EPA-670/2-73-024
July 1973
INSTREAM AERATION TO CONTROL
DISSOLVED SULFIDES IN SANITARY SEWERS
OFFICE OF RESEARCH AND MONITORING
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
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EPA-670/2-73-024
July 1973
f ' /
'' -
INSTREAM AERATION TO CONTROL
DISSOLVED SULFIDES IN SANITARY SEWERS
by
R. L. Condon, Jr.
R. A. Cooper, Jr.
A. J. Englande, Jr.
Grant No. WPRD 121-01-68
Project 11010 ELP
Program Element 1-B2033
Project Officer
John N. English
U.S. Environmental Protection Agency
National Environmental Research Center
Cincinnati, Ohio 45268
Prepared for
OFFICE OF RESEARCH AND MONITORING
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
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ABSTRACT
Field studies were conducted employing full scale proto-
types of four aeration devices installed in a sanitary
sewage col lection system. The devices used included an
in-I ine Venturi aspirator, an i n-I i nc Vortex-Shear aspira-
tor, an air-I ift pump, and Venturi aspirated U-tubes. Only
the Venturi aspirated U-tubes proved to be; satisfactory
under the conditions of this study. The U-tube installed
on the end of a sewage force main reduced dissolved su I -
fides, at a samp I ing station 1500 ft downstream, from
.30 mg/l to . 02 m9/l (equivalent to a 12 min detention)'
Additionally, the U-tube v i rt ua I I y e I i m i nated the st.r i pp -
ing of HnS in the discharge manhole where a severe odor
problem and corrosive attack had existed. Oxygen demand
in the force main immediately upstream of the U-tube aver-
aged 2.5 mg/l . Oxygen transfer in the U-tube averaged
5.1 mg/l with residual dissolved oxygen in the efHuent
averaging 2.6 mg/l.
As instal led, and with oxygen transfer averaging 5.1 nig/ I,
no modification of existing pumps was required. Higher
transfer concentrations approaching 7 mg/l were obtained
with Venturi aspiration, but resulted in increased pump
head requirements. Transfer concentrations up to 8 my/'!
were obtained with forced air injection, but did not
appear to justify the added cost of blowers and greatly
increased pump head requirements.
No maintenance was required on either of the two Venturi
aspirated U-tubes during two years of continuous operation
in this d em on s t r at ion.
This report was submitted in fuIfiIIment of Project Number
I 1010 ELP, Grant Number WPRD 121-01-68, under the sponsor-
ship of the Environmental Protection Agency by the Depart-
ment of Sanitation, Jefferson Parish, Louisiana, 600 He Iois
Street, Metairie, Louisiana 70005. The Project Director
was Ray L. Condon, Jr.
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CONTENTS
Sect i on Page
I Cone I us i ons I
II Recommendations 3
III Introduction 5
IV Description of the Project 9
Selection of Test Stations 9
Initial Background Data 14
Aerator Design and Installation 15
Test Procedures 30
V Results 35
Test Stations 35
Rainfall and Temperature Background 35
Analytical Testing 37
Airl ift Aerator 39
U-tube Evaluation 44
Venturi and Ashbrook Aerators 66
VI Summary of Results 72
VII References 79
VIII Appendices 80
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FIGURES
F i gure No. Page
I Plan of Demonstration System 10
2 Demonstration System Schematic II
3 Details of Venturi Aspirators 17
4 Plan of ll-tube at Station 5 18
5 Elevation of U-tube at Station 5 19
6 Plan of U-Tube at Station 7 20
7 Elevation of ll-tube at Station 7 2!
8 Original U-tube Entrance Elbow and
Interim Modification 23
9 Final Modification to U-tube
Entrance Elbow 24
10 Plan of Station 31 26
I I Deta i Is of A i rI i ft Aerator 27
12 Log Fractions of Dissolved Sulfides 32
13 I nstream and Air Temperatures 3*:
14 Rainfall and Resulting Flows 35
15 Dissolved Oxygen at Station I 40
16 Dissolved Sulfides at Station I A |
17 Dissolved Sulfides at Station I 42
18 BOD5 and COD at Station I 43
19 Dissolved Oxygen at Station 13 45
20 Dissolved Sulfides at Station 13 45
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F i gure No. Page
2l Dissolved Sulfides at Station 13 47
22 BOD5 and COD at Station 13 48
23 Dissolved Oxygen at Station 6 50
24 Dissolved Sulfides at Station 6 51
25 Dissolved Sulfides at Station 6 52
26 BOD5 and COD at Station 6 53
27 Dissolved Oxygen at Station 40 60
28 Dissolved Sulfides at Station 40 51
29 Dissolved Sulfides at Station 40 62
30 BOD5 and COD at Station 40 63
31 Dissolved Oxygen at Station 7A 55
32 Dissolved Sulfides at Station 7A 67
33 Dissolved Sulfides at Station 7A 68
34 BOD5 and COD at Station 7A 69
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TABLES
Table No. Page
I D.O. and I.O.D. at Stations 5A and 5B 55
2 Aspiration 02 Transfer and Headless
at Stat ion 5 5^
3 D.O. and Dissolved Sulfides at
Stations 5A and 5B 5g
4 D.O. and I.O.D. at Stations 7A and 7B 70
5 Average D.O. and Sulfides before and
after Aeration for a I I Stations 73
6 Average BODr and COD before and after
Aeration for al I Stations 7A
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ACKNOWLEDGEMENTS
The invaluable contributions of Mr. C. L, Swanson, E.P.A.,
Project Officer, over the period when this project was
initiated and through the major portion of the field work
is grateful ly acknowledged. The continuing excel lent co-
operation and assistance rendered by succeeding Project
Officers, Mr. Gerald Stern and Mr. John N. Engl ish, is
also sincerely appreciated.
de Laureal Engineers, Inc. supervisory personnel involved
in this demonstration were:
Mr. R. A. Cooper, Jr., Project Director
Mr. A. J. Englande, Test Supervisor
Mr. D. P. Boudreaux, Computer Programmer
Mr. H. A. Schomaker, Construction Supervisor
Mr. J. Gordon Hebert, Mechanical Engineer
The fuI I cooperation of al I personnel of the Jefferson
Parish Department of Sanitation is gratefully acknowledged
with special thanks to:
Mr. Ray L. Condon, Jr., Director
Mr. Walter Frey
Mr. Rene Schexnayder
Mrs. Mazetta Diedrich
Mr . Rene Chop i n
Finally, the cooperation of Dr. Rex C. Mitchell and Mr.
Joe Quag I ino of Rocketdyne, who worked concurrently in
the initial design characterization and subsequent re-
evaluation of the U-tubes after modification under a
separate contract with the Environmental Protection Agency
is most sincerely appreciated.
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SECTION I
CONCLUSIONS
Dissolved suI fides above O.I PPM caused serious odor prob-
lems and costly corrosive attack to sewers and manhole
structures. Turbulence from force main discharges and
high gravity drops of sewage containing dissolved su I fides
in concentrations of a few hundredths of a milligram per
I iter resulted in totally unacceptable levels of H^S in the
sewer atmosphere.
The Venturi aspirated U-tube, as designed and installed on
the discharge end of two force mains, has demonstrated the
ability to eliminate the turbulence characteristic of con-
ventional force main discharges and to transfer sufficient
oxygen to effectively oxidize the dissolved sulfides in the
sewage stream. For dissolved sulfide concentrations up to
2 PPM the U-tube was effective without modification of pumps
in existing I ift stations. Experience indicated that if dis-
solved sulfides significantly above 2 PPM are encountered
or if physical constraints are imposed on the U-tube design
which I imit the depth of the U-tube to less than 40 ft or
the dimension from the center! ine of the Venturi to the U-
tube discharge to less than 6 ft, an increase in pumping
head of IQ% to 5®% would be necessary. Of extreme signifi-
cance to municipal ities is the fact that the U-tubes in
this demonstration required no maintenance in two years and
did not burden the sewer system with additional mechanical
or electrical devices that usually require considerable
ma i ntenance.
The air-lift aerator in this demonstration, while quite
efficient in transferring oxygen to effect the oxidation, of
sulfides downstream, proved unacceptable because of excess-
ive turbulence and consequent stripping of h^S at the in-
stallation. The in-line Venturi aspirator and Vortex-Shear
aerator installed in a force main did not achieve the same
amount of oxygen transfer as obtained with the U-tube, and
did not el iminate the turbulence at the force main dis-
charge. The stripping of HoS at the force main discharge
makes the in-I ine configurations unacceptable.
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In summary, the Venturi aspirated ll-tubes in this demon-
stration proved highly effective and extremely economical
in the control of dissolved sulfides at and downstream of
force main discharges and merits serious consideration
whenever odor and corrosive attack constitute a problem in
sanitary sewage systems.
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SECTION II
RECOMMENDATIONS
It is recommended that, in existing systems, the app I ica-
tion of a Venturi aspirated ll-tube be considered at the
discharge of any force main that has a flow of 300 GPM or
more and which causes or contributes to odor and corrosion
problems. It is further recommended that, in the cases of
new systems, the application of Venturi aspirated U-tubes
to force main discharges be evaluated against the injec-
tion of air into force mains that have to be specifically
designed for this appI i cat ion.
If a fairly constant flow, upwards of 500 GPM, and a dif-
ferential head in the range of 6 to 8 ft are available the
Venturi aspirated ll-tube can be app I i ed in gravity sewers,
at points other than at force main discharges. However,
variable flow and head requirements impose serious design
constra i nts.
From observations in this demonstration involving U-tubes
designed by Rocketdyne on the basis of techniques deve-
loped and reported under the title "U-tube Aeration" (3)
it is recommended that actual system losses and flows be
accurately determined in all existing systems and that the
substitution of larger diameter pump impel!ers and in-
creased motor HP be weighed against design constraints that
might otherwise be imposed. Consideration should be given
to increasing wet well volume to extend actual pumping time
In ex i st i ng systems this shouId i ncIude the poss i b i I i ty of
installing dual wet wells. The pumping time should be of
maximum duration (at least ten minutes) consistant with an
acceptable detention time of one or two hours in the wet
we I I at minimum flow.
Finally, since the Venturi aspirated U-tube may not adapt
to installation in gravity sewers other' than at force main
discharges, particularly in the case of existing systems,
because of variation in flow and/or the differential head
required, it is recommended that further study be conducted
on the air I ift aerator. This device accommodated a wide
variation in flow and proved highly efficient. As
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configured in this demonstration there was excessive tur-
bulence and stripping of hydrogen sulfide, which despite
the 20 ft high vent provided resulted in a discernible
odor within a radius of several hundred feet during per-
iods of high humidity and still air. It should be possible
to reconfigure this device, minimize I i f t air, and pro-
vide a smooth discharge into the receiving stream similar
to that achieved by the U-tubes. If this can be accompI ish-
ed the air I ift aerator would constitute a highly practical
and efficient aerator readily adaptable to any new or ex-
isting gravity sewer and to any required spacing of aera-
tion dev i ces,
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SECTION III
INTRODUCTION
In August of 1961 de Laureal Engineers, Inc., completed a
master sewerage plan for the East Bank of Jefferson Parish,
an area of 32,000 acres abutting and contiguous with the
City of New Orleans, This plan embodied both future sew-
erage and immediate rehabilitation of exist ing facilities.
In the investigation incidental to the development of this
plan the sewage col lection system and He! ios Treatment
Plant serving the section known as "Old M e t a i r i e " were
found to contain classic examples of corrosive attack and
related deterioration caused by hydrogen suIfide generated
in the sewage. This sewerage system and these conditions
constitute the subject and basis for this study.
The collection system and Helios pi ant (activated sludge)
had been completed in 1939. Soils in this area are gen-
erally soft to medium clays with silt and humus pockets
and sand lenses. Running sands are sometimes encountered
usually at depths below I 2 ft. The terrain is flat. These
conditions combine to dictate the use of minimal slopes
just adequate to maintain a velocity of 2 FPS and I imit
the practical depth to which a sewer can be; instal led to
about I 2 ft. The result is a large number of i i ft sta-
tions and force mains. The force mains constitute a
source of hydrogen suIfide and the gravity flow velocity
is generally inadequate to control sulfide buildup. The
He I ios Col lection System had a number of gravity I ines
carried to depths of 16 ft. These deeper sewers were in
extremely unstable soils and over the years developed
grossly uneven settlement and entrapment of sewage. Some
larger sewers, of unl ined concrete pipe, had col lapsed
or were found on the point of imminent collapse due to
corrosive attack of the crowns. S i rn i larly, a considerable
number of manholes, particularly where force mains dis-
charged into gravity sewers (discharge manholes), had
been severely attacked and several totally destroyed.
Streets had been undermined and the infiltration of sand
had completely overwhelmed the treatment plant's grit
removal facility. Except for short periods following a
heavy rain, sewage arriving at the plant was highly septic,
and treatment was virtually non-existant.
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In July of 1963, contracts aggregating in excess of $13
mill ion were awarded to implement the immediate phase of
the master plan. Approximately $11 mill ion was allocated
to new sewerage. Somewhat over $1 mill ion went to reha-
bi I itate the col lection system, and a I ike amount was used
to repair and update the treatment faci I ity. The obvious
and immediate needs in the col lection system imposed a di-
lemma. A number of major gravity I ines were beyond prac-
tical repair and had to be abandoned. The cost to remove
and replace these I ines was considered prohibitive, and
as a result the system had to be reconfigured with the add-
ition of new I ift stations and force mains.
The new configuration significantly reduced the overall
retention time of sewage in the system, improved veloc-
ities, and removed most, if not all, major sources of
septicity from the gravity portion of the system. Sewage
arriving at the plant was generally fresh. Odor at the
plant was abated and effective treatment restored. Off-
setting to some degree the marked improvement at the plant
was immediate evidence of sulfide generation in the longer
force mains and the stripping of hydrogen sulfide (HoS) in
the discharge manholes. The discharge manholes of two
force mains which generated the most complaints about odor
and which showed evidence of severe corrosive attack were
ultimately designated as Stations 5 and 7 in this study.
It is worthy of comment that the rehabilitation of the
system was completed in late 1964. In July of 1969 field
crews taking background samples for this study found both
discharge manholes at Stations 5 and 7 brought to the point
of imminent col lapse by corrosive attack. Over one inch
of mortar I ining had been consumed, no mortar was visible
between bricks in the upper two thirds of the manhole wall,
and bricks had fa I len from or could be removed with the
fingers from the top course.
Prior to appI ication by Jefferson Parish in March of 1968
for grant assistance from the then, Federal Water Pollution
Control Administration (FWPCA), to conduct this study,
there was clear recognition of the urgent need for effec-
tive control of sulfide generation in force mains, In-
vestigation of possible methods suggested that aeration
was by far the most feasible approach. In I ight of an
article published by Laughlin in 1964 (0, first con-
sideration had been given to aeration of the force main
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by injection of air immediately downstream of the pump
discharge. The City of New Orleans about this time began
a series of extensive experiments in this appI icat ion.
Observation of these efforts forced the conclusion that
air injection at the inlet of a long force main is feas-
ible only if the force main is specif ice. I iy designed over-
size with a steady upgrade from the point of air injection
to the discharge. The force mains in Jefferson Parish
were neither suited or practically adaptable to aeration
at the pump discharges.
Before^, abandoning aeration for a more costly chemical
treatment, attention was turned to the possibil
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and development grant under the Federal Water Pol Iution
Control Act as amended (466 et seq). On 27 June 1968
the Council accepted a FWPCA grant (WPRD-I 2 I-01(RI)-68).
The primary objective of this grant was to evaluate the
effectiveness of various full scale methods of in-sewer
aeration for reducing hydrogen sulfide problems and to
develop design data for future designs. Facilities con-
structed and evaluated included two aspirated air U-tube
systems for force main discharges, one in-I ine Venturi
aspirator and one in-I ine Vortex-Shear aerator in a force
main and one eductor or air-I ift pump installed in a
gravity sewer.
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SECTION IV
DESCRIPTION OF THE PROJECT
SELECTION OF TEST STATIONS
Figure I illustrates the configuration of the project and
the location of test stations on a portion of the street
map of the "Old Metairie" area of Jefferson Parish. A
schematic flow diagram of the test sewers showing the
aerator locations, sewers and approximate sewage flows
is shown in Figure 2.
Station I is a manhole in a 30" gravity sewer located
1200 ft upstream from the Hel ios Treatment Plant and 835
ft downstream of Station 2, The average dry weather flow
through Station I during the evaluation phase of the study
was on the order of 3.0 MGD which corresponds to a I iquid
depth of about 14 in. in the pipe. Surge effect from up-
stream force main discharges appear to be large I> damped
out at this station. Four untreated gravity laterals con-
tribute about .2 MGD or 7% of flow through Station I.
Accordingly with 937° of the flow through Station I from
the air-I i f t aerator instal led at Station 2 and 39/° of
this flow from the ll-tube at Station 5, Station ! was
considered to be a key samp I ing station in evaluating the
performance of the air-I ift aerator and the cumulative
effect of upstream aeration.
Station 2 is the location of the air-lift aeration device.
This is the only station in a gravity sewer. In the
original scope, Station 2 was spaced a calculated distance
downstream of aerators at Stations 5 and 15 on the basis
of a method proposed by C. L. Swanson (7). Ultimately
Station 15 had to be deleted to remain within available
funds. The spacing (2025 ft) downstream of Station 5 was
retained for Station 2 although the basis for the calcul-
ation was largely inval idated by the ommission of Station
15- The sewer at Station 2 is 30 in. and the dry weather
flow was on the order of 2-8 MGD during the evaluation.
Station 2 is located 185 ft downstream of the intercept
of two 2l in. sewers and 525 ft downstream of Station 13.
It is the unaerated flow of the 21 in. sewer from the
deleted Station 15 (see Figure l) that inval idatcd the
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•*• DELETED
FIGURE I-PLAN OF DEMONSTRATION SYSTEM
10
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LEGEND °
MeOU UNTREATED FLOW INTO AERATED SYSTEM
£j SAMPLE STATION LOCATIONS
(40^92^3^ PUMP STATION LOCATIONS
FM FORCE MAINS
9 GRAVITY SEWERS
(A) IN-LINE VORTEX-SHEAR ASPIRATOR LOCATION
MM IN-LINE VENTURI ASPIRATOR LOCATION
fYYVj VENTURI ASPIRATED "u" TUBE LOCATIONS
^2\ AIRLIFT AERATOR LOCATION
DEMONSTRATION SYSTEM SCHEMATK
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calculated spacing and which undoubtedly contributed to
the odor problem subsequently encountered. Approximately
I.3 MGD of the flow to Station 2 is from Station 13 with
upwards of I.0 MGD of this flow from the U-tube installed
at Station 5. Accordingly the ratio of treated to un-
treated sewage arriving at Station 2 was about 40-60. Be-
cause this station did not exist prior to installation of
the aeration device, and extreme turbulence occurred after
installation of the air-l ift aerator, Station 2 was not
considered a samp I ing station.
Station 13 is a manhole in a 2l in. gravity sewer located
1500 ft downstream of the U-tube instai led at Station 5.
Data from this station in conjunction with data from Sta-
tions 5 and 6 is the only basis for evaluating the cal-
culated spacing for aeration devices developed by this
demonstration. The average dry weather flow through
Station 13 during test hours is about I.3 MGD. Liquid
depth during sampling ranged between 9 in. and 14 in.
corresponding to flows of I and 2 MGD respectively.
Approximately 0.2 MGD of the flow through Station 13 is
from five untreated laterals entering the system down-
stream of Station 5 and I.I MGD from the U-tube at Sta-
tion 5 thus approximately 80% of each sample at Station
13 is from the U-tube installed at Station 5, and Sta-
tion 13 was selected to be the key sarnp I ing station in
the evaluation of U-tube performance as we I I as aerator
spac i ng.
Station 6 is the first manhole 370 ft downstream of Sta-
tion 5- This location was selected to evaluate the per-
formance of the U-tube at Station 5 because of the ex-
treme turbulence generated by the discharge from the 12
in. force main at Station 5 before installation of the
U-tube. The dry weather flow through Station 6 is about
I.I MGD. Of this flow about 0.05 MGD is from an 8 in.
untreated gravity sewer thus upwards of 95% of the flow
through Station 6 is from the U-tube at Station 5.
Station 5 is the discharge manhole for 3000 ft of 12 in.
force main from the pump station at Stations 30-40 and
is the location of the larger of two Venturi aspirated
U-tubes. The invert of the 12 in. force main into this
manhole is 7 ft 2 in. above the sewer invert. The fal I
and splash of this stream accounted for the stripping
of hS and a significant aeration at this station prior
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to diverting the flow through the U-tube. The pumping
rate through this U-tube averaged 1500 GPM during test
hours and dry weather. After adjustment of the controls
at Station 40, the duration of the pumping and off cycles
ranged between five and nine minutes depending on sep-
arate or simultaneous discharges from Stations 7 and 3! •
Flow through the U-tube at Station 5 averaged I.I MGD.
Taps were provided to determine pressure and to take
samples upstream of the U-tube.
Stations 30-40 are the dual wet wells of the pumping sta-
tion discharging to Station 5. Station 30 receives the
force main discharge from Stations 31-32- Station 40
receives the gravity discharge from Station 7. The two
wells are bottom connected by a 24 in- equalizer. The pump
suctions are installed in Station 40. Both Stations 30
and 40 had been sealed and provided with t> in. vents carried
under a rai I road embankment to an open area because of
continuing complaints about odor from residents in the
immediate vicinity. The force main discharge from Sta-
31-32 is relatively high. Prior to aeration the free fall
to the water surface in Station 30 was on the order1 of
4 ft at high water and 7 ft at low water. With the start
of the aeration devices, the high water level was raised
about 2 ft to prolong the pumping cycle. Low water re-
mained as previously set. As a consequence, there was
considerable turbulence in Station 30, both before and
after activation of the aeration devices. The average dry
weather flow through Stations 30-40 during test hours is
about I.I MGD. Of this, approximately .5 MGD is a fairly
uniform untreated flow from two 10 in. gravity sewers.
The flow from the U-tube at Station 7 was intermittent,
general ly 9 min out of 2 I at a rate of very nearly 0.7 MGD
or an average of just under .3 MGD. The flow from the
aeration device at Stations 31-32 was somewhat less fre-
quent, generally 5 min out of 24 at a rate approaching
I.4 MGD or again an average of just about .3 MGD. It can
only be assumed that a sample from either Station 30 or 40
taken near high water immediately after cessation of the
force main discharge would have between 40% and 857? of
aerated sewage depending on the separate or simultaneous
discharge of the two upstream stations. Because of the
questionable significance of samples from Stations 30 and
40, and the numerous complaints from residents in the
vicinity about opening the sealed covers at these stations,
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the taking of data after activation of the aeration devices
was minimal.
Station 7 is the discharge manhole for 2050 ft of 10 in.
force main from the pump station designated H53 on the
plan. It is also the location of the smaller aspirated
air U-tube. The pumping rate through this tube averaged
just under 600 GPM. The duration of pumping averaged 9 min
with an interval of 12 min between pumping.
Stations 31-32 are, respectively, pressure taps in the
force main immediately before and after the in-I ine Venturi
and Ashbrook Aerator located in an 8 in. force main 1220
ft downstream of pump station H52 and 300 ft upstream
of Station 30. The pumping rate through the aeration de-
vices ranged between 920 and 1080 GPM.
BACKGROUND DATA
The initial instrumentation for this project included 24 hr
clock operated samplers and battery operated recording
D.O. and temperature probes both purportedly sealed and
suitable for operation in the sewer atmosphere. After re-
peated failures and repairs during the first months of
samp I ing it became obvious that this instrumentation was
totally unsuitable and that the sampling procedure would
have to be revised. Reviewing available i nstrumentation
it was decided to use specific ion electrodes with extend-
ed leads for suIfide,chI oride and pH measurement directly
in the sewer stream. No rel iabIe data was col Iected dur-
ing the summer of 1968.
In early spring of 1969 it became apparent that design data
from Rocketdyne would not be received in time to permit
advertising and construction of the aeration devices in
time for evaluation that year. Field work was I imited
during 1969 to verification of sampl ing methods and proced-
ures. The taking of samples to establ ish background data
was initiated June 19, 1970 with the aeration devices
under construction and scheduled for activation in August
1970. Background data, viz: data accumulated prior to
activation of the aeration devices is tabulated on pages
86 thru 88 of Appendix B.
14
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AERATOR DESIGN AND INSTALLATION
Design criteria for the U-tubes and Venturi aspirators was
developed for this project by Rocketdyne under contract
14-12-434 with the FWPCA and is fully described in Rocket-
dyne Report entitled "U-Tube Aeration" (3)« Spacing of
the aerators was based on empirical methods developed by
C. L. Swanson (7). Prel imi nary design data was received
from Rocketdyne in May of 1969- it was immediately appar-
ent that the configuration developed by Rocketdyne for the
aspirated U-tube was vastly more sophisticated than had
been envisioned and would greatly exceed the estimated
cost, however, since a I I other aspects of the design were
complete including spacing of the devices, it was decided
to advertise for bids and, if necessary, either so) icit
additional funds or negotiate the el imination of certain
f ac i I i t i es to rema i n within available funds,
FWPCA and Louisiana State Board of Health approvals were
received in July of 1969 . On this
occasion two of four contractors submitted bids in Iine
with estimated cost and within budgeted Funds. The con-
tract was awarded to the low bidder, Pratt Farnsworth, Inc.
of Metairie, Louisiana. Construction was initiated in
March and completed in August of 1970.
It is worthy of comment here that the high bids initially
received from a I I contractors and subsequently from two of
the four bidding the readvertisement can be largely attrib-
uted to an understandable concern over the requirement to
sink 3 ft to 4 ft diameter casings for the U-tube to depths
of 50 ft in developed residential areas. In actual fact,
no problems were encountered and indications are that the
casings could have been extended to considerably greater--
depths without difficulty.
The U-tube has three characteristics essential to effective
transfer. First, pressure resulting from a head of water;
second, a homogenous dispersion of air as bubbles due to
vertical flow; and third, an extended contact time due to
the inherent rise rate of the bubbles opposing the direction
15
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of an only si ightIy greater rate of I iquid flow in the
down leg of the tube,
The Venturi aspirated U-tubes as installed at Stations 5
and 7 are iIlustrated in Figures 4 through 7. The Venturi
is shown in Figure 3. Basic design objectives and con-
straints include:
a) A Venturi throat pressure below ambient to aspirate
the required volume of air; in this demonstration to
realize an air/water volume ratio on the order of O.I.
b) A smooth flow I ine that wi I I freely pass stringy ma-
ter i a I .
c) A Venturi throat diameter that wi I I pass a 3 in. or
in some cases 4 in. diameter sphere. In this demon-
stration 4 in. was used.
d) A down leg diameter that wi I I produce the minimum
velocity adequate to maintain optimum entrainment of
the air bubbles. In this demonstration a value
between I.5 and 2.0 FPS was used based on experiment-
al work by Rocketdyne (3).
e) A return bend and up leg diameter that wi I I insure a
velocity adequate to transport grit and larger solids
I ikely to be encountered in sewage, in this demon-
stration 4 FPS.
f) A casing of maximum practical depth to increase pres-
sure within the U-tube and enhance oxygen transfer.
In this demonstration the target depth was 50 ft and
actual depth real ized 43 ft and 57 ft for Stations 5
and 7 respectively.
g) The maximum vertical distance obtainable between the
center I ine of the Venturi and the center I ine of the
U-tube discharge. In this demonstration dimensions
of 9.5 ft and 7.0 ft were used for Stations 5 and 7
respectively. This dimension will significantly effect
the total head loss through the system and consequent-
ly Venturi design.
PVC, suitably reinforced with fibreglass, was selected for
construction of the U-tubes.
16
-------
/ o
o
SECTION
I ASPIRATION INLET
2 ASPIRATION PORTS • SPECIAL DRILLING
3 UPSTREAM TAP-STANDARD DRILLING
FIGURE 3-DETAILS OF VENTURI ASPIRATORS
-------
FORMER
DISCHARGE
8 GRAVITY
UPSTREAM
SAMPLING TAP
STATION 5B
VENTURI
ASPIRATOR
U-TUBE DISCHARGE
DISCHARGE MANHOLE
STATION 5A
21" GRAVITY
FIGURE 4-PLAN OF U-TUBE AT STATION 5
-------
FIGURE 5-ELEVATION OF U-TUBE AT STATION 5
-------
10'
10" GRAVITY-
jt^UPSTREAM TAP
VT STATION 7B
.VENTURI
ASPIRATOR
DISCHARGE MANHOLE
/ STATION 7A
FIGURE 6-PLAN OF U-TUBE AT STATION 7
20
-------
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FIGURE 7 -ELEVATION OF U-TUBE AT STATION 7
21
-------
Taps were provided to permit pressure readings at the
Ventur i throat, after the Ventur i, at the top of the down
leg, at the bottom of the down leg, at the bottom of up
leg and at the top of the up leg. There is also pro-
vision for metering the aspirated air to the Venturi
throat. The original configuration provided a rel ief
col Iar at the entrance to the U-tube (see Figure 8).
This collar released entrapped air from the down leg then
sealed as syphon action was establ ished. This seal was
removed the first week in November 1970 and the U-tube
piped sol id to the Venturi in an unsuccessful attempt to
increase the volume of air aspirated. A final modification
in November of 1971 (see Figure 9), also aimed unsuccess-
ful I y at boosting the volume of air aspirated, shifted
the increase from Venturi outlet size to down leg diameter
from ahead of to after the entrance elbow.
The steel casings for the U-tubes were jetted down, open
ended, using hydrant pressure with occasional Iight driving,
then cleaned by jetting and pumping, maintaining the casing
fuI I of water at al I times to resist soi I pressure at the
bottom. The U-tubes were sunk
and maintained fuI I of water wi
during placement of concrete.
means of a tremie with a 6 in,
the U-tube in about 4 ft lifts,
six yard load filling 25 ft of
in the water fi I led casings
th si ight positive pressure
Concrete was placed by
tube on alternate sides of
At Station 5 the first
the casing was placed with-
out incident. When placement of the second load was
started an hour later several feet of defective seam open-
ed in the down leg just above the 25 ft level. About half
a yard of the second pour entered the U-tube plugging it
sol idly. This necessitated replacing the U-tube and sink-
ing the 48 in. diameter casing now half filled with con-
crete to a depth of over 75 ft to permit instal I at ion of
a new 50 ft U-tube. The operation was stopped at 68 ft
when low pressure jetting became ineffectual,
The tube length was reduced to 43 ft. It is apparent from
this experience that open ended casings can practically
and economical ly be sunk to depths we I I in excess of 50 ft
in these soils, even in fully developed residential areas
as was the case in this demonstration. No problems were
encountered at Station 7 with the depth increased to 57 ft.
The Venturi aspirators employed with the U-tubes are essen-
tial ly standard Dal I flow tubes, product series 121 as
22
-------
NEOPRENE DIAPHRAGM
PRESSURE RELEASE
VACUUM SEAL
ORIGINAL ENTRANCE ELBOW
SEALED WITH
FIBREGLASS
INTERIM MODIFICATION
FIGURE 8-ORIGINAL U-TUBE ENTRANCE ELBOW
AND INTERIM MODIFICATION
23
-------
SUPERCHARGING
CONNECTION
SUPERCHARGING PORTS
CLEAR ACRYLIC TUBE
VENTURI
DOWN LEG OF U-TUBE
FIGURE 9 - FINAL MODIFCATION TO U-TUBE
ENTRANCE ELBOWS.
24
-------
manufactured by BIF. These "tubes were modified by drill-
ing additional ports to augment aspirat ion as illustrated
in Figure 3•
The in-line Ventur i asp i rator i nstaI Ied at Stat i on 31 and
shown in Figure 10 is basically similar to those applied
to the ll-tubes, but i nsta I led 300 ft from the discharge of
the force main. The 300 ft of pipe downstream of the
Ventur i replaces the ll-tube as a reaction chamber. As in
the case of the U-tubes, the vertical distance from the
center I ine of the Venturi to the center! ine of the force
main discharge is critical. By locating this Ventur i
4 ft 0 in. above grade at Station 31, a total drop of I 2
ft to the force main discharge in Station 30 was realized.
Also instaI led at Station 31 and shown in Figure 10 is
an Ashbrook "Inl inator". This is a patented device oper-
ating on the Vortex-shear diffusion principle offered by
the Ashbrook Corp. of Houston, Texas in a variety of stan-
dard sizes and configurations. The 1000 GPM unit install-
ed in this demonstration involved reduction from the 8 in.
force main to a 4 in. inlet nozzle arid, according to the
manufacturer, required an upstream pressure of from 15
to 20 psig. In operation the upstream pressure was 13 psiy
with a flow of 910 GPM. In this regard, the Ashbrook
device does not compare favorably with the Li-tube and in
this demonstration failed to aspirate. A brief experiment
in which air from high pressure bottles was injected at
30 psig immediately upstream showed a transfer of 4 mg/I
D.O. Since the Ashbrook would not aspirate and since the
continued injection of air from bottles would have been
impractical and costly, no further evaluation of this de-
v i ce was made.
The aeration device installed at Station 2 and illustrated
in Figure II is a modified air I i f t pump designed to acco-
modate the f u I I flow of the sewer with a I i f t of" 2 ft 6 in.
The incoming sewage flows down the casing/ is air I ifted up
the riser and discharged into the leaving gravity sewer .
The 2 ft 6 in. lift was provided only to permit a support
system clear of the flowing stream so that stringy mate-
rials would not be trapped. This proved to be a mistake
and undoubtedly contributed to the stripping of hydrogen
sulfide that rendered this configuration of an air I ift
unacceptable. Otherwise performance was excel lent. The
air I ift concept, if the stripping of HoS can be control led
still appears to be the best compromise for aeration at
25
-------
I ASHBROOK AERATOR
2 VENTURI AERATOR
3 UPSTREAM TAP
4 DOWNSTREAM TAP
FIGURE 10-PLAN OF STATION 31
26
-------
to!
i
-------
selected points in an existing gravity sewer at locations
other than force main discharges. The airl ift permits
injection of the air at almost any depth to optimize
oxygen transfer. This configuration uses a casing depth
of 20 ft. The requirement to maintain a velocity of 4 FPS
in vertical risers is obviously detrimental from the stand-
point of retention time if a strictly conventional air-
I ift is used. Accordingly the airl ift for this demonstra-
tion was modified to provide for injecting aeration air
into the casing or down leg I I .5 ft below the operating
water level and 8.5 ft above the bottom of the casing.
With a 24 in. casing and a 14 in. I ift pipe, the down leg
velocity in this case was roughly I.6 FPS opposed to a
bubble rise rate taken at .8 FPS or a net bubble travel
rate of .8 FPS. Thus, retention time in the maximum pres-
sure zone below I I .5 ft was approximately 12 seconds.
The volume of air required in a conventional airl ift can
be approximated from the equation V=H/250 Log ((S+34)/34)
where V^voIume of air in cubic feet per gal Ion of water,
H=the I ift above operating water level in feet and S=
submergence below operating water level in feet. The
optimum air/water volume ratio for oxygen transfer was
taken at something less than .20. Higher ratios were not
necessary to supply the required oxygen and would present
the possibiI ity of slug flow rather than the desired even
dispersion of small bubbles, Accordingly this application
is modified by injecting air to a maximum of 20% by vol-
ume 11.5 ft below operating water level. The effective
submergence is taken to be I I .5 ft with a s.g. of I .0 plus
8.5 ft with an s.g. of .8 or 18-3 ft in lieu of 20 ft.
With a lift of 2-5 and a Q of 1500 GPM, the volume of lift
air required is 2.5/(250X.I 875) or .053 CF/Gal. and 1500 x
.053 = 79.5 CFM. Aeration air required is 20% and 1500/7.48
X .2 = 40 CFM. Total air required = 119.5 CFM. The start-
ing head for this airI ift is 20 ft HoO or 8.87 psig.
No problem was encountered in sinking the aerator casing
which could and as events subsequently demonstrated prob-
ably should have been sunk to at least 50 ft to increase
the contact time under increased pressure for greater trans-
fer of oxygen into the sewage stream. One comment is in
order about operation. Aeration air must be admitted after
the I ift is in operation and then with caution as this air
is entering against a significantly lower pressure than
28
-------
the I ift air and excess air in the down leg will render the
air I ift inoperable. A sensitive control valve for accur-
ate metering of aeration air is essential.
The aerator at Station 2 was spaced in relation to the
aerator at Station 5 with the objective oi maintaining a
residual D.O. of 1.0 mg/I in the sewage. No basis per se
for calculating the required spacing of aeration devices
in a sewer system could be found in pub I ishecl I iterature.
However, on the basis of existing publications on sulfide
production and control, Mr. C. L. Swanson, the LPA Project
Officer at the time, developed and submitted an empirical
method (7) for approximating the required spacing of aera-
tion devices. This method was employed in locating Station
2 with relation to Stations 5 and I.1) in the original scope
of this project. Unfortunately, it was necessary to delete
a number of stations including Station 15 to remain within
ava i IabIe funds.
Because of the el imi nation of Station 1.5 and the entry of
the untreated 21 in. stream from Station 15 between Sta-
tions 2 and 13, Stations 5A and 1,3 were selected to eval-
uate this method for calculating the required spacing of
aeration devices. A discussion and evaluation of Swanson's
method (7) for calculating required spacing of aeration
devices in contained in Section Vl of this report.
The actual installed cost of the several aeration devices
is tabulated below:
St at i on 5 - Aspirated air li-tube instal led on the end
of a I 2 in. force main. Flow = 1700 GPM, depth r-
43 ft. Installed cost - $16,000.00.
Stat i on 7 - Aspirated air U-tube instal led on the end
of an 8 in. force main. Flow - 650 GPM, depth =
57 ft. Installed cost - $11,000.00.
Stat i on 31 - Venture aspirator installed in an 8 in.
force main. Flow = 1000 GPM. Installed cost -
$7,000.00.
Ashbrook aerator installed in an 8 in. force main.
Flow = 1000 GPM. Installed cost - $9,000.00.
29
-------
Stat i on 2 - Eductor or air-l i f t pump instal led in a
30 in. gravity sewer. Maximum and average dry weather
flow = 2000 GPM and 1500 GPM, respectively. Installed
cost - $13,000.00.
TEST PROCEDURES
Readings of temperature, flow, pH, D.O., BOD^, COD and
sulfides were taken at the selected stations shown in Fig-
ures I and 2 before and after aeration. Additional read-
ings of immediate oxygen demand ( I OD ) and D.O. were taken
before and after each aeration device.
D.O. and I OD measurements were made using the Azide modifi-
cation of the Winkler Method. I OD samples consisted of
100 ML of sewage diluted with 200 ML of aerated distilled
water in a standard 300 ML BOD bottle. DO measurements
were made five and ten minutes after combination. I OD was
determined by the f o I lowing equation:
IOD = 300 DO - 200 D0
oo
where D0| is the DO of the mixed 300 ML sample and D02 is
the DO of the di lution water, usual ly at or near satur-
ation.
COD determinations were made per Standard Methods (4) using
the dichromate reflux method.
BOD5 determinations were made per Standard Methods .
Pressure drops and air aspiration rates for the Ventur i
and Ashbrook devices were recorded. Final ly, pressure read-
ings were taken by personnel from Rocketdyne to determine
actual head losses through the U-tube. Head loss data
through the U-tube has been compiled and reported by Rocket-
dyne in their report on "U-tube Aeration" (3). Samples for
determination of D.O., IOD, BOD^, and COD were taken in
standard 300 ML BOD bottles. The bottles were either im-
mersed in the stream or f i I led from pressure taps with
hoses extending to the bottom of the bottle to minimize
aeration in sampl ing. For BODc and COD determination, the
completely filled bottles, free of air bubbles, were sealed
and packed in ice for transport to the lab. D.O. and IOD
determinations were run in the field.
30
-------
pH and sulfide determinations were made using electrodes
either in stream or in a plastic beaker at the pressure
taps. In the latter case, a hose extended to the bottom
of the beaker which was filled and slowly overflowed with
the electrodes immersed we I I below the surface. The pH
electrode used was Cornings No.476027. The sulfide elec-
trode was Orion Model 94-16. The reference electrode in
both cases was Orion 90-02. Orion Specific Ion Meters
Models 404 and 407 were used for suI fides and pH respect-
ively. The Orion 94-16 sulfide electrode is represented
by the manufacturer to be essential iy interference free
and capable of stable readings down to a sulfide concen-
tration of 10"' moles per I iter. The- electrode develops
a potential proportional to the activity of the sulfide
ion in the sample. The electrode does not respond to
bound or cornp I exed su I fides, however with pH and ionic
strength known, the total dissolved suI fides (the sum of
h^S, HS~ and S~) can be computed. This relationship is
shown in Figure I 2. The electrode responds only to sulfide
ion (S=) and in this demonstration within the shaded band
on Figure I 2.
In domestic sewage with a pH at or below 8, ionic strength
is not too significant and need only be approximated. For
example, if an ionic strength of 10-3 moles per I iter is
assumed, then variations in ionic strength over the fuI i
range of I0~~ to 10"^ rnoles per I iter would introduce an
error of 6% or less in the determination of total suif ides.
On the other hand, for any ionic strength in the range of
10-4 to I 0 ~^ moles per liter, a variation be tweet; a pH of
6 and 8 represents a range of roughly three powers of ten
in sulfide ion activity and extreme accuracy in the measure
of pH is essential.
Since high dosage with NaCI was involved in this demonstra-
tion in determining time of travel (detention time), ionic
strength (I.S.) was programmed on the basis of measured
chlorides with:
I.S. = CL-(mg/l)/35457
The above formula empiricalIy converts mg/i CL~ to solution
31
-------
FIGURE 12-LOG FRACTIONS OF DISSOLVED SULFIDES
32
-------
ionic strength in moles per liter. The result in the case
of NaCI is identical with that derived by converting mg/l
CL- to mg/l NaCI then computing mg/l Na and applying the
formula: ionic strength = 2 I Z.^C. After dosage with NaC I
was terminated measurement of chloride concentration was
discontinued. The average value of background chlorides
(200 mg/l) was assumed for all subsequent sulfide measure-
ments, i.e. an ionic strength of 5.6 x 10-3 moles per
liter. To verify the above formula a composite sample was
made up of six samples taken hourly at Station I on July 16,
1970. Chlorides were measured in stream concurrently with
the individual samples. The conductivity of the composite
sample was 580 micromhos equivalent roughly to an ionic
strength of .007M. The average of the six chloride measure-
ments was 236 rng/l and 236/35457 = .0066M. All pH measure-
ments were read to two decimal places. This is welI with-
in the capabiI ity of the Orion 407 which has an expanded
pH scale with a full scale deflection of 2.
With the exception of the Orion 90-02 reference electrode,
no problems were encountered in this instrumentation. These
reference electrodes appear to be somewhat vulnerable to
the sewer environment, and required constant verification
and frequent rep Iacement of the outer f i I I i ng so i ut i on
(I 0% KNO^). Since the same reference is used with both the
pH and sulfide electrodes, the stability of the reference
electrode can be verified with standard pH solutions,
it is worthy of comment that the Orion 404 meter can be
calibrated in the lab for direct readout of total suIf ides,
using sulfide standards, however, standards for field ver-
ification would have to be at or above a pH of 13 to be
reasonably stable. At pH 13 the resulting potential is in
the vicinity of -800 MV which is beyond the maximum (-700
MV) scale of the 404-
In this demonstration, the sulfide electrode was cal ibrated
in the lab using an Orion Model 801 meter which has a range
of -999-9 to +999.9 MV and standard sulfide solutions of
.001, .01 and .1 mg/l all at a pH above 13. The calibra-
tion was incorporated in the computer program (Appendix A)
which was used to calculate total dissolved suI fides from
the field measurements i n absoIute m i I I i voIts us i ng the
sulfide electrode and the Orion 404 meter.
33
-------
Like any biological function, the generation of sulfides
is temperature dependent, and since the purpose of this
demonstration is to evaluate the effects of aeration on
sulfides, the effects of temperature must be accounted for
by standardization to a base temperature. For this demon-
stration, a base temperature of 85° F was selected since
this was the average of alI sewage temperatures before
activation of the aeration devices. All instream sulfide
measurements have been standardized to 85° F by applica-
tion of the formula:
S85 = S(I.09385-T),
where S • total dissolved sulfides as computed from in-
stream measurement of sulfide ion activity units and T =
the instream temperature, °F. This formula evolves from
observations by Baumgartner (5) and subsequently by Pomeroy
and Bowl us (6) that rate of sulfide generation in sewers
increases about 3-9% per degree F rise in temperature be-
tween I imits of 60° F to 100° F. The extreme range in
this demonstration was 76° F to 89° F.
In this demonstration, the determination of total dissol-
ved sulfides is based on measured pH, absolute MV S~ and
temperature. The program (for the IBM 1130) to compute
total dissolved sulfides for this input is described in
Append ix A.
34
-------
SECTION V
RESULTS
TEST STATIONS
Recapping briefly, Stations I, 13, 6 and 40 are the key
downstream sampl ing stations, I isted in order of progress-
ion upstream from the downstream terminal as previously
shown in Figures I and 2- Station I, the downstream term-
inal is approximately 835 ft downstream of the air-l ift
aerator at Station 2- Station 2 is located 525 ft down-
stream of Station 13 and 185 ft downstream of the inter-
cept of the sewer from Station 13 and an untreated sewer
of roughly equal flow. Station 13 is 1500 ft downstream
of the U-tube aerator at Station 5- Station 6 is 370 ft
downstream of Station 5. Station 40 is the wet we I I of the
I ift station pumping to Station 5 through 3000 ft of I 2
in. force main and is 400 ft downstream of the U-tube at
Station 7• The U-tube at Station 7 is installed on the
discharge end of 2050 ft of 10 in. force main. Stations
2, 5B and 7B did not exist prior to the installation of
the aeration devices. Station 2 is the air-lift aerator.
Stations 5B and 7B are pressure taps in the force mains
immediately upstream of the U-tube Venturi aspirators lo-
cated at Stations 5 and 7. No readings were made at
Station 5 before installation of the aeration devices be-
cause of extreme turbulence and complaints of odor from
residents in the vicinity. Station 6, 370 ft downstream
from 5 with nominal velocities and no turbulence is the
sampl ing station selected to evaluate the performance of
the U-tube installed at Station 5- Measurements had to be
taken at Station 7A, the discharge manhole at Station 7,
both before and after activation of the U-tube despite the
fact that this manhole had considerable turbulence before
installation of the U-tube and contained upwards of 30%
unaerated sewage after activation of the U-tube. This was
because velocities in the one downstream manhole between
Stations 7 and 40 were found to exceed 5 FPS and made
sampl ing and instream measurements impossible.
RAINFALL AND TEMPERATURE BACKGROUND
Figure 13 is an hourly plot of maximum and minimum instream
and air temperatures over the test period. Minimum
35
-------
100-
OJ
o\
CO
Ul
Ul
K
<9
UJ
O
70-
60-
50-
40-
30-
MIN. STREAM
12 I 2 34 5 « 78 9 IO II 12 I 234 5 6789 10 II
NOON
FIGURE 13- INSTREAM AND AIR TEMPERATURES
-------
temperatures were generated entirely in the last two days
of the project and relate only to measurements taken at
Station I on November 5th and 6th. These are the only days
during the test period when instream temperatures below
80° F were recorded. Tests were terminated when instream
temperatures dropped to 76° F on November 6th. Figure 14
is a daily pIot of ra i nfa I I and resu11 i ng system d i Iut i on
during the test period.
The curve from Figure 14 is included as an approximate in-
dication of the percent dilution on all daily plots of
sulfides, D.O., BOD5 and COD. The dry weather flow to the
plant averages 5-5 MGD. Daily flows significantly above
5.5 are the result of rainwater infiltration. The bar
graph on Figure 14 gives the daily occurrence and duration
but not the intensity of significant rains during the test
period. The curve on Figure 14 represents the totalized
daily flow to the treatment plant. Maximum pumping cap-
acity at the treatment plant is si ightly in excess of 10
MGD. Normal or dryweather flow is about 4 MGD for 24 hrs
but at a rate of about 5.5 MGD during test hours. A plot
of 10 MGD, therefore, indicates continuous pumping at
maximum capacity for the entire 24-hour period and a dilu-
tion of 150%. At anything above 7 MGD the entire system
would be heavi ly surcharged and no instream measurements
or samp I ing would be attempted. Samples and measurements
were generally taken only when flow in the system was near
normal with gravity sewers not significantly more than half
fuI I . It is obvious, however, from the amount of rain en-
countered throughout the test period that some degree of
residual dilution figures in a good percentage of the
measurements. The effect, both immediate and residual, of
rainwater dilution is apparent in a tendency of the various
parameters to track the dilution trace.
ANALYTICAL TESTING
One thousand eighty-nine (l,089J instream measurements
were made at the seven test stations over the period
July 2, 1970 to August 7, 1970 before activation of the
aeration devices. On August 8, 1970, aeration devices
were activated at aerator installations, Stations 2, 5, 7
and 31. Subsequently, twelve-hundred thirty-six (1,236) in-
stream measurements were made at nine stations over the per-
iod August II to November 6, 1970. A tabulation of all
37
-------
OJ
oo
1970
o
o
oc
UJ
Q.
-------
instream readings is included as Appendix B to this report.
To give meaningful results, alI instream sulfide measure-
ments used in the plots and tabulations have been standard-
ized to 85° F as previously described.
AIRLIFT AERATOR
Station I is the downstream terminal of this demonstration
and reflects both the performances of the air I ift aerator
instal led at Station 2 and the cumulative effect of a I I up-
stream aeration devices. 93% of the flow through Station I
is from the air I ift aerator at Station 2 and 37% of the
flow had additionally been through the U-tube at Station 5.
Figure 15 is a daily plot of D.O. at Station I, the down-
stream terminal. No measureable D.O. was recorded at this
station before activation of the aeration devices. After
the aeration devices were activated, a residual D.O. was
always evident ranging from a low of 0.2 mg/I to a high of
3.8 mg/l and averaging I .4 mg/l .
Figure 16 is the daily plot of suI fides at Station I. Dis-
solved suIfides (Sgr) were consistently present at Station
I before activation of the aeration devices, ranging from
a low of 0.03 mg/l to a high of 3.45 mg/l, and averaging
0.63 mg/l. After activation of the aeration devices 40
measurements were made. Only three of the 40 measurements
showed traces of sulfide (.01 mg/l, .04 mg/l and .09 mg/l).
In the remaining 37 measurements no sulfide was detected.
Figure 17 is the hourly plot of 69 dissolved sulfide mea-
surements taken at Station I (29 before and 40 after acti-
vation of aeration devices). Figure 18 is the daily plot
of BOD^ and COD run on samples taken at the same time su i -
fides were measured at Station I. Before activation of the
aeration devices, BODc ranged from a low of 48 mg/l to a
high of 334 mg/l with an average of 169 mg/l. COD ranged
from a low of 158 mg/l to a high of 554 mg/l with an aver-
age of 310 mg/l. After activation of the aeration devices
BOD5 ranged from a low of 42 mg/l to a high of 281 mg/l
with an average of I 28 mg/l and COD ranged from a Iow of
117 mg/l to a high of 304 mg/l with an average of 208 mg/l.
The indicated reduction attributable to in-line aeration
was 100% for dissolved suI fides, 24% for BODr and 33% for
COD.
39
-------
1970
UJ
?
X
o
o
Ul
8
o
-I
•s.
o
Ul
O
(E
JUNE
20 25
0
150
100
50
JULY
AUG
4
-e—• OPO o
BEFORE AERATION
AUG.
10 15 20 25
SEPT.
10 IS 20 25
OCT.
5 10 15 20 25
I ! I I T
cP
o
o o
AFTER AERATIOM
oo
o
NOV.
-f-
o
o
§
FIGURE 15- DISSOLVED OXYGEN AT STATION I.
-------
1970
Q
UJ
3
O
8
O
UJ
O
tr
UJ
Q.
JUNE
20 25
0
ISO
100
50
.JULY
5 10 15 20 25
AUG
4
BEFORE AERATION
AUG.
10 IS 20 25
TTI
SEPT
5 10 15 20 25
OCT.
NOV.
?
AFTER AERATION
FIGURE 16- DISSOLVED SULFIDES AT STATION I.
-------
to
CO
UJ
Q
J*l
CO
o
Ul
o
JJJ
5
_i
&
2
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
; BEFORE AERATION (0)
AFTER AERATION (X)
-
-
-
•
•
—
: o
~ 0
'- 0 ° ° 0
o
'. o o o o
O r\
1 o O x"xxx xxxxSx xxxxxxxxxxxxxx x°P
1 ' 1 ' 1 ' 1 ' 1 ' 1 ' 1 ' I ' 1 ' 1 ' 1 ' I ' 1 ' 1
789 10 II 12 1 2345678
A M TIME OF DAY PM
FIGURE 17 -DISSOLVED SULFIDES AT STATION 1.
-------
1970
Ul
o
UJ
<9
X
o
o
H
z
a:
H
JUNE
2O 25
500
400
300
ZOO
100
0
ISO
too
50
JULY
AUG
o
I
»
0
8
J
A o
o §
BEFORE AERATION
AUG.
JQ 15 20 25
SEPT.
5 10 15 20 25
"1f i r I
OCT.
5 10 15 ZO 25
» i i i T
NOV.
-4-
X
o
X
o
X
o
* X
X
o
QD
AFT£R AERATION
0-BOD,
X- COD
FIGURE 18 - BOD5 AND COD AT STATION I.
-------
U-TUBE EVALUATION
Station 13 is a manhole 1500 ft downstream of the discharge
of the U-tube at Station 5. 79% of the flow through Sta-
tion 13 is from the U-tube at Station 5 and the remainder
from untreated gravity laterals. Figure 19 is the daily
plot of D.Q. at Station 13 before and after activation of
the aeration devices. Before activation of the aeration
devices, 15 of 23 D.O. measurements registered 0. The
highest D.O. recorded was 0.4 mg/l and the average of the
23 measurements was 0.01 mg/l. After activation of the
aeration only two of twenty-seven D.O. measurements re-
gistered 0. The highest D.O. was 2.1 mg/l and the aver-
age of the 2? D.O. measurements was 0.7 mg/l. Figure 20
is the daily plot of dissolved sulfides (Sor) at Station
13. Before activation of the aeration devices, in only
one of 24 measurements was there no detectable sulfides.
Dissolved sulfides ranged from this one zero measurement
to a high of I .3 nig/I with an average of 0.30 mg/l . After
activation of the aeration devices there was no measurable
sulfides in 16 of 24 measurements. There was one reading
of 0.23 mg/l, all other measurements were below 0.10 PPM
and the average of the 24 measurements was 0.02 mg/l dis-
solved sulfides (Sg5). The apparent reduction in dissolved
sulfides at Station 13 attributable to aeration was 93%*
Figure 21 is the hourly plot of 48 sulfide measurements
at Station 13 (24 before and 24 after activation of the
U-tube at Station 5). Figure 22 is the daily plot of BOD5
and COD at Station 13 run on samples taken at the same
time sulfide measurements were made. Before activation
of the aeration devices BODr ranged from a low of 53 mg/l
to a high of 458 mg/l with an average of 176 mg/l. COD
ranged from a low of 96 mg/l to a high of 634 mg/l with an
average of 315 mg/l. After activation of the aeration
devices BOD^ ranged from a low of 36 mg/l to a high of
308 mg/l with an average of 150 mg/l. COD ranged from a
low of 161 mg/l to a high of 408 mg/l with an average of
250 mg/l. Based on the average values, the apparent re-
duction attributable to aeration was 2\% for COD and 15%
for BOD5.
Station 6 is the first manhole 370 ft downstream of the
discharge of the U-tube at Station 5. Based on measure-
ments at time of sampling, the fraction of aerated sewage
through this station averaged 96%. Figure 23 is the plot
44
-------
Ul
1970
UJ
<9
i
o
UJ
8
o
I-
J
o
UJ
o
cr
ui
Q.
JUNE
20 23
0
ISO
100
50
JULY
oo o
AUG
4
08
n
O O
BEFORE AERATION
AUG.
10 15 2O 25
SEPT.
10 15 20 25
OCT.
10 15 20 25
III!
O
o
-8-
o
o
0°0
AFTER AERATION
NOV.
FIGURE 19- DISSOLVED OXYGEN AT STATION 13.
-------
a\
1970
V)
UJ
Q
Z)
CO
Q
Ul
O
co
CO
ID
_J
Q
UJ
O
DC
UJ
OL
JUNE
20 25
2
I
0
150
IOO
50
JULY
AUG
4
BEFORE AERATION
AUG.
10 15 20 25
SEPT
5 10 15 20 25
—^—^—i^—^^^^—^^^B^M—^pnB
OCT.
5 10 15 20 25
i i I i T
NOV.
AFTER AERATION
FIGURE 20-DISSOLVED SULFIDES AT STATION 13
-------
CO
uT
_j
t/t
if*
Q
Ul
CO
S
_j
X
o
*
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
: BEFORE AERATION (0)
•_ AFTER AERATION (X)
-
-
-
-
—
-
.
~
-
-
.
[ O
r o
: o o
~~ « o
o o
° O H n 0
O a 8°
* c* PP A» SM *****&** *
I ' 1 ' 1 ' 1 ' 1 ' 1 ' I ' 1 ' 1 ' I ' I ' I ' 1 ' 1
789 10 II 12 1 2345678
A-M- TIME OF DAY ™
FIGURE 21- DISSOLVED SULFIDES AT STATION 13.
-------
OO
1970
o
UJ
o
UJ
o
g
Z
O
_J
O
Ul
O
(T
UJ
QL
JUNE
20 23
500
40O
30O
200
IOO
0
150
IOO
50
JULY
* X
X X
6
o
o
AUG
4
O X
* C
BEFORE AERATION
AUG.
10 IS 20 25
SEPT
10 15 20 25
OCT.
5 10 15 20 £5
I I ! | T
NOV.
o
xx
§
o
X
o
X
X
°6
0- BODp
X- COD"
AFTER AERATION
FIGURE 22- BOD. AND COD AT STATION 13 .
-------
D.O. measurements recorded at Station 6 before and after
activation of the aeration devices. The aeration re-
sulting from the seven foot fa I I from the force main into
Station 5 before installation of the U-tube is clearly
evident. Only five of thirty-two measurements showed no
D.O. The high was 2.1 mg/I and the average of 32 measure-
ments was 0.8 mg/l. After installation of the U-tube
which eliminated the seven foot fall, D.O. at Station 6
ranged from a low of 0.6 mg/l to a high of 2-8 mg/l with
an average of I.6 mg/l. Figure 24 is the daily plot of
dissolved sulfides at Station 6 before and after activa-
tion of the aeration devices. Before activation of the
aeration devices only three of thirty-two measurements
showed no measureable sulfides. The high of 6.0 rng/l was
the highest concentration of dissolved sulfides recorded
in the demonstration. The average of the 32 measurements
was 0.51 mg/l dissolved sulfides. After activation of the
aeration devices, dissolved sulfides at Station 6 ranged
from zero to a high of 0.18 mg/l with an average of 0.05
mg/l. The apparent reduction in dissolved sulfides (Sec)
attributable to aeration was 90%. Figure 25 is the hourly
plot of 41 measurements of dissolved sulfides. Figure 26
is the daily plot of BODr and COD run on samples taken at
the same time sulfide measurements were made, before and
after activation of the aeration devices at Station 6.
Before activation of the aeration devices, BODr ranged from
a low of 33 mg/l to a high of 285 mg/l with an average
of 151 mg/l• COD ranged from a low of 75 mg/l to a high
of 539 mg/l with an average 296 mg/l. After activation
of the aeration devices, BODr ranged from a low of 28 mg/I
to a high of 294 mg/l with an average of I 28 mg/l and COD
ranged from a low of I 23 to a high of 529 mg/l with an
average of 260 mg/l. The apparent reduction at Station 6
attributable to aeration was I 2% for COD and \7% in BOD.
Station 5 is the location of the larger of two Venturi
aspirated U-tubes. Before installation of the U-tube, a
12 in. force main discharged into the manhole, designated
5A in Figure 2, with a seven foot fa I I from the invert of
this force main to the invert of the receiving 21" gra-
vity sewer. 2400 ft of 8 in. gravity sewer with its in-
vert set 0.4 feet above the invert of the 2l in. sewer
also discharges into 5A. The invert of the 12 in. U-tube
discharge was set O.I feet above the invert of the re-
ceiving sewer, consequently with the activation of the
U-tube, the seven foot fa I I of the force main discharge
49
-------
1970
UJ
o
X
o
o
Ul
3
o
CO
CO
a
o
UJ
O
tr.
JUNE
2O 25
0
ISO
IOO
50
JULY
AUG
4
0 O
AUG.
10 15 20 25
SEPT.
5 10 IS 20 25
' i ' ' i
OCT.
5 10 15 20 25
i i i i i
NOV.
o
o
8
BEFORE AERATION
AFTER AERATION
FIGURE 23 - DISSOLVED OXYGEN AT STATION 6.
-------
1970
co
e
u.
to
0
Ul
o
CO
CO
5
_J
Q
Ul
o
cc
JUNE
ZO 23
0
ISO
IOO
50
0
JULY
AUG
BEFORE AERATION
AUG.
10 15 20 25
T T I
-e e-
SEPT
10 15 20 25
OCT.
5 10 15 20 25
i T i r T
NOV.
AFTER AERATION
FIGURE 24- DISSOLVED SULFIDES AT STATION 6
-------
CO
g
u.
••J
CO
o
UJ
2
CO
CO
Q
_J
\
O O* xQ^i GIJ O O
1 ' 1 ' 1 ' 1 ' 1 ' 1 ' 1 ' 1 ' 1 ' 1 ' 1 ' 1 ' 1 ' 1
789 10 II 12 1 2345678
A w TIME OF DAY PM
FIGURE 25 - DISSOLVED SULFIDES AT STATION 6.
-------
OJ
1970
v.
o
z
Z
UJ
O
K
tf
JUNE
20 23
500
40O
3OO
ZOO
IOO
0
150
IOO
50
JULY
5 10 15 20
AUG
X X
I
-* X
ft'
.X
BEFORE AERATION
AUG.
10 15 20 25
SEPT
10 15 2
o
x
9
o
OCT.
',° p f°
AFTER AERATION
NOV.
0-BOD5
X-COD
FIGURE 26- BOD5 AND COD AT STATION 6.
-------
and resulting extreme turbulence at Station 5A were com-
pletely el irninated. The flow in the 8 in. gravity sewer
during samp I ing was consistently at or just below a half
pipe indicating a relatively steady contribution of about
100 GPM. The flow through the U-tube averaged around
1400 GPM with an aspiration of 15 CFM for an air/water
volume ratio of 0.08- Oxygen transfer averaged 5-1 mg/l
from an average initial demand (IODJ of 2.5 mg/l to an
average residual D.O. of 2.6 mg/l. Table I is a tab-
ulation of 13 sets of measurements taken at 5B, a tap
immediately upstream of the Venturi, and in 5A the man-
hole receiving the combined discharges of the U-tube and
the untreated 8 in. gravity sewer. Flow through the U-tube
accounted for 96% of the combined discharges. The data
in Table I reflects the original entrance elbow config-
uration of the U-tube as shown in Figure 8 and consequent-
ly relates to sulfide, D.O., BOD5 and COD data at Sta-
tions 6, 13 and I .
Table 2 is a tabulation of data taken after final modifi-
cation of the entrance elbow as shown in Figure 9« There
is no indication that oxygen transfer in the U-tube was in-
creased by this modification, however, there was one sign-
ificant improvement. With the original configuration, a
period of 40 to 50 seconds elapsed between the initial flow
of sewage through the Venturi and the start of aspiration.
After modification, this lag was reduced to between 10
and 15 seconds. Since the average duration of flow during
an operating cycle was about eight minutes, the total
aeration per cycle was improved by roughly 7%- Data for
various air/water ratios and corresponding head losses are
also included in Table 2. Note that the upstream head
measured immediately upstream of the Venturi is negative
when aspiration is closed off or throttled. Under these
conditions the capacity of the I ift station is actually
increased by the installation of the U-tube. It is appa-
rent from this data that optimum oxygen transfer with natu-
ral aspiration occurs with flows above 1900 GPM, however,
a 3 to 4 ft increase in head loss results. Supercharging
to obtain higher air/water ratios resulted in drastically
increased head losses without a corresponding gain in
oxygen transfer. There appears to be about I 20 GPM or an
$% reduction in pump capacity from the installation of
the U-tube at this station for normal one pump operation.
For two pumps there appeared to be a loss in capacity on
the order of 300 GPM or I 2%» This reduction in capacity
54
-------
TABLE I IOD AT STATION 5B, UPSTREAM
OF THE VENTURI AND DO IN 5A
RECEIVING THE U-TUBE DISCHARGE
Sta. 5A
DO mg/l
2.4
3.6
2.8
2.8
4.1
2.9
I .9
1.9
'~l.6
2.0
2.8
2.2
2.6
2.6
Date
10/1/70
10/7/70
10/7/70
10/12/70
10/14/70
10/19/70
10/20/70
10/20/70
10/21/70
10/22/70
10/22/70
10/23/70
10/24/70
Average
Sta. 5B
IOD mg/F
1.3
1 .0
2.2
2.3
-0.5
2.0
3.9
3.9
2.0
4.3
3.1
3-9
2.6
2.5
m
Transfer
g/l 02
3.7
4.6
4.9
5.1
3.6
4.9
.8
.8
3.6
6.3
5.9
6.1
5.2
5.1
5
5
Air/Water Volume Ratio 0.07
55
-------
TABLE 2 TABULATIONS OF VARYING SEWAGE
AND ASPIRATION RATES AND THE
EFFECT ON TOTAL OXYGEN TRANSFER
HEAD LOSS IN THE U-TUBE AT STATION
Water
F 1 own ate
(GPM)
1570(1)
2060(2)
2000(2)
2180(2)
1580(1)
2180(2)
2090(2)
2090(2)
1340(1)
1400(1)
1960(2)
1920(2)
1280(2)
900(1)
1620(2)
1620(2)
A i r
F 1 owrate
(CFM)
0
0
5.5(3)
10.5(3)
7.5(3)
16.0(3)
17.0(3)
20.0(3)
14.0
15.0
28.0
28.0
20.0(4)
19.0(4)
40.0(4)
60.0(4)
• Air/Water
Vo 1 ume Rat i o
_ _
0.021
0.036
0.036
0.055
0.061
0.071
0.078
.. 0.080
0.107
0.109
0.120
0.158
0.185
0.277
Upstream
Head
(FT H20)
-4.75
-5.08
-3.75
-2.75
-5.25
-0.98
-0.92
-0.60
3.50
'3.83
7.50
7.08
20.83
17.25
28.60
29.17
Total
Oxygen
Transfer
(MG/L)
•
— — —
1 .1
2.4
3.3
3.5
4.7
. 4.7
4.5
4.9
6.4
6.5-
7.7
7.9
9.1
8.9
Lift Station 40
(I) One pump )
(2) Two pumps )
(3) Aspiration Air Throttled
(4) Supercharging with Compressor
56
-------
can be entirely el iminated by I i m i t i ng (throttl ing) the
aspiration air but with some reduction in oxygon transfer.
Data from Station 5 indicates that U-tube design can gen-
erally be adapted to existing pumps even when little or
no reserve pump capacity exists providing dissolved sui-
fides are below 2 mg/I. When a higher concentration of
dissolved sulfides make optimum oxygen transfer desirable,
it may be necessary to change the pump impel! ers or pos-
sibly pumps and motors to accomodate the higher head loss.
Table 3 is a tabulation of dissolved sulfides (Ss-j and
D.O. taken at Station 5 after act i vat i or1 and before mod-
ification of the entrance elbow lor the iJ-tube, It will
be noted that no D.O. was found in any sample from 5B, the
tap in the force main immediately upstream of the Venturi .
Immediate oxygen demand (IOD) was not run on these samples.
The residual D.O. measured in 5A, the manhole receiving the
U-tube discharge correlates very we!I with the data tabul-
ated in Table I when IOD was measured in the samp I"S from
5B. In contrasting the samples from 5B with those ol 5A
in both Tables I and 3, it must be real ized that the mea-
surements do not relate to the same slug of sewage, it
was not possible to make the two measurements «ithin the
approximately 30 second interval of travel between points
5B and 5A. The pairs of measurements in >B and )A were in
a I I cases taken during the same operating cycle and the
average values are considered significant. The data from
Table 3 confirms that the oxidation of su ! 1 ides is only
partially completed in the U-tube. The reduction in dis-
solved sulfides from Station 5B to 5A based on tin axerage
values of .15 mg/I and .06 my/I respecti\el> is on r he
order of 60% with a high average D.O, (2.3 mg/l) per-
sisting in Station 5A. This contrasts to a 90- reduction
at Station 6, only 370 ft downstream, and 93;'1 at Station
13, 1450 ft downstream, with no further aeration beyond
the air-water interface in the gravity sewer. While ob-
viously there is some oxygen enrichment ot the sewer atmo-
sphere as entrained air leaves the stream, this occurs in
the first few feet when residual D.O. in the stream is
highest and the cont i nu i ng ox i dat ion o I sulfides in t he-
gravity sewer appears largely, if not entirely, the result
of D.O. imparted to the stream in the U-tube.
Station 40 is one of dual wet we I Is of the pump station
pumping to the U-tube at Station 5. Station 40 receives
the 18 in. gravity sewer carrying the discharge from the
57
-------
TABLE 3
TABULATION OF DISSOLVED SULFIDES AND
DISSOLVED OXYGEN AT STATIONS 5B
(UPSTREAM OF THE' VENTURI) AND 5A (THE
MANHOLE RECEIVING THE U-TUBE DISCHARGE)
Date
08/18/70
08/31/70
08/31/70
08/31/70
08/31/70
09/08/70
09/09/70
09/18/70
09/28/70
09/30/70
10/07/70
10/14/70
10/19/70
10/20/70
10/20/70
10/21/70
10/22/70
10/22/70
Averages
Ti
me
1010
0845
0945
1045
1510
I 120
1000
1645
1435
1000
1025
1450
1055
1015
1500
I 150
1000
1445
5B-
mg/l S^
0.06
0.07
0.14
0.14
0.31
0.07
0.13
0.04
0.06
0.17
O.I 1
0.46
0.31
0.01
0.09
0.04
0.03
0.41
0.15
15 mg/l DO
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
5A
mg/l Sg:
0.05
0.04
0.08
0.06
0.21
0.05
0.15
0.01
0.04
0.06
0.07
0.01
0.00
0.00
0.02
0.01
0.01
0.20
0.06
J mg/l DO
2.8
1 .8
O.I
I .6
2.4
2.3
1 .3
3.6
3.6
2.8
2.7
4.1
2.9
I .9
1.9
1 .6
2.0
2.8 '
2.3
58
-------
ll-tube at Station 7 together with the flow of the 10 in.
gravity sewer entering the manhole designated Station 7A .
Station 40 is connected to Station 30 by a 24 in. equal izer
providing a combined wet we I I volume of 5,000 gal . Since
these two wet we I Is also receive the combined flow of two
10 in. and one 8 in. gravity sewers in addition to the in-
termittent discharge of the two aerated force mains, no
clear cut significance can apply to any sample. Despite
the questionable nature of samples from Station 40 (as dis-
cussed earl ier, the data obtained related to a sewage flow
containing between 40% and S5% aerated sewage). This is
the only data indicating the downstream effect of the ll-tube
at Station 7. Figure 27 is a daily plot of D.O. at Station
40 before and after activation of the aeration devices.
Before activation of the aeration devices D.O. ranged from
a low of 0.4 nig/I to a high of 3.5 mg/ I with an average
value of 1.9 mg/l. This high D.O. appears to be the re-
sult of high fa I Is from the 10 in. force main into Station
7A (4 ft), the 18 in. gravity into Station 40 (2 ft to
5 ft) and the 8 in. force main into Station 30 (3 ft to
6 ft). After activation of the aeration devices 0.0, in
Station 40 ranged from a low of 0.3 nig/I to a high of 3.8
mg/l with an average value of 2-3 mg/l. it is significant
in comparing data before and after aeration that the U-tube
at Station 7 el iminated the four foot fa I I into 7A with the
attendant oxygenation and stripping of a considerable
amount of HoS. The fa I Is into Stations 40 and 30, whi Ie
altered to ranges of 0 ft to 5 ft and I ft to 6 ft, res-
pectively, by raising the high water level to prolong the
pump cycle, sti I I existed with substantial iy the same tur-
bulence, oxygenat i on and stripping of sulfide as before.
Figure 28 is the daily plot of suI fides at Station 40, Be-
fore activation of the aeration devices dissolved suI fides
(^85) 'n Station 40 ranged from 0 to a high of 3.(H mg/l
with an average value of 0.42 mg/l• After activation of
the aeration devices dissolved suIfides (See) at Station
40 ranged from 0 to a high of 0.32 mg/l with an average
value of O.I I mg/l and an apparent reduction in dissolved
su I fides attributable to upstream aeration of 74/^. Fig-
ure 29 is the hourly plot of dissolved suI fides before
and after activation of the aeration devices. Figure 30
is the daily plot of BOD5 and COD at Station 40. Before
activation of the aeration devices, BODr ranged from a
low of 21 mg/l to a high of 320 mg/l with an average value
of 174 mg/l. COD ranged from a low of 64 mg/l to a high
59
-------
1970
ON
O
Ui
O
O
Ui
O
5
-i
3
UJ
O
tz
JULY
5 10 15 ^0 25
AUG
4
50 -
0 -
BEFORE AERATION
AUG.
10 15 20 25
SEPT.
10 15 20 23
OCT.
10 15 20 25
i I i T
NOV.
o
O
O
O
AFTER AERATION
FIGURE 27- DISSOLVED OXYGEN AT STATION 40.
-------
1970
V)
U
o
u.
Q
UJ
3
o
tO
CO
o
Q
z
UJ
o
tr
K
JUNE
20 2:
0
150
IOO
50
JULY
5 10 15 ZO 25
AUG
4
AUG.
10 15 20 25
SEPT
5 10 IS 20 25
OCT.
5 10 15 20 25
' i i i T
NOV.
BEFORE AERATION
AFTER AERATION
FIGURE 28- DISSOLVED SULFIDES AT STATION 40.
-------
a\
CO
111
o
ID
CO
o
UJ
o
CO
CO
0
_l
o
5.0
4.5
4.0
3.5
30
2.5
2.0
1.5
1.0
Oc
• O
0.0
: BEFORE AERATION (0)
L AFTER AERATION (X)
-
r o
-
.
•
_
:
-
'•_
•
.
-
'_
'. 0 0
° o
1 o o
o o . Q ox o
"oo°° ° o°°
|L ox° xxx xR)XoXxoo
i • i • i • i • i • i • i • i • i • i • i • i • i • i
789 10 II 12 1 2345678
A M TIME OF DAY PM
FIGURE 29- DISSOLVED SULFIDES AT STATION 40.
-------
OJ
1970
X
z
UJ
o
111
<9
>
X
o
UJ
o
£E
Ul
Q-
JUNE
20 23
500
40O
300
200
IOO
0
150
IOO
50
0
JULY
10 15 21
AUG
X X
X
xx o
o o
8n O ° °
° O ° o •
X •
BEFORE AERATION
AUG.
10 15 20 25
SEPT
5 10 15 20 25
ii'ii
OCT.
5 10 15 20 £5
I
I f T I
NOV.
X
d1
o o
x 9
<*>
AFTER AERATION
0-BOD5
X-COD
FIGURE 30- BOD5 AND COD AT STATION 40
-------
of 528 rng/l with an average value of 306 mg/l. After acti-
vation of the aeration devices BOD^ ranged from a low of
42 mg/l to a high of 351 mg/l with an average value of
152 mg/l. COD ranged from a low of 149 mg/l, a high of
393 mg/l with an average value of 251 mg/l. The apparent
reduction attributable to aeration is 13% for BOD^ and I 8%
for COD.
Station 7 is the location of the smalIer of two U-tubes
and is the upstream terminal of the demonstration. The
U-tube at Station 7 is installed on the discharge end of
2050 ft of 10 in. force main. The center! ine of the Ven-
turi is 30 in. above the center I ine of the original dis-
charge. Flow through the U-tube in normal automatic sin-
gle pump operation with an aspiration of 4 CFM was on the
order of 600 GPM. Upstream pressure immediately ahead of
the Venturi ranged between 23 and 37 in. H^?) with an aver-
age value of 25-2 in. HoO. With no aspiration, flow in-
creased to about 660 GPM. Upstream pressure was negative
ranging between -22 and -63 in. HoO with an average value
of -33.8 in. H^P) . The flow with the former free discharge
of the force main averaged 670 GPM. It appears that the
U-tube at Station 7 with normal pump operation and with an
aspiration of about 4 CFM increased the system head by
about 55 in. h^O which resulted in an \\% loss in capacity.
With two pump operation and normal aspiration at 8 CFM up-
stream pressure ranged between 80 and 100 in. h^O. Flow
was reduced from a free discharge capacity of 920 GPM to
795 GPM or about a \4% loss in capacity. Aspiration at
795 GPM was between 7 and 8 CFM which is equivalent to an
air-water ratio of .07. For normal single pump operation
viz: a flow of 600 GPM and an aspiration of 4 CFM the air-
water volume ratio was .05.
The entrance elbow was modified in the same manner as pre-
viously described for Station 5 U-tube, but did not appear
to improve transfer. However, the lag between sewage flow
and the start of aspiration was reduced. In the case of
Station 7, the reduction was from an average I 10 seconds
with the original configuration to between 30 and 40 sec-
onds with the new elbow. Figure 31 is the daily plot of
D.O. at Station 7A before and after activation of the
aeration devices. Before activation of the aeration de-
vices D.O. in Station 7A ranged from 0 to a high of 1.7 mg/l
with an average value of .62 mg/l. After activation of
64
-------
ON
1970
I!
3
O
Ul
3
o
UJ
o
a:
UJ
a.
JUNE
ZQ 2S
0
ISO
IOO
50
JULY
AUG
4
o
o o
-e-9-
BEFORE AERATION
AUG.
10 15 2O Z9
* I I
SEPT.
5 10 [5 20 25
1 ? i i i
8
OCT. NOV.
5 10 15 20 25 5
o
AFTER AERATION
o
000
FIGURE 3!-DISSOLVED OXYGEN AT STATION 7.
-------
the U-tube, D.O. ranged from a low of 0.2 mg/l with a high
of 3.8 mg/l with an average value of 2-1 mg/l, tt should
be noted here that before activation of the U-tube samples
had to be taken immediately after flow from the force main
stopped and are not fully representative of conditions
during the force main discharge. The same is true for
sulfide, BODr and COD samples. Figure 32 is the daily
plot of sulfides at Station 7A . Before activation of the
U-tube, dissolved sulfides (Sor) ranged from zero to a
high of .91 mg/l with an average value of .26 mg/l. After
activation of the ll-tube, dissolved sulfides (Sgcj) in 7A
ranged from zero to a high of .21 mg/l with an average
value of .06 mg/l. Figure 33 is the hourly plot of sul-
fides in Station 7A. Figure 34 is the daily plot of BODr
and COD at Station 7A before and after activation of the
U-tube. Before activation of the U-tube, BODr ranged
from a low of 88 mg/l to a high of 178 mg/l with an aver-
age value of 126 mg/l, COD ranged from a low of 158 mg/l
to a high of 385 mg/l with an average value of 237 mg/l .
After activation of the U-tube, BOD^ ranged from a Iow of
31 mg/l to a high of 160 mg/l with an average value of
96 mg/l. COD ranged from a low of 105 mg/l to a high of
268 mg/l with an average value of 186 mg/l. The apparent
reduction attributable to the U-tube was 77% for dissolved
sulfides, 22% for COD and 24% for BOD5. Table 4 is a
tabulation of IOD and D.O. taken at Stations 7B and 7A.
This data reflects the original configuration of the U-tube
and consequently relates to other downstream data taken
during the demonstration. No instream data was taken
after modification of the elbows of the two U-tubes since
aspiration rates were not increased. IOD ranges from a
low of I.0 mg/l to a high of 5-5 mg/l with an average
value of 3.1 mg/l. D.O. ranged from a low of 0.4 mg/l to
a high of 3-8 mg/l with an average value of 1.7 mg/l.
There is good correlation between the D.O. recorded in
Figure 31 for Station 7A after activation of U-tube as
originally configured and the 0.0. recorded in Table 4.
VENTURI AND ASHBROOK AERATORS
The pumping rate through the in-I ine Venturi ranged be-
tween 920 and 1080 GPM. During test hours and dry weather,
the pumping cycle ranged between four and six minutes,
and the interval between pumping from seventeen to twenty
66
-------
1970
CO
iZ
CO
o
bJ
o
CO
CO
5
_j
Z
4E
O
5
^
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JUNE
20 25
5
4
3
2
1
150
100
50
o
-
~
~
-
O
_
.
. \
V
r
s
I
i
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FIGURE 52
„,„ „ ,„ _._
JULY
5 10 15 20 25
f i •
o
Ol y"4
I
f\
fj \
i V i i
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hi
i
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I/V 1
AUG
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i ; ' I
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Vj
FORE AERATSON
|
AUG. SEPT OCT NOV.
10 15 20 25 5 10 15 20 25 5 10 15 20 25 5
— r- i 1 1 ! T T" T — 1 | ! I i T r "T^- r —
O O °O° O g^Q Q Q (jggQQ
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; J 1 ^^ ' « ! U * I
y ' \ / \ \ ^ •' v V"" 1^1 \
I/ '-; » V V / w V
V s v \ /
V
1| AFTER AERATION
- DISSOLVED SULFiDES AT STATION 7-
-------
Os
00
CO
Ul
o
-i
CO
o
Ul
o
CO
CO
a
i
5.0
4.5
4.0
3.5
3.0
2.5
2.0
15
I.O
0.5
0.0
: BEFORE AERATION (0)
•_ AFTER AERATION (X)
-
"
-
-
-
-
'
"'
-
- 0
L
: o
- xfltfxxxx°x * xxx x « x
1 ' I ' 1 ' 1 ' 1 ' 1 ' 1 ' I ' I ' 1 ' l ' I ' 1 ' 1
789 10 II 12 1 2345678
AM TIME OF DAY PM
FIGURE 33- DISSOLVED SULFIDES AT STATION 7.
-------
1970
<9
a
o
Ul
o
X
o
_J
5
ui
o
oc
UJ
Q.
JUNE
500
400
300
ZOO
IOO
0
150
IOO
50
JULY
5 10 15 20 25
AUG
o x
BEFORE AERATION
AUG.
10 15 20 25
SEPT
5 10 15 20 25
it'll
OCT.
5 10 15 20 £5
T T T T T
NOV.
-4-
X
X X
o
§
x
o
0-BOD5
X- COD
AFTER AERATION
FIGURE 34-BOD5 AND COD AT STATION 7
-------
TABLE 4
IOD AT STATION 7B, UPSTREAM
OF THE VENTURI AND D.O. IN 7A
RECEIVING THE U-TUBE DISCHARGE
Date
10/7/70
10/7/70
10/12/70
10/14/70
10/19/70
10/20/70
10/20/70
10/21/70
10/22/70
10/22/70
10/23/70
10/24/70
Average
Sta. 7B
IQD mg/l
1.3
2.2
1.8 '
I .0
2.9-
4.5
3.3
3.4
5.5
3.4
3.9
3.5
3.1
Sta. 7A
DO ing/I
2.0
2.4
3.8
3.3
1.6
0.6
.-2.4
0.7
0.4
1.7
0.2
1.6
1.7
Transfer
mg/l O2
3.3
4.6
5.6
4.3
4.5
"5.1
5.9
4.1
5.9
5.1
4.1
5.1
4.8
Air/Water Volume Ratio 0.04
-------
minutes, Prel iminary tests disclosed that the Ashbrook
device would not aspirate a measureable volume of air.
Pressure drop across the Ashbrook was 10 psi and upstream
pressure was 12-5 psi with a flow of 910 GPM. Because of
the failure of the Ashbrook to aspirate and the impractic-
abi I i ty of suppIy i ng air in bottIes only the i n-I i ne
Venturi was activated during this demonstration.
Samp I ing taps were located immediately upstream and down-
stream of both the in-I ine Venturi and the Ashbrook device.
The location of the downstream tap proved to be too close
to the Venturi outlet to provide for absorption of oxygen
or the oxidation of suI fides. Transfer of oxygen across
the in-I ine Venturi based on eight samples at the taps
was consistently less than I my/I, however, when a 50 ft
length of garden hose was imposed between the downstream
tap and the samp I ing bottle, transfer in five samples
averaged above 2 rng/I . Obviously no correlation exists
between a 50 ft length of 3/4 in. garden host and several
hundred feet of 8 in. force main and this data is mean-
ingless to this demonstration. On the other hand it serves
to prove that the reaction was incomplete at the tap pro-
vided downstream of the Venturi and designated Station 32,
COD and suIf ides run on these samples from Station 32 were
in many instances higher arid never significantly lower
than corresponding measurements run on samples i rom Sta-
tion 31 immediately upstream of the Venturi despite an
aspiration of 5 to 6 CFM equivalent to an air-water volume
ratio of .04. Station 30 receives the discharge from the
in-line Venturi at Stations 31-32- The three to seven
foot drop from this force main to the wet we I I water sur-
face was not el iminated. 19 D.O. measurements before
activation of the Venturi ranged from a low of 0.7 nig/I to
a high of 3-0 mg/l and averaged 2-03 mg/l. 13 D.O. measure-
ments taken after activation of the Venturi ranged from a
low of I.0 mg/l to a high of 3-8 mg/l and averaged 2.33 mg/
This would appear to credit the in-I ine Venturi with a
gain of 0.3 nig/I or no significant improvement over the
aeration real ized from the fa I I and splash of a high force
main discharge. In any event the persisting stripping of
hydrogen sulfide brought violent complaints from residents
in the vicinity and forced curtailment of samp I ing from
Station 30.
71
-------
SECTION VI
SUMMARY OF RESULTS
Tables 5 and 6 ore tabulations of mean values of a I I mea-
surements of DO, dissolved sulfides (Sor), BOD^ and COD
before and after aeration, and the percent reduction in
dissolved sulfides, BODc and COD attributable to aeration.
These values are derived from measurements in the mixed
stream and are not weighted to reflect the percentage of
unaerated flow in each sample. Table 5, however, includes
a tabulation of the approximate percentage of the flow
that issues From the aeration device immediately upstream
of the samp I ing station at the time of samp I ing. The
remainder of the flow into samp I ing stations at the time
of samp I ing is from untreated gravity sewers previously
shown in Figure 2- With the exception of Station 40,
these percentages are based on measured depth of flow in
gravity sewers and metered flow through the Venturis at
the time of sampling. As wi I I be discussed later in this re-
port, it proved impossible to accurately determine a ratio
oF aerated to untreated sewage in either Station 30 or
40. The tabulations in Tables 5 and 6 I ist the stations
in order of progression from the upstream terminal (Sta-
tion 7) to the downstream terminal (Station I) and pre-
sent a concise summary of the results of this demon-
strat ion.
It will be noted that a significant D.O. is recorded be-
fore activation of the aeration devices at Stations 7, 40,
6 and 13. This is attributable to the Fa I I with resultant
splash and turbulence from the high force main discharges
at Stations 7, 30 and 5 and a high gravity drop into Sta-
tion 40. With the installation of the U-tubes, the falls
of seven and four feet, respectively, from the invert of
the force mains to the invert of receiving sewer were
el irninated from Stations 5 and 7, but the three to seven
foot drops from the invert of the force main and gravity
sewer to the water surface in the receiving wet we I Is at
Stations 30-40 remained. As would be expected, the
stripping of h^S at Stations 7, 30-40, and 5 was extreme
prior to activation of the aeration devices with pro-
nounced odor and clear evidence of corrosive attack. Par-
ticularly vehement complaints from residents in the
72
-------
TABLE 5 TABULATION OF AVERAGE VALUES OF ALL MEASUREMENTS OF DO AND DISSOLVED
SULFIDES (Sg5) BEFORE AND AFTER ACTIVATION OF AERATION DEVICES
Stat ion
7B(l)
7A(2)
40(3)
5B(I)
5A(2)
6
13
2(0
1
% Flow (4)
Aerated at
Samp 1 i ng Po i nt
0
80
40-85
40-95
96
95
79
39
93%
D.O. mg/
Before
Aerat i on
0.6
1 .9
_ . _ .
...
0.8
0.0
0
1 (5)
After
Aerat i on
0
2.1
2.3
0
2.5
1 .6
0.7
_ — _
. 1 .4
SRC; mg/
Before
Aerat i on
0.26
0.42
. . . .
...
.0.51
0.30
_ _ _
0.63
1 (5)
After
Aerat i on
0.27
0.06
O.I 1
0.15
0.06
0.05
0.02
. — .
0 '
S85 (5)
W *J
Reduct i on
in
•74%
«...
90%
93%
100$
(l) Stations nonexistent before aeration. 5B and 7B are taps upstream of the
Venturi aspirators. Station 2 is the airl ift aerator.
(2) 4 ft and 7 ft-fall into stations 7A & 5A, respectiveIy, from force main prior
to aeration only. El iminated by U-tube.
(3) 3 ft to 6 ft fa I I into station from gravity sewer before, and after aeration.
(4) This column, except for Station 40, is based on measured flow at the sampling
station and is the percentage of total flow (or volume) in the sampling sta-
tion at the time of sampling issuing from the aerator immediately upstream.
The conditions controlling at Station 40 are explained in the text.
(5) These values are as measured in the mixed stream and are not weighted to
reflect the percentage of aerated flow in the samples.
-------
TABLE 6
Stat i on
7B
40
5B
5A
6
13
I
TABULATION OF AVERAGE VALUES OF ALL
MEASUREMENTS OF COO AND BOD5 BEFORE
AND AFTER ACTIVATION OF THE AERATION
DEVICES
COD
Before
Aerat i on
306
296
315
310
After
Aerat i on
220
186
251
352
319
260
, 250
' 208
Reduct i on
22%
2\%
33^
BOD5
Before
Aerat i on
126 '
174
151
176
169
After
Aerat i on
103
96
1 52
221
194
125
150
128
Reduct i on
24% .
! 3%
\1%
\ 5%
24%
-------
vicinity of Stations 30-40 had forced the Parish to seal
the covers of these wet wells and run a 6 in. vent under
a railroad embankment out into an open field. Opening
these sealed covers at Station 30-40 to take samples and
measurements brought immediate and violent opposition which
persisted despite assurances that the work would be of
short duration and was specifically aimed at reducing and
possibly el iminating the odor.
Unfortunately after aeration, even with dissolved sulfides
reduced 74% to a mean value of O.I mg/l, some odor persist-
ed and sampling had to be curtailed at Stat i on 30-40, Th i s
appears to confirm observations by Pomeroy and Bowlus (6)
to the effect that, while concentrations at or below O.I
mg/ I dissoIved suIfides may be acceptable in a smoothly flow-
ing gravity sewer with a nominal pH (about 7), concentra-
tions significantly below O.I mg/l dissolved sulfides can
produce totally unacceptable levels of h^S in the sewer
atmosphere if there is turbulence, particularly if the pH
is at or be Iow 7•
Contrary to the situation persisting at Stations 30-40,
the U-tubes at Stations 5 and 7 are set with the invert of
their discharge practically level with (O.I ft above) the
invert of the receiving sewer. The aerated stream from
the U-tube blends very smoothly with the untreated stream
and there was no detectable odor of HoS in either manhole
even though dissolved sulfides as high as 0.2l mg/l on one
occasion were recorded in the combined (aerated and un-
treated) stream. Table 5 gives good indication of the
continuing oxidation of the dissolved sulfides in the
gravity sewer downstream of the aeration device. At Sta-
tion 7A, the discharge manhole directly receiving the
aerated discharge of that U-tube, the mean D.O. was 2.1
mg/l and the reduction in dissolved sulfides was 74%'
This amounted to a decrease from a mean of 0.26 mg/l before
aeration to a mean of 0.06m9/l after aeration. At Sta-
tion 6, 370 ft downstream of the discharge of the second
U-tube (Station 5A), the mean D.O. decreased to I.6 mg/l
(from 2.5 at 5A) and the reduction in dissolved sulfides
was 9®%• This amounted to a decrease from a mean of 0.51
mg/l before aeration to a mean of 0.05 mg/l after aeration.
At Station 13, 1450 ft downstream of 5A, the mean D.O.
dropped to 0.7 mg/l and the reduction in dissolved sul-
fides was 93%- This amounted to a decrease from a mean
75
-------
0.30 mg/l before aeration to 0.02 nig/I after aeration by the
U-tube.
Contrasting the sulfide concentrations in the system be-
fore and after aeration, aside from the significant overalI
reduction, it will be noted that before aeration, except
for Station 13, there was a typical consistent build-up
as the flow progressed downstream. After aerat: m, except
for Station 40, there was a consistent drop as the fIow
progressed downstream. The dip in sui fide concentration
at Stat ion 13 before activation oi the aeration devices
appears to reflect the transfer of oxygen to and the strip-
ping of h^S from the sewage by the seven foot fa!I from
the force main into Station 5A and the continuing oxidation
of suI I ides in the sewer between Stat ions 6 and I3» This
is supported by the measured D.O. before instal I at ion of
the IJ-tube of 0.8 rng/l and O.Oi mg/ ! at Stations 6 and 13,
respect i veIy, before act i vat i on o1 t he a e r a t ion devices.
As shown by Table 5, the percentage of aerated sewage in
any sample at the time of samp I ing is, except for Station
40, based on the measured flow in the sampi ing station at
the time of samp I ing. In the cases of both Stations 30
and 40, which are two 9 Ft 0 in. diameter bottom connected
wet we! is with a combined volume on the order of 5000 gals,
that receive the continuous flow of two 10 in. and one 8
in. gravity sewers plus intermittent flows from an S in.
and 10 in. Force main, the percentage of aerated sewage
in any sample could range from 40/& or less, to 85V:>. It
can be assumed that percentage approaches the higher value
because of the fact that samples were consistant!y taken
only at high water level and in the case of Station 40,
dur i ng or i mmed i ate Iy foI Iow i ng i nfIow from Stat ion 7.
However, the significance oF data from Station 40 is some-
what questionable. In all other stations the rate of flow
of contributing gravity sewers, the Flow through the
Vent.uri aspirators and the flow in the sewer receiving the
combined flows could be readi ly determined.
Table 6 tabulates the mean values of a!I BODr and COD
measurements taken before and after activation of the
aeration devices. There appears to be a significant re-
duction attributable to each aeration device and a sign-
ificant cumulative reduction after aeration at all sta-
tions. There does not appear to be a really clear cor-
relation between suI fides and either BOD^ or COD, With
76
-------
the degree of treatment involved in this demonstration, no
substantial reduction in BODr or COD could be anticipated.
The low average BODr and COD measurements tabulated in
Table 6 show quite clearly the heavy residual dilution
from persistently heavy rainfall encountered both before
and after activation of the aeration devices. This was
previously illustrated in Figure 14. Figure 14 would
appear to indicate a substantially heavier dilution in
the period before activation of the aeration device, how-
ever, instream measurements and sampl ing during both per-
iods were I imited to times when the flow was at or near
normal and consequently the residual effects of dilution
were probably more nearly equal. It can be presumed that
dilution did not seriously penal ize and certainly did not
unduly favor the performance of the aeration devices.
The spacing of Station 2 in relation to Station 5 was
based on an empirical method developed by C.L. Swanson (7).
The method is evaluated by appI ication of data taken at
Stations 5A and 13.
Swanson (7) hypothesized that oxygen demand in a sewer
originates from:
I. Oxidation of suIfides produced in the si ime
layer, Pomeroy and Bowlus (6).
2. Oxidation of suIfides produced in the flowing
stream, Pomeroy (8).
3. Oxidation of sulfides and other materials pro-
duced in deposited sol ids in the sewer.
4. BOD demand of sewage (10).
5. TrickI ing fiIter effect in which the sewer sur-
face is analogous to the rock surfaces of a
trickl ing fiIter under submerged flow conditions.
Since no BOD reduction was observed between Stations 6 and
13 (see Table 6) it was assumed that the trickling filter
effect was nil and accordingly this factor was eliminated.
Since deposited sol ids were minimal in the test reach of
sewer this factor was el iminated.
77
-------
It was assumed that sufficient oxygen would be available
in the sewer atmosphere to meet the demand and that trans-
fer would be dependent on the width of the air-water inter-
face and directly proportional to the D.O. deficit (D.O.
at saturation minus the D.O. of the sewage stream) arid
the Reynolds Number as demonstrated by Davy (9). No attempt
was made to correct oxygen transfer for temperature or
oxygen concentration in the sewer atmosphere.
The input tor calculation of required spacing by Swanson's
method (7 J is:
BOD at Station 5A (Table 6) 194 mg/l
D.O. at Station 5A (Table 5) 2-5 mg/l
Average i nstream temperature 29° C
D.O. at Station 13 (Table 5) 0.7 mg/l
Deoxygen!zation constant (KyQj 0.15
Sewer Diameter 21 in.
Average Depth of Flow II in.
Average veIoc i ty 2.12 FPS
On the basis of data from Stations 5A and 13 the calculated
spacing by Swanson's method (?) would be about 2200 ft.
The actual distance is 1500 ft. This apparent discrepancy
must be viewed in the I ight of the fact that roughly .15 MGD
of the I.4 MGD flow into Station 13 is from four untreated
laterals entering the system between Stations 6 and 13-
As a consequence I\% of the flow into Station 13 is not
reflected in the data from Station 5A and the calculated
spacing should exceed the actual distance by an appreciable
amount. No data was taken from the four laterals and con-
sequently it, cannot be determined if or to what extent the
bu i I d up in BODr- between Stations 6 and 13 (See Table 6)
is attributable to the four untreated laterals. On the
other hand, since the average D.O. before aeration was
0.8 mg/l at Station 6 and zero at Station 13, (see Table
5) it can be assumed that the D.O. of the four laterals
approached zero or possibly carried an oxygen demand. If
it is assumed that the !\% contribution of the four later-
als was at zero D.O. and the D.O. at Station 5A adjusted
by simple proportion to 2-2 D.O. (.89 x 2-5 = 2.2) then
the calculated spacing by Swanson's method (7) would be-
come 1491 ft or very nearly the actual spacing (1500 ft)
between Stations 5A and 13-
78
-------
SECTION VII
REFERENCES
i. Laugh I in, James E., "Studies in Force Main Aeration",
Journal of the Sanitary Engineering Division, Pro-
ceedings of the American Society of CiviI Engineers,
4I50-SA6, PP 13-24 (Dec 1964).
2. Bruijn, Jacob and Tuinzaad, Hendrick, "The Relation
ship between Depth of U-Tubes and the Aeration
Process", Journal of the American Water Works
Association, 50, PP 879-883 (July 1958).
3. Mitchell, Rex C, "U-Tube Aeration"1, Rocketdyne
Division of North American Rockwell Corporation,
EPA Project; 17050 DVT, Contract 68-01-0120.
4. Standard Methods for the Examination of Water and
Waste Water, Twelfth Edition (1965).
5. Baumgartner, Wm. H., "Effect of Temperature and Seep-
ing on Hydrogen SuIfide Formation in Sewage", Sewage
Works Journal, 6-3, PP 399-412 (May 1934).
6. Porneroy, Richard and Bow I us, Fred D „ , "Progress Re-
port on Sulfide Control Research", Sewage Works
Journal , i*-4, pp 597-640 (July 194^
7. Swanson, C.L., EPA Project Officer, "Literature
Review and Development of Empirical Methods for
the Spacing of Sewer System Oxygenation Fac iI ities"
(Dec 9, 1968).
8. Porneroy, Richard, "Generation and Control of Su I f i des
in Filled Pipes", Sewage and Industrial Wastes, VoI 31,
No. 9, PP 1082-1095 (September 1959).
9. Davy, W.J., "Influence of Velocity on Sulfide Gener-
ation in Sewers", Sewage and Industrial Wastes, Vol 22,
No. 9, PP I 132-1 137 (September 1950).
0. Babbitt, H.E., Sewage and Sewage Treatment, John
Wiley and Sons Publishers, 7th Edition, pp 317-319
(1967).
79
-------
SECTION VIII
APPENDICES
Page No
A. Computer Program for Total Dissolved
Sulfide Calculations ........
B. Tabulation of Field Data ......... 85
80
-------
APPENDIX A
COMPUTER PROGRAM FOR TOTAL DISSOLVED SULFIDE CALCULATIONS
To attempt hand calculation of total dissolved suI fides
from electrochemical measurements in a project of this size
would be impractical. Accordingly, a rel iabIe computer
program is essential to this method of measurement.
The program language is IBM 1130/1800 Basic Fortran IV.
The computer employed was an IBM I 130 8K with disc, a
1442 card reader-punch and an I I 32 printer.
AM field data was ultimately punched on cards, however,
only three variables (chlorides, pH and absolute MvS ) are
used in the program to compute the total dissolved sulfides
The program derives from procedures out I ined in the Orion
Reference Manual for the 94-16 sulfide electrode employed
in this demonstration. A reference curve corresponding to
Figure 5 of the Orion 94-16 Manual was determined generat-
ing SULIA (sulfide ion activity As""). The Factor f for
converting sulfide ion activity to total dissolved sulfides
is computed from precise pH measurement and approximate
ionic strength on the basis of Table 3 in the Orion 94-16
Manual. The computed value of dissolved sulfide concen-
tration is then punched on the data card to which may be
added any additional pertinent field data for subsequent
I i st i ng and corre I at i on.
-------
• IOCS ICARD. 11 J2PR INTER .DISK!
•LIST ALL
•ONE WORD INTEGERS
•NAME TSULF
•ARITHMETIC TRACE
•TRANSFER TRACE
REAL MV
INTEGER STA.DATEdliTINE
DIMENSION ARGI10I. VALI10)
WRITEIJ.10I
10 FORMAT! U.' SULPHIDE
1 PPM IONIC CONCTN SULPHIDE PPM './.1X.'
2STATION DATE TIME MV ACTIVITY PH CHLORIDES
3 STRENGTH FACTOR CONCTNIM) SULPHIDE 'I
20 READI2.JO) I DATE I II . 1-1.2 I .STA.T IMt.PH.MV
30 FORMAT(2I2iA2.I».13X«F5.2«F5.0)
DATE(3>»70
CLPPM-200.
Xl-71*.
X2-845.
T1-ALOOI0.001I
Y2-ALOOI0.100I
SLOPE-IT2-Y1I/I«2-»1I
B'Tl-SLOPE'Xl
rY-SLOPE»MV«8
OO
ARSID-1
AR6I2I-2
ARG(3I.»
AROI4I-4
ARGI5I.7
ARGIt)>t
ARGI7)-10>
ARGHI-12.
ARG{9)»13«
ARGdOI-l*.
DO 100 L-l.»
GO TO (52.5».5«i5»I.L
92 VALI1)>I.*E1*
VALI2I-».»SU
VAL(3l-».»eU
VAL(»l-».7t7
VAL(»I"1.7E»
VALI6)»I>9E*
VALITI-I.OE2
VALHI-10.J
VALHI-1.7*
VALI10I.1.
GO TO to
?« VALI1)>(.*E1*
VALI2I-«.»E1S
VAL(II»t>»Etl
VAL (»)"». 7E7
VAl.UI-l.7E6
VAL(»I.».2E»
VALI7I.6.3E2
V'ALHI.10.9
VAUI9I-3.7*
VALI10I.1.
GO TO »0
56 VAi.ll). I. »E19
VAI.l2Ut.m3
-------
VALI3)-».9E11
VAL «•!•».»E7
VALI9l-l.»E6
VALI4I-9.7E4
VAL<7>.«.«£2
VALlll-10.3
VALitl-».T4
VALI10I-1.
00 TO »0
91 VM.lll-t.Mlf
VALC2I-«.»E1»
VALI3l'i.9Ell
VU.I4UV.1E7
VALI9I-1.9E6
VAL(6I-1.1£9
VALI7I-1.0E3
VALKI-11.2
VALI9I-3.74
VALI10I-1.
60 DO 70 1*1(10
VAL(II*AL06(VAt60
$0 CONTINUE
90 FFACT-VALI1-1I»IPH-AROII-U!•(VAL(11-VAL(1-1)I/(AKOtIl-AHOl1-11)
GO TO IV2t«4»«6t9tl(L
92 A-EXPIFFACT)
OO GO TO 100
r-j 9* B-EXPIFFACTI
SO TO 100
96 C-EXPIFFACTI
GO TO 100
91 0-EXPIFFACTI
100 CONTINUE
A*GUI»10.E-»
ARSI2I-10.E-9
ARGHI-10.E-2
ARGI4I-10.E-1
VALlll'A
VALI21-B
VALI3I-C
VAL 141 *D
DO 200 1-1.4
IFIXION-ARG(I»220i200<200
200 CONTINUE
220 FFACT-VALU-l>»(XION-ARGT[ME«KVtSULIA«PM«CLPPM.XION»FFACT
l.SCTM.SCTPM
900 FORMATI9X>A2>4X.3I2iI10>F8.0i2X.Ela.3.F7.2>3X>4E10<3iF10-4)
WRITEI2I450) SCTPM
»50 FORMATI64X004A
STA .0090 DATE >0093 TIME «0094 I .0039 L «0096
-------
STATEMENT ALLOCATIONS
oo
10 .0082 30 -012* 900 -012E *90
70 -0313 80 -032B 90 -0333 92
FEATURES SUPPORTED
TRANSFER TRACE
ARITHMETIC TRACE
ONE -ORO INTEGERS
IOCS
CALLED SUBPROGRAMS
FALOG FEXP FAOO FADOX FSUB
SIARX SFIF SSOTO SREO SHRT
»EAL CONSTANTS
.20000CL 03-0062 .7860COE 03-006*
•100000E 01-006E
•lOQOOGg 02-007A
•890000E U-0086
.37*0<10E 01-0092
•880000E 03-009E
•20000GE 01-0070
•120000E 02-007C
•970000E 08-0088
.920000E 05-009*
. 190000E 07-OOAD
• 01>D 20 -0199 52 -0203 5* ,'12*1 it -027F it .0260 60 -02F9
-0362 9* -0369 96 -0370 »8 -0377 100 -037C 200 -03C« 220 -03CC
FSOBX FMPT FDIV FLO FLD« FSTO FSBR FOVR SFAR SFA«»
SCOMP SFIO SlOIX SI Of SIOI SUBSC CARD! PRNTZ SDFIO
•8*5000E 03-0066 • 100000E~02-C06i *100000E 00-006A *394S7oE 05-006C
«*OOOOOE 01-0072
.13QOOOE ^2-007E
.17000DE 07-008A
»830000E o3»0096
.liOOOOE 06-OOA2
•60COOOE 01-007*
•J^OOOOE 02-0080
•89QOOOE OS-008C
•980000E 08-0096
.100000E C*-OOA*
•7QOOOQE 01-OU76
•890000E 20-0082
•aoooocE 03-ocee
•180000E U7-U09A
•132000E 02-OOA6
•900000E 01»007«
•890000E 16-OOt*
•103000E 02-0090
.970000E Oi-009C
.100000E-01-OOA8
•323640E 05-OOAA
INTEGER CONSTANTS
3-90AC 2-OOAO l-OOAE- 70-OOAF
CORE REQUIREMENTS FOR TSULF
COMMON 0 VAIUABL.CS It PROGRAM 978
END OF COMPILATION
-------
APPENDIX B
F IELD DATA
Data on pages 86 through 88, inclusive, is before activa-
tion o f the aeration d e v ices.
Data on pages 89 through 92 represents conditions after
activation of the aeration devices.
DEFINITION OF COLUMN HEADINGS
Date - The month, day and year of the in-stream measurement
and samp I e .
Station - The Station No. (See Figure 2).
Time - The hour and minutes based on the 24 hour clock.
Depth (inches - The depth of Flow in the gravity sewer.
Temp (°F) - Ihe i nstream temperature of the sewage.
pH - The pH measured i nstream.
Su I f i de Activity (MV) - The sulfide activity in absolute
millivolts measured i nstream .
D.O. - The D.O, run on a 300 m! sample taken simultaneous
with in stream measurement of pH and MV S~ .
BODr - The five day BOD run on a 300 ml sample taken sim-
taneous with i nstream measurement of pH and MV S .
COD - COD run on the same sample as BODr.
EBOD - BOD5 adjusted from the incubation temperature (20°C)
to the actual i nstream temperature.
Standard Su I f i des (Sg^) - mg/l total dissolved su! fides
adjusted to a standard temper-
ature of 85° F.
Effective su I f i des - mg/I total dissolved sulfides in stream
at stream temperature.
85
-------
oo
DATS
70270
70270
70870
70870
70870
70870
70870
70970
70970
70970
70970
70970
70970
71670
71670
71670
71670
71670
71670
71770
71770
71770
72070
72070
72070
72470
72470
72470
72470
62370
62670
63070
63070
70270
70270
70670
70670
70670
70670
71370
72070
72470
72470
72770
72770
73070
73070
73070
73070
73070
73070
73070
73070
80470
80470
80670
80770
80770
STA-
TION
1
1
1
1
1
1
1
1
1
J
1
1
1
1
1
1
1
i
1
1
1
1
1
1
1
1
1
1
1
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
TIME
HOURS
1621
1200
721
821
930
1030
1200
1219
1319
1449
1549
1730
1803
915
1030
1120
1300
1400
1500
930
1220
1430
913
1013
1200
900
1000
1134
1333
1920
1600
910
1439
1054
1534
854
1030
1200
1424
1394
1430
1039
1424
804
1004
624
824
939
1054
1424
1534
1634
1724
1324
1524
724
710
1020
DEPTH
INCHES
13.30
11.29
14.00
14.00
14. Ou
14.00
14.00
14.00
12.90
12.00
11. SO
11.00
12.00
13.90
It. 79
11.00
14.29
13.29
11.29
22.90
,
12.00
24.00
29.00
41.00
13.29
16.00
22.90
23.79
.
(.00
7.00
6.73
9.29
11.50
9.29
12.00
9.00
7.00
5.50
10.29
10.79
11.00
11.00
10.29
9.75
8.30
9.00
9.29
10.79
1.00
7.50
8.00
e.oo
10.00
8.29
8.79
10.90
TEMP
FAR.
16.0
19.9
89.0
• 6.0
19.0
83.3
86.0
88.0
88.0
89.0
88.0
«6.0
19.3
83.0
88.0
87.0
87.0
87.0
87.0
86.0
88.0
87.0
83.0
86.0
• 6.0
82.0
82.0
83.0
86.0
84.0
84.0
83.3
84.3
84.0
87.0
83.0
84.3
83.0
88.0
87.0
83.0
83.0
84.0
82.0
83.0
80.0
83.0
83.0
83. a
87.0
88. 0
86.0
86.0
86.0
86.0
83.0
82.0
87.0
PH
6.90
7.01
7.10
7.33
7.42
7.36
7.13
7.01
6.90
7.01
7.20
7.00
6.96
7.18
7.17
7.23
7.20
7.13
7.06
8.19
7.19
7.11
7.17
7.32
7.20
7.56
7.59
7.85
7.60
6.94
7.05
7.44
7.12
7.0C
7.00
8.00
7.21
7.30
7.28
7.21
7.02
7.60
7.54
7.32
7.44
7.21
7.30
7.32
7.32
7.23
7.23
7.29
7-17
7.30
7.74
7.iO
7.27
6.96
5ULFIDE
ACTIVITY
M.V.
530.
340.
519.
933.
580.
571.
979.
598.
555.
540.
539.
920.
509.
559.
970.
570.
560.
940.
955.
590.
560.
563.
530.
556.
550.
562.
576.
575.
575.
520.
550.
551.
585.
365.
547.
580.
562.
571.
558.
554.
508.
570.
558.
510.
545.
475.
535.
545.
553.
540.
545.
542.
950.
573.
565.
470.
450.
350.
0.0.
MG/L
0.0
0.0
0.0
0.0
0.0
0.0
.
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
.
.
.
0.0
0.0
c.o
0.0
0.0
0.0
0.0
1.2
1.3
0.2
0.8
r.o
0.0
0.0
0.0
0.2
1.3
2.1
1.9
0.0
0.5
l.S
0.6
1.1
0.6
1.4
0.0
1.3
0.4
1.0
0*8
0.7
1.0
1.4
1.1
0.0
8005
MG/L
137
48
101
134
132
191
210
199
189
228
157
33*
240
138
190
151
167
179
173
176
268
168
89
90
300
81
85
149
182
160
122
ioe
105
231
285
205
218
230
207
194
285
166
137
108
93
103
76
79
96
136
148
162
33
51
204
COO
MG/C
333
418
380
256
406
267
419
373
195
372
272
298
364
296
311
407
326
158
192
354
174
180
280
216
30}
298
218
256
383
486
354
381
332
336
539
391
335
355
89
196
117
160
190
169
275
111
149
4;i
416
85
75
901
E60D
MG/L
268
92
190
262
249
367
ill
420
398
499
331
654
461
260
401
307
380
364
331
344
565
341
156
176
587
137
143
281
336
291
222
193
194
420
579
359
403
434
436
394
537
294
249
169
163
194
138
167
188
266
290
317
58
86
414
STANDARD
SULFIDCS
MG/L
0.16
0.24
O.C4
0.06
1.63
0.96
3.45
0.88
1.08
0.21
0.11
0.05
0.03
0.65
1.41
1.16
0.61
0.16
0.63
0.41
0.61
1.01
0.08
0.33
0.29
0.30
0.82
0.32
0.64
0.07
0.49
0.17
6.00
1.83
0.40
0.33
0.77
0>65
0.40
0.37
0.02
U.48
0.22
0.01
0.11
0.00
0.08
0.16
0.32
0.12
0.16
0.12
0.32
1.31
0.19
0.00
0.00
0.59
EFFECTIVE
SULFIDES
MG/L
0.17
0.24
0.04
0.06
1.65
0.98
3.58
0.99
1.21
0.24
0.13
0*05
0*03
0.65
1.58
1.29
0.66
0.17
0.68
0.42
0.68
1.09
0.07
0.34
0.30
0.27
0.74
0.32
0.66
0.07
0.47
0.16
5.89
1.76
0.43
0.30
0.75
0.65
0.49
0.40
0.02
0.45
0.21
0.01
0.10
0.00
0.07
0.14
0.32
0.13
0.18
0.12
0*33
1.36
0.20
0.00
0.00
0.64
-------
oo
807-0
• OT70
60T70
63070
70270
70670
70970
71J70
71670
63070
70270
70270
70670
70670
70670
70670
71770
72*70
72*70
72770
73070
73070
73070
73070
73070
73070
73070
60470
10*70
• 0770
• 0770
80770
80770
62370
62670
62670
63070
63070
63070
70270
70270
70670
71370
71370
71370
71770
72070
80670
80770
80770
80770
80770
80770
62370
62670
63070
43070
70270
70670
70670
70670
70670
70870
6
6
6
7
7
7
7
7
7
13
13
13
13
13
13
13
13
13
13
13
13
13
13
13
13
13
13
13
13
13
13
13
13
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
*0
*0
*0
40
*0
40
40
»0
*0
40
1300
152*
1800
1110
930
1045
1515
9*5
930
14*9
1130
15*7
930
1100
1210
1434
1145
1051
1*36
1016
836
951
1108
1436
1546
1646
1736
1336
1536
1045
1312
1536
1812
1341
911
1527
830
1055
1356
1011
1441
1115
900
1030
1315
1100
1345
626
626
826
1220
1445
1715
1450
1545
845
1*15
1030
830
1000
1135
1400
600
14.00
9.75
9.50
•
•
•
•
•
•
s.oo
6.25
13.00
7.00
.
10.50
8-50
9.00
10.25
10.00
10.00
10.90
10.25
10.50
9.29
9.75
10.00
10.25
9.75
8.90
10.50
27.90
10.00
10.25
•
•
(
.
,
.
,
.
.
.
.
t
.
,
,
«
.
(
,
•
,
,
,
.
,
,
.
,
,
.
87.0
66.0
•*.o
8*.0
85.0
85.0
89.0
83.5
85.0
66.0
85.0
65.0
94.0
84.5
65.5
87.0
67.0
82.0
8*<0
85.0
64.0
84.0
86.0
67.0
88.0
86.0
85.0
66.0
65.0
87.0
87.0
67.0
82.0
86.0
84.0
83.5
84.5
• 5.0
86.5
85.0
87.0
83.5
83.5
6*. 5
86.0
86.0
85.0
82.0
62.0
63.0
87.0
66.0
65.0
83.0
82.5
82.5
85.0
85.0
83.0
83.5
84.0
67.0
84.0
7.00
7.62
7.27
7.32
7.3*
7.21
7.25
7.17
7.27
7.09
7.05
(..»»
7.98
7.30
7.62
7.30
7.11
7.57
7.46
7.»9
7.31
7.37
7.38
7.22
7.36
7.31
7.16
7.13
7.75
6.98
6.96
7.51
7.22
6.9*
7.12
7.10
7.32
7.05
7.26
7.05
7.00
• •30
7.50
6.00
7.27
7.79
6.98
6.96
6.98
7.0*
6.89
6.81
7.52
7.;2
7.00
7.21
7.18
7.08
8.*0
7.50
7.60
7.*8
7.02
550.
950.
539.
555.
570.
5*0.
500.
.70.
5*5.
569.
550.
530.
579.
5*0.
550.
565.
562.
565.
550.
506*
5*0.
593.
5oO.
535.
550.
550.
545.
558.
550.
530.
535.
519.
535.
530.
547.
540.
550.
581.
562.
565.
540.
563.
500.
9*3.
570.
532.
526.
510.
490.
530.
550.
530.
550.
550.
545.
565.
582.
558.
595.
560.
560.
969.
501.
0.8
0.7
1.0
0.0
0.0
0.6
0.6
1.7
0.6
0.0
0.0
0.0
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0.0
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0.0
.
0.0
0.0
0.4
0.3
0.1
0.0
0.4
0.0
0.0
0.1
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0.0
0.0
0.0
0.2
0.2
2.2
1.8
2.2
2.2
1.3
2.2
1.2
0-7
1.7
2.3
2.6
1.8
•
1.1
2.B
2.3
3.0
2.5
2.7
2.1
2.2
2.2
i.a
2.2
1*2
1.2
0*4
0.6
2.1
2*3
139
123
184
86
104
178
138
154
93
162
201
292
260
179
275
218
456
2*»
151
53
98
86
72
117
94
180
199
200
114
90
138
303
160
314
322
248
325
312
290
189
481
269
375
40
52
62
273
224
277
140
123
136
180
261
192
256
320
204
172
437
320
421
167
228
385
245
156
334
371
345
426
272
362
634
396
300
240
96
144
189
232
259
224
213
309
309
629
363
315
290
606
559
382
410
792
784
678
601
571
699
688
779
485
85
112
165
607
• 80
756
316
31*
230
386
393
386
517
357
27*
241
334
160
196
336
302
275
175
317
379
550
472
331
926
4*3
930
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27*
96
176
168
1*6
2*7
18*
339
389
406
232
183
233
550
285
581
607
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613
634
517
337
890
526
707
67
68
108
555
438
522
245
211
234
339
492
336
456
581
414
312
0-50
0.09
0.06
0.33
0.96
0.11
0.00
0.00
0.17
1.30
0.47
0.12
O.J1
0.11
0*09
0.68
0.93
0.37
0.19
0.00
0.10
O.J4
0.36
0.08
0.17
0.21
0.23
0-67
0.06
0.11
0.18
0.01
0.10
0.14
0.32
0*20
0.22
5.29
2.92
1.52
0.23
0.05
O.QO
0.02
1.13
0.01
0.09
0.03
0.01
0.11
0.79
0.2*
0.12
0.41
0.41
1.04
3.91
0*80
0.41
0.29
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0.5,4
0.01
0.55
0.09
0.08
0.32
0.96
0.11
0.01
0.00
0.17
1.35
0.47
0.12
0.30
0.10
0.09
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1.01
0.33
0.14
0.00
0*10
0.23
0.39
0.09
0.19
0.22
0.23
0.70
0.06
0.12
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0.01
0.09
0.15
0.30
0.19
0.21
5.29
3.09
1.52
0.25
0.09
0.00
0.02
1.18
0.01
0.09
0.03
0.01
0.10
0.85
0.29
0.12
0.38
0.37
0.95
3.91
0.80
0.36
0.27
0.20
0.59
0.01
-------
GO
GO
71370
71370
72070
72*70
72*70
72770
72770
72770
73070
73070
73070
73070
73070
73070
73070
73070
90*70
90*70
(0*70
80770
J0770
10770
(0770
• 0770
62370
62670
62670
63070
63070
63070
70270
70270
70670
71370
71370
71370
71770
72070
10770
10770
80770
80770
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1330
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919
1030
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1910
1610
1700
1300
1500
1630
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1000
122*
1900
1735
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900
1515
900
1030
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1000
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1330
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87.0
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7.55
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7.29
7.39
7.32
7.13
7.26
7.35
7.41
7.18
7.28
7.32
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7.68
7.70
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1.6
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262
166
178
197
161
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159
95
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137
190
223
184
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21
237
170
170
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601
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398
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650
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0.38
0.39
0.01
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0.31
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0.08
0.28
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5.62
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0.37
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0.66
0.77
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0.35
0.39
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0.32
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0.07
0.07
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0.37
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6.43
5.77
1.91
0.55
0*05
0.00
0.00
0.66
0.00
0*06
0.02
1.67
0.05
0,30
-------
OO
DATE
90970
91670
92670
92870
93070
100770
100770
100870
100970
101270
101470
101970
102070
102070
102170
102270
102270
102370
102470
110570
110570
110570
110570
110570
110570
110970
110570
110570
110570
110570
110970
110670
110670
110670
110670
110670
110670
110670
110670
110670
110670
110670
110670
61870
81170
83170
63170
63170'
83170
90670
90970
91470
91470
91670
92670
92870
93070
100770
STA-
TION
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
i
5A
5A
5A
5*
if
5A
5A
5*
9A
5A
5A
5A
5A
5A
9A
TIME
HOURS
1130
1600
144J
1920
1035
1110
1610
1150
1250
1230
1530
1155
1150
1700
1350
1110
1600
1*20
1320
930
945
1000
1030
1100
1130
1330
1400
1430
1500
1530
1600
900
930
1000
1030
1100
1130
1330
1400
1430
1500
1530
1600
1015
855
955
1055
1400
1520
1130
1015
930
1335
1650
1425
1*40
1005
1030
DEPTH
INCHES
14.50
17.00
17.00
15.50
12.00
13.50
12.00
12.00
13.79
17.00
15.00
15.00
U.50
TEMP
FAR.
14.0
8*.
e*.
««.
e:.
12.
12.
at.
11.
12.
ei.
si.
ao.
ao.
ao.
81.
82.
• 3.
62.
78.
71.
78.
76.
76.
78.
78.
78.
76.
76.
78.
78.
76.
76.
76.
76.
76.
76.
76.
76.
76.
76.
76.
76.
88.
84.0
66.0
87.0
88.0
87.0
60.0
85.0
86.
67.
64.
64.
84.
62.
82.
PH
7.08
7.14
6.61
7.06
7.22
7.20
7.19
7.21
7.26
7.27
7.2*
7.21
7.3*
7.29
7.17
7.33
7.62
7.6*
7.59
7.56
7.41
7.15
7.34
7.32
7.36
7.31
6.98
7.17
7.52
7.23
7.29
7.38
7.44
7.32
7.29
7.13
7.14
7.04
6.89
6.96
1.75
7.12
7.23
7.05
7.09
6.96
7.30
7.18
7.42
7.30
6.94
6.64
6.68
7.02
7.06
SULFIOE
ACTIVITY
M.V.
505.
460.
425.
520.
475.
470.
445.
310.
175.
»S5.
360.
»55.
460.
430.
415.
305.
120.
360.
420.
430.
190.
410.
420.
390.
435.
450.
370.
330.
460.
435.
429.
410.
470.
535.
360.
435.
345.
305.
310.
280.
580.
520.
535.
530.
532.
536.
530.
540.
465.
520.
500.
440.
510.
520.
524.
0.0.
M6/L
0.7
1.1
1.4
1.1
2.5
2.5
1.1
2.0
1.1
2.6
1.*
1.2
1.4
0.7
0.9
1.1
1.3
0.9
1.5
1.*
1.4
1.3
1.5
1.4
1.5
1.6
2.*
2.4
2.3
2.4
0.6
0.2
0.8
0.7
0.6
0.7
1.1
2.3
2.1
2.3
2.5
2.7
2.8
1.8
0.1
1.6
2.4
2.4
2.3
1.3
2.1
2.1
3.6
3.7
3.6
2.8
2.7
BOD5
MS/L
261
39
42
153
141
116
105
443
60
60
72
30
321
382
168
141
207
285
,144
132
214
231
COD
MG/L
304
117
177
257
191
250
795
121
176
185
181
526
662
187
357
309
63
193
310
E»OD
MG/L
550
107
76
251
211
196
114
934
145
117
146
63
652
694
317
276
420
516
262
240
361
401
STANDARD
SULFIDES
MC/L
0.01
0.00
0.00
0.0*
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0*00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.09
o.oo
0.00
0.00
0.00
0.00
0.00
0.05
0.04
0.08
0.09
0.09
0.21
0.05
0.15
0.00
0.02
0.01
0.00
0.04
0.06
0.07
EFFECTIVE
SULFIDES
MO/L
0.01
0.00
0.00
0.0*
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
o.oo
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.07
0.00
0.00
0.00
0.00
0.00
0.00
0.05
0.04
0.09
0.10
0.10
0.23
0.05
0.15
0.00
0.02
0.01
o.oo
0.04
0.05
0.06
-------
100770
100170
100>70
100970
101270
101*70
101970
102070
102070
102170
102270
102270
102370
102*70
• 1170
13170
13170
13170
83170
63170
90170
90970
91*70
91*70
91170
92*70
92470
93070
100770
100770
100(70
100(70
100970
101270
101*70
101970
102070
102070
102170
102270
102270
102370
102*70
(1170
(1(70
(3170
(3170
(3170
(3170
(3170
91*70
91*70
90170
90170
90(70
92*70
92470
92(70
93070
100770
100770
190170
100(70
9A
9A
JA
5*
9A
9A
iA
9A
9A
9A
9A
9A
9A
9A
59
58
96
9B
56
98
56
96
56
56
58
96
96
96
96
96
96
96
96
96
98
96
96
96
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96
98
98
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6
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7A
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19*9
10*9
1630
1139
11*0
1*99
1100
1020
1905
1199
1009
1*90
1109
1209
1010
8*9
9*9
1049
13*9
1910
1120
1000
919
1319
1649
1*19
1*39
1000
1029
19*0
10*0
1*19
1130
1139
1*90
1099
1019
1900
1150
1000
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1100
1200
900
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1019
1100
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1930
1019
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7.21
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7.08
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7.14
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7.20
7.62
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7.16
7.23
7.05
7.02
7.03
7.30
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6.78
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7.80
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7.19
8.60
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6.97
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-------
SELECTED WATER
RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
1. Report No.
3. Accession No.
w
4. Title
Instream Aeration to Control Dissolved
Sulfides in Sanitary Sewers
Author(s)
Cooper, ,;..A., Jr.
9. Organization
de Laureal Engineers, Inc.
New Orleans, Louisiana
Under contract to Department of Sanitation
Jefferson Parish, Louisiana
Environmental Protection Agency
5. Report Date
6.
8. Performing Organization
Report No,
10. Project No.
11010 ELP
. Contract/Grant No.
WPKD 121-01-68
13. Type of Report and
Period Covered
12. Sponsoring Organization
15. Supplementary Notes
Environmental Protection Agency
Report Number EPA-670/2-73-024
16. Abstract Field studies were conducted employing full scale prototypes of four aeration
devices installed in a sanitary sewage collection system. The devices used included an
In- l:ur: Venturi aspirator, an in-lire Yori,ex-..,hear aspirator, an air-lift pump, and Ven-
turi aspirated U-tubes. Only the Venturi aspirated U-tubes proved to be satisfactory
under the conditions of this' study. The U-tube installed on the end of a sewage force
main reduced dissolved sulfides, at a sampling station 1500 ft downstream, from ,30 mg/1
to .02 mg/1(equivalent to a 12 min detention). Additionally, the U-tube virtually elim-
inated the stripping of H^S in the discharge manhole where a severe odor problem and
corrosive attack had existed. Oxygen demand in the force main immediately upstream of
the U-tube averaged 2.5 mg/1. Oxygen transfer in the U-tube averaged 5.1 mg/1 with re-
sidual dissolved'oxygen in the effluent averaging 2.6 mg/1.
As installed, and with oxygen transfer averaging 5«1 mg/1, no modification of existing
pumps was required. Higher transfer concentrations approaching 7 mg/1 were obtained
irith Venturi aspiration, but resulted in increased pump head requirements. Transfer
concentrations up to 8 mg/1 were obtained with forced air injection, but d^a not appear
'o justify the added cost of blowers and greatly increased pump head requirements.
\To maintenance was required on either of the two Venturi aspirated U-tubes during two
years of continuous operation in this demonstration.
This report was submitted in fulfillment of Project Number 11010 "LP, Grant Number WPRD
,121-01-68. under the sponsorship of the Environmental Protection Agency by the Department
of Sanitation, Jefferson Parish, Louisiana, 600 Helois Street, Metairie, Louisiana 70005.
The Project Director was Hay L. Condon, Jr.
17a. Descriptors
-"-Sulfide control, -;<-odor control, -^corrosion control, aeration,
Venturi aspirated U-tube, Sanitary Waste Treatment
17b. Identifiers
oxidation, Upstream Aeration
17c. COWRR Field & Croup
18. Availability
Abstractor
19. Security Class.
(Report)
20. Security Class.
(Page)
Jr.
21. No. of
Pages
22. Price
Send To:
WATER RESOURCES SCI ENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON. D. C. 20240
institution de Laureal Engineers, Inc.
WRSIC 102 (REV. JUNE 1971)
GP 0 91 3.261
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