v>EPA
United States
Environmental Protection
Agency
V
Municipal Environmental Research^'
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-81-095 July 1981
Project Summary
Feasibility Study of Open
Tank Oxygen Activated
Sludge Wastewater Treatment
Kerwm R Rakness
The pilot plant for this study con-
sisted of one oxygenation basin and
two clarif iers capable of treating 151
L/min (40 gpm). The system treated
primary effluent from the Englewood,
Colorado, municipal wastewater treat-
ment facility. The influent flow rate
was adjusted to attain average aera-
tion reactor detention times ranging
from 0.94 to 3.3 hr. The pilot plant
operation was conducted in two
phases. Treatment performance during
both phases was excellent. Final ef-
fluent BOD5 concentrations and sec-
ondary BOD5 removals averaged less
than 20 mg/L and greater than 90
percent, respectively. No degradation
in process removal efficiency occurred,
even at organic loadings as high as
1.23 kg BOD5 applied/day/kg MLVSS
(1.23 Ib BODs applied/day/lb MLVSS)
and volumetric loadings as high as
4.07 kg BOD5 applied/day/m3 (254
Ib BOD5 applied/day/1000 ft3) of
reactor capacity.
Analysis of pilot plant operations
indicated that somewhat less sludge
was produced with the oxygen system
when compared with literature-cited,
typical air sludge production. This
decreased sludge production occurred
and became more pronounced at higher
organic loadings.
Comparisons were made between
literature-cited, typical air-sludge and
oxygen-sludge settling characteristics.
In all cases, the oxygen-sludge initial
settling velocity was greater than
typical air sludge at given TSS con-
centrations.
This Project Summary was devel-
oped by EPA's Municipal Environmen-
tal Research Laboratory, Cincinnati,
OH, to announce key findings of the
research project that is fully docu-
mented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
The investigation of high purity oxygen
for wastewater treatment was originally
conducted by Okun in 1948. No signifi-
cant further development was conducted
until the late 1960's when a "closed
tank" oxygenation process was devel-
oped. The closed tank process demon-
strated that oxygen activated sludge
treatment was feasible and economically
attractive when compared with a parallel
operated air activated sludge system.
Two of the reasons for the attractiveness
of the closed tank process were (1) its
ability to treat wastewater with smaller
aeration reactors than required for air
systems and (2) its ability to achieve
high (90 percent) oxygen utilization
efficiencies.
There are many reasons why an
"open tank" oxygenation system would
be attractive: (1) extensive safety pre-
cautions are required with the closed
tank system, (2) extra expense is involved
in covering and sealing an aeration
reactor as well as a requirement for 0.9
to 1.5 m (3 to 5 ft) of freeboard, (3) other
high purity oxygen activated sludge
treatment systems have been shown to
be feasible and economically attractive
at high oxygen utilization efficiencies,
-------
and (4) existing aeration basins may be
easily converted to oxygen systems in
an open tank concept.
To date, there is one known open tank
high purity oxygen activated sludge
system on the market, MAROX,* mar-
keted by Zimpro Inc. The MAROX system
was originally developed by FMC Corpo-
ration, but Zimpro has subsequently
acquired the rights to the technology.
The basis for performance of the MAROX
system is an ultra fine bubble diffuser
that achieves oxygen utilization effi-
ciencies comparable with those obtained
with closed tank reactor systems.
The MAROX system uses a unique
bubble shear method for dissolution of
pure oxygen to the mixed liquor. The
fixed active diffuser hardware used in
this project has two gas bars adjacent to
each slot that emitted oxygen through
very small capillaries where a high
velocity mixed liquor stream sheared
the bubbles on formation into 50/u- to
100/u-diameter gas bubbles.
Testing was completed using a pilot
plant facility capable of treating sec-
ondary influent (primary effluent) flow-
rates up to 151 L/min (40 gpm). Sec-
onday influent (SI) to the pilot plant was
obtained from the primary treatment
process of the Englew^ood facility. During
the testing period, "one oxygenation
basin and either one or two clanfiers
were in service. The program plan with
both constant flow and the maximum-
minimum diurnal flow conditions are
shown in Table 1. Diurnalflow variations
were selected based on the historical
raw wastewater flow at the Englewood
facility. The program was divided into
two phases with the latter phase using a
broader range of operational controls
and monitoring.
Further information concerning open
tank oxygen activated systems can be
found in the EPA project report "Full-
Scale Demonstration of Open Tank
Oxygen Activated Sludge Treatment"
(EPA-600/2-79-012). The follow-on,
full-scale demonstration project used a
rotating active diffuser, which in general
required less power than the fixed
active diffuser used in this project. The
rotating active diffuser has supplanted
the fixed active diffuser as the standard
oxygen transfer device in the MAROX
open tank oxygen system.
•Mention of trade names or commercial products
does not constitute endorsement or recommenda-
tion for use.
Results and Conclusions
The MAROX oxygen pilot plant pro-
vided data that led to the following
conclusions:
1. Final effluent (FE) BOD5 concen-
trations averaged less than 20
mg/L, even at average volumetric
loadings as high as 4.07 kg BOD5
apphed/day/m3 (254 Ib BOD5
applied/day/1000 ft3) of oxygen-
ation basin capacity and maximum
organic loadings of 1.23 mass
BOD5 applied/day/mass mixed
liquor volatile suspended solids
(MLVSS).
2. Better effluent quality was attained
by operating at return flow/influent
flow (R/Q) ratios between 50 and
60 percent as opposed to R/Q
between 30 and 40 percent.
3. No significant nitrification occurred
during the test program; oxygen-
ation basin detention times ranged
from 0.94 to 3.3 hr.
4. Excellent oxygen feed control re-
sponse was achieved using a dis-
solved oxygen (D.O.) monitoring
and control system to vary oxygen
supply rate.
5. Oxygen utilization efficiencies
averaged 91.5 and 92.5 percent
during two separate oxygenation
basin "off-gas" tests.
6. Oxygen-sludge mixed liquor sus-
pended solids (MLSS) initial settling
velocities were greater than liter-
ature-cited, air-sludge settling
velocities at specific total sus-
pended solids (TSS) concentrations.
7. Oxygen-sludge production values
were somewhat lower than most
literature-cited, air-sludge produc-
tion values.
Recommendations
The following recommendations are
made from the results of the MAROX
pilot plant operation. For oxygen utiliza-
tion efficiency verification in an "open"
oxygenation basin, the following ap-
proach is recommended for activated
sludge systems. (1) Compare the ratio of
mass of oxygen supplied per mass of
BOD5 removed with expected ratios. If
the calculated ratio is equal to or less
than the expected ratio, then the oxygen
utilization efficiency is acceptable. If the
calculated ratio is greater than the
expected ratio, then the oxygen utiliza-
tion efficiency may not be acceptable
and further verification testing is re-
quired. (2) An accurate oxygen utiliza-
tion efficiency can be determined by
using a cap or cover on all or a portion of
the surface area of the oxygenation
basin and conducting an off-gas analysis.
Other indirect methods for obtaining
mass of oxygen used are not acceptable
alternatives
Discussion of Results
Phase I
The Phase I experimental program
consisted of the first three test condi-
tions identified in Table 1. Monitoring
and operating results obtained during
Phase I are shown in Tables 2 and 3,
respectively. Most data listed in Table 2
are self-explanatory. Raw wastewater
BOD5 and TSS concentration values are
Englewood laboratory results for the
raw wastewater entering the treatment
facility.
Phase I process removal efficiencies
were satisfactory despite limited opera-
tional controls and low primary clanfier
TSS removal efficiencies. MAROX sec-
ondary BOD5 removal efficiencies
ranged from 89.8 to 94.3 percent with
TSS removal efficiencies from 78 8 to
87.7 percent. Primary treatment BOD5
removal efficiencies were in an expected {
range of 21.8 to 40 percent. Primary
treatment TSS removal efficiencies
were much lower than expected, ranging
from a negative 17 percent to a positive
21 percent. The low primary TSS re-
moval efficiencies may be attributed to
higher than desired TSS concentrations
of various Englewood inplant recycle
flows, namely anaerobic digester super-
natant, and may have adversely affected
the final effluent quality.
Final effluent during Phase I had
BOD5 concentrations less than 17 mg/L
and TSS concentrations less than 27
mg/L. The slightly higher TSS values
apparently were composed of inert
suspended solids not captured in the
final clarifier. The final effluent probably
contained more inert suspended solids
than normal because of (1)a long sludge
detention time in the clarifier (2.0to 3.9
hr), which contributed to degradation of
mixed liquor quality and (2) a high con-
centration of anaerobic digester super-
natant solids in the SI flow Degradation
of mixed liquor quality was demon-
strated by its poorer ability to capture
solids in the clarifier. The long sludge
detention time in the clarifier was
caused by a lower return sludge flow
rate than was established in Phase II.
The excellent settling characteristics of |
the mixed liquor (SVI ranged from 65.9
to 81.5 ml/g) did not result in a clean-
-------
Table 1.
Program Plan Operating Conditions
Test
No.
1
2
3
4
5
6
7
A verage
Daily Flow
(L/minf
37.8
378
56.7
75.8
94.5
113.5
132.5
Flow
Condition
Constant
Diurnal
Constant
Diurnal
Constant
Dirunal
Constant
Maximum
Daily Flow
(L/min)
47.3
102.0
133.5
Minimum
Daily Flow
(L/min)
22.7
45.5
75.8
Reactor*
Detention
(hr)
3.30
330
2.20
1.65
1.32
1.10
094
Clar.
No.
1
1
1
1
2
2
2
Clarified
Overflow Rate
(m3/day/m2)e
15.2
15.2
22.9
30.5
19.1
22.9
26.7
Clarified
Overflow Rate
(m3/day/m2)
16.7
16.7
25.1
33.5
21.0
25.1
293
8'Based on average daily SI flow.
^Includes clanfier centerwell.
^Excludes clarifier centerwell.
*L/min x 0.264 - gpm
em3/day/mz * 24.5 = gpd/ft2
Table 2. Monitoring Results - Phase I
Parameters Run 1
Run 2
Run 3
Operating conditions
A verage SI flo w, L /min 37.8 37.8 56.7
(gpm) (W) (10) (15)
Flow pattern Constant Diurnal Constant
Run length, days 47 25 54
Wastewater temperature, °C 22 20 13
BODs data
Raw wastewater, mg/L 183 179 245
SI, mg/L 131 140 147
Primary removal. % 18.4 21.8 40.0
FE, mg/L 10 8 16
Secondary removal, % 92.4 94.3 89.8
Primary plus secondary removal, % 94.5 95.5 93.5
Oxygen supplied, mass 02/mass BOD* 2.30 2.60 1.17
TSS data
Raw wastewater, mg/L
SI, mg/L
Primary removal, %
FE. mg/L
Secondary removal, %
Primary plus secondary removal, %
197
187
5.1
19
84.4
90.4
153
179
17*
21
87.7
86.3
157
124
21
26
78.8
83.4
T/7/s indicates an increase of 17%.
sweeping sludge. If the R/Q ratio had
been increased, the lower sludge deten-
tion time in the clarifier might have
improved the mixed liquor quality.
During all periods of Phase I operation,
manual D.O control was provided. The
average D.O. concentration of the mixed
liquor in each pass of the oxygenation
basin was higher than desired during
the first two Phase I tests During the
last part of Phase I, the average D.O.
concentration of the mixed liquor was in
the desired range. In parts of Phase I
operation, the mass of oxygen supplied
per mass of BOD5 removed was larger
than expected because of higher than
desired mixed liquor D.O. concentra-
tions.
Phase I pilot plant operation demon-
strated that the MAROX system can be
satisfactorily operated at high MLVSS
concentrations, high return sludge TSS
concentrations, and long mean cell
residence times (Table 3).
Phase II
The experimental program for Phase
II included the last four test conditions
cited in Table 1 plus reruns of test
conditions Nos. 1 and 3. Monitoring and
operating results obtained during Phase
II are presented in Tables 4 and 5,
respectively. All six periods of operation
during Phase II demonstrated excellent
BOD5 and TSS removals. Final effluent
BODs and TSS concentrations ranged
from 14 to 18 mg/L and from 11 to 15
mg/L, respectively.
Primary treatment BOD5 and TSS
removal efficiencies were acceptable,
ranging from 13.1 to 39.7 percent and
from 16 to 63.5 percent, respectively.
The low primary TSS removal efficiency
of 16 percent is attributed to anaerobic
digester supernatant recycle flow The
final effluent TSS concentration, how-
ever, was much improved over the
Phase I overall final effluent TSS con-
centration Two reasons contributed to
the better effluent quality during this
period (1) operation at higher R/Q
ratios and (2) lower sludge detention
time in the clarifter. The R/Q ratio and
clarifier sludge detention time were 50
percent and 1 hr, respectively During
Phase I, these same parameters were
approximately 40 percent and 3 hr.
During the 95-L/min (25-gpm) flow
condition, the secondary influent TSS
concentration was lower than the over-
all values for Phase I. The lower second-
ary influent TSS concentration may
have contributed to the final effluent
TSS concentration of 13 mg/L. In all but
two periods of Phase II (37.8 L/min (10
gpm) and 56 7 L/mm (15 gpm)), the
sludge detention time in the clanfier
was less than 1.4 hr. In these two
periods, however, the sludge detention
time in the clarifier was 3.3 and 2.5 hr,
with SVI values of 204 ml/g and 184 ml,
respectively Although the settling
characteristics were poorer than de-
sired, the final effluent quality did not
deteriorate (12 and 14 mg/L TSS,
respectively). Sludge in these two peri-
ods was clean-sweeping, even though
-------
Table 3. Operating Results - Phase I
Parameters
Run 1
Run 2
Run 3
Operating conditions
Average SI flow, L/min
Igpm)
Flow pattern
Run length, days
Volumetric loading, kg BOD$/m3/day
(Ib BODS/ 1000 ft3 /day)
Aerator detention time (0.1 hr
Sludge detention time-aerator (Q+R), hr
RAS* flow, L/min
Igprn)
R/Q ratio, %
Sludge detention time-clarifier (Q+R), hr
Clarifier mass loading, kg TSS/day/m3
(Ib TSS/day/ft3)
Overflow rate0, m3/day/m2
(gpd/ff)
Overflow ratec, m3/day/m2
(gpd/ft2)
Sludge aged, days
Mean cell residence time, days
Sludge synthesis, mass excess VSS/
mass BODs removed
F/M ratio, mass BOD5/mass MLSS/day
Oxygen data
Pass A mixed liquor DO, mg/L
Pass B mixed liquor DO, mg/L
Pass C mixed liquor DO, mg/L
Final effluent DO, mg/L
So/ids data
MLSS, mg/L
MLVSS, mg/L
MLVSS/ MLSS ratio, %
RAS TSS. mg/L
RAS VSS. mg/L
RASVSS/RASTSS ratio, %
SVI. ml/gm
aRAS = return activated sludge
^Includes clarifier centerwell.
cExcludes clarifier centerwell.
dBased on TSS in secondary influent.
37.8
110)
Constant
47
0.96
160)
3.3
2.4
14.8
(3.9)
39.4
2.0
161
(33.0)
15.2
(374)
16.7
(411)
13.9
25.6
0.44
0.18
9.3
9.5
8.0
4.1
7,488
5,390
72.0
26,755
19,325
72.2
65.9
37.8
(10)
Diurnal
25
1.03
(64)
3.3
2.3
16.7
(4.4)
43.6
3.9
220
(45.0)
15.2
(374)
16.7
(411)
13.0
27.8
0.57
0.15
9.1
10.1
10.5
5.7
10.206
7,111
69.7
24,448
17,234
70.5
67.7
56.7
(15)
Constant
54
1.71
(107)
2.2
1.6
20.8
(5.5)
36.4
2.8
152
(31.2)
22.7
(561)
25.1
(617)
3.3
7.1
0.77
0.46
3.7
3.6
4.3
1.8
4,877
3,870
79.4
14,139
10,951
77.5
81.5
its settling rate was not as good. The
sludge settling characteristics of the
other four periods were excellent with
SVI's ranging from 67.8 to 74.5 ml/g.
During Phase II, the automatic oxygen
controller was in operation and per-
formed very effectively. The D.O. con-
centration of the mixed liquor in each
pass was within the satisfactory range
of 1 to 4 mg/L. The mass of oxygen
supplied per mass of BODs removed
varied from 0.92 to 1.49.
Results of the total nitrogen series
analyses indicate that no significant
nitrification occurred during Phase II.
Limited TKN and NH3-N removals were
observed. Results of organic analyses
indicated that the relationship of final
effluent COD to final effluent BOD5 was
very erratic. The final effluent COD
concentration ranged from 48 to 94
mg/L, whereas the final effluent BOD5
concentration ranged from 14 to 18
mg/L. The final effluent turbidity test
results were low and consistently ranged
from 4.4 to 6.3 JTU.
No significant decrease in pH occurred
between the SI and FE during Phase II. It
is apparent that most of the C02 pro-
duced during the biological reaction
was removed from the system in a
manner that did not significantly de-
crease the pH of the final effluent.
System Evaluation
The average final effluent BOD5 con-
centration for each test condition never
exceeded 20 mg/L. Primary treatment
removals showed wide variations; how-
ever, primary plus secondary BODs
removals always exceeded 90 percent.
The TSS concentration of the FE never
exceeded 30 mg/L during Phase I, nor
20 mg/L during Phase II. Primary re-
moval efficiencies exhibited wide varia-
-------
Table 4. Monitoring Results - Phase II
Parameters Run 1
Run 2
Run 3
Run 4
Run 5
Run 6
Operating conditions
Average SI flow, L/min
(gpm)
Flow pattern
Run length, days
Wastewater temperature, °C
SI pH
FE pH
FE turbidity, JTU
BOD5 and COD data
Raw wastewater BOD5, mg/L
Sl BOD5, mg/L
Primary BODs removal, %
FE BOD*, mg/L
Secondary BODS removal, %
Primary plus secondary
BOD5 removal, %
Oxygen supplied, mass Oz/mass BODn
SI COD, mg/L
FE COD, mg/L
COD removal, %
TSS data
Raw wastewater, mg/L
SI, mg/L
Primary removal, %
FE. mg/L
Secondary removal, %
Primary plus secondary removal, %
Nitrogen data
SI TKN. mg/L
FE TKN, mg/L
TKN removal, %
SI NHyN, mg/L
FE NHyN. mg/L
NH3-N removal, %
SI NOZ-N + NO3-N, mg/L
FE NOz-N + N03-N, mg/L
37.8
(10)
Constant
30
18.1
6.8
6.7
4.7
282
212
24. 8
15
92.9
9.47
1.49
396
48
87.9
205
134
34.6
12
91.4
94.1
31
20
34.2
18
16
10.6
0.25
0.25
56.7
(15)
Constant
31
19.5
6.9
6.9
4.6
292
210
28.1
16
92.4
94.5
1.32
345
48
85.5
202
119
41.1
14
86.7
93. J
27
13
51.9
19
16
15.8
0.1
0.15
75.8
(20)
Diurnal
31
21.5
6.9
6.9
5.1
289
208
17.6
16
92.3
94.5
1.08
321
61
80.1
175
115
34.3
15
85.6
91.4
27
12
55.6
18
15
16.7
0.1
0.15
94.5
(25)
Constant
23
14.6
7.0
6.9
5.6
191
166
13. 1
14
91.6
92.7
1.17
332
95
70.9
131
110
16.0
13
87.7
90.1
36
28
27.8
29
22
24.1
0.1
0.15
113.5
(30)
Diurnal
30
19.0
6.9
6.9
4.4
297
179
39.7
16
91.1
94.6
0.92
259
57
77.6
233
85
63.5
11
85.8
95.3
29
23
20.7
21
19
9.5
0.5
1.3
132.5
(35)
Constant
31
16.8
7.0
6.9
6.3
262
159
39.3
18
88.7
93.1
1.08
305
74
75.7
200
85
57.5
15
81.4
92.5
26
21
19.2
18
15
16.7
0.1
0.16
tions, even including a negative TSS re-
moval. Primary plus secondary TSS
removal efficiencies were greater than
80 percent during Phase I and greater
than 90 percent during Phase II.
During the study, the pilot facility was
operated under a wide range of loading
conditions. The BOD5substrate removal
rate related to the F/M ratio for both
phases is depicted in Figure 1. The
graph was developed using weekly
average test results for all test condi-
tions. The straight-line relationship of
the graph illustrates that no degradation
in process BOD5 removal efficiency
existed even at the higher F/M ratios.
The slope of the line indicated that on
he average for all tests, 90.2 percent of
the BOD5 applied to the system was
removed.
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Table 5. Operating Results - Phase II
Parameters
Run 1
Run 2
Run 3
Run 4
Run 5
aRAS = return activated sludge
^Includes clarifier centerwell.
^Excludes clarifier centerwell.
"Based on TSS in secondary influent.
Run 6
Operating conditions
Average SI flow, L/min
(gpm)
Flow pattern
Run length, days
Volumetric loading, kg BODs/m3/day
(Ib BODs/1000 ft3 /day)
Aerator detention time (Q), hr
Sludge detention time-aerator (Q+R), hr
RASB flow, L/min
(gpm)
R/Q ratio, %
Sludge detention time-clarifier (Q+R), hr
Clarifier mass loading, kg TSS/day/m3
(Ib TSS/day/ft3)
Overflow rate", m3/day/m2
(gpd/ft2)
Overflow rate0, m /day/m2
(gpd/ft2)
Sludge aged, days
Mean cell residence time, days
Sludge synthesis, mass excess VSS/
mass BODs removed
F/M ratio, mass BODs/mass MLSS/day
Oxygen data
Pass A mixed liquor DO, mg/L
Pass B mixed liquor DO, mg/L
Pass C mixed liquor DO, mg/L
Final effluent DO, mg/L
Solids data
MLSS, mg/L
MLVSS, mg/L
MLVSS/MLSS ratio, %
RAS TSS, mg/L
RAS VSS, mg/L
RASVSS/RASTSS ratio, %
SVI, ml/gm
37.8
(W)
Constant
30
1.54
(96)
3.3
2.12
20.6
(5.45)
54.5
3.3
112
(23)
15.2
(374)
16.7
(411)
4.5
11.2
0.61
0.39
3.0
2.7
3.1
1.2
4.750
3,952
83.2
13,103
10,842
82.7
204
56.7
(15)
Constant
31
2.31
(144)
2.2
1.40
30.2
(8.0)
53.3
2.5
181
(37)
22.9
(56 1)
25.1
(617)
3.2
8.3
0.60
0.57
3.5
4.2
4.5
1.2
5,089
4.044
79.5
13,131
10,390
79.1
184
75.8
(20)
Diurnal
31
3.04
(190)
1.6
1.10
37.8
(10.0)
50.1
1.4
181
(37)
30.5
(748)
33.5
(822)
2.6
5.8
0.46
0.95
1.7
2.3
3.9
1.0
3,962
3,361
84.8
10.850
9,080
83.7
74.5
94.5
(25)
Constant
23
3.03
(189)
1.3
0.83
56.7
(15.0)
60.0
1.0
156
(32)
19.1
(468)
20.9
(514)
2.0
4.1
0.74
0.77
3.8
4.0
4.8
0.6
5.122
4,008
78.4
1 1,583
9,078
78.4
71.5
113.5
(30)
Diurnal
30
3.91
(244)
1.1
0.70
64.6
(17.1)
57.0
1.4
171
(35)
15.2
(561)
25.1
(617)
2.2
6.2
0.50
1.02
3.7
5.2
4.4
1.3
4.743
3.886
81.9
12,221
9.820
80.4
67.8
132.5
(35)
Constant
31
4.07
(254)
0.94
0.62
69.2
(18.3)
52.3
1.5
161
(33)
26.7
(655)
29.3
(720)
1.5
4.9
0.61
1.23
4.4
4.5
6.1
1.3
4.028
3.436
85.3
10,487
8,695
82.9
72.4
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•
CO
CQ •»
I
1.4
1 3
1 2
1 1
1.0
0 9
0.8
07
0.6
0.5
04
0 3
02
0 1
0
Equation of Line
Y = 0.902X + 0.006
0 0.1 0.2 0.3 0.4 05 0.6 0.7 08 0.9 1.0 1 1 12 1.3 14
F/M Ralio, mass BOD5 applied'/day/mass MLVSS
Figure 1. BOD substrate removal rate versus F/M ratio.
Kerwin R Rakness, at the time of this project, was with FMC Corporation, Engle-
wood, CO 8O1 W; he is now with M&l Consulting Engineers, Fort Collins, CO
80525
Richard C. Brenner is the EPA Project Officer (see below)
The complete report, entitled "Feasibility Study of Open Tank Oxygen-Activated
Sludge Wastewater Treatment," (Order No. PB 81-213 274; Cost: $8.00,
subject to change) will be available only from.
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Municipal Environmental Research Laboratory
U.S Environmental Protection Agency
Cincinnati, OH 45268
J US GOVERNMENT PRINTING OFFICE
757-01Z/7249
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Agency Cincinnati OH 45268 Protection
Agency
EPA 335
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