 89.3
-------
VII. Potomac STP Long-Term BOD Survey Data - Summer 1978 (con't)
Date 8/28/78 (con't)
Station
S-4
S-5
S-6
S-7
S-8
Date 9/11/78
Station
S-l
S-2
S-3 (E)
S-3
S-4
Days of Incubation
13
20
T
C
N
T
C
N
T
C
N
T
C
N
T
C
N
T
C
N
T
C
N
T
C
N
T
C
N
T
C
N
42.0
33.0
9.0
9.5
8.9
0.6
19,
13,
6,
25,
15,
10,
n,
10,
0.9
11.4
7.8
3.6
28.8
6.0
22.8
13.5
13.5
13.5
12.0
1.5
1.8
15.5
1.5
Days
6
39.0
10.2
28.8
50.4
8.4
42.0
20.3
20.3
0
22.5
18.0
4.5
27.0
24.0
3.0
87.0
39.8
47.2
22.8
10.4
12.4
42.0
17.7
24.3
41.4
20.1
21.3
22.4
16.1
6.3
132.0
42.8
89.2
47.7
11.7
3F.O
47.9
20.1
27.8
53.6
21.6
36.0
52.4
20.4
32.0
of Incubation
10
52.8
11.4
41.4
68.4
8.4
60.0
34.5
22.5
12.0
49.5
21.0
28.5
46.5
27.0
19.5
14
62.4
13.2
49.2
70.8
8.4
62.4
69.0
24.0
45.0
78.0
22.0
56.0
76.5
27.0
49.5
21
63.0
15.0
48.0
87.0
10.4
76.6
79,
28,
51.0
90.0
24.0
66.0
99.0
31.0
68.0
-------
VII. Potomac STP Long-Terra BOD Survey Data - Summer 1978 (con't)
Date 9/11/78
Station
S-5
S-6
S-7
S-8
Date a/25/78
Station
S-l
S-2
S-3 (E)
S-3 (W)
S-4
S-5
Days of Incubation
6 10 14
21
T
C
N
T
C
N
T
C
N
T
C
N
9.0
9.0
0
9.9
9.9
0
9.6
9.0
0.6
7.8
7.8
0
14.4
13.2
1.2
15.0
15.0
0
14.4
13.2
1.2
12.0
10.2
1.8
44.4
16.2
28.2
32.4
17.4
15.0
31.8
16.2
15.6
42.6
14.4
28.2
76.2
16.8
59.4
51.6
18.0
33.6
55.8
18.6
37.2
69.0
16.8
52.2
91.2
18.6
72.6
55.2
21.0
34.2
64.2
22.8
41.4
79.8
21.6
58.2
T
C
N
T
C
N
T
C
N
T
C
N
T
C
N
T
C
N
7.8
5.4
2.4
22.8
5.4
17.4
31,
19,
12.0
63.0
27.0
36.0
30.0
24.0
6.0
9.0
9.0
0
Days of Incubation
7 14
40.2 49
13.8 14
26.4 34.8
60.0 91.8
12.6 13.8
47.4 78.0
69,
31,
37.5
123.0
45.0
78.0
52,
31,
21.0
15.6
11.4
4.2
.2
.4
108
37,
70,
163.
60,
103,
m,
37,
73.5
59.4
13.8
45.6
-------
VII. Potomac STP Long-Term BOD Survey Data - Summer 1978 (con't)
Date 9/25/78 (con't) Days of Incubation
3 7 14
Station
S-7
S-8
T
C
N
T
C
N
11.4
11.4
0
14.4
9.6
4.8
21.0
16.2
4.8
60.0
11.4
48.6
42.0
20.4
21.6
94.8
15.6
79.2
-------
I I
References
1. "Standard Methods for The Examination of Water and Wastewater,"
14th ed.f APHA, 1975.
2. Slayton, J.L. and Trovato, E.R., "Simplified N.O.D. Determination,"
34th Annual Purdue Industrial Waste Conference, Purdue University 1979,
3. Strickland, J.D.H. and Parsons, T.R., "A Manual of Sea Water
Analysis," Bulletin 125, Fisheries Research Board of Canada,
Ottowa, 1960, p. 185.
4. Environmental Protection Agency, Methods for Chemical Analysis
of Water and Wastes. 1974.
5. Gales, M.E., "Evaluation of The Technicon Block Digester System
for Total Kjeldahl Nitrogen and Total Phosphorus," EP4-600/4-78-015,
Feb. 1978, Environmental Monitoring Series. E.P.A. Cincinnati,
Ohio.
6. Young, J.C., "Chemical Methods for Nitrification Control,"
24th Industrial Waste Conference, Part II Purdue University,
pp. 1090-1102, 1967.
7. Young, J.C., "Chemical Methods for Nitrification Control,"
J.W.P.C.F.. 45, 4, pp. 637-646 (April 1973).
8. Slayton, J.L. and Trovato, E.R., "Carbonaceous and Nitrogenous
Demand Studies of The Potomac Estuary, AFO Region III, Environmental
Protection Agency, 1977.
9. Thomas, H.A., "Graphical Determination of B.O.D. Curve Constants,"
Water and Sewage Works, p. 123-124, (March 1950).
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B.O.D. Data," Sewage and Industrial Works. 22, p. 1343-1355, 1950.
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Bacteria in a Polluted Stream," The State Univ., New Brunswick,
N.J., Water Resources Res. Inst. W7406834, Feb. 1974.
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Conditions In The Upper Potomac Estuary, E.P.A. 903/9-78-008,
July 1978.
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14. Slayton, J.L. and Trovato, E.R., "Algal Nutrient Studies of the
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35
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