EPA-670/2-73-067
September 1973
Environmental Protection Technology Series
Hypochlorination of Polluted Stormwater
Pumpage at New Orleans
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Office of Research and Development
U.S. Environmental Protection Agency
Washington, D.C. 20460
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and
Monitoring, Environmental Protection Agency, have
been grouped into five series. These five broad
categories were established to facilitate further
development and application of environmental
technology. Elimination of traditional grouping
was consciously planned to foster technology
transfer and a maximum interface in related
fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
1. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL
PROTECTION TECHNOLOGY series. This series
describes research performed to develop and
demonstrate instrumentation, equipment and
methodology to repair or prevent environmental
degradation from point and non-point sources of
pollution. This work provides the new or improved
technology required for the control and treatment
of pollution sources to meet environmental quality
standards.
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EPA-670/2-73-067
September 1973
HYPOCHLORINATION OF POLLUTED STORMWATER PUMPAGE AT NEW ORLEANS
by
Uwe R. Pontius
Edgar H. Pavia, P.E.
Donald G. Crowder
Project #11023 FAS
Project Officer
Robert L. Killer
Research and Development Representative
Region VI, U.S. Environmental Protection Agency
Dallas, Texas 75201
Prepared for
Office of Research and Development
U.S. ENVIRONMENTAL PROTECTION AGENCY
Washington, D.C. 20460
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EPA Review Notice
This report has been reviewed by the Environmental
Protection Agency and approved for publication.
Approval does not signify that the contents nec-
essarily reflect the views and policies of the
Environmental Protection Agency, nor does mention
of trade names or commercial products constitute
endorsement or recommendation for use.
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ABSTRACT
Storm water from the streets of New Orleans flows to large
drainage pumping stations where it is discharged into Lake
Pontchartrain by means of long outfall canals. To reduce
the coliform density, storm water was disinfected with
sodium hypochlorite (NaOCl). Project facilities included
manufacture, transportation, storage and feeding of 100 gram/1
NaOCl. Residual chlorine analyzers were used to monitor NaOCl
dosage levels. Sixteen high volume storms totaling 109 gal. of
storm water were treated with more than 35,000 gal, of NaOCl.
Total and fecal coliform in untreated storm water exceeded
103 org/100 ml, 99% of the time. Coliform densities in
treated water were significantly reduced, with chlorine
residuals (total available) of greater than 0.5 mg/1 resulting
in 99.99% or greater removal. However, rapid recovery of
coliform levels occurred within 2k hours. Total coliform
recovered to pre-disinfection levels, but fecals did not.
The recovery did not appear to be the result of tidal influ-
ences. Long term fecal coliform levels were reduced by one
order of magnitude in each outfall canal.
The amortized cost of NaOCl manufacturing, transporting,
feeding and control facilities was $53,600/yr. NaOCl costs
for treating ~6xlO-L gal. of storm water yearly were
$200,300. This resulted in a treatment cost of $.000051/gal.
This report was submitted in fulfillment of Project # 11023
FAS under the sponsorship of the U.S. Environmental Protection
Agency.
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CONTENTS
Section No.
I
II
III
IV
VI
VII
VIII
IX
X
XI
XII
XIII
XIV
XV
XVI
Title Page No
Conclusions ^
Recommendations *
£
Introduction D
Description 3 History, and 11
Development of the New Orleans
Drainage System
Design and Construction of is
Disinfectant Facilities
Transportation Equipment 37
Sodium Hypochlorite Storage 39
Facilities
NaOCl Disinfection Facilities 42
Evaluation Program 59
Microbiological Aspects of Storm 122
Water and Disinfectants
Economics
Acknowledgments
References
130
135
136
Project Patents and Publications 139
Glossary and Abbreviations 140
Appendices 143
IV
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FIGURES
Figure No. Page No,,
1 Map of New Orleans and 7
Lake Pontchartrain
2 Cross Section of New 12
Orleans
3 Map of Present Day Drainage 15
System
4 DPS #3 Exterior View of 16
Discharge Side
5 DPS #3 Interior View 16
6 Pumping, Rainfall, and 21
Coliform Record - DPS #7 1963
7 Averaging Tank and Reactor 23
8 NaOCl Manufacturing Plant 25
9 Flow Sheet - NaOCl Manufacturing 27
Plant
10 Control Panel at NaOCl 28
Manufacturing Plant
11 NaOCl Reactor 31
12 NaOCl Transport Trucks 37
13 NaOCl Storage and Pumping 44
Facilities DPS #3
14 NaOCl Supply Header and 44
Discharge Nozzles
15 DPS #3 and #4 - Flow Sheet 45
NaOCl Feeding Facilities
16 NaOCl Feedline DPS #4 46
17 DPS #7 Flow Sheet NaOCl 48
Feeding Facilities
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Figure gggg.
18 St. Charles DPS - Flow Sheet 50
NaOCl Feeding Facilities
19 Cross Section of St. Charles 51
Reaction Basin
20 St. Charles DPS - Reaction Basin 52
21 DPS #7 - Residual Chlorine 53
Analyzer
22 St. Charles DPS - NaOCl Control 55
Panel
23 Automatic Water Sampler - Interior 57
View
24 Exterior View of Metal Building 58
25 DPS £7 Bacterial and Physical 61
Parameters 5 Year Base Period
Evaluation
26 Schematic Diagram of Drainage 66
System Involved in Project
27 Pre-Construction Evaluation 69
Project Sampling Points
28 DPS £7 - Pre-Construction 70
Evaluation Program - Bacterial,
Rainfall, and Ivater Pumped Data
29 Orleans Ave. Canal (DPS #7) - 72
Pre-Construction Evaluation
Program-Total Coliform Histogram
30 Orleans Ave. Canal (DPS #7) - 73
Pre-Construction Evaluation
Program-Suspended Solids Histogram
31 Orleans Ave. Canal (DPS #7) - 74
Pre-Construction Evaluation
Program-Dissolved Oxygen
Histogram
VI
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Figure Page
32 Orleans Ave. Canal (DPS #7) - 75
Pre-Construction Evaluation
Program Temperature Histogram
33 Pre-Construction Evaluation 78
Program - Total Coliform -
Arithmetic Mean vs Time
DPS #3, 4, and 7 Discharge
34- Pre-Construction Evaluation 79
Program - Suspended Solids -
Arithmetic Mean vs Time
DPS #3, 4, and 7 Discharge
35 Pre-Construction Evaluation 80
Program - Dissolved Oxygen -
Arithmetic Mean vs Time
DPS #3, 4, and 7 Discharge
36 Pre-Construction Evaluation 81
Program - Temperature -
DPS #3, 4, and 7 Discharge
Arithmetic Mean vs Time
37 DPS #7 Pre-Construction 82
Evalution Program - Parameter
Levels - % vs Day
38 Post-Construction Evaluation 91
Program - Storm Water Sampling
Points
39 London Ave. Canal (DPS #3 S 4) 96
Total Coliform Levels 5 Year
Base Period, Pre-Construction and
Post-Construction Evaluation Program
40 London Ave. Canal (DPS #384) 97
Fecal Coliform Levels 5 Year Base
Period, Pre-Construction and Post-
Construction Evaluation Program
ill Orleans Ave. Canal (DPS #7) d8
Total Coliform Levels 5 Year Base
Period, Pre-Construction and Post-
Construction Evaluation Program
Vll
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Figure Page_
H2 Orleans Ave. Canal (DPS #7) 99
Fecal Coliform Levels 5 Year Base
Period, Pre-Construction and Post-
Construction Evaluation Program
43 St. Charles Reaction Basin (St. 1,00
Charles DPS) Total Coliform Levels
5 Year Base Period, Pre-Construction
and Post-Construction Evaluation
Program
44 St. Charles Reaction Basin (St. 101
Charles DPS) Fecal Coliform Levels
5 Year Base Period, Pre-Construction
and Post-Construction Evaluation
Program
45 DPS #3 Storm Aftergrowth Study 106
46 DPS #7 Orleans Ave. Outfall Canal 107
47 DPS #7 Storm Profile Physical 111
Results Nov. 13, 1972
48 Storm Profile Chemical Results
Nov. 13, 1972
49 DPS #7 Storm Profile Bacterial 113
Results Nov. 13, 1972
50 DPS #7 Post-Construction Evaluation 116
Program Average Total Suspended
Matter Initial and Final Samples
51 Point A - Sampler Inlet at DPS #7 118
52 DPS #7 - Post-Construction Evaluation 1-20
Program Storm Profile Aftergrowth
Study
53 Bacterial Growth Curve 123
Vlll
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TABLES
Table No. Page No.
1 Average Rainfall: 1967- 13
Aug. 1972
2 Capacities of Drainage Pumping 17
Stations
3 NaOCl Plant Equipment and 33
Material List
4 Aging Characteristics of Stored 35
NaOCl
5 Bacterial Percentile Levels: 63
5 Year Base Period
6 Rainfall and Water Pumped 65
Frequencies
7 Bacterial Percentage Levels: 77
5 Year Base Period vs Pre-
Construction Evaluation
8 Means and Standard Deviations 85
Pre-Construction Data 22
Month Analysis
9 Coliform Correlation Coefficients 87
10 Post Construction Storm Water 93
Treatment Episodes
11 DPS #7 - Pre and Post-Construction 95
Evaluation Program: Means and
Standard Deviations of Chemical
and Physical Parameters
12 DPS #3 - Pre and Post-Construction 102
Evaluation Program: Means and
Standard Deviations of Chemical
and Physical Parameters
13 DPS #4 - Pre and Post-Construction 103
Evaluation Program: Means and
Standard Deviations of Chemical
and Physical Parameters
IX
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Table Uo. Page Mo.
14 St. Charles - Pre and Post- 104
Construction Evaluation Program
Means and Standard Deviations of
Chemical and Physical Parameters
15 DPS §3 Storm Sampling, Bacterial, 105
Chemical, and Physical Results
16 DPS #7 - Storm Sampling, Bacterial, 108
Chemical, and Physica'l Results
17 DPS #7: Volumetric Time Delays HO
13 DPS #7 - Maximum Coliform Reduction 117
for Sixteen Storm Profiles
19 Fixed Costs: NaOCl Manufacturing 131
Plant
20 Average Cost of Manufacturing 132
NaOCl
21 Fixed Costs: NaOCl Feeding 132
Facilities
22 Fixed Costs: Chemical Feed 133
Systems
23 Total Fixed Costs 133
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SECTION I
CONCLUSIONS
1. Demonstration of the feasibility of reducing total coliform
and fecal coliform levels in large volumes of storm water
by chemical disinfection and of the effectiveness of
utilizing open channels in populated areas as treatment
facilities met with unqualified success. It was also possible
to reduce the coliform levels of storm water discharged into
the outfall canals. However, recovery of coliform levels
after 24 hrs obscured the goal of coliform reduction in water
ultimately discharged to the lake since treated water could
remain in the outfall canal for days or weeks after treatment.
2. NaOCl was added to storm water during 16 high volume
storm and more than 20 low volume storms. During the 16
high volume storms, 1.0UxlO9 gals, of storm water were
treated with more than 3.5x10^ gals, of NaOCl. The largest
single treatment episode was 6.8x107 gals, of storm water
with 8.1x103 gals, of NaOCl. Sampling programs both before
and during hypochlorination were extensive with more than
2600 water samples taken for analysis. The resulting data
set exceeded 26,000 items.
3. Pre-Construction Sampling Programs indicated that 99% of
the total coliform densities in the storm water reaching the
pumping stations were greater than the 1,000 org/100 ml
recommended for body contact recreation areas by the Louisiana
State Board of Health. Fecal coliform densities were also
high with 99% greater than 100 org/100 ml.
4. From a consideration of the 16 high volume storms, chlorine
residuals greater than 0.5 mg/1 resulted in 99.99% or greater
reduction of bacterial densities. For several storms minimum
bacterial densities after disinfection were 100 org/100 ml for
total coliform, and <10 org/100 ml for fecal coliform.
5. Upon cessation of disinfection, coliform bacterial levels
in the outfall canals recovered within 24 to 30 hours. Total
coliform recovery levels of 106 org/100 ml were comparable to
those normally found in the outfall canals. Fecal coliform
recovery levels of 10 org/100 ml were approximately two
orders of magnitude less than normal endogenous levels. Tidal
influences did not appear to be a factor.
6. The coliform bacteria surviving disinfection are on the
logarithmic growth phase and the declining growth phase for
the first 24 to 30 hours. This can result in rapid recovery
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of the bacterial population to that level normally found in
the outfall canal. This rapid recovery changes significance
of the coliform levels. Their use as indicators of possible
pathogenicity of the storm water is obscured once disinfection
has occurred.
7. Since there are over lOxlO5 cu ft of water and associated
benthos in most of the outfall canals, it is not economically
possible or ecologically desirable to keep a chlorine
residual in the outfall canal at all times tc prevent coliform
level recovery. Also, pathogens are not likely to reproduce
in the harsh environment encountered in the outfall canals.
8. With recovery of indicator bacteria after disinfection,
the environmental conditions in the outfall canals dictate
the levels and viability of pathogens in the disinfected
storm water. The important environmental considerations are:
(1) temperature, (2) interference of growth due to competing
microorganisms, (3) time since introduction of microorganisms,
(4) the initial and subsequent effects of substances such as
NaOCl or other inhabiting chemicals either from natural or
manmade sources, and (5) the presence of solid materials in
the water which can shelter the microorganisms from attack.
9. BOD, COD and suspended solids levels in the outfall
canals indicated that 99.5% of the BOD values <50 mg/1,
97.7% of the COD values <175 mg/1, and 95.1% of the suspended
solids levels <100 mg/1. The majority of values which
exceeded these levels occurred just after initiation of pumping.
10. Long term levels of fecal coliform in the outfall canals
were reduced by one or more orders of magnitude at each
pumping station where NaOCl was added. Long term total
coliform levels were approximately the same as pre-disinfection
values, except for a one order of magnitude reduction at
one pumping station where all storm water was disinfected.
11. The automatic, continuous, sodium hypochlorite (NaOCl)
manufacturing plant, utilizing a patented process, is
capable of producing 1,000 gal./hr of 120 gram/liter NaOCl
under atmospheric conditions. This method of manufacture
proved to be extremely safe and reliable during the project.
12. The two, 3,000 gal., lined steel transport trucks were
able to maintain NaOCl stores at the pumping stations with
no difficulty. Both trucks were fully operational at the
termination of the project and appear suitable for transport
of high strength NaOCl,
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13. High strength NaOCl was stored in 20,000 gal., cylindrical,
lined steel storage tanks. The tanks were lined with white
natural rubber, flexible hard rubber, and polyethylene. The
storage tanks were in operation for four years under ambient
temperature and high NaOCl concentration conditions. During
this period no failures of any tanks have occurred. Thus,
these linings seem suitable for containment of high strength
NaOCl.
11. The field half life of the stored NaOCl, with an initial
concentration of greater than 90 grams/liter, exposed to
ambient conditions (March through August), averaged 133 days.
Thus, the use of 20,000 gals., cylindrical- linpd steel
tanks appears to be a quite satisfactory storage'method for
high strength NaOCl.
15. The intermittent pumpage of high strength NaOCl with
long term contact between pumpage results in the rapid
failure of polypropylene lined NaCCl pump and ORP cell
mountings.
16. Chlorine residual (C^R) analyzers used to indicate
treatment levels performed adequately after a continuous water
supply was installed for operation between storm pumpages.
This modification resulted in an inordinate use of buffer
chemicals for the operation of the analyzer- At present,
there do not exist any residual chlorine analyzers which
can be used intermittently on storm water without major
modification.
17. The automatic discrete water sampler designed and con-
structed for the project operated satisfactorily. However,
sampling intake heads, located in the storm water streams
with high velocities, were ineffective as the sample head
would tilt and break prime on the sample pump.
18. The addition of NaOCl at a point prior to the pumping
of storm water resulted in excellent mixing of the NaOCl
with the storm water. One location where a constriction
of flow in the outfall canal was to provide for complete
mixing was not effective as channeling of the water took
place. This resulted in inadequate mixing of the storm
water and disinfectant.
19. The addition of NaOCl to polluted storm water involves
eight major cost elements: (1) land, (2) manufacturing
facilities, (3) transportation facilities, (4) storage
facilities, (5) chemical feed systems, (6) chemicals, (7)
operation and maintenance, and (8) amortization cost.
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20. The total cost of facilities was $53,600/yp. The cost
of manufacturing NaOCl to treat 5x10^-° gals, of storm water
]5er year, with a chlorine demand of 3.5 mg/1, at a level of
1.0 mg/1 residual, is $200,300. On this basis, the average
treatment cost is $.000051/gal. of storm water.
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SECTION II
RECOMMENDATIONS
1. Disinfection should be continued in order to decrease
levels of possible pathogens even if coliform levels recover
since the environmental conditions are not favorable for
pathogen regrowth.
2. Controlled microbiological studies of the recovery
phenomenon, in situ, are indicated. Specific tests for
pathogens should be included as well as the standard coliform
procedures in order to ascertain the proper use of coliform
levels in controlling storm water discharge after disinfection
and to study the various parameters affecting pathogen removal
in treated storm water.
3. Chlorine residuals of 0.5 mg/1 should be maintained since
contact time is sufficiently long to decrease the levels of
coliform to less than the 1000 org/100 ml suggested for
body contact recreation areas by the Louisiana State Board
of Health.
4-. The point of disinfectant addition should be prior to
storm water pumpage whenever possible so that adequate mixing
will take place. This is expecially desirable from the
standpoint of rupturing large clumps of material and allowing
maximum NaOCl contact.
5. Since shut down of residual chlorine analyzers between
periods of storm water disinfection resulted in rapid failure
of the analyzers, a constant water supply should be provided
whenever this equipment is used intermittently. In addition,
the excessive cost of buffer chemicals for the machines should
be circumvented by mixing the necessary chemicals in bulk
on site, rather than using commercially available mixtures.
6. In order to decrease the adverse effects of long term
contact with high strength NaOCl, all equipment should be
flushed with water between usages, when possible. This would
be a much less expensive procedure in the long term when
considering the disparity (10:1) in the initial cost of
the polyethylene versus all titanium equipment.
7. The possibility of using ORP readings in a feedforward
loop to control disinfectant feed should be studied. Residual
chlorine feedback signals could be used as an overriding
parameter.
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SECTION III
INTRODUCTION
The project, "Hypochlorination of Polluted Storm Water Pumpage
at New Orleans"", consisted of demonstrating the use of sodium
hypochlorite (NaOCl) for disinfecting storm water pumped from
the east bank of the city of New Orleans into Lake Pontchartrain
(Figure 1). Initiated in December, 1966, the project_also
included the construction of NaOCl manufacturing, delivery, and
monitoring systems. Two extensive data acquisition and analysis
programs were carried out to evaluate the short and long term
effects of disinfection on the quality of the water subsequently
discharged to Lake Pontchartrain. The project was completed
in September of 1972.
The project had three basic purposes:
1. To demonstrate the feasibility of reducing
the total and fecal coliform count in large
volumes of storm water by chemical disinfection.
2. To demonstrate the effectiveness of utilizing
open channels in populated areas as treatment
facilities.
3. To reduce the coliform ba.cteria levels of storm
water discharged into Lake Pontchartrain, a
recreational body of water.
The feasibility of reducing the total and fecal coliform counts
in large volumes of storm water by chemical disinfection and
the demonstration of the effectiveness of utilizing open
channels in populated areas as treatment facilities met with
unqualified success. Coliform levels were reduced in the
outfall canals after treatment with no apparent deleterious
effects on surrounding, residential areas from hypochlorination.
However, the determination of bacterial levels in the sur-
rounding waters of Lake Pontchartrain with respect to the
treated water was not possible since several days to several
weeks could pass before treated water would leave the 10,000
ft long outfall canals. Since coliform levels recovered
during this time, the concept of coliform control became
obscured. In addition, the number of samples taken in the
lake were insufficient to determine the causative source of
either increase or decrease of coliform levels. This is due
to the large size of the lake, and numerous points of discharge
other than the treated water from the outfall canals. However,
levels of coliform at points of immediate discharge into the
lake were lowered, (32)
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FIGURE 1 MAP OF NEW ORLEANS 8 LAKE PONTCHARTRAIN
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FACILITIES
The project was initiated after data taken between 1961 and
1966 (Five Year Base Period) indicated that storm drainage
water being pumped from the east bank of New Orleans into
Lake Pontchartrain was grossly polluted vrith indicator
bacteria. Since an elevated level of indicator bacteria was
the only form of gross pollution demonstrated by the base
period data, it was felt that disinfection on a large scale
would be adequate to restore the .quality of the water to an
acceptable level. To accomplish this, it was decided to add
disinfectant to the storm water pumped by four drainage pump-
ing stations (DPS), DPS #3, DPS #4, DPS.#7, and St. Charles",
which are located on three outfall canals on the east bank
of New Orleans. The four DPS have a combined pumping capac-
ity of 11,050 cfs and each normally pumps in excess of
20,000,000 cfd of storm water on rainy days.
Due to the large amount of polluted water being pumped and
the concomitant requirement for large quantities of disin-
fectant, the project included the design and construction of
a NaOCl manufacturing plant to prepare the disinfectant used
during the demonstration phase. Disinfectant prepared at
the NaOCl manufacturing plant was stored at feeding facilities
located adjacent to each pumping station in the project. In
order to evaluate the effects of feeding NaOCl to the polluted
storm water, sampling facilities were installed at each
pumping station. Analytic equipment at the sampling facilities
consisted of water samplers, amperometric residual chlorine
analyzers, temperature probes, and dissolved oxygen (DO) meters,
EVALUATION PROGRAM
The first data acquisition program consisted of a 22 month
Pre-Construction Evaluation Program whose purpose was to
provide base line bacterial, chemical, and physical levels
for each canal, from which changes produced by the addition
of NaOCl could be determined. The 22 month Pre-Construction
Evaluation Program consisted of obtaining grab samples of
water in the suction bays and outfall canals at regular
intervals and analyzing these samples for applicable sanitary
parameters, i.e., total coliform, fecal coliform, chemical
oxygen demand (COD), biochemical oxygen demand (BOD), chlorine
demand (C1D), and solids. The data acquired from these grab
samples as well as that from the Five Year Base Period was
then used to generate statistics which characterized the
quality of the drainage water normally found in the system.
Upon completion of construction, a Post-Construction Evaluation
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Program continued the routine sampling of the open outfall
canals between periods of disinfectant feeding so that the
long term effects of disinfection could be determined.
Additionally, low volume storm and high volume storm profile
samples were taken. Storm sampling provided composite
samples of untreated storm water in the suction bays of the
pumping station and chlorinated samples from the discharge
side after disinfection during low volume pumping episodes.
The composite samples were evaluated immediately. When
possible, portions were then stored and sampled again at
24 hour intervals for three days in a bacterial aftergrowth
study. A storm profile consisted of numerous samples taken
prior to and after the addition of the disinfectant during
periods of high rates of storm water pumpage. One storm
profile aftergrowth study was performed by operating a
sampler at the outfall canal for 30 hours, at two hour
intervals following disinfection. Additionally, samples
were taken in Lake Pontchartrain weekly during the
Pre-Construction Evaluation Program and after storms during
the Post-Construction Evaluation Program.
RESULTS
Weekly sampling during the post-construction period indicated
that few changes had taken place in the outfall canals and
suction bays of the various pumping stations in the project
since the Pre-Construction Evaluation Program. There were
minor changes of the chemical and physical parameter levels,
but these were within the range of the pre-construction base
lines. Total coliform levels at DPS #3, #4, and St. Charles
remained high and other parameters were of comparable values.
However, fecal coliform values in the outfall canals at all
stations between episodes of NaOCl addition showed significant
decreases from those of the Pre-Construction Evaluation Program,
Additionally, the long term total coliform level at DPS #7 has
been lowered. This trend was obvious even though rapid
recovery of indicator coliform levels in the outfall canals
occurs after residual chlorine levels disappear. However,
fecal coliform levels do not recover to pre-treatment levels.
Thus, as discussed later, the indicator significance of the
coliform group is obscured once NaOCl has been added to the
water. Pathogens are not likely to reproduce in the outfall
canals, but regrowth of non-pathogenic bacteria is a natural
and expected phenomenon. During storm profiles, bacterial
densities were greatly reduced in the storm water which had
NaOCl added to it. Removals of greater than 1014 org/100 ml
(99.99%) were demonstrated with residual chlorine levels
>0.5 mg/1. No substantial results could be gleaned from the
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lake samples since an insufficient number were taken to account
for the many factors which influence the coliform levels in
the lake.
10
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SECTION IV
DESCRIPTION, HISTORY AND DEVELOPMENT
OF THE NEW ORLEANS DRAINAGE SYSTEM
BACKGROUND
New Orleans was founded in 1718 on the banks of the Missis-
sippi River 100 miles from its mouth. Originally the land
area was an impenetrable swamp bounded by streams and lakes.
The city lay between the Mississippi River and Lake Pontchar-
train, both of which were subject to flooding during certain
periods of the year. In fact, the river overflowed its
banks and flooded the small community consisting of 66 square
blocks within the first year.
TOPOGRAPHY
The topography of New Orleans is shown in a typical cross
section through the city (Fig. 2). It can be seen that the
elevation of the city ranges from +12 ft to -8 ft msl, with
the vast majority of the land area being below +2 ft msl.
For this reason, it has been necessary to construct levees
along both the Mississippi River and Lake Pontchartrain to
Protect the city from floods. The levees along the Missis-
sippi River have a crown elevation of +25 ft msl. The levees
along Lake Pontchartrain are being raised to a level of +13
ft msl to protect the city from hurricane tides of +11 ft
msl.
RAINFALL
The erratic nature and quantity of rainfall is an additional
complication in providing adequate drainage for New Orleans.
Since 1893 when rainfall records were initiated, the average
annual rainfall for the city has been 57.54 in./yr. The
mean annual rainfall average has varied from 33.5 in. in
1917 to 79.21 in, in 1929. The average monthly rainfall
varies from 3.21 in. to 6.60 in. although monthly rainfalls
of .06 in, in April, 1915 and 24.62 in. in October, 1937
have been recorded. The months of July and August are
usually the wettest months of the year, and October and
November the dryest. During the period of this program. New
Orleans has experienced a relatively dry period. It can be
seen in Table 1 that the rainfall of 60.94 in, during 1967
and 58.34 in. in 1970 were the only annual rainfalls which
11
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CROSS SECTION OF NEW ORLEANS
FIGURE 2.
CROSS SECTION OF NEW ORLEANS
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exceeded the 78 year average during the last five years.
TABLE 1
AVERAGE RAINFALL: 1967 - AUGUST, 1972
78 YEAR AVERAGE = 57.54 in./yr
% .EXCESS OF 78
YEAR RAINFALL (in.) YEAR AVERAGE
1967 60.94 + 5.71
1968 50.70 -13.33
1969 52.11 -10.26
1970 58.34 + 1.50
1971 55.57 - 3,23
1972 37.12 (R^0 = 40.73) - 8.89
/ o
For the eight month period, January through August 1972, the
average rainfall was 8.9% below normal.
EARLY DRAINAGE SYSTEM
The development of the present drainage system began in 1893
when a group known as the Engineering Committee was organized
to develop a general plan for storm drainage of the city-
The original master drainage plan included construction of
tributary canals, pumping stations, and outfall canals to the
lakes. The main outfall canal was located at the lowest
depression between the river and the ridges, and ran across
the city from west to east before discharging into Bayou
Bienvenue and thereby to Lake Borgne. This outfall canal was
designed to carry dry weather flow and light rain drainage
water directly to Lake Borgne. It would also be used as a
header for three relief outfall canals capable of discharging
water from the main canal directly to Lake Pontchartrain.
Four pumping stations were located along the main canal:
DPS #1, #2, #3, and #5. DPS #6, and #7 were constructed along
two of the outfall canals and discharged water directly into
Lake Pontchartrain. DPS #3 has the capability to discharge
water either into the main canal (Lake Borgne) or into the
London Avenue Canal (Lake Pontchartrain). The route of
drainage water is dependent on the available capacity of the
main canal. Priority was given to the main canal for drain-
age as originally this canal required less lift. Storm water
not handled by the main canal was routed to the outfall
canals. The main canal remains in use today as the Broad
13
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Street - Florida Avenue system. DPS #3, #6, and #7 remain
in operation as three of the largest pumping stations in the
system with capacities of 4,100 cfs, 6,000 cfs , and 3,150^cfs
respectively. With this plan prepared, the Louisiana legis-
lature created a Drainage Commission in New Orleans in 1896
to finance and construct the permanent drainage system.
MODERN DRAINAGE SYSTEM
Drainage Criteria
The present storm drainage system provides for removal of
rainfall at the rate of two inches for the first hour, plus
0.5 in./hr thereafter. A storm of this intensity is normally
experienced only once each year. The present drainage system
is designed to remove this rainfall with a runoff coefficient
of 85%.
Present Drainage System
The present drainage system for the East Bank of New Orleans ,
a map of which is shown in Figure 3, is essentially a mod-
ernized version of the drainage system originally conceived
in 1896. The drainage system includes over 1,400 miles of
subsurface drainage, 225 miles of canals, and 16 pumping
stations which have a combined capacity in excess of 30,000
cfs (13,465,000 gpm). The 213 miles of canals vary in
cross section with the largest being 28 ft wide by 14 ft deep,
The majority of uncovered canals are outfall canals carrying
water from the pumping stations to Lake Pontchartrain. These
outfall canals are up to 250 ft wide and 10 ft deep. Of the
16 pumping stations, 13 are located on the East Bank of the
city. These 13 pumping stations have the capacity to pump
in excess of 18,000 cfs into five outfall canals draining
into Lake Pontchartrain. Three of these outfall canals, the
Metairie Relief Canal, the Orleans Avenue Canal, and the
London Avenue Canal lie west of the Industrial Canal. Each
individual pumping station has its own set of pumps having
different capacities. The capacities of the individual pumps
range up to 1,100 cfs and several stations have total
capacities of 6,000 cfs. The tabulation of the pumps and
pumping capacity at the pumping stations in the project
is shown in Table 2.
14
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en
LEGEND
MAJOR STREETS
WATER SHED BOUNDARY
OPEN CANALS
CLOSED CANALS
(MANAGE PUMPING STA.
CUBIC FEET
FIGURE 3, MAP OF PRESENT DAY DRAINAGE SYSTEM
-------
FIGURE
DPS #3 - EXTERIOR VIEW OF
DISCHARGE SIDE.
FIGURE 5. DPS #3 - INTERIOR VIEW
16
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TABLE 2
CAPACITIES OF DRAINAGE PUMPING STATIONS
TOTAL
STATION NO. PUMPS CAPACITY (cfs)
#3 5 4,100
#4 5 3,900
#7 6 3,150
St. Charles 4 1,000
The pumps at the pumping stations can move the rated flow
against a pool to pool head of 14 ft. This head represents
the difference in water level between the suction bay at the
pumping station and the tidal elevation in the outfall canal.
The pumping stations of the original drainage plan are still
in use. They have been updated and modernized but amazingly
still utilize some of the original pumps. An exterior and
interior view of DPS #3, located on the London Avenue Canal,
is shown in Figures 4 and 5. This station was originally
constructed in 1899 by the New Orleans Drainage Commission
and was subsequently remanded to the Sewerage and Water Board
in 1903. Today, it serves as one of the major stations in
the New Orleans drainage system. The Sewerage and Water
Board has recently placed in operation its first fully
automatic major pumping station, the St. Charles station.
This pumping station is located in the eastern part of the
city. Pumping stations crucial to the drainage system are
continuously manned. Other pumping stations are manned only
when rain is forecast or falling.
17
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SECTION V
DESIGN AND CONSTRUCTION OF DISINFECTANT FACILITIES
GENERAL
The design and construction of the facilities for this project
required much work not anticipated in the original planning
stages. Additionally, most of the equipment had to be designed
specifically for the application, e.g., the automatic samplers
located at the feeding facilities. Also, the use of high
strength NaOCl required an in depth investigation of the
performance of materials under the stringent conditions of
long periods of NaOCl contact. The construction phase
consisted of six separate programs:
1. Sodium hypochlorite manufacturing plant.
2. Chemical storage facilities at the manu-
facturing plant.
3. Sodium hypochlorite transportation equipment.
4. Sodium hypochlorite storage and feeding facil-
ities at the points of application.
5. Automatic samplers to provide refrigerated,
discrete water samples for analytical work.
6. Data acquisition and residual chlorine analyzer
installations which monitor and control disin-
fectant feed.
The NaOCl manufacturing plant designed and constructed for
this project is of a novel design which has been patented (1).
The design has resulted in a process to continuously manu-
facture high strength sodium hypochlorite under atmospheric
conditions. This method of manufacture is much safer than
those methods that have been available heretofore. The
patents on this process have been licensed to the United
States government and Sewerage and Water Board of New Orleans
for use in all pollution control work.
Each of the facilities will be discussed separately. Where
trade names of commercial products are used, their use does
not imply endorsement either by the engineer> the Sewerage
and Water Board of New Orleans or the Environmental Protec-
tion Agency.
18
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SODIUM HYPOCHLORITE PLANT
General
The decision to use high strength NaOCl as a disinfectant for
bacterially polluted storm drainage water had been made prior
to applying for federal participation. The Sewerage and
Water Board of New Orleans had by its own volition decided to
feed disinfectant to storm water being pumped by the new
St. Charles Station for the purpose of determining its
effectiveness in reducing total and fecal coliform levels.
Under the provisions of the Federal Water Pollution Control
Act of 1965, as amended, the original plan of the Sewerage
and Water Board was extended to include DPS #3, #4, and #7
which lie on the London Avenue and Orleans Avenue Canals.
Quantity and Strength of NaOCl
With the decision to utilize NaOCl as a chemical disinfectant,
investigations were started to determine the required quantity
and strength of this material in treating the storm water
pumped to the outfall canals. Provisions were made for feeding
up to 10 mg/1 of available chlorine to the storm water based
on a possible requirement for superchlorination dosages. It
was decided that water pumped during tropical storms and
hurricanes would not be treated. With this exception,
however, the capability to treat 99% of normal pumping periods
was required since swimming beaches at the lake are used
year round. Evaluation of the available space and operating
characteristics of each pumping station involved in the
demonstration program resulted in a decision to use NaOCl
in a concentration of approximately 96 gpl. Consumption
was determined by analyzing quantities of water pumped
during a five year base period, July 1, 1961 to June 30, 1966.
Pumping, rainfall, and coliform records for DPS #7 on the
Orleans Avenue Canal for 1963 are shown in Figure 6. Based
on the Five Year Base Period data, a maximum of 20,000
gallons per pumping day of 96 gpl NaOCl would have been used
at each of the pumping stations in the program. An analysis
of the wettest five day period indicated that each of the
three pumping stations originally slated to use NaOCl would
have required a total of 40,000 gallons of NaOCl. Due to
the relatively short life of commercially available NaOCl,
the disinfectant would have to be available on a very rapid
replacement basis or disinfectant of a higher strength
would be required. An evaluation of the NaOCl deterioration
curve indicated that if the disinfectant were supplied at a
19
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concentration of 120 gpl, it would normally be used before it
had deteriorated below 96 gpl. The regular suppliers of
NaOCl in the New Orleans area were contacted and their
interest in furnishing disinfectant for the project was
determined. None were interested in a short term contract
for the quantities and concentration required and the
construction of an NaOCl manufacturing plant was required.
Design of NaOCl Manufacturing Plant
The NaOCl manufacturing plant was located at the water
purification plant of the Sewerage and Water Board of New
Orleans due to the availability of personnel experienced in
handling large quantities of chlorine. Since the water
purification plant is located in a residential and semi-
commercial area, the utmost degree of safety had to be
designed into the NaOCl manufacturing plant. The final
design was for a continuous, automatically controlled manu-
facturing plant with a capacity to manufacture 1,000 gal./hr
of 120 gpl NaOCl with a storage of 40,000 gal. of finished
NaOCl at the manufacturing plant. The design criteria met
the maximum demand for NaOCl and the plant was operated
as required during the periods of lower demand to keep the
feeding facilities at the pumping stations supplied with
suitable strength NaOCl.
Process Design
NaOCl is commonly manufactured by reacting sodium hydroxide,
chlorine, and water. The reaction is exothermic and is very
sensitive to the temperature of reaction. If the temperature
of reaction exceeds a value of 86° F to 90°F, sodium chlorate,
an inert material, which is of no value for disinfection,
is formed. For this reason, high strength NaOCl is commonly
manufactured in a batch type operation with manual control
of the addition of chlorine. The reaction takes place
either in concrete or rubber lined vats with cakes of ice
or refrigerant coils being used to absorb the heat of reaction.
When ice is used, it provides part of the water required
for the manufacture of the finished product. The batch
operation is wholly dependent on the operator for the control
of chlorine addition and for the quality of the finished
product. Due to the intermittent high level demand for the
disinfectant, the process-was designed to provide for the
manufacture of NaOCl on an automatic, continuous basis.
Investigations of the commonly available reactors for con-
tinuously manufacturing high strength NaOCl revealed that
20
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FIGURE 6. PUMPING, RAINFALL, g COLIFORM RECORD - DPS #7 1963
-------
these reactors generally operated under pressure. Due to the
location of the plant, it was felt that this would be an
undesirable feature from the standpoint of safety and should
be avoided if possible. Thus, it was felt that the process
design should have the following features:
1. It would operate at atmospheric pressure.
2. It would control the temperature of the
reaction so that it would never exceed 86°F.
3. It would be constructed of materials resistant
to water, sodium hydroxide, liquid and gaseous
chlorine, and sodium hypochlorite.
The requirement that the reactor operate at atmospheric
pressure implies that the chlorine must react completely
prior to reaching a free surface. In batch type operations,
chlorine is usually introduced into the reaction tank approxi-
mately 8 feet below the surface. Pilot studies were
carried out and indicated that a horizontal reactor providing
an equivalent retention time would suffice. However, an
averaging tank was placed at the end of the reactor to
provide additional mixing time. (Fig. 7)
Liquid chlorine is used directly from tank cars, without
vaporization to gaseous chlorine, and blended with a pre-
viously diluted 14% NaOH solution. This procedure results
in a reduction of the heat of reaction of approximately 16%.
The heat generated by chlorine when combined with NaOH is
526 BTU per pound of liquid chlorine. Production of 120 gpl
NaOCl, at a rate of 1,000 gal./hr results in the generation
of 527,052 BTU which is equivalent to 44 tons of refrigeration,
Since the reaction to form 120 gpl NaOCl requires chlorine
to be added to a 14% solution of NaOH, the possibility of
using precoo'led 14% NaOH as the heat sink was considered.
It was calculated that 14% NaOH would have to be cooled
to 14°F to provide a sufficient heat sink to absorb the heat
of reaction. However, 14% NaOH has a crystallization
temperature of 11°F, and it was deemed that the three degree
difference between the two temperatures did not provide an
adequate safety margin. Thus, another heat sink had to be
found. It had been previously determined that the finished
NaOCl would be cooled to 60°F in order to improve its life
span. Thus, adding a sufficient amount of manufactured and
cooled NaOCl to the reacting mixture served as the second
heat sink. Using a recirculation of 2.23 volumes of
finished NaOCl at 60°F, it was found that the 14% NaOH
solution would only have to be cooled to 60°F for the
combination to provide a sufficient heat sink. This design
22
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Co
FIGURE 7. AVERAGING TANK 8 REACTOR
-------
has eliminated the requirement for either ice or refrigeration
coils to be present inside the reactor. By utilizing reacted
NaOCl and 14% NaOH as heat sinks at a relatively high tem-
perature of 60°F, it was possible to use commercial air
conditioning chillers rather than heavy duty industrial type
refrigeration machines. This achieved a considerable saving
in cost, both in equipment and installation. A second
benefit of the relatively high temperatures of the heat sinks
is that it will not be necessary to operate the chillers for
approximately six months out of the year. During the winter
months, a favorable temperature differential between the
reacted material and the potable water distribution system
will provide the needed refrigeration capacity. Thus, during
that portion of the year when the temperature of the water
in distribution mains is below 60°f, the cost of cooling will
only be the cost of pumping and filtering water from the
distribution mains. Utilizing water from the distribution
system, the NaOCl plant can operate with a total connected
load of 39 hp and demand load of 24 hp. These levels are
approximately 25% of the total connected and demand load
when the refrigeration chillers are in operation.
The NaOCl plant was designed to be completely outdoors with
the exception of a small control house containing the control
cabinet, a small laboratory for quality control and a desk
for the chemist-operator. The NaOCl plant is located on
one concrete slab 55 ft by 24 ft which contains all the
equipment of the plant with the exception of the storage
and unloading facilities. The NaOCl manufacturing plant is
shown in Figure 8. To provide for receipt of the 50% NaOH
and chlorine, an existing railroad siding was extended to the
NaOCl manufacturing plant. The 50% NaOH unloading facilities
are designed to unload a 10,000 gal. tank car of 50% NaOH in
50 min. The loading facility for the finished NaOCl has the
capacity to load a 3,000 gal. tank truck in 15 min. These
features are necessary to provide for quick loading and
unloading during periods of high NaOCl usage.
With the entire plant outdoors, .the requirement for ventil-
ation to remove any escaping chlorine gas was eliminated.
The outdoor location is considered adequate for plants in
areas where the temperature rarely drops below freezing.
However, if a plant of this type were to be constructed in
the freezing zone, protection against freezing would have
to be provided for the pneumatic control system.
-------
NJ
Cn
FIGURE 8. NaOCl MANUFACTURING PLANT - This view shows the entire NaOCl manufacturing
plant. The C12 supply car is in place on the railroad siding. The un-
loading facilities can be seen adjacent to the railroad track in front
of the Cl~ car. The NaOH storage tanks can be seen in the background.
The finished NaOCl storage tanks are in the lower right of the picture.
-------
Control System
The control system finally selected for this plant is shown
on the process flow sheet in Figure 9. The control system
basically consists of locally mounted sensing devices,
electrical to pneumatic converters and pneumatically con-
trolled actuators. The converters send signals to the
control panel which is shown in Figure 10. From the control
panel, transmitters send pneumatic signals to the control
elements, such as valve positioners, to complete the loop.
All flow meters are magnetic. Required information is
recorded on four inch strip chart recorders mounted on the
control panel. To provide sufficient resolution of the
parameters during the manufacturing process, the speed of
the strip chart recorder was selected at two in. per hour.
The main problem in designing the control system was finding
equipment constructed from materials capable of withstanding
the attack of the chemicals. As a general rule the control
components, both valves and sensing devices, are constructed
of the same material as that in which they are mounted.
However, ORP cells are constructed of epoxy or PVC with
silver and platinum electrodes. The temperature sensing
probe in the NaOCl reactor is constructed of titanium.
Level sensing devices of the bubble type were used through-
out and utilized PVC piping for the bubble tube.
Operation
The NaOCl manufacturing plant is designed to be completely
automatic and operated by a single chemist-operator. From
the control panel, the chemist-operator can proportion the
blending of 50% NaOH and water for reaction to the required
NaOCl concentration. This proportion can be set from the
control panel and is maintained by a ratio controller. In
addition to the ratio controller, oxidation reduction
potential (ORP) cells were originally used to compensate for
variation in raw materials and/or finished product. The
ORP was determined by the strength of the finished product
and the excess alkalinity desired.
Normal practice in NaOCl manufacturing plants has been to
control the chlorine feed and the excess alkalinity by
measuring the ORP of the finished product. In batch type
operations, an ORP sensing device is placed in the reaction
tank to continuously measure the ORP of the reacting solution.
Using this value of ORP, the plant operator varies the
chlorine feed until the desired ORP value is attained. In
26
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CO
FIGURE 9. FLOW SHEET - NaOCl MANUFACTURING PLANT
-------
, i ;•
FIGURE 10. CONTROL PANEL AT NaOCl MANUFACTURING PLANT
-------
continuous manufacturing plants, the ORP of the finished
product is monitored and the volume of chlorine feed is
determined from this reading. This feedback use of ORP
makes it possible to correct for over or under chlorination
by changing the input chlorine feed. However, it does not
indicate the presence of chlorate formation which is accom-
panied by an excessive temperature rise. Due to this
important effect, reactor temperature was used to provide
an overriding control for the ORP parameter. Also, rather
than using ORP information only in a feedback loop, the
possibility existed of using feedforward ORP information.
This was. accomplished by providing an ORP sensing device
in the line carrying the mixture of cooled, recirculated
NaOCl and 14% NaOH to sense the chlorine requirement of the
incoming mixture. Thus, three systems of chlorine feed
control by ORP were available.
1. The ORP of the finished product. (Feedback)
2. The ORP of the solution entering the reactor.
(Feedforward)
3. The ORP of the solution entering the reactor
in combination with the ORP of the finished
product. (Feedforward control with feedback
monitor and override).
A fourth method of chlorine control was also provided and
is referred to as the ratio system. The ratio system
controls the rate of chlorine addition by monitoring the
flow rate of unreacted 14% NaOH.
In all four systems, the temperature of the reacted product
is continuously monitored in the mixing tank. If the tem-
perature in the reactor pipe exceeds a preset value of 86°FS
both the chlorine valve and the 14% NaOH valve are immediately
shut. This allows only cooled, recirculated NaOCl to enter
the reactor and act as a heat sink until the temperature
drops to 78°F. At this point, control will be returned to
the chlorine control system set by the operator. A flow
sheet of the final NaOCl manufacturing design is shown in
Figure 9.
Shortly after exposure to high strength NaOCl, the ORP cell
experienced rapid failure of the resin bonding the electrical
ce'lls to the body of the assembly. After several replacements,
it was decided to abandon the ORP cells and to rely entirely
on the ratio control system. This has presented no problem
in the manufacture of high quality NaOCl. The temperature
override was retained and provides adequate over chlorination
29
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and chlorate formation protection for the system.
MATERIAL SELECTION
Because of the chemical activity of NaOCl, the construction
design was greatly affected by the process design. Many of
the features of the process and construction design were
dictated by the availability of materials which could_withstand
the highly corrosive products while being reasonable in cost.
Many materials were studied for use in the reactor, NaOCl
piping, and NaOCl storage facilities. Since the reactor
was the most critical of the three components, materials for
its construction were investigated first. The material
finally selected would have to withstand the attack of both
dry and wet forms of liquid and gaseous chlorine as well as
NaOCl.
The only metals found to be resistant to the finished NaOCl
were duriron, titanium, tantalum and platinum. Since the
plant was designed to be operated outdoors, it would be
subjected to the full range of normal ambient temperatures
in New Orleans, 14°F to 95°F. Thus, the use of duriron was
discarded because of its brittleness and sensitivity to
temperature changes. Titanium, the least expensive of the
remaining metals, was investigated thoroughly. However,
tests showed that if the titanium oxide film which forms on
the surface of the metal is removed and subsequently exposed
to dry chlorine gas, the metal will flash, causing a fire.
For this reason, titanium was discarded as a material for the
reactor. Tantalum and platinum were eliminated from con-
sideration due to their cost.
Several plastics, both of the pure and "fibrous" glass
varieties, were investigated. It was found that the fibrous
varieties were dependant on the quality of the resin binding
the glass for resistance to chemical attack. It is also
difficult to manufacture this material with reasonable
assurance of quality. The first pure plastic investigated
was polyvinlychloride (PVC) which is commonly used to contain
and transport NaOCl. However, this material is very brittle
and has low beam strength. Thus, PVC was not deemed a
suitable material for the reactor- After futher investigation,
polyvinyllidene fluoride' (kynar) lined steel pipe was selected
for use^as the reactor. The reactor is shown in Figure 11.
It consists of a polyvinlyidene fluoride sparger tube carrying
the liquid chlorine into a polyvinylidene fluoride lined pipe
where the chlorine is discharged into the mixture of preceded
NaOCl and 14% NaOH. At the design rates of flow, complete
mixing should be achieved in the reactor almost immediately.
However, to provide additional mixing and to insure against*
30
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r OUTLET
SODIUM HYPOCHLORITE REACTOR
FIGURE 11.
NaOCl REACTOR
-------
any gaseous chlorine passing through without reacting, a
perforated baffle was placed at the midpoint of the reactor
tube. At a flow of 51 gal./min, retention time in the
reactor tube is 64 sec. The reacted material then passes
into an averaging tank which provides a liquid head of 8 ft
to insure against any unreacted chlorine reaching the surface
and discharging into the atmosphere. Polyvinylidene fluoride
lined pipe was used for all NaOCl lines and 14% NaOH lines.
Ordinary steel pipe was used to carry water from the water
distribution system to the NaOCl plant. The materials used
for construction of the major plant components are listed in
Table 3.
CONSTRUCTION OF NaOCl MANUFACTURING PLANT
The construction of the NaOCl manufacturing plant took
approximately 10 months. From a mechanical standpoint, the
NaOCl manufacturing facility was a relatively simple plant
to construct. Once the contractor gained experience in
making up the lined pipe joints, piping erection was speeded
up considerably. The other phases of the construction
proceeded smoothly.
Preliminary testing of the NaOCl manufacturing plant began
on April 1, 1969 in accordance with the startup schedule.
The NaOCl plant was first operated utilizing only water
throughout the plant to check for leaks and test all pumps,
control valves, and control functions. During this period
all automatic controllers were placed on their set points
and tested. This initial procedure was accomplished during
the first two weeks of April, 1969. After the NaOCl plant
was completely tested by the utilization of water, the first
tank of 50% NaOH was ordered and received. The startup
procedures called for utilizing only 50% NaOH in the plant
until all control functions pertaining to this material were
operating perfectly. During this period the NaOCl plant
was operated to dilute 50% NaOH to 14% NaOH. The 14% NaOH
passed through the reactor to a storage tank. During this
time approximately 12,000 gal. of 14% NaOH were prepared.
When all control functions were operating properly, the
plant was shut down and thoroughly cleaned. On May 21, 1969,
the NaOCl plant first utilized chlorine and 14% NaOH to
prepare finished NaOCl. Preliminary testing continued during
the summer of 1969. During the period of the project, the
NaOCl plant has operated satisfactorily and was able to
produce its design quality of high strength NaOCl. NaOCl of
strengths as low as 100 gpl and as high as 150 gpl were
prepared to test the flexibility of plant design.
32
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TABLE 3
NaOCl PLANT EQUIPMENT AND MATERIAL LIST
ITEM
50% NaOH Storage Tanks
50% NaOH Pumps
50% NaOH Piping
50% NaOH Valves
H^O Pumps
H20 Piping
H20 Valves
11% NaOH Piping
14% NaOH Heat Exchangers
11% NaOH Valves
C12 Piping
Cl Valves
NaOCl Pumps
NaOCl Piping
NaOCl Reactor
NaOCl Heat Exchanger
NaOCl Valves
NaOCl Tanks
Control Valves
H20
NaOH
NaOCl
Electric Motors
Electric panels, motor
controllers, push buttons,
pilot lights, etc.
Refrigeration Equipment
MATERIAL £ CONSTRUCTION
Welded Carbon Steel with epoxy
interior lining.
All iron, centrifugal
Seamless Carbon Steel, Sch. 10
SS ball valves
All iron, centrifugal
Seamless Carbon Steel, Sch. 10
SS ball valves
Polyvinylidene fluoride lined
carbon steel.
Plate Type - 301 S.S.
SS ball Valves
Seamless Carbon Steel, Sch. 80
SS Ball Valves
Polypropylene lined Steel, centri-
fugal
Polyvinylidene fluoride lined
carbon steel.
Polyvinylidene fluoride lined
steel, polyvinylidene - solid
PVC lined fibrous glass
Plate Type - Titanium
Teflon lined, SS ball valves
Welded Carbon Steel, rubber lined
Cast Steel, ported
Cast Steel, ported
Polyvinylidene fluoride lined
Saunders Diaphragm
Epoxy encapsulated
Standard NEMA construction in Cu.
free, cast Al housings.
Standard Air Conditioning Type
Packaged Chilled Water Systems
33
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Evaluation of NaOCl Manufacturing Plant
The NaOCl plant has demonstrated its capability to manufac-
ture a consistant product of high quality without discharging
gaseous chlorine to the atmosphere. With the unpressurized
reactor, even over chlorination has proven to be more of an
annoyance rather than a major accident. On July 19, 1969,
over chlorination occurred while setting the ORP control
system. However, rather than the usual sudden release of
chlorine to the atmosphere, only a slight bubbling on the
surface of the averaging tank was noted. Over chlorination
was not confirmed until a sample of NaOCl had been titrated.
As the temperature in the reactor increased, the temperature
override shut down the process and prevented further chlorine
from entering the reactor- It is felt that this malfunction
justified the design of the reactor to operate at atmospheric
pressure.
Some difficulty has been observed in obtaining proper mixing
in the averaging tank located at the end of the reactor. In
subsequent designs, this tank should be enlarged so that an
adequate head of finished material is maintained and complete
mixing in the averaging tank is achieved.
Several problems were encountered with the handling of the
finished NaOCl. The ORP cells that measure the strength of
the chemicals failed due to the action of NaOH and NaOCl on
the epoxy lining of the cell. Due to this failure, the plant
has been run by the chemist-operator using the ratio control
system. There have been several failures of the lining in
the reactor averaging tank and two failures of the reactor
pipe. These problems were traced to stresses caused by
vibrations generated in the mixing of the chemicals. The
averaging tank was replaced with a polyethylene tank designed
by Sewerage and Water Board personnel. The replacement tank
has performed satisfactorily. The kynar lined reactor
pipe was replaced free of charge by Resistoflex.
One problem that remained intractable was the continuing
failure of the polypropylene lined NaOCl pumps manufactured
by the Saran Lined Pipe Company. With intermittent operation,
the NaOCl ramaining in the system deteriorates and crystals
form on the pump seal faces. On subsequent operation, the
seals are damaged and NaOCl reaches unlined sections of the
pump shaft. Rapid failure of the pump follows. Tests were
conducted using a teflon seal in place of the carbon seal
and_operating life was increased from two to six months.
Additionally, the polypropylene lining covering the impeller
and casing of the pump has failed. It is possible that the
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CO
tn
TABLE 4
AGING CHARACTERISTICS OF STORED NaOCl
PART A Average Daily Decrement in NaOCl Strength [gram/I/day]
Concentration
[gram/1]
90 - 100
80 - 90
70 - 80
60 - 70
50 - 60
40 - 50
20 - 40
Storage Period
Mar 13 - Aug 2
Mar 13 - Aug 2
Apr 17 - Aug 2
Jan - Mar Apr - June July - Sept Oct - Dec Avg.
.2 .57 1.1 .56 .61
.36 .32 .84 .76 .59
.11 .33 .33 .64 .35
.3 .43 .84 .21 .44
.3 .43 .34 .41 ..37
.47 .31 .26 .35
.1 .1 -- .10
PART B Approximate Half-Life of Stored NaOCl
Initial Cone. Final Cone. Days stored Approx. Half Life
[gram/1] [gram/1]
92.9 52.5 133 149
94.3 41.1 133 130
96.5 53.2 107 120
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NaOCl attacks the lining along mechanical and thermal stress
lines. Previous experience with polypropylene lined pumps
indicates that they can be maintained for long periods of
time during continuous operation in low strength NaOCl
environments. The difficulties encountered with the poly-
propylene lined pumps are due to the highly intermittent
usage pattern and high strength of the NaOCl. The use of all
titanium pumps had been contemplated at the initiation of
the project, but the cost was prohibitive ($6,000/pump
compared to $500/pump). At present, it appears that flushing
of the entire system, piping and pumps, between periods
of use or replacement of the pumps as they fail are the
only solutions.
The aging characteristics of the manufactured NaOCl in the
field are given in Table 4. Table 4, Part A gives the
average daily decrease in strength as a function of NaOCl
concentration. These figures are based on weekly sampling
of stored NaOCl at the pumping stations. Table M-, Part B,
is the field half life (i.e. time for the concentration to
reach one half its initial value) of the NaOCl as stored in
the tanks and exposed to ambient conditions. The approximate
half life was calculated by using the average daily decrement.
The values seem comparable to NaOCl aging properties reported
in the literature (33) when the range of ambient
temperatures in New Orleans is considered during the
storage period. (60°F - 98°F air temperature)
36
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SECTION VI
TRANSPORTATION EQUIPMENT
The design of the treansportation equipment was based on the
necessity to replace NaOCl as it was utilized during the
worst five day period at each pumping station. From a con-
sideration of the pumping characteristics of the pumping
stations and chlorine demand of the storm water, the original
requirement was one of being able to transport 40,000 gals.
of NaOCl to each of three pumping stations during a five
day period. DPS #7, originally slated to feed 40,000 gals.
of chlorine, was Ir.ter redesigned to feed NaOCl.
FIGURE 12. NaOCl TRANSPORT TRUCKS
Louisiana has a legal limit of 50,000 Ibs for any over the
road vehicle. A study of available trucks indicated that
approximately 3,000 gals, of finished NaOCl would result in
a gross vehicle weight approaching 50,000 Ibs. A survey of
the routes that can be taken to the pumping stations indi-
cated that, at most, three trips per eight hour shift could
be made by one truck. Assuming 100% availability, a
37
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capacity to deliver 22,000 gals, per 24 hrs would be needed.
Based on the requirement for replenishment at_the feeding
facilities, one truck would have sufficed. Since 100%
availability of automotive equipment cannot be assumed, two
rubber lined steel tank trucks were purchased. The trucks
were standard heavy duty trucks with reinforced chassis
to carry the heavy loads. The storage tank on each truck
if 5 ft 10 in. in diameter and 16 ft 8 in. long with a
capacity of 3,000 gals. The tank is made of steel lined
with a three-ply, semi-hard, rubber lining. The tank is
designed for compressed air unloading. The air compressors
have sufficient capacity to unload a truck in approximately
30 minutes. The tank is equipped with ladders, walkways
and a manhole and meets the requirements of the Interstate
Commerce Commission cargo tank specification #M-312 MS. The
trucks are tandem trucks (International Harvester) utilizing
a single chassis for both power unit and the tank. The
trucks are shown in Figure 12. Both trucks have been used
extensively during the period of the program. The trucks
have shown signs of external deterioration in the form of
rust and peeling paint due to the harsh environment.
However, the lining on the interior of the truck tanks is
sound and both trucks were in operation at the end of the
project.
38
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SECTION VII
SODIUM HYPOCHLORITE STORAGE FACILITIES
STORAGE TANK DESIGN
The major problem of the project was presented by the storage
and handling of 160,000 gals, of 120 gpl NaOCl both at the
NaOCl manufacturing plant and at the pumping stations. While
there are many materials listed as being capable of containing
120 gpl NaOCl, it was discovered that very few had been used
for long term storage of NaOCl at this concentration. In
addition, many materials were not recommended for outdoor
use. Since NaOCl was to be stored in residential or semi-
commercial areas, the safety of adjacent properties and
residences had to be given the highest priority. In
analyzing the linings of NaOCl storage tanks then currently
in use, it was found that previous experience had been with
low strength NaOCl solutions for extended periods of time or
high strength NaOCl solutions for short periods of time.
Also, thorough flushing of the storage facility between
periods of use was the rule.
MATERIAL SELECTION
General
Since the above conditions could not be met, the investigation
was widened to include all materials capable of withstanding
NaOCl attack. Among the materials and types of construction
available were the following:
1. Rubber lined steel.
2. Solid plastics.
3. Concrete tanks with collapsible liners.
4. Fibrous glass reinforced polyester materials.
5. Polyethylene lined steel.
Each material and construction method was investigated with
respect to three main considerations: (1) a tank construction
design which would prove resistant to the highly corrosive
NaOCl for long periods of time, (2) because of the limited
39
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space available at several of the pumping stations, a
multitude of small storage tanks could not be tolerated,
and (3) it was not desirable to have NaOCl storage tanks
which would exceed the height of any surrounding residences.
These limitations were met by using two, 20,000 gal. hori-
zontal, cylindrical, steel storage tanks at each^pumping
station and at the NaOCl manufacturing plant. Since tanks
of this size were almost unheard of for NaOCl storage, each
of the available construction methods and materials was
studied to determine their adaptability to constructing
NaOCl storage tanks of this size.
Rubber Lined Steel
While, there was more experience in the use of rubber lined
steel tanks for storage of high strength NaOCl, it was found
that their performance had been very erratic. Indeed, the
suppliers of rubber lined steel tanks readily admitted that
the integrity of the tank was dependent on the workmanship
used in the application of the rubber liner to the steel.
Tanks storing 80 gpl NaOCl, used as bleach in pulp mills,
indicated some tanks had useful lives of 15 to 17 years.
Other tanks lined with the same material, applied by the
same personnel, lasted only six months to two years. The
manufacturers also admitted that the 15,000 volt spark test
was no guarantee of a proper bond between the rubber lining
and the steel. Since tanks holding 20,000 gals, of NaOCl
must be lined with several sheets of rubber, each containing
several joints, the possibility of having an incompletely
sealed tank is high. However, NaOcl storage tanks lined with
rubber had performed very capably in many cases.
Solid Plastic
Tanks made of solid plastic such as PVC or polyester resins
were also investigated. However, the low beam strength of
these materials made their construction in these sizes
impractical.
Lined Concrete Tanks
The use of concrete tanks with collapsible liners was also
investigated because concrete is known to be fairly resistant
to high strengTh NaOCl. However, the tanks were very diffi-
cult to repair if failure occurred and this type of construc-
tion was deemed unsuitable.
-------
Fibrous Glass Reinforced Polyester
Another material which had been used with some success to
store high strength NaOCl was fibrous glass reinforced poly-
ester. Investigations again brought out the importance of
good workmanship in the proper fabrication of these tanks.
The basic method is to construct a fibrous glass tank of
sufficient thickness to provide structural integrity and
then applying a NaOCl resistant resin to the interior.
However, it was found that due to the unequal thermal
coefficient of expansion between the pure resin liner and
the fibrous glass outer shell, a crazing of the inner liner
occurred. This resulted in rapid failure of the tank. Since
rather wide temperature fluctuations were expected, this
method of construction was deemed unsuitable.
Polyethylene Lined Steel
The final method of construction considered was a steel tank
lined with polyethylene sheets. This material has been used
with some success in containing high strength NaOCl as well
as other very corrosive materials. The only drawback of
this particular method of lining appeared to be an uneven
distribution of thermal stress between the steel tank and the
polyethylene lining. This uneven matching- of thermal coef-
ficients of expansion causes "bubbles" to appear in the
lining. However, no difficulties are encountered as long
as the "bubble" does not destroy the continuity of the welds
at the edge of the individual sheaths of lining.
Final Selection and Evaluation
Based on this data, the final selection resulted in four
tanks lined with white natural rubber (DPS #14 and St. Charles),
four tanks lined with flexible hard rubber (DPS #3 and plant),
and two tanks lined with polyethylene (DPS #7). The storage
tanks were in operation for approximately four years under
extreme temperature and NaOCl concentration conditions.
During this period no failures of any tanks have occurred.
Additionally, the linings of all tanks appear to be sound
as of the time of the final report.
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SECTION VIII
NaOCl DISINFECTION FACILITIES
GENERAL
Once the NaOCl has been manufactured at the plant and stored
at the pumping stations, a system was needed to deliver the
NaOCl to the storm water on a demand basis. The basic con-
cept of feeding NaOCl to bacterially polluted storm drainage
water is the same at all four pumping stations involved in
the program.
However, there are slight differences in the manner in which
the storm water reaches, is disinfected, and leaves each
pumping station. The points of application at each station
and the physical differences are as follows:
1. DPS #3 - NaOCl is fed to the storm water in the
discharge bay. This occurs prior to a constric-
tion in the outfall canal. The constriction is
used to provide mixing of the disinfectant and
storm water.
2. DPS #H - NaOCl is added to the storm water in
the suction bay and depends on the pumps of the
station to provide mixing of the disinfectant
and storm water.
3. DPS #7 - NaOCl is added in the suction bay
just prior to the pumping station. The pumps
at the station provide complete mixing of the
disinfectant and storm water.
4. St. Charles DPS - NaOCl is added to the storm
water through a submerged, perforated pipe at
the^entrance of a large, concrete lined, re-
action basin which has a retention time of
22 to 86 minutes. The reaction basin is on the
suction side of the pumps and provides a chamber
for mixing of the NaOCl and storm water.
-------
DPS #3
DPS #3 is located on the London Avenue Canal 3.03 miles from
Lake Pontchartrain. The canal is covered to the station and
open from the station to the lake. The station is equipped
with five pumps having capacities from 550 cfs to 1,000 cfs
with a total capacity of 4,100 cfs. Low volume pumpages
arriving at the station are pumped into the Florida Avenue
Canal - Bayou Bienvenue system while high volume pumpage is
directed to Lake Pontchartrain.
Disinfectant storage at the station consists of two, 20,000
gal. rubber lined steel tanks. The NaOCl feeding system
employs two polypropylene lined centrifugal pumps, each
having a capacity of 160 gal./min against a 90 ft TDH. The
installation at DPS #3 is shown in Figure 13. The disinfec-
tant feed pumps empty into a common discharge header which is
carried underground to the outfall canal. At the outfall
canal, the disinfectant line comes above ground and is
carried on a timber trestle across the outfall canal. Once
the feed line reaches the trestle, it is equipped with
nozzles which discharge NaOCl into the water across the full
width of the outfall canal. The disinfectant feed line
installation is shown in Figure 14. At the point of dis-
charge, the London Avenue Canal-'is 160 ft side. At a point
220 ft downstream, the canal narrows to 95 ft and remains at
this width for 17,050 ft before widening again to 130 ft.
Thus, a constriction in flow occurs which might have provided
sufficient turbulence for complete mixing of the disinfectant
and storm water. This assumption was not proven during the
program as channeling of the water took place rather than
turbulent mixing. The channeling resulted in inadequate
mixing of the storm water and disinfectant. Very high levels
of chlorine residual (Cl^R) occurred in parts of the canal,
while in other portions no residual was found. This is in
contrast to the excellent mixing provided by the pumps at
those stations where the disinfectant is added prior to pumping.
If possible, the feed point should be moved at this and sub-
sequent installations to a point prior to pumping. A flow
sheet of the feeding and sampling facilities at DPS #3 and
#4 is shown in Figure IS.
DPS #4
DPS #4 is located on the east side of the London Avenue
Canal at Prentiss Avenue, 1.09 mi from Lake Pontchartrain. All
43
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FIGURE 13. NaOCl STORAGE AND PUMPING
FACILITIES, DPS #3
FIGURE 14. NaOCl SUPPLY HEADER AND
DISCHARGE NOZZLES
-------
SODIUM HYPOCitt-OHITE FEEDING FACILITl
TREATMENT a SAMPIH3 FLOW
DIAGRAM - LOMDON AVE. CANAL
FIGURE 15. DPS #3 g #4 - FLOW SHEET NaOCI FEEDING FACILITIES
-------
influent lines to the canal are covered. The station is
equipped with five pumps having capacities from 300 ere to
1,100 cfs, with a total capacity of 3,900 cfs.^ A unique
feature is the pumping of low volume storm drainage to
DPS #3 and thereby into the Florida Avenue Canal - Bayou
Bienvenue System which ultimately discharges into Lake
Borgne, a large body of water east of New Orleans.
At DPS #4, two covered canals enter the suction bay. ^
canal has an invert 4 ft lower than the other. The disin-
fectant feeding facilities at DPS #4 are similar to those
at DPS #3 except that application of the NaOCl is on the
suction side of DPS #4, and thus, prior to pumping of the
storm water. The disinfectant storage and feeding system
consists to two, 20,000 gal., rubber lined steel tanks and
two polypropylene lined centrifugal pumps. The disinfectant
is fed to the storm water from a pipe located on the divider
wall of the two incoming feeder canals (Fig. 16). A flow
sheet of the feeding and sampling facilities at DPS #4 is
shown in Figure 15.
FIGURE 15. DPS #4 NaOCl FEEDLINE
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DPS #7
DPS #7 is located on the Orleans Avenue Canal, 2.43 miles
from Lake Pontchartrain. Canals on the inlet side are
covered while the outfall canal is entirely open. The
Orleans Avenue Canal is leveed to protect the adjacent land
areas from flooding. DPS #7 is located in City Park and is
one of the oldest stations in the system. It was originally
constructed in 1895. Originally, it had been intended to
feed chlorine at DPS #7 rather than NaOCl in order to pro-
vide an evaluation of the two disinfection methods. However,
the feeding and storage of chlorine at DPS #1 was abandoned
due to safety considerations. Once the decision had been
made, storage and feeding facilities for NaOCl similar to
those at DPS #3, #4, and St. Charles were installed. The
NaOCl storage and feeding facility consists of two, 20,000
gal., polyethylene lined steel tanks for NaOCl storage and
two polypropylene lined disinfectant feed pumps. A flow
sheet of the sampling and feeding facilities is shown in
Figure 17.
ST. CHARLES PUMPING STATION
The NaOCl feeding facilities at the St. Charles pumping
station are unique. The discharge of this station is
located approximately 1,600 ft from Lake Pontchartrain.
The usual pattern of closed canals on the suction side of
the pumping station with open outfall canals on the discharge
canal has been reversed. Since this pumping station drains
an area which is presently being developed, drainage canals
leading to it have been designed as storage facilities for
storm water runoff prior to its being pumped. Since addi-
tional time was available to pump the storm water, the
station was built with less capacity than the pumping
stations in the older parts of town. Thus, a relatively
long period of time is available for contact between the
point of entry of the reaction basin. NaOCl is fed to
the storm water entering a reaction basin approximately
1,600 ft prior to pumping. This eliminates the problem in-
volved with chlorinated water being discharged to the lake
and its possible influence on the biota in the vicinity of
the discharge. To provide sufficient retention time for
complete reaction of NaOCl and storm water at different
rates of pumpage, it was necessary to provide a reaction
basin, measuring 1,673 ft by 98.5 ft by 11 ft, at the
station. A reaction basin of this size provided between
47
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7
1LJL
Tritcx
SODIUM HYPOCHLORITE Fg£f>W$ FACIUTY
TREATMENT ft SAMPLING FLOW
DIAGRAM - ORLEANS AV£. CANAL
FIGURE 17
DPS #7 FLOW SHEET NaOCl FEEDING FACILITIES
-------
22 and 86 minutes retention time based on the pumping rate
of the station. Soil conditions and the size of the
reaction basin required that it be completely lined with
concrete. NaOCl is fed under water at the inlet of the
reaction^basin as shown on the treatment and sampling flow
sheet (Fig. 18). For safety purposes, NaOCl storage and
feeding facilities are located at the station with NaOCl
being pumped to the point of application. One interesting
aspect of the reaction basin design was the inclusion of
relief holes in the bottom to equalize water pressure.
The relief holes eliminated the need for support and anchor
piling which would have been necessary to prevent the
reaction basin from rising out of the ground during drought
periods. A cross section of the reaction basin is shown in
Figure 19 along with a general plan view of the area. A
view from the St. Charles pumping station to the point of
disinfectant feed is shown in Figure 20.
The St. Charles DPS is equipped with four, 250 cfs pumps.
The NaOCl feeding facilities are similar to those at the
other pumping stations. Two, 20,000 gal. rubber lined
steel tanks store the NaOCl and two polypropylene lined
pumps are utilized to pump the disinfectant. Each poly-
propylene lined pump has a capacity of HO gal./min against
a 50 ft TDK.
RESIDUAL CHLORINE ANALYZERS
Each pumping station involved in the program utilizes a
residual chlorine analyzer (total available) to indicate
C12R levels for the purpose of controlling NaOCl feed
rate. The C1~R analyzers are amperometric analyzers
manufactured By Wallace and Tiernan. The C12R analyzers
sample water from the outfall canal just downstream from
the point of addition of NaOCl. The lag time to the point
of sampling by the C12R analyzer varies with the pumping
rate at the station. Therefore, it is not feasible to
attempt correlations with respect to retention time as had
been hoped. Contact time varied from two to 20 minutes.
The C12R is displayed on a four inch strip chart recorder
located on a control panel in the pumping station.
The C12R analyzers specifications stipulated that they
should be capable of continuous operation during the
treatment periods, which could last for days or weeks.
However, operation in this manner caused rapid failure
of the C12R analyzers and a continuous water supply from
-------
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SODIUM HYPOCHUORITE FEEOWO FACILITY
TREATMENT ft SAMPLING FLOW
DIAGRAM ST. CHARLES CANAL
FIGURE 18. ST. CHARLES DPS - FLOW SHEET NaOCl FEEDING FACILITIES
-------
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ST. CHARLES REACTION BASIN
PLAN a SECTION
FIGURE IB. CROSS SECTION OF ST. CHARLES REACTION BASIN
-------
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FIGURE 20. ST. CHARLES DPS - REACTION BASIN
-------
the main distribution system of the city to keep the cells
moist had to be provided at all times. This required the
use of inordinate amounts of reagent and buffer solutions.
It has been found that the solutions could be produced less
expensively by buying the basic ingredients in bulk and
producing the solutions on site. There also was plugging
of the buffer and potassium iodine pump and filters had to
be installed on the wastewater influent lines. On several
occasions, the feed lines for the buffer and potassium iodine
have split. There has also been corrosion on the solenoid
activated valve which controls the city water supply and
leaking of the gasket on the constant head device which
measures cell flow. However, when the Cl^R analyzers were
operational, good results were obtained. At present, there
does not seem to be any equipment in the C1~R analyzer field
which can be used intermittently on wastewater without major
modification. A picture of the Cl-R analyzers at DPS #7 is
shown in Figure 21.
FIGURE 21. DPS #7 - RESIDUAL CHLORINE ANALYZER
NaOCl FEED CONTROL SYSTEMS
Once the C12R is displayed at the control panel, the operator
can vary the NaOCl feed rate to regulate the dosage level
through the NaOCl feed control system. A NaOCl feed control
53
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facility consists of two pumps discharging NaOCl through a
common header, an electrically positioned control valve and
a magnetic flowmeter- The entire feeding facility is
operated from the control panel in the pumping station. The
control panel at St. Charles is shown in Figure 22. Each
control panel is equipped with three strip chart recorders,
a Salve positioner and switches for the pumps. The recorders
are four inch, electrically operated, strip chart recorders
manufactured by Fisher and Porter which continuously indicate
storm water temperature, rate of NaOCl feed and C12R. The
control valves are teflon lined butterfly valves equipped ^
with Ramcon electric valve actuators. The actuator is posi-
tioned by a signal set by the operator at the control panel.
The rate of disinfectant feed is adjusted manually by the
operator who attempts to maintain a pre-determined Cl.R
level in the treated water in the discharge bay of th§ station
during the period of pumping.
Flow of NaOCl is measured by a magnetic flowmeter. The
temperature sensing system consists of a temperature bulb,
capiliary tube, and signal transmitter. The Cl^R analyzer
is equipped with a signal converter and transmitter. The
output of each sensing instrument is converted to a 10 to
50 ma signal, transmitted to the control panel and recorded
on four inch strip chart recorders.
Little difficulty has been encountered with the piping at
the storage sites. One small pipe failure at St. Charles
was replaced by the manufacturer free of charge. The
polypropylene lined NaOCl pumps have been a continuing
source of difficulty. Due to the intermittent nature of
disinfection, NaOCl is allowed to remain in the pumps for
a protracted period of time. Thus, the problems encountered
with the NaOCl pumps at the feeding facilities are exactly
the same as those at the NaOCl manufacturing plant.
Little difficulty has been encountered with the Fisher £
Porter temperature units or Beckman DO probes. The Fisher
and Porter four inch strip chart recorders on the control
panels at DPS #3, #4, and St. Charles were a considerable
source of difficulty until surge resistors were installed.
EVALUATION PHASE SAMPLING FACILITIES
After the NaOCl had been fed to the storm water on a demand
basis, a means for evaluating the efficacy of the disinfec-
tant in reducing bacterial levels in the water had to be
-------
FIGURE 22. ST. CHARLES DPS - NaOCl CONTROL PANEL
55
-------
provided. It was not economically feasible to keep
personnel continuously on duty to take samples, and recourse
was made to automatic sampling techniques. Initially,
automatic analyzers were investigated. Howeyer, since the
primary purpose of the program was to investigate the effect
of the disinfectant on coliform bacteria levels, laboratory
work was required and a holding sampler was essential to the
project. The requirements of sampling were to take a pre-
determined number of discrete samples, at fixed intervals,
and keep them refrigerated until they could be analyzed.
The water samplers had to have the capacity to take a
representative sample of the storm water in the canals,
both before and after treatment with disinfectant. They
would also need to operate without attention during a
storm. Many commercial automatic samplers were investi-
gated, but none could meet the requirements of the project.
The sampler designed and built for this project is shown
in Figure 23. The samplers have the capacity to take 38
discrete samples and keep them refrigerated.
The sampler is activated by the station operator when storm
water is being treated with disinfectant. Once activated,
the sampler operates by opening and closing solenoid valves
at pre-determined intervals. On each opening, one sample
bottle is filled. Storm water is taken from the canal by
a positive displacement pump. The sampler pump operates
continuously during the sampling period. Thus, the water
being discharged into the sample bottle is representative
of the canal water and does not represent a mixture of
dead water which has been stored in the influent line, and
fresh water from the canal. The sample bottles are filled
to overflow with excess water going to waste. The sampler
pump and all parts were selected so that they would be
capable of passing the 0.25 inch solids which may be
present in the storm water although sampler inlet lines
were provided with screens to remove such particles.
The first automatic sampler was constructed and placed in
operation at DPS #3 in 1968, The prototype sampler used
copper tubing and fittings for all internal parts and
bronze solenoid valves. After several weeks of operation,
corrosion was noticed on the valve seats and the copper
tubing had discolored. After this experience, it was
decided to construct the automatic samplers utilizing PVC
or aluminum fittings. Thus, a redesign of the prototype
automatic sampler was required and the second and subsequent
samplers were constructed utilizing PVC pipe and fittings.
The configuration of the sampler remained basically the
56
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en
AltfOMATC **TEH
1WTERDR ARRAMCH0T
FIGURE 2-3. AUTOMATIC WATER SAMPLER - INTERIOR VIEW
-------
same.
The automatic samplers are located in the pumping stations
at DPS #3, and #4 and in portable metal buildings at DPS rr
and St. Charles Station. The metal buildings are the
knock down type, bolted construction and are skid mounted
to allow the location of sampling facilities to^be moved
(Fig. 24). This feature became very useful during the
post-construction evaluation when the downstream samplers
had to be moved from DPS #3 and #4 to DPS #7.
FIGURE 24. EXTERIOR VIEW OF METAL SAMPLER BUILDING
The samplers have worked as designed. There has been some
difficulty in keeping prime with the sampler pumps, but
this has been traced to air leaks or siphons in the suction
lines. The main difficulty at the sampling sites is
vandalism. The control wires from the pumping stations to
the sampler sheds, and the suction lines from the outfall
canals to the sampler sheds have been repeatedly cut and
damaged. The sample pump and electric controller from the
pre-treatment locations at St. Charles were stolen and
had to be replaced. Several bullet holes have also been
found in the sampler buildings at the St. Charles Station.
58
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SECTION IX
EVALUATION PROGRAM
GENERAL
To demonstrate the feasibility of reducing the coliform density
in polluted storm water pumpage by hypochlorination, three
distinct water sampling and evaluation programs were formulated.
The three programs were:
1. A five year base period evaluation which analyzed
data available from a five year period before the
program began.
2. A pre-construction evaluation program, lasting
22 months, during which the outfall canals
were sampled and analyzed for bacterial and
chemical pollution prior to the use of NaOCl.
3. A.post-construction evaluation program which
analyzed the effects of disinfection on the
storm water and the outfall canals.
The five year base period data extended from July 1, 1961 to
June 30, 1966. An analysis of this data provided the pre-
liminary design criteria for the NaOCl manufacturing and
feeding facilities' and gave an indication of the magnitude
of the bacterial pollution. The Pre-Construction Evaluation
Program, essentially a sanitary analysis, was begun March 1,
1967 and continued through December 30, 1968.
Chemical, physical and bacterial tests were run and the data
analyzed to determine the nature and magnitude of the pollution
present in the storm water, and to establish base line parameter
levels for the outfall canals. Upon completion of the dis-
infectant feeding facilities, a post-construction evaluation
program was carried out. This program demonstrated the
feasibility of reducing, by several orders of magnitude, the
indicator coliform density in bacterially polluted storm water
using large outfall canals in populated areas as disinfection
facilities.
59
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FIVE YEAR BASE PERIOD EVALUATION
GENERAL
The Five Year Base Period Evaluation x-?as carried out utilizing
data which had been gathered by the Sewerage and Water Board
of New Orleans, New Orleans Board of Health, and the Louisiana
State Board of Health from July 1, 1961 to June 30, 1966. This
data was used to:
1. Estimate the level of bacterial pollution in the
drainage canals.
2. To determine the quantity and frequency of storm
water pumpage.
3. Estimate the amount of NaOCl which would be
required to disinfect the water.
Sampling
Data records consisted of water samples taken from three out-
fall canals; Orleans, London, and Citrus, and from Lake Pont-
chartrain. The samples from the canals were analyzed for
total and fecal coliform densities. Bacterial densities were
derived by the Sewerage and Water Board using the membrane
filter technique, while both multiple tube and membrane filter
techniques were used by the New Orleans, and Louisiana Boards
of Health on Lake Pontchartrain samples. Bacterial densities
that were valid for more than one dilution for the membrane
filter technique were averaged on the basis of total volume
sampled. Storm water quantity and pumping rate data were
obtained from the log books of the pumping stations. Quantity
was determined by multiplying the capacity rating of the
pump by the time the pump held suction. Rainfall data were
taken from the rain gauges at the pumping stations.
Five Year Base Period Results
Data gathered during the five year sampling program were
plotted for visual inspection. The bacterial and physical
parameters from DPS #7 are shown in Figure 25. NO visual
correlations were evident. To further analyze the data,
coliform, water pumped, and rainfall values were punched on
60
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^ -
FIGURE 25. DPS #7 BACTERIAL 8 PHYSICAL PARAMETERS 5 YEAR BASE
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EVALUATION PROGRAM
-------
computer cards. Computer programs were developed to generate
intensity-frequency data for the anticipated use of NaOCl at
the drainage pumping stations. Design data for the planned
St. Charles station were developed from information available
from the Citrus station, which drains the same area. Inten-
sity-frequency data for water pumped on a one day and a five
day basis were developed. These data provided the basis for
estimating the quantities of NaOCl required during the project.
The rainfall pattern is essentially the same for_each station.
However, since each station has a different pumping capacity
and serves a different drainage area there are slight dif-
ferences in the water pumped data. The Orleans Avenue and
the London Avenue canal serve combined residential and indus-
trial areas with high runoff coefficients. The St. Charles
station serves a relatively undeveloped rural area with a
low runoff coefficient. The factor of different drainage
areas is also brought out in the total and fecal coliform
levels in the Orleans, London, and Citrus canals (Table 5).
The total coliform level in the Citrus canal is relatively
high, while the fecal coliform level is approximately the
same as the London canal. The Orleans Avenue canal was
higher in both types of bacteria.
The high total coliform level in the Citrus canal is partly
due to the almost constant pumping situation. If the canal
is allowed to remain fallow after a pumping sequence, there
is a tendency for the coliform levels to gradually drop as
the nutrients in the canals are used up and/or settle to the
bottom. The low fecal coliform levels in the Citrus canal
were probably due to the undeveloped nature of the area and
th« attendant low runoff coefficient •• Since there were few
hu;; an residents most fecal coliform pollution must have come
from the warm-blooded animal population (2), This population
includes domesticated animals as well as an abundance of
wildlife. In fact, this area was often frequented by hunters.
It should be noted that the Citrus station which served the
eastern portion of the city was replaced by the St. Charles
station in 1967. Thus, the data for the Five Year Base
Period are from the Citrus canal, while the Pre and Post-
Construction Evaluation data are from the St. Charles reaction
basin. It was felt that no substantial errors would be
introduced in the drainage water characteristics by this
change and the data from the two different stations are
considered to be characteristic of this drainage area.
The London Avenue canal has the lowest pumping frequency and
coliform level. This is due to the fact that'within limitations
62
-------
TABLE 5
BACTERIAL PERCENTILE LEVELS: 5 YR. BASE PERIOD
Total Coliform Fecal Coliform
25% 50% 75% 25% 50% 75%
London Avenue Canal 2,000 10,000 65,000 300 1,000 5,000
(DPS #3, 4)
Orleans Ave. Canal 4,000 18,000 130,000 400 1,000 7,000
(DPS #7)
Citrus Canal 1,000 5,000 110,000 400 2,000 5,200
(Citrus)
-------
governed by the capacity of the drainage system and the
location and intensity of the rainfall, DPS #3 pumps into
the Florida Avenue canal. Water from the Florida Avenue
canal is then repumped to Bayou Bienvenue or under extremely
light loading to the Mississippi River. Thus, the heavy
bacterial and chemical loading of the outfall canal during
the initial "flushing" of the system does not enter the
London Avenue canal. Since there are many routes drainage
water can take, a schematic of the possible flows^to and
from the pumping station in the project is shown in Figure 27.
The Orleans canal, which has the highest bacterial levels,
receives all storm water reaching DPS #7. However, this data
is influenced by the location of the sampling point which is
closer to the pumping station than on the London Avenue
canal. Thus storm water, with its high bacterial densities,
reaches the sampling point even at low pumpage rates and
before die off can occur. Also, the higher salinity levels
in the lake don't exert the same influence here. However, all
the canals were highly polluted bacteriologically as 90% of
all total coliform readings were above the limit of 1,000/100
ml recommended for body contact recreation waters by the
Louisiana State Board of Health.
Lake Pontchartrain data supplied by the Louisiana State
Board of Health indicated that the lake is more polluted
after pumping periods. However, the lack of a systematic
testing program to eliminate other sources of pollution pre-
clude assigning the increased bacterial levels entirely to
storm water pumpage.
The intensity-frequency data developed for rainfall and water
pumped at DPS #7 (Table 6) demonstrate the quantities of water
involved. From the data, it is evident that some rainfall
can be expected on approximately one day out of every three,
and that one inch or greater rainfall can be expected approxi-
mately fifteen days per year. However, even though most
pumping stations are equipped with an automatic rain gauge,
the operating characteristics of the drainage system prevent
obtaining any valid correlation between quantity of rainfall
and quantity of water pumped into the outfall canals. In
developing intensity-frequency data for water pumped at DPS
#3, and #4, only that water pumped into the London Avenue
canal was considered.
The data indicated that water was pumped on approximately
20% of the days which is somewhat less than the rainfall
frequency since not every rainfall results in pumpage. Also,
when pumpage occurred, it exceeded 20,000,OOOcfd on"30%
of the days. When data from hurricane periods and other
-------
CD
cn
TABLE 6
RAINFALL £ WATER PUMPED FREQUENCIES
% of Days
RAINFALL
RAINFALL >1.0 in.
DPS 7
DPS 3
DPS 4
Citrus
Base
DPS 7
DPS 3
DPS 4
Citrus
DPS
Base Period
27,0
27.5
30.0
DPS 31.5
WATER PUMPED
Pre-Const
27.0
32.0
29.0
29.0
WATER
Period Pre-Const Base
45.0
14.0
11.5
87.5
39.0 6
53.0 7
9.5 3
69.5 ' 22
PUMPED
Period
.0
.5
.5
.5
Base
>5xl06cfd
Pre-Const
11.0
8.5
2.5
12.5
5.0
5.0
5.0
6.5
id Pre-Const
4.0
3.5
4.0
3.5
WATER PUMPED >10xlQ6cfd
Base Period Pre-Const
4.0
3.5
2.0
11.5
6.5
4.5
1.5
5.0
-------
LAKE PONTCHARTRAIN
en
ORLEANS AVE. CANAL >.
V /
_i
<
<
o
ui
£
O
Q
_J
\
x-
V
VHV
DPS/7 DPS^3
/
\ /
^
«. _. x* " •*%,
/' N\ c
nno Jfjt 1 NFW RF4? 1
DPS#4 1 INLW Kt-0. j
v y
VLV /
/ NE
< ' r n '
1 FLORIDA AVE. 1 V a
LV ^ ^ 1 CANAL TO 1 \
•> ' 1 BAYOU 1 V
j BIENVINUE J
/\
ST.
HARLES
REACTION
J__|BASIN
iW RES. \
UNDEV. 1
/
OLD RES
SEMI-
A
\^c.mi - .
COMM- /
OLD RES. \
a )
DOWNTOWN J
X
HV= HIGH VOLUME PUMPAGES
LV= LOW VOLUME PUMPAGES
DPS= DISCHARGE PUMPING STATION
RES= RESIDENTIAL
UNDEV= UNDEVELOPED
FIGURE 26. SCHEMATIC DIAGRAM OF DRAINAGE SYSTEM INVOLVED IN PROJECT
-------
extraordinary rainfalls were removed from consideration, it
was found that treatment facilities for average water pump-
ages of 79,277,000 cfd or 529,990,000 gpd would be needed"
for three pumping stations originally scheduled to use
NaOCl, and 27,600,000 cfd or 204,210,000 gpd at DPS #7,
originally scheduled to use Cl . The total quantity of
storm water requiring treatment was 106,877,000 cfd or
734,230,000 gpd. DPS #7 was subsequently converted to NaOCl
in the interest of safety.
Five day periods were considered in planning disinfectant and
transportation requirements. The data indicated that NaOCl
treatment facilities would be required for 277,258,000 cf
(2,193,890,000 gal.) of storm water in five days which was
slightly more than five average day pumpages.
PRE-CONSTRUCTION EVALUATION PROGRAM
General
The 22 month Pre-Construction Evaluation Program which fol-
lowed the Five Year Base Period Evaluation was basically a
sanitary water analysis program. The objectives of this
program were:
1. To establish a baseline of total and fecal
coliform levels in storm water discharged to
the outfall canals.
2. To determine the overall quality of the storm
water discharged and the quality of the water
in the outfall canals between pumping periods.
3. To determine an empirical relationship between
coliform levels and one or more easily deter-
minable parameters.
Sampling Program
The Pre-Construction Evaluation Program consisted of recording
rainfall data from gauges at the pumping stations, water pump-
age data from the pumping station log books, and taking grab
samples from the pumping station suction bays and outfall
canals for bacteriological and chemical analysis. _The grab
samples were taken every Monday, Wednesday, and Friday from
pre-selected points on the Orleans, London and Citrus canals,
67
-------
the suction bays of DPS #4, and #7, and once a week, weather
permitting, in Lake Pontchartrain. The water samples were
all taken at a depth of approximately 24 in. The sampling
locations in the canals were approximately the same for the
pre-construction program as for the five year base period
to provide continuity- The sampling points are shown in
Figure 27.
The grab samples from the stations and outfall canals were
analyzed for the following parameters:
Total coliform BOD
Fecal coliform Suspended solids
Enterococci pH
COD Chlorine demand
DO Temperature
All samples were analyzed in accordance with the procedures
found in Standard Methods for the Examination of Water and
Wastewater, l2th Edition. ~ ~ " ' ~
As in the Five Year Base Period Evaluation, extensive data
were collected. The weekly sampling and pumping data combined
to give over 25,000 items of data. In order to manipulate
such a mass of data, a computer again had to be utilized.
The computer facilities used during the Five Year Base Period
Evaluation were not available during the pre-construction
program and a time-sharing computer facility was utilized.
The initial step taken in the analysis was to compile, tabulate
and plot the data. The data was plotted by sampling location
and representative curves for coliform and physical parameters
at DPS #7 are shown in Figure 28. Three curves were required
for each sampling location to provide sufficient resolution
of the parameters. Water pumped was plotted on each of the
curves because it is the parameter which indicates the
existence of a new set of initial conditions.
The data curves indicate the overall quality and quantity of
the water to be treated. The parameters were statistically
analyzed to provide quantitative measures of the water quality.
Also, an effort was made to obtain a correlation between one
or more of the parameters susceptible to continuous monitoring
and the total coliform density. Thus, a method which would
give a quick indication of the coliform level would be avail-
able. Four parameters were chosen for extensive study; total
coliform, suspended solids, temperature, and dissolved oxygen.
Total coliform was chosen because the reduction of this para-
meter was the prime concern of this project. The other three
68
-------
ov
to
& LAKE SAMPLING POINTS (100 Fl. Offthort)
O PUMPING STATIONS
A CANAL SAMPLING POINTS
FIGURE 27.. PRE-CONSTRUCTION EVALUATION PROJECT SAMPLING POINTS
-------
FIGURE 28. DPS #7 - PRE-CONSTRUCTION EVALUATION PROGRAM -
BACTERIAL, RAINFALL & WATER PUMPED DATA
-------
parameters were chosen because they could all be quickly
measured and continuously monitored by automatic analyzers.
If a correlation was found, the incoming bacterial density
could then be calculated using the correlation equation.
The bacterial density desired in the effluent would then be
used to calculate the degree of reduction required. Once
the degree of reduction was known, the dosage of NaOCl above
that required to satisfy the chlorine demand would be known.
The values for these parameters were placed on punch cards
and statistical tests were performed. Typical frequency
histograms for the four parameters were all skewed to the
right as can be seen in Figures 29 through 32. Dissolved
oxygen, suspended solids, and temperature distributions were
fairly continuous but did not appear to have a gaussian
distribution. The total coliform data tended to be very dis-
crete and no conclusion could be made as to the distribution.
When total coliform readings were grouped to include only
values on days water was pumped, they were found to be nor-
mally distributed. However, this was revealed to be more a
function of the sampling procedure than a property of the
data. The samples that were recorded on pumping days could
have been taken before, during, or after a pumping period.
Since the coliform levels depend on the time the sample was
taken, it is not surprising that the data were normally
distributed. No log transformation or chi square tests were
performed, but when the data were plotted on a log basis,
it did plot normally. Since the other parameters did not
appear to display any of the standard distributions, further
statistical distribution tests were abandoned.
Several curves were drawn using the four parameters as in-
dependent and dependent variables. At first, it seemed that
some periodic relations existed between total coliform, dis-
solved oxygen, and suspended solids when temperature was
held constant. Upon further analysis this was not found to
be the case.
A second approach would have separated the data into various
concentration levels for each parameter. Then using one
parameter as the dependent variable, the levels of two other
parameters are chosen as independent variables and used in
composing factorial arrangements. These factorial arrange-
ments could then be subjected to an analysis of variance.
Those main effects and interactions between constituents
which tested as significant in the analysis of variance would
be included in a multiple, non-linear regression analysis
utilizing all the data for the significant parameters. It
was felt that this procedure would provide either one or a
series of equations from which the necessary quantity of
71
-------
o
Z
Ul
o
UJ
(M [O
2 8
TOTAL COLIFORM xlO6 org/IOOml.
HISTOGRAM
TOWL COLIFORM-0-Z5,OOO,000
ORLEANS AVE. CAMAL
FIGURE 29. ORLEANS AVENUE CANAL (DPS #7) PRE-CONSTRUCTION EVALUATION
PROGRAM ,- TOTAL COLIFORM HISTOGRAM
-------
s 8 2 8 - B
V
SUSPENDED SOLIDS Mg/L
a i § s
HISTOGRAM
SUSPENDED SOUOS
ORLEANS AVE. CANAL
FIGURE 30. ORLEANS AVE. CANAL (DPS #7t-FRE-CONSTRUCT10N EVALUATION PROGRAM
SUSPENDED SOLIDS HISTOGRAM
-------
i s
DISSOLVED OXYGEN Mg/L.
HISTOGRAM
DISSOLVED OXYGEN
ORLEANS AVE, CANAL
FIGURE 31. ORLEANS AVE. CANAL (DPS # 7) PRE-CONSTRUCTION EVALUATION PROGRAM
DISSOLVED OXYGEN HISTOGRAM
-------
io r
! I
§
7 _
5 —
cvj 04
"X"
TEMPERATURE
n
oi
HISTOGRAM
TEMPERATURE «C
ORLEANS AVE. CANAL
FIGURE 32. ORLEANS AVE. CANAL (DPS #7) PRE-CONSTRUCTION EVALUATION PROGRAM
TEMPERATURE HISTOGRAM
-------
NaOCl required to obtain specific residual chlorine levels
on the discharge side of the pumping station could be deter-
mined.
Analysis of Variance
The general, linear, analysis of variance model (co- variance
if more than one independent variable is involved) has the
form ( 3 )
where Y is the dependent variable, x and z are independent
variables, a and g are effect coefficients of the indepen-
dent variables, and e is the experimental error. Invariance
of the effect coefficients of the independent variables, one
of the prime assumptions of this model cannot be met when
considering data taken during the Pre-Construction Evaluation
Program because the drainage system has time, temperature,
spatial and concentration dependencies.
Time dependency is found on Several levels and contains both
trends and stochastic series. First, the characteristics of
the entire drainage area are changing with time. This can
be seen in Table 7 where the total coliform and fecal coliform
levels for the five year base period are compared with data
from the Pre-Construction Evaluation Program. This increase
of levels with time is self-evident. Also, the means of the
various parameters vary with months as shown in Figures 33
through 36 and, thereby, display a seasonal effect. Third,
the length of time between pumping periods also effects the
data and, by virtue of its dependency on rainfall, is
stochastic.
The effects of the diurnal cycle, temperature, space, and
concentration are well documented in the literature. No
attempt will be made to review this aspect of the changing
character of the drainage system.
In an effort to remove several of the time and temperature
effects, a program to structure the data by day after pumping
was written and run. The results were then subgrouped by
level as shown in Figure 37 for DPS #7. As expected, tem-
perature and season were related. The phenomenon of total
and fecal coliform die off with time was also noted. This
die off arises from their exposure to the relatively harsh
biological environment. BOD and COD values did show a
76
-------
TABLE 7
BACTERIAL PERCENTAGE LEVELS: 5 YR BASE PERIOD vs PRE-CONSTRUCTION EVALUATION
TOTAL COLIFORM
London Ave Canal
(DPS #3, 4)
Orleans Ave Canal
(DPS #7)
Citrus - St Chas. 1000
London Ave Canal
(DPS #3, 4)
Orleans Ave Canal
(DPS #7)
Citrus - St Chas.
25%
000
000
000
25%
300
400
400
5 YR
50%
10,000
18,000
5,000
5 YR
50%
1,000
1,000
2,000
PRE-CONSTRUCTION
75%
65,000
130,000
110,000
FECAL COLIFORM
75%
5,000
7,000
5,200
25%
16,000
105,000
19,000
25%
650
5,500
900
50%
80,000
1,050,000 6,
3,000
PRE-CONSTRUCTION
50%
4,900
75%
470,00
000,00
250, oa
75%
2i,ooa
40,000 250,000
5,000
20 ,000
-------
E
o
o
f
(E
o
o
o
o
DATf
LEGEND
MABCH 67 TO NOV. 68
A STATION 3
A STATION 4
O STATION 7
TOTAL COLIFORM
ARITHMETIC MEAN VS. TIME
D.P.S. NO. 3,4,7 DISCHARGE
FIGURE 33. PRE-CONSTRUCTION EVALUATION PROGRAM - TOTAL COLIFORM -
ARITHMETIC MEAN vs TIME DPS #3, U, 7 DISCHARGE
-------
D&TE
LEGEND
MARCH'67 TO NOV. 68
4 STATION 3
A STATION 4
O STATI ON 7
SUSPENDED SOLIDS
ARITHMETIC MEAN VS. TIMC
0-R3. NO. 3,4,7 DISC HARSE
FIGURE 34. p RE-CONSTRUCTION
PROGRAM SUS-PENBE-g-'
ARITHMETIC MEAN vs TIME DPS #3, 4, 7 DISCHARGE
-------
DATE
LEGEND
MARCH 67 TO NOV. 66
A STATION S
A STATION 4
O STATION 7
DISSOLVED OXYGEN
ARITHMETIC MEAN VS. TIME
D.P.S. NO 3,4,7 DISCHARGE
FIGURE 35. PRE-CONSTRUCTION EVALUATION"PROGRAM - DISSOLVED OXYGEN - ARITHMETIC
MEAN vs. TIME DPS #3, 4, 7 DISCHARGE
-------
CO
DATE
LEGEND
MARCH 67 TO
A STATION 3
A STA..TJON 4
O STATION 7
NOV. 68
TEMPERTURE C*
ARITHMETIC MEAN VS. TIME
P.P.S. NO. 2,4,7 DISCHARGE
FIGURE 36.
EVALUATION PROGRAM
- TEMPERATURE - ARITHMETIC
vs. TIME DPS #3, 4, 7 DISCHARGE
-------
% TC FC E R
K>0
H 5°
U 50
M so
U 50
I
1
1 .
1 ill I
1
II II, 1 .1, . ll
I i 1 JLl J 1 1 L _^\ I
. . . 1 1 1 . I 1 1 III III
P 2 3 3T P I 2 3 3" P I 2 3 3* PiZ
0
H X°6
U io5-io6
M »4-io5
4
L W5 (55) >*} (1) >OO (28) >3«K>7 (5) >27 (67) >6.0 (13) >90 (II) >7.5 (32) >30 (9) >4X) 69) >K» (6)
(42) lo'-IO1 (45) IO4-I05 (12) JO-CO (108) C7-3»I07 (35) 23-27 (53) 7.6-aO (33) 30-50 (38) 5.0-75 (36) 2O-30 (17) 3.3-4.0 (25) 60-100(21)
(21) I03-!0' (24) B'-O" (18) .05-JO (16) lcf-C7 (147) 19-23 (22) 7.2-7.6 (49) O-3O (103) 2.5-5.0(56) »-20 (43) 2.0-33 (97) 30-60 (14)
(17) <»" (19) 6 (77)
-------
reduction in time, if values were followed in days after
pumping, due to the normal satisfaction of these damands,
There were no other correlations evident.
After all groupings had been made, no analysis of variance
could be run because none of the groupings of data had a
sufficient number of readings to fill" a factorial arrangement.
This was evident during the attempt to correlate total coli-
form with dissolved oxygen, suspended solids, and temperature.
when two time factors, diurnal and seasonal,-variation*, are
included in a four level factorial design 4 or 1024 data
sets would be required if a controlled experiment is to be
r^n. Even a simple two level factorial design would require
2 or 64 data sets. A sorting program provided approximately
60 data sets per pumping station which included at least
three of the variables. Unfortunately, even with these sets
there were many replications and omissions due to the random
nature of the pumping and the variables. Thus, even a two-
level factorial arrangement cannot be carried out for the
four parameters involved. After consideration of the data
by day and level it was decided not to run the variables as
simple factors since no correlation other than those already
noted would be found.
The lack of ordered values was caused by the stochastic nature
of the initial conditions of the parameters in the suction
bay of the pumping station. The initial conditions are
stochastic due to the dependency on rainfall and to the
continually changing characteristics of the drainage area.
Besides causing the lack of data points in the subgroups,
this means that the system being sampled is itself in con-
stant change. Hence, it was felt that an analysis of
variance was not indicated for finding relationships between
and among the parameters of the Pre-Construction Evaluation
Program.
Ultimately, the main obstacle encountered in all attempts of
analysis of the data was the stochastic nature of the drain-
age system. The fact that this was not recognized when the
initial data sampling programs were formulated resulted in
the collection of a great deal of data which had limited
value and was useful only to provide base line level of
parameters for the Post-Construction Program.
Pre-Construction Evaluation Results
The object of the Pre-Constructioh Evaluation Program was to
provide a characterization of the quality of the pumped storm
83
-------
water, outfall canal water, and lake water. This was accom-
plished. However, attempts to deterministically establish
relationships between total coliform and other parameters
that could be used in controlling the application of disin-
fectant in the Post-Construction Program were not successful..
The analysis of the data was begun by compiling, tabulating,
and plotting the data. From the plots of the data, several
immediate observations were possible. The coliform levels
were very high in each outfall canal with a large percentage
of the total coliform readings above 1000 org/100 ml. Even
more polluted, bacterially, were the suction bays at the
pumping stations. Also, the fecal coliform readings seemed
to stay in constant proportion to the total coliform readings.
Concurrently, other parameters traditionally used in indica-
ting pollution were at very low values. However, the values
represent standing as well as pumped water and thus were
expected to be lower.
To give a more quantitative measure to these observations,
computer programs to calculate intensity-frequency data,
means, and standard deviations were written and run. The
means and standard deviations of the chemical and physical
parameters are given in Table 8.
It was found that the bacteriological pollution was great
with 99% of the total coliform readings on the suction side
of the pumping stations and 92.8% of the total coliform
readings in the outfall canals exceeding a level of 1000 org/
100 ml. The water in the suction bays was more bacterially
polluted than in the corresponding outfall canal where
dilution by lake water takes place. The magnitude of the
bacterial pollution is also indicated in Table 7. (pg. 76)
The relationship between total coliform and fecal coliform
levels was of interest since the five year base period data
had demonstrated the possibility of a ten to one relation-
ship between the two parameters. A program to calculate the
ratio of total and fecal coliform produced a mean value with
a standard deviation of 47,2. However, after re-evaluating
the curves, a correlation was sought between the character-
istics of the^log10 transformation of the total and fecal
coliform readings. This was successful with correlations for
each station being in the 99% or better confidence band.
These correlation coefficients are given in Table 9. This
fact was useful in planning the laboratory analysis since it
indicated that the fecal coliform levels were one order of
magnitude less than the total coliform levels. Also, the
Five Year Base Period Evaluation had indicated that the nature
-------
TABLE 8
MEANS 6 STANDARD DEVIATIONS
PRE-CONSTRUCTION EVALUATION DATA
22 MONTH ANALYSIS
3D
4S
4D
7S
CD
Cn
WATER PUMPED - cfd
Weight~~~
Mean [ft: ]
Std. Dev.
RAINFALL - in.
Mean
Std. Dev.
BOD - mg/1
Mean
Std. Dev.
COD - mg/1
Mean
Std. Dev.
DO - mg/1
Mean
Std. Dev.
Cl DEMAND-mg/1
Hean
Std. Dev.
•"IB
lean
Std. Dev.
SUSPENDED SOLIDS - mg/1
Hean
Std. Dev.
TEMPERATURE - °C
Mean
Std. Dev.
82,953,592,799
3,682,505
7,154,522
8:81
8.3
6.6
72.9
62.9
4.3
2.4
3.3
1.4
7.3
0.4
25.6
23.7
25.1
4.9
6.7
4.9
56.3
37.9
4.3
4.0
3.4
0.9
7.7
0.4
27.4
22.8
26.6
5.1
18,456,172,800
5,377,672
6,122,526
0.53
0.67
7.9
6.8
81.3
60.1
5.4
2.0
3.5
1.4
7.6
0.4
27.1
37.0
24.9
5.2
15.2
11.3
76.3
48.9
2.8
1.8
3.3
1.1
7.6
0.3
35.5
36.6
24.8
5.0
7D
83,754,444,694
5,084,161
7,785,217
0.52
0.70
11.7
8.7
68.3
44.8
4.5
3.1
3.5
2.4
25.8
26.4
25.6
4.6
IPS
87,380,336,158
3,111,835
3,579,620
0.50
0.71
9.6
6.5
80.0
44.4
5.2
2.1
3.6
1.5
7.6
0.3
51.3
32-.2
24.3
5.8
-------
of the bacterial pollution was different in the Citrus canal.
However, as the area changed from-a rural to a developed
region, the coliform levels increased and the ratio, total
to fecal, approximated that in older developed regions.
The visual observation of very low levels for non-bacterial
parameters were corroborated. As an example, the suction^
bay at DPS #7 has the highest level of bacterial and chemical
pollution of any pumping station. However, BOD, COD, and
suspended solids levels were all seen to be relatively low.
Only one BOD reading in 171 samples was > 50 mg/1, one COD
reading in 43 samples was > 175 mg/1, and nine suspended
solids readings in 185 samples were > 100 mg/1. The levels
varied from station to station, but all were very low.
Several other parameters were also studied. pH levels varied
with 90% of the readings between 7.2 and 8.0. Dissolved
oxygen data indicated that 93% of the readings were above
2 mg/1. From the temperature intensity-frequency curves, it
was noted that approximately 75% of the readings were taken
when the temperature was above 25%C.
POST-CONSTRUCTION EVALUATION PROGRAM
General
Following completion of construction, a sampling program was
carried out to study the effectiveness and determine the
cost of coliform reduction by hypochlorination. The post-
construction evaluation phase continued the weekly canal
sampling program of the pre-construction program. Lake
samples were only taken after storms. Additionally, numerous
water samples were taken during low and high volume pumping
operations while NaOCl was being added to the water. These
programs were known as, Routine (canal and lake), Storm and
Storm Profile Sampling, respectively.
The methodology and sampling points to be used in these three
programs were chosen at the beginning of the project. However^
from an analysis of the pre-construction data and the method
of operation of the pumps at the pumping stations, it became
apparent that the sampling programs originally contemplated
for the Post-Construction Evaluation Program could not be used
to accomplish the goals of the project. In particular, the
post-treatment samplers located at DPS #3, #H, and #1 were
up to 10,000 ft from the point of discharge of treated storm
water into the outfall canals. Thus, they were too far removed
86
-------
TABLE 9
COLIFORM CORRELATION COEFFICIENTS
r CTCrFD]
D.F.
r*
r [TC:E]
D.F.
r*
DPS
3S
.856
161
.200
.695
79
.284
DPS
4S
.612
158
.208
.419
88
.269
DPS
4D
.742
159
.208
.625
83
.278
DPS
7S
,635
157
.208
.508
82
.280
DPS
7D
.821
142
.210
.594
76
.291
Citrus
DPS-S
.659
147
.209
.279
86
.273
Characteristic Clog10 FC] = a Characteristic [log,Q TC] + 8
Characteristic Clog10 E] = a Characteristic [log1Q TC] + 6
r = Correlation coefficient
r* = Correlation coefficient required
for 99% confidence
D.F. = Degrees of Freedom
S - Suction Bay
D - Discharge Bay
87
-------
from the site of treatment. Due to transport delay, diffusion,
and dispersion, treated water from the pumping station would
pass the downstream sampler at an unknown time. Also, during
low and moderate pumping rate operations, no treated water
would ever arrive at the downstream sampler at an unknown time.
Also, during low and moderate pumping rate operations, no
treated water would ever arrive at the downstream sampler
during the period of disinfection. To alleviate this problem,
the downstream samplers from DPS #3 and #4 were moved to DPS
#7 and located so that any mode of operation at the pumping
station would cause water to be sampled at least once at a
downstream sampler location. The result of these changes
was the location of a complete storm profile facility at
DPS #7 with a secondary site at the St. Charles pumping sta-
tion. Only storm operation and routine data were taken at
DPS #3 and DPS #4.
The results of the routine sampling program demonstrated that
the overall chemical and physical characteristics of the
water in the outfall canals had not substantially changed
since the 22 month Pre-Construction Evaluation Program. How-
ever, the long term fecal coliform levels at the pumping
stations had decreased due to the feeding of NaOCl. The
storm profiles run at DPS #7 showed conclusively that it was
possible to reduce the total and fecal coliform densities
to extremely low levels, less than 10 org/100 ml, for short
periods of time in the outfall canals. However, once treat-
ment had ceased, total coliform densities quickly recovered
to those levels present in the outfall canals prior to pump-
ing and disinfection. Fecal coliform densities also recov-
ered but to a lesser degree. Basic microbiological theory ''
indicated that the subsequent regrowth of indicator coliform
is an expected phenomenon. However, it should be noted
that the important effect of decreasing the total number of
human specific pathogens in the water should have been pro-
vided by disinfection. If this is the case, the human
specific pathogen levels in the treated raw storm water
would have been greatly reduced and it could be assumed that
the relatively harsh environmental conditions in the outfall
canals preclude regrowth of the pathogens to a dangerous
level. This is a point that requires further study even
though it appears to be the reason for diminished fecal
coliform regrowth in aftergrowth studies and lower long term
coliform levels in the outfall canals. Also, it is important
to note that the significance of the indicator coliform group
levels is radically altered once disinfection has occurred.
After disinfection their presence no longer provides the
same measure of possible pathogenicity of the treated storm
water.
88
-------
Sampling Programs
Routine Sampling
Routine sampling took place in the outfall canals on Monday,
Wednesday, and Friday morning of each week. , Samplers in the
outfall canals at DPS #7 and St. Charles were operated and
took five samples. The samples were composited and bacterial
and chemical values were derived. Grab samples were taken
at DPS #3 and #U. Values were found for the following
parameters :
Total coliform Chlorine demand
Fecal coliform Nitrogen (ammonia)
DO Salinity
Total suspended matter Chemical oxygen demand
pH
Data taken during routine sampling was analyzed and compared
with the results of the 22 month Pre-Construction Evaluation
Program. Specific areas of interest were changes in para-
meter levels which could be attributed to disinfection as
well as changes in the characteristics of the drainage area.
Storm Sampling
Storm sampling during NaOCl feed and low pumpage rates was
carried out at DPS #3, #4 and #7 and St* Charles. A low level
pumpage period was defined as any storm pumping which con-
sisted of a pumpage rate less than 500 cfs for a period of
thirty minutes. The purpose of the storm sampling program
was to characterize the storm water during the initial phases
of storm water pumpage. By characterizing the storm water
during the period of treatment, the storm profile results
from DPS #7 could be utilized at DPS #3 and #<4 in order to
treat the water in an optimum manner- During storm operations,
samples were taken at each rate of pumping and composited
to provide samples for analysis. Samples were analyzed for:
Total coliform Chlorine demand
Fecal coliform pH
Salinity Total suspended matter
Temperature Total solids
Nitrogen (ammonia) Volatile suspended matter
COD BOD
Enterococci
89
-------
Once the immediate bacterial, chemical, and physical para-
meters were determined, a 100 ml sample was stored at 20°C
to determine aftergrowth of coliform and enterococci. Lake
samples were taken from the shore as soon as possible after
cessation of the storm.
Data from the storm sampling program was compared with the
influent characteristics of storm profiles at DPS HI as well
as the data available from the Pre-Construction Evaluation
Program,
Storm Profile Sampling
A storm profile consisted of numerous samples taken during
the period of NaOCl feed and high volume pumpage operation.
A high volume pumpage operation was defined as greater than
500 cfs for one-half hour at the pumping station.
Sixteen storm profile samples were taken at DPS #7. It was
also hoped that storm profiles could be taken at the St.
Charles pumping station. However, the unmanned operation of
the station, extensive equipment failure, and vandalism at
the St. Charles station (pg58) resulted in a complete lack
of storm profile data from the St. Charles station. One
preliminary profile had been taken in 1970, but the data
collected was not in the format of the storm profiles taken
during the Post-Construction Evaluation Program.
Four sampJers, A, B, C, and D were in operation during the
disinfection and pumping operation at DPS #7. Samples were
taken (1) at four minute intervals at A in the suction bay
and at B in the discharge bay immediately downstream of the
station; (2) at 15 minute intervals at C, 0.25 miles down-
stream; and (3) at 30 minute intervals at Ds 1.50 miles
downstream. The location of the sampling points is shown
in Figure 38. As previously noted, no storm profiles were
taken at DPS #3, #4, or St. Charles.
Storm profile samples were analyzed for the following para-
meters :
Total coliform Nitrogen (ammonia)
Fecal coliform Salinity
pH Total suspended matter
Temperature
The bacterial and chemical results for A and B were derived
by compositing samples while C and D results are discreet
values. The compositing at A and B was carried out in the
90
-------
(6
, LAKE SAMPLING POINTS (ON SHORE)
PUMPING STATIC'-S
, CANAL SAMPLING POINTS
FIGURE 38. POST-CONSTRUCTION EVALUATION PROGRAM - STORM WATER SAMPLING POINTS
-------
following manner. For the first 32 minutes, samples were
composited with a maximum of two samples per composite sample
so that the rapidly changing characteristics of the water
during the initial stages of disinfection would not be
obscured. Thereafter, a maximum of seven samples were used
per composite. The composite value was plotted at a
mean time determined by averaging the sampling times of the
individual samples. As an example, samples 1 and 2 at A
would be composited and plotted at t = 6 min, samples 9
ghrough 16 would be composited and plotted at t = 45 min,
Chlorine residual and NaOCl feed rate values were taken
from the four inch strip chart recordings on the control panel.
Water pumpage data were taken from the pumping records at the
pumping station. Values for total suspended matter were derived
for initial and final samples only.
The magnitude of the amount of water treated and representa-
tive results for the sixteen storm profiles are given in
Table 10. As can be seen, <10m.32xl06 gallons of water
were treated with greater than 35x103 gallons of NaOCl. The
operating characteristics of the pumping station prevented
all water from being treated on certain occasions. Since
the top priority of the stations is to prevent flooding,
the operation would begin pumping prior to notifying the
treatment and sampling personnel. Thus, large quantities of
water would be pumoed before treatment began. Because of
this fact, the largest single treatment episode was not on
May 12, 1972, but July 20, when 68.19xl06 gal. of storm
water was treated with 8143 gal. of NaOCl. Excellent maximum
coliform removals were attained with average chlorine
residuals of 0.19 mg/1 to 0.82 mg/1. Average chlorine
residuals were calculated by taking the time average of the
chart recording. The maximum removal rates were calculated
by using the average input coliform reading at sampler A
and the minimum coliform value at either sampler B or C,
whichever was lower. When samples from A were not available
due to sampler intake heads breaking, prime point B was
used as the input parameter. Coliform removal rates improved
at the end of the project due to two factors. One was the
apparent familiarity of operators with the response of
the system, especially with respect to the time lags
inherent in the feedback loops. Secondly, it was found
that a period of prechlorination prior to initiation of pumping
alleviated the original "slug" of high coliform levels (pg.114).
92.
-------
TABLE 10
POST CONSTRUCTION STORM WATER TREATMENT EPISODES
Storm Water
Treated
Date [galxlO6]
Dec. 7, 1971
Feb. 7, 1972
Mar. 2, 1972
Mar. 9, 1972
Mar. 19, 1972
May 11, 1972
May 12, 1972
June 9, 1972
July 5, 1972
July 12, 1972
to July 13, 1972
40 July 20, 1972
Sept. 30, 1972
Oct. 22, 1972
Nov. 4, 1972
49.4
17.07
67.96
36.15
59.81
58.23
312. 651
17.29
146. 711
39.30
61.98
68.19
If. 82
76.72
15.04
NaOCl
Used [gal]
__
I'.Sl
—
—
644
1327
3919
1197
3727
2592
2681
8143
2346
6788
854
NaOCl Strength
[gram/1]
86.5
64.3
76.6
75.2
76.6
62.4
62.4
57.4
60.9
49.6
49.6
47.5
58.9
53.2
51.8
Avg. C1R
[mg/1]
__
.55
—
—
—
.23
.31
.19
.32
.27
.82
.78
.49
.42
Max. Total
Co li form Removal
Rate [%]
__
99.96
99.84
99.99
99.99
99.65
*
*
99.98
99.9
99.99
99.9998
99.9998
99.997
99.99999
Max. Fecal
Coliform Removal
Rate [t]
__
99.9
99.99
99.8
99.99
99.95
*
*
99.9
99.9
99.99
99.998
—
99.998
99.999
Total
1041.32
>35,699.
* MINIMUM VALUE NOT AVAILABLE
1 ALL STORM WATER NOT TREATED
-------
The data taken at DPS #7 showed that it was possible to reduce
the total colifor level in the outfall canal below 1000 org/
100 ml as required by the Louisiana State Board of Health.
Decreases in fecal coliform levels were commensurate with total
coliform level changes. However recovery of both groups of
indicator organisms occurred within 24 to 30 hours.
Post-Construction Evaluation Results
Routine Sampling
Routine samples were taken three times a week in the outfall
canals at the four pumping stations involved in the project.
Values attained were placed on punch cards and statistically
analyzed. The chemical and physical results for the Orleans
Ave. canal (DPS #7) are shown in Table 11. As can be seen, the
average values for the chemical and physical parameters during
the Post-Construction Evaluation Program were comparable to
those found during the Pre-Construction Evaluation Program.
Salinity and nitrogen (ammonia) values were not taken during the
pre-construction program. However, it can be seen that the
water is predominately fresh water although there are some
dissolved minerals present. The average temperature in the
outfall canals for the two programs was almost the same with
no significant difference. Nitrogen (ammonia) is seen to be
present at a very low level. COD levels did not vary aopreciably
between the two sampling programs, and neither have Cl^D, pH,
DO, or total suspended matter levels. This indicates 4hat the
basic chemical and physical nature of the storm water in the
Orleans Avenue Canal (DPS #7) did not change.
The only parameters which have changed during the Post-Construction
Evaluation Program are the levels of total and fecal coliforms
(Figures 39 to 44-). As can be seen, the level of fecal
coliform has dropped to less than that present during the
Five Year Base Period in each outfall canal. This is to be
expected from the treatment of the polluted storm water as
fecal coliform organisms do not regrow to the same extent as
total coliform. Also, total coliform levels in the Orleans
Avenue Canal (DPS #7) have been lowered considerably, while
remaining the same in the London Avenue Canal (DPS #3 and #4)
and risino- slightly at St. Charles. The decreased level in the
Orleans Avenue Canal (DPS #7) is due to the fact that all water
pumped by DPS #7 was treated with NaOCl while only a portion of
the storm water pumpage at the other stations was disinfected.
Evidently this increased level of treatment at DPS #7 and
served to lower the long term total coliform levels. The
total coliform increase at St. Charles was probably due to the
development of the area, with the attendant higher runoff
coefficient. The statistical chemical and physical results
of the routine sampling program for DPS #3, #4, and St. Charles
94
-------
CO
TABLE 11
DPS #7 - PRE AND POST-CONSTRUCTION EVALUATION PROGRAM:
MEANS AND STANDARD DEVIATIONS OF CHEMICAL AND PHYSICAL PARAMETERS
PRE-CONSTRUCTION
Mean (A) SD
POST-CONSTRUCTION
Mean (A) SD Mean (G)
SAL
TEMP
NH3
COD
C12D
pH
DO
TSM
25.
68.
3.
7.
4.
25.
6
3
5
6
5
8
4.
44.
2.
0.
3.
26.
6
8
4
4
1
4
1853.
24.
0.
77.
3.
7.
5.
28.
1
2
6
0
5
2
7
0
2943
6
0
39
0
0
2
16
.6
.1
.8
.4
.9
.5
.3
.3
827.
21.
0.
67.
3.
7.
5.
23.
7
3
2
7
3
2
1
6
-------
to
01
w
>
M
H
3
2;
W
CJ
«
W
a,
5 Yr« Base Period ©—
Pre-Construction
Post-Construction
/o' /o
Total Coliforra
FIGURE 39. LONDON AVE. CANAL (DPS #3 £ 4) TOTAL COLIFORM LEVELS
FIVE YEAR BASE PERIOD, PRE-CONSTRUCTION EVALUATION £
POST-CONSTRUCTION EVALUATION
/O
-------
/oo
90
London Avenue Canal
B/ /
5 Yr. Ease Period O
Pre-Construction A
Post-Construction D
O
FIGURE HO.
/O /O
Fecal Coliform
LONDON AVE. CANAL (DPS #3 S U) FECAL COLIFORM LEVELS
FIVE YEAR BASE PERIOD, PRE-CONSTRUCTION EVALUATION £
POST-CONSTRUCTION EVALUATION
-------
UD
00
/oo
90
80
TO
' 6O
O
w
o
cu
O
Orleans Avenue Canal
5 Yr. Base Period •
Pre-Construction A
Post-Construction B
/O
Total Coliform
/O
/O
s
FIGURE HI.
ORLEANS AVE. CANAL (DPS #7) TOTAL COLIFORM LEVELS
FIVE YEAR BASE PERIOD, PRE-CONSTRUCTION EVALUATION
& POST-CONSTRUCTION EVALUATION
-------
ID
(£>
5 Yr. Base Period O-
Pre-Construction £>-
Post-Construction D-
/O /O
Fecal Coliform
/O
/O
FIGURE 42
ORLEANS AVE. CANAL (DPS #7) FECAL COLIFORM LEVELS
FIVE YEAR BASE PERIOD, PRE-CONSTRUCTION EVALUATION
£ POST-CONSTRUCTION EVALUATION
-------
o
o
St. Charles Avenue
5 Yr. Base Period ® —
Pre-Construction
Post-Construction
/O
Total Coliform
JO
FIGURE 43. ST. CHARLES REACTION BASIN (ST. .CHARLES DPS) TOTAL COLIFORM LEVELS
FIVE YEAR BASE PERIOD, PRE-CONSTRUCTION EVALUATION 8 POST-
CONSTRUCTION EVALUATION
-------
/oo
90
60
70
w
>
H
o
H
2;
M
O
W
eu
St. Charles Avenue
5 Yr. Rase Period O—
Pre-Construction A-
Post-Construction D -
/O
/O
Fecal Coliform
/O
FIGURE
ST. CHARLES REACTION BASIN (ST. CHARLES DPS) FECAL COLIFORM LEVELS
FIVE YEAR BASE PERIOD, PRE-CONSTRUCTION EVALUATION g POST-
CONSTRUCTION EVALUATION
-------
o
to
TABLE 12
DPS #3 - PRE AND POST-CONSTRUCTION EVALUATION PROGRAM:
MEANS AND STANDARD DEVIATIONS OF CHEMICAL AND PHYSICAL PARAMETERS
PRE-CONSTRUCTION
Mean (A) SD
POST-CONSTRUCTION
Mean (A) SD Mean (G)
SAL
TEMP
NH3
COD
C12D
pH
DO
TSM
25.1
—
72.9
3.3
7.3
4.3
25.6
4.9
—
62.9
1.4
0.4
2.4
23.7
1553.0
24.0
0.4
71.5
3.2
7.1
5.1
28V4
2550.2
6.5
0.5
35.6
0.9
0.8
2.8
20.4
636.4
23.1
0.1
64.4
3.0
6.6
3.0
22.9
-------
o
CO
TABLE 13
DPS #4 -PRE AND POST-CONSTRUCTION EVALUATION PROGRAM:
MEANS AND STANDARD DEVIATIONS OF CHEMICAL AND PHYSICAL PARAMETERS
PRE-CONSTRUCTION
Mearv (A) SD
POST-CONSTRUCTION
Mean (A) SD Mean (G)
SAL
TEMP
NH3
COD
C12D
PH
DO
TSM
24.
—
81.
3.
7.
5.
27.
9
3
5
6
4
1
5.
—
60.
1.
0.
2.
37.
2
1
4
4
0
0
1596.
24.
0.
75.
3.
7.
5.
27.
3
3
3
5
2
2
6
9
2470.
5.
0.
37.
0.
0.
2.
18.
5
6
3
4
8
5
8
3
777.
23.
0.
67.
3.
7.
3.
21.
2
9
1
6
1
1
6
6
-------
o
-p
TABLE 14
ST CHARLES - PRE AND POST-CONSTRUCTION EVALUATION PROGRAM:
MEANS AND STANDARD DEVIATIONS OF CHEMICAL AND PHYSICAL PARAMETERS
PRE-CONSTRUCTION
Mean (A) SD
POST-CONSTRUCTION
Mean (A) SD Mean (G)
SAL
TEMP
NH3
COD
C12D
pH
DO
TSM
24.
—
80.
3.
7.
5.
51.
3
0
6
6
2
3
5.
44.
1.
0.
2.
32.
8
4
5
3
1
2
1389.
24.
2.
114.
2.
7.
3.
37.
8
6
6
3
8
2
3
8
2269.
5.
1.
36.
0.
0.
2.
21.
9
0
1
4
8
*
I
3
703.
24.
2.
107.
2.
7.
2.
32.
7
3
3
1
7
2
6
7
-------
are listed in Tables 12 through 14 and show the same properties
as the data for DPS #7. Thus, with the exception of lower
fecal coliform levels in each outfall canal, lower total coliform
levels in the Orleans Avenue Canal (DPS #7), and slightly
higher total coliform values at St. Charles, there appear to
be no significant long term changes in the parameters due to
NaOCl addition. However, the time base for this data is only
17 months and it is possible that long term effects might be
demonstrated after years of treatment. Only continued treat-
ment and sampling can provide the answer-
Storm Operation
Operational data was gathered at DPS #3 and #7 during low
volume pumpage operations. Data was available from St. Charles
and DPS #4, but the amount was not sufficient to provide
statistical parameters which would be valid.
Samples were taken in the suction bay of DPS #3 and #7 at four
minute intervals during low volume pumpage rates and composited.
Samples were then analyzed for standard sanitary parameters
Cpg 88). The results for 11 storm sampling episodes from A
at DPS #3 are given in Table 15.
TABLE 15
DPS #3 - STORM SAMPLING, BACTERIAL,
CHEMICAL, AND PHYSICAL RESULTS
PARAMETER MEAN PARAMETER MEAN
TOTAL COLIFORM 1.2xl07 pH 7.4
org/lOOml r
FECAL COLIFORM 3.7x10 TSM - mg/1 228
org/lOOml
ENTEROCOCCI 5.6xl04 VSM - mg/1 22
org/lOOml
SAL - mg/1 739.0 TOTAL SOLIDS 2453
mg/1
COD - mg/1 140.0 NH3 - mg/1 10
C10D - mg/1 2.4 TEMP - °C 24.4
1 BOD 16
As can be seen, there were no significant differences in the
parameter levels between the pre and post construction suction
bay data. There were slightly elevated COD and TSM values,
but these are expected during the initial "flushing" of the
drainage system. Results for DPS #7 are comparable as can be
seen in Table 16.
105
-------
TOTAL
COLIFORM
org/lOOml
FECAL
COLIFORM
org/100ml
ENT,
org/lOOml
10
10 -•
10
10'
10 "
10°--
0 144
Time
POST-CONSTRUCTION AFTER GROWTH STUDY
DPS #3 2-2-72
FIGURE 45. DPS #3 STORM AFTERGROWTH STUDY
106
-------
o
-o
FIGURE 46. DPS #7 - ORLEANS AVE. OUTFALL CANAL
-------
TABLE 16
DPS #7 - STORM SAMPLING, BACTERIAL,
CHEMICAL, AND PHYSICAL RESULTS
PARAMETER
TOTAL COLIFORM
org/lOOml
FECAL COLIFORM
org/lOOml
ENTEROCOCCI
org/lOOml
SAL - mg/1
COD - mg/1
C12D - mg/1
MEAN
3.5x10
2.5xlO!
1.3x10
643
71
2.5
PARAMETER
pH
TSM - mg/1
VSM - mg/1
TOTAL SOLIDS
mg/1
NH3 - mg/1
TEMP - °C
BOD
185
.3
23.3
18
It should be noted that the levels of those parameters
normally indicating pollution of water are much lower than
in sewage.
After bacterial, chemical, and physcial tests were performed
on samples taken during the storm operation, aftergrowth
samples were stored at 20°C in an incubator. A typical set
of results for DPS #3 is shown in Figure 45. The aftergrowth
data demonstrated the characteristics of bacterial growth
available in the literature as discussed in Section 9.
Logarithmic growth for the total coliform values is seen
followed by the decreasing growth phase and eventual dieoff.
Significantly, the fecal coliform densities did not increase
during the laboratory aftergrowth study. The enteroccoci
levels also appeared to demonstrate the classical growth and
dieoff characteristics.
Storm Profiles
Detailed records of 16 high volume pumping operations were
taken at DPS #7 (see Table 10, pg. 91). A high volume
pumping operation was defined as storm water pumpage in excess
of 500 cfs for more than 30 minutes. During the period of
pumping and disinfection, four water samplers vrere in operation.
Sampler A, located at the entrance of the feeder canal into
the suction bay, took samples at four minute intervals. Sampler
B, in the discharge bay, also took samples at four minute
intervals. Further downstream Sampler C, 0.25 miles from the
108
-------
station, took samples at fifteen minute intervals while
Sampler D, 1.50 miles from the station, sampled at 30 minute
intervals. The location of the samplers can be seen in
Figure 17 (pglOO). The results of the storm profiles can
be explained by the physical characteristics of the drainage
system, the empirical disinfection equation, the effects of
diffusion and dispersion, and microbiological growth patterns,
NaOCl is fed to the water entering the suction bay at DPS #7
just after passing the intake for Sampler A. The suction bay
is relatively large and can act as a storage reservoir. This
introduces the first of several time delays, T ,. This delay
is the effective time for treated water from Aato reach B.
Since there are several different pumps which can operate
singly or in combination, T . can vary from approximately
five to twenty minutes. This first delay factor is extremely
important from the standpoint of NaOCl addition since it
represents the closed loop delay time for the operator in
controlling the residual level. A delay of this magnitude
normally causes unstable behavior in a feedback loop.
Once the disinfected water leaves the discharge bay at DPS
#7, it flows into the Orleans Avenue outfall canal (Fig. 46).
Sampler C, is located 0.25 miles downstream and the volume
of water between B, the discharge bay, and C introduces a
second delay time, T, . The factors influencing T, are the
rate of storm water pumpage, tidal levels and flow in the
outfall canal, channeling of the storm water flow, and
diffusive and dispersive effects. The channeling occurs
since the discharge bay is divided by partitions which act
as short flow nozzles. The delay Tbc can be calculated by
comparing the corresponding peaks in the bacterial levels
at B and C after correcting for decreased coliform levels
at C due to increased NaOCl contact time. A third delay
time, T ,, is introduced by the volume of water between C
and D. The delay, T ,, is influenced by the same factors
as T, , but tidal, diffusion and dispersion effects are
much more important than channeling. Additionally, if the
quantity of storm pumpage is not sufficient to displace the
water between C and D, then diffusive effects with a time
scale of days or weeks predominate. Assuming a constant
pumping rate of 550 cfs, and neglecting the other complex^
factors, the time delays on a volumetric displacement basis
at DPS #7 are given in Table 17.
109
-------
TABLE 17
DPS #7 : VOLUMETRIC TIME DELAYS
SAMPLING POINTS
A - B B - C C - D B - D
T T(min) "8-20 36 180 216
The actual decrease of bacterial levels by NaOCl is governed
by the emperical relationship. n
E =
Where E is the kill efficiency, t is the contact time during
which a residual is present, c is the concentration of
available disinfectant, and n is the constant of the reaction.
It should be noted that this equation holds only after the
chlorine demands of all other reducing compounds are satisified
and a residual is present.
When NaOCl is added to the storm water it is immediately
hydrolyzed,
NaOCl + K20 ? NaOH + HOC1
The HOC1 ion then equilibrates with its dissociated charged
ions.
HOC1 ^ H+ + OC1~
It is generally accepted that the neutral HOC1 particle dis-
rupts the cell to a greater extent than the OC1" ion. The
HOC1 molecule is thought to interfere with cell respiration
by reacting with enzymes and this destroys the cell. The
dissociation constant for HOC1 is dependent on temperature,
pH and levels of nitrogenous reducing compounds. Elevated
temperatures shift the equilibrium to the right as do
alkaline pK levels. Nitrogenous compounds convert KOC1 to
chloramines which are much less effective as disinfectants.
This effect is also dependent on pH with the maximum conver-
sion occurring at pH = 8.4.
The results of a storm profile taken at DPS #7 on November 13,
1972 are given in Figures 47 to 49. This storm profile was
selected because most of the various facets of a treatment
episode are demonstrated. The remaining storm profiles are
included in the Appendix.
The most difficult aspect of the disinfection operation is
the maintenance of a pre-determined residual level. The
fluctuations in the C12R curve are typical (Figure 47),
110
The
-------
3000
H20
PUMP
RATE
cfs
mg/1
NAOCL
FEED
gpm
2000..
1000-
o
2.0
1.6--
1.2--
.8"
.4--
0
60
50--
40..
30-.
ifdii
20--
10"
o L
0
50
100
200
250
"Time (Win.)
Sampler A • Sampler C
Sampler B O Sampler D
PHYSICAL PARAMETERS DPS #7
STORM PROFILE 11-13-72
300
A
D
Figure 47. DPS #7 - STORM PROFILE PHYSICAL RESULTS
NOV. 13, 1972
111
-------
SAL,
mg/l
C.O.D,
mg/l
CL2D
mg/l
pH
10000
8000-
6000-
HQOO-
2000 -
0
300
200"
100 •
0
4.0-
3.0-
2.0.
1.0.
0
9.0
8.0 -
7.0.
6,0
I" \
9 \
"I \
. \
. * \
i \
•1 \
f 1 \
[1 \
r ^ \
0 ^
T \
k \
---_
;<^^-« .
/v- ' "^^~*"-"~ZLyv— -f^~~&~~ ~Q A n n T
- rf* -''"^ " ^"^ A—
& °^
'
]
50 ' 100 ' 150 '200 ' 250 ' 300
Time (Min.)
Sampler A ® Sampler C A
Sampler B O Sampler D D
CHEMICAL PARAMETERS DPS #7
STORM PROFILE 11-13-72
FIGURE 48. STORM PROFILE CHEMICAL RESULTS NOV. 13, 1972
112
-------
J.U
10 7-
t io6-
O
O
r-H
CO i A5.
E 10
CO
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10
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i
l~l
s
o „
o , A3
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w
•H 9
C 10 -
fO
bO
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101-
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9
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i\ x
\ N
1 \i---A \
1 V ^
i \ N
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\ >
\ V
(S &-•-£» — ^ — ^ — " ^
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\
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i
i
i
i
L A
9 ^^^n/ ^
i \
\
V
1 X.
^ "\
x N.
>^ — A— A »•
\
\
\
\
- 6--O— O- £©--A-^!sr-£ £k
1 1 1 1 1 1 1 1 1 1 !
TOTAL
COLIFORM
]
Sampler A •
Sampler B O
o-i_*t^n _ „. /*i A
bampler o tj
Sampler D O
FECAL
COLIFORM
i
j
50 100 150 200 250 300
Time (Min.)
BACTERIAL RESULTS DPS#7
STORM PROFILE 11-13-72
FIGURE 49. DPS #7 STORM PROFILE BACTERIAL RESULTS NOV. 13, 1972
113
-------
attempts of the operator to maintain the residual between
0.5 and 2.0 mg/1 are evident. The initial NaOCl feed rate
was 22 - 25 gpm. This feed rate is usually sufficient to
maintain this residual level with storm water pumping at
550 cfs if the chlorine demand approximates 3.5 mg/1. How-
ever, the initial feed rate required depends on the instan-
taneous strength of the NaOCl stored at the station. During
this storm the initial NaOCl feed rate was not adequate,
but since there is approximately a 20 min transport delay,
T b = 20 min, the operator is not aware of this initially.
The doubling of the^NaOCl feed rate to 44 gpm at the 20 min
mark was due to an increase in the pumping rate. Finally
at t = 24 min, the operator has the first indication that
he is not in the desired residual range. The operator then
increases the NaOCl feed rate to 53 gpm and maintains it
until t = 60 min. At this time the residual rises above
the 2.0 mg/1 range of the chart. The NaOCl feed rate is
then decreased to 22 gpm. It can be noted that the residual
does not begin to drop until t = 80 min._ The man-residual
feedback loop is obviously very unstable. The operator main-
tains the NaOCl feed rate at 22 gpm but the pumpage rate is
decreased to 550 cfs at t = 95 min. The residual again
rises and the operator decreases the feed rate 18 gpm which
is maintained until the cessation of disinfection. The
fluctuation of chlorine residual due to changes in demand
during the latter stages, and pumpage rate throughout the
storm profile is clearly seen. From Figure 48 it can be seen
that the chlorine demand is higher initially and thus requires
a greater NaOCl feed level to effect a residual. At t = 75
min the demand drops and the composite average remains constant
at 1.9 mg/1. Compositing of the samples obscures the minor
fluctuations in the demand seen at the end of the treatment
period.
The bacterial results of the treatment are plotted in Figure
49. As expected, influent coliform levels at A are very
high with total coliforms exceeding 107 org/lOOml while
fecal coliforms exceed 105 org/lOOml. At B, the initial
levels are comparable. A note of explanation is usefull here.
The initial coliform levels at B, C, D in the outfall canals
should be nearly equal and approximately two orders of
magnitude lower then the suction bay levels. However, the
location of B, in the discharge bay, causes the initial B
samples to approximate the conditions in the suction bay
almost immediately when pumping starts. In fact, due to
stirring up of the benthos, initial conditions at B are
sometimes worse than at A6 Occasionally, the samplers are
turned on prior to initiation of pumping and then the B, C,
and L values are comparable (App3-2). Once treated water
114
-------
reaches B, we see a rapid decline in the coliform levels to
less than 10^ org/lOOml. The uncertainty arises since the
plate counts were zero for this and higher dilutions. Moving
to C, we see that the initial total coliform value is "105
org/100 ml which holds until t = 45 min. The values then drop
to 104 org/lOOml as the first treated water reaches C. A second
drop to
-------
300-
6 200f
21
u>
H-
10 0--
Initial
Sampler A ®
Sampler B O
Time
Final
Sampler C A
Sampler D D
FIGURE 50. DPS #7 - POST-CONSTRUCTION EVALUATION PROGRAM
AVERAGE TOTAL SUSPENDED MATTER INITIAL 8 FINAL
SAMPLES
116
-------
TABLE 18
DPS #7 - MAXIMUM COLIFORM REDUCTION FOR SIXTEEN STORM PROFILES
Date
12/7/71
2/7/72
3/2/72
3/9/72
3/19/72
5/11/72
5/12/72
6/9/72
7/5/72
7/12/72
7/13/72
7/20/72
9/30/72
10/22/72
11/4/72
11/13/72
C1R - B min.
mg/1
ft*
ft*
ft*
ft*
ft*
.35
.52
.22
.45
.56
.28
1.4-0
1.26
.45
.35
2.00
A
IO7
IO7
IO7
IO7
IO7
IO6
__
IO7
io6
IO7
io6
IO7
IO7
IO7
IO7
io7
TC Values
B min.
IO5
io4
IO5
IO4
IO4
io4
10 3
io5
IO3
IO3
IO3
IO2
IO3
IO3
IO2
IO1
C min.
__
3
5
IO4
IO3
IO3
IO3
io4
IO3
io3
IO3
2
IO2
IO3
IO3
io2
Mag.
B/A
2
IO3
IO2
IO3
IO3
IO2
__
IO2
IO3
IO4
IO3
IO5
io4
IO4
IO5
io6
Red
C/A
__
io4
io2
io3
io4
io3
__
io3
IO3
io4
io3
IO5
IO5
io4
If
io5
C/B
10J
10J
10J
10J
10J
10
10
10
L
10
10'
10
10'
10C
10"
10
10'
10'
105
10'
FC Values
B min.
102
10'
10J
10'
10'
10'
10
101
10J
10J
10J
C min.
10J
10J
10'
10J
10J
10J
10'
10
101
10J
10J
10'
10J
Mag. Red. - PC
B//
10'
C/A C/B
10" 10'
10' 10'
IO2 IO2
IO3 IO4
10J
10J
102 103 101
102 103 101
10S 105 —
103 103 -
103 103 —
104 104 -
io4 io4
104 IO3
IO4 IO4
** Not Available
-------
result in higher levels of coliform reduction. The effect of
the increased contact time is also seen occasionally. The
occurrence is not uniform since little effect will be demon-
strated at high dosage levels. At the lower residual levels
mixing with untreated water may occur between B and C when
channeling is present and result in higher bacterial levels
at C. However, the effect of contact time can be used to
advantage by treating the water at lower residual levels,
i.e., 0.5 mg/1.
The chlorine residual analyzers utilized during this project
measured total available chlorine. Thus, free and combined
chlorine could not be separated. However, increased levels
of kill were found with increased residuals. From a considera-
tion of the strom profiles, chlorine residua.ls greater than
0.5 mg/1 resulted in 99.99% or greater reduction of bacterial
densities. The effects of contact time could be seen when
bacterial levels at C were consistently lower than comparable
levels at B. Unfortunately, it was not possible to ascertain
statistically the relative importance of each factor in the
treatment process due to a lack of point A samples. The
sampler inlet at A (Figure 51) was located at the entrance
of the feeder canal into the suction bav.
Figure 51 - Point A - Sampler Inlet at DPS #7
No problems were encountered at low flow rates, but during
high flow rates the sample head would tilt breaking primeJ
118
-------
on the sample pump and no further samples could be taken.
During one very high flow rate the sampler head was dislodged
entirely. An attempt was made to move the sampler inlet to
a protected area to the side of the feeder canal, but this
was unsatisfactory since the samples taken no longer repre-
sented the influent conditions. A complete redesign of this
sampler inlet would be required if further studies are to be
performed. However, on the basis of storms where A values
were available, it could be seen that only a slight decline
in initial coliform levels occurred (App. 1-3).
The main objective of the project was to decrease the total
and fecal coliform levels in the storm water which subsequently
reached Lake Pontchartrain by means of the outfall canals.
By analyzing the results of individual storm profiles, this
goal appeared to be well in hand. Except for a pre-residual
period at the initiation of pumping, coliform levels for most
of the storm water pumped were decreased by four or more
orders of magnitude (>99.99%) to levels below 1000 org/lOOml.
However, when storm profiles were taken on May 11 and 12,
1972 and July 12 and 13, 1972 (App. 6, 7, 10 & 11) it was
noticed that total and fecal coliform levels which had been
reduced to 103 org/lOOml and 101 org/lOOml, respectively,
had recovered to levels normally present in the canals
(106 org/lOOml, 105 org/lOOml). At first it was thought that
the levels at B and C were being increased by lake water
entering the outfall canals. However, salinity levels at
B and C on the second day had not recovered to their normal
levels and were at the same level as when pumping had ceased
on the previous day. This is shown by comparing App. 6-2 and
7-2 where salinity" levels for May 11, 1972 and May 12, 1972
are plotted.
On May 11, 1972, the normal increase in salinity levels as
one proceeds downstream toward the lake is present. Once
pumping begins, the salinity levels drop as the treated, low
salinity water from A reaches B and C. As can be seen, no
treated water reaches D. On May 12, the original salinity
levels at B, C, and D are all very low. Evidently, the
treated water diffused to D in the twenty-four hour period
between pumping episodes. Thus, the coliforms appeared to
regrow rather than being imported from the lake by tidal
action.
To explore this behavior further, an aftergrowth study was
initiated at C. So that the course of bacterial regrowth in
the natural environment of the outfall canal could be deter-
mined, sampler C was utilized to take samples at two hour
intervals for thirty hours after cessation of pumping^and
disinfection. The samples were then analyzed and coliform, pH,
119
-------
TOTAL
COLIFQRM
org/100ml
10 -•
FECAL
COLIFORM
org/lOOml
io -•
103-
io:
10
o—o- ex'
o or
SAL,
mg/l
pH
POST CONSTRUCTION AFTER GROWTH STUDY DPS #7
SAMPLING POINT C 10-22-72
FIGURE 52. DPS #7 - POST-CONSTRUCTION EVALUATION PROGRAM
STORM PROFILE AFTERGROWTH STUDY
120
-------
and salinity levels were determined. The results are shown in
Figure 52. The original dip in the curve is probably due to
dieoff of organisms which began after contact with NaOCl. This
effect ceases after six hours and there is a uniform, possibly
logarithmic, regrowth of total and fecal coliform organisms.
It is believed that the reading at T = 12 hr is an analytical
error since no concurrent increase in fecal coliform is noted.
Total coliforms increased to 10^ org/lOOml which approximates
the normal level in the Orleans Avenue canal. Significantly,
the fecal coliforms only recovered to 10^ org/lOOml, This
level is approximately two orders of magnitude less than was
ordinarily present in the Orleans Avenue canal. This could
explain the long term decrease in the fecal coliform levels
observed in the routine data.
Although additional aftergrowth studies with better controls
would have to be carried out to substantiate these observa-
tions, the regrowth phenomenon is a well known microbiological
event. In order to clarify the implications of coliform
regrowth with respect to the goals of the projects the micro-
biological aspects of disinfecting bacterially polluted storm
water had to be considered.
,121
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SECTION X
MICROBIOLOGICAL ASPECTS OF STORM WATER AND DISINFECTION
GROWTH
In order to explain certain observations made during the Pre-
Construction and Post-Construction Evaluation Programs, it is
necessary to refer to the microbiological aspects of disin-
fection of storm water (7, 8). If storm water is disinfected
through use of NaOCl (or any disinfectant) the number of
coliforms, pathogens, etc, in the storm water is reduced to a
very low level. If this small number of microorganisms is
considered analogous to a mass of organisms in a bacteri-
ological culture medium, the growth curve9 under favorable
conditions, would look like Figure 53. ~~ ~~~~~~~~"~~
The growth of the microorganisms has several phases. Loga-
rithmic growth starts a short time after the residual chlorine
level falls to zero and the remaining microorganisms come
into contact with the nutrients in the storm water. In the
logarithmic growth phase there is always an excess of food
around the microorganisms« The rate of metabolism and growth
is limited, in this case, only by their ability to process
the nutrients in the polluted storm water. At the end of the
logarithmic phase the microorganisms are growing at the
maximum rate. At the same time they are removing organic
matter from the water at their maximum rate- Needless to say
the limitations of food causes the rate of growth to decrease
in the declining growth phase. As the microorganisms lower
the nutrient concentration, the rate of growth decreases.
When growth ceases, the nutrient concentration for the species
is at a minimum and the organic matter still in the waste
water is in equilibrium with the number of microorganisms.
For coliform bacteria the time base for the log growth and
the^declining growth phases is approximately 24 hours. Fol-
lowing the declining growth phase, the number of micro-
organisms remains constant during the stationary phase. Once
the nutrient levels are lowered below the critical level die
off begins.
The growth pattern of microbial organisms can explain several
observations of the Pre and Post-Construction Evaluation Pro-
grams. During the pre-construction program, a gradual die
off of bacteria in the outfall canals was noted with time
after pumping. It can be seen that the bacteria originally
122
-------
CO
0)
-P
O
M-i
O
tfl
fc
0)
M
O
D
A. Lag Phase
B. Accelerated - growth phase
C. Exponential phase
D. Stationary phase
E. Decline phase
Time (Hour)
BACTERIAL GROWTH CURVE
FIGU; r. -S3. BACTERIAL GROWTH CURVE
-------
present in the water rapidly enter the stationary and die
off phase of growth with its gradual decrease in the number
of microorganisms. This accounts for the decrease in bac-
terial levels noted during the Pre-Construction Evaluation
Program, In the Post-Construction Evaluation Program, dis-
infection with NaOCl decreased the total number of organisms
in the water to very low levels while having only a negli-
gible effect, from the microbial view, on the amount of
organic material present as nutrient substrate. Thus, the
coliform bacteria surviving disinfection are in the logarithmic
growth phase and the declining growth phase for the first 24
to 30 hours. This results in a rapid recovery of the bacterial
population to that level normally found in the outfall canal.
This rapid recovery, once the residual chlorine level has
dropped to zero3 casts serious doubt on the ability of the
project to attain its goal of reducing the coliform bacteria
count in the water discharged into the surrounding recre-
ational areas. It was apparent that unless a residual
chlorine level is kept in the water in the outfall canal at
all times, a. rapid recovery of indicator bacteria takes place.
Since there are over 1U,000,000 cu ft of water and associated
benthos in most of the outfall canals, it is not economically
possible or ecologically desirable to keep a chlorine residual
in the outfall canal at all times. This led to a reevaluation
of the goals of the project.
Origin of Pathogens
The primary reason for treating water is to remove human spe-
cific pathogens from it. Thus, disease will not be caused
in humans when polluted water subsequently comes into contact
either with the skin or enteric system. Human specific
pathogens are normally transmitted to water by pollution of
fecal origin. The access of fecal pollution to water may
add a variety of intestinal pathogens. The most common
pathogens include strains of Salmonella, Shigella, Leptospira,
enteropathogenic Eseherichia aoli , Pasteurella, Vibrio,
Myccbacterium., human enteric viruses, cysts of Endamoeb a
histolytica, and hookworm larvae.
These pathogens may be found in sewage, streams, irrigation
waters, wells, and tidal waters. However, the isolation of
pathogens from the water environment has been infrequently
performed because laboratory methods of isolation and iden-
tification remain too cumbersome for routine use. For this
reason, the presence of total and fecal coliform has been
used as an indication that other pathogenic organisms may
be_ present. The rational behind this method is that total
and fecal coliforms are present in the alimentary tract of
124
-------
humans, as are pathogens when the host is infected.
Originally indicator bacterial tests included the coliform
group as a whole. However, Eiijkman (9) introduced a modifi-
cation which distinguished between soil based coliform and
enteric coliforms. In this modification, those coliform
which are found in the alimentary tract of warm blooded
animals and capable of growth at the normally inhabiting tem-
perature of 44.5°C are operationally defined as fecal coli-
forms. Since both soil based and enteric coliforms could
multiply at 37°C this combination was designated as the total
coliform group. The monitoring of sewage for pathogens using
total and fecal coliform indicators has been demonstrated to
be an excellent epidemiological tool for monitoring water
borne diseases that may be prevalent in the community at
the moment. However, it must be remembered that this observation
has its greatest utility when the fecal material is_ known
tp_ be of human origin.
While the microbial discharge of warm blooded animals is
usually not harmful to humans, pathogens may be found in the
intestinal tract of warm blooded animals.. The~s~e sources
include animal pets (10), livestock (1J), poultry (12),, and
the wild animal community (13). The animals come into contact
with human specific pathogens through contaminated food and
water sources (14-) and may themselves come infected or serve
as carriers. Among the cold blooded animals, fresh water
fish and turtles may harbor human pathogens after exposure to
contaminated water or food sources and carry these organisms
to recreational areas (15), This occurrence of pathogens in
domestic animals and wildlife illustrates the concern about
fecal pollution from all warm blooded animals and not just
from man. However, it must be remembered that the human spe-
cific pathogen may loose _its pathogenicity when passing through
any link of the chain;Infected host, fecal pollution, non-
human or water host, exposed humans.
In the present project, the effect of environment once the
human specific pathogen leaves its host is of the utmost im-
portance. In most cases the path traveled by a hypothetical
pathogen will be a cross connection between the sanitary and
storm sewerage systems for human pathogen sources and storm
water runoff for animal borne pathogens. The possibly con-
taminated storm water is collected by the drainage system and
pumped into the outfall canals. Once in the outfall canals,
the storm water can subsequently reach recreational areas
where humans may be exposed if_ any pathogens are present.
Thus, it is necessary to investigate the survivabiTity of
pathogens in the storm water once they leave the host organism.
125
-------
Effect of Environment on Pathogen Survival
The survival of Salmonellae in the aquatic environment is
influenced by the same factors that control the persistence
of fecal pollution indicators. Nutrient rich waste, lower
stream temperatures, cold blooded host, and a source of_
Salmonellae can produce an impact downstream. However in
several studies (16), Salmonellae were added to individual
storm runoff samples and .stored either at 10°C or 20°C to
approximate the water temperature in the environment. Results
showed a 99% attrition of Salmonellae in the storm water
samples held ten days at 20°C while 5% of the bacteria
persisted beyond 14 days in runoff water stored at 10°C.^
However, in no instance did Salmonellae levels increase iH
the storm water samples.
Another water borne pathogen causes leptospirosis, This
disease is due to a group of coil-shaped, actively motile
bacteria, Leptospirae. These pathogens gain access to the
blood stream through skin abrasions or mucous membranes and
cause lesions involving the kidneys, liver, and central
nervous system. Although leptospires from infected reservoir
hosts may be present throughout the year, infections in the
United States are most frequent during the recreational
season (21). Again several variables:/.affect the survival of
leptospires in the storm water environment. At low temperatures
multiplication of these organisms is retarded, but persistence
is increased over that for summer temperature levels.
A commonly identified cause of intestinal disease in the
United States is exposure to Shigella. This may occur from
person to person contact and contaminated drinking water or
food. The survival of shigella strains once they enter the
water environment is limited by many ecological factors. As
observed with Leptoapira and enteric viruses, persistence of
Shigella in water is much better when the total bacterial
population is low (17, 18). Most interesting is the negative
reaction to formic and acetic acids produced by coliform
organisms. The coliform group acid production apparently has
a bacteriostatic to bacteriocidal effect on the Shigella
strain (19). A second important factor is water pH. Experiments
on survival and recovery of S. flexmevi in the intestinal
tract of carp and bluegill indicated regrowth when incubated
at 20°C in a 1% fecal suspension which was free of coliform
and had a pH of 7.6 to 8.3. However, several experiments in
1% fecal suspensions and an initial pH of 7.2 showed a rapid
die off of Shigella within several days (20). Water temperature
also influences the levels of Shigella. That is, it survives
longer at lower temperatures as do all other bacteria.
126
-------
The salinity level of the environment also influences the
survival^of leptospires. The organisms can survive more than
10 days in lake water of low salinity. In lake and river
waters with moderate salinity levels (70 - 7000 mg/1 chloride),
leptospires survived for less than one week. In sea water
with a salinity of 13,000 to 17,000 mg/1 chloride, survival
time was reduced to less than one day (22). Another factor
that influences leptospire persistence in the water environ-
ment is the density and composition of the microbial population.
Leptospires are inhibited rapidly when mixed with fecal
material at either 5°C or 37°C (23). Also, raw sewage with
its varied microbial population shortens survival to 12 to
11 hours (2«O.
Serious intestinal disease in young children is often due to
infection by enteropathogenic E. ooli. E. ooli generates an
enteric disease characterized by profuse watery diarrhea,
nausea, and dehydration with a general absence of fever.
A causal'relationship of E. ooli in humans due to exposure
to animals has yet to be established. When E. ooli is
found in fresh or brackish water,,its occurrence indicates a
recent introduction of fecal contamination. Multiplication of
E. ooli is observed in untreated cannery waste, poultry
processing waste, and raw domestic sewage. These discharges
can all be characterized as having warm temperatures and
large quantities of bacterial nutrients. After dilution by
better quality water downstream or exposure to waters with
high salinity levels, multiplication of E. ooli is
suppressed (25, 26). Thus, environmental forces can produce
a sharp die off of E. ooli purification with only 10% viable
organisms present after two to five days has been found (27).
One other important observation has been the persistence of
Vibrio choleras in some polluted aquatic environments, although
the organisms should persist only a short time. This
contradictory behavior was noticed in persistence of V. oholerae
from the Hoogly River in Calcutta, India (28). Even after
chlorination (2.0 to 3.0 mg/1, ten minute contact time)
cholerae, vibrios, and salmonella are found (29). It is
probable that pathogenic bacteria present in the poor quality
water are protected in clumps of particles from exposure to
the chlorine during the disinfection period. Thus, there is
a persistence of pathogenic bacteria in very turbid waters.
127
-------
Application to Outfall Canals
In the urban community, fecal contamination in separate storm
water runoff is derived from the fecal material deposited on
soil by dogs, cats, and rodents or sewage cross connection.
Survival of human specific pathogens in the water environment
is influenced by many of the ecological forces previously
discussed. These factors need to be taken into consideration
in elucidating the fate of pathogenic organisms in the aquatic
environment. The main factors are:
1. Temperature.
2. Interference of growth due to competing
microorganisms in the water.
3. Time since introduction of microorganisms
into water.
4. The effect of substances such as NaOCl or
other inhibitory chemicals either from natural
or a man-made source.
5. The presence of solid material in the water
which can shelter the microorganisms from
attack.
For the particular treatment situation in the outfall canals,
the conditions are such that it is very unlikely that pathogens
could survive in any great number once disinfection has oc-
curred. Temperature in the outfall canals ranges from 60°F
to 85°F and thus, does not greatly enhance the survivability
of the organisms. Additionally, the solids level of the storm
water is low so that the number of enclosed organisms should
also be low. Also, the receiving stream has a moderate level
of salinity and thus organisms affected by increased osmotic
pressures should not fare well. Bacteriological studies are
indicated to confirm these conclusions for pathogens in storm
water. However, the fact that the environment in the dis-
charged storm water is not conducive to regrowth of fecal
organisms was demonstrated by the results of the long term
routine sampling, storm operation aftergrowth studies and the
storm profile aftergrowth study- Also, it should be noted
that the levels of indicator bacteria in the outfall canals
after disinfection and regrowth no longer provide the same
measure of possible pathogenicity of the storm water unless
new sources of pollution are present.
128
-------
Effluent Criteria
There is no doubt that the use of coliform groups as indicators
of contamination has been an extremely useful epidemiological
tool. However, once storm water has been disinfected, the
significance of the coliform group should be reevaluated since
the alternatives of continued chemical treatment or solids
removal are extremly costly. In addition, there are only three
possible spheres of disposal which can ultimately be used;
air, water, and land. The transfer of the problem from one
sphere to another occurs only at the cost of additional
expenditures of energy and, thus, more pollution. For the
particular case of large volumes of bacterially polluted storm
drainage water, it might be best to allow natural processes to
remove the nutrients if the original treatment with disinfectant
is adequate from health standpoints and the subsequent envi-
ronmental factors are not conducive to pathogen regrowth even
if coliform levels recover. Additional study is needed to
provide simple tests for pathogen detection and to determine
the effects of disinfection and subsequent environmental
factors on pathogens.
129
-------
SECTION XI
ECONOMICS
GENERAL
The addition of NaOCl to polluted storm water involves eight
major cost elements; amortization, land, manufacturing
facilities, transportation facilities, storage facilities,
chemical feed systems, chemicals, and operation and mainten-
ance. The first six are fixed investment costs while the
last two are dependent on the amount of storm water pumped
and the degree of treatment required. Sales taxes on
eauipment and freight charges were not included in the
calculations since they vary substantially with location
of the facilities. The cost of construction of the reaction
basin at St Charles was also neglected.
MANUFACTURING FACILITIES
The NaOCl manufacturing plant developed for this project was
of a novel design, subsequently patented, which can continu-
ously manufacture high strength NaOCl under atmospheric con-
ditions. As is usual in process development, the design and
construction costs were higher than one would normally expect
for a facility with which a great deal of experience had
been available. For this reason, design costs are not included
in the cost of construction of the plant. The fixed costs
of the various facilities at the manufacturing plant are
shown in Table 19. Table 20 shows the cost of manufacturing
1,000 gal. of 120 gpl NaOCl from the basic chemicals which
are delivered to and stored at the plant. The sums shown are
the average costs encountered during the project for producing
the NaOCl, As can be seen,the price $78/52/1,000 gal. of
120 gpl NaOCl is comparable with' commercially available NaOCl
at a much lower solution strength. It should be noted that
the water used for manufacturing and cooling of NaOCl is
provided at wholesale by the Sewerage and Water Board of New
Orleans. The cost for the water is only $.035/1,000 gal., and
was neglected.
FEEDING FACILITIES
The fixed costs of the feeding facilities at each pumping station
is shown in Table 21. The differences in the price of the
storage tanks at the various stations is due to differences in
130
-------
TABLE 19
FIXED COSTS : NaOCl MANUFACTURING PLANT
A. Equipment Item Cost
H20 Pumps $ 2,100.00
Refrigeration
Equipment 13,931.00
2 NaOCl Pumps 2,994.75
Heat Exchanger 2,975.00
NaOH Storage Tank 19,290.00
2 NaOCl Storage
Tanks 19,208.00
NaOCl Averaging
Tanks 201.96
Chilled Water
Pumps 950.25
Miscellaneous 11,496.73
$ 73,147.69
B. Construction 181,733.70
C. Supervision 27,516.75
TOTAL $282.398.14
131
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TABLE 20
AVERAGE COST OF MANUFACTURING NaOCl
(1,000 gals, of 120 gpl NaOCD
ITEM COST
Electricity $ 2.09
Labor 11«66
Chlorine 16.30
Sodium Hydroxide 47.47
Maintenance 1.00
TOTAL "78.52
TABLE 21
FIXED COSTS: NaOCl FEEDING FACILITIES
ITEM DPS #3 DPS #*» DPS #7 ST CHARLES
(2) NaOCl Storage
Tanks $19,208.00 $20,075.00 $24,453.00 $20,075.00
(2) NaOCl Pumps 1,593.83 1,593.83 1,593.00 1,593.83
Misc. Equip.
and Construction 47,279.04 45,353.00 57,186.00 33,700.48
Supervision 6,879.18 6,879.18 6,879.18 6,879.18
Sub Total $74,960.05 $73,901.01 $90,112.01 $62,248.49
TOTAL COST: $301,221.56
132
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TABLE 22
FIXED COSTS: CHEMICAL FEED SYSTEMS
ITEM
C12R Analyzers
Electronic Equ:
'water Samplers
DO Analyzers
Construction
$
nt
DPS #3
1968.75
4904.33
1166.25
7511.89
DPS #4
$ 1968.75
4904.33
2724.88
1166.25
7511.89
DPS #7
$ 1968.75
5121.00
10899.52
1166.25
7511.89
ST CHARLES
$ 1968.75
4904.33
5449.76
1166.25
7511.89
Sub Total $15,551.22 $18,551.22 $26,667.41 $21,000.98
TOTAL COST: $ 81,495.71
TABLE 23
TOTAL FIXED COSTS
NaOCl Manufacturing Facilities
Transportation Costs
NaOCl Feeding Facilities
Chemical Control Facilities
TOTAL COST
$ 282,398.14
35,960.04
301,221.56
86,945.47
$ 706,525.21
133
-------
the linings. The different physical characteristics of
pumping stations altered the construction costs. The increased
cost of the electronic equipment at DPS #7 is due to the fact
that it was ordered one year after the .other electronic
equipment. The prototype sampler used at DPS #3 was built by
the Sewerage and Water Board machine shop at the initiation
of the project and its cost was not included,
TRANSPORTATION FACILITIES
The cost of the two NaOCl transport trucks was $35,960.04.
The operation and maintenance cost of the trucks will vary
with the frequency and degree of treatment required, and
is neglected.
CHEMICAL FEED SYSTEMS
The cost of NaOCl feed and control systems at the various
stations is shown in Table 22. The figures here might in-
crease somewhat in subsequent facilities since a change in
the type of feed pumps or regular replacement of pumps is
indicated (pg ). However, if provision is made to completely
flush the pumps during the periods between operation, these
pumps might be used for the life of the manufacturing plant.
SUMMARY
The total fixed costs of hypochlorination are given in Table
23. Assuming a total life of 10 years for the facilities, and
an interest rate of 6%, the fixed costs are $53,600/yr.
The calculation of disinfection cost will be based on treating
storm water with a chlorine demand of 3.5 mg/1 so as to main-
tain a 1.0 mg/1 residual at all times. This requires a dosage
rate of 4.5 mg/1 (4.5 g/264,2 gal.). A conservative estimate
of the average decrease in.strength of the NaOCl in the field
was 4 g/l/wk. Assuming eight weeks storage before ultimate
use, 1,000 gal. of 120 gpl NaOCl manufactured at the plant
can ultimately treat 19,600,000 gal. of storm drainage water.
The average yearly pumpage of the ..four pumping stations in
the project is approximately 5x10 gal. if all pumpages are
considered. The yearly fixed costs are $53,600 and the
manufacturing cost of the NaOCl required to disinfect 5x10
gal. of storm water is $200,300. On this basis, the average
yearly cost of treatment would be $.000051/gal. of storm water.
134
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SECTION XII
ACKNOWLEDGEMENTS
Sewerage and Water Board of 'New Orleans
The support of Mr. E.F. Hughes, General Superintendent (Ret.),
Mr.^G. Joseph_Sullivan, General Superintendent, and Mr. D.D.
Modianos, Assistant General Superintendent, is acknowledged
with sincere thanks.
Mr. Crawford J. Powell, Assistant General Superintendent (Ret.)
made the original suggestion for the project and gave counsel
and support through the construction and early operational
phases.
Mr. Ray A. Beaman, Clark L. Fox, and Anthony H. Carver
gathered water samples, ran chemical analyses, and maintained
the storm water sampling equipment.
Mr. George Hopkins, Water Treatment Superintendent, and Mr.
William F. Wells, Water Chemist, directed and supervised
the sodium hypochlorite manufacturing facilities.
Mr. Louis Meridier and Mr. E.H. Arnold provided mechanical
and electrical maintenance support for the project.
Pavia-Byrne Engineering Corporation
Mr. Gerard S. Pabst, Jr. consulted on the microbiological
aspects of the project.
Sincere thanks are extended to Mrs. Joan Herzog, Miss Susan
Luttmann, and Miss Linda Herzog for their patience and
diligence in typing the final report.
Environmental Protection Agency
The help and support of Mr. Robert Killer, Project Officer,
is acknowledged with sincere thanks.
The guidance and encouragement of Mr. Frank Condon, Head-
queirters Staff Office of Research and Monitoring, Washington,
D.C., and Mr. George Putnicki, Director of Surveillance and
Analysis Division, Region 6, was greatly appreciated.
135
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SECTION XIII
REFERENCES
1. Pavia, E. H., and C. J. Powell, "Storm Water Disinfection
at New Orleans", JWPCF, 41:1, 591 (1969).
2. Geldrich, E. E., L. C. Best, B. A. Kenner, and D. J. Van
Donsel, "The Bacterial Aspects of Storm Water Pollution",
JWPCF, 40:1 1861 (1968).
3. Kendall, M. C., and A. Stuart, The Advanced Theory of
Statistics, Griffen, London, 1966.
4. Biguria, G., R. C. Ahlert, and M. Schlanger, "Distributed
Parameter Model of Thermal Effects in Rivers", 1969
Stream Pollution Abatement Conference, Rutgers University,
1969.
5. Dresnick, R., and W. E. Dubbins, "Numberical Analysis of
BOD and DO Profiles", J. Sanit. Engr. Div. : Proc. ASCE,
94;SA5, 789 (1968).
6. Verhoff, F. H., W. F. Echelberger, Jr., M. W. Tenney, and
P. C. Singer, "Lake Water Quality Predictions Through
Systems Modeling", 1971 Summer Computer Simulation
Conference, Boston, 1971.
7. Geldreich, E. E., "Water Borne Pathogens", Water Pollution
Microbiology, edited by Ralph Mitchell, John Wiley and
Sons, Inc.; 237 (1972).
8. Pelczar, Jr., M. J., and R. D. Reid, Microbiology, McGraw-
Hill Book Company, New York, 1958.
9. Eiijkman, C., "Die Garungsprobe bei 46°C als Hilfsmittel
bei der Trinkwasseruntersuchung", Centr. Bakt. , 37,742
(1904).
10. Galton, M. M., J. E. Seatherday, and A. V. Hardy,
"Salmonellosis in Dogs", J. Infec. Dis., 91, 1(1952).
11. Salle, A. J., Fundamental Principles of Bacteriology,
McGraw-Hill Book Company, Inc., New York, 1961.'
12. Quist, K. D., "Salmonella in Poultry as Related to Human
Health", U.S. Dept. of Agric., Report of National Plans
Conference, 24-30, November, 1962.
136
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13. Lafton, C. B., S. M. Morrison, and P. D. Leiby, "The
Enterd> aoteriaeeae of Some Colorado Small Mammals and
Birds, and Their Possible Role in Gastroenteritis in
Man and Domestic Animals", Zoonoses Res., 1, 277 (1962).
14. Summers, J. L., "The Sanitary Significance of Pollution
of Waters by Domestic and' Wild Animals : A Literature
Review", U. S. Dept. of Health, Education and Welfare,
P. H. S., Shellfish Sanitation Technical Report, 1967.
15. Janssen, W. A., and C. p. Meyers, "Fish : Serological
Evidence of Infection with Human Pathogens", Science,
159, 547 (1968). L
16. Andre, D. A., H. H. Weiser, and G. W. Maloney, J. Amer.
Water Works Assoc., 59, 503 (1967).
17. Wang, W. L. L., S. G. Dunlop, and P. S. Munson, "Factors
Influencing the Survival of Shigella in Wastewater and
Irrigation Water", JWPCF, 38, 1775 (1966).
18. Babbitt, H. E., J. J. Doland, and J. L. Cleasby, Water
Supply Engineering, McGraw-Hill Book Company, Inc., 1962.
19. Hentges, D. J., "Inhibition of Shigella flexmeri by the
Normal Intestinal Flora", J. Bacteriology, 97, 513 (1969).
20. Geldreich, E. E., and N. A. Clarke, "Bacterial Pollution
Indicators in the Intestinal Tract of Freshwater Fish",
Applied Microbiology, 14, 429 (1966).
21. Howell, D., "Leptospirosis in Dairy Cows", Vet. Rec., 84,
122 (1969).
22. Schuffner, W., "Recent Work on Leptospirosis", Trans._
Royal Soc. Trop. Mec. Hyg., 28, 7 (1939).
23. Clark, L., J. I. Kresse, R. R. Marshak, and^C. J.
Hallister, "Leptospira grippotyphosa Infections in Cattle
and Wildlife in Pennsylvania", J. Amer. Vet. Med. Assoc.,
141, 710 (1962).
24. Chang, S. L., M. B. Buckingham, and M. P. Taylor, "Studies
on Leptospiva iaterohaemorrhagiae", J._ Infect. Diseases,
82, 256 (1948).
25. Kittrell, F. W., and S. A. Furfari, "Observations of
Coliform Bacteria in Streams", JWPCF, 35, [36] (1963).
137
-------
26. Hanes, N. B., and R. Fragala, "Effect of Seawater Concen-
tration on Survival of Indicator Bacteria", JWPCF, 39,
97 (1967).
27. Mitchell, R., "Factors Affecting the Decline of Non-Marine
Micro-Organisms in Seawater", Water Research, 2, 535
(1968).
28. Gareeb, A. H. A., "The Detection of Cholera vibrios in
Calcutta Waters : The River Hoogly and Canals", J. Hygiene,
58, 2, (1960).
29. Sen., R. , and B. Jacobs, "Pathogenic Intestinal Organisms
in the Unfiltered Water Supply and the Effect of Chlori-
nation", Indian J. Med. Res., 57, 1220 (1969).
30. Fair, Gordon M., John C. Geyer, Daniel A. Okun, "Water
and Wastewater Engineering", Volume 2, Water Purification
and Wastewater Treatment and Disposal, John Wiley £ Sons,
Inc., New York, 1968.
31. Eliassen, Rolf, "Coliform Aftergrowths in Chlorinated
Storm Overflows", J. of the Sanitary Engineering Division,
Proc. ASCE, 94: SAl, 371 (1968).
32. New Orleans Board of Health, Personal Communication.
33. Chlorine Bleach Solutions, Bulletin No. 14, Solvay Technical
and Engineering Service, Allied Chemical Corporation, 1965.
138
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SECTION XIV
PROJECT PATENTS AND PUBLICATIONS
1. Patent 3,702,234 - A method for forming sodium hypochlorite
at atmospheric conditions from sodium hydroxide and
chlorine in proper proportions and under controlled
conditions to prevent the escape of unreacted chlorine to
the atmosphere; and to avoid the formation of sodium
chlorate.
2. Pavia, E. H., "Chlorination and Hypochlorination of Pol-
luted Storm Water at New Orleans", presented at the 31st
Annual Short Course for Water, Sewerage and Industrial
Waste Disposal, Louisiana State University, March 14, 1968.
3. Pavia, E. H. and C. J. Powell, "Stormwater Disinfection
at New Orleans", presented at 41st Annual Conference
of Water Pollution Control Federation, Chicago, 111.,
Sept. 22-27, 1968, also, JWPCF, 41:4, 591 (1969) 41:4.
4. Pavia, E. H. and C. J. Powell, "Hypochlorination of Storm
Water Run Off at New Orleans", presented at Annual Meeting
of American Shore £ Beach Preservation Association, New
Orleans, La., Nov. 14-16, 1968, Shore and Beach, 37:1,
(1969).
5. Brown, L. R.,E. H. Pavia, "Lake Pontchartrain Storm Water
Pollution Control Project", presented at American Society
of Civil Engineers Meeting on Water Resources Engineering,
New Orleans, La., Feb. 3-7, 1969.
139
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SECTION XV
GLOSSARY & ABBREVIATIONS
DEFINITIONS
Analysis of Variance - A statistical technique which analyzes
the variance which can be attributed to each of several
factors which were varied singly or combination.
Benthic Deposits - Deposits of living, bottom dwelling organ-
isms in a stream.
Cells - In Analysis of Variance a cell contains all the
replicate values for one position in a factorial arrangement.
Chlorine Demand - The demand for chlorine in a volume of water
caused by organic and inorganic reductants. This quantity is
defined as the difference between an initial chlorine concen-
tration in a specific volume of water and the total available
chlorine remaining at the end of a contact period.
Coliform, Coliform Bacteria - All the aerobic and facultative
anaerobic, Gram - negative, nonspore - forming rod shaped
bacteria which ferment lactose with gas formation within 48
hours at 35°C. Used as an indicator of bacterial pollution.
Crazing - Fine or small cracks in a surface.
Diffussion - The transport in a given direction at a point
in a flow due to the difference between the true convection
in that direction and the time average of the convection in
that direction.
Dispersion - The transport in a given direction at a point in
a flow due to the difference between the true convection
in that direction and the spatial average of the convection
in that direction.
Enterococci - A group of bacteria consisting of anaerobic
spore-forming rods which indicate recent fecal pollution,
sometimes referred to as fecal streprococci.
Factorial Arrangement - A method for apportioning the number
of tests required for an Analysis of Variance. Given the
formula N=X where X is the number of independent variables
and k is the number of levels (factors).
140
-------
Fecal Coliform - Coliforms derived from the gut of warm blooded
animals, test results expressed in terms of density in a given
volume of water.
Fibrous Glass Plastic - A laminar material having glass fibers
embedded in a plastic region to provide structural strength.
Membrane Filter Technique - A direct plating technique to
determine the density of coliform bacteria in a given volume
of water.
Multiple Tube Technique - A technique to determine the density
of"coliform bacteria in a given volume of water carried out by
dividing the sample into multiple portions and testing each
portion individually.
Nitrogen (Ammonia) - A product of microbiologic activity some-
times accepted as evidence of sanitary pollution in surface
waters.
ORP - Oxidation Reduction Potential - Oxidation Reduction
Potential (a precise measurement for the determination and
control of minute concentration of oxidant and reductants in
solution).
Pathogen - A microorganism capable of causing disease.
Sodium Hypochlorite - A salt of hypochlorous acid formed by
reacting chlorine with sodium hydroxide, which exhibits greater
stability than the acid. It is used for disinfection and
bleach in place of the acid.
Solids Series - A series of tests to determine the solids con-
tent of wastewater. They consists of the residue on
evaporation, total volatile and fixed residue, total volatile
and fixed suspended matter, dissolved matter, and settleable
matter.
Spectral Analysis - Statistical techniques which utilize the
Fourier or Laplace transforms of functions rather than the
functions themselves.
Stochastic - The property of being random with respect to
time.
Suspended Solids - The filterable residue in water.
141
-------
Thermal Coefficient of Expansion - A number of expressing
unit change in volume of a material due to a unit change in
temperature.
Ton Of Refrigeration - A unit of refrigeration equivalent to
288,000 BTU per day.
cfd - Cubic Feet per day
cfs - Cubic Feet per second
Cl~ - Chlorine
COD - Chemical Oxygen Demand - A measure of the oxygen equivalent
of that portion of the organic matter in a sample that is sub-
ject to oxidation by a strong chemical,oxidant.
DO - Dissolved Oxygen - The density of oxygen in solution in a
given sample of water.
DPS - Drainage Pumping Station
°F - Degrees Fahrenheit
gals. - Gallons
gpd - Gallons per day
gpl - Grams per liter
mg/1 - Milligrams per liter
ml - Milliliter
NaOCl - Sodium Hypochlorite
NaOH - Sodium Hydroxide
142
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SECTION XVI
APPENDICES
No. Title Page No.
1 Storm Profile, DPS #7, Dec. 7, 1971 144-146
2 " " Feb. 7, 1972 147-149
3 " " Mar. 2, 1972 150-152
4 " " Mar. 9, 1972 153-155
5 " " Mar. 19, 1972 156-158
6 " " May 11, 1972 159-161
7 " " May 12, 1972 162-164
8 " " June 9, 1972 165-167
9 " " July 5, 1972 168-170
10 " " July 12, 1972 171-173
11 " " July 13, 1972 174-176
12 " " July 20, 1972 177-179
13 " " Sep. 30, 1972 180-182
!4 " " Oct. 22, 1972 183-185
15 " " Nov. 4, 1972 186-188
143
-------
H20
RATE
cfs
Ci2R
mg/l
NAOCL
FEED
gpra
3000
2000 ..
1000 --
0
2.0
1.6f
1.2
.8
.4
0
60
50
40
30
20
10
0
Not Available
Not Available
70
80 120
Time (Min.)
160
200
240
Sampler A O Sampler C A
Sampler B O Sampler D D
PHYSICAL PARAMETERS DPS#7
STORM PROFILE 12-7-71
Appendix 1-1 Storm Profile, DPS #7, Dec. 7, 1971
-------
SAL,
iag /I
C.OJD.
mg/1
CL2D
mg/1
pH
10000
8000--
6000--
4000--
2000--
30
9.0
8.0"
7.O..
6.0
-h
-i i 1 1—
80 120 160
Time (Min.)
200
240
Sampler A • Sampler C A
Sampler B O Sampler D D
CHEMICAL PARAMETERS DPS #7
STORM PROFILE 12-7-71
Appendix 1-2 Storm Profile, DPS #7, Dec. 7, 1971
-------
&
o
o
H
w
•H
•fc
O
10
io7r
1-
io
00
10
10'
4-
TOTAL
COLIFORM
Sampler A •
Sampler B O
A
a
1
io5-
io4-
*
6
0
3 io3J
A A • A
^ ^ • •
9°
•H 2
c 10 -
re
O
io1-
VD— - '
1 ! 1 > 1 ! 1 1 1 1 1
Sampler I
FECAL
COLIFORM
40 80 120 160 200 240
Time (Min.)
BACTERIAL RESULTS DPS#7
STORM PROFILE 12-7-71
Appendix 1-3 Storm Profile Results, DPS
Dec, 7, 1971
-------
3000
H20
PUMP
RATE
cfs
CL2R
mg/l
NAOCt
FEED
gpm
2000 ..
1000--
o
2.0
1.6--
1.2--
.4--
0
60
50--
40--
30-.
20--
10-
Not Available
Not Available
0 24
Sampler A •
Sampler B O
-i i i —t
48 72
Time (Min.)
96 120
Sampler C A
Sampler D O
PHYSICAL PARAMETERS
2-7-72
Appendix 2-1 Storm Profile, DPS #7, Feb 7,1972
147
-------
SAL,
Hlg/l
C.O.D.
mg/l
mg/1
pH
9.0
6,0
i=^cm n
~i-—*—.*—.*.
72 96
Time (Min.)
120
Sampler A • Sampler C A
Sampler B O Sampler D D
CHEMICAL PARAMETERS DPS#7
PROFILE 2-7-72
Appendix 2-2 Storm Profile, DPS #7, Feb. 7, 1972
148
-------
10'
10'--
6
o
o
O
O
10
g
W
•H
C
ffl
txO
10
6..
j§ 105
JO
•H
C
113
M 4
S 10
10 3t
^ /
10
10
10
I /
I /
\ I
\ I
I /
I /
6
0 24
48 72 96
Time (Min.)
TOTAL
COLIFORM
Sampler A
Sampler B
Sampler C
Sampler D
FECAL
COLIFORM
120 144
BACTERIAL RESULTS DPS#7
STORM PROFILE 2-7-72
Appendix 2-3 Storm Profile, DPS #7, Feb. 7, 1972
149
-------
H20
PUMP
RATE
cfs
Ci2R
mg/l
NAOCt
FEED
gpm
3000
2000..
1000--
0
2.0
1.6
1.2--
.8"
.4-'
Not Available
60
50-
40-
30.
20-
10-
0
Not Available
40 80 120 160 200 240
Time (Min.)
Sampler A • Sampler C A
Sampler B O Sampler D D
PHYSICAL PARAMETERS DPS #7
STORM PROFILE 3-2-72
Appendix 3-1 Storm Profile, DPS #7, Mar. 2, 1972
150
-------
SAL,
mg/l
C.O.Di
mg/l
mg/l
pH
10000
8000--
6000--
4000--
2000--
4.0-
3.0-
2.O..1
1.0..
0
80 120 160
Time (Min.)
200
Sampler A • Sampler C A
Sampler B O Sampler D D
CHEMICAL PARAMETERS DPS #7
STORM PROFILE 3-2-72
Appendix 3-2 Storm Profile, DPS #7, Mar. 2, 1972
151
-------
E
o
o
H
CO
t—'
£Z
CO
•H
c
re!
bO
rH
s
o
o
to
g
(0
•H
c
(ti
W)
P!
O
10
5-
O0
10 -•
10 +
10 t
f
\
TOTAL
COLIFORM
Sampler A •
Sampler B O
Sampler C A
Sampler D D
FECAL
COLIFORM
40 80 120 160 200 240
Time (Min.)
BACTERIAL RESULTS DPS #7
STORM PROFILE 3-2- 72
Appendix 3-3 Storm Profile Results, DPS #7, Mar.2, 1972
152
-------
H20
PUMP
RATE
cfs
Ci2R
mg/l
NAOCL
FEED
gpm
3000
2000 ..
1000-
0
2.0
1.6--
1.2--
.8"
.4
0
60
50--
HO--
30-.
20-
10--
0 -
Not Available
Not Available
20
60
Time (Min.)
80
100
Sampler A ® Sampler C A
Sampler B O Sampler D P
PHYSICAL PARAMETERS DPS #7
STORM PROFILE 3-9-72
Appendix U-l Storm Profile, DPS #7, Mar. 9, 1972
153
-------
SAL,
aig/l
mg/l
CL2D
mg/l
PH
10000
8000-
eoool
}
4000
2000
0
300
8^
200
100 +
0
9.0
8.0 ••
7.O.-
6.0
D-
-~- --- o
I 1-
20
•4——4-
100
40 60 80
Time (Min.)
Sampler A • Sampler C A
Sampler B O Sampler D D
CHEMICAL PARAMETERS DPS#7
STORM PROFILE 3-9-72
120
Appendix H-2 Storm Profile, DPS #7, Mar. 9, 1972
154
-------
10
G ±U 1
o JD
5 .--
1 io5-
Cfl
•rH i
c
1 "*•
r^x" X -
- o-d V
i1
iu-
io5-
L)._
r-l
6
| 10 3-
w
•H 2
C 10 -
bd
0
lo1-
'•^A*-'""*
.
•O--CX ^-Qr "
"^i \ -
^•^ \ /^-
Vx
— i — i — i__i — i — i — i — i — i — i — i —
TOTAL
COLIFORM
Sampler A •
Sampler B O
Sampler C A
Sampler D D
FECAL
COLIFORM
10 30 50 70 90 110
Time (Min.)
BACTERIAL RESULTS DPS #7
STORM PROFILE 3-9-72
Appendix 4-3 Storm Prpfile Results, DPS #7, Mar. 9, 1972
1'55
-------
H20
PUMP
RATE
cfs
CL2R
mg/1
NAOCL
FEED
gpm
3000
2000 ..
1000--
0
2.0
1.6
1.2
,8
.4
0
60
50
40
30
20
10
0
Note: Pumped 2 hrs prior to
initation of disinfectant
Note: C1?R analyzer
ceased functioning
at t = 60 min
40 60
Time (Min.)
80
110
Sampler A • Sampler C
Sampler B O Sampler D
PHYSICAL PARAMETERS DPS#7
STORM PROFILE 3-19-72
Appendix 5-1 Storm Profile, DPS #7, Mar. 19, 1972
120
156,
-------
SAL,
mg/l
C.O.Di
mg/l
Ci2D
mg/l
pH
10000
9000
8000
7000
6000
5000
4000
3000
2000
1000
0
300
200
100
0
5.0
4.0
3.0
2.0
1.0
0
20
60
Time (Min.)
100
120
Sampler A • Sampler C
Sampler B O Sampler D
CHEMICAL PARAMETERS DPS #7
STORM PROFILE 3-19-72
A
D
Appendix 5-2 Storm Profile, DPS #7, Mar. 19, 1972
157
-------
10
10 7-
i~i n Q
s
o
o
H
^^^
n 1Q5-
•H
c
£ lO4'
o
10 3-
^ w
10 5"
10 4-
^
,— {
s
o
M 10 -
^s,^
to
6
to
•2 10 2-
rd
bO
fn
0
10 X
•-^r^ — ^ — ^-*____— -*
\ \
V
\D V D r
\ \
\ \
V
\ V
\
\ \
\ \
b — °-V,
\
• V-*. ., . — ^
r*C ''^v^r^ •___JL~" ^^
^\n — A-" ^---c
\ \
\ \
\ \
\ \
\ \
\ \
\ \
\ \ ^-°-^
Jr ~
^
1 ! 1 1 1 1— 1 1 1 1 1 , .
]
TOTAL
COLIFORM
Sampler A •
Sampler B O
Sampler C A
Sampler D D
FECAL
COLIFORM
20 40 60 80 120
Time (Min.)
BACTERIAL RESULTS DPS#7
STORM PROFILE 3-19-72
Appendix 5-3 Storm Profile Results, DPS #7, Mair. 19, 1972
158
-------
H20
PUMP
RATE
cfs
Ci2R
mg/1
NAOCt
FEED
gpm
3000
2000 ..
1000-
0
2.0
1.6--
1.2--
.8"
WIA
1*0 80 120 160
Time (Min.)
Sampler A • Sampler C A
Sampler B O Sampler D Q
PHYSICAL PARAMETERS DPS #7
STORM PROFILE 5-11-72
Appendix 6-1 Storm Profile, DPS #7, May 11, 1972
159
-------
SAL,
Elg/l
C.O.Di
mg/l
Ci2D
mg/l
pH
10000
8000-
6000-
4000-
2000 -
0
300
200"
100 •
0
4.0-
3.0-
2.0.
1.0.
0
9.0
8.0 -
7.0 -
6.0
-
-
-
- 4 """---n n
' \
[oo^X^ ^-^j*
«
!
•
|
1 — 1 1 1 — I 1 1 1 1 1 1 1
UO 80 120 160 200
Time (Min.)
Sampler A • Sampler C A
Sampler B O Sampler D D
CHEMICAL PARAMETERS DPS #1
STORM PROFILE 5-11-72
240
Appendix 6-2 Storm Profile, DPS #7, May 11, 1972
160
-------
->-u r
10 7--
H 106-
f~i
O
H
1 io5-
CO
•H
C
rti
w , ~ 4-
f-. 10
0
10 3-
10 5-
10 4-
•
rH
£
0
3 10 3-
"**>•*
to
rt
^
K)
•H 2
C 10 ^
tfl
bO
r
H
O
10 1
^ \
*v, »
• ^ \ -^
V \^ 0
\ \x^ D
v\ /
,'A \ /
X V ^ /
" ^ ^--V
\
V.
ti
^\
\.
v
^
\
\
\
\
°^-*\
Tr \
. \ v^
\\ ^a
\\
\\
\ \
\\
\ \
iV
bA-o----°
A
\
_A
"ti
! I 1 1 1 1 1 1 1 1 r—
TOTAL
COLIFORM
Sampler A •
Sampler B O
Sampler C A
Sampler D d
FECAL
COLIFORM
80 120 160
Time (Min.)
200 -240
BACTERIAL RESULTS DPS #7
STORM PROFILE 5-11-72
Appendix 6^3 Storm Profile Results, DPS #7, May 11, 1972
vv 161
-------
H20
PUMP
RATE
cfs
Ci_2R
mg/l
FEED
gpm
3000
2000..
1000--
0
2.0
1.6
1.2
.4
0
60
50
40
30
20
10
0
80
160 240 380 400 480
Time (Min.)
Sampler A • Sampler C
Sampler B O Sampler D
PHYSICAL PARAMETERS DPS#7
STORM PROFILE 5-12-72
Appendix 7-1 Storm Profile, DPS #7, May 12, 1972
162
-------
SAL,
ag/l
CL2D
mg/l
PH
J-U U UU
8000-
6000-
4000-
2000-
_
0
300
200'
100-
0
3.0-
2.0.
1.0.
0
9.0
8.0-
7.0 -
6.0
-
i
r
'.
!
-
i
'
!
80 120 240 320 400 48
Time (Min.)
Sampler A • Sampler C
Sampler B O Sampler D
CHEMICAL PARAMETERS DPS#7
STORM PROFILE 5-12-72
Appendix 7-2 Storm Profile, DPS #7, May 12, 1972
163
-------
10
10 7-
H 10 &\
0
o
H.
| 10 5-
co
•H
C
1 10*
o
S
A
V ^ — \
V>A \ ^
V o ^
"•^cf &
I v^^ '
O-^-/ ) ^^^^ '
\ "^& X
i T /
\ \ 1
\ \ i
^ y
10 4
T
10 ^
0
s
o
3 io3-
w
6
w
•H o
c 102-
d
o
1
10 -
. .
s
^\ ^^^v
\
VI K
fV / '^
\ ^^ I
\ ^ a
\ ^\AX*
-o
1 ! 1 1 1 A ! 1 1 1 1
TOTAL
COL i FORM
Sampler A €J
Sampler B O
Sampler C A
Sampler D E
FECAL
COLIFORM
80 160 240 320 400 480
Time (Min,)
BACTERIAL RESULTS DPS #7
STORM PROFILE 5-12-72
Appendix 7-3 Storm Profile Results, DPS #7, May 12, 1972
164
-------
H20
PUMP
RATE
cfs
Ci_2R
mg/l
NAOCL
FEED
gpm
3000
2000..
1000--
0
2.0
1.6
X.2
.8'-
0
60
50-
40--
30-.
20
40 60
Time (Min.)
100
120
Sampler A • Sampler C A
Sampler B O Sampler D O
PHYSICAL PARAMETERS DPS #7
STORM PROFILE 6-9-72
Appendix 8-1 Storm Profile, DPS #7, June 9, 1972
165
-------
SAL,
mg/l
C.O.D.
mg/l
mg/1
pH
10000
8000-
6000-
4000-
2000-
0'
300
200'
100 •
0
4.0-
3.0-
2.0.
1.0.
0
9.0
8.0 -
7.0.
6.0
' V
; \
:^t^^
^^~-—+
^^
^^^~*-&-"(* — •
20 40 60 80
Time (Min.)
Sampler A • Sampler C A
Sampler B O Sampler D D
CHEMICAL PARAMETERS DPS #7
STORM PROFILE 6-9-72
Appendix 8-2 Storm Profile, DPS #7, June 9, 1972
166
-------
10
o
o
•H
c
rt
fc
o
6
o
o
rH
6
CO
•H
fi
bO
4..
10
103T
V
/\
- J
10
10
5..
io
3..
10-
10
1..
20 40 60 80
Time (Min.)
BACTERIAL RESULTS DPS #7
STORM PROFILE 6-9-72
TOTAL
COLIFORM
Sampler A •
Sampler B O
Sampler C A
Sampler D O
FECAL
COLIFORM
Appendix 8-3 Storm Profile Results, DPS #7, June 9, 1972
167
-------
H20
PUMP
RATE
cfs
Ci_2R
mg/l
FEED
gpm
3000
2000 ..
1000--
100 150
Time (Min.)
200
250
300
Sampler A • Sampler C A
Sampler B O Sampler D P
PHYSICAL PARAMETERS DPS#7
STORM PROFILE 7-5-72
Appendix 9-1 Storm Profile, DPS #7, July 5, 1972
168
-------
SAL,
mg/l
C.O.D.
mg/l
CL2D
mg/l
pH
.LUUUU
8000-
6000-
4000-
2000-
0
300
200'
100-
0
4.0-
3.0-
2.0.
1.0.
0
9.0
8.0-
7.0 -
6.0
,
\
\
\
\
iSrt!)*- .d-vA /^A T™1 "^A f\_/\ nv*v -j\' i/h n — W
N
•s.
1 ^ — 4 1 1 1 1 1 1 1^ H- —
50 ' 100 150 200 250
Time (Min.)
Sampler A « Sampler C A
Sampler B O Sampler D D
CHEMICAL PARAMETERS DPS#7
STORM PROFILE 7-5-72
300
Appendix 9-2 Storm Profile, DPS #7, July 5, 1972
169
-------
ID
io7-
H io6-
o
o
Organisms/
M I-1
0 0
-P en
io3-
1C5'
r-ganisms/lOOml.
(_. (_i !_•
0 0 O
ro co -P
*H
0
101
9
i
_ i
60 ^^D^ "$^Q
- V-" ]\
"A\ / x
v /
^"4
-
0
•>• .
?\ NSXD^"'~R / \
!.'\^-^ ;x \ \
*n ^ \/ \
^'\/\ ^
\/ > \
» WJ ^
——) 1 ^ 1- 1 1 1 1 1— — 1 _!___
TOTAL
COLIFORM
Sampler A •
Sampler B O
O ^ rm-\ T ^v^ C^ ^\
bampxer o o
Sampler D E
FECAL
COLIFORM
50 100 150 200 250 300
Time (Min.)
BACTERIAL RESULTS DPS#7
STORM PROFILE 7-5-72
Appendix 9-3 Storm Profile Results, DPS #7, July 5, 1972
•170
-------
3000
H20
PUMP
RATE
cfs
CL2R
mg/1
NAOCL
FEED
gpm
2000.
1000-
0
9.n
1.6-
1.2-
.8'
.4-
0
60
50-
40-
30-
20-
10-
0
i
1 / VS/S*1 fsAAAV^J
' \ r u ' M^^x
\/
fa
•r^^
1 1 1 1 1 1 1 ' — 1 H- — f -+-
80 120
Time (Min.)
160
Sampler A • Sampler C
Sampler B O Sampler D
PHYSICAL PARAMETERS DPS #7
STORM PROFILE 7-12-72
D
Appendix 10-1 Storm Profile, DPS #7, July 12, 1972
171
-------
SAL.
mg/l
C.O.D,
mg/l
CL2D
mg/l
pH
10000
8000-
_,
6000-
4000-
2000-
0
300
200'
100-
0
4.0-
3.0-
2.0.
1.0.
0
9.0
8.0 "
7.0 .
6.0
-
[
; D— •- D
\ - |
1
.
' ^^tfe^.-^._^-..-^A---A
•gj* --o--'Qo----
-------
J.U
10 '•
6
e 10 "
o
o
rH
CO
•ri
c
Tj
bO L|,
O
3
10 '
5
10
10 ^
•
i— i
E
o
o -3
rH 10 -
W
CO
•H 2
C 10 -
bO
J_J
0
10 X-
'
1
• \\
_ V\:^-'^~'-0
\ \
\ \
\ \ .
b-'^^--^'
X3
^fi
TS Q
• \ , \ D
\ ^ .s^
1 , \ \ /
1 \ \ \
A\if \ a/'
\ \ ND
'. \
\ \
V ^
\o
\ \
\ \
\ \
\ \
K--^b--OA-Q^ ^
— 1 — 1 — 1 — 1 — 1 — i — 1 — 1 — 1 — II -
TOTAL
COLIFORM
Sampler A •
Sampler B O
Sampler C A
Sampler D O
FECAL
COLIFORM
Time (Min.)
BACTERIAL RESULTS DPS #7
STORM PROFILE 7-12-72
Appendix 10-3 Storm Profile Results, DPS #7, July 12, 1972
-------
H20
PUMP
RATE
cfs
Ci2R
mg/l
NAOCL
FEED
gpm
3000
2000
1000 -•
50
40
30
20
10
0
80 120
Time (Min.)
160
200
240
Sampler A • Sampler C A
Sampler B O Sampler D D
PHYSICAL PARAMETERS DPS#7
STORM PROFILE 7-13-72
Appendix 11-1 Storm Profile, DPS #7 July 13, 1972
174
-------
SAL,
mg/l
CL2D
mg/l
pH
10000
8000
6000
4000
2000--
0
300
C.O.D, 20°
100 +
0
4.04-
3.0
2.0
1.0
0
9.0
8.0
7.0
6.0
i
80 120 160
Time (Min.)
200
240
Sampler A • Sampler C
Sampler B O Sampler D
CHEMICAL PARAMETERS DPS#7
STORM PROFILE 7-13-72
Appendix 11-2 Storm Profi.le, DPS #7, July 13, 1972
175
A
D
-------
1U
7
10 -
i 10 6-
o
0
H
u 10 5-
w
••H
c
rd
W3 „ 4.
fc 10
o
io3-
10 5-
4
10 -
•
r— 1
0
O , „ Q
rH 10 3-
co
w
•H ?
c 10 -
bO
O
10 x-
( ^- "" *"* **
\ r~[f^f ^ij
®(
"K
i Y
-1 \
1 i
1 \
' \
" 6--O. \
X \
\ ,
sl ,O
p-' \
r \
\ v
\ \
^rJO^
| '
1 /
1 /
"^c> ^~^d
\ V
\\
\A
\,
\
\
- 1 1 -4 4- \r~ 1 J -1 ( 1 1
TOTAL
COLIFORM
Sampler A •
Sampler B O
Sampler C A
Sampler D D
FECAL
COLIFORM
40 80 120 160
Time (Min.)
200 240
BACTERIAL RESULTS DPS #1
STORM PROFILE 7-13-72
Appendix 11-3 Storm Profile Results, DPS #7, July 13, 1972
176
-------
3000
H20
PUMP
RATE
cfs
Ci_2R
mg/l
NAOCL
FEED
gpm
2000..
1000-
o
2.0
1.6
1.2
.8
.4
0
60
50
40
30
20
10
0
50 100 150
Time (Min.)
200
250
Sampler A • Sampler C
Sampler B O Sampler D
PHYSICAL PARAMETERS DPS #7
STORM PROFILE 7-20-72
A
D
Appendix 12-1 Storm Profile, DPS #7, July 20, 1972
177
-------
SAL,
mg/l
C.O.D,
mg/l
CL2D
mg/l
pH
1UUUU
8000-
6000-
.•
4000-
2000-
0
300
200'
100-
0
4.0-
3.0-
2.0.
1.0.
0
9.0
8.0-
7.0.
6.0
. ^"-^D
\
\
\
X,
\
0 ^^r~^^-^t--^ "^^
•
^o^-:-^^^ o
•• — h 1 —
-------
1U
io7-
* c
H 10 -
O
o
iH
1 io5-
10
•H
C
(d
u.n 1 1
dU H.
& 10
o
io3-
5
10
4
10 '
inisms/lOOml
j_i |_.
O O
ro so
*u
bS
k
O
1
10"
«
7^ X
; \ /\
\\ ' \
* \\ / ^
i \\ / \
1 >\ / \
4 L/ ^
D— "\\
\
' \
\\
' ^
V \J
\
\A
9-9 •
i \
. l \
A 4 n
V\ A
' \ i \
v / \
* \ i \
-r \
\\ \
\k \
\x \
\ \ V
k-d>A--^ a
ra_4_^_^__^_™-H"~4-^r--4-^^
TOTAL
COLIFORM
Sampler A •
Sampler B O
C-aTnt-iT a~f\ P A.
oa.inpxer' u w
Sampler D D
FECAL
COLIFORM
To 100 150 200 250
Time (Min.)
BACTERIAL RESULTS DPS#7
STORM PROFILE 7-20-72
Appendix 12-3 Storm Profile Results, DPS #7, July 20, 1972
179
-------
H20
PUMP
RATE
cf s
Ci2R
mg/l
FEED
3000
2000 ..
1000--
MO 60
Time (Min.)
80
100
120
Sampler A ® Sampler C A
Sampler B O Sampler D Q
PHYSICAL PARAMETERS DPS#7
STORM PROFILE 9-30-72
Appendix 13-1 Storm Profile, DPS #7, Sept. 30 , 1972
180
-------
SAL,
mg/l
C.O.D,
mg/l
CL2D
mg/l
pH
xuuuu
8000-
6000-
4000-
2000-
0
300
200'
100-
0
4.0-
3.0-
2.0.
1.0.
0
9.0
8.0-
7.0 .
6.0
LJ ' U
11,000 11,800
- ^^a^^^-^---^— -»• A
-— _-
/\
•^N/ ^^
^^—•^
Ct. J3~ ~~ O— O
20 40 60 80 100 12
Time (Min.)
Sampler A * Sampler C A
Sampler B O Sampler D D
CHEMICAL PARAMETERS DPS #7
STORM PROFILE 9-30-72
Appendix 13-2 Storm Profile, DPS #7, Sept. 30, 1972
181
-------
10
7
10 -
g
H 10-
O
o
H
co 1Q5.
M
•H
C
£T u
h 10
o
3
10 •
10 "
H
6
o
S io3-
6
w
•H o
S 10-
rd
bO
fn
O
1
10 •
*V\
V -, A
\
- i \
\^ .
' » X
' \ x
-d \ V
\ \
\ 'V P
\ V /
\ \ /
\ N /
\ ^ /
\ N '
\
\
V
' 1 1 \- — 1 1 1 1 1 1 II
TOTAL
COLIFORM
Sampler A •
Sampler B O
Sampler C A
Sampler D Q
FECAL
COLIFORM
20 40 60 80 100 120
Time (Min.)
BACTERIAL RESULTS DPS #7
STORM PROFILE 9-30-72
Appendix 13-3 Storm Profile Results, DPS #7, Sept. 30, 1972
182
-------
H20
PUMP
RATE
cfs
CL2R
mg/l
NAOCL
FEED
gpm
3000
2000..
1000-
0
2.0 _
1.6-
1.2-.
.8"
.«*"
o L
60 -
50-
UO.-
30..
20-"
10"
0 .
-t-
50 100 150
Time (Min.)
200
250
300
Sampler A • Sampler C A
Sampler B O Sampler D Q
PHYSICAL PARAMETERS DPS#7
STORM PROFILE 10-22-72
Appendix 14-1 Storm Profile, DPS #7, Oct. 22, 1972
183
-------
SAL,
mg/l
C.O.D,
mg/l
CL2D
mg/l
pH
10000
8000-
6000-
4000-
2000-
0
300
200'
100-
0
4.0-
3.0-
2.0.
l.Oj
0
9.0
8.0 -
7.0 -
6.0
- s,
V.
"\
• \
\
- \
\
t^WV^-^A <*~* *— ^-^
^
^~*
^V_ ^^\
&•'' ~ ,-^^ s& A
00^*
50 100 150 200 250 300
Time (Min.)
Sampler A • Sampler C A
Sampler B O Sampler D D
CHEMICAL PARAMETERS DPS#7
STORM PROFILE 10-22-72
Appendix 14-2 Storm Profile, DPS #7, Oct. 22, 1972
-------
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6
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O
o
rH
1 io5-
CO
•H
C
nj
P? 10 '
0
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10
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WJ
0
10 -1-
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\ 1
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\ 1
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> 1
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1 ; \-—* 1 . .1 •! 1 ! \ — -4—
TOTAL
COLIFORM
Sampler A •
Sampler B O
Sampler C A
Sampler D O
FECAL
COLIFORM
50 ' 100 ' 150200 250 300
Time (Min.)
BACTERIAL RESULTS DPS#7
STORM PROFILE 10-22-72
Appendix 14-3 Storm Profile Results, DPS #7, Oct. 22, 1972
185
-------
U 0
r,2G
PUMP
RATE
cfs
mg/l
FEED
3000
2000*
1000-f
60
50'
40.
301
20|
10-1
0
H h
12 24 '36
Time (Min.)
Sampler A •
Sampler B O
PHYSICAL PARAMETERS DPS
STORM PROFILE 11-472
60
Sampler C
Sampler D
72
Q
Appendix 15-1 Storm Profile, DPS #7, Nov. 4, 1972
186
-------
SAL,
rag/I
10000
80004-
600d|
4000
2000
12
24 36 48
Time (Min.)
60
C.O.Di
mg/l'
CL2D
mg/l
_ ( !
Pn
0
Q n fi
200'
100 i
0
4.0-
3.0-
2.0.
1.0.
0
9n
. U
3.0-
7 n
6.0
s V ^^^ '-'= ~— • --O- • —-.~-. — —— ^ V
! .
*"
•
-
SJ—'j-Ji ^. J-v^ -fi
w
1 ! 1 1 1 ! !- — — i ( — 1— — H —
72
Sampler A • Sampler C A
Sampler B O Sampler D D
CHEMICAL PARAMETERS DPS #7
STORM PROFILE 11-4-72
Appendix 15-2 Storm Profile, DPS #7, Nov. 1, 1972
187
-------
•*•
7
10 j
H IQ6-
s
0
o
H
, V
6 D
\N
O \
\ xv
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2 KPT x \
S \ \
w \ x.
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C ! \
re! \
TOTAL
COLIFORM
bo 4J. h
fc 10
o
io3-
, .5-
10 1
H
H
e
0
S 10 3-
"^^
w
S
w
S lo1
bJD
fn
O
10 ^
^
\
\
\
\ ^Q
V"'" \
\
\
\
\
\
n
•^ *
P
- ^
\ s.
\ X.
\ Vs
\ V
\ N^
^\
^
\
"o o
1 1 1 1 1 1 — 1 1 1 1 1 —
Sampler A , •
Sampler B O
Sampler C A
Sampler D O
FECAL
COLIFORM
12 24 36 48 60 72
Time (Min.)
BACTERIAL RESULTS DPS #7
STORM PROFILE 11-4-72
Appendix 15-3 Storm Profile Results, DPS #7, Nov. 4, 1972
188
*U.S GOVERNMENT PRINTING OFFICE:1973 546-312/158 1-3
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SELECTED WATER i. Rfi*r»f
RESOURCES ABSTRACTS ...
INPUT TRANSACTION FORM *•
4 Title HYPOCHLORINATION OF POLLUTED STORM WATER 5 *.perf/;.,e
PUMPAGE AT NEW ORLEANS, *
S. i form, , Org.; ..attoo
I Sepo: Nu.
f. Au<:hor(f.)
Pontius, U.R., Pavia, E.H., and Crowder, D.G.
11023 FAS
.
Pavia-Byrne Engineering Corporation
431 Gravier St.
New Orleans, La. 70130 '/ Typ, i Repu . and
Pfioa Co ered
12. Si nsorin Organ ition
Environmental Protection Agency report number,
EPA-670/2-73-067, September 1973.
ct storm water from the streets of New Orleans flows to large
drainage pumping stations where it is discharged into Lake Pontchartrain
by means of long outfall canals. To reduce the coliform density, storm
water was disinfected with sodium hypochlorite (NaOCl). Project facili-
ties included manufacture, transportation, storage and feeding of 100
?am/l NaOCl. Residual chlorine analyzers were used to monitor NaOCl
dosage levels. Sixteen high volume storms totaling 10 to the 9th power
gal. of storm water were treated with more than 35,000 gal. of NaOCl.
"otal and fecal coliform in untreated storm water exceeded 1000 org/100 ml
99% of the time. Coliform densities in treated water were significantly
reduced, with chlorine residuals (total available) of greater than 0.5
mg/1 resulting in 99.99% or greater removal. However, rapid recovery of
coliform levels occurred within 24 hours. Total coliform recovered to
pre-disinfection levels, but fecals did not. The recovery did not appear
to be the result of tidal influences. Long term fecal coliform levels
were reduced by one order of magnitude in each outfall canal. The
amortized cost of NaOCl manufacturing, transporting, feeding and control
facilities was $53,600/yr. NaOCl costs for treating 5 times 10 to the
10th power gal. of storm water yearly were $200,300. This resulted in a
treatment cost of $.000051/gal.
i?a. Descriptors *Disinfection, *Chlorination, *Water Pollution Treatment,
treatment Facilities, *Storm Runoff, Coliforms, Operation and Maintenance
Plastic Pipes, Oxidation-Reduction Potentials, Centrifugal Pumps,
Concrete Lined Canals, Protective Coatings, Sodium Compounds, Storage
Tanks
17b. Identifiers
*Hypochlorination, *Sodium Hypochlorite Manufacturing Facilities, *Lined
Steel Storage Tanks, *New Orleans, Hypochlorite Feeding Facilities,
Residual Chlorine Analyzers
COWRR Field & Groun Q5F
/• vi'-ibilitv • 19. Security Class.
"Repot }
•a S*. 'ityC' s.
(Piee)
ZL No. of
Pages
». Pi. •!
Send To:
WATER RESOURCES SCIENTIFIC INFORMATION CENTER
US. DEPARTMENT OF THE INTERIOR
WASHINGTON. D. C. 2O24O
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