&EPA
United Slates
Environmental Protection
Agency
Municipal Environmental Research
Laboratory
Cincinnati OH 45268
EPA 600 2-80-010
June 1980
Research and Development
Benefits of
Maintaining a
Chlorine Residual in
Water Supply
Systems
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. Special Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental 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.
This document is available to the public through the Nationa Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-80-010
June 1980
BENEFITS OF MAINTAINING A CHLORINE RESIDUAL
IN WATER SUPPLY SYSTEMS
by
Michael C. Snead
Vincent P. Olivieri
Cornelius W. Kruse"
Kazuyoshi Kawata
The Johns Hopkins University
School of Hygiene and Public Health
Division of Environmental Health Engineering
Baltimore, Maryland 21205
Grant No. R804307
Project Officer
Martin J. Allen
Drinking Water Research Division
Municipal Environmental Research Laboratory
Cincinnati, Ohio 45268
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewed by the Municipal Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publica-
tion. Approval does not signify that the contents necessarily reflect the
views and policies of the U.S. Environmental Protection Agency, nor does
mention of trade names or commercial products constitute endorsement or
recommendation for use.
ii
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FOREWORD
The Environmental Protection Agency was created because of increasing
public and government concern about the dangers of pollution to the health
and welfare of the American people. Noxious air, foul water, and spoiled
land are tragic testimony to the deterioration of our natural environment.
The complexity of that environment and the interplay between its components
require a concentrated and integrated attack on the problem.
Research and development is that necessary first step in problem solu-
tion and it involves defining the problem, measuring its impact, and search-
ing for solutions. The Municipal Environmental Research Laboratory develops
new and improved technology and systems for the prevention, treatment, and
management of wastewater and solid and hazardous waste pollutant discharges
from municipal and community sources, for the preservation and treatment of
public drinking water supplies, and to minimize the adverse economic, social,
health, and aesthetic effects of pollution. This publication is one of the
products of that research; a most vital communications link between the re-
searcher and the user community.
This report evaluates the effectiveness of chlorine In water distribu-
tion systems in inactivating microorganisms introduced by posttreatment
contamination. The relationship of chlorine residual, turbidity, pH, and
temperature to levels of bacteria found on plate count agar, and biochemical
characteristics of these bacteria are presented for samples from the Balti-
more., Maryland and Frederick, Maryland water distribution systems.
Francis T. Mayo, Director
Municipal Environmental Research
Laboratory
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ABSTRACT
The protection afforded the water consumer by the maintenance of a chlo-
rine residual in water distribution systems was evaluated in laboratory hold-
ing tanks and reservoirs and existing municipal water distribution systems.
In the laboratory studies, tap water, adjusted to the appropriate p 11 , temper-
ature and chlorine residual, was challenged with varying levels of autoclaved
sewage seeded with Shigella sonnei, Salmonella typhimuriurn, coliform orga-
nisms (IMVIC -H-), poliovirus 1, and f2 bacterial virus. Comparative sur-
vivals of these microorganisms were evaluated over two hour periods. As
expected, microbial inactivation was increased by lower pH, higher tempera-
ture, higher initial chlorine concentration, and lower sewage concentration.
An initial free chlorine residual was more effective than an equivalent
initial combined chlorine residual. Generally, S. sonnei, S. typhimurium
and coliform organisms were inactivated at the same rate but poliovirus 1
was more resistant and f2 was the most resistant. At pH 8, with an initial
free chlorine residual of 0.7 mg/liter, and sewage added to levels of up to
1% by volume, 3 logs or greater bacterial inactivation was obtained within
60 minutes. Viral inactivation under these conditions was less than 2 logs.
In reservoir studies, where the residual chlorine is replenished by inf low
of fresh uncontaminated chlorinated tap water, greater inactivation was
observed at the higher sewage concentration levels tested. 986 samples were
collected from the Baltimore (850) and Frederick (136) water distribution
systems and assayed for coliforms. Standard plate counts, 35°C plate at 4
days (PC 4) and 20°C plate at 9 days (PC 9) were made and turbidity, pH,
temperature and chlorine residual measurements were taken. Coliforas were
rarely found in the Baltimore system and infrequently recovered from the
Frederick system. Significant positive correlation (> 95% level) were ob-
served in both water systems for PC 4 and PC 9 versus turbidity and tempera-
ture. Significant negative correlation (> 95% level) were observed for PC
4 and PC 9 versus chlorine residual. The maintenance of a free chlorine re-
sidual was found to be the single most effective measure for maintaining a
low plate count in the distribution system. More than 6000 isolates from
the 20°C and 35°C plate counts were further studied and classified into 43
functional groups based on seven biochemical characteristics. Eight groups
made up 76% of the observed microorganisms. Although the frequency of isola-
tion and level of these groups was variable from sample to sample and station
to station, only few groups of microorganisms predominated at each of the
incubation temperatures and in each of the distribution systems.
This report was submitted in fulfillment of grant No. R804307 by the
Johns Hopkins University under the sponsorship of the U.S. Environmental Pro-
tection Agency. This report covers the period July 1, 1976, to June 30,
1979, and work completed as of January 31, 1979.
iv
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CONTENTS
Foreword iii
Abstract iv
Figures vii
Tables xi
Acknowledgment xiii
1. Introduction 1
2. Conclusions 5
3. Recommendations 6
4. Description of Studies 7
Holding Tank 7
Reservoir 7
Municipal Distribution System 7
5. Methods 11
Holding Tank Studies 11
Contamination Evaluation 11
Isolation and Enumeration of Bacteria 11
Preparation and Enumeration of Viruses 14
Experimental Procedures 14
Reservoir Studies 17
Experimental Procedures 17
Municipal Distribution System 18
Sample Collection and Analysis 18
Microbial Differentiation 20
6. Results 24
Holding Tank Studies 24
Contaminant Evaluation 24
Microbial Survival 27
Chlorine Residual 31
Extended Time Studies 37
Reservoir Studies 37
Municipal Distribution System 40
Microbiological Aspects 40
7. Discussion 89
Holding Tank Studies 89
SImulated Contaminant 89
Mixing and Flow Regimen 89
Microbial Inactivation 90
Municipal Distribution Systems 92
Microbiological Quality 94
Microbial Diffe ntiation 99
V
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CONTENTS (continued)
References . 102
Appendices 107
A. Holding tank data 107
B. Extended time data 123
C. Reservoir data 138
D. Municipal distribution system data 142
E. Major biochemical groups 167
vi
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FIGURES
Number Page
1 Major elements of the Baltimore, Maryland water
treatment and distribution system 8
2 Schematic holding tank experimental protocol 15
3 Calibration curve for the determination of fluorescein
concentration 19
4 Effect of sample collection and refilling on the
concentration of fluorescein dye in the reservoir
studies 19
5 Free chlorine residual determination by sample
collector with DPD versus tree chlorine deter-
mination by amperometric titration 21
6 Effect of storage at 4°C on selected chemical
parameters for raw sewage and autoclaved raw
sewage 25
7 Effect of storage at 4°C on the chlorine break-
point curve for autoclaved raw sewage 26
8 Effect of storage at 4°C on the chlorine break-
point curve for raw sewage 26
9 Concentrationtime relationship for 90% inactivation
of test bacteria, on the basis of the initial
chlorine residual 28
10 Inactivation of the coliform, f2 and polio 1 by an
approximate initial chlorine residual of 1 mgI
liter in the presence of 1, 5, and 10% sewage
at pH 8.0 29
11 Inactivation of the coliform, f2 and polio
1 by an approximate initial chlorine residual
of 1 mg/liter in the presence of 1, 5 and 10%
sewage at pH 6. 0 30
vii
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FIGURES (continued)
Number Page
12 Inactivation of the coliform and f2 in the presence
of 0.17% sewage with an approximate initial chlorine
residual of 0.3 mg/liter at pH 6.0 and 8.0 32
13 Inactivation of the coliform, f2 and polio 1
by an approximate initial free chlorine residual
of 1 mg/liter in the presence of 1 to 10%
sewage at p11 6.0 and 8.0 33
14 Inactivation of the coliform, f2 and polio 1
by an approximate initial combined chlorine re
sidual of 1 mg/liter in the presence of 1, 5,
and 10% sewage at pH 6.0 and 8.0 34
15 Effect of pH on the inactivation of the coliform,
f2 and polio 1 35
16 Effect of long term storage on the level of the
coliform in sewagetap water mixtures 39
17 Inactivation of natural populations of coliforms
and seeded £2 virus contained in sewage after
addition to tap water in the reservoir with 0.38
to 0.52 mg/liter free chlorine at pH 8.0 to 8.4 41
18 Inactivation of natural populations of coliforms
and seeded f2 virus contained in sewage after addition
to tap water in the reservoir with 1.50 mg/liter com-
bined chlorine at pH 8.2 to 8.4 43
19 Inactivation of natural populations of coliforms
and seeded 12 virus contained in sewage after
addition to tap water, 1:1 tap and river water
mixture, and river water in the reservoir with
1.21.3 mg/liter combined chlorine at pH 8.0 45
20 Effect of incubation time on the number of bacterial
colonies obtained on standard plate count agar
at 20°C and 35°C 48
21 Scattergram log 35°C plate count, 4 day incubation
versus free chlorine, Baltimore 51
22 Scattergram log 20°C plate count, 9 day incubation
verus free chlorine, Baltimore 52
23 Scattergram log 35°C plate count, 4 day incubation
versus turbidity, Baltimore 53
viii
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FIGURES (continued)
Number Page
24 Scattergram log 20°C plate count, 9 day incubation
versus turbidity, Baltimore 54
25 Scattergram turbidity versus free chlorine,
Baltimore 56
26 Scattergram log 35°C plate count, 4 day in-
cubation versus log 20°C plate count, 9 day
incubation, Baltimore 57
27 Relationship between the mean log 35°C plate
count, 4 day incubation and free chlorine re
sidual, Baltimore 58
28 Relationship between the mean log 20°C plate
count, 9 day incubation and free chlorine re
sidua l,Baltirnore 59
29 Relationship between the mean log 35°C plate count,
4 day incubation and turbidity, Baltimore 63
30 Relationship between the mean log 20°C plate
count, 9 day incubation and turbidity,
Baltimore 64
31 Relationship between the mean log 35° plate
count, 4 day incubation and turbidity,
Frederick 69
32 Relationship between the mean log 20°C plate
count, 9 day incubation and turbidity,
Frederick . 70
33 Relationship between the mean log 35°C plate
count, 4 day incubation, and the free fraction
and the total chlorine residual, Frederick 71
34 Relationship between the mean log 20°C plate
count, 9 day incubation, and the free fraction
and the total chlorine residual, Frederick 72
35 Relative occurrence of the different bio
chemical groups at station 1 80
36 Relative occurrence of the different biochemical
groups at station 4 81
ix
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FIGURES (continued)
Number Page
37 Relative occurrence of the different biochemical
groupsatstation27 82
38 Relative occurrence of the different biochemical
groups at station 34 83
39 Relative occurrence of the different biochemical
groups at station 37 84
40 Relative occurrence of the different biochemical
groups at station 43 85
41 Relative occurrence of the different biochemical
groups at station 44 86
42 Relative occurrence of the different biochemical
groups at station 48 87
43 Influence of free chlorine residual on mean log
plate counts . . . . 98
44 Influence of turbidity on mean log plate
counts .... 100
z
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TABLES
Table Page
1 Average Monthly Free Chlorine Residual for
Sampling Stations 10
2 Comparison of TYE and XL Media for the
Enumeration of coliform, S. typhimurium and
S. sor3nei 13
3 Percent Autoclaved Raw Sewage Added to Tap
Water For Each of the Experimental
Conditions 16
4 Comparison of the Toothpick Replicator with
Conventional Tube Methods for Biochemical
Tests 22
5 Mean Chlorine Concentration After Addition
of Varying Amounts of Sewage at pH 6 and 8 36
6 Chlorine Residual Concentrations After Sewage
Addition, as Percent of the Initial Chlorine
Concentration .... 38
7 Chemical Data After the Addition of Raw
Sewage to Tap Water with Free Chlorine 42
8 Chemical Data After the Addition of Raw
Sewage to Tap Water with Combined Chlorine . 44
9 Chemical Data After the Addition of Raw
Sewage to Tap Water, a 1:1 Mixture of Tap
and River Water, and River Water with
Combined Chlorine 46
10 Correlation Coefficient Matrix for Chemical,
Physical and Biological Data Collected in the
Baltimore Water Distribution System 50
11 Distribution of Ranges of Plate Count Values
After 4 day Incubation at 35°C for Varying
Ranges of Free Chlorine Residual 60
xi
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TABLES (continued)
Table Page
12 Distribution of Ranges of Plate Count Values
After 9 day Incubation at 20°C for Varying
Ranges of Free Chlorine Residual 61
13 Multiple Linear Regression Model for the 35°C,
4 Day Plate Count 65
14 Multiple Linear Regression Model for the 20°C, 9
Day Plate Count . . . . . . . . . . . . . . . 66
15 Correlation Coefficient Matrix for Chemical,
Physical and Biological Data Collected in the
Frederick Water Distribution System . .. 68
16 Major Biochemical Groups Isolated from Plate
Counts from the Baltimore and Frederick Nd.
WaterDistributionSystems 74
17 Estimated Pathogen Intake by Water Consumers 93
18 Recommended or Reported Incubation Temperature
and Time for Bacterial Plate Counts in
Water . . . . . 95
xii
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ACKNOWLEDGMENTS
The cooperation of the Water Division of the city of Baltimore
Bureau of Operations for background information and data on the Baltimore
water distribution system is acknowledged. We are particularly indebted
to Mr. Jerry Valcik, plant superintendent, Montebello Water Treatment plant
for providing maps, and information on the sampling stations andMr. John
Hohinan for collecting samples.
We gratefully acknowledge George Smith for providing information and
data on the Frederick, Maryland distribution system.
We acknowledge the assistance of Dr. James A. Tonascia and Dr. Charles
A. Rohde of the Department of Biostatistics for assistance in the data anal-
ysis and Ms. Mary Yurachek for assistance in computer analysis.
The cooperation of George Cunningham, and the staff of Facilities En-
gineering at Fort George G. Meade is also gratefully acknowledged.
xiii
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SECTION 1
INTRODUCTION
The construction of piped water supplies for communities across the
United States was a phenomenal achievement of the 20th century. Compared
to Europe the waterworks in the United States got a slow start, records show-
ing a total of only 243 works by 1875. Only two of these 243 waterworks were
slow sand filtration plants, an almost universal practice abroad for surface
water sources. In the U.S. early systems were untreated upland springs,
impoundments and a large number of well supplies. The number of systems by
1895 increased by one order of magnitude to about 3000. Records were not
precise and the rate of construction was quite rapid at 1000 per year.
The slow sand filter performed well on the less turbid surface sources
generally found in the northeastern cities. For the big rivers such as the
Ohio and Mississippi the filters could not function without pretreatment.
After initial failure the mechanical or rapid sand filtration plant was
made reliable primarily by improved coagulation and backwashing technology.
By the turn of the century only one third of the total population was
served by public water systems of which less than 2 million persons consumed
filtered surface water. By then, 80 percent were of the rapid sand type.
Public water quality was not good and the liability for disease contracted
from these systems was frequent and both municipal and private corporations
were held responsible. Regulation regarding water quality was somewhat
improved by insisting on protected watersheds and ground water sources,
smaller cities and towns had outgrown their supplies and often went to the
nearest river or lake without satisfactory treatment. Waterborne disease
conditions were such that the USPHS began active interest in typhoid fever
spread from the great interstate rivers. Their findings were incorporated
into standards and with the implementation by the states waterborne diseases
began to abate. It was not however, until the introduction of disinfection
with chlorine in 1908, the practice of which spread very rapidly through
all the states on order of boards of health, that public water systems were
no longer important in the spread of typhoid. It was estimated that by
1924, 37,000,000 persons were protected by chlorination in some 3000 cities
and towns. Control of early chlorination practice was based on the dose of
chlorine applied. Recommendations for dosage levels for filtered water
were 0.6 1.2 mg/liter (Foiwell, 1917), 0.20 to 0.25 mg/liter (Turneaure
and Russell, 1924), and 0.24 to 0.96 mg/liter (Waterman, 1934). In 1917,
Folwell stated that the only safe rule is to test the germicidal effect of
different doses on the water in question. Wolman and Enslow (1919) advo-
cated dosage based on chlorine demand of water determined at 5 minutes at
20°C. The dose was chlorine demand plus 0.2 mg/liter. The maintenance
of a chlorine residual throughout a water distribution system was specif 1
1
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cally not recommended, because of alleged problems with unpleasant taste
and odor. When excess prechiorination was used for algae destruction
(because of a polluted water source) very high levels of chlorine were
required and dechlorination was advocated before release of the water to
the distribution system. The practice of heavy prechiorination was con-
sidered wasteful and was not widely practiced in the U.S. Double or multi-
ple chlorination pre and post filtration was quite common in the early
1930s, however, unpleasant tastes and odors were of concern since dosage
rarely if ever exceeded breakpoint.
In an effort to solve chiorotaste problems disinfection with a mixture
of chlorine and ammonia sometimes was successful mainly because the dosage
of chlorine required for demand plus 0.2 ppm residual for 10 minutes was
very low. As advocates of the method were quick to point out, the chlorine
residual resulting after the chlorammoniation process was also more stable.
Since the chlorine residual was stable, did not produce complaints of
taste and odor, and reduced bacterial aftergrowth that occured in the
distribution system (Baylis, 1935), the process became widely acceptable
and the purposeful maintenance of a chlorine residual throughout all or
part of the distribution system was first initiated. The 1941 American
Water Works Association Water Quality and Treatment manual provides the
following statements on the chlorineammonia treatment:
As a means of eliminating tastes and odors caused by the condition
of the untreated supply water, the effectiveness of the process is
quite limited.
As a means of preventing the formation of tastes and odors in the
stagnant sections of the distributing systems, it is almost universally
successful.
The process proves to be of real assistance in the reduction of
deadend red water complaints.
For prolonged sterilization, it is much more practical than chlorine
alone.
The manual goes on to say Today the ammoniachlorine is widely used and its
limitations are as well understood as its merits.
It is interesting to note that the chlorineammonia process was in use
for some twenty years before the elucidation of the breakpoint phenomenon of
the chlorination of water, which occurred in the late 1930s. With this
discovery, came the realization that free forms of chlorine are more rapid
and effective as disinfectants. Chlorination to a free residual was found
to be an effective means of controlling coliform organisms in newly laid
water mains. The 1950 American Water Works Association Water Quality and
Treatment Manual shows the gain in acceptance of free residual chlorination.
In very recent years, the functional advantage of treatment employing
amounts of chlorine greater than those formerly considered adequate has
become clearly appreciated. The wider adoption of treatment utilizing
greater chlorine additions may be expected to develop in the future, inasmuch
as highrate thlorination provides a means of achieving a higher standard
of bacterial quality and of improving plant practice, including the elimina-
tion of certain types of tastes and odors. The manual goes on to give
2
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definitions of combined residual chlorination that are still applicable
today. Combined residual chlorination is defined as the application of
chlorine to water to produce, with the natural or added ammonia, a combined
available chlorine residual, and to maintain that residual through part or
all of a water treatment plant or distribution system. Free residual
chlorination is defined as the application of chlorine to water to produce
directly, or through the destruction of ammonia, a free available chlorine
residual, and to maintain that residual through part or all of a water
treatment plant or distribution system. By 1950, approximately 500 water
treatment plants in the U.S. were practicing free residual chlorination.
The value of residual chlorine in the distribution system has received
considerable attention. While the military had no policy concerning re-
sidual chlorine, it was recommended by all services that chlorination be
accomplished to levels of free residuals for specified times which under
conditions of natural waters was equivalent to breakpoint. At the request
of the Army, the National Academy of Science&National Research Council
(NASNRC) prepared a statement (1953) which stated in part:
Residual chlorine in the concentrations routinely employed in
water utility practice will not ordinarily disinfect any sizeable
amounts of containinatory material entering the system, though this
will depend on the amount of dilution occurring at the point of con-
tamination, on the type and concentration of residual chlorine and
on the timeofflow interval between the point of contamination
and the nearest consumer .... It is the opinion of the NASNRC
that the establishment of a universal standard for maintaining
residual chlorine in the water in distribution systems is not
desirable .... The NASNRC does not consider maintenance of a
residual a satisfactory substitute for good design, construction
and supervision of a water distribution system, nor does it feel
that the presence of a residual in the system constitutes a guar-
antee of water potability.
Formal scientific discussion on the value and limitation of chlorine
residuals in distribution systems have not taken place since 1958, although
since the war there has been an increase in the number of towns and cities
that maintain residuals in their distribution system. At that time, it was
concluded that agreement with the NASNRC statement was not universal and
that one well documented value of the chlorine residual was the reduction
of coliform organisms in the delivered water. However, at the same time it
was believed that normal residuals could not overcome the infrequent but
devastating external gross contamination by crossconnections and back
siphonage defects. The loss of residual would serve as a valuable tracer
and warning device. The observed lowering of coliform by chlorine was
believed to be merely a control of aftergrowth, the health significance of
which was debatable. Therefore, it was no surprise that controversy on
system residuals still exists. The National Community Water Supply Survey
(CWSS) (McCabe et al., 1970) conducted jointly by the PUS and state health
departments contained bacteriological data from distribution systems for
954 of the 969 systems surveyed serving a population of 18 million. Of the
954 systems 869 did not meet bacteriological surveillance criteria. The
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importance of maintaining a chlorine residual was clearly demonstrated.
The data showed that unless a chlorine residual was maintained in the
distribution system, a significant percent of the samples would not meet
the bacteriological standard. Waterborne outbreaks of disease caused by
contamination of the distribution system through cross connections and back
siphonage have been recorded since the beginning of the twentieth century
and still occur today. Water borne disease outbreaks in the U.S. for the
period 19611970 included gastroenteritis of unknown etiology, infectious
hepatitis, shigellosis, typhoid fever, salmonellosis, infections of entero
pathogenic E. coli, giardisis and amebiasis (Craun and McCabe, 1973).
Craun and McCabe (1973) state that the major cause of outbreaks in public
systems is through contamination of the distribution system primarily via
cross connections and back siphonage. For the period 19461970, 39.4% of
the total number of outbreaks in public systems were caused by contamination
of the distribution system. Only 6.6% of the total cases of illnesses
resulted from these outbreaks, since the contamination of a part of the
distribution system usually affects less people than contamination of the
water source or breakdowns in treatment. However, distribution system
deficiencies have contributed a greater number of cases in recent years.
In municipal water systems during 19711977, the percent of outbreaks
caused by distribution system contamination remained fairly constant compared
to 19461970 to wit: 37% compared to 39.4%, but the percentage of cases of
illnesses increased from 6.6% to 38% (Craun, 1978). When infectious hepa
titis alone is considered, contamination of the distribution system is the
major cause both in numbers of outbreaks and numbers of cases. In public
systems, such contamination resulted in 10 of 17 outbreaks and 295 of 739
cases, for 19461970. For 19711974, 5 additional outbreaks of infectious
hepatitis occurred in public systems, of which one was caused by distribution
system deficiences (Craun et al., 1976).
In addition to the overt outbreaks caused by the pathogens mentioned
above, other microorganisms found in samples from the distribution system
may cause health problems to compromised individuals, particularly, the
infirm in hospitals and individuals taking immunosuppressive drugs. These
microorganisms include species and strains of Pseudomonas, Flavobacterium,
Ae.romonas and Kiebsiella. (Geidrich, 1973).
The maintenance of a chlorine residual, particularly a free residual,
throughout a community water distribution system has been shown to be
effective in meeting bacteriological standards (Buelow and Walton, 1971)
and in controlling the general bacterial population within distribution
lines (Geldrich et al., 1972). Since the water leaving a treatment plant
with accepted treatment practices is almost without exception of good bac-
teriological quality, the superior quality of distribution system samples
in systems that maintain chlorine residuals must be due to the protection
of the residual against bacterial regrowth and posttreatment contamination.
Direct evidence of the role of the chlorine residual in the water distribu-
tion system so far as in the literature is limited.
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SECTION 2
CONCLUSIONS
1. Chlorine residual is functional in the distribution system and
provides protection against posttreatment contamination.
2. A free chlorine residual is more effective in neutralizing micro-
organisms contained in the contaminant than combined residual
chlorine.
3. A free chlorine residual noticeably decreases when challenged with
a contaminant and does serve as a flag.
4. Increased plate count levels were associated with decreased chlorine
residuals and with increased turbidity.
5. The maintenance of a free chlorine residual is the single most
effective measure for controlling the concentration of plate count
microorganisms in the distribution system.
6. A variety of bacterial types, as determined by seven biochemical
tests, is to be found in the distribution system. At any given
sample station, it is likely that 3 or 4 of these groups will pre-
dominate in number and frequency of occurrence.
7. The biochemical groups isolated at 35°C and 20°C were similar.
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SECTION 3
RECOMMENDATIONS
It would appear that the current water works practice of maintaining
some kind of a chlorine residual within the distribution system is justified
on the basis of operational data and reinforced by the results of this
study. The disinfecting superiority of free over combined chlorine species
came as no surprise. The inability of combined chlorine residuals to
function as a warning flag that abnormalities have occurred within the
distribution piping was not expected. The possible adverse effects of
residuals in the distribution system have got to be examined. These effects
are the long standing debate of contribution to chiorotastes whether free,
mono or dichioramine or nitrogen trichioride is responsible and the effect
of producing hazardous byproducts.
It should be apparent that not all distribution systems can achieve
and maintain a persistent free or sometimes even a combined chlorine resi-
dual. More information is needed to characterize such distribution systems.
It could be the layout (lack of circulation), pipe materials, age of
system, water quality and degree of corrosion or deposition. The older
systems in the northeastern towns and cities many beyond 75 years of age,
are available for such study. It may well turn out that water quality may
not be as important as the need to completely renovate the older pipe
system. The cost will be large and efforts to study the causes with view
of prevention might be the best immediate course to pursue.
6
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SECTION 4
DESCRIPTION OF STUDIES
This project was designed to provide microbiological, physical and
chemical evidence obtained from controlled laboratory experiments, pilot
reservoir studies and municipal distribution system observations to evaluate
the benefits, if any, of the maintenance of a free or combined chlorine
residual in public water supplies.
HOLDING TANK STUDIES
Holding tank studies were conducted to obtain basic data on the rela-
tive volume and strength of contamination that can effectively be neutra-
lized with low levels of chlorine residuals. Relative survivals of indi-
cator organisms, pathogenic bacteria, and viruses were evaluated under
conditions commonly found in water distribution systems.
RESERVOIR STUDIES
Reservoir studies were conducted to provide information on the in-
activation of natural populations of coliforms under conditions where the
residual chlorine was continually replenished by reservoir inflow as the
water was withdrawn. The effect of naturally occurring turbidity on the
protective capacity of residual chlorine was evaluated with water taken
from the Little Patuxent River.
MUNICIPAL DISTRIBUTION SYSTEMS
The Baltimore City water system provides services to Baltimore City and
parts of the surrounding counties, including Howard, Baltimore and Anne
Arundel counties. The system takes raw water principally from two pro-
tected reservoirs, Liberty and Loch Raven, and has the capability of
supplementing this supply with water from the Susquehanna River. Figure 1
shows the major elements of the Baltimore City water system and the location
of the sampling sites during this study. Two water treatment plants, em-
ploying coagulation, sedimentation, filtration and breakpoint chlorina-
tion, supply the service area with approximately 250 million gallons of
treated water per day. (Baltimore Regional Planning Council, 1972). The
Montebello treatment plant, located adjacent to sampling site 54 in Figure
1, supplies water to the heavily industrialized southern and southeastern
parts of the metropolitan area. The Ashburton treatment plant, located ad-
jacent to sampling site 23, supplies water to the rest of the system. In
7
-------
Figure 1. 1ajor elements of the Baltimore, Maryland water treatment
and distribution system.
transmisSion main
raw water line
treatment plant
pumping station
storage facility
sample station
8
-------
the distribution system are facilities for storage of treated water, in open
reservoirs or in elevated tanks with provisions for rechiorination. The
majority of the distribution mains in the Baltimore system are unlined cast
iron pipe. There are approximately 1,500 to 2,000 miles of unlined pipe in
the system (Stewart, 1971).
Twentyone sampling sites were selected for weekly monitoring based
on chlorine residual data for the previous year from the records of the City
of Baltimore Bureau of Operations, Water Division. The average monthly free
chlorine residual over the sampling period for each station is shown in
Table 1. The sites were chosen so that as wide a range of free chlorine
residuals as possible would be obtained. The range was from an average of
0.01 mg/liter from a station that frequently showed no free residual to 0.91
mg/liter from a station that consistently showed high free chlorine resi-
duals.
Frederick, Maryland is located approximately 50 miles northwest of
Baltimore. The water supply and distribution system provides service to a
population of 30,000. The city gets water from four sources, two upland
sources receive no treatment other than chlorine and ammonia addition, at
a ratio of 6:1 (C1:N) by weight. The other two sources receive conventional
complete treatment. The four sample sites chosen for this study are on
the western side of Frederick, and receive primarily the chiorammoniated
water from the upland sources, although some mixing occurs in the distribu-
tion system depending on local demand. Most of the pipes in the Frederick
distribution system are cement lined cast iron. Since the time of this
study, the ammonia addition procedure has been terminated and a free chlorine
residual is maintained in the Frederick distribution system.
9
-------
I.-
0
TABLE 1. AVERAGE MONTHLY FREE CHLORINE RESIDUAL FOR SAMPLING STATIONS IN THE
BALTIMORE DISTRIBUTION SYSTEM DURING THE SAMPLING PERIOD (JULY 1977
TO JUNE 1978)
Sample
Station
July
1977
Aug.
Sept.
Oct.
Nov.
Dec.
Jan.
Yeb.
Mar.
Apr.
May
June
1978
Yearly
Average
23
.85
.93
.93
.83
.82
.94
.86
.85
.80
.80
.86
.63
.86
27
0
I)
0
0
0
.1.5
.23
.21
.11
.03
0
0
.0 15
28
.38
.37
.36
.40
.44
.50
.70
.40
.35
.33
.50
.10
.40
.36
.28
.30
.35
.47
.56
.52
.44
.38
.31
.34
.35
.38
30
.10
.26
.23
.31
.150
.68
.65
.55
.49
.34
.32
.13
.38
31
0
0
.06
.03
0
.14
.14
.19
.21
.10
0
.06
.07
54
.13
.33
.40
.21
.25
.64
.33
.30
.415
.19
.17
.19
.28
35
.21
.29
.19
.09
.07
.26
.43
.25
.20
.06
.09
.13
.18
36
.80
.82
.85
.88
.88
.91
.87
.81
.80
.80
.80
.76
.83
37
0
0
0
0
.11
0
.09
0
0
.11
0
0
.02
38
.72
.61
.71
.68
.65
.68
.15
.68
.80
.61
.73
.38
.66
42
.55
.43
.44
.48
.66
.61
.55
.59
.52
.60
.49
.39
.49
43
.55
.26
.29
.35
.42
.53
.53
.53
.51
.36
.43
.25
.42
44
0
0
0
.03
0
.01
.04
.01
0
.14
0
0
.01
45
.95
.86
1.05
1.00
1.06
.89
1.09
1.00
.78
.63
.83
.74
.90
46
.15
.81
.93
1.00
.76
.61)
.96
.14
.66
.63
.66
.76
.77
68
0
0
0
0
0
.01
.60
.01
0
0
0
0
.03
4)
.93
1.06
1.10
1.20
.83
.81
.94
.74
.80
.76
.91
.90
.91
52
.59
.68
.76
.76
.61
.90
.96
.55
.79
.68
.80
.76
.73
53
.08
0
.02
.03
.19
.21
.34
.38
.38
.17
.21
.06
.17
54
.74
.49
.68
.59
.75
.61
.53
.74
.79
.59
.63
.61
.64
-------
SECTION 5
METHODS
HOLDING TANK STUDIES
Contaminant Evaluation
Autoclaved raw sewage, seeded with the test microorganisms, was used as
the contaminant material in batch studies. Since the quality of sewage
arriving at a sewage treatment plant changes from day to day and from hour
to hour, it was necessary to use one sample of sewage for several experi-
ments so that valid comparisons could be made between experimental runs.
The effect of autoclaving and subsequent storage of the sewage was evaluated.
Raw sewage was collected from the Ft. Meade, Maryland sewage treatment
plant #2. The sewage sample was thoroughly mixed and dispensed in 2.5 liter
aliquots. Half of the sewage sample was autoclaved at 121°C for 70 minutes.
Thee other half was left unautoclaved. Both sewages were then stored at 4°C
until their use. All chemical and physical tests were performed according
to procedures in Standard Methods (1975). Ammonia and organic nitrogen
were determined by the Kjeldahl distillation procedure. Total carbon
analysis was performed with a Beckman total carbon analyzer. Turbidity was
determined with a Hach model 2100A turbidimeter. Total solids, total
volatile solids, suspended solids, pH, and biochemical oxygen demand (BOD)
were determined according to standard procedures. Determination of the
chlorine dosage required to reach breakpoint (the amount of chlorine ne-
cessary to produce a free chlorine residual) was performed in 250 ml bottles
into which the raw autoclaved or unautoclaved sewage was dispensed. Sodium
hypochiorite solution in varying amounts were added to the bottles to give
a range of chlorine dosages. After 30 minutes contact time at room tempera-
ture these samples were tested for total chlorine residual by the starch
iodide titration method (Standard Methods, 1975), and checked for the
presence of free chlorine by a modification of the leuco crystal violet
method (Olivieri et al., 1971). pH readings were also made. These chemical
and physical tests were performed on the autoclaved and unautoclaved sewage
on the day of collection and at varying times up to 23 days after collection.
Isolation and Enumeration of Bacteria
Bacteria were isolated from settled sewage drawn from the Baltimore
Back River sewage treatment plant.
11
-------
Coliform
An organism of the coliform group (coliform) was isolated from confirm-
atory brilliant green lactose bile broth by streaking on eosin methylene
blue (EMB) agar and differentiated according to Standard Methods (1975) on
the sis of indole, methyl red, VogesProskauer, and citrate utilization
(IM1 ). An isolate yielding typical green, shiny colonies on EMB and
dispL.yLng the classical +4 IMVIC reaction was chosen for use in subsequent
stud..
Salmonella typhimurium--
Concentration and enrichment procedures and biochemical identification
were performed according to Olivieri (1977). Isolates which were phenylala
nine deaminase, oxidase and malonate negative, positive for mannitol fermen-
tation and lysine decarboxylase, and yielded typical Salmonella reactions
on triple sugar iron agar and lysine iron agar were chosen for serological
testing. Serological identification was performed according to the methods
of Edwards and Ewing (1972) using Difco antisera. An isolate, which was
positive for somatic antigens poiy 0 and group B and was found to contain i-I
anigens i in phase 1 and 1 in phase 2, was chosen for use in subsequent
studies.
Shigella--
The concentration and enrichment procedures of Olivieri (1977) were used
in attempts to isolate Shigella from sewage. Since these attempts were un-
successful, a laboratory strain of S. sonnei was used in the studies.
The three bacterial organisms noted above were tested for susceptibility
to f2 bacteriophage by plating each by the agar overlay technique against a
known high titer f2 stock. All three were found to be nonsusceptible.
Bacterial cultures used in all subsequent inactivation studies were
grown overnight at 35°C in Brain Heart Infusion (Bill) broth, washed 3 times
by centrifugation and finally resuspended in a volume of saline equal to that
of the original culture.
The feasibility of using xylose lysine (XL) agar (Difco, 1972) for
the simultaneous determination of levels of coliform, S. typhirnurium and S.
sonnei was evaluated. Bacterial cultures were grown overnight on tryptone
yeastextract (TYE) broth at 35°C. Bacterial numbers for each culture were
determined separately by pour plates on TYE agar and by spread plates on XL
agar. The coliform, S. typhimurium and S. sorinei cultures were then mixed
and the mixture was plated on XL agar. On XL agar, coliform colonies were
yellow, S. sonnei colonies were pinkishred, and S. typhimurium colonies
were black. The results of the determination of bacterial numbers for the
separate cultures and for the mixture of the three cultures are shown in
Table 2. The XL agar gave comparable recoveries to the TYE agar when
bacteria were plated separately. The determination of bacterial numbers in
the mixed cultures on XL agar gave results comparable to plating each
strain separately on XL agar or TYE agar. No interference was observed
upon plating the mixed culture. Thus, plating on XL medium was found to be
a simple and effective method for determining bacterial numbers in a mixed
culture of coliform organism, S. typhimurium and S. sonnei. This technique
12
-------
TABLE 2. COMPARISON OF TYE AND XL MEDIA FOR THE ENUMERATION OF COLIFORN,
S. typhimurium, AND S, sonnei, AND THE EFFECT OF MIXING THE THREE
ORGANISMS ON THE RECOVERY ON XL AGAR
Bacterial
Strain
Media
Number/mi
Run
1
Run
2
Run
3
coliform
TYE
2.8 x
108
1.9 x
108
1.7 x
108
XL
2.5x
108
l.8x
108
i.2x
108
In mixture
XL
3.5 x
108
2.0 x
108
1.2 x
108
S. typhiinurium
TYE
2.4 x
108
2.2 x
108
2.6 x
108
XL
3.Ox
108
2.3x
108
l.9x
108
In mixture
XL
3.2 x
108
2.6 x
108
1.8 x
108
S. sonnei
TYE
2.3 x
10
2.2
iO
2.4
108
XL
3.Ox
108
2.Ox
108
2.2x
108
In mixture
XL
2.1 x
108
2.6 x
1O
2.1 x
108
13
-------
was used throughout the subsequent studies.
Preparation and Enumeration of Viruses
The f2 bacterial virus was obtained from the American Type Culture
Collection (ATCC # 15766B) and virus stocks were prepared by the method
given by Cramer (1976). The f2 virus was assayed by the agar overlay tech
n.Lcjue (Adams, 1959) using E. coli K13 (ATCC #15766) as the host bacterium.
Poliovirus 1 (vaccine strain) was prepared in Buffalo green monkey (BGM)
cells (Dahling et al., 1974) grown in roller bottles in Eagles minimal
essential medium containing 5% fetal calf serum. The poliovirus was grown
without antibiotics, since the presence of antibiotics would preclude
mixing the poliovirus with the bacterial strains in the inactivation experi-
ments. The virus was harvested by three cycles of freeze thawing, followed
by centrifugation to remove cell debris. Poliovirus plaque assays were done
using BGN cells. All experiments were performed using aliquots from a single
v rus preparation.
Experimental Procedures
A 30 liter volume of Baltimore City tap water was drawn and brought to
the desired temperature. The chlorine residual was measured by amperometric
titration (Standard Methods, 1975) using a SargentWelch Model XVI polaro
graph with dual platinum electrodes and adjusted to the level for the
experiment with the addition of sodium sulfite or chlorine as required.
When a combined chlorine residual was desired, ammonium chloride was added
to a threefold molar excess of ammonia. The water was buffered by the
addition of 0.00Th phosphate and the pH was also adjusted. The schematic
of the procedures used during the experimental runs is shown in Figure 2.
Aliquots of 4 liters were dispensed into polypropylene containers and held
in a constant temperature water bath. The pH and temperature of the auto
claved raw sewage were adjusted and the sewage was seeded with test organisms
(coliform, S. typhimurium, S. sonnei, f 2, and poliovirus 1). At time zero,
predetermined amounts of seeded sewage according to test protocol were
added to the tap water with mixing. Samples for the determination of micro-
bial survivals were withdrawn into tubes containing an excess of sodium
thiosuif ate at 2, 30, 60 and 120 minutes contact time. Chloroform (23
drops) was added to the sample prior to viral analysis to eliminate inter-
ference from bacteria. Analysis for chlorine residual by amperometric
titration was performed in all trials at 2 and 120 minutes after the addi-
tion of sewage, and in some trials the residual chlorine was measured at 2,
30, 60 and 120 minutes.
Levels of seeded, autoclaved raw sewage added to the tap water for each
of the experimental conditions are shown in Table 3. Experimental runs were
performed at either pH 6 or 8, at temperatures of 0, 10, 20 and 30°C, and
with initial free or combined chlorine residuals of approximately 0.2 and
1.0 mg/liter.
Holding tank studies were divided into 4 sections. In each section the
experimental design was to compare the effect of one variable, with other
14
-------
In )
/
Row Sewage with
S. typhimurium , S. sormel ,
a colitorm, poliovirus I, and
f2 virus
Top Water, pH,
Temperature, and
Cl adjusted
Sodium thiosulfate
/ \ HCl3
Bacterial assay
Viral assay
Figure 2. Schematic Holding tank experimental protocol.
15
-------
TABLE 3. PERCENT AUTOCLAVED RAW SEWAGE ADDED TO TAP WATER FOR EACH
OF TUE. EXPERIMENTAL CONDITIONS
% Auto
claved Raw Sewage
1.0
Approximate
Free 1.0
Initial Chlorine Residual,
Combined 0.2 Free
mg/liter
0.2 Combined
pH
6
1%
1% 0.1%
0.01%
5%
5% 0.5%
0.05%
10 %
10% 1.0%
0.1%
pH
8
1%
1% 0.1%
0.01%
5%
5% 0.5%
0.05%
10%
10% 1.0%
0.1%
16
-------
conditions being held constant. The first section dealt with the effect of
pH on the efficiency of microbial inactivation when starting with an initial
combined chlorine residual. Each run consisted of three paired trials,
with the percent sewage constant for each pair and the pH at either 6 or 8.
In the second section the effect of the initial chlorine species (free or
combined) was compared with pH held constant. The third section was similar
to the first, except that the initial chlorine residual in the experiment
was the free species. In the fourth section, pH, chlorine species, and
percent sewage added were held constant and the initial chlorine residual
was varied. This section was designed to facilitate the construction of
concentrationtime relationship plots.
Extended Time Studies
At the end of the 2 hour contact time, 500 ml samples were taken with-
out dechlorination from each sewagetap water mixture. These samples were
held at the temperature of the experimental run for seven days and were
monitored for increases or decreases in bacterial numbers.
RESERVOIR STUDIES
Experimental Procedure
Reservoir studies were similar to the holding tank studies described
above. These studies differed principally in that:
1. the sample volume withdrawn was replaced with an equal volume of
fresh chlorinated water.
2. larger volume tanks were used.
3. raw (unautoclaved) sewage was used as the contaminant.
4. the sewage was not seeded with bacteria, and naturally occurring
coliforms were assayed, and
5. the pH 6 and low (0.2 mg/liter) chlorine residual studies were
omitted.
Reservoir studies were done using two sources of water: tap water from
the Ft. Meade, Maryland water distribution system and water from the Little
Patuxent River. The Little Patuxent serves as the source of raw water for
the Ft. Meade water system. The reservoir system used in these experiments
consisted of two 1500 liter tanks and six 120 liter tanks. The 1500 liter
tanks were filled with the desired water and the pH was adjusted with
concentrated sulfuric acid or saturated sodium hydroxide. The chlorine
residual was adjusted to approximately 1.0 mg/liter by the addition of
sodium sulfite or aqueous chlorine. When a combined chlorine residual
was desired, ammonium chloride was added to a 3fold molar excess of
ammonia. In runs using tap water, one 1500 liter tank was adjusted to a
combined residual and one to a free residual. Three of the 120 liter
tanks were filled with 100 liters of water with a free residual and three
120 liter tanks were filled with 100 liters of water with a combined re
17
-------
sidual. Raw sewage was collected from Ft. Meade sewage treatment plant #2
and was seeded with f2 bacterial virus. At time 0, varying amounts of the
sewage (110%) were added to each of the six tanks and the contents were
mixed. Samples were withdrawn by a spigot at the bottom of each tank. The
total volume withdrawn at each sample time was 25 liters. The first 4
liters were collected for physical measurements and chemical analysis (p1-I,
turbidity, free and total chlorine, temperature), the next 4 liters were
collected for biological analysis, (coliform and f 2) and 17 liters were run
to waste. The tanks were then refilled to the 100 liter mark with the same
water that they originally contained. Samples were analyzed for free
chlorine by the leuco crystal violet method and for total chlorine by the
iodometric method. Turbidity was determined with a Hach model 2100A turbid
imeter. Coliforms were determined using a 5 tube MPN procedure with lactose
broth. All positive tubes were confirmed in BGLB. f2 was titered by the
agar overlay method.
In runs using both tap and river waters, one 1500 liter tank was filled
with tap water and one with river water and the chlorine residual and pH were
adjusted. Two of the 120 liter tanks were filled with 100 liters of tap
water, two with 50 liters of tap water and 50 liters of river water, and
two with 100 liters of river water. In these runs, a constant percent
sewage was added to the tanks, thus, each run consisted of 3 trials with 2
replicates. The sampling procedure was the same as that mentioned above.
Experiments were designed to evaluate the degree of mixing produced by
the addition of the contaminant, withdrawal of sample, and subsequent re-
filling. One liter of fluorescein dye was poured into each of the 6 tanks,
without mixing. Aliquots of 25 liters were then taken from 5 of the tanks,
following the sampling procedure given above. Each sample was mixed, and the
absorbance at 480 nm was determined. The concentration of fluorescein dye
in the sample was calculated from the calibration curve shown in Figure 3.
One of the tanks served as a control to evaluate any loss of fluorescein over
the sampling period. Figure 4 compares the results obtained with the theore-
tical results expected if the tanks were completely mixed. The theoretical
line was obtained by multiplying the control value by the dilution factor.
The results indicate that, even without mixing, the dye becomes distributed
uniformly throughout the tank after addition, and that it redistributes it-
self uniformly after each withdrawal and refilling. The reservoir studies
were originally designed without mixing, in order to simulate the manner in
which a contaminant enters the distribution system. Since it was found
that the tanks became thoroughly mixed by sample withdrawal and refilling,
a manual mixing step was included to insure reproducible conditions.
MUNICIPAL DISTRIBUTION SYSTEMS
Sample Collection and Analysis
Tap water samples were collected from the Baltimore, Nd. and Frederick,
Nd. water distribution systems in sterile polyethylene bottles containing
sodium thiosulfate and were kept in an ice chest until processing. The
maximum time between sample collection and analysis was 8 hours. Sample
site designations in Baltimore are those used by the Baltimore City Water
18
-------
.0 -
E
C
o 0.8
. .
0.6
C.)
C
- 0.4
0
U,
.0
<0.2
0 I I
0 2 4 6 8 0 12 4 IS 8 20
Fluorescein, mg/I
Figure 3. Calibration curve for the determination of
fluorescein concentration.
6
14 \
__
0I
E
.
C.)
II)
I-
0
S
4 I I
0 30 60 90 120
Time, minutes
Figure 4. Effect of sample collection and refilling on
the concentration of fluorescein dye in the
reservoir studies. A, results expected
by dilution for a completely mixed system.
observed result. __ _ .. control.
19
-------
Department, since these samples were collected by personnel of that depart
merit in conjunction with their regular sampling program. Chlorine residual
data and temperature were determined by the sample collector. Since great
reliance was to be placed on the chlorine residual data obtained by the
sample collector, a laboratory study comparing the results obtained by the
collector with a N 1 N 1 diethylpphenylene diamine (DPD) kit with the results
obtained by amperometric titration on a series of chlorinated water samples
was performed. The results, shown in Figure 5, indicate that good corre-
lation (R = 0.988) was obtained.
Samples were analyzed for turbidity using a HachModel 2100A turbidi
meter and total coliform tests were performed in lauryl tryptose broth
using a five tube most probable number (MPN) technique with sample volumes
of 10.0, 1.0 and 0.1 ml (Standard Methods, 1975). Plate counts were done
at 35°C after 48 and 96 hours incubation, and at 20°C after 9 days incuba-
tion, using plate count agar (Difco, 1972).
Microbial Differentiation
Isolates obtained from 8 of the sampling sites on plate count agar at
20°C and 35°C were subjected to a biochemical screening procedure. The
sampling sites involved were numbers 1 and 4 in Frederick and numbers 27,
34, 37, 43, 44 and 48 in Baltimore. A maximum of 48 colonies from each site,
24 at each temperature, were screened for catalase activity, oxidase, mo-
tility, indole production, and aerobic and anaerobic utilization of glucose
(OF test). In the later months of the study, colonies were also screened
for growth on Simmons citrate and MacConkey agar and for nitrate reduction.
Colonies were picked at random onto a master plate of plate count agar
and allowed to grow. A toothpick replicator (Markowitz 1977) was used to
transfer an innoculum from the master plate to 24 well CoStar tissue culture
dishes. Each well contained 2 ml of the appropriate agar media. A second
master plate was innoculated at the end of each run to insure that a suff i
cient innoculum was carried to each plate. Colonies subject to the follow-
ing tests were incubated at the temperature at which they were first iso
lated. Recommended incubation time for testing oxidase and catalase ac-
tivity is 1824 hours. However, slow growing colonies were incubated for
up to 96 hours. Positive and negative control cultures were routinely in-
cluded for each test.
Since the toothpick replicator is relatively new procedure, a compari-
son of this method with conventional tube methods (MacFaddin, 1976) was done.
The results for 300 isolates from each temperature are shown in Table 4.
Greater than 98Z agreement between the two methods was obtained for aerobic
and anaerobic production of acid from glucose and production of indole. The
lowest agreement was in the detection of anaerobic growth, with 92.5% at 20°C
and 93.1% at 35°C. Biochemical tests were performed according to the fol-
lowing procedures:
Catalas e
Several drops of 3% H20 2 were added to each colony on nutrient agar con-
taining 1% glucose. The evolution of gas was recorded as positive (MacFad
20
-------
0
Free chlorine , omperometric titrotiori
Figure 5.
Free chlorine residual determination by sample
collector with DPD versus free chlorine deter-
mination by amperometric titration.
0.6
0
0
C
I-
0
0.2
0
0 0.2 0.4 0.6 0.8
1.0
21
-------
TABLE 4. COMPARISON OF THE TOOTHPICK REPLICATOR METHOD WITH CONVENTIONAL
TUBE METHODS FOR BIOCHEMICAL TESTS FOR ISOLATES FROM PLATE COUNT
AGAR AND KNOWN CONTROL CULTURES
Test
Temp
°C
%
agreement
Toothpick
% False
Positive
Replicator
% False
Negative
Acid from
20
99.4
0.6
0
glucose aerobically
35
98.8
0.9
0.3
Acid from
20
100.0
0
0
glucose anaero-
bically
35
99.6
0.4
0
Anaerobic
20
92.5
3.3
4.2
growth
35
93.1
2.9
3.9
Motility
20
93.9
3.2
2.9
35
96.1
2.1
1.8
Indole
20
99.7
.03
0
35
99.7
0
.03
22
-------
din, 1976).
Oxidas e--
Equal volumes of 1% aqueous p-azninodimethylaniline oxalate and 1% alpha
naphtol in 95% ethanol were added to colonies grown on standard plate count
agar. The development of a blue color within 2 minutes was recorded as
positive. (Edwards and Ewing, 1972).
Indole
Detection of indole was performed on SIM medium (Difco, 1953) using
paper discs impregnated with Kovacs indole reagent. Development of a
reddishpurple to red color within 3 minutes was recorded as positive.
(MacFaddin, 1976).
OF Test--
Hugh and Leif sons OF basal medium was used to determine aerobic and
anaerobic growth and utilization of glucose after 7 days incubation.
Duplicate plates were innoculated, one incubated aerobically, and one
anaerobically in a GasPak anaerobic system (MacFaddin, 1976).
Motility
Motility was determined by spreading growth on SIM medium, after 4 to
6 days incubation. (Difco Manual, 1953).
The following tests were performed on isolates by conventional tech-
niques in the later months of the study.
Nitrate Reduction
Semisolid nitrate agar (0.5% agar, Difco) was innoculated by stabbing to
the butt of the tube and streaking the slant. Incubation time was generally
2448 hours, with some slow growing isolates incubated up to 9 days. Nitrate
reduction was tested by the method given in MacFaddin (1976) using Naphthyl
amine hydrochloride reagent and 0.8% sulfanilic acid in 5N acetic acid.
Citrate
The ability of isolates to use citrate as the sole carbon source was
tested by innoculating Simmons citrate agar (Difco, 1953) and incubating it
for up to 9 days. The development of a blue color was recorded as positive.
MacConkey -
The ability of the isolates to grow on MacConkey agar (Difco, 1972) was
tested by innoculating slants and incubating them for up to 9 days. Growth
and alkaline or acid reaction was recorded.
Gram Stain
Isolates were stained by the procedure given in Standard Methods (1975).
Positive lauryl tryptose tubes in the coliform assay were transferred for
confirmation to brilliant green lactose broth (BGLB). Positive BGLB tubes
were streaked onto eosin emthylene blue agar for isolation. Several isolates
obtained on each plate that showed typical green shiny colonies were tested
for IMVIC reactions and Gram stain. (Standard Methods, 1975).
23
-------
SECTION 6
RESULTS
HOLDING TANK STUDIES
Contaminant Evaluation
The effect of autoclaving and subsequent storage of raw sewage on am-
monia and total nitrogen, total carbon, turbidity, total solids, total
volatile solids, suspended solids, pH, BOD, and the amount of chlorine
required to reach the breakpoint was determined on initial sewage samples.
These determinations were made on autoclaved and unautoclaved raw sewage on
the day of collection and at elapsed times of 1, 3, 7, 11, 16 and 23 days.
The effect of steam sterilization and storage on the chemical parameters
monitored is shown in Figure 6. Autoclaving the sewage resulted in an im-
mediate increase in pH from 7.1 to 8.9. After this initial increase, the
pH of the autoclaved and unautoclaved sewage remained constant over the 23
day period. Autoclaving and storage had no effect on total carbon, organic
nitrogen, total and suspended solids, and biochemical oxygen demand (BOD).
The turbidity of the unautoclaved sewage decreased from 65 nephelometric
turbidity units (NTU) to 40 NTU, while the turbidity of the autoclaved
sewage remained constant at 65 NTU.
Chemical parameters most important in the behavior of the simulated con-
taminant holding tank studies were ammonia nitrogen and chlorine breakpoint.
The ammonia nitrogen concentration in the raw sewage increased from 20 mg/li-
ter to 24 mg/liter over 23 days, while that of the autoclaved sewage remained
constant at approximately 18 mg/liter. This increase in ammonia nitrogen
in the raw sewage was followed by an increase in the breakpoint from 220
mg/liter to 260 mg/liter. The breakpoint for the autoclaved sewage remained
constant at 210 mg/liter.
Differences in the stability of the breakpoint for the autoclaved and
raw sewage are shown in the breakpoint curves in Figures 7 and 8. Figure 7
shows that the breakpoint for autoclaved sewage remains constant at 210
mg/liter and that the shape of the breakpoint curve does not change over
the 23 day period. Figure 8 indicates that, in addition to the increase in
the breakpoint dosage, the shape of the breakpoint curve changes substan-
tially with time for the raw sewage.
The autoclaved raw sewage was found to be stable in those parameters im-
portant for the subsequent studies, and provided a reproducible source of
24
-------
200
8
S
.
0
TOThL
0
__________
-
SUSPENDED
25
20 ___________ ___________ ______________ ____________________
IS
I0
S
2c
IS,___________ ______ ________ ____________
10
5
C
lOG
£
50
- 0-- -. --0 _0
C. . .
0 I 2 3 4 f 6 7 8 9 10 II 12 13 4 IS 16 17 18 9 20 21 22 2 24
TIME, days
Figure 6.
Effect of storage at 4°C on selected chemical parameters
for raw sewage (0) and autoclaved raw sewage ( )
2 SC
200 S 0
8 S
a: ISO
o
E tOO
50
400
a
250
200
- Q
0--_
.
S
I-
z
0
z
z
a
-O O
S
0
O__ 0 0 -
200
0
0
S S
0
I-
IOC
IC
S
X 8
7
25
-------
I
0 .
E
-J
4
D
0
U)
L i i
w
z
0
-J
I
C)
Figure 7.
CHLORINE DOSAGE, mg/I
280
Effect of storage at 4°C on the chlorine breakpoint
curve for autoclaved raw sewage.
DOSAGE, mg/I
Figure 8.
Effect of storage at 4°C on the chlorine breakpoint
curve for raw sewage.
:
B
7
6
140
120
100
80
60
40
20
0
0 40 80 120 160 200 240
- - -
I0
9
B
0.
7
6
140
120
E
. 100
-J
4
0
U)
IhJ
80
Lii
z
0
-J
I
0
60
40
20
0
0 40 80 120 160 200 240 280
CHLORINE
26
-------
chlorine demanding material. Sewage collection was, therefore, done on a
monthly basis, with one sewage sample used for the entire month.
Microbial Survival
The concentrationtime relationship for 90% inactivation of the three
test bacteria when 1 or 2% sewage was added to tap water containing an
initial combined or free chlorine residual, respectively, is shown in
Figure 9. The inactivation in this series of experiments follows the
classical dependence on disinfectant concentration and contact time. Since
the test microorganisms were mixed together, they were exposed to identical
conditions, and valid comparisons of susceptibility can, therefore, be
made. Little differences in the concentrations of chlorine and contact
time required for inactivation were observed for the three bacteria. A
note of caution should be made in the interpretation of this figure. The
results obtained are dependent on the amount of sewage added, the character-
istics of the sewage, and the initial species of chlorine employed. In the
case where an initial free chlorine residual was used, the observed inactiva-
tion may be due to the momentary presence of free chlorine after the addition
of the sewage, or to the resulting combined forms of chlorine.
The inactivation curves of the coliform organism, f 2, and polio 1 under
varying conditions of initial free or combined chlorine residuals and sewage
levels are shown in Figures 10 through 12. Results shown are mean values of
4 to 8 trials, averaged over the 4 test temperatures (0, 10, 20 and 30°C) and
utilizing different batches of sewage. Results for each individual trial are
found in Appendix A. For clarity of graphical presentation, the results for
S. typhiznurium and S. sonnei were omitted, since these organisms behaved
similarly to the coliform organism (shown above). The data for S. typhi
muriwn and S. sonnei can also be found in Appendix A. Figure 10 shows the
inactivation of the coliform, f2 and polio 1 at pH 8 in the presence of 1,
5 and 10% added sewage, with an initial free or combined chlorine residual
of approximately 1 mg/liter. The results are plotted as log N/N 0 , where
N 0 is the number of microorganisms at time zero, and N is the number of
microorganisms at any time t. An initial free chlorine residual was more
effective than an initial combined chlorine residual for 1% sewage, with
greater than 2.7 logs inactivation of the coliform in 30 minutes occurring
with the free residual and 2.0 logs inactivation in 120 minutes occurring
with the initial combined residual. The free residual was also more effec-
tive against f2 and poiio at 1% sewage. At the higher sewage levels, the
initial free and combined residuals were equally ineffective against the
introduced microorganisms, with 0.5 log or less difference in the inactiva-
tion after 2 hours contact time. Both residuals decreased in effectiveness
as the level of sewage was increased. At 10% sewage, less than 1 log
bacterial inactivation and almost no f2 inactivation was obtained.
Figure 11 shows the inactivation curves of the coliform, f2 and polio
virus 1 at pH 6 under the same conditions of sewage levels and initial chlo-
rine concentration. An initial free chlorine residual was markedly more
effective at this pH, with greater than 3 logs bacterial inactivation
occurring in 2 minutes at 1% sewage and in 30 minutes at 5% sewage. The
average bacterial inactivation with an initial combined residual with 1%
27
-------
3.0 I
2.0
= A
M
1.0 _. D A pH 8
0.8 rn.
u 0.2
I 5 10 50 100 200
Time (minutes)
0 cotitorm
U 0 typh mun m
A S. sonnet
3.0
2.0
IJ -S. .---
E j U -. pH8
S.-
0.6 A UP,
pH 6 AOD_
0.4
-C
U
0.2
0.1 p
$ 5 $0 50 100 200
Time (minutes)
Figure 9. Concentrationtime relationship for 90% inactivation of
test bacteria, on the basis of the initial chlorine residual.
A. Initial combined chlorine residual, 20°C, 1% added
sewage.
B. Initial free chlorine residual, 20°C, 2% added sewage.
28
-------
Coliform Virus
o 0
N
- I N - -
S 5.. U_
- -2
0
-j
-3 1% -3,
. I 4 _______________________________________________________
o 30 60 90 120 0 30 60 90 120
0 . 0
Z -2
3 5% 3 50/ ,
_41_
0 30 60 90 120 0 30 60 90 120
0 0
I (
0
z
z
-2 10% 2 10%
0
-J
-3 -3
4 I __________________________
0 30 60 90 20 0 30 60 90 20
Time, minutes Ti r e, minutes
Figure 10. Inactivation of the coliform (0), f2 (A) and
poliovirus 1 (0) by an approximate initial chlorine
residual of 1 mg/liter in the presence of 1, 5 and
10% sewage at pH 8.0. Open symbols initial free
chlorine residual, average of 4 trials. Closed sym-
bols initial combined chlorine residual, average
of 7 trials.
29
-------
Coliforin Virus
o 0
a
Z \
U
z
-2
A
- t°t 0
4 I 1 I
0 30 60 90 120 0 30 60 90 20
0 Ci ______
£
0_I l I
2
I \
-2
o
3 -\ 5% -3 50/
0
_____________________ -4 I
0 30 60 90 20 0 30 60 0 20
0
),
-I
Z2 -2
o tO % IOd/o
-3. 3
-4 _____________________ -4 _____________________
o 30 60 90 20 0 30 60 90 20
Time, minutes Time, mirutes
Figure 11. Inactivation of the coliform (0), f2 ( ) and
polioviros 1 (0) by an approximate initial chlorine
residual of 1 mg/liter in the presence of 1, 5 and
10% sewage at pH 6.0. Open symbols initial free
chlorine residual, average of 5 trials. Closed sym-
bols initial combined chlorine residual, average
of 8 trials.
30
-------
sewage at 2 minutes was 0.2 logs and with 5% sewage at 30 minutes the
inactivation was 1.5 logs. The conditions of pH 6 and an initial free
chlorine residual with 1% sewage was the only case where reductions of f2
and polio 1 to the lower sensitivity limit of the assay were obtained. A
combined residual was ineffective against f2 under any of the conditions
tested. Again, the efficiency of the residuals in inactivating the intro-
duced microorganisms decreased as the sewage level increased, and the
marked difference in the effectiveness of the free versus the combined
residual disappeared.
Inactivation curves for 0.1% added sewage with an initial 0.3 mg/liter
free or combined chlorine residual at pH 6 and 8 are shown in Figure 12.
Data for 0.01 and 0.05% sewage with an initial combined residual and 0.2
and 0.5% sewage with an initial free chlorine residual are given in Appendix
A. This disparity in sewage levels tested for the initial low level chlorine
residuals is due to the fact that the difference in effectiveness of the free
and combined residuals was more apparent at lower levels. Experimental con-
ditions were set up to give a range of inactivation from slight inactivation
to reduction to the sensitivity limit. This dictated the use of higher
sewage levels when using an initial free residual. The comparable results
shown in Figure 12 demonstrate the superiority of the initial free residual.
The difference in inactivation is particularly evident at pH 6, where re-
ductions of the coliform to the sensitivity limit of the assay occurred
within 2 minutes with an initial free chlorine residual, while equivalent
reductions with an initial combined residual required 2 hours.
The results shown in Figures 10 through 12 have been replotted in
Figures 13 through 15 so that the effect of pH can be seen more readily.
In all cases, whether starting with an initial combined or free residual,
and at sewage levels of 0.1 to 10%, greater inactivation was observed at pH
6 than at pH 8. Figure 13 compares the inactivation of the coliform, f2
and polio virus 1 at pH 6 and pH 8 under the conditions of an approximately
1.0 mg/liter initial free chlorine residual and 1 to 10% added sewage. The
difference in inactivation between the two pH levels is particularly evi-
dent at 1 and 5% sewage for the coliform, with greater than 3 logs inactiva-
tion in two minutes at pH 6 and 1.4 logs inactivation at pH 8 with 1%
sewage, and 2.5 logs inactivation at pH 6 and 0.1 log inactivation at pH 8
in two minutes for 5% sewage. For polio virus 1 and f 2, 2 logs or greater
inactivation was obtained in 2 minutes at pH 6, with less than 1 log inac-
tivation at pH 8, in the presence of 1% sewage. The effect of pH is not as
great when starting with a combined chlorine residual, as is shown in
Figure 14. Although the degree of difference was smaller with a combined
residual, greater inactivation was obtained at pH 6. Figure 15 shows that
the same trends were evident when lower chlorine residuals and sewage
levels were employed.
Chlorine Residuals
The mean time zero, 2 minute, and 120 minute free and total chlorine
residuals accompanying the experimental trials shown in the previous figures
are shown in Table 5. Complete chlorine residual data is found in Appendix
A. A total chlorine residual was always detected 120 minutes after sewage
31
-------
Col iform
pH6
0,
0.1,0
-4
0
I
0 30 60 90 120
pH B
0 /
0.I
0...
-0
I I
:30 60 90 120
Time, minutes
0
f2
0
-I
\
-2
pH 6
0.1010
4
-I
0 30 60 90 120
6
\
I
pH 8
0. ! %
0 30 60 90 120
Time, mw utes
0
l
-2
-3
A
Figure 12.
Inactivation of the coliform (0) and f2 (.σ) in
the presence of 0.1% sewage with an approximate
initial chlorine residual of 0.3 mg/liter at pH
6.0 and 8.0. Open symbols initial free chlorine
residual, average of 4 trials. Closed symbols
initial combined chlorine residual, average of
5 trials.
S
0
z
z
0
-J
-2
-3
z
z
0
.:
-4
32
-------
Coliform Virus
o a
3 I% lob
, I _4
0 30 60 90 20 0 30 60 90 20
0 0
3 5% 3 50/
.0 I _ I V I I I
0 30 60 90 120 0 30 60 90 120
0 __ 0 -a-a
:
.J 3 i0% 3 0%
-4 i i i ,
0 30 60 90 120 0 30 60 90 20
Time, minutes Time, minutes
Figure 13. Inactivation of the coliforin (0), f2 ( 1 A) and polio
virus 1 (0) by an approximate initial free chlorine
residual oi 1 mg/liter in the presence of 1 to 10%
sewage at pH 6 (open symbols), average of 5 trials
and pH 8 (closed symbols), average of 4 trials.
33
-------
Coliform Virus
o 0
o \
Z _.
-2 o -
0
0
_1 10/0 1%
-4 i I
0 30 60 90 120 0 30 60 90 120
O - - -!
z_ 2 -2
0 50/ 5%
-4 -4 _____________________
0 30 60 90 120 0 30 60 90 20
0 0 £
.. I
o -
z
z-2 -2
o me, 10°
0
-4 ____________________ - ____________________
0 30 60 90 120 0 30 60 90 120
Time, minutes Time mirwtes
Figure 14. Inactivation of the coliforin (0), f2 ( ) and
poliovirus 1 (0) by approximate initial combined
chlorine residual of 1 mg/liter in the presence of
1, 5 and 10% sewage at pH 6 (open symbols), average
of 8 trials and pH 8 (closed symbols), average of
7 trials.
34
-------
Coliform f2
o T ---. -
-I
0
z
S...
z 2 , -2
0
combined combined
0.1% 0 0.I ,o
I I I J I
0 30 60 90 120 0 30 60 90 20
0 0
free free
-l 0.1% -I \ \ .: ..i
90 I 0 O
Time, minutes Time, minutes
Figure 15. Effect of pH on the inactivation of the coliform (0)
f2 ( ) and poliovirus 1 (0) by an initial approximately
0.3 mg/liter free or combined chlorine residual in the
presence of 0.1% sewage. Open symbols pH 6.0,
average of 4 to 5 trials. Closed symbols pH 8.0,
average of 4 to 5 trials.
35
-------
TABLE 5. MEAN CHLORINE CONCENTRATIONS AFTER ADDITION OF VARYING AMOUNTS OF SEWAGE
AT pH 6 AND 8
Mean initial chlorine
concentration (standard
2
c
minute mean chlorine
oncentration (standard
120
co
minute mean chlorine
ncentration (standard
%
sewage
deviation)
deviation)
deviation)
pH
added
free total
free total
free total
8 1.0 1.02 (.26) 1.22 (.25) .03 (.01) .81 (.11) .01 (.01) .76 (.11)
1.0 0 1.07 (.14) 0 .90 (.12) 0 .85 (.12)
5.0 1.02 (.26) 1.22 (.25) .01 (.01) .47 (.11) 0 (.005) .46 (.11)
5.0 0 1.07 (.14) 0 .64 (.13) 0 .55 (.16)
10.0 1.02 (.26) 1.22 (.125) 0 (0) .28 (.16) 0 (0) .23 (.16)
10.0 0 1.07 (.14) 0 .38 (.16) 0 .34 (.17)
6 1.0 1.02 (.23) 1.21 (.24) .06 (.02) .83 (.14) .02 (.02) .77 (.13)
1.0 0 1.07 (.14) 0 .97 (.09) 0 .84 (.13)
5.0 1.02 (.23) 1.21 (.24) .01 (.01) .50 (.10) 0 (0) .41 (.08)
5.0 0 1.07 (.14) 0 .67 (.14) 0 .53 (.14)
10.0 1.02 (.23) 1.21 (.24) 0 (0) .24 (.11) 0 (0) .16 (.09)
10.0 0 1.07 (.14) 0 .38 (.21) 0 .27 (.19)
8 0.1 .24 (.02) .36 (.02) .04 (.01) .23 (.01) .02 (.01) .21 (.01)
0.1 0 .31 (.06) 0 .27 (.05) 0 .26 (.06)
6 0.1 .25 (.05) .36 (.05) .07 (.03) .26 (.03) .04 (.01) .23 (.05)
0.1 0 .30 (.06) 0 .29 (.06) 0 .27 (.07)
-------
addition under all of the conditions tested. This total residual was
generally in the combined chlorine form, with traces of free chlorine
detectable only under conditions of low dosage levels and pH 6. The total
chlorine residual was always larger when an initial combined residual,
opposed to an initial free residual, was used, even though the mean initial
concentration was higher for free chlorine. The difference in the total
chlorine residual at 2 and 120 minutes with an initial free or combined
residual is shown on a percentage basis in Table 6. This table was con
structed by taking the percent of the initial total residual remaining at 2
and 120 minutes for each trial, and then averaging the resulting percentages
for each set of conditions. The total chlorine residual at 2 minutes was
11 to 23 percent lower when starting with a free chlorine residual than for
an initial combined chlorine residual. Increasing the amount of sewage
added resulted in a decrease in the chlorine residual.
Extended Time Studies
The results from the series of experiments where samples were held over
an extended time period for monitoring of regrowth or dieaway of the
coliform organism are shown in Figure 16. Complete data for coliform, S.
typhimurium and S. sorznei are presented in Appendix B. Figure 16 was
constructed from data averaged from 66 samples, regardless of pH, tempera-
ture, chlorine residual and sewage levels, and shows general trends obtained
for ailconditions (pH6 or8; 0.01 to 10% sewage; 0, 20, 30°C, and 0.2 to 1.0
mg/liter free or combined residual). In 35 out of the 66 samples, inactiva-
tion of the coliform organism to the lower sensitivity limit of the assay
(3.8 logs average) occurred within 2 hours. In another 26 samples, the
average inactivation after 2 hours contact was 1.8 logs (range 0 to 3.5
logs), with inactivation to the sensitivity limit of the assay occurring
within 24 hours. In both cases, no regrowth of the microorganism was
observed after reductions to the sensitivity limit had occurred. The re-
maining 5 samples are representative of the cases where the initial chlorine
residual was ineffective against the introduced contaminant. This occurred
at the higher sewage levels tested for each range of initial chlorine
residuals. The maximum increase in bacterial numbers obtained over the
storage period was 0.6 logs, while the greatest decrease was 0.5 logs.
Figure 16 also shows the average changes in bacterial numbers over a 7 day
period which occurred in the 13 dechlorinated controls accompanying the 66
samples. The maximum increase in bacterial numbers was 1.2 logs, while the
greatest decrease was 0.6 logs. Results obtained with the freshly isolated
strain of S. typhirnurium and the laboratory strains of S. sonnei were
similar to those shown here for the coliform.
RESERVOIR STUDIES
Reservoir studies were originally designed without mixing, in order to
simulate the manner in which a contaminant enters a large tank or reservoir
in the distribution system. Since it was found that the tank becomes tho-
roughly mixed by sample withdrawal and refilling, the tanks were mixed
after contaminant addition, to insure reproducible conditions.
37
-------
TABLE 6. CHLORINE RESIDUAL CONCENTRATIONS AFTER SEWAGE ADDITION, AS PERCENT OF INITIAL TOTAL CHLORINE
CONCENTRATION
pH
8
6
8
6
percent
sewage
added
Mean initial
(standard
Free
Cl concentration
deviation)
Total
Total Cl
% of Initial
(standard
2 mm
concentration
concentration
deviation)
120 mm
as
1.0
0
1.07 (.14)
84 (6)
79 (6)
1.0
1.02 (.26)
1.22 (.25)
68 (8)
63 (8)
5.0
5.0
0
1.02 (.26)
1.07 (.14)
1.22 (.25)
60 (10)
42 (17)
51 (14)
40 (16)
10.0
10.0
0
1.02 (.26)
1.07 (.14)
1.22 (.25)
37 (16)
26 (17)
32 (16)
22 (16)
1.0
1.0
0
1.02 (.23)
1.07 (.14)
1.21 (.24)
88 (3)
69 (3)
79 (14)
64 (3)
5.0
5.0
0
1.02 (.23)
1.07 (.14)
1.21 (.24)
63 (11)
43 (11)
49 (14)
35 (9)
10.0
10.0
0
1.02 (.23)
1.07 (.14)
1.21 (.24)
36 (20)
22 (12)
26 (19)
15 (10)
.10
.10
0
.24 (.02)
.31 (.06)
.36 (.02)
88 (1)
65 (5)
83 (5)
62 (6)
.10
.10
0
.25 (.05)
.30 (.06)
.36(..05)
94 (5)
73 (6)
87 (7)
63 (9)
-------
41 1 13 dechlorinated controls
o - - : - - - - -i
5 samples
- l
z
z_ 2
+26 samples
η35 samples
-- £senS vu?ylIrnI!k
-4
-5
0 24 48 72 96 120 144 168
Time (hours)
Figure 16. Effect of long term storage on the level of the coliforin
organism in sewagetap water mixtures. The bars represent
one standard deviation around each point.
-------
The first series of experiments was performed using tap water as the
water source. Complete data for this and other runs are found in Appendix
C. Figure 17 shows the inactivation curves of coliforms and f2 in the
presence of 1, 5 and 10% sewage with an initial 0.38 0.52 mg/liter free
chlorine residual, (0.85 0.93 mg/liter total chlorine) at pH 8.0 to 8.4
and 2829°C. Biological date were corrected for dilution, so the curves
indicate the actual inactivation observed. Table 7 gives the chemical data
for this experimental run. Three logs inactivation of coliforms were
observed after 120 minutes contact time with 1% sewage, while between 1 and
2 logs removal were observed with the higher percentages of sewage. The
bacterial virus, f2 was more resistant than coliforms, with a maximum
inactivation of 2 logs with 1% sewage. Chlorine residual data show no free
chlorine present after the addition of the contaminant. The total chlorine
residual remains fairly constant after the initial decrease caused by the
addition of sewage. Results obtained under similar conditions in the
holding tank experiments were presented in Figure 10. In the holding tank
studies the contaminant was seeded autoclaved raw sewage instead of the raw
sewage with natural coliform populations used in the reservoir studies.
The studies also differed in the fact that the sample withdrawn was replaced
with fresh water containing chlorine in reservoir studies, but not in
holding tank studies. Greater inactivation was observed in the reservoir
studies at higher sewage levels, while greater Inactivation was observed in
the holding tank studies at lower sewage levels.
Figure 18 shows the inactivation curves of coliforms and f2 in the
presence of 1, 5 and 10% sewage (initially) with an initial combined chlorine
residual of 1.5 mg/liter at pH 8.2 8.4 and 2830°C. Table 8 gives the
accompanying chemical data. Greater than 3 logs reduction of coliform were
observed after 2 hours contact time, even with 10% sewage present. While
the inactivation of f2 was slower, 3 logs reduction did occur in the pre-
sence of 1% sewage. The inactivation curves obtained in the holding tank
studies under similar conditions are given in Figure 10. The magnitudes of
the reduction in coliform and f2 were greater in the reservoir system.
Figure 19 shows the inactivation curves obtained in the presence of 1%
sewage with an initial combined chlorine residual in tap and river water at
2729°C. The pH was adjusted to 8.0 in all experiments and the effect of
the different water sources was observed. The chemical data are given in
Table 9. The inactivation of f2 was greater in tap water than in the 1:1
mix of tap and river water or in river water. Greater than 2.5 logs inac-
tivation of f2 occurred in the tap water after 120 minutes contact, while
less than 1 log removal was observed with river water present. The degree
of difference in the inactivation of coliforms with the different water
sources was less than for f 2, but they generally followed the same trend.
The Inactivation was greatest in tap water and least in river water, with a
1:1 mix yielding an intermediate result.
MUNICIPAL DISTRIBUTION SYSTEMS
Microbiological Aspects
40
-------
0 30 60 90
Time , minutes
10 6
120
fz
5.0,10.0 %
V
V 1.0 %
30 60
Time , minutes
90 120
Figure 17.
Inactivation of natural populations of coliforms and seeded
f2 virus contained in sewage after addition to tap water in
the reservoir with 0.38 to 0.52 mg/liter free chlorine
(0.850.93 mg/liter total chlorine) at pH 8.0 to 8.4,
2829°C. The precent sewage was added as indicated.
0
colitorm
-l
C
0
. z
- .
-2
U
0
U-
-3
-4
--D 5.0%
10.0 .1.
0
-I
0
z
Z
C
o2
-3
-4
0
41
-------
TABLE 7. CHEMICAL DATA AFTER THE ADDITION OF RAW SEWAGE TO TAP WATER
FROM ThE FT. MEABE, MARYLAND WATER DISTRIBUTION SYSTEM WITH
FREE CHLORINE AT 2829°C
Chlorine
Residual, mg/i
Sample
%
Sewage
Turbidity
Time
Added
Free
Total
NTU pH
0
1.0
.41
.85
8.2
10
0
.62
2.5
8.4
30
0
.67
1.5
8.4
60
0
.67
1.5
8.4
90
0
.72
1.5
8.4
120
0
.70
1.2
8.3
0
5.0
.38
.74
8.2
10
0
.35
3.3
8.1
30
0
.37
3.4
8.2
60
0
.48
2.9
8.2
90
0
.74
2.5
8.1
120
0
.62
2.0
8.2
0
10.0
.52
.93
8.2
10
0
.14
5.3
8.1
30
0
.21
5.1
8.0
60
0
.39
4.2
8.1
90
0
.49
3.1
8.1
120
0
.55
2.8
8.1
42
-------
Time , minutes
Figure 18.
Inactivation of natural populations of coliforms and
seeded f2 virus contained in sewage after addition to
tap water in the reservoir with 1.50 mg/liter combined
chlorine at pH 8.28.4, 2830°C. The percent sewage
was added as indicated.
0
coliform
-2
-3
-4
10.0%
0 30 60 90
Time , minutes
: °
C
00
C-,
a
I-
U-
z
(j)Z
C
00
C -,
a
I-
U.
20
0
-2
-3
-4
5.0,10.0%
0 30 60 90
1.0 %
120
43
-------
TABLE 8. CHEMICAL DATA AFTER THE ADDITION OF RAW SEWAGE TO TAP
WATER FROM THE FT. MEADE, MARYLAND WATER DISTRIBUTION
SYSTEM WITH COMBINED CHLORINE AT 2830°C
Sample
%
Sewage
Total Chlorine
Turbidity
Time, mm.
Added
residual, mg/i
NTU pH
o 1.0 1.50 8.2
10 1.30 2.0 8.3
30 1.44 2.0 8.4
60 1.44 1.3 8.4
90 1.43 1.1 8.3
120 1.36 1.1 8.3
o s.o 1.52 8.3
10 1.00 3.4 8.2
30 1.09 3.1 8.2
60 1.13 2.3 8.2
90 1.34 1.9 8.2
120 1.30 1.7 8.2
0 10.0 1.50 8.3
10 .65 5.2 8.2
30 .70 4.8 8.2
60 .74 3.5 8.2
90 .92 3.0 8.2
120 .95 2.5 8.2
44
-------
cohform
Time , minutes
o
: i------
30 60 90 Q
Time , minutes
Figure 19. Inactivation of natural populations of coliforms and
seeded f2 virus contained in sewage after addition to
tap water (0), 1:1 tap and river mixture Cs), and
river water (v) in the reservoir with 1.21.3 mg/liter
combined chlorine at pH 8.0, 2729°C.
45
-------
TABLE 9. CHEMICAL DATA AFTER THE ADDITION OF 1% RAW SEWAGE TO TAP
WATER, A 1:1 MIXTURE OF TAP AND RIVER WATER, AND RIVER
WATER WITH COMBINED CHLORINE AT 27-29°C
0
10
30
60
90
120
0
10
30
60
90
120
0
10
30
60
90
120
1.30
1.20
1.22
1.21
1.21
1.21
1.22
1.10
1.10
1.11
1.11
1.09
1.18
98
.98
1.03
1.00
.98
.80
1.1
1.3
1.6
.74
.72
4.7
3.6
4.5
3.7
4.1
4.0
7.0
5.4
6.5
7.8
7.0
7.3
8.1
8.1
8.1
8.1
8.1
8.0
8.0
8.0
8.0
8.0
8.0
8.0
8.0
8.0
8.0
Water
Sample
Total chlorine
Turbidity
Source
Time, mm.
residual, mg/i
NTU pH
Tap
Tap and River
1:1 mixture
River
46
-------
Co liforms
Approximately 850 samples from the Baltimore system were examined for
the presence and level of the coliform group. Only 6 positive samples were
obtained with MPN/l0O values of 2.0 (4 samples) 6.0 and 33.0. Typical
colonies from EMB plates for 3 of the positive samples were tested for
indole, methyl red, VogesProskauer and Simmons citrate. Thirty colonies
were tested for each sample. All isolates from 2 of the samples gave + +
IMVIC patterns while all of the 30 isolates from the remaining sample
tested were IMVIC + + +. Because of the small number of positive samples,
no computations of correlations were attempted between coliform level and
the physical and chemical parameters of the samples.
Of the 136 samples examined from the Frederick distribution system, 4
were positive for coliforms, with MPN/l00 values of > 2,400, 2.0, 49 and 170.
All 4 of these samples came from the same sample station and represented 12%
of the samples taken from this station. Isolates from 3 of the positive
samples were tested for their IMVIC pattern. For one sample, all isolates
were + +, while another sample gave all + +. Isolates from the
third sample showed a varied IMVIC pattern, with 13, + +; 12, + + +;
7, + ; and 2, + + .
Plate Count
The effect of incubation time on the number of bacterial colonies found
on the standard plate count agar is shown in Figure 20. The results are
plotted as N/Nf X 100, where N is the number of colonies at any time t, and
Nf is the number of colonies on the terminal day. Thus the scale N/Nf X 100
is the percentage of the final count. For the 35°C data, each point is the
mean value of 37 samples, while for the 20°C data, each point is the mean
value of 35 samples. Bars represent one standard deviation around the
mean. The 35°C plate count increased with time up to 6 days (144 hours)
incubation before leveling off. The 20°C plate count increased over the 14
day period monitored. Plates were routinely counted at 48 hours and 96
hours incubation at 35°C. The 48 hour time was selected to conform with
standard practice (Standard Methods, 1975) while the 96 hour time was found
to give maximum colony development without overcrowding. It was necessary
to avoid overcrowding, since colonies were picked from the plates for
subsequent biochemical screening. The 96 hour count represented approxi-
mately 65% of the final count, as seen in Figure 20. The 9 day incubation
for the 20°C plates was also selected to avoid overcrowding and also repre-
sented approximately 65% of the final count. Complete plate count data
are found in Appendix D.
Linear Regression Analysis of Distribution System Data
Samples were collected weekly for 42 weeks (July 17, 1977 May 31,
1978) from the Baltimore distribution system and for 35 weeks (July 24,
1977 April 12, 1978) from the Frederick distribution system. The basic
data for temperature, turbidity, chlorine residual, pH, coliform, 35°C
plate count after 48 and 96 hours incubation, and 20°C plate count after 9
days incubation for each sample station are given, by week of sampling, in
Appendix D.
47
-------
120
iOO
050
0
60
z
Z 40
20
0.
1
/
o I 2 3 4 5
INCUBATION TIME
6 7 8
days
days
Figure 20.
Effect of incubation time on the number of
bacterial colonIes obtained on standard plate
count agar at 20°C and 35°C. Each point repre-
sents the mean of 35 to 37 samples, while the
bars represent 1 standard deviation around the
mean.
35°C
0
0
x
z
z
20° C
0 2 4 6 8 10 12 14
INCUBATION TIME
16
48
-------
Since the Baltimore and Frederick system differ in the type of treat-
ment and kind of chlorine residual maintained, data from the two systems
were analyzed separately. Most of the data obtained pertained to the
Baltimore system. This information from the Baltimore system was entered
into a computer and a linear regression model was utilized. The statistical
package for the social sciences (SPSS) (Nie et al., 1975) was used. The
variables entered were pH; temperature; turbidity; free chlorine concentra-
tion; 35°C, 4 day incubation plate count (PC 4); and 20°C, 9 day incubation
plate count (PC 9). Positive coliform was obtained on only 6 of 850 samples
and was not included in this analysis. The 35°C, 48 hour, plate count data
were also not included in the analysis since 93% (742 of 798) of the samples
had plate counts of less than 30/mi, and 86% showed plate counts of less
than 10/mi. For simplicity, cases where one of the above variables was
missing were omitted from subsequent analysis, resulting in a total number
of 812 cases. The correlation coefficient matrix generated for these
variables is shown in Table 10. The values for the two plate counts were
transformed into logs before analysis. All subsequent plate count data
were given in the form of log plate count. Plate count results were con-
sidered the dependent variables while the physical and chemical parameters
were considered independant variables. As shown in Table 10, significant
correlation (R 0, P = 0.001) was found for PC 4 and PC 9 versus free
chlorine concentration ( R = 0.50 and R = 0.66, respectively), and PC 4
and PC 9 versus turbidity (R = 0.34 and R = 0.29, respectively). Significant
correlation was also obtained for PC 4 versus PC 9 (R = 0.76), chlorine
concentration versus turbidity (R 0.22) and for chlorine concentration
versus temperature (R= 0.23).
In order to visualize the relationship of plate count with chemical
and physical parameters, scatter plots were constructed. Figures 21 and 22
are plots of all the log plate count values (PC 4 and PC 9) versus the free
chlorine residuals in mg/liter. The numbers plotted on these and subsequent
figures represent instances where more than one point occurs at a given log
plate count and chlorine residual value, while the stars represent indivi-
dual points. In these cases, the numbers are the number of points occurring
at a particular X and Y value. As would be expected from the values of the
correlation coefficients, considerable scatter around the regression line
was observed. The equation for the regression line shown in Figure 21 is:
log PC 4 = 1.06 (chlorine residual) + 1.25 (1)
while the equation of the regression line for PC 9 shown in Figure 22 is:
log PC 9 = 1.67 (chlorine residual) + 1.84 (2)
The 20°C, 9 day incubation plate count is more sensitive to chlorine resi-
duals than the 35°C, 4 day incubation plate count, as shown by the larger
negative slope in equation (2) above.
Scattergrains of log PC 4 and log PC 9 versus turbidity in NTU are
shown in Figures 23 and 24. The slopes of these two lines are 0.47 for PC
4 and 0.66 for PC 9. Although the data are more widely scattered than in
the case of plate count versus chlorine residual, a significant positive
49
-------
0
TABLE 10.
CORRELATION COEFFICIENT MATRIX FOR CHEMICAL, PHYSICAL AND BIOLOGICAL DATA
COLLECTED IN THE BALTIMORE WATER DISTRIBUTION SYSTEM
CORRELATiON COEFFICIENT C0MPUTA11Ct
PE&RSON
CORRELATION
COEFFICIENTS
PH TEMP
TURBID
FREECL
LOGPC.
LOGPC9
PH 1.0000 0.0431
1 0) I 812)
5=0.001 5=0.110
0.0017
1 112)
S=O.41s1
0.O5 3
I 1112)
5=0.046
0.0045
1 8121
5=0.449
0.0096
I 812)
5=0.392
TEMP 0.0431 1.0000
812) I 0)
5=0.110 5=0.001
0.0030
C 812)
S=O.466
-0.2329
1 812)
5=0.001
0.27 9
1 812)
S=O.O01
0.1915
1 812)
5=0.001
TURBiD 0.0017 0.0030
I 012) 1 812)
5=0.431 S=0.466
1.0000
1 0)
S=0.001
0.2178
1 812)
5=0.001
0.33 I 7
1 6121
5=0.001
0.2934
1 812)
5=0.001
FREECL 0.0593 0.2 29
1 612) C 1312)
5=0.040 5=0.001
0.2178
( 812)
5=0.001
1.OuOO
C 0)
5=0.001
0.4968
1 012)
5=0.001
0.6623
I 312)
S=0.001
L OGPC4 0.0045 0.2 159
812) C 812)
S=0.4 .9 =0.GO1
0.3387
1 812)
S=0.001
0.4968
I 81k)
5=0.001
1.0000
1 0)
S=0.001
0.7588
1 1312)
5=0.001
100PC9 0.0096 0.1915
1 612) I 812)
S:0.392 5=0.001
0.2934
I 612)
S=0.001
0.6623
1 612)
S0.001
0.7588
1 812)
S=0.001
1.0000
1 0)
5=0.001
ICOEFFIC1CNT / (CASES) / SIGNIrICANCE)
-------
SCAT 1 RG AM
3 .00 00
2.1000
2.4000
2.1000
U 1.4000
0
It)
>- 1.5000
0
1.2000
I-
z
0
0.9000
U i
-J
a. 0.6000
4 .
0
0 .30 0 0
0.0
(ACROSS) FREICL
1.1000 1.3000 1.5000 1.1000 1.9000
oc (DOWN) LOGPC4
0.1000 0.3000 0.5000 0.1000 0.9000
U i
3.00 00
4 .
2.1000
S *
5
0 S S
5 2.4000
2
I
5s *
*
* 2.1000
S
3 * *
* .
S S S S S
$ 3 1.8000
7* S
5 * S
S S 5 2
3* 2 S S
52 2 * 3 S 1.5000
S S 2 3 3 3
6 5 2 3 2 5 3 5
5 * 2 * 2 S * *
I7T;Ti 4 TTTT >. : . ..
0.0 0.2000 0.4000 0.6000 0.4000 1.0000 1.2.000 1.4000 1.6000 1.4000 2.0000
FREE C 4LORINE RESIDUAL mg/I
Scattergram Log 35 C plate count, 4 day incubation versus free chlorine, Baltimore.
Stars represent individual data points and numbers indicate number of coincident
data points.
Figure 21.
-------
ib0wN LOGPCO I&CROSSI F L1CL
04000 0.3000 0.3000 0.7000 0.9000 1.1000 1.3000 1.3000 1.7000 1.9000
t I I 1 I 1 1 I - I
$CAfl1 GRM OF
3.0000 0 6
46
6
0 I
6
1. 1000 4
6 I I I
I.
I II I
I I
2.4000 4
2 1
3 6 I
3 2 2
() 3 I 2 I
2.1000 44 2 2 2 2
o 3
C O I I 2 2
2 2 3
I 2 2
41.1000 I I 2 2
o 2 1 62 3
m : ; ;
0.0 0.2000 0.4000 0.6000 0.6000 1.0000 1.2000 1.4000 1.6000 1.8000 2.0000
FREE CHLORINE RESIDUAL
Figure 22. Scattergram Log 20°C plate count, 9 day incubation versus free chlorine, Baltimore.
Stars represent individual data points and numbers Indicate number of coincident data
points.
I
I
I
I
I
I
I
2
3
I
I
I
6
I
2
S
6
2
2
I
3
I
9
S
9 5
5
5
9 9
03
7
3 .0000
2 .1000
2.4000
2.1000
1.6000
I J000
1.2000
0 .9000
o ooo
0. 3000
0.0
1%)
-------
S (.AI1(R6RAM OF IOOwP4J LOGPC4 IACROSS) TUkOZO
0.1000 0.3000 0.5000 0.7000 0.90 ( 0 1.1000 1.3000 1.5000 1.7000 1.9000
I t I I I I S I I I I I I I I
3.0000 3.0000
.
0 0 0
j.1000 . 0 0 2.1000
0
. I
0 0 *
1 S S 2 S
2.4000 I 0 0 5 2.4000
0 0
0 0
S 5 0
I
2. 1000 : .: 2.1000
2
1.0000 2 5 30 0 5* 5 5 1. AOuO
4 2 5 0 5*5 *5 *
o 5 * 2 e 5 0
0 * * *0 02 *
* 0 5*0 * S S
1.5000 * 0 3 2 ee*. 2 S 5 5 1.5000
I *0*00 *22 * 0 * *2 *
000 3.2 S S 5* 0 5 2 e
30fl02 0 3 50
o. ooo z ai 2220*4 020* 0 5* 0 j
z 1 .5 .2 S 5 *22 3 2 2
0.0 5Z94 9, 95e39.6191462533494I503235Z39 7 2 S I 0 0.0
0.0 0.2000 0. o0Q 0.6000 0.0000 1.0000 1.2000 1.4000 1.6000 1.11000 2.0000
TURBIDITY NTU
Figure 23. Scattergram Log 35°C plate count, 4 day incubation versus turbidity, Baltimore.
Stars represent individual data points and numbers indicate number of coincident
data points.
-------
Sc.*7ILRGkAM OF
3.0000
2.7000
2. . O O O
o 2.1000
0
0
(J
>- i.eooo
4
0 i
1.5000
z
0
0
1 2000
w
4
-j
0.9000
C,
0
-j
0.6000
(.3000
0.0
Figure 24.
(UtJWtl) LOGPC9
0.1000 0.3000 0.5000 C ,.?000 0.0O( 0
I I 1 I *
e. 5 2 0 5 S
Z 50
0 2
700. 00 5 0
0 S 2
$ S
S * S 505 5
20 200 0005
553 S *0
S S
S
5 5 5
$ S *0
$ S S 0 00
5 5 00 5 $
2 S 2 5* $5 S $5. SO
50 5 2 5 5 5 55
5 5$ S 52
OS * 0 00 5
S * S S S
S 2 20* 2 55
07*5 5 S $0
7 2 4 05 S 52 2
2$ 2 555 55
S 5* 55 35 5
2 Se *2* S S * * S S $
$ S5 55 5 0
0 0 2 S S
S. 055 5 S 5 5 S
55055 5* $ 5
7*5 5 770 0 S 5 5 50 , 5
* 2 * *55 0__ -4(
54 $ $ 5 S
* 2 . r. S
555$ ,,i- l 5* 23 * 3
$ 55 S
5 2 5 S S
7 57 2 5 455 5*5
55 2 0*5 * 5 55
*5 ! . *5 55 2 2
5.055 5 055* 05 50
52 3 .2 25 2 S 7
2 5 035 $ 0 *53 0 50
2 7 0705 7 *5 5 5
2*20 0 S 0 S S
)39 q8qqqoyn)mqf 35.43s 9
(ACROSS) 105810
1.1000 1.3000 1.5000 1.7000
S
2
0
S
2
S
*
S
2
S
2
2
2
S
S
S
S
7 2 5
0
S
2
S
S
*
S S
0.L0t*U (J.4000 0.6000 0.5000 1.000C) (.2000 &. .O0O (.6000
TURBIDITY, NTU
Scattergram Log 20°C plate count, 9 day Incubation versus
Stars represent, individual data points and numbers indicate
data points.
1.9000
3. 00 00
2 7000
2.4000
2 1000
1.8000
1.5000
1. 2000
0. 90 00
0. 60 00
0.3000
0.0
(.8000 Z.u000
turbidity, Baltimore.
number of coincident
Ln
S
*
S
2
S
$
2
S S
S
-------
relationship was observed. It should be noted that a fairly narrow range
of turbidities was encountered in this study. Most of the samples taken
had turbidities of less than 1.2 NTU.
Figure 25 shows the relationship of free chlorine level and turbidity.
This figure was constructed to look for interaction between these two
independant variables. The correlation was found to be significant, but
the slope of 0.17 indicates that the changes in turbidity pe unit change
(1 mg/liter) of chlorine residual is small.
The greatest correlation (R = 0.76) of any of the variables was ob-
tained for PC 4 versus PC 9 as shown in the scattergram in Figure 26. The
20°C, 9 day incubation plate count consistently gave higher levels of
bacteria than the 35°C, 4 day incubation, as shown by the distribution of
points to the right of the diagonal in Figure 26.
It is apparent from previous figures that, although a linear regression
analysis does show correlation between turbidity, chlorine residuals, or
temperature versus plate counts, the use of one of the physical or chemical
parameters as a predictor of individual plate count values will fail because
of the wide scatter of the data.
In order to test the utility of the parameters in predicting mean
plate count values, log plate count data were grouped by ranges of chlorine
residuals and turbidities and the mean log plate count within each range
was calculated. The ranges used were in increments of 0.1 mg/liter for
chlorine and 0.1 NTU for turbidity. The resulting mean plate count was
plotted against the midpoint of the range. Equations for the regression
curves were calculated, using SPSS. The curves for PC 4 and PC 9 versus
chlorine residual are shown in Figures 27 and 28. Larger correlation
coefficients were obtained for the mean plate count values shown in these
figures than for the individual values shown in the previous scattergrams.
The value of R for mean log PC 4 versus midpoint of chlorine concentration
was 0.62, while the value for log PC 9 was 0.73.
The results shown in Figures 27 and 28 indicate that a linear model is
perhaps not the best choice for chlorine residual since the decrease in
log plate count seems almost exponential. This is due in large part, to the
dramatic decrease in log plate count between the chlorine ranges of 00.1 and
0.10.2 mg/liter. Many of the samples from Baltimore that fell within the
range 00.1 mgCl/l had no measurable chlorine residual. This shows that
any measurable chlorine residual at all is effective in reducing the plate
count. This effect is more clearly shown in Tables 11 and 12. These
tables si1mm rize the ranges of plate count values at varying levels of free
chlorine. For the 20°C, 9 day incubation plate count, 90% of the samples
with chlorine residuals less than 0.04 mg/liter showed plate counts greater
than 100 bacteria/mi. Of the samples with chlorine residuals of 0.05 mg/i
or greater, no more than 31% gave plate count values greater than 100
bacteria/mi. While the 35°C, 4 day incubation plate counts generally had
lower levels of bacteria, the effect of chlorine residual was still apparent.
Of the samples with chlorine residuals less than 0.04 mg/liter, 31% gave
plate counts greater than 100 bacteria/mi. For samples with chlorine
55
-------
SCAIILM(.6A$ OP $OOWNI U*SI0 *t*OSSl PRIIC*.
0.1000 0.3000 0.S000 0.7000 0.9000 1.1000 1.3000 I.S000 1.7000 1.9000
I -t t I I t t - - I I I I I I
2.0000 2.0000
S
1.6000
1.6000 S S 1.6000
3 S
1.4000 3 1.4000
S 2 I S
1.2000 I 5 2 2 2 I 1.2000
z
9 2 2 2 9 S S
1.0000 9 5 S I 4 4 3 I S 9 2 1.0000
1 4 3 3 3 6 *
0 72* 2 2 3 7
Jl 2 2 2 3 4 I
a 55 754 2 5 I I S
0.5000 9 2 2 6 2 3 9 5 I I 0.5000
0.6000 0.6000
0.4000 9 2 I 2 4 4 6 I 9 9 I 0.4000
4)126 4 o 1 I 9 2 7 2
61 2 3 3 9 41 2
3?? 6 4 1 5 2 2 3
5 7 a
0. O0 0.2.000
0.0 5. 0.0
. o 0.6000 O:B000 1.2000 1.6000 1.5000 Z.OQUO
FREE CHLORINE RESIDUAL, mη/I
Figure 25. Scattergarm Turbidity versus free chlorine, Baltimore. Stars indicate
individual data points and numbers indicate number of coincident data points.
-------
OF IDOWII ) LoGpc4 )ACROSS ) L0(.PC9
0.1500 0.4500 0.7500 1.0500 1.3500 1.6500 1.9500 2.2500 2.5500 2.8500
t t I I I I I S I I I I S
3.0000 3.0000
00 *0
2.7000 S 2.7000
..
$
* S S 0 0
0 0* S 2.4000
S
2.1000 $ . 5 S * 2.1000
U
a S
It) * I
5 5 2 5 *3
* * 5 5 S S
1.O OCs O 0 * 05 0 S 5$ * I 5 1.8000
4 0 . 2 2 *
0 * 5 * 5 2 *
S.. S *0* S
* * 5 2 * *
1.5000 7 3*2* * 0 5 * *
* 2 0 *2 * 2 2 * 5 *
S * * 5 3 22 Z5$* * 5 * * 5
z
e 5* soS 2* *
I_n 0 * * S *4 *4* * 2* 2 S 2
.1 u 1.2000 * 5 * 5 S 5 * 2 2 * 5 1.2000
5 5 5
I 5 5 *3 *4 5 * 45
$
3 5 * 5 * 5* 0
w
3 4 $ * 4* *
I -
S * 5 *
2 0 32* 20 2 5 2
S
0. 9000
0.9000
a-
5 2 S * 5 * *5555 *5
* 0 S S *
3 o 25 * 2 *47* 5 S *
0
* ________.i___b__i_i___i_ii_i
:
-J
. . ::. . . :
0. 60 00
7 0 s*$**5305 *
.1
: : ; ,.. 5;5 S
o.
0. *0 00
, . . . .. .
0.0 9 9 9 9 *7 4 5 47 0 *277*7* 2 05 2 7 0* *5 5 *0*7* 0.0
I I I I I
0.0 0.30(10 0.6000 0.9000 1.2000 1.5000 1.8000 2.1000 7.4000 2.7000 3.0000
LOG PLATE COUNT , 9 DAY, 20°C
Figure 26. Scattergraifl Log 35°C plate count, 4 day incubation versus log 20°C plate count, 9
day incubation, Baltimore. Stars indicate individual data points and numbers in-
dicate number of coincident data points.
-------
1.60
1.34
I ,
N)
4
. 1.08
I
z
0
U
0.82
00 4
-j
a-
CD
0
-j
z 0.56
4 S
0.30 ___________________________________________________
0.0 0.24 0.48 0.72 0.96 1.20
FREE CHLORINE RESIDUAL, mg/I
Figure 27. Relationship between the mean log 35°C plate count, 4 day incubation and free
chlorine residual, Baltimore.
.
.
S
.
-------
2.60
C)
0
o 2.16
(J
>-
0
0 )
- 1.72
I .-
z
0
0
l.28
z 0.84
I
S
S
0.40
0.0 0.24 0.72 0.96 1.20
FREE CHLORINE RESIDUAL, mg/I
Figure 28. Relationship between the mean log 20°C plate count, 9 day incubation and free chlorine
residual, Baltimore.
S
S
S
0.48
-------
0
TABLE 11.
DISTRIBUTION OF RANGES OF PLATE COUNT VALUES AFTER 4 DAY INCUBATION AT 35°C FOR
VARYING RANGES OF FREE CHLORINE RESIDUALS. DATA ARE FROM 21 SAMPLING SITES IN THE
BALTIMORE, MARYLAND WATER DISTRIBUTION SYSTEM SAMPLED WEEKLY FOR A 42 WEEK PERIOD
Plate
Count
colonies/mi
% of
samples within
indicated
of
ranges of plate count values at varying
free chlorine residuals in mg/liter.
ranges
0.00
0.04
0.05
0.20
0.21
0.40
0.41
0.60
0.61
0.80
0.81
1.00
1.01
1.20
All Cl
Residuals
<1.0
0.. 6
9
15
13
21
21
20
13
110
19
52
52
61
67
60
60
51
11100
49
30
27
25
9
19
20
27
1011000
26
8
4
1
2
0
0
8
100110000
5
1
1
0
0
0
0
1
Total %
99.6
100
99
100
99
100
100
100
Total //
samples
174
102
92
189
174
68
25
824
-------
TABLE 12. DISTRIBUTION OF RANGES OF PLATE COUNT VALUES AFTER 9 DAY INCUBATION AT 20°C FOR
VARYING RANGES OF FREE CHLORINE RESIDUALS. DATA ARE FROM 21 SAMPLING SITES IN THE
BALTIMORE, MARYLAND WATER DISTRIBUTION SYSTEM SAMPLED WEEKLY FOR A 42 WEEK PERIOD
Plate
Count
colonies/ml
% of
samples within
indicated
of
ranges of plate count values at varying
free chlorine residuals in mg/liter.
ranges
0.00
0.04
0.05
0.20
0.21
0.40
0.41
0.60
0.61
0.81
0.81
1.00
1.01
1.20
All Cl
Residuals
<1.00
0
6
11
9
22
33
22
12
110
1
33
38
54
57
48
39
38
11 100
9
29
37
33
19
18
39
24
1011000
55
27
13
3
2
1
0
18
100110000
35
4
1
0.5
0
0
0
8
Total %
100
99
100
99.5
100
100
100
100
Total II
Samples
171
102
90
188
175
67
18
811
-------
residuals greater than 0.05 mg/liter, no more than 9% gave plate counts
greater than 100 bacteria/mi.
The mean log plate count was plotted against midpoints of the ranges of
turbidities in Figures 29 and 30. It was apparent that, even over a rela-
tively narrow range of turbidities, increasing turbidity was associated
with an increase in the plate counts. The R value for PC 4 was 0.73, while
the R value for PC 9 was 0.88.
In the analysis of data a multiple linear regression program (SPSS)
was used to evaluate the relative importance of the independent variables:
chlorine residual, turbidity, and temperature in determining log PC 4 or
log PC 9. Independent variables were divided into ranges: chlorine residual
in increments of 0.1 mg/liter from 0 to 1.2 mg/liter, turbidity values in
increments of 0.1 NTU from 0 to 1.3 NTh, and temperature in increments of
2.5°C from 0 to 30°C, and midpoints of the ranges of chlorine residual,
turbidity and temperature were used. Dependent variables log PC 4 and log
c 9 were then grouped for each range of chlorine residual, turbidity and
temperature values. Thus, for example a group of plate count values was
associated with a chlorine residual midpoint of 0.15 mg/liter, a turbidity
midpoint of 0.15 NTU, and a temperature midpoint of 1.25°c. All possible
regressions were run including 1, 2, or 3 of the independent variables in
varying orders. Results given in Table 13 show the independent variables
ranked in decreasing order of importance for the 35°C plate count. Two
methods were used to rank the independent variables, the change in R square
accompanying the introduction of the variable into the equation (Draper &
Smith, 1966) and the use of standardized regression coefficients (Nie et al .,
1975). Table 13 indicates that the R square change associated with chlorine
was 0.22, while the change for turbidity and temperature was much smaller,
0.06 and 0.03 respectively. The change in R square indicates that the
amount of variability in PC 4 accounted for by the regression curve increases
as turbidity and temperature were added, but the magnitude of the change
indicates that turbidity and temperature were of less importance than
chlorine residual. The multiple R for all three independent variables was
0.56 ( R square = 0.32).
The use of standardized regression coefficient (Beta) enables compari-
Sons of regression coefficients and independent variables with different
units (NTIJ, mg/liter and °C) to be made. The magnitude of the standardized
regression coefficient reflects the relative importance of the associated
variable. Chlorine residual was found to have the greatest effect on PC 4
(Beta = 0.38), followed by turbidity (Beta = 0.26) and temperature (Beta =
0.19). The equation of the regression curve is:
log PC 4 = 0.67 0.93 (Cl residual, mg/liter) + 0.34 (turbidity NTU) +
0.02 (temperature, °C)
All the regression coefficients were found to be significant at the 1% level
(B # 0).
Similar data for PC 9 are shown in Table 14. Again, chlor ne residual
was found to have the greatest effect (Beta = 0.59), followed by turbidity
62
-------
1.65
1.42
C-,
0
I L)
I )
>-
4
c 1.19
F-
0
o 0.96
IL l
F-
4
-J
(9
0.73
z
4
L i i
0.50
0.0
Figure 29. Relationship
Baltimore.
S
0.26
0.78
TURBIDITY, NTU
1.04
1.30
between the mean log 35°C plate count, 4 day incubation and turbidity,
IJ
.
S
0.52
-------
I I I
I
2.32
2.14
0
0
0
>-
1.78
1 .60
z
0 0
oI.42
U i
I
4
-j
0
-J.
4
O.88
S
0.70 I U
0.0 0.26 0.52 0.78 1.04 1.30
TURBIDITY, NTU
Figure 30. Relationship between the mean log 20°C plate count, 9 day incubation and turbidity,
Baltimore.
U I U I I
-------
TABLE 13. MULTIPLE LINEAR REGRESSION
TURBIDITY, AND TEMPERATURE
MODEL FOR THE 35°C, 4 DAY PLATE COUNT WITH FREE CHLORINE,
VARIABLES ADDED SEQUENTIALLY
+ B = regression coefficient
Beta = standardized regression coefficient
** significant at 1% level
0
U i
Dependent variable
Variable
log PC 4
multiple R
R Square
R
Square
Change
Simple
R
B+
Beta
Std. Error
B
F
free chlorine
.47
.22
.22
.47
.93
.38
.08
154.2**
turbidity
.53
.28
.06
.34
.34
.26
.04
78.O**
temperature
.56
.32
.03
.27
.02
.19
.003
39.8**
constant
.67
-------
TABLE 14. MULTIPLE LINEAR REGRESSION MODEL FOR THE 20°C, 9 DAY INCUBATION PLATE COUNT WITH
FREE CIll .ORINE, TURBIDITY AND TEMPERATURE VARIABLES ADDED SEQUENTIALLY
Dependent variable
log
PC 9
Variable
multiple
R
R
Square
R
Square
Change
Simple
R
B+
Beta
Std. Error
B
F
free chlorine
.64
.41
.41
.64
2.02
.59
.09
453 9**
turbidity
.66
.43
.03
.29
.31
.17
.05
41.3**
temperature
.66
.44
.003
.19
.009
.06
.004
4 3*
constant
1.75
+ B = regression coefficient
Beta = standardized regression coefficient
** Significant at 1% level
* Significant at 5% level
-------
(Beta = 0.17) and temperature (Beta = 0.06). The value for the multiple
correlation coefficient 0.66 (R square = 0.44) was higher than that observed
for PC 4. Generally, PC 9 was found to be more dependent on chlorine
residual and less dependent on temperature. Temperature was not found to
be significant at the 1% level for PC 9, but was significant at the 5%
level. The equation of the regression curve for PC 9 is:
log PC 9 = 1.75 2.02 (Cl residual, mg/liter) + 0.31 (turbidity, NTU) +
0.009 (temperature, °C)
A total of 123 samples were taken from 4 sampling stations in the
Frederick water distribution system. The results were treated similarly to
those from the Baltimore system, except that all calculations were done
manually using a Texas Instrument TI59 programmable hand calculator.
Complete data for these samples are given in Appendix D. The correlation
coefficient matrix for various parameters measured is given in Table 15.
Significant positive correlation CR 0 p = 0.001) was found between the
two plate counts 35°C, 4 day incubation (PC 4), and 20°C 9 day incubation
(PC 9), and turbidity. Significant negative correlation CR 0 p = 0.05
to p = 0.001) was found between the two plate counts and free and total
chlorine levels.
The greatest correlation, R = 0.92, was obtained between the 35°C, 4
day plate count and the 20°C, 9 day plate count. The equation for the
regression line for these variables is:
PC 9 = l.02(PC 4) + 0.07.
The slope of the line indicates that the bacterial counts obtained at 35°C
were equal to those obtained at 20°C, as opposed to the Baltimore system
where the 20°C counts were consistently higher.
The effect of turbidity on the mean log plate count values is shown in
Figures 31 and 32. The mean log plate counts for ranges of turbidity in
increments of 0.2 NTtJ were calculated and their values were plotted against
midpoints of the turbidity ranges. As was observed f or the Baltimore
system, the mean plate count values showed higher correlation with turbidity
than did the individual plate count values. The R value for the mean 35°C,
4 day plate count versus turbidity was found to be 0.89, and the equation
for the line shown in Figure 31 is:
log PC 4 = 0.61 (turbidity) + 0.46
The R value for the mean 20°C, 9 day plate count is 0.87, and the equation
for the line shown in Figure 32 is:
log PC 9 = 0.59 (turbidity) + 0.61
In Figures 33 and 34, mean log plate count values were plotted against
midpoints of ranges of free and total chlorine levels. These ranges were
0.1 mg/ liter for free chlorine and 0.2 mg/liter for total chlorine.
Again, higher correlations were obtained when mean values, rather than the
67
-------
TABLE 15. CORRELATION COEFFICIENT MATRIX FOR CHEMICAL, PHYSICAL AND
BIOLOGICAL DATA COLLECTED IN THE FREDERICK WATER DISTRIBUTION
SYSTEM
Turbidity
Free Cl
Total Cl
Log PC 4
Log PC 9
Turbidity
1.0
.04
.07
.40***
43***
Free Cl
1.0
.27**
.24**
.20*
Total Cl
1.0
.41***
43***
Log PC 4
1.0
.92***
Log PC 9
1.0
* significant at 95% level
** significant at 99% level
*** significant at 99.9% level
68
-------
2.2
1.0 1.5
Turbidity
Figure 31.
Relationship between the mean log 35°C plate count, 4 day
incubation and turbidity, Frederick.
.
1 -
z
0
0
0
Ld 0
-
0.
z
ILl
S
I.e
1.4
I.0
0.6
0.2
0
S
S
S
0
0.5
2.0
NTU
2.5
3.0
69
-------
I .-
z
0
cJ
-
z
w
2.2
1.8
1.4
1.0
0.6 r
0.2
01 I
0 0.5 1.0 L5 2.0 2.5 3.0
Turbidity . NTU
Figure 32. Relationship between the mean log 20°C plate count, 9 day
incubation and turbidity, Frederick.
.
.
. .
70
-------
3.0
.
S
o
FREE
0.2 0.4 0.6 0.8 1.0
1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2
CHLORINE RESIDUAL, mg/I
Figure 33.
Relationship between the mean log 35°C plate count, 4 day incubation, and
the free fraction and the total chlorine residual, Frederick.
z 2.5
0
U
U
IL l.
I )
0.>
-Jt
z
4
I L l
0.5
I -i
1.0
0
0_
0
-------
3.0
.
2.5
.
0 2.0
TOT
IS .
z 0 0
4
Id 1.0
p..) . .
0.5
0 . I I p p p p p p p p p p
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2
CHLORINE RESIDUAL, mg/I
Figure 34. Relationship between the mean log 20°C plate count, 9 day incubation,
and free fraction and the total chlorine residual, Frederick.
-------
individual values were considered. It is important to note that the Freder-
ick system employs the chiorineanimonia process with a resulting high total
chlorine and low free chlorine residual. Thus, the curves shown for free
chlorine residuals are not for free chlorine alone, but for the free frac-
tion of a relatively high total chlorine residual. The free and total
residuals were found to be correlated with each other with an R value of
0.27. The equation for the free chlorine line for PC 4 in Figure 33 is:
mean log PC 4 = 1.61 (free Cl) + 1.72
while the equation for the total chlorine line is:
mean log PC 4 = 0.39 (total Cl) + 2.23
with R values of 0.90 and 0.52, respectively. For the 20°C, 9 day plate
count shown in Figure 34, the equation for the free chlorine line is:
mean log PC 9 = 1.33 (free Cl) + 1.76
for the total chlorine line:
mean log PC 9 = 0.47 (total Cl) + 2.50
with R values of 0.85 and 0.65, respectively. In both instances, the
mean log plate count shows a greater dependence, as evidenced by the larger
negative slope on the free chlorine fraction of the total chlorine residual
than the total residual. The large difference in mean plate count values
between the 0 0.1 mg/liter range and 0.11 0.2 mg/liter range for free
chlorine, which appeared in the Baltimore system, was not found for the
Frederick samples. The lack of agreement in these results between the two
systems may be due to two factors. Many of the samples from Baltimore that
fell within the range 0 0.1 mg/liter had no chlorine residual, while most
of the Frederick samples in this range had some apparent measurable free
chlorine residual. Also, the Frederick samples had a relatively high total
chlorine residual, which was absent in the Baltimore samples.
Microbial Differentiation
A total of 6506 colonies were picked from the standard plate count
agar incubated at 20°C and 35°C and tested for catalase activity, oxidase,
motility, indole production, anaerobic growth and acid production from
glucose (aerobic and anaerobic). The isolates were assigned to arbitrary
numbered groups on the basis of the pattern obtained with these seven
tests. A total of 43 different groups were found within the 6506 isolates.
Gram reaction, nitrate reduction, citrate utilization, and growth on Mac
Conkey agar were determined for a portion of the isolates in each group to
obtain further information and to evaluate homogeneity within the group.
The 20 major groups, comprising 90% of the total isolates tested, are shown
in Table 16. The groups are ranked in decreasing order of predominance at
35°C. A further description of the groups follows.
73
-------
TMLE 16. MAJOR BIOCIIEIIICAL GROUPS ISOLATED FROM PLATE COUNTS FROM THE BALTIMORE AND
ARVTA .$ DIST TmTTTION SY TT M
6
9
26
3
24
17
10
18
22
5
13
16
28
6
14
11
27
I
30
2
χ
+
+
+
+
+
+
+
+
+
+
+ +
+
+
+ +
+
+ +
+ +
+
χ
+ +
+
+ +
+ +
+ +
+ +
+
+
740 (21.3)
963 (27,8)
185 ( 5.3)
+ 217 ( 6.3)
+ 181 ( 5.2)
170 ( 4.3)
+ + 38 ( 1.1)
χ -. 120(3,5)
+ 167 ( 4.8)
60(1.7)
+ 19( .5)
13( .4)
χ 33(1.0)
45(1.3)
44(1,3)
+ * 58 ( 1.7)
35(1.0)
+ 31( .9)
5( .1)
+ 34(1.0)
.-
-
& -
F icu1totive
Acid from
Acid frcm
20°C number
350
number
Group
Anaerobe
Glucose Glucose
Anaerobically Aerobically
Catalase
Activity
Oxidase
P oti1ity
Indole
Isolated
of Total
(7.
Isolated
(% of Total)
FREDERICK,
+ +
+
+
+
+
+
+ +
+
+ +
+ +
+ +
+
+ +
+ +
+
598
415
212
192
184
162
155
98
97
83
67
65
64
63
52
48
46
37
32
25
(19.7)
(13.7)
( 7.0)
( 6.3)
( 6.1)
( 5.3)
( 5.1)
(3,2)
( 3.2)
( 3. 1)
( 2.2)
( 2.1)
( 2.1)
( 2.1)
( 1.7)
( 1.6)
( 1.5)
( 1.2)
( 1.1)
C .8)
TOTAL 3158 (91.1) 2695 (89.1)
-------
Gram negative aerobic norisaccharolytic rods
Group 8 Gram stains were performed on 152 isolates in group 8, of
which 144 (95%) were Gram negative rods, 5 (3%) were Gram positive rods and
3 (2%) were Gram positive cocci. Yellow pigmentation was common within
group 8, with 38% of the isolates at 20°C and 50% of the isolates at 35°C
having this characteristic. The results for the additional tests for group
8 were as follows:
nitrate growth on citrate number obtained/number tested %
reduction MacConkey utilization
59/87 (68)
+ 16/87 (18)
+ + 6/87 (7)
+ χ + 6/87 (7)
Group 8 appears to be fairly homogeneous, with 68% of the members of this
group showing one pattern on the three tests.
Group 9 Group 9 is composed predominantly of Gram negative rods,
with 190 (93%) of the isolates examined falling into this category while 8
(4%) were Gram positive cocci and 6 (3%) were Gram positive rods. On the
basis of the three additional tests, this group was also fairly homogeneous,
as shown below:
nitrate growth on citrate number obtained/number tested %
reduction MacConkey utilization
121/156 (78)
+ + + 13/156 (8)
+ + 11/156 ( 7)
+ 7/156 ( 4)
+ + 3/156 (2)
+ 1/156 ( 1)
83% of the isolates at 20°C were yellow, while 51% at 35°C were yellow.
Group 3 Of the 83 isolates in group 3 examined for Gram stain, 76
(92%) were Gram negative rods and 7 (8%) were Gram positive rods. Yellow
pigmentation was less prevalent in this group, with 20% of the isolates at
20°C and 11% at 35°C showing this pigmentation. Three patterns were obtained
with the three additional tests, as shown below. The triple negative
pattern was again the most prevalent, with 67% of the isolates examined in
group 3 showing this pattern:
75
-------
nitrate growth on citrate number obtained/number tested
reduction MacConkey utilization
46/69 (67)
+ 15/69 (22)
+ + 8/69 (11)
Group 18 Since this group composed a smaller fraction of the total
number of isolates, fewer members of this group were examined. 28 isolates
were Gram stained, of which 24 (86%) were Gram negative rods, 3 (11%) were
Gram positive rods and 1 (3%) was a Gram positive coccus. Considerable
heterogeneity was found for nitrate reduction, growth on MacConkey agar and
utilization of citrate. 63% of the isolates at 20°C, and 86% of the isolates
at 35°C demonstrated yellow pigmentation.
nitrate growth on citrate number obtained/number tested
reduction MacConkey utilization
7/12 (58)
+ + 4/12 (33)
+ + + 1/12 (9)
Although positive identification of bacteria in these groups cannot be
made on the basis of the limited number of tests utilized, a tentative
identification is possible. Possibilities for groups 8, 9, 3 and 18 include
the Pseudomonadaceae, Flavobacterium, Alcalig-enes, and !foraxella.
Gram negative facultative nonsaccharolytic rods
Group 26 Group 26 is composed of 95% (38/40) Gram negative rods and
5% (2/40) Gram positive rods. Approximately half of the isolates In this
group were pigmented yellow, 55% at 20°C and 512 at 35°C. Results of
nitrate reduction, growth on MacConkey and citrate utilization were as
follows:
nitrate growth on citrate number obtained/number tested
reduction MacConkey utilization
23/27 (85)
+ 4/27 (15)
Group 24 This group was composed almost entirely of yellow pigmented
Gram negative rods. Of the 65 isolates examined for Gram stain 64 (98%) were
Gram negative rods and 1 (2%) was a Gram positive rod. 78% of the isolates
at 20°C and 84% at 35°C showed yellow pigmentation. This group was homo-
geneous with respect to nitrate reduction, growth on MacConkey and citrate
utilization with the triple negative pattern predominant.
76
-------
nitrate growth on citrate number obtained/number tested %
reduction MacConkey utilization
47/57 (82)
+ + + 4/57 (7)
+ 3/57 (5)
+ 1/57 (2)
+ χ 2/57 (4)
Group 17 Group 17 is similar to group 24 in that many of the isolates
showed yellow pigmentation, 81% at 20°C and 63% at 35°C. 91% of the isolates
(86/95) were Grain negative rods, 5% (5/95) were Gram positive cocci and 4%
(4/95) were Gram positive rods. The results for nitrate reduction, growth
on MacConkey, and citrate utilization indicate that this group is homogeneous
with respect to these tests.
nitrate growth on citrate number obtained/number tested %
reduction MacConkey utilization
72/81 (89)
+ 5/81 (6)
+ 3/81 (4)
+ + + 1/81 (1)
Group 22 Group 22 contained 98% (50/51) Gram negative rods and 2%
(1/51) Grain positive rods. This group differed from the other 3 in this
category in that it contained a low percentage of yellow pigmented colonies,
45Z at 20°C and 26% at 35°C and showed more diversity in the three additional
tests run.
nitrate growth on citrate number obtained/number tested %
reduction MacConkey utilization
16/26 (61)
+ 9/26 (35)
+ 1/26 (4)
Majority of bacteria in groups 26, 24, 17 and 22 were consistent with the
biochemical characteristics of the FlavobaCteriUlfl.
77
-------
Gram positive or ne&ative aerobic saccharolytic rods- -
Groups 5, 6, 1 and 2 The aerobicsaccharolytic category contained
both Gram positive and Gram negative rods and a low percentage of pigmented
colonies as shown below:
group Gram reaction % yellow colonies
positive rod negative rod 20°C 35°C
5 6 8 22 10
6 7 5 27 11
1 21 7 0 0
2 9 2
In addition, 2 Grain positive cocci were obtained, 1 in group 5 and 1 in
group 6. Since these 4 groups accounted for only 5.8% of the total number
of isolates they were not tested for nitrate reduction, growth on MacConkey
and citrate utilization. Gram positive organisms within this category show
charactertistics consistent with the bacillus group, while the Gram negative
organisms can be tentatively identified as Pseudomonadaceae.
Gram negative facultative saccharolytic rods- -
Groups 10, 11 and 27 Isolates in these groups are characterized by
positive reactions on most of the biochemical test runs. A total of 46
isolates were examined for Gram reaction and morphology; 31 in group 10, 12
in group 11, and 3 in group 27. All were Gram negative rods. Yellow
pigmentation was generally absent, 0% at 20°C and 4% at 35°C for group 10,
9% at 20°C and 0% at 35°C for group 27, and 0% for group 11 at both tempera-
tures. Nitrate reduction, growth on MacConkey and citrate utilization were
done on 11 isolates in group 10. All 11 isolates were positive on these
three tests. These organisms can be tentatively identified as Aeromonas.
Facultative saccharolytic microorganisms
Groups 13, 16, 28 These groups differ from the preceding groups 10,
11 and 27 in that they contain a higher percentage of Gram positive orga-
nisms.
group Gram negative rod Gram positive rod Gram positive coccus
13 2 2 1
16 10 3 13
28 11 0 6
Yellow pigmentation within groups 13, 16 and 28 varied from 0 to 15%. Pos-
sible identification for the Gram positive coccus is staphylococcus, while
the Gram positive rods may be tentatively identified as bacillus and the
Gram negative as Entero.bacteriaceae.
78
-------
Distribution of Microorganisms by Sampling SitesThe 20 major groups
shown in Table 16 are ranked in the order of predominance at 35°C. The
trend obtained at 20°C was generally the same as is also shown in Table 16.
Groups 8 and 9 were isolated in the greatest number, with 49.1% of the total
isolates at 20°C and 33.4% of the total isolates at 35°C belonging to these
two groups.
Data shown in Table 16 are broken down by station in Appendix E.
This appendix gives the number of isolates in each group and the frequency
of isolation of each group at each station. This information was used to
generate an index of the relative importance of each group at each station,
using the following equation:
100
I=FXNX( )
F xN
max max
where:
1 is the index
F is the frequency of isolation of the group as a fraction of 1.0
N is the number of isolates in the group
N is the number of isolates in the most prevalent group of any given
max
station
F is the frequency for N
max max
It can be seen then when N = Nmax and F = Fmax, then I = 100. The index,
then, is simply the product of the number of isolates and the frequency, nor-
malized to 100. The index is given for each of the groups at each station in
Figures 35 through 42. Stations 1 and 4 are in the Frederick distribution
system, while the remaining stations are in Baltimore. Station 1 contributed
many of the facultative, saccharolytic organisms (groups 10, 11, 27, 13, 16
and 28) encountered in this survey, Figure 35 shows that while group 3 was
predominant at 35°C at station 1, group 10 had an index close to 100 and
groups 13 and 16 also had fairly high indices. Of the total number of
isolates in groups 10, 13, and 16 at 35°C, 40%, 72% and 66%, respectively,
came from station 1. Although the indices for groups 11, 27 and 1 were low
because of a low number of isolates, the contribution of station 1 was high
for these groups at 35°C with 44%, 76% and 46% of the total isolates re-
spectively. Group 10 was found only at 3 stations, number 1, 27 and 44,
and was obtained primarily at 35°C. The occurrence of group 27 paralleled
that of group 10, although at much lower levels. For the 20°C isolates at
station 1, groups 3 and 8 were predominant. Figure 36 gives the indices
for station 4, f-he other Frederick station. Groups 8 and 9 were predominant
at both temperacures. The remaining Figures 39 through 42 show the fre
quencylevel index for the Baltimore stations. Generally, 2 to 4 groups
predominate at each station at both temperatures. Although predominant
79
-------
(00
x
w
0
z
ir
U i
D
z
U
zt 0
Ui
c
Ui
60
40
20
BIOCHEMICAL GROUP
Figure 35. Relative occurrence of the different biochemical groups, as
shown by the frequencynumber index, at station 1 in the
Frederick distribution system.
20°C
80
60
40
20
80
350 C
0
n nHn
8 9 26 3 24 (7 10 18 22 5 13 16 28 6 (4 I I 27 I 30 2
80
-------
l00
BIOCHEMICAL
Figure 36.
Relative occurrence of the different biochemical groups, as
shown by the frequencynumber Index, at station 4 In the
Frederick distribution system.
80
60
40
20
0
20°C
U i
0
z
Ui
z
I 00
>-
C-)
2
Ui
D
a
Ui
80
40
20
35°C
0
3 2417 $0 18225 1316286141127 I 302
GROUP
81
-------
100
80
60
40 20°C
z
20
L i i o_ r,fli 1 flrt
100
C-,
Z 80
l ii
D
L i i
40 35°C
20 11
8 9 26 3 24 17 10 18 22 5 3 16 28 6 14 Ii 27 I 30 2
BIOCHEMICAL GROUP
Figure 37. Relative occurrence of the different biochemical groups, as
shown by the frequencynumber index, at station 27 in the
Baltimore distribution system.
82
-------
100
80
60
X 40
U i
z
20
0
m
z tOO
0
z 80
Ui
C
60
40
20
BtOCHEMICAL GROUP
Figure 38. Relative occurrence of the diUerent biochemical groups, as
shown by the frequencynumber index, at station 34 in the
Baltimore distribution system.
0
200 C
35°C
8 9 26 3 24 17 JO 18 22 5 13 16 28 6 14 I I 27 I 30 2
83
-------
100
80
60
4Q. 20°C
z
20
w
0-.- 11
z
> . 100
C-)
z
U i
a
U i
(K
U-
40 35°C
2fl ________
8 9 26 3 24 17 10 18 22 5 3 16 28 6 14 II 27 I 30 2
BIOCHEMICAL GROUP
Figure 39. Relative occurrence of the different biochemical groups, as
shown in the frequencynumber index, at station 37 in the
Baltimore distribution system.
84
-------
100
80
60
40
20
0
LU
0
z
LU
z
C.)
z
LU
a
LU
U-
Figure 40.
tOO
80
BIOCHEMICAL GROUP
Relative occurrence of the different biochemical groups, as
shown by the frequencynumber index, at station 43 in the
Baltimore distribution system.
20° C
60
20
350 C
0
8 9 26 3 24 17 tO 18 22 5 13 16 28 6 14 U 27 1 30 2
85
-------
tOO
80
60
U i
z40-
20
Ui
D
z
C-)
z
Ui
D
o 80
Ui
60
35°C
40
20H
8 9 26 3 24 17 10 18 22 5 13 16 28 6 4 II 27 I 30 2
BIOCHEMICAL GROUP
Figure 41. Relative occurrence of the different biochemical groups, as
shown by the frequencynumber index, at station 44 in the
Baltimore distribution system.
86
-------
100
80
60
U i
C 40 20°C
z
20
UJ
0 __ rlr-i fa
z
>- )00
C-,
z
U i
80
Ui
u 60
40 35°C
20
flri
8 9 26 3 24 17 10 lB 22 5 13 16 28 6 14 II 27 I 30 2
B OCHEM CAL GROUP
Figure 42. Relative occurrence of the different biochemical groups, as
shown by the frequencynumber index, at station 48 in the
Baltimore distribution system.
87
-------
groups vary in biochemical characteristics from station to station, they
were generally the nonsaccharolytic organisms.
88
-------
SECTION 7
DISCUSSION
HOLDING TANK AND RESERVOIR STUDIES
Simulated Contaminant
Unfiltered raw sewage was used as the contaminant base for the holding
tank and reservoir studies to provide a source of chlorine demand since raw
sewage has often been implicated in post treatment contamination of water
distribution systems. For the holding tank studies, the raw sewage was
autoc.iaved and stored for use to provide reproducible data and thereby
to minimize confounding effects of variations in the chemical, physical and
biological qualities of fresh samples of raw sewage. After minor changes
upon sterilization, the chemical, physical and biological parameters (in-
cluding chlorine dosage required for breakpoint) were stable for up to 30
days. While the autoclaved raw sewage seeded with the test microorganisms
was artificial, the data obtained in the laboratory holding tank studies did
provide a firm data base for subsequent comparison. Reservoir studies uti-
lized raw unfiltered sewage from Fort Neade sewage treatment plant number
2. This sewage was not autoclaved and was seeded with f2 bacterial virus.
While data from the reservoir studies were more variable, it was noted that
naturally occuring coliforins were more resistant to chlorine than the
freshly isolated member of the coliform group used in the holding tank
studies.
Mixing and Flow Regimen
Holding tank studies were of completely mixed systems without additional
inf lows and represented one of the worst contamination conditions that might
be encountered in a water supply system. The holding tank studies were de-
signed to provide an estimate of the strength and volume of contaminant that
can be neutralized by the chlorine residuals under the experimental con-
ditions, the relative survival of test microorganisms, and the relative effi-
ciencies of the types of chlorine residuals. The reservoir studies provided
information of the effect of added flow. Since the reservoir system was
found to be completely mixed during the draw and fill operation, the infor-
mation obtained would be more indicative of small storage tanks and reser-
voirs rather than larger units where complete mixing may not occur In the
draw and fill operation not only did agitation occur, but fresh disinfectant
was also introduced to neutralize the contaminant.
89
-------
Microbial Inactivation
The inactivation of microorganisms in water with chlorine is influenced
by pH, temperature, disinfectant concentration, and by chlorine consuming
interfering substances. The efficiency of chlorine residuals in the water
distribution system, when challenged with a contaminant, was similarly
dependent upon these same factors. The water in most municipal distribution
systems is slightly alkaline due to the addition of lime at the clear well
for corrosion control. Experiments were, therefore, conducted at pH 8 to
reflect the pH of the water in the distribution system. At pH 8, the
predominant species of free chlorine is hypochlorite ion and the predominant
species of combined chlorine is monochioramine.
Microorganisms in sewage introduced as contaminant in water can be neu-
tralized by the residual chlorine. An estimate of the amount of sewage that
can be added to tap water containing free chlorine residual with assurance of
rapid microbial inactivation can be calculated from the chlorination break-
point of the contaminant. For sewage with a breakpoint of 100 mg/liter, 1%
by volume is required to consume 1 mg/liter free chlorine in tap water.
Since free chlorine has been shown to be an effective bactericide and yin
cide, rapid inactivation can be expected when a free chlorine residual is
present. The autoclaved raw sewage used in these experiments had a chlorina-
tion breakpoint above 100 mg/liter (150270 mg/liter). Free chlorine was,
therefore, generally not detected 120 minutes after the addition of 1%
sewage to tap water with an initial 1 mg/liter free chlorine residual. Only
when the challenge reached 5% did the 1. mg/liter free chlorine residual fail
to provide at least 90% inactivation of bacteria and poliovirus. Longer
contact times were required for equivalent bacterial inactivation when the
initial chlorine residual was the combined form, while equivalent viral
inactivation was rarely achieved with the combined residual. In reservoir
studies, where the chlorine was replenished, greater inactivation was ob-
served at higher sewage contamination levels.
The species of chlorine present in the distribution system decidedly
affects the residual performance. A free chlorine residual affords more
protection than an equivalent level of combined chlorine under the same en-
vironmental conditions. Free chlorine was a more potent and faster acting
bactericide and .viricide for each of the conditions of pH, temperature and
sewage challenge. In addition, a free chlorine residual can serve as a
marker for contamination, since free chlorine will react rapidly with
contaminant material. In a system where free residual chlorine is normally
maintained, the absence of a free residual is evidence that chlorine de-
manding substances may have entered the system. Chemical results obtained
in these experiments indicate that a total chlorine residual is present
even after the addition of sizeable amounts of contaminant so that the
detection of a combined chlorine residual does not assure water potability.
The relative inefficiency of a combined chlorine residual in protecting
against contaminatory materials, and its failure to act as a marker
indicates that the addition of ammonia to create chloramines purposely is
contrary to good public health practice.
90
-------
It is important to emphasize that the use of free chlorine as a marker
or flag is heavily dependent upon the ability to measure free chlorine in
the field and on the chlorine residual history in the distribution system.
Despite the existence of numerous color tests and field procedures for the
determination of chlorine, a reliable, sensitive and specific test for free
available chlorine is not yet available. Cooper et al. (1974) compared
chlorine determinations by the modified orthotolidinearsenite, stabilized
neutral orthotolodine (SNORT), leuco crystal violet, N, Ndiethylpphenylene
diamine (DPD) and syringaldazine (FACTS) tests. In the hands of operators,
all except syringaldazine, yielded false positive readings for free chlorine.
The FACTS procedure was however, the least sensitive of the methods tested.
DPD has since been modified to the DPD steadiFAC by the addition of thioace
tamide to enhance free chlorine specificity, (Palm, 1978) and FACTS has
been modified to increase sensitivity (Cooper et al., 1975). The presence
or absence of free chlorine is difficult to interpret unless the chlorine
residual history at a given sample station is known. Several stations in
the Baltimore City distribution system consistently have zero free chlorine
in late summer months. The absence of free chlorine at these stations at
this time of year does not suggest any post treatment contamination. The
conspicuous absence of free chlorine at a station where free chlorine was
continually observed should, however, deserve serious attention.
The free chlorine residual is more difficult to maintain than a
combined chlorine residual. Converting a distribution system to free
chlorine requires considerable effort and patience. Several months or
years at elevated chlorine levels are often required to push a free
chlorine residual into the distribution system. (Umbenhauer, 1959; Buelow
and Walton, 1971). A free chlorine residual is sometimes impossible to
maintain in systems where excessive corrosion, tuberculation and scaling
are found.
The free chlorine residual may contribute to the formation of chlori-
nated organics in low concentrations. The formation of chloroform and
other trihalomethanes (THMs) are dependent on the presence of free chlorine.
The role of the distribution system on the THM formation, however, remains
to be evaluated.
In this study several test organisms were simultaneously exposed to in-
activating conditions, so that comparisons of the susceptibilities could be
made. The coliform organism, S. typhirnurium, and S. sonnei were inactivated
at the same rate, but poliovirus 1 was more resistant and f2 the most
resistant. Reductions of poliovirus to the sensitivity limit of the assay
did occur under some conditions, but similar inactivation of the f2 bacterial
virus was rare. Thus, while bacterial inactivation may be achieved under
many conditions, infectious viral particles could be carried to the consumer.
An organism similar in resistance to f2 would only be inactivated where the
level of introduced contaminant was small and free chlorine was present.
Combined chlorine residuals were relatively poor viricides.
Little growth was observed in any of the test microorganisms in test
conditions. The extended time studies suggest that the trend on prolonged
91
-------
storage was further dieaway. However, samples that contained high levels
of sewage, where little if any inactivation occurred, occasionally yielded
increases in bacterial numbers as did some of the dechlorinated controls.
Ideally, the disinfectant residual should protect against infectious
microorganisms up to the point where the contamination becomes visible to the
consumer. This criterion was met, for bacterial contamination, by an initial
1 mg/liter free chlorine residual. Protection was conferred up to the
addition of 1% sewage, at which point the water has a noticeable turbidity.
An initial 1 mg/liter combined chlorine residual required much longer
contact time for inactivation. This would allow for more widespread
distribution of the infectious material. An initial 0.2 mg/liter free
chlorine residual was effective against contamination of sewage level of
0.1%, which is not readily noticed. An initial 0.2 mg/liter combined
chlorine residual was totally ineffective when sewage contamination level
was even as low as 0.01%.
Data reported in this study may be used to estimate the protection af-
forded by the maintenances of chlorine residuals in water distribution
systems. For an initial 0.2 mg/liter free chlorine residual and sewage
level of 0.1% approximate bacterial inactivations of 99.9% and viral mac
tivations of 90% can be expected after 2 hours contact time at pH 8. For
an initial 0.2 mg/liter combined chlorine residual, 90% bacterial and 0%
viral inactivation would be expected for the same conditions of pH, contact
time, and sewage level. With this inactivation information and the assumption
of a level of enteric virus, Salmonella, and Shigella in raw sewage at 1
per ml, (Olivieri et al., 1977), Table 17 was constructed. While the
absolute magnitude of microbial inactivation will depend on the factors
mentioned at the beginning of this discussion, Table 17 does show that the
maintenance of a free chlorine residual will confer considerable protection.
The degree of protection afforded by a combined chlorine residual is small,
and would only be of value in cases where the levels of introduced contami-
nant are extremely low.
MUNICIPAL DISTRIBUTION SYSTEM
The water distribution system is not only the most expensive part of
a public water supply system but is also the most vulnerable. The enormous
pipe surfacetowater volume ratio provides numerous opportunities for
defects and surface for chemical and biological activities. Haney (1961)
expressed the above ratio in terms of 0.6 to 0.7 acres of pipe surface per
1000 populations served, whereas Larson (1966) indicated that each square
foot of pipe surface sees 1 mgd of water.
The Baltimore water distribution sytem is somewhat unique for an Eastern
city. A free chlorine residual can be demonstrated in all parts of town and
the overwhelming majority of samples collected are of good quality. The
water in Frederick water distribution system, on the other hand is treated
by different process. At present, a portion of the water for Frederick is
an untreated upland surface water that is only chlorinated. To maintain a
residual in the transmission line, ammonia is intentionally added. The
92
-------
TABLE 17. ESTIMATED PATHOGEN INTAKE BY WATER CONSUMERS WHEN TAP WATER WITH NO CHLORINE, 0.2 mg/i
FREE CHLORINE. OR 0.2 m /1 COMBINED CHLORINE IS CONTAMINATED WITH 0.1% SEWAGE
Pathogen
intake by
consumer
(2 liters
of water/person_day)*
Enteric
Pathogens
Estimated minimum
infective dose
with no
chlorine
with
free
0.2 mg/i
chlorine
with 0.2 mg/i
combined chlorine
virus
1 (Westwood &
Sattar, 1976)
2
.2
2
Shigella
10 (Bryan, 1974)
2
.002
.2
Salmonella
10,000 (Bryan, 1974)
2
.002
.2
*
National Academy of Sciences (1977)
-------
water in the Frederick system is generally of good quality but does have high
turbidity values and high plate counts at several sampling stations.
Microbiological Quality
Co 1ff orm
986 samples were collected from the municipal water distribution systems
(850 from Baltimore and 186 from Frederick). Less than 1% (6 of 850) of the
samples from Baltimore contained coliform greater than 2 MPNI100 (4 samples
at 2, 1 sample at 6, and 1 sample at 33 MPN/lOO ml). Isolates tested from
each of these samples did not yield the classical -H IMVIC patter for E.
coli or the characteristic -H- INVIC pattern for Enterobacter aerogenes but
rather intermediate patterns of - 1-+ and - 1+1 . About 3% (4 of 136) of the
samples collected in Frederick were positive for coliforms. The coliform
levels were 2, 49, 170 and > 2,400 MPN/lOO ml and were collected at the
same sampling station. The low number of positive coliform samples in both
systems did not permit the expression of any meaningful correlation between
presence and level of coliforms and the chlorine residual. It was moreover,
noted that chlorine residuals were measured in the water In which samples
were positive for coliform.
Bacterial Plate Count-
The bacterial plate count has long been recognized as a useful parameter
in water treatment and has been routinely used to evaluate water treatment
processes. The bacterial plate count has generally been performed on a rela-
tively rich complex medium and incubated aerobically and thus yielded an
estimate of the number of aerobic heterotrophic bacteria. Anaerobic and
autotrophic microorganisms will not grow and, therefore, not be enumerated.
The bacterial plate count will be influenced by the medium employed. A
diluted, weaker medium may yield higher numbers than a richer medium.
Victoreen (1977) reported consistently higher plate counts using an 8fold
diluted Standard Methods plate count medium supplemented with iron. In
laboratory practices too often conditions of incubation also are not con-
sistent and this makes comparisons and evaluations of bacterial plate count
data difficult. Table 18 shows the incubation conditions recommended by
various agencies and laboratories in different parts of the world for the
bacterial plate count test. Temperatures of 20, 22, 28, 35 and 37°C and in-
cubation times of as long as 9 days and as short as 1 day have been employed.
No one plate count method has been universally adopted.
Allen, et al. (1976) and Geidreich et al. (1978) demonstrated that
the presence of high levels of bacteria interferes with the determination
of coliforms with the membrance filter procedure. They have suggested that
the incubation temperature and time be standardized at 35°C and 48 hours.
The rationales for the time and temperature standard have to do with the
possible interference of various bacteria with the coliform determination
such that the standard plate count does not necessarily reflect the number
of microorganisms capable of growth on the medium at optimum condition.
Significant alteration of incubation temperature and time does dramatically
alter the plate count. At 35°C the plate count increased with time till a
plateau was observed at 6 days, while at 20°C the plate count appeared to
reach a plateau at 12 to 14 days. (Figure 20). Whether the time or tempera
94
-------
TABLE 18. RECOMMENDED OR REPORTED INCUBATION TEMPERATURE AND TIME FOR THE
BACTERIAL PLATE COIJNT FOR WATER SAMPLES
Source
Temperature °C
Time, days
European Economic Community
(1975)
37
2
IJSEPA
(1975)
35
2
German Water Regulations
(1975)
20
2
United Kingdom Report #71
37
1
Water Research Center,
United Kingdom 1976
22
22
3
7
Victoreen
(1977)
28
7
Standard Methods
(1971)
35
20
1
2
This Report
20
35
9
4
95
-------
ture of incubation has any particular significance and whether the plateaus
are consistent for other samples and conditions remain to be determined.
In the present state of knowledge the bacterial plate count is believed
to have only limited sanitary significance. No relationship between it and
diseases transmitted by water has been reported. The bacterial plate count,
however, does provide an exceptionally sensitive measure of water treatment
operation and changes in water quality in the distribution system. The
bacterial plate count may be used as a method to check microbial growth in
systems. It may become an increasingly important tool to monitor the con-
dition of activated carbon filters in the treatment of water. Members of
genera containing some species pathogenic to man: Pseudomonas, Flavobacterium
and Aerornonas have regularly been isolated from plates for the Standard
plate count test. (Allen et al., 1976 and Geldreich et al., 1978). These
pathogenic microorganisms are opportunistic in nature and present a health
hazard in unique environments or circumstances.
Relationship Between Chemical, Physical and Microbial Parameters
A linear regression model was utilized to examine the distribution
system data for relationships between the physical, chemical and microbio-
logical parameters measured. Plate count data, although of no demonstrable
sanitary significance, nevertheless give indications of the microbial
quality of distribution system samples. On the other hand, the standard
plate count has been used as an overall indicator of drinking water quality
by Jeffrey and Singley, (1978). Physical and chemical parameters chosen in
this analysis were those that would be expected to have an effect on the
microbiological quality, that is, parameters for which a causal relationship
can be proposed. In the Baltimore distribution system, significant correla-
tion was found between plate counts (20 and 35°C) and free chlorine concen-
tration, turbidity, and temperature.
Free chlorine is an effective bactericide and viricide, and factors in-
fluencing efficiency of disinfection have been well established. (Butter-
field, 1945, 1946; Fair and Geyer, 1954). The correlation between log
plate count (35 and 20°C) and free chlorine residual, and the strong correla-
tion (R = 0.62 and R = 0.73) between mean log plate count and free chlorine
residual found in this study indicate that a free chlorine residual is
effective in controlling the general bacterial population in the Baltimore
system. When many samples from many parts of the distribution system were
assayed, no evidence could be found for the existence of a substantial
population of chlorine resistant microorganisms in spite of recent attention
drawn to apparently chlorine resistant coliform and noncoliform bacteria
found in water distribution system samples. (Herman, 1978; Knowlton, 1977).
Any measurable free chlorine residual was found to reduce the plate count
effectively.
Increased levels of plate count microorganisms were found to be associ-
ated with increased turbidity. This association may be due to a protective
effect, with the colloidal particles shielding microorganisms from the dis-
infectant (Hoff, 1978), or this may be due to microbial action on the pipe
surfaces, resulting in increased turbidity. (Allen, 1977). Thus turbidity
may be a cause or an effect of increased bacterial levels. Data obtained
96
-------
in this study were entirely observational, and do not support or refute
either hypothesis. The turbidity in the Baltimore system was low, generally
less than 1.2 NTU. Even at such low values turbidity was found to be
correlated with the plate count. While individual data points showed
greater scatter, when mean plate count values to turbidity ranges were
considered, R values of 0.73 (35°C plate count) and 0.88 (20°C plate count)
were obtained.
An analysis of this type is complicated by the fact that the chemical
and physical parameters are correlated with each other. Chlorine concentra-
tion showed significant correlation with turbidity and temperature. In
order to account for these interactions, a multiple regression model was
utilized. Since pH was not found to correlate with any of the microbiologi-
cal, physical, or other chemical parameters, this information was omitted
from the multiple regression step. For the 4 day incubation, 35°C plate
count, 22% of the variation in the plate count values (R 2 = 0.22) could be
attributed to the regression on free chlorine residual. The inclusion of
turbidity in the analysis accounted for an additional 6% of the variation
(R 2 = 0.28). When all three variables were included, (free chlorine,
turbidity, and temperature) 32% of the variation (R 2 = 0.32) in plate count
level could be explained. For the 20°C, 9 day incubation plate count, an
R 2 value of 0.41 was obtained when chlorine residual alone was considered.
The inclusion of turbidity and temperature only increased this value to
0.44. These R 2 values are significant at the 99Z level, but are fairly low
since the multiple regression included all the data points as opposed to
individual regressions which were done on mean log plate count values as
well as individual points.
The Frederick system differs from the Baltimore system in that the
surface water supply is treated by the chlorineammonia process and does not
undergo further treatment. The ammonia addition process results in a rela-
tively high total chlorine residual, with only a slight free chlorine
residual. At the levels of combined chlorine observed in the Frederick
systems, false positive measurements of free chlorine with the DPD method
may occur. (Cooper et al., 1974). The mean log 20°C and 35°C plate counts
were found to be more dependent on the free chlorine fraction of the total
residual than on the total residual. Although combined chlorine is a
bactericide, the combined chlorine residual was not as markedly effective
as the free residual in controlling the distribution system bacterial
populations.
As in the Baltimore system, increasing turbidity was found to be
associated with increased mean log plate count. Since the Frederick City
water does not undergo complete treatment, a wider range of turbidities was
encountered. Turbidity was not found to correlate with either free or
total chlorine residual in the Frederick distribution system.
The regression curves for log plate count versus the midpoints of the
ranges of free chlorine residuals for both the Frederick and Baltimore City
distribution system samples are shown in Figure 43. These figures were con-
structed for comparison of the effect of the free residual in the two dif-
ferent systems. The 35°C plate count for the Frederick system samples
97
-------
3.0
z
o
U
Li 1 0
S
4 Frederick
o 1.0 8oI more
z
4 V
U I V
V
0 1 I
0 0.4 0.8 (.2
Free chlorine residual , mg/I
3.0
I .- V
z
0
0 2.0
L U 0
S
40 Frederick
a.-
00
1.0 V
. Bottimore
z V
LU
V . ..-
0 _____________
0 0.4 0.8 1.2
Free chlorine residual, mg/I
Figure 43. Influence of free chlorine residual on mean log plate
counts.
98
-------
showed a greater dependence on chlorine residual, as evidenced by the
larger negative slope, than did the 35°C plate count for the Baltimore
system samples. The 20°C plate count showed almost identical slopes in the
two systems. The Frederick system maintains a high combined chlorine
residual, while the residual in Baltimore is almost entirely of the free
form. A similar figure comparing the effect of turbidity on the mean log
plate count in the two systems is shown in Figure 44. The increase in mean
log plate count with increasing turbidity was similar for the 35°C plate
count, but the 20°C plate count responded differently in the two systems,
with the plate count in the Baltimore system showing a larger dependence on
turbidity. Hoff (1978) stated that . . . the interference of turbidity with
disinfection depends much more on the types of turbidity present than the
number of turbidity units present.
The maintenance of a free chlorine residual, and control of turbidity
are effective methods of reducing the bacterial population in distribution
systems. However, a considerable variability exists which is not accounted
for by the regression analysis. Other factors, such as nutrients and the
inherent variability of biological systems, are also probably important. In
addition, different systems may respond to changes in chemical and physical
parameters in varying degrees, so that control measures sufficient for one
system may not be adequate for another. Generally, the maintenance of a
free chlorine residual, even a low level residual, was found to be the single
most effective control measure.
Microbial Differentiation
A portion of this study was directed to obtain some information on the
groups of microorganisms recovered from the bacterial plate count test and
to evaluate changes in bacterial populations under different conditions
found in the distribution system. Unfortunately the taxonomy of the micro-
bial populations in water recovered on bacterial plates is today unclear
and confused. It has not received the same degree of attention naturally
as the microbial families and genera of medical importance. Methods employed
in this study were not intended to yield firm identification but rather
were intended to group the microorganisms and to evaluate their population
dynamics.
Despite the variability in the groups of organisms between sampling sta-
tion and samples and some minor differences in diversity, the overwhelming
majority of the greater than 6000 isolates collected in this study was Gram
negative nonsaccharolytic rodshaped bacteria. The majority of microorga-
nisms of this category was obligate aerobes but significant numbers of
facultative bacteria were observed. It should be noted that strict anaerobic
bacteria were selectively excluded by the choice of the method for the
plate count. Both the aerobic and facultative groups contained a large
percentage of microorganisms that yielded pigmented colonies. The biochemi-
cal characteristics of the aerobic group are consistent with the members of
the family Pseudornodaceae and the genera Flavobacterium, Alcaligenes and
Moraxella, and those of the facultative groups are consistent with members
of the genera Flavobacterium. These same microorganisms have been reported
in water distribution systems from other parts of the country. (Allen et
99
-------
2.2
I-
2
0
U
Sit U
4 g
-s
go
z
4
l i i
I-
2
0
U
Iit.u
1-0
a.).
4
0
-Jψl
2
4
l i t
Figure 44.
1.8
1.4
I.0
0.6
0.2
0
2.2
1.8
1.4
1.0
0.6
0.2
0
0 0.5 LO 1.5 2.0
Turbidly TU
Influence of turbidity on mean log plate counts.
V
a
.
.
0 0.5 1.0 1.5
Turbidity
V
2.0
NTU
2.5 3.0
.
2.5 30
100
-------
al., 1976; Geidreich et al., 1978). In this study, two distribution systems
50 miles apart, one with water treated by coagulation, sedimentation and
sand filtration and other without and having different chlorine residual
practices yielded similar predominant groups of microorganisms.
Little microbial diversity was observed at majority of the sampling sta-
tions. Several groups made up the major portion of the microorganisms re-
covered, and the same groups of microorganisms were found at each station.
Station 1 (Frederick) and Station 44 (Baltimore) were exceptions, and groups
of microorganisms observed there were more diverse than at other stations.
Eight and 10 additional groups of microorganisms were found over the major
groups. While the 20°C incubation temperature consistently yielded higher
plate counts than the 35°C incubation temperatures, particularly in samples
from the Baltimore distribution system, the bacterial groups recovered from
sample by stations at the different incubation temperatures were also simi-
lar. However, group 10 (possible Aeromanas) and groups 13 and 16 (possible
Enterbacteriaceae, Bacillus and/or Staphylococci) were found almost exclu-
sively at 35°C at station 1, 4, 27, 44 and 48.
Unfortunately, little data on the distribution of microorganisms in
water transmission lines were available for comparison. The same general
groups of microorganisms have been reported in other systems. The similarity
between microorganisms found at the 20°C and 35°C plate counts was surpris-
ing. An explanation for the lack of major shifts of population from station
to station and for different incubation temperatures would be speculation
without further indepth study. Only 6 stations in Baltimore and 2 stations
in Frederick were studied in detail. The predominant bacterial groups were
most probably selected by the restrictive conditions of nutrients and by
their ability to resist the disinfectant residuals, and further by the
methods employed in their recovery and enumeration.
101
-------
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106
-------
0
- .4
APPENDIX A. HOLDING TANK DATA
TABLE A-i. BACTERIAL INACTIVATION, HOLDING TANK STUDIES, pH 8.0, 0.69 to 1.25 lngIl INITIAL FREE
CHLORINE
S
Pun temp Autoclaved
c Sewaqr
C l
Bkpt
mg/I
Chlorine
0 Time
Free Total
Residual.
2 minutes
Free Total
mg/i
120
Free
minutes
Total
Coliform,
2 30
mm. sin.
log
60
mm.
N/N 0
120
mm.
S.
2
sin.
4iphi rurium
30
mm.
log N/N 0
60 120
mm. mm.
. .
2
mm.
ao n i
30
mm.
log N/No
60 120
mm. sin.
20 0 1
150
.69
.90
.02 .69
0
.65
-2.2 <-2.9
<2.9
a 2.9
<2.9
<2.9
<2.9 <2.9
-2.2
<3.1
<3.1 <-3.1
5
.69
.90
0 .54
0
.51
0 .3
.2
.1
0
.3
.3 .4
0
.4
.3 .3
10
.69
.90
0 .35
0
.32
.2 .1
0
.1
.2
.1
.1 .2
.2
.2
.2 .1
10
0
0
0 0
0
0
.3 .2
.2
.1
.2
.1
.1 .2
.2
.2
.1 0
30 10 1
220
1.21
1.39
.05 .95
.01
.91
.5 1.6
2.4
3.2
.6
1.8
<3.4 <3.4
.6
2.7
3.1 <3.3
5
1.21
1.39
.01 .50
0
.46
.1 .2
.1
.8
.2
.2
.2 .6
.1
.2
.2 .4
10
1.21
1.39
0 .24
0
.19
.3 0
.2
.1
.2
0
.1 0
0
.1
0 .1
10
0
0
0 0
0
0
.1 .2
.1
.2
.1
0
.1 .2
0
.1
.2 .1
23 20 1
150
.92
1.13
.03 .78
.02
.71
2.4 <2.9
<2.9
<2.9
2.1
<2.9
<-2.9 <2,9
2.4
<2.8
<2.8 <2.8
5
.92
1.13
.02 .55
.01
.55
.1 .3
.8
2.0
.1
.3
1.0 3.1
.2
.5
1.2 3.5
10
.92
1.13
0 .45
0
.38
0 .2
.4
1.0
0
.1
.4 1.3
0
.3
.4 1.7
10
0
0
0 0
0
0
.3 0
.2
.2
.3
0
-.3 .1
0
.1
.3 -.2
32 30 1
220
1.25
1.45
.03 .83
.03
.76
.5 <3.2
<3.2
<3.2
.8
3.3
<3.3 <3.3
.8
<3.3
.3.3 3.3
5
1.25
1.45
.01 .30
.01
.30
.1 .2
1.5
2.7
.2
.4
.5 <4.0
.1
.4
1.6 <4.0
10
1.25
5.45
0 .08
0
.03
.1 0
.2
0
.1
.1
.2 .1
.2
.1
.1 0
10
0
0
0 0
0
0
.1 .2
.2
0
.2
.1
.3 .1
.1
.2
.2 .1
-------
I-.
0
TABLE A2. VIRAL INACTIVATION, HOLDING TANK STUDIES, pH 8.0, 0.69 to 1.25 mg/i
INITIAL FREE CHLORINE
Run
#
%
Autoclaved
Sewage
f2 ,
2
mm.
log
30
mm.
N/N 0
60
mm.
120
mm.
2
mm.
polio 1,
30
mm.
log N/N 0
60
mm.
120
mm.
20
1
.4
.5
.5
.5
1.0
1.0
1.4
1.7
5
.2
0
0
.2
.1
.3
.7
.7
10
.1
.1
0
0
10
0
-.1
0
0
0
.2
.3
.1
30
1
.3
.5
.4
.3
.8
1.8
<2.7
<2.7
5
.1
.1
.1
.1
.1
.1
.8
1.1
10
. 1
. 1
. 1
. 1
10
.1
0
0
0
.1
.5
.2
.2
23
1
.9
1.0
1.1
1.6
5
.3
.2
0
0
10
. 1
0
. 2
. 1
10
0
.1
0
-.1
32
1
.2
.4
.7
.8
5
0
.1
.1
.4
10
.1
.1
.1
0
10
.1
.1
0
0
-------
TABLE A3. BACTERIAL INACTIVATION, HOLDING TANK STUDIES, pH 8.0, 0.90 to 1.25 mg/i INITIAL.
COMBINED CHLORINE
271) 0
lOin Tmj
C
(1
Autoclavod llkpt
Scwaqe mq/1
ChlorIne R.sidu,-.I, m /l
0 Timo 2 mlriut. . 121) minutes
ree Total Fr.e Total Fro Total
Coil form, log N/N 0
2 30 6)) 120
mm. mm. mm. mm.
S. t pim ri m log N/No
2 30 60 120
mm. mm. mm. mm.
S. oeneL 1o N/Ni,
2 30 61) 120
mm. mm. mm. miii.
0
to
0 .2 .3 .2 .1 .2 .5 1.1
I (1
2(7 0
2 10
0 20
23 20
7 30
9 30
5
10
11
5
10
l0
5
5
10
11
1
5
10
1)
1
5
10
11
5
10
11
1 50
230
230
150
270
270
.99 0
.85 (I
.80
.1
0 .1 -.2
0
.99 (3
.58 0
.49
(1
0 -.2 -.1
0
.99 0
.38 0
.25
.2
.1 .1 .1
0
0 0
0 0
0
0
.1 .1 .1
0
.90 0
.83 0
.80
.2
.2 .5 1.1
0
.90 0
.65 0
.63
.2
0 -.1 -.3
0
.90 0
.51 0
.47
.2
.1 .1 .1
0
0 0
0 0
0
.3
.2 -.2 -.1
0
1.19 0
.87 0
.87
.3
.6 -1.1 2.0
0
1.19 0
.61 0
.46
.1
.3 .7 -1.5
1)
0 0
0 0
0
0
.1 0 -.1
0
1.25 0
1.06 0
1.04
.1
1.7 2.7 <2.7
0
1.25 0
.80 0
.71
.1
.7 1.4 2.4
0
1.25 0
.27 0
.39
0
.3 .9 1.7
0
0 0
0 0
0
0
0 0 0
0
1.13 0
.97 0
.93
-.1
1.0 1.8 <2.9
0
1.13 0
.81 0
.76
.1
.7 1.0 1.7
0
1.13 0
.59 0
.57
.2
.5 .9 1.2
0
0 0
0 0
0
.3
0 .2 -.2
0
1.16 0
1.00 0
.87
.5
<2.5 <2.5
0
1.16 0
.61 0
.48
.4
1.3 <3.2 <3.2
0
1.16 0
.37 0
.25
0
.2 .5
0
0 0
0 0
0
--
-- - --
0
.90 0
.71 0
.66
-.4
- <-2.8 <-2.8
(3
.90 0
.42 0
.30
0
.6 -2.5 -3.5
0
.90 0
.16 0
.10
.1
.1 0 0
0
0 0
0 0
0
0 .1 .3 .2
0 .3 .2 .1
0 0 .1 0
.2 .7 .8 1.3
.2 0 .4 .4
.3 .1 .2 .2
.2 .1 .1 .2
.1 .7 1.2 <2.3
0 .3 .7 1.6
0 .1 .1 .1
0 -.9 2.6 <-2.9
.1 .2 1.0 2.6
.1 .1 .2 1.0
0 .1 0 0
0 1.4 2.3 <2.9
.1 .2 -1.5 2.7
.1 .3 1.1 2.2
.3 0 .3 .1
.5 1.6 <3.1 <3.1
.3 1.0 3.8 <3.8
0 .3 .5 .8
.2 .8 3.3 <3.3
0 .2 .8 <4.0
.2 .1 .2 .1
.2 .2 .9 1.2
0 .2 .2 .4
0 .1 -.1 -.1
.2 .4 .8 1.5
.1 0 -.1 -.6
.1 .2 .1 .2
.2 .2 .1 0
0 .3 1.1 1.9
0 -.2 -.9 -1.5
.2 .2 .1 0
0 1.6 <2.9 <2.9
.2 .7 1.5 -3.6
.2 .1 .9 -2.1
0 0 0 0
.1 1.4 <2.8 <2.8
.1 .6 2.2 <3.5
.3 .4 1.7
0 .1 .3 .2
.5 <2.9 <2.9 <2.9
.3 -1.6 3.0 -3.6
.1 .1 .3
-.3 - -2.R -2.R
.1 .5 <3.5
0 0 0 -.1
-------
I-a
0
TABLE A-4. VIRAL INACTIVATION, HOLDING TANK STUDIES, pH 8.0
0.90 to 1.25 mg/i INITIAL COMBINED CHLORINE
Nun
t
Autoclaved
SSwa 9 .
2
m n.
f2 log N/N 0
30 60
m n. fliln.
120
mm.
2
mm.
oflo 1
30
mmn.
log f l/N 0
61)
mm.
120
mm.
11
1
S
10
11
0
.2
0
.1
0
0
0
.1
0
.1
0
.1
-.1
.1
0
.1
20
1
5
10
I I)
0
0
0
0
.1
.1
0
.1
.1
0
-.1
0
.1
.1
-.1
0
.3
.1
0
.9
.2
.2
.7
1.0
.3
.8
.8
.1
2
1
5
.2
0
.7
.1
0
.4
.1
.1
.6
.2
0
.1
6
1
5
10
11
.1
.1
.1
0
.3
.2
.2
0
.3
.2
0
.5
.4
.3
0
0
-.2
1.2
0
1.6
.1
1.6
0
23
1
5
10
10
.1
.2
.1
0
.1
.1
0
.1
.1
.2
.1
0
.1
.1
.1
.1
7
1
5
10
11
0
.2
0
0
0
.1
.1
.1
.4
0
.1
.1
.7
.3
.3
0
.3
.3
0
1.7
1.5
.1
1.7
1.9
0
2.2
1.8
.1
9
1
5
10
11
0
0
.1
0
.2
.1
0
0
.4
.1
0
.1
.4
.2
0
0
0
.3
0
-.1.9
1.2
0
2.0
1.7
.1
1.9
1.9
0
-------
TABLE A 5. BACTERIAL INACTIVATION, HOLDING TANK STUDIES, pH 8.0, 0.21 to 0.26 mg/i INITIAL FREE
CHLORINE
.10
20
50
10
.10
20
50
.10
.10
.20
.50
10
.50
1.00
10
.23 .35 .03 .23 .01
.23 .35 .02 .22 0
.23 .35 .01 .21 0
0 0 0 0 0
.21 .34 .05 .24 .03
.21 34 .03 .24 .02
.21 .34 .02 .22 .01
0 0 0 0 0
.26 .37 .05 .23 .01
.26 .37 .05 .22 .01
.26 .37 .02 .18 .01
.25 .37 .03 .22 .02
.25 .37 .02 .23 .01
.25 .37 0 .22 0
0 0 0 0 0
.1 .8 1.1 1.5
.1 .1 .4 .5
.1 .2 .2 .2
-.1 0 .1 0
1.3 <3.4 <3.4 <3.4
.5 <3.7 <3.7 <3.7
.2 .1 .3 .6
.1 .1 .1 0
.4 1.8 2.5 <3.7
.3 .3 .3 .8
.1 .1 .1 0
3.3 <3.7 <3.7 <3.7
.3 .7 .9 2.2
.2 .2 .2 .2
.2 .1 .2 .1
.8 2.2 2.3 2.8
.2 1.0 1.6 1.6
.4 1.1 1.2 1.6
0 0 .1 .1
1.6 <3.5 <3.5 <3.5
.9 <3.8 <3.8 <3.8
.4 .8 1.0 1.3
.2 0 0 .3
.5 1.4 1.5 2.2
.4 .5 .6 1.0
0 .2 .1 .4
2.3 3.6 <-3.6 <3.6
.3 .9 1.4 2.3
.2 .1 .3 .7
.2 0 .3 .1
0 2.2 <3.2 3. 2
.1 .7 1.3 2.5
0 .4 .9 1.9
0 .1 .1 0
.9 <3.2 <3.2 <3.2
.4 <3.5 <3.5 <3.5
.4 .5 .9 1.3
.2 .2 .1 0
1.4 1.8 (3.5 <35
.3 .4 .5 1.2
.1 0 .1 .2
3.5 <3.6 <3.6 <3.6
.5 .8 1.4
.3 .3 .4 .6
.1 .1 .4 .1
I -
I-I
%
Chlorine
Renidual,
mg/i
Coliform,
log
N/N 0
S. typhimurium, log
N/N 0
S. sonnoi,
log
N/N 0
Temp Autoclaved
Rkpt
0 Time
2 minute, 120 minute,
2
30
60
120
2
30
E.0
120
2
30
60
12(1
C Sewage
mg/i
Free Total Free
Total
Free
Total
mm.
mm.
mm.
mm.
mm.
mm.
mm.
mm.
mm.
mm.
mm.
mm.
2( 0
28 0
31 10
25 20
15(1
150
220
150
.21
.20
.21
0
- 23
.23
.21
0
.21
20
.17
.20
.19
.18
0
-------
p,)
TABLE A6. VIRAL INACTIVATION, HOLDING TANK STUDIES, pH 8.0, 0.21
to 0.26 mg/I INITIAL FREE CHLORINE
Run
#
%
Autoclaved
Sewage
f
2
mm.
2, log
30
mm.
N/N 0
60
mm.
120
mm.
2
mm.
polio 1,
30
mm.
log N/N 0
60
mm.
120
mm.
26
.10
.4
.8
.8
-.8
.5
1.6
1.9
1.8
.20
.3
.3
.3
.3
.3
1.5
1.3
1.5
.50
.3
.4
.3
.4
.10
0
0
0
0
.1
0
.1
.1
28
.10
.3
2.0
<2.4
<2.4
.20
.2
.7
.9
1.0
.50
.2
0
.2
.2
.10
0
0
.1
.1
31
.10
.4
.6
.5
.6
.5
1.3
1.8
1.6
.20
.2
.4
.4
.4
.4
1.3
1.4
1.4
.50
.6
.5
.5
.6
25
.10
.6
<2.6
<2.6
<2.6
.50
-.1
.2
.2
.2
1.00
.1
0
0
.1
.10
0
0
0
0
-------
TABLE A7. BACTERIAL INACTIVATION, HOLDING TANK STUDIES, pH 8.0, 0.23 to 0.37 mg/i
INITIAL COMBINED .CHLORINE
Run
Ii
Temp
C
%
Autoclaved
Scw go
Bkpt
mq/1
Chlorine Residual. mg/i
0 Time 2 minutes 120 minutes
Free Total Free Total Free Total
Coliform, log N/N 0
2 30 60 120
mm. mm. mm. mm.
S. phihuui 4n, log N/N 0
2 30 60 120
mm. mm. mm. mm.
S. eoP nei, log N/N 0
2 30 60 120
mm. mm. mm. mm.
H
H
(J3
ISO
150
230
150
270
28 0
5 20
25 20
8 30
.01
05
.10
.10
.01
05
.10
.10
.01
.05
.10
.125
.01
05
.10
.10
.01
.05
.10
125
0
s 0
.33 0
.31
0
.35 0
.30 0
.30
0
.35 0
.30 0
.30
0
0 0
0 0
0
0
.34 0
.30 0
.29
0
.34 0
.30 0
.29
0
.34 0
.30 0
.29
0
0 0
0 0
0
0
.23 0
.22 0
.20
0
.23 0
.21 0
.20
0
.23 0
.20 0
.20
0
0 0
0 0
0
0
.37 0
.34 0
.32
0
.37 0
.33 0
.31
0
.37 0
.33 0
.31
0
0 0
0 0
0
0
.27 0
.25 0
.23
0
.27 0
.23 0
.21
0
.27 0
.24 0
.20
0
0 0
0 0
0
.1
.1
0
.1
0
.1
.1
.1
.1
.1
.4
0
.5
.2
.2
.2
.2
.1
.1
0
.1 -.1 .2
.1 .2 .2
.3 .1 .2
0 .1 0
0 0 .1
0 -.1 -.1
.1 .1 .1
.1 .1 0
0 .2 1.1
.1 .2 1.0
0 -.2 1.1
0 0 0
.6 .8 -1.8
.5 .6 1.9
-.2 .9 1.8
.1 .2 .1
.1 .9 1.7
0 .6 1.3
.2 .7 1.7
.1 .l .1
.1 0 .1 .5
.1 .2 .3 .4
.1 .4 .1 .2
0 0 .1 .1
.1 .1 .1 .1
0 .1 0 -.1
.2 .1 .1 .1
-.2 0 0 .3
0 0 .1 -.9
0 .1 .3 .7
.1 0 - .8
.1 .1 .1 .1
.4 .5 1.1 2.7
.2 .4 1.0 2.0
.2 .2 1.3 2.6
.2 0 .3 .1
.3 .1 .2 2.3
.1 .1 .1 1.0
0 0 -.2 -2.2
0 0 .1 .1
.2
.2
.1
0
.2
.1
.2
.2
0
0
0
.1
.4
.1
0
.1
0
.2
.1
.1
.1 .2 .5
.3 .2 .4
.5 .5 -1.0
.1 .1 0
.2 .2 .1
.2 0 .3
.1 .2 .2
.2 .1 0
0 -.1 -1.0
0 .2 .9
.1 -.9
0 .1 -.2
.7 1.1 3.1
.6 .7 2.6
.5 1.2 2.5
.1 .4 .1
.2 .7 2.0
.1 .8 -2.0
.2 -.9 2.0
0 -.1 0
-------
TABLE A-8. VIRAL INACTIVATION, HOLDING TANK STUDIES, pH 8.0,
0.23 to 0.37 mg/i INITIAL COMBINED CHLORINE
Run
%
Autoclaved
S waqe
f2,
2
mm.
log
30
mm.
N/N 0
60
mm.
120
mm.
p01
2
mm.
10 1,
30
mm.
log N/N 0
60
mm.
120
mm.
26
.01
0
0
.2
.1
.5
.5
1.0
1.0
.05
.1
.1
.1
.1
.3
.4
.7
.9
.10
0
0
-.1
0
.10
0
0
0
0
.1
0
.1
.1
20
.01
.1
.2
.2
.1
.05
.2
0
0
.1
.10
.1
0
.1
.1
.10
0
0
.1
.1
5
.01
0
.1
.2
.4
.05
.1
.1
.3
.3
.10
0
.1
.2
.4
.125
.1
0
.1
.1
25
.01
0
.1
.2
.4
.05
0
.1
.1
.2
.10
0
0
.1
.1
.10
0
0
0
0
8
.01
.1
0
.1
.2
.05
.1
0
.2
.3
.10
0
0
.2
.3
.125
.1
.1
0
.1
I .-
-------
TABLE A9. BACTERIAL INACTIVATION, HOLDING TANK STUDT S, pH 6.0, 0.75 to 1.26 mg/i
INITIAL FREE CHLORINE
Pun Tfmp
C
Autoclavod
Sewage
llkpt
eq/i
Chlorine R .jcidual. mg/i
0 Tine 2 minutes 120 minutes
Free Total Free Total Free Total
Coliforem, log N/N 0
2 30 60 120
mm. mm. mm. mm.
tijplmimurium , log N/NQ
2 30 0 1 0
mm. mm. nun, nun,
7. Sonn <i, log N/N 0
30 60 120
nun. mm. nun, nun.
II
U!
19 0
14 10
30 10
22 20
12 30
150
270
220
150
220
5
10
10
5
S
5
1 ( 3
10
5
10
5
10
16
.75
.91 .06
.64 .02
.60
.75
.91. .02
.47 0
.41
.75
.91 0
.30 0
.23
0
0 0
0 0
0
.91
1.07
.75 0
.71
.91
1.07 0
.51 0
.38
0
0 0
0 0
0
1.26
1.45 .09
1.01 .05
.93
1.26
1.45 .03
.59 .01
.4)
1.26
1.45 .01
.24 0
.14
0
0 0
0 0
0
.92
1.15 .06
.83 .02
.74
.92
1.15 0
.58 0
.46
.92
1.15 0
.34 0
.23
0
0 0
0 0
0
1.26
1,45 .03
.91 .03
.86
1.26
1.45 0
.35
.29
1.26
1.45 0
.08 0
.04
0
0 0
0 0
0
<3.1
<3.1
<3.1
<3,1
2.8
<3.8
<3.8
<3.8
.3
.6
.7
1.2
.2
.1
.2
.1
<2.6
<2,6
<2,6
<2.6
3.1
<3.3
<3.3
<3.3
0
.1
.1
0
<3.3
<3.3
<3.3
<3.3
3.7
<-4.0
<4.0
<4.0
.4
.6
.6
.7
.2
0
.1
.1
<3.0
<3.0
<3.0
<3.0
2.7
3.7
<3,7
<3.7
.4
.9
2.6
<4.0
.2
.2
.2
.1
3.2
<3.2
<3.2
<3.2
.6
3.6
<3.9
<3.9
-.4
.4
.4
.3
0
.1
0
.1
<3.2
<3.2
<3.2
<3.2
2.8
3,7
<3.8
<3.8
-.5
.8
.8
1.2
.2
0
.4
.1
<3.0
<3.0
<3.0
<3.0
3.4
3.4
<3.7
<3,7
-.1
0
.1
0
<3.3
<3.3
<3.3
<3.3
2.5
3.3
4.0
<4.0
.3
.6
.4
.5
.1
.1
.1
0
<3.2
<3.2
<3.2
<3.2
2.6
<3.8
<3.8
<3.8
.4
.7
1,2
3.6
.2
.3
.3
.1
<3.3
<3.3
<3.3
<3,3
.6
3.0
<4,0
<4.0
.5
.1
.4
0
.3
0
.3
0
<3.1
<3.1
<3.1
<3.1
3,4
<3.8
<3.8
<3.8
.4
.7
.9
1.3
.1
0
.3
.2
<2,8
<2,8
<2.8
<2.8
3.2
<3.5
<3.5
<3.5
-.2
0
.1
0
<3.4
<3.4
<3.4
<3.4
3.8
<4.1
<4.1
<4.1
.4
.6
.7
.9
.1
.1
0
.1
<3.1
<3.1
<3.1
<3.1
3,0
<3.8
<3.8
<3.8
.4
.9
<4.1
.1
.1
.1
.1
<3.4
<3.4
<3.4
<3.4
.8
<4.1
<4.1
<4.1
.5
.3
.5
.1
.4
.2
-.3
.1
-------
0
TABLE A1O. VIRAL INACTIVATION, HOLDING TANK STUDIES,
pH 6.0, 0.75 to 1.26 mg/i INITIAL FREE CHLORINE
Run
I
%
Autoclaved
Sewage
f2,
2
mm.
log N/N 0
30 60
mm. mm.
120
mm.
2
mm.
polio 1,
30
mm.
log N/N 0
60 120
mm. mm.
19
1
1.0
1.6
1.6
2.1
1.7
2.7
3.5 <3.8
5
.6
.6
.7
.7
.8
.7
.7 .8
10
.3
. 3
.2
. 3
10
.1
0
.1
0
.1
.1
.1 0
14
1
1.5
2.1
2.1
2.1
1.5
3.2
3.5 3.5
5
1.0
.9
-.9
.9
5
0
.1
.1
.1
.3
0
0 .2
30
1
2.6
<2.6
<2.6
<2.6
2.3
<2.7
<2.7
5
.8
.8
.9
.9
.6
1.7
1.8 <-2.7
10
.3
.3
.3
.5
10
0
.1
.1
0
0
.5
.2 .1
22
1
2.0
<2.9
<2.9
<2.9
5
.8
1.2
.8
.9
10
. 3
.5
.3
.3
0
0
0
0
32
1
1.7
2.6
5
.4
.7
.9
1.1
10
.1
.3
.4
.3
10
0
.1
-.1
0
-------
TABLE A-il. BACTERIAL INACTIVATION, HOLDING TANK STUDIES, pH 6.0, 0.88 to 1.25 mg/i INITIAL
COMBINED CHLORINE
270 0 .99
Run Temp
C
%
Autoclav.d
Sewaqo
Rkpt
mg/I
Chlorine Residual, mg/i
0 Time 2 minutes 120 minutes
Iree Total Free Total Free Total
Coliform , log N/NQ
2 30 60 120
mm. mm. mm. mm.
3. t phimiw . um, log N/N 0
2 30 60 120
mm. mm. isin. mm.
S. ao,rn X , log N/U 0
2 30 60 120
mm. mm. mm. mm.
I - .
-4
11 0
19 1
2 10
14 10
6 20
22 20
7 30
9 30
1
S
10
11
1
5
10
11
1
5
11
1
5
5
5
10
11
S
10
10
5
10
11
5
10
11
150
2)0
270
230
150
270
270
0
.87 0
.86
.1 .6 -1.1 -2.7
3
. .99 0
.58 0
.48
.2 .1 .6 -1.1
0
.99 0
.30 0
.18
.2 .1 .2 .2
0
0 0
0 0
0
.1 0 -.1 -.1
0
.88 0
.82 0
.79
.1 1.8 2.8 <-3.1
0
.88 0
.70 0
.6)
.1 .6 -2.0 <3.8
0
.88 0
.53 0
.47
.2 .6 1.2 -3.1
0
0 0
0 0
0
.2 .1 .2 .1
0
1.19 0
1.06 0
.93
.1 <2.3 <2.3 <2.3
0
1.19 0
.75 0
.55
.1 2.1 <3.0 <3.0
0
0 0
0 0
0
.1 0 .1 0
0
1.07 0
.94 0
.90
.1 1.6 <2.6 <2.6
0
1.07 0
.6]. 0
.54
.1 1.0 2.6 <3.3
0
0 0
0 0
0
0 .1 -.1 0
0
1.25 0
1.02 0
.58
0 2.2 <2.7 <2.7
0
1.25 0
.80 0
.48
.1 2.1 <3.4 <3.4
0
1.25 0
.49 0
.32
0 1.7 2.7
0
0 0
0 0
0
0 0 0 0
0
1.15 0
1.01 0
1.00
.2 <3.0 <3.0 <3.0
0
1.15 0
.86 0
.76
0 <3.7 <3.7 <3.7
0
1.15 0
.66 0
.50
.1 3.4 <4.0 <-4.0
0
0 0
0 0
0
.2 .2 .2 .1
0
1.16 0
1.05 0
.88
.4 <2.5 <2.5 <2.5
0
1.16 0
.66 0
.52
.4 2.2 <3.2 <3.2
0
1.16 0
.17 0
.12
.2 .2 .4
0
0 0
0 0
0
-.1 0 .1 .1
0
.90 0
0
.78
0 <2.8 <2.8 <2.8
0
.90 0
.42 0
.27
0 .5 <3.5 <3.5
0
.90 0
.12 0
.05
.2 .1 0 0
0
0 0
0 0
0
-.1 0 0 .1
.1 .1 -.8 2.6
.1 0 -.4 -.8
.1 .1 .2 .2
.2 0 .1 .1
.2 1.4 2.6 <3.2
0 - .8 1.6 <3.8
.3 .9 1.3 3.0
.2 0 .4 .1
0 <2.5 <2.5 <2.5
.1 2.0 <3.2 <3.2
0 0 0 0
0 2.1 <3.0 <3.0
.2 .9 2.6 <3.7
.1 0 .1 0
0 2.4 <2.9 <2.9
0 1.5 <3.6 3.6
.1 .7 2.2
O .1 0 .2
.1 <3.2 <3.2 <3.2
0 3.5 <3.8 <3.8
0 2.4 4.0 <4.1
.2 .3 .3 .1
0.1 <3.1 <3.1 <3.1
.1 1.0 3.5 <3.8
.1 .1 .4 .9
.2 0 .1 0
0 <3.3 <3.3 <3.3
.1 .2 1.2 <4.0
0 .1 .1 .2
0 0 0 .1
.2 .8 <-2.4 2.4
.2 .7 .7
.1 -.3 -.6 -.6
.3 0 .2 .1
0 2.3 <3.1 <3.1
0 1.0 2.9 <3.8
.2 .7 1.7 <4.1
.1 0 .3 .2
0 <2.9 <2.9 <2.9
.1 2.2 <3.5 <3.5
0 .1 .1 0
0 <2.8 <2.8 <2.8
0 <3.5 <3.5
.2 0 .1 0
.1 <3.0 <3.0 <3.0
0 <3.7 <3.7 <3.7
.1 1.5 2.7
0 0 0 .2
0 <3.1 <3.1 <3.1
0 3.4 <3.8 <3.8
.1 3.5 <4.1 <4.1
.1 .1 .1 .1
.4 <2.9 <2.9 <2.9
.1 <3.6 <3.6
.1 .2 1.5 -
.2 0 .1 .1
0 <2.8 <2.8 <2.8
.1 1.9 <3.5 <3.5
.2 .1 .1 0
.1 .1 0 .1
-------
H
H
TABLE A12. VIRAL INACTIVATION, HOLDING TANK STUDIES,
pH 6.0, 0.88 to 1.25 mg/i INITIAL COMBINED CHLORINE
Run
0
%
Autoclav .d
Sow qo
2,
2
mm.
log N/N 0
30
nUn.
60
nUn.
120
nUn.
pol
2
nun.
io 1,
30
mm.
log U/rl ,
(,0 120
nUn. mm.
11
1
10
11
.3
.1
0
0
.2
.1
.1
-.1
.2
.1
0
.1
.4
.2
-.1
.1
19
1
5
10
0
0
.1
.1
.1
0
0
0
.1
0
0
.1
.1
.2
.1
0
1.0
.2
.1
.9
.1
.1
1.6 1.5
1.1 1.2
.1 0
2
1
5
11
.1
-.1
.8
.1
.1
.3
.2
.1
.7
.2
.2
.2
14
1
S
5
.2
.2
0
.3
.3
.1
.3
.3
.1
.3
.3
.1
.4
.3
1.2
0
1.2 1.8
0 .2
6
1
5
10
11
.2
.1
.1
0
.3
.2
.2
.1
.5
.4
.2
0
-.9
.6
.5
0
.9
.1
2.1
0
<2.6 <2.6
0 .1
22
1
5
10
10
.4
.5
.6
0
.7
.2
.2
0
.4
.3
.2
0
.5
.5
.4
0
7
1
5
10
11
.2
.1
.2
.1
.4
.3
.3
.1
.8
.6
.3
0
1.2
1.0
.4
.1
.6
.8
.1
2.1
1.8
.1
2.6 2.7
1.4 1.8
0 .2
9
1
5
10
11
0
.1
0
0
.1
.1
.1
0
.4
.2
-.1
0
.7
.2
-.1
0
.3
.1
.1
1.7
1.2
.1
3.1 2.9
1.9 1.6
.1 0
-------
TABLE A -13. BACTERIAL INACTIVATION, HOLDING TANK STUDIES, pH 6.0, 0.18 to 0.28 mg/i INITIAL
FREE CHLORINE
Run
*
Temp
°C
S
flutoclaved
Sewar;e
Ukpt
ml/l
Chlorine Residual, m o/i
0 Time 2 minutes 120 minutes
Free Total Free Total Free Total
Coliform, log N/N 0
2 30 1,0 120
mm. rein. mm. rein.
S. typhi rr1 , log N/N 0
2 30 60 120
rein, rein, rein, rein,
S. 8onne , log N/N 0
2 30 60 120
nrin. rein. mm. rein.
27 0 .10 150 .28 .38 .11 .30 .05 .29 <-3.3 <-3.3 -3.3 <-3.3 -3.5 <3.5 -3.5 <3.5 <3.0 <-3.0 -3.0 <-3.0
.20 .29 .38 .09 .30 .04 .27 <3.6 <3.6 <-3.6 <3.6 <3.4 3.8 <3.8 <3.8 <3.3 <3.3 <3.3 <3.3
.50 .28 .38 .09 .29 .01 .27 <4.0 4.0 <4.0 4.0 4.0 <4.2 <4.2 <4.2 <3.7 <3.7 <3.7 3.7
.10 0 0 0 0 0 0 .1 .1 0.1 .2 .1 .1 0 .2 .1 -.1 0 .2
29 10 .10 220 .24 .34 .06 .25 .03 .21 3.0 <3.2 <3.2 <3.2 3.0 <3.5 <3.5 <3.5 <3.2 <3.2 3.2 <3.2
I- .
.20 .24 .34 .05 .23 .02 .22 3.2 <-3.5 <-3.5 <-3.5 2.9 -3.3 -3.8 <3.8 3.2 <3.5 --3.5 <-3.5
.50 .24 .34 .03 .19 .01 .18 3.1 3.5 3.3 3.9 2.8 3.1 3.3 4.2 3.9 <3.9 <3.9 <3.9
.10 0 0 0 0 0 0 .1 .3 .2 .1 .1 0 .1 .1 .1 .2 .2 .3
31 10 .10 220 .28 .42 .08 .27 .04 .23 <3.7 <3.7 <3.7 <3.7 3.6 <3.6 <3.6 <3.6 3.5 <3,5 <3.5 <3.5
20 .28 .42 .05 .25 .02 .24 3.2 <4.0 <4.0 <4.0 2.9 3,8 3.8 4.0 3.8 3.8 3.8 3.8
.50 .28 .42 .03 .21 .01 .21 4.4 <4.4 <4.4 4.4 3.6 3.9 4.2 <4.3 -4.2 <4.2 <4.2 <4.2
.10 0 0 0 0 0 0 0 0 0 0 0 0 0 .1 0 0 -.1 (3
24 20 .10 150 .18 .30 .03 .22 .03 .17 3.1 (3.2 <3.2 3.2 2.5 <3.4 <3.4 <3.4 <3.0 <3.0 <3.0 <3.0
.50 .18 .30 .01 .20 .01 .16 2.8 3.6 <3.9 <3.9 2.2 2.8 3.3 3.8 2.8 3.5 <3.7 <3.7
1.00 .18 .30 .01 .17 .01 .15 .8 2.8 3.4 4.2 1.1 2.1 2.5 3.1 .7 2.8 <4.0 <4.0
.10 0 0 0 0 0 0 .1 .2 -.1 .1 0 -.1 0 .1 0 0 .1 .1
-------
F.,)
0
TABLE A14. VIRAL INACTIVATION, HOLDING TANK STUDIES, pH 6.0, 0.18 to
0.28 mg/i INITIAL FREE CHLORINE
Run
N
%
Autoc].aved
Sewage
f2,
2
mm.
log N/N 0
30 60
mm. mm.
120
mm.
2
mm.
polio 1,
30
mm.
log N/N 0
60
mm.
120
mm.
27
.10
.9
<2.8
<2.8
2.8
.4
2.7
<2.7
<2.7
.20
.9
2.7
<3.0
<3.0
.4
2.3
<2.7
<2.7
.50
.9
2.1
2.2
2.3
.10
0
0
0
0
.1
.1
0
0
29
.10
.8
1.7
1.7
1.8
.3
<1.8
<1.8
<1.8
.20
.9
1.3
1.4
1.4
.3
1.8
<1.8
.50
.8
-.7
.9
-.7
.10
0
0
0
0
.1
0
.1
0
31
.10
1.0
1.8
2.8
<2.8
.9
3.0
<3.0
<3.0
.20
.9
1.6
1.6
1.6
.8
2.2
1.9
2.3
.50
.8
.9
.9
.9
.10
.1
.1
0
0
.2
.2
.4
.4
24
.10
.7
1.3
1.7
1.8
.50
.6
-.8
.8
-.8
1.00
.6
.6
.8
.8
.10
.1
0
.2
0
-------
TABLE A15. BACTERIAL INACTIVATION, HOLDING TANK STUDIES, pH 6.0, 0.23 to 0. 38 mg/i INITIAL
COMBINED CHLORINE
.01
05
10
10
.01
05
.10
.10
21) .01 230
(15
10
125
.01
.05
10
.10
.01
.05
10
.125
0 .2 .9 -3.1
.3 .4 .6 2.0
0 0 .8 2.3
-.1 .1 -.1 .2
0 .5 2.4 <3.3
.1 .2 -1.2 3.8
.1 .3 1.6 <4.1
.1 .3 .2 .1
.1 0 .7 <2.1
0 0 .6 <2.8
0 .1 .4 3.1
.1 .1 .1 0
.2 1.0 <3.3 <3.3
.1 .8 3.4 <4.0
.1 1.0 3.8 <4.3
.1 .2 .1 .1
0 1.0 <2.3 <2.3
.2 1.3 <3.0 <3.0
0 1.1 2.7 <3.3
0 0 -.1 0
.1 .2 .8 2.4
.3 .6 2.7
.1 .2 .5 2.1
.1 .1 0 .2
.2 .7 <3.1 <3.1
.1 .5
.1 .5 <4.1
.1 0 .1. .1
0 .1 .6 <2.3
.2 0 .7 <3.0
0 .1 .2 2.1
.1 .1 .1 .1
.5 .7 3.2 <3.5
.3 .8 2.5 <4.2
.3 .6 3.1 <4.5
0 .1 0 .1
.1 .1 2.6 <2.6
.2 0 2.9 <3.3
.1 .1 2.3 <3.6
0 0 0 0
0 0 -.9 <3.1
.2 -.4 .6 -3.6
.1 .5 0 .
.1 .6 <3.0 <3.0
o i.n <3.7
0 -2.0 -- <4.0
.1 .2 .2 .3
.2 0 1.6 (2.2
.2 .1 1.5 <2.9
0 .1 1.2 <3.2
.1 0 .3 0
.2 1.9 3.3 <3.3
.1 - <4.0 <-4.0
.2 <4.3 <4.3
0 0 -.1 .1
0 1.9 <2.2 <2.2
0 1.9 <2.9 <2.9
.1 1.8 <3.2 <3.2
.1 0 .1 0
(1
1(1
I 5U
22(1
80n
0
Temp
C
Autoclaved
Sr w.iq<
Bkpt
mg/I
Chlorine Fe
-------
TABLE A16. VIRAL INACTIVATION, HOLDING TANK STUDIES, pH 6.0,
0.23 to 0.38 mg/i INITIAL COMBINED CHLORINE
Run
N
t
Autoclaved
SeWage
fZ
2
man.
. log
30
mm.
N/N 0
60
mm.
120
mm.
p01
2
mm.
iC) 1,
30
mm.
lOg N/N 0
60 120
mm. mm.
27
.01
.2
.3
.1
.2
.1
.1
.4 .9
.05
.1
.3
.2
.3
0
.2
.4 .6
.10
.3
.1
.2
.1
.10
0
0
0
0
-.1
.1
0 0
29
.01
0
0
.2
.1
.9
.3
.7 1.1
.05
0
.1
.3
.2
.1
.2
.7 <1.8
.10
.1
.1
.1
.3
.10
0
0
0
0
.1
0
.1 0
5
.01
0
.1
.3
.4
.05
0
.1
.3
.4
.10
.1
0
.4
.3
.125
0
.1
.1
0
24
.01
0
.1
.3
.4
.05
.1
.1
.3
-.4
.10
0
.3
.3
.4
.10
.1
0
.2
0
8
.01
0
.1
.1
.6
.05
.2
.1
.2
.5
.10
0
.1
.2
.6
.125
.1
.1
0
0
-------
APPENDIX B. EXTENDED TIME DATA
TABLE Bi. BACTERIAL DATA, EXTENDED TIME STUDIES, DECHLORINATED CONTROLS
1 coliform, bacteria/mi
Run Temperature Autoclaved Time
Number p11 Sewage 0 2 hr. 24 hr. 4 day 5 day 6 day 7 doy
26 0 8 .10 1.6 ES 1.6 ES ND 6.8 E4 ND 4.7 E4 ND
28 0 8 .10 1.6 E5 1.6 ES ND 9.4 E4 ND NI) 4.0 E4
25 20 8 .10 1.1 ES 1.1 ES 7.4 E4 ND ND 3.0 E4 ND
S 20 8 .13 1.8 114 1.8 E4 1.6 E4 ND ND ND ND
27 0 6 .10 2.3E5 2.3E5 1.2E5 ND ND i.1E5 NI)
24 20 6 .10 1.6 E5 1.6 ES 1.2 ES ND ND ND ND
5 20 6 .13 1.5 E4 1.5 E4 1.5 114 ND ND ND ND
20 0 8 10 7.4 E4 7.4 E4 ND ND 5.0 E3 ND ND
23 20 8 10 7.4 E4 7.4 E4 1.2 E6 ND 2.7 E5 ND 4.0 E5
32 30 8 10 1.4 E5 1.4 ES 1.4 115 2.0 ES ND 1.6 ES ND
19 0 6 10 1.2 E5 1.2 ES 7.3 114 ND ND ND 6.4 114
22 20 6 10 9.5 E4 9.5 E4 1.3 E6 ND ND ND 1.4 E5
32 30 6 10 1.6 E5 1.6 E5 2.1 ES 9.0 114 ND 5.5 E4 ND
9 30 6 11 7.0 E4 7.0 114 4.1 E5 6.7 ES ND NI) ND
-------
TABLE B-2. BACTERIAL DATA, EXTENDED TIME STUDIES, DECHLORINATED CONTROLS
2 hr. 26 hr.
5
I.-
p )
8. 4phims mum, bacteria/mt s. onnii, bacteria/rn)
Run TIrn( Tttfl ?
day 6 day
NI) 4.4 E4
NI) ND
7 day
ND
1.0 ES
_________ 0
1.6
1.0
ND 1.4
ND 2.1
NI) 1.3
5
2 hr.
ES 1.6 E5
E5 1.0 E5
E5 1.4 ES
E4 2.1 E4
E5 1.3 ES
24 hr.
ND
NI)
8.3 E4
1.2 E4
1. 2 E5
4 day
4.4 E4
7.2 E4
ND
ND
ND
ND
NI)
Number
0
4 day
26
1.6 ES
1.6 ES
NI)
5.2 E4
28
1.3 E5
1.3 E5
ND
9.3 E4
25
1.4 E5
1.6 ES
4.7 E4
ND
ND
5.2 E4
5
3.5 E4
3.5 E4
1.6 E4
ND
ND
ND
21
2.4 ES
2.4 E5
1.1 E5
NI)
ND
9.5 E4
24
1.6 ES
1.6 ES
1.3 ES
ND
ND
ND
ND
1.3 E5
1.3 ES
8.5 E4
5
2.4 E4
2.4 E4
3.2 E4
NI)
NI)
ND
NI)
1.9 E4
1.9 E4
1.6 E4
20
8.0 E4
8.0 E4
5.0 E3
NI)
NI)
ND
NI)
1.3 ES
1.3 ES
NI)
ND
4.1
E4
NI)
NI)
23
7.8 E4
7.8 E4
1.6 ES
NI)
5.0
F.4
NI)
3.0 E4
7.0 E4
7.0 F6
2.5 E4
ND
3.0
I 4
NI)
8.5 E6
32
2.1 ES
2.1 ES
2.5 E5
3.1 E5
ND
2.8 ES
ND
1.9 E5
1.9 E5
2.9 E5
2.7 ES
ND
2.2 ES
NI)
19
1.4 ES
1.4 ES
8.3 E4
ND
NI)
ND
7.4 E4
1.3 ES
1.3 1!5
8.1 E4
NI)
NI)
ND
7.1 E4
22
1.4 E5
1.4 E5
8.8 ES
ND
ND
NI)
7.0 E4
1.2 E5
1.2 E5
5.2 E5
NI)
NI)
ND
7.0 ES
32
2.1 ES
2.1 ES
1.7 ES
2.7 E5
ND
1.5 ES
ND
2.7 ES
2.7 E5
6.5 ES
6.0 ES
ND
1.2 ES
NI)
9
2.3 E5
2.3 E5
2.9 ES
2.9 E5
ND
ND
ND
6.3 E4
6.3 E4
7.0 E4
2.6 E5
ND
ND
ND
ND
ND
ND
ND
ND
N T)
ND
6 day
5.2 E4
ND
3.7 E4
ND
8.0 E4
NI)
NI)
7 y
ND
3.5 E4
ND
ND
NI)
NI)
ND
-------
TABLE B3. BACTERiAL DATA, EXTENDED TINE STUDIES, pH 8.0, 0.69 to 1.45 INITIAL
C}ILORIIIE RESIDUAL
Run
Temperature
Number
C
p11
20
0
8
24 hr. coiiform,bacteria/mt
4
1
Autoclaved
Sewage
5
10
23 20 8 1
5
10
32 30 8 1
5
10
20 0 8 1
5
10
23 20 8 1
5
10
9 30 8 1
5
10
7
Initial chlorine
residual, mg/i
Free Total
.69 .90
.69 .90
.69 .90
.92 1.13
.92 1.13
.92 1.13
1.25 1.45
1.25 1.45
1.25 1.45
0 .90
0 .90
0 .90
0 1.13
0 1.13
0 1.13
0 .90
0 .90
0 .90
ND
ND
<1.0
El
NI)
ND
ND
ND
<1.0
El
ND
ND
ND
ND
<1.0
El
ND
ND
<1.0
El
ND
<1.0
El
ND
<1.0
l
<1.0
El
ND
<1.0
El
ND
<1.0
El
<1.0
El
ND
<1.0
El
ND
<1.0
El
<1.0
El
<1.0
El
ND
<1.0
El
ND
<1.0 El
1.8 ES
<1.0 El
9.0 E4
ND
ND
<1.0 El
1.3 ES
NI)
ND
Total chlorine
residual
NI)
ND
ND
.63
.41
.23
.48
.13
.02
ND
ND
ND
.85
.59
.34
ND
ND
NI)
Time
0
7.3 E3
3.6 E4
7.3 E4
7.3 E3
3.7 E4
7.3 E4
1.4 E4
6.9 E4
1.4 ES
7.3 E3
3.6 E4
7.3 E4
7.3 E3
3.7 E4
7.4 E4
6.3 E3
3.2 E4
6.3 E4
2 hr.
<1.0 El
3. ]. E4
5.9 E4
<1.0 El
3.4 E2
7.4 E3
<1.0 El
1.5 E2
l.S ES
5.8 E2
1.8 E4
5.5 E4
<1.0 El
7.5 E2
4.8 E3
<1.0 El
1.0 El
6.1 E4
ND ND <1.0 El
ND ND <1.0 El
ND ND <1.0 El
ND l.0 El
ND <1.0 El
ND <1.0 El
ND N !)
ND ND
ND ND
ND <1.0 El
NI) <1.0 El
ND <1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
ND
1.0 El
1.0 El
1.7 ES
NO ND NI)
NI) NI) ND
NI) ND NI)
-------
TABLE B4.
BACTERIAL DATA, EXT NDED TIME STUDIES, pH 8.0, 0.69 to 1.45 INITIAL
CHLORINE RESIDUAL
Run
Number
20
S. typhirnurium, bacteria/mi S. 8Oflflιi, bacteria/mi
6
4 day
ND
ND
ND
5 day
<1.0 El
(1.0 El
<1.0 El
I- ,
a
day 7 day
ND ND
ND NI)
ND III)
ND (1.0 El
ND <1.0 El
ND <1.0 El
<1.0 El ND
<1.0 El ND
l.3E 5 ND
Ti me
0
7.9 El
3.9 E4
1.9 E4
23 7.7 E3
3.4 £4
7.7 £4
32 2.1 £4
1.0 ES
2.1 ES
20 7.9 El
3.9 E4
7.9 £4
23 7.1 E3
3.9 £4
7.7 £4
9 2.1E4
1.0 ES
2.1 £5
ND <1.0 El
ND <1.0 El
ND <1.0 El
<1.0 El ND
<1.0 El ND
1.3 85 ND
7
2 hr.
<1.0 El
1.4 £4
4.5 £4
1.0 El
3.5 81
4.3 El
<1.0 El
<1.0 El
2.9 ES
3.6 £2
1.6 £4
4.6 E4
3.5 El
8.5 El
5.0 E2
(1.0 El
<1.0 El
1.6 ES
24 hr.
ND
ND
ND
<1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
1.5 ES
ND
ND
ND
<1.0 El
<1.0 El
<1.0 81
<1.0 El
<1.0 El
ND
24 hr.
4day
S day
6
ND
ND
<1.0
El
ND
ND
ND
ND
<1.0
El
ND
ND
ND
AD
<1.0
El
ND
ND
<1.0
El
HD
<1.0
El
ND
<1.0
El
<1.0
El
ND
<1.0
El
ND
<1.0
El
<1.0
El
ND
<1.0
El
ND
<1.0
El
<1.0
El
<1.0
El
ND
<1.0
El
ND
<1.0
El
(1.0
El
ND
<1.0
El
ND
Time
0
1.3 E4
6.4 E4
1.3 ES
6.9 El
3.5 £4
6.9 E4
1.9 E4
9.4 E4
1.9 £5
1.3 £4
6.4 £4
1.3 £5
6.9 83
3.3 84
6.9 84
5.7 El
2.8 E4
5.7 E4
2 hr.
<1.0 El
3.6 £4
9.7 E4
<1.0 El
1.0 El
1.3 E3
<1.0 El
<1.0 El
1.9 ES
4.5 £2
1.7 £4
7.8 E4
<1.0 El
<1.0 El
ND
<1.0 El
<1.0 El
4.5 E4
ND
ND
ND
1.0 El
<1.0 El
<1.0 El
ND (1.0 El ND
ND 1.0 El ND
ND <1.0 El ND
ND <1.0 El ND
ND <1.0 El ND
ND <1.0 El ND
1.0 El ND
ND ND
1.4 £6 ND
ND ND (1.0 El
ND NI) <1.0 El
ND ND <1.0 El
NP ND
ND ND
ND ND
ND ND
ND ND
ND ND
ND cl.0 El
ND <1.0 El
ND <1.0 El
ND <1.0 El
ND <1.0 El
ND <1.0 El
(1.0 El
<1.0 El
1.0 El
<1.0 El
<1.0 El
ND
<1.0 El
ND
9.0 E4
ND ND ND
ND ND ND
ND ND ND
-------
I -I
I . )
-1
TABLE B5. VIRAL DATA, EXTENDED TINE STUDIES, pH 8.0, 0.69 to
1.45 INITIAL CHLORINE RESIDUAL
Run
Number
Time
0
2 hr.
f 2,
24 hr.
PFU/ml
4 day
5 day
6 day
7 day
20
8.8 E3
4.4 E4
8.8 E4
2.9 E3
2.6 E4
8.5 E4
ND
ND
ND
ND
ND
ND
5.0 El
5.8 E3
2.7 E4
ND
ND
ND
<1.0 El
3.7 E3
3.1 E4
23
4.4 E3
2.2 E4
4.4 E4
1.1 E2
2.0 E4
3.5 E4
<1.0 El
4.3 E2
8.4 E3
ND
ND
ND
ND
<1.0 El
3.4 E2
ND
ND
ND
<1.0 El
<1.0 El
2.0 E2
32
2.2 E3
1.1 E4
2.2 E4
3.9 E2
4.8 E3
2.1 E4
<1.0 El
1.1 E2
3.6 E3
<1.0 El
<1.0 El
2.2 E2
ND
ND
ND
<1.0 El
<1.0 El
4.5 El
ND
ND
ND
20
8.8 E3
4.4 E4
8.8 E4
7.0 E3
3.7 E4
7.7 E4
ND
ND
ND
ND
ND
ND
1.1 E2
5.0 E3
2.2 E4
ND
ND
ND
<1.0 El
1.4 E3
1.6 E4
23
4.4 E3
2.4 E4
4.4 E4
3.8 E3
1.7 E4
3.9 E4
<1.0 El
4.4 E2
5.9 E3
ND
ND
ND
<1.0 El
<1.0 El
.3.0 El
ND
ND
ND
<1.0 El
<1.0 El
1.0 El
-------
TABLE B6. BACTERIAL.DATA, EXTENDED TIME STUDIES, pH 8.0, 0.21 to 0.37 mg/i INITIAL
CHLORINE RESIDUAL
Run
Temperature
Number
C
pH
26
0
8
coliforsi, bacteria/mi
1
Autoc loved
Spwno. e
Initial
residual,
Free
chlorine
mg/I
Total
24 hr.
Total chlorine
residual
Time
0
2 hr.
24 hr.
4 day
Sday
6day
7day
.1
.23
.35
ND
2.2 E4
6.9 E2
ND
<1.0 El ND
<1.0
El
ND
.2
.23
.35
ND
4.4 E4
1.4 E4
ND
<1.0 El ND
<1.0
El
ND
.5
.23
.35
ND
1.1 ES
7.0 E4
ND
<1.0 El ND
<1.0
El
ND
28
0
8
.1
.2
. 5
.21
.21
.21
.34
.34
.34
ND
ND
ND
2.4 E4
4.8 E4
1.2 ES
<1.0 EL
<1.0 El
3.3 E4
ND
ND
ND
<1.0 El ND
2.0 El ND
<1.0 El ND
ND
ND
ND
<1.0
1.0
<1.0
El
El
El
25
20
8
.1
.5
1.0
.25
.25
.25
.37
.37
.37
.14
.15
.14
4.8 E4
2.4 E5
4.8 ES
<1.0 El
1.4 E3
2.8 ES
26
0
8
.01
.05
.20
0
0
0
.35
.35
.35
ND
ND
ND
1.6 ES
8.0 E4
1.6 ES
1.1 E4
5.0 E4
1.0 ES
28
0
8
.01
.05
.10
0
0
0
.34
.34
.34
ND
ND
ND
1.6 £4
8.0 £4
1.6 ES
1.4 £4
6.5 £4
1.4 ES
5
20
6
.01
.05
.10
0
0
0
.23
.23
.23
.17
.16
.16
1.4 £3
7.2 £3
1.4 £4
1.1 £2
7.5 £2
1.1 £3
<1.0
<1.0
<1.0
El
El
El
ND
ND
ND
ND
ND
NI)
ND
ND
ND
ND
ND
ND
25
20
8
.01
.05
.10
0
0
0
.37
.37
.3?
.30
.20
.23
2.4 £4
1.2 ES
2.4 £5
4.1 £2
1.7 £3
4.0 £3
1.0
<1.0
<1.0
El
El
El
ND
NI)
ND
MD
NI)
ND
<1.0
<1.0
<1.0
El
El
El
ND
NI)
NO
ND ND <1.0 El
ND ND <1.0 El
ND ND <1.0 El
<1.0 El
<1.0 El
<1.0 El
ND
ND
ND
ND
ND
ND
ND
ND
ND
<1.0 El
<1.0 El
<1.0 El
<1.0 El
1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
ND
ND
ND
ND
ND
ND
<1.0 El
1.0 El
<1.0 El
ND ND
NI) ND
NI) ND
-------
TABLE B-7.
BACTERIAL DATA, EXTENDED TINE STUDIES, p11 8.0, 0.21 to 0.37 ing/l INITIAL
CHLORINE RESIDUAL
26
2.6 E4
5.2 E4
1,3 15
28 2.8 E4
5.6 14
1.4 15
4.0 El ND -1.0 El
1.2 13 Nt) <1.0 El
3.5 13 ND -1.0 El
Run
T1TT
3.
phirawjzvn,
bacteria/mi
T Ime
.
aonnei,
bacteria/mi
Number
0 2
hr. 24
hr.
4 day
5
day
6 day 7 day
0 2 hr.
24 hr. 6 day
5
day
6
day 7 day
<1.0 El ND
-1.0 Ii NI)
7.5 13 ND
NI) -1.0 El Nil
ND <1.0 El ND
ND <1.0 11 ND
ND ND <1.0 Ii
ND ND <1.0 El
ND ND <1.0 El
<1.0 El
<1.0 El
-1.0 El
1.5 14
3.0 14
7.5 E4
<1.0 El
1.0 12
1.0 E3
25 4.0 16 <1.0 11 <1.0 El ND ND <1.0 El ND
2.0 15 Li 13 1.0 El ND Nt) <1.0 11 ND
4.0 ES 8.0 14 1.0 El NI) ND <1.0 El ND
ND <1.0 El
ND <1.0 El
ND <1.0 El
ND <1.0 El
ND <1.0 El
ND <1.0 El
26 L5 14 5.2 13 ND <1.0 El
7.5 14 32 E6 Ni) -1.0 11
1.5 15 8.9 14 ND <1.0 El
ND <1.0 El ND
ND <1.0 El ND
ND <1.0 El ND
ND ND <1.0 El
ND ND <1.0 El
ND ND <1.0 El
28 1.3 E4 1.6 14
6.5 V.4 5.1 14
1.3 ES 1.8 E5
<1.0 El
<1.0 El
<1.0 El
ND
ND
N I)
ND
ND
ND
ND <1.0 11
ND <1.0 11
ND <1.0 El
ND ND <1.0 El
ND ND <1.0 El
ND ND <1.0 El
<1.0 El ND
-1.0 El ND
<1.0 El ND
NI) <1.0 El
ND <1.0 El
ND <1.0 El
ND ND
ND ND
ND ND
1.6 14 <1.0 El
3.2 14 <1.0 El
1.6 15 9.0 13
4.3 14 <1.0 El
2.2 ES ND
6.3 ES 1.0 15
1.6 14 4.9 E3
8.0 E4 3.4 E4
1.6 ES 1.5 E4
1.0 14 1.3 E4
5.0 E4 2.7 14
1.0 ES 7.0 E4
1.7 13 1.9 E2
8.4 13 1.1 El
1.7 14 2.0 E3
1.9 14 1.5 El
9.5 14 2.5 12
1.9 ES 6.0 12
5 2.8 E3 3.9 12 <1.0 El
1.4 14 2.7 E3 <1.0 El
2.8 14 4.8 El <1.0 El
25 2.3 E4 4.5 El <1.011
1.2 1.5 1.3 El <1.0 El
2.3 15 6.0 12 <1.0 El
ND
ND
ND
ND
ND
ND
ND ND
ND ND
ND ND
ND <1.0 El
ND <1.0 El
ND <1.0 El
ND <1.0 El
ND <1.0 El
ND <1.0 El
ND <1.0 El
NI) <1.0 El
NI) <1.0 El
ND ND <1.0 El
ND NI) <1.0 El
NI) NI) <1.0 El
ND ND <1.0 El
NI) ND <1.0 El
ND ND <1.0 El
ND
ND
ND
<1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
ND ND ND ND
ND ND NI) ND
ND NI) NI) ND
ND ND <1.0 El ND
ND ND <1.0 El ND
ND ND <1.0 El ND
-------
0
TABLE B8. VIRAL DATA, EXTENDED TIME STUDIES, pH 8.0, 0.21 ta
0.37 mg/i INITIAL CHLORINE RESIDUAL
Run
Number
Time
0
2 hr.
f2,
24 hr.
PFU/ml
4 day 5 day
6 day
7 day
26
6.5 E3
1.3 E4
3.3 E4
1.1 E3
7.1 E3
1.4 E4
ND
ND
ND
<1.0 El
1.6 E2
2.4 E2
ND
ND
ND
<1.0 El
3.0 El
2.0 El
ND
ND
ND
28
2.3 E3
4.6 E3
1.2 E4
<1.0 El
4.3 E2
8.2 E3
ND
ND
ND
<1.0 El
<1.0 El
7.6 E2
ND
ND
ND
ND
ND
ND
<1.0 El
<1.0 El
1.0 E2
25
4.0 E3
2.0 E4
4.0 E4
<1.0 El
1.2 E4
3.3 E4
<1.0 El
3.4 E2
3.9 E3
ND
ND
ND
ND
ND
ND
<1.0 El
<1.0 El
<1.0 El
ND
ND
ND
26
5.5 E2
2.8 E3
5.5 E3
4.6 E2
2.2 E3
5.3 E3
ND
ND
ND
<1.0 El
2.5 El
1.0 E2
ND
ND
ND
ND
ND
ND
ND
ND
ND
28
2.3 E2
1.2 E3
2.3 E3
2.8 E2
1.0 E3
2.8 E3
ND
ND
ND
2.5 El
1.7 E2
4.5 E2
ND
ND
ND
ND
ND
ND
<1.0 El
<1.0 El
1.2 E2
25
4.0 E2
2.0 E3
4.0 E3
1.8 E2
1.4 E3
2.9 E3
<1.0 El
<1.0 El
<1.0 El
ND
ND
ND
ND
ND
ND
<1.0 El
<1.0 El
<1.0 El
ND
ND
ND
-------
TABLE B9.
BACTERIAL DATA, EXTENDED TIME STUDIES, pH 6.0, .75 to 1.45 INITIAL
CHLORINE RESIDUAL
o .88
o .88
o .88
o 1.15
o 1.19
o 1.15
o .90
0 .90
0 .90
1.05
77
44
89
Si
23
ND
N))
NI)
<1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 11
5
ND ND ND <1.0 El
ND ND ND <1.0 El
ND ND ND <1.0 El
ND ND NI) <1.0 El
ND ND NI) <1.0 El
ND NI) ND <1.0 El
Run
Temperature
Number
C
p)l
19
0
6
H
H
X
Autoclaved
Sewage
Initial
residual,
Free
chlorine
mg/I
Total
24 hr.
Total chlorine
residual
1
.75
.91
.71
5
.75
.91
.45
10
.75
.91
.25
coliform, bacteria/ml
.92 1.15
.92 1.15
.92 1.15
1.26 1.45
1.26 1.45
1.26 1.45
Time
0
1.2 E4
5.9 E4
1.2 ES
9.4 E3
4.7 14
9.4 14
1.6 E4
7.9 E4
1.6 ES
day 6 day
ND ND
ND ND
ND ND
.62
32
11
.46
.10
0
22 20 6 1
5
10
32 30 6 1
S
10
19 0 6 1
S
10
22 20 6 1
5
10
9 30 6 1
5
10
7 day
<1.0 El
<1.0 El
<1.0 El
2 hr.
24 hr.
4
day______
<1.0 El <1.0 El
ND
<1.0 El <1.0 El
ND
8.3 E3 <1.0 El
ND
<1.0 El <1.0 El
ND
ND
ND
<1.0
El
<1.0 El <1.0 El
ND
ND
ND
<1.0
El
<1.0 El <1.0 El
ND
ND
ND
<1.0
El
<1.0 El <1.0 El
<1.0
El
ND
<1.0
El
ND
<1.0 El <1.0 El
<1.0
El
ND
<1.0
El
ND
8.7 14 9.5 14
5.3 14
ND
5.0 14
ND
1.2 E4 <1.0 El
5.9 E4 <1.0 11
1.2 ES 9.0 El
9.4 £3 <1.0 El
4.7 1.4 <1.0 El
9.4 1.4 <1.0 El
6.3 113 <1.0 El
3.2 114 <1.0 El
6.3 14 5.8 114
<1.0 El
<1.0 El
ND
<1.0 El
ND
6.0 ES
ND ND ND
NI) ND NI)
ND ND ND
-------
TABLE Bb. BACTERIAL DATA, EXTENDED TIME STUDIES, pH 6.0, .75 to 1.45 INITIAL
CHLORINE RESIDUAL
ND ND ND <1.0 El
ND ND ND <1.0 El
NI) NI) NI) <1,0 El
Run
Number
19
5
3. jpAisimirti n, bacterlii/ml S. nonnei, bacterIa/mi
Time
4 dny
ND
RD
ND
day 6 day
NI) ND
NO ND
NI) NI)
7 day
<1.0 El
<1.0 Cl
<1.0 El
<1.0 El
<1.0 El
<1.0 El
ND ND ND
ND ND ND
ND ND ND
Time
0
1.4 E4
6.9 £4
1.4 ES
22 1.4 £4
6.9 £4
1.4 ES
32 2.1 E4
1.0 ES
2.1 ES
19 1.4 £4
6.9 £4
1.4 ES
22 1.6 £6
6.9 £4
1.4 ES
9 2.1 £4
1.0 ES
2.1 ES
4 day
ND
ND
ND
6
S day
ND
ND
ND
2 hr.
1.0 El
<1.0 £1
8.3 £3
1.0 El
<1.0 El
3.5 El
<1.0 El
<1.0 El
1.1 £5
<1.0 El
<1.0 El
1.3 £2
<1.0 El
<1.0 El
<1.0 El
-1.0 El
1.0 El
1.4 ES
24 hr.
1.0 El
1.0 Cl
1.0 El
1.0 El
<1.0 El
<1.0 El
1.0 El
<1.0 El
1.1 ES
<1.0 El
1.0 El
1.0 El
ND
ND
NI)
1.0 El
1.0 El
ND
ND
ND
ND
day 7 day
ND <1.0 El
ND <1.0 El
ND <1.0 El
<1.0 El ND
<1.0 El ND
4.3 £4 ND
<1.0 El
1.0 El
1.9 E5
NI)
ND
ND
ND ND ND <1.0 El
ND ND ND <1.0 El
ND ND ND <1.0 El
ND ND
ND NI)
ND ND
0
1.3 E4
6.4 £4
1.3 ES
1.2 E4
5.9 E4
1.2 ES
2.7 £4
1.3 ES
2.7 £5
1.3 £4
6.4 E4
1.3 £5
1.2 £4
5.9 £4
1.2 ES
5.7 E3
2.8 £4
5.7 £4
<1.0 El
<1.0 El
1.0 El
2 hr.
<1.0 El
<1.0 El
7.0 £3
<1.0 El
1.0 El
<1.0 El
1.0 El
1.0 El
1.4 £5
<1.0 El
1.0 El
<1.0 El
<1.0 El
<1.0 El
1.0 El
<1.0 El
1.0 El
5.5 Eli
<1.0 El
<1.0 El
2.8 £5
24 hr.
<1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
3.4 ES
1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 £1
1.0 El
1.0 Cl
<1.0 El
NI)
ND <1.0 El
ND <1.0 El
ND 4.7E4
NI) ND ND <1.0 El
ND ND ND 1.0 El
MD ND NI) <1.0 El
ND
ND
NI)
<.1.0 El
<1.0 El
<1.0 El
1.0 El
ND
9.1 ES
ND ND ND
ND ND <1.0 El
ND ND ND
NI)
ND
NI)
NI) N?)
ND ND
ND NT)
-------
TABLE B-li. VIRAL DATA, EXTENDED TIME STUDIES, pH 6.0, .75. to 1.45
INITIAL CHLORINE RESIDUAL
Run
Number
Time
0
2 hr.
f 2,
24 hr.
PFU/ml
4 day 5 day
6 day
7 day
19
7.0 E3
6.0 El
ND
ND
ND
ND
<1.0 El
3.5 E4
6.7 E3
ND
ND
ND
ND
7.3 E2
7.0 E4
3.4 E4
ND
ND
ND
ND
1.2 E4
22
8.4 E3
<1.0 El
<1.0 El
ND
ND
NI)
<1.0 El
4.2 E4
4.8 E3
1.4 E2
ND
ND
NI)
<1.0 El
8.4 E4
4.1 E4
7.2 E3
ND
ND
ND
3.9 E3
32
4.2 E3
1.0 El
<1.0 El
<1.0 El
ND
<1.0 El
ND
2.1 E4
1.6 E3
1.0 El
<1.0 El
ND
<1.0 El
ND
4.2 E4
2.3 E4
1.9 E4
1.7 E4
ND
3.3 E3
ND
19
7.0 E3
5.4 E3
ND
ND
ND
MD
<1.0 El
3.5 E4
2.4 E4
ND
ND
ND
ND
1.3 E3
7.0 E4
5.8 E4
ND
ND
ND
ND
6.9 E3
22
8.4 E3
2.8 E3
8.0 El
ND
ND
ND
<1.0 El
4.2 E4
1.4 E4
5.8 E2
ND
ND
MD
<1.0 El
8.4 E4
3.5 E4
2.2 E3
ND
ND
ND
2.1 E2
-------
TABLE B12. BACTERIAL DATA, EXTENDED TINE STUDIES, pH 6.0, 0.18 to 0.38 INITIAL
CHLORINE RESIDUAL
o .30
0 .30
0 .30
Run
Temperature
Number
C pH
z
Autoclaved
Sewage
.2
.5
H
L )
24 hr.
Total chlorine
residual
.23
.23
.23
.22
.18
.15
.37
35
34
Initial chlorine
realdual, mg/i
Free Total
.28 .38
.28 .38
.28 .38
.18 .30
.18 .30
.18 .30
0 .38
o .38
o .38
0 .23
0 .23
0 .23
bacteria/mi
4day Sday
ND ND
NO ND
ND ND
Time
0
2.1 E4
4.2 E4
1.1 E5
1.7 84
8.5 E4
1.7 E5
2.3 84
1.2 ES
2.3 ES
7
24 20 6 .1
.5
1.0
27 0 6 .01
.05
.10
5 20 6 .01
.05
.10
24 20 6 .01
.05
.10
6 day
<1.0 El
<1.0 El
<1.0 El
day
ND
ND
ND
2 hr.
<1.0 El
<1.0 El
1.0 El
<1.0 El
1.0 El
<1.0 El
2.0 El
1.1 E3
1.1 83
<1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
colt form,
24 hr.
<1.0 El
1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
<1.0 El
1.0 El
<1.0 El
<1.0 El
<1.0 El
ND 1.2 E3
.12 6.0 E3
.11 1.2 E4
.33 2.1 E4
.32 1.1 ES
.32 2.1 E5
ND ND ND ND
ND ND ND ND
ND ND ND NO
ND ND <1.0 El ND
ND ND <1.0 El ND
ND ND <1.0 El NO
ND NO ND ND
NI) NI) ND ND
ND ND ND ND
ND ND ND ND
ND ND NO ND
NO ND ND NO
-------
- I
U,
TABLE B13. BACTERIAL DATA, EXTENDED TIME STUDIES, pH 6.0, 0.18 to 0.38 INITIAL
CHLORINE RESIDUAL
Run
Number
Time
0
2 hr.
5. typhz.rnurisvn,
21. hr. 4 day
bacteria/mi
5 day
6 day 7 day
rime
0
2 hr.
24 hr.
$.
4 day
sennei,
5 day
bacteria/mi
& day
7 day
27
3.1 14
<1.0 El
<1.0 El
NI)
ND
<1.0 El
ND
1.1 14
<1.0 El
<1.0 El
ND
ND
<1.0 El
ND
6.2 14
<1.0 El
<1.0 El
ND
ND
<1.0 El
ND
2.2 E4
<1.0 El
<1.0 El
ND
ND
-1.0 El
ND
1.6 ES
<1.0 El
<1.0 11
ND
ND
<1.0 El
ND
5.5 14
<1.0 El
<1.0 El
ND
ND
<1.0 El
ND
24
2.6 E4
<1.0 Iii
<1.0 El
ND
NI)
ND
ND
9.0 E3
<1.0 El
<1.0 El
ND
ND
ND
ND
1.3 E5
2,0 El
<1.0 El
ND
ND
ND
ND
4.5 E4
<1.0 El
<1.0 El
ND
ND
NI)
ND
2.6 ES
1.9 12
-1.0 El
NI)
N !)
NI)
ND
9.0 14
<1.0 El
<1.0 El
ND
NI)
ND
NI)
27
2.4 E4
9.0 II
<1.0 El
NI)
ND
<1.0 El
ND
1.3 E4
<1.0 El
<1.0 El
ND
NI)
<1.0 El
ND
1.2 ES
2.2 E2
<1.0 El
ND
Ni)
<1.0 El
ND
6.5 E4
1.5 El
<1.0 El
ND
ND
<1.0 El
ND
2.4 ES
2.0 F,3
<10 El
ND
NI)
<1.0 El
ND
1.3 15
Nfl
<1.0 El
ND
ND
<1.0 El
NI)
5
1.9 E3
<1.0 El
<1.0 El
ND
ND
ND
ND
1.5 E3
<1.0 El
<1.0 El
ND
NI)
NI)
ND
9.6 13
<1.0 11
<1.0 El
ND
NI)
NI)
NI)
7.6 El
<1.0 El
<1.0 El
ND
ND
NI)
ND
1.9 14
1.7 12
<1.0 El
ND
ND
ND
ND
1.5 14
1.0 E3
<1.0 El
ND
ND
ND
NO
24
3.0 E4
<1.0 11
<1.0 El
ND
NI)
ND
NI)
1.8 E4
<1.0 El
<1.0 El
ND
ND
NI)
NI)
1.5 ES
-1.0 El
<1.0 El
ND
ND
ND
ND
9.0 E4
<1.0 El
<1.0 El
ND
NI)
NI)
NI)
3.0 1, 5
<1.0 El
<1.0 II
ND
ND
ND
ND
1.8 E5
<1.0 11
<1.0 El
ND
NI)
ND
ND
-------
a
TABLE B14. VIRAL DATA, EXTENDED TINE STUDIES, pH 6.0, 0.18
to 0.38 INITIAL CHLORINE RESIDUAL
Run
Number
Time
0
2 hr.
f2,
24 hr.
PFU/ml
4 day
5
day
6 day 7 day
27
5.6 E3
1.1 E4
2.8 E4
<1.0 El
1.0 El
1.5 E2
<1.0 El
<1.0 El
1.5 El
ND
ND
ND
ND
ND
ND
<1.0 El
<1.0 El
<1.0 El
ND
ND
ND
24
6.2 E3
3.1 E4
6.2 E4
1.0 E2
4.8 E3
1.1 E4
<1.0 El
5.8 E2
2.6 E3
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
27
5.6 E2
2.8 E3
5.6 E3
4.7 E2
1.3 E3
5.0 E3
7.0 El
3.7 E2
5.7 E2
ND
ND
ND
ND
ND
ND
1.0 El
5.5 El
8.5 El
ND
ND
ND
24
6.2 E2
3.1 E3
6.2 E3
2.7 E2
1.3 E3
2.6 E3
2.0 El
<1.0 El
1.9 E2
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
-------
I-
(j
TABLE B15. VIRAL DATA, EXTENDED TIME STUDIES, DECHLORINATED
CONTROLS
Run
Number
Time
0
2 hr.
f2,
24 hr.
PFU/ml
4 day
5 day
6 day
7 day
26
5.5 E3
5.5 E3
ND
3.0 E3
ND
2,4 E3
ND
28
25
2.3 E3
4.0 E3
2.3 E3
4.0 E3
ND
3.3 E3
3.6 E3
ND
ND
ND
ND
3.9 E2
2.0 E3
ND
27
5.6 E3
5.6 E3
5.3 E3
ND
ND
4.2 E3
ND
24
6.2 E3
6.2 E3
5.2 E3
ND
ND
ND
NI)
20
8.5 E4
8.5 E4
ND
ND
4.1 E3
ND
ND
23
4.4 E4
4.4 E4
3.7 E5
ND
1.9 E4
ND
1.9 E4
32
2.2 E4
2.2 E4
7.2 E3
3,2 E4
ND
1.8 E2
ND
22
8.5 E4
8.5 E4
5.0 E4
ND
ND
ND
7.1 E4
32
4.2 E4
4.2 E4
3.3 E4
3.4 E4
ND
2.3 E4
ND
-------
APPENDIX C. RESERVOIR DATA
TABLE C-i. BACTERIAL AND VIRAL INACTIVATION, RESERVOIR STUDIES
Water Source Z Sewage
Added
Time. Free Ci ,
1inutes pH mg/i
Total Ci
mg/i
f2
log N/No
Coliforin
log N/No
Turbidity
NTU
!lun
#
tap 2 0 8.4 1.5 2.1 .38 5
10 8.6 .02 1.7 1.5 .8 1.2
30 8.4 .02 1.7 < 3.7 1.7 1.0
60 8.5 .2 1.6 < 3.7 2.4 .7
90 8.5 .4 1.4 < 3.7 2.4 .7
120 8.6 .5 1.3 < 3.7 1.5 .7
tap 2 0 8.5 .8 2.0 .58 5
10 8.5 .01 1.7 1.5 .8 1.1
30 8.5 .04 1.7 < 3.7 .7 1.0
60 8.5 .2 1.6 < 3.7 2.6 .9
90 8.5 .4 1.4 < 3.7 2.6 .8
120 8.5 .5 1.3 < 3.7 2.0 .7
rap: river 2 0 7.2 1.6 2.2 4.0 5
1:1 mixture 10 7.3 .06 2.0 1.3 1.5 4.3
30 7.4 .06 1.7 < 3.7 1.8 3.8
60 7.5 .1 1.1 3.7 2.3 4.0
90 7.5 .2 .9 < 3.7 2.6 3.7
120 7.6 .3 .9 < 3.7 3.2 3.8
tap: river 2 0 8.3 1.6 2.1 5
1:1 mIxture 10 7.1 .07 1.9 1.0 .1 4.6
30 7.1 .1 1.7 < 3.7 1.5 3.9
60 7.2 .2 1.2 < 3.7 2.6 3.5
90 7.3 .2 1.0 < 3.7 2.8 4.0
120 7.3 .4 .9 < 3.7 2.5 4.0
river 2 0 6.7 1.6 2.7 7.3 5
10 6.9 .2 2.1 1.9 1.7 5.9
30 6.8 .2 2.0 < 3.7 1.8 6.0
60 6.9 .3 1.6 < 3.7 2.6 6.0
90 6.9 .4 1.1 < 3.7 < 3.4 5.9
120 7.1 .5 1.0 < 3.7 2.6 6.5
5.9 5
river 2 0 6.7 1.7 2.6 2.1 .5 6.3
10 6.7 .2 2.1 3.5 2.4 5.8
30 6.7 .3 2.1 < 3.7 3.1 5.9
60 6.8 .3 1.9 < 3.7 < 3.4 6.8
90 6.9 .4 1.1 < 3.7 C 3.4 6.6
120 6.9 .5 .9
138
-------
TABLE C2. BACTERIAL AND VIRAL INACTIVATION, RESERVOIR STUDIES
Water Source Z Sewage
Added
Time, Free Cl.
Minutes pH mg/i
Total Cl
mg/i
f2
log N/No
Coliform
log N/No
Turbidity
NTU
Run
U
tap 1 .0 8.2 .41 .85 2
10 8.4 0 .62 :7 .2 2.5
30 8.4 0 .67 .8 1.2 1.5
60 8.4 0 .67 1.4 1.9 1.5
90 8.4 0 .72 2.2 2.7 1.5
120 8.3 0 .70 < 5.1 3.2 1.2
tap 5 0 8.2 .38 .79 3.3 2
10 8.1 0 .35 .6 .3 3.4
30 8.2 0 .37 .8 .6 2.9
60 8.2 0 .48 .9 1.5 2.4
90 8.1 0 .74 1.3 1.6 2.0
120 8.2 .62 1.3 1.8
tap 10 0 8.2 .52 .93 .6 .2 5.3 2
10 8.1 0 .14 .6 .8 5.1
30 8.0 0 .21 .8 .8 4.2
60 8.1 0 .39 1.0 2.0 3.1
90 8.1 0 .49 1.1 2.0 2.8
120 8.1 0 .55
tap 1 0 8.2 0 1.5 2
10 8.3 1.3 .6 .9 2.0
30 8.4 1.4 1.0 2.0 2.0
60 8.4 1.4 1.4 3.4 1.3
90 8.3 1.4 1.7 4.0 1.1
120 8.3 1.4 3.0 4.0 1.1
tap 5 0 8.3 0 1.5 2
10 8.2 1.0 .7 .6 3.4
30 8.2 1.1 .8 1.6 3.1
60 8.2 1.1 1.1 2.3 2.3
90 8.2 1.3 1.3 3.4 1.9
120 8.2 1.3 1.5 3.5 1.7
tap 10 0 8.3 0 1.5 2
10 8.2 .7 .5 :6 5.2
30 8.2 .7 .7 1.7 4.8
60 8.2 .7 1.1 2.4 3.5
90 8.2 .9 1.5 2.5 3.0
120 8.2 1.0 1.4 3.1 2.5
139
-------
TABLE C3. BACTERIAL AND VIRAL INACTIVATION, RESERVOIR STUDIES
Water Source 2 Sewage
Added
Time, Free Cl,
Minutes pH mg/i
Total Ci
mg/i
f2
log N/No
Coliform
log N/No
Turbidity
NTU
Run
#
tap
tap
tap: river
1:1 mixture
tap: river
1:1 mixture
iv.r
river
1
1
1
I
1
1
0
8.1
0
2.0
.8
4
10
8.2
1.8
.5
.5
2.0
30
8.1
1.9
.3
.3
1.5
60
8.2
1.8
2.4
2.4
1.2
90
7.9
1.9
2.9
2..9
1.1
120
8.1
1.8
2.7
2.7
1.0
0
8.1
0
2.0
1.0
4
10
7.6
1.9
.7
2.0
30
8.1
1.9
.3
1.1
1.6
60
8.0
1.9
.9
2.1
1.3
90
8.0
1.9
.8
1.6
1.2
120
8.0
1.9
1.3
2.2
1.1
0
7.5
0
1.6
115
4
10
7.5
1.4
0
.7
120
30
7.4
1.4
0
1.3
100
60
7.5
1.3
.2
1.8
110
90
7.4
1.3
.3
2.5
110
120
7.5
1.4
.3
<
2.7
110
0
7.3
0
1.5
145
4
10
7.3
1.4
.3
.5
120
30
7.3
1.4
.2
1.3
105
60
7.2
1.4
.3
2.6
110
90
7.3
1.3
.3
2.1
110
120
7.3
1.4
.3
2.2
110
0
7.2
0
1.3
200
4
10
7.2
1.1
.1
.4
30
7.3
1.1
0
1.4
200
60
7.2
.9
.1
2.1
200
90
7.1
1.0
.2
2.5
200
120
7.1
.9
.2
.9
200
0
7.0
0
1.3
200
4
10
7.0
1.1
.1
0
200
30
7.0
1.1
.1
1.3
190
60
7.0
1.0
.2
2.4
90
120
7.1
6.9
.9
.9
.3
.3
1.8
1.5
190
140
-------
TABLE C4. BACTERIAB AND VIRAL INACTIVATION, RESERVOIR STUDIES
1
Sewage
Time,
Free Cl,
Total Cl
f2
Coliform
Turbidity
Run
Water Source Added
Minutes pR mg/i
mg/i
log N/No
log
N/No
NTIJ
I
tap 1 0 8.0 0 1.3 .8 8
10 8.1 1.2 .6 0 1.1
30 8.1 1.2 1.2 .8 1.6
60 8.1 1.2 1.4 3,3 2.0
90 8.1 1.2 2.3 3.3 .7
120 8.1 1.2 3.1 3.8 .7
tap 1 0 0 .8 8
10 8.1 1.2 .8 0 1.1
30 8.1 1.2 1.1 1.4 1.0
60 8.1 1.2 1.4 1.6 1.1
90 8.1 1.2 1.9 3.5 .8
120 8.1 1.2 2.5 4.1 .8
cap: river 1 0 7.9 0 1.2 4.8 8
1:1 mixture 10 8.0 1.1 .5 0 3.2
30 7.8 1.1 .8 .5 4.3
60 8.0 1.1 .9 1.4 4.4
90 7.9 1.1 1.0 2.5 4.1
120 8.0 1.1 .9 3.5 4.1
tap: river 1 0 0 4.5 8
1:1 mixture 10 8.0 1.1 .6 0 3.9
30 8.1 1.1 .7 .9 4.6
60 8.0 1.1 .6 2.2 3.0
90 8.1 1.1 .9 2.8 4.0
120 8.0 1.1 .9 3.4 3.9
river 1 0 7.8 0 1.2 8.5 8
10 8.0 1.0 .4 .2 5.0
30 8.0 1.0 .7 .7 6.9
60 8.0 1.1 .6 1.8 7.6
90 7.9 1.0 .8 2.5 6.8
120 8.0 1.0 .8 2.8 6.6
river 1 0 0 8
10 8.0 1.0 .3 0 5.8
30 8.0 1.0 .6 .5 6.1
60 7.9 1.0 .5 1.7 7.9
90 8.0 1.0 .7 2.3 7.2
120 8.0 1.0 .7 3.5 7.9
141
-------
APPENDIX D. MUNICIPAL DISTRIBUTION SYSTEM DATA
TABLE D-1. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION1.- FREDERICK
Teu p.
week of pH C
Turbidity
NTU
free Cl
mg/i
Total Cl
mg/i
P1
48
ate Count
hr. 35C
Plate
96 hr.
Count
35 C
Plate
9 day
Count
20 C
coliforin
MPN/l00 C
7/25/77 7.8 8.0 2900 4600 >2400
8/ 3. 7.6 3.5 .20 36 50 1800 <2.0
8/8 7.3 5.2 .30 .60 180 190 1300 <2.0
8/15 7.7 8.0 .10 .90 - 1800 2900 <20
8/22 8.6 8.8 .40 3.0 - 440 740 <2.0
8/29 7.4 1.9 .15 .70 75 120 98 <2.0
9/5 8.2 26.0 13.0 .50 1.8 - 1800 3400 <2.0
9/12 7.6 3.3 80 320 iQO o <2.0
9/19 7.8 24.5 1.8 .20 1.40 85 120 380 <2.0
9/26 8.6 23.0 8.5 1.0 2.4 130 160 1200 <2.0
10/3 7.6 22.0 12.0 .90 1.0 560 1200 <2.0
10/10 7.7 19.0 1.0 .20 1.0 6000 8500 8400 <2.0
10/17 9.0 18.0 2.0 .30 2.4 93 100 61 <2.0
10/24 7.3 16.0 1.1 .55 .80 <1.0 2.0 31 <2.0
10/31 8.6 15.5 11.0 .30 3.0 31 39 65 <2.0
11/7 9.0 15.5 1.7 .15 1.5 15 16 160 <2.0
11/14 9.4 12.0 11.0 .35 3.0 24 35 50 <2.0
11/28 8.9 9.0 .84 .15 1.6 <1.0 3.5 11 <2.0
12/5 9.5 9.0 1.4 .20 2.0 5.5 6.0 11 <2.0
12/12 9.3 5.5 .95 .30 1.6 11 15 12 2.0
12/19 8.7 7.5 3.4 .25 3.0 7.0 11 21 <2.0
1/2/78 9.3 6.0 .68 .35 3.0 1.5 4.0 4.5 <2.0
1/9 9.4 4.0 1.1 .30 2.0 2.0 6.5 13 <2.0
1/23 9.4 4.0 .93 .20 2.0 5.5 5.5 20 <2.0
1/30 9.4 4.5 1.1 .30 3.0 5.0 11 8.0 <2.0
2/13 9.3 4.5 1.5 .30 3.0 2.5 4.5 6.5 <2.0
2/20 9.2 3.5 .75 .30 2.0 7.0 13 9.0 49
2/27 9.2 4.0 .91 .40 3.0 4.5 8.5 6.0 <2.0
3/6 9.2 3.5 5.0 .20 2.4 40 59 230 170
3/13 9.0 5.5 2.4 .15 2.0 7.5 7.5 10 2.0
3/20 9.1 6.0 .89 .30 2.0 8.5 14 8.0 <2.0
3/27 8.4 8.0 2.9 .25 2.8 51 71 290 <2.0
4/3 8.1 9.0 1.5 .15 2.0 4.0 7.5 7.0 <2.0
4/10 8.4 11.0 1.1 .15 3.0 4.0 4.5 13 <2.0
3.8 .31 2.1 441 852
ltd. d.v. 3.8 .20 .80 1510 1734
142
-------
TABLE D2. BIOLOGICAL, CHEMICAL 1 AND PHYSICAL DATA, STATION 2 FREDERICK
Temp. Turbidity free Ci Total Cl Plate Count Plate Count Plate Count coliform
Week of p8 C NTU mg/i mg/i 48 hr. 35 C 96 hr. 35C 9 day 20CC MPN/l00 ml
7/25/77 8.4 - 2.6 230 240 79 <2.0
8/1 8.6 2.4 .30 1.0 1.0 1.5 (2.0
8/8 8.2 1.5 .35 3.0 9.0 11 23 <2.0
8/15 9.1 1.4 3.0 3.6 3.0 1.5 (2.0
8/22 9.3 2.0 .60 1.5 - 4.0 20 <2.0
8/29 9.0 1.3 .30 3.6 3.5 6.0 2.5 <2.0
9/5 9.7 24.5 1.0 .30 3.2 38 47 62 <2.0
9/12 9.1 1.3 3.5 4.5 6.5 <2.0
9/19 23.5 1.5 .5 ° 2.2 3.5 &5 3.5 <2.0
9/26 9.4 22.0 1.1 .25 2.8 3.5 4.0 6.0 <2.0
10/3 9.5 20.0 1.0 .35 2.4 4.0 3.0 <2.0
10/10 9.7 20.0 1.6 .20 3.6 4.5 4.5 1.0 <2.0
10/17 9.6 15.0 1.6 .30 2.4 10 10 6.0 <2.0
10/24 9.5 17.0 1.4 .30 3.2 1.0 3.0 2.0 2.0
10/31 7.8 14.5 .88 3.0 4.0 1.0 1.0 3.5 <2.0
11/7 7.8 17.0 .47 .30 .55 4.0 4.5 6.5 <2.0
11/14 9.5 12.0 1.3 .30 3.0 1.0 10 5.5 <2.0
11/28 9.1 9.0 .65 .15 2.0 3.5 5.0 6.5 <2.0
12/5 9.4 8.5 .96 .30 3.0 8.0 10 5.0 <2.0
12/12 8.7 5.0 .61 .50 2.0 6.5 7.5 6.0 <2.0
12/19 8.9 8.0 1.0 .35 4.0 4.0 8.0 9.5 <2.0
1/2/78 9.3 5.5 .79 .50 3.0 3.0 7.0 <2.0
1/9 9.4 4.5 1.4 .50 3.0 7.5 8.0 15 <2.0
1/23 9.5 4.0 .72 .30 2.8 1.5 1.5 7.0 <2.0
1/30 9.5 4.5 .92 .55 3.0 5.5 12 11 <2.0
2/13 9.4 4.5 1.5 .35 3.0 4.0 5.0 3.5 <2.0
2/20 9.4 3.5 .78 .10 2.0 1.0 1.0 4.0 <2.0
2/27 9.2 4.0 .68 .55 2.8 1.0 2.5 6.0 <2.0
3/6 9.3 3.0 .84 .30 3.0 2.0 3.0 8.0 <2.0
3/13 7.5 5.5 1.2 .15 2.0 2.5 8.5 7.0 <2.0
3/20 9.1 6.5 .91 .50 3.0 4.5 5,0 7.5 <2.0
3/27 8.3 8.0 1.1 .35 2.2 4.5 5.5 16 <2.0
4/3 8.4 8.0 1.2 .20 2.2 7.0 8.0 13 <2.0
4/10 9.1 12.0 .94 .55 2.2 6.5 10 10 <2.0
mean 1.2 .52 2.7 14 11
std. dev. .48 .66 .74 41 16
143
-------
TABLE D3. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 3 - FREDERICK
Temp. Turbidity free Cl Total Cl Plate Count Plate Count Plate Count coliform
Week of pH C NTU mg/i mg/i 48 hr. 35C 96 hr. 35C 9 day 20CC HFN/100
7/25/77 8.7 2.0 3.5 11 23 <2.0
8/1 7.9 3.5 .30 1.5 2.0 14 <2.0
8/8 7.6 2.0 .30 2.5 3.5 18 28 <2.0
8/15 9.2 4.8 .40 2.6 20 1.0 <2.0
8/22 9.2 2.5 .20 1.2 190 77 <2.0
8/29 8.9 2.4 .30 3.6 10 19 45 <2.0
9/5 9.4 28.0 3.5 .35 3.2 2.5 39 18 <2.0
9/12 9.1 2.6 2.5 11 jo <2.0
9/19 9.3 25.0 3.3 .40 2.4 1.0 41 30 <2.0
9/26 9.3 22.0 1.5 .30 2.2 2.0 14 17 <2.0
10/3 9.4 20.0 2.5 .30 2.2 16 36 <2.0
10/10 9.7 18.0 1.7 .25 4.0 4.5 5.5 6.0 <2.0
10/17 9.6 15.5 1.4 .30 2.8 7.0 8.5 7.5 <2.0
10/29 9.5 16.5 2.6 .20 3.6 2.5 7.5 11 <2.0
10/31 7.9 15.0 .85 2.0 3.0 1.0 1.0 1.0 <2.0
11/7 7.9 17.5 .72 .35 .55 2.0 3.0 3.5 <2.0
11/14 9.4 12.5 1.4 .25 2.2 4.5 10 9.S <2.0
11/28 9.0 9.5 .59 .15 2.6 1.0 3.0 8.0 <2.0
12/5 9.4 9.0 1.1 .25 2.2 3.5 8.0 11 <2.0
12/12 9.2 6.5 .71 .50 2.0 10 5.0 9.0 <2.0
12/19 8.8 7.5 1.3 .25 2.4 5.0 15 8.0 2.0
1/2/18 9.3 6.0 .68 .55 2.2 8.0 9.5 3.5 <2.0
1/9 9.3 6.0 1.1 .30 2.8 7.5 12 1.0 <2.0
1/23 8.8 5.0 .69 .20 2.8 3.5 4.5 4.5 <2.0
1/30 9.4 5.0 1.0 .55 3.2 7.5 7.0 75 <2.0
2/13 9.3 4.5 1.2 .25 2.8 1.0 1.5 4.0 2.0
2/20 9.1 4.0 .84 .50 3.2 3.5 3.0 5.0 <2.0
2/27 9.1 5.0 .67 .55 2.8 4.5 5.5 6.5 <2.0
3/6 9.0 4.0 .78 .10 2.8 2.5 4.0 4.0 <2.0
3/13 8.0 6.0 1.3 .70 1.0 7.5 7.5 1.5 <2.0
1/20 9.1 7.5 1.2 .40 2.6 6.5 9.0 8.0 2.0
3/27 8.3 8.5 1.1 .25 2.2 2.0 5.0 12 <2.0
4/3 8.1 10.5 .99 .15 2.0 4.5 4.5 4.0 <2.0
4/10 9.2 15.0 1. .1 .55 2.4 4.0 6.0 5.5 2.0
1.6 .39 2.5 15 15
std. d. . 1.0 .33 .72 32 18
144
-------
TABLE D--4.
BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 4 - FREDERICK
Te η.
Turbidity
free
Cl
lotal Cl
Plate
Count
Plate
Count
Plate
Count
coliform
Week of pH C
NTU
mg/i
mg/i
48
hr.
35C
96
hr.
35C
9
day
20C
MPN/iOO ml
7/25/77
8.5
2.0
180
280
310
<2.0
8/1
8.6
3.0
.40
160
380
310
<2.0
8/8
8.3
-
1.7
.20
2.0
190
370
350
<2.0
8/15
8.9
1.6
.40
1.4
240
170
<2.0
8/22
9.2
1.5
.20
2.4
60
71
<2.0
8/29
8.4
1.8
.20
2.4
170
160
<2.0
9/5
9.6
26.0
1.4
.30
2.4
28
120
86
<2.0
9/12
8.7
1.4
10
280
320
<2.0
9/19
8.7
25.0
1.0
.05
1.1
12
190
280
<2.0
9/26
9.0
24.0
1.2
.15
1.4
430
1000
<2.0
10/3
9.5
22.5
1.4
.25
2.2
73
78
<2.0
10/10
9.6
19.5
1.3
.70
3.0
35
310
210
<2.0
10/17
9.3
17.0
1.5
.80
1.4
1.0
150
510
<2.0
10/24
9.5
17.0
1.2
.40
2.4
45
100
79
<2.0
10/31
9.1
17.0
1.5
.30
3.0
110
180
190
<2.0
11/7
9.0
17.0
1.3
.20
1.5
210
820
1300
(2.0
11/14
9.5
15.0
1.3
.20
1.6
260
980
970
<2.0
11/28
8.5
11.0
.71
.15
L8
110
290
280
<2.0
12/5
12/12
9.3
9.3
10.5
8.0
1.1
1.1
.15
.20
2.4
1.8
38
53
130
130
150
140
<2.0
2.0
12/19
7.9
8.0
1.5
.15
1.2
32
320
260
2.0
1/2/78
9.3
6.5
1.4
.20
2.4
18
170
170
<2.0
1/9
9.3
7.0
2.5
.20
2.0
8.5
160
250
<2.0
1/23
9.3
5.5
1.3
.20
2.0
3.0
120
83
(2.0
1/30
9.4
5.5
1.1
.25
3.0
5.5
100
86
<2.0
2/13
9.1
5.0
2.1
.25
2.4
3.0
22
9.5
<2.0
2/20
9.0
5.5
1.0
.20
1.8
6.5
380
370
<2.0
2/27
8.4
5.0
1.1
.25
3.0
16
130
120
<2.0
3/6
9.0
4.0
.86
.10
2.0
2.0
33
20
<2.0
3/13
8.1
5.5
4.6
.10
2.4
7.5
16
13
<2.0
3/20
9.0
6.0
1.5
.15
1.8
4.0
32
25
7.0
3/27
8.2
9.0
2.4
.05
2.0
4.5
62
120
2.0
4/3
8.1
10.0
1.6
.15
2.0
8.0
190
190
<2.0
4/10
7.9
12.0
2.1
0
1.4
1.5
40
36
<2.0
mean
1.6
.23
2.1
219
256
std. dcv.
.72
.16
.54
208
292
145
-------
TABLE D5. BIOLOGICAL, CHEMICAL, ANI) PHYSICAL DATA, STATION 23 -
BALT IMORE
Temp.
Turbidity
free
Ci
Plate
Count
Plate
Count
Plate
Count
coiiform
Week of pH C
NT IJ
mg/i
48
hr.
35 C
96
hr.
35CC
9
day
20C
MPN/100
ml
7/18/77 7.6 17.2 .40 .30 <1.0 1.0 <1.0 <2.0
1/25 7.6 17.8 .46 .80 <1.0 <1.0 <2.0
8/1 7.5 17.8 .81 1.0 <1.0 <1.0 <1.0 <2.0
8/8 CLOSED
8/15 7.S 17.8 1.1 .80 3.0 <1.0 <2.0
8/22 7.2 17.8 .35 .90 1.0 1.0 <2.0
8/29 7.6 17.8 .33 1.0 1.0 1.0 <1.0 <2.0
9/5 7.2 17.8 .40 1.0 <1.0 1.0 <1.0 <2.0
9/12 7.4 17.8 .48 1.0 1.0 1.0 <1.0 <2.0
9/19 CLOSED
9/26 7.2 17.8 .38 .80 <3.0 1.0 1.0 <2.0
10/3 7.4 16.1 .36 .80 <1.0 <1.0 <2.0
10/10 7.3 15.6 .41 .90
-------
TABLE D6. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 27
BALT IMORE
Temp Turbidity free Cl Plate Count Plate Count Plate Count coliforn
Week of pfl C NTU mo/ i 48 hr. 35°C 96 hr. 35°C 9 day 20°C MPN/100 ol
7/18/77 7.4 22.8 .30 0 3.0 45 980 <2.0
7/25 7.4 24.4 .44 0 1.5 14 680 <2.0
8/1 7.4 24.4 .74 0 10 53 380 <2.0
8/8 7.4 24.4 1.1 0 3.0 24 770 <2.0
8/15 7.2 24.4 .76 0 12 1100 <2.0
8/22 7.2 24.4 .91 0 4.5 590 <2.0
8/29 7.5 23.3 .47 0 1.0 1.5 310 <2.0
9/5 7.4 23.3 .30 0 2.0 3.0 340 <2.0
9/12 7.4 23.3 .40 0 3.0 5.0 140 <2.0
9/19 7.6 22.8 .28 0 4.0 8.5 26 <2.0
9/26 7.4 23.7 .32 0 7.5 9.0 49 <2.0
10/3 7.4 20.0 .34 0 - 9.5 48 <2.0
10/10 7.3 18.3 .34 0 5.5 8.5 40 <2.0
10/17 7.4 17.8 .36 0 <1.0 2.0 86 <2.0
10/24 7.4 16.1 .35 0 1.5 15 75 <2.0
10/31 7.5 16.7 .47 12 14 330 <2.0
11/7 7.4 16.1 .60 0 1.0 4.5 460 <2.0
11/14 7.6 15.0 .44 0 <1.0 14 110 <2.0
11/28 7.7 13.9 .46 0 5.0 14 1000 <2.0
12/5 7.4 12.2 .51 0 <1.0 11 620 <2.3
12/12 7.4 9.4 .63 .10 1.0 1.5 1300 <2.0
12/19 7.3 8.3 .50 .30 1.0 1.0 53 <2.0
1/2/78 7.2 7.8 1.0 .20 <1.0 1.0 6000 <2.0
1/9 7.3 5.6 .86 .30 <1.0 <1.0 120 <2.0
1/23 7.2 3.9 .64 .05 <1.0 <1.0 4.0 <2.0
1/30 7.2 4.4 .75 .30 1.0 1.0 440 <2.0
2/13 8.2 3.9 1.0 .30 <1.0 1.0 35 <2.0
2/20 7.2 3.9 .76 .20 <1.0 <1.0 280 <2.0
2/27 7.1 3.9 .75 .15 <1.0 1.0 1.0 <2.0
3/6 7.2 4.4 .85 .20 <1.0 1.0 28 <2.0
3/13 7.0 4.4 .82 .15 <1.0 1.5 320 <2.0
3/20 7.2 6.7 .92 0 1.0 1.0 410 <2.0
3/27 7.2 7.2 .78 .10 <1.0 <1.0 570 <2.0
4/3 7.2 7.9 1.1 0 <1.0 1.0 2000 <2.0
4/10 7.4 10.0 .99 .10 - - <2.0
4/17 7.2 11.1 1.0 .30 9.0 16 20 <2.0
4/24 CLOSED
5/1 7.2 14.4 .68 0 26 <2.0
5/8 7.2 13.3 .48 0 16 4500 <2.0
5/22 7.2 14.4 .50 0 16 2600 <2.0
5/29 7.2 16.7 .39 0 78 1700 <2.0
mean .63 .07 11 750
std. dev. .25 .11 1239
147
-------
TABLE D-7. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 28 -
BALT INORE
Temp. Turbithty free Cl Plate Count Plate Count Plate Count coliforn
Week of pH C NTU mg/i 48 hr. 35C 96 hr. 35C 9 day 20CC MPN/l00 ml
7/18/77 7.6 23.3 .33 .45 1.0 2.5 2.5 <2.0
7/25 7.5 24.4 .41 .30 <1.0 1.0 3.5 <2.0
8/1 7.5 21.7 .80 .45 3.5 9.5 15 <2.0
8/8 7.4 2c.6 .87 .45 <1.0 <1.0 3.0 <2.0
8/15 7.3 24.4 1.3 .30 7.5 9.0 <2.0
8/22 7.4 24.4 .35 .20
-------
TABLE D8. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 29
BALTIMORE
Temp. Turbidity free C i Plate Count Plate Count Plate Count coliforn
Week of pH C NTU eq/i 48 hr. 35CC 96 hr. 35 C 9 day 20CC MPN/i00 ml
7/18/77 7.4 21.7 .44 .30 84 88 80 <2.0
7/25 7.4 21.1 .51 .30 30 32 30 <2.0
8/1 7.4 21.1 1.2 .30 4.5 6.0 19 <2.0
8/8 7.3 21.1 1.1 .45 72 81 76 <2.0
8/15 7.4 21.1 1.3 .30 20 16 <2.0
8/22 7.2 23.3 .34 .05 3.5 6.0 <2.0
8/29 7.6 22.2 .41 .30 35 40 35 <2.0
9/5 7.4 22.2 .46 .80 39 100 98 <2.0
9/12 7.4 22.8 .35 0 14 17 29 <2.0
9/19 7.6 23.3 .28 .20 8.0 18 8.0 <2.0
9/26 7.4 21.1 .37 .20 11 12 18 <2.0
10/3 7.6 20.0 .44 .20 25 28 <2.0
10/10 7.4 19.4 .36 .45 15 29 20 <2.0
10/17 7.4 17.8 .44 .30 3.0 6.0 9.5 <2.0
10/24 7.4 17.8 .47 .45 40 57 58 <2.0
10/31 7.6 20.0 .55 .20 120 130 130 <2.0
11/7 7.4 16.7 .72 .80 34 29 35 <2.0
11/14 7.4 16.7 .56 .45 7.0 9.5 26 <2.0
11/28 7.7 14.4 .71 .45 28 41 44 <2.0
12/5 7.2 12.2 .56 .55 29 33 44 <2.0
12/12 7.2 11.1 .36 .45 2.0 7.0 13 <2.0
12/19 7.2 10.0 .6]. .80 4.5 9.5 12 <2.0
1/2/78 7.2 10.6 .55 .45 1.5 5.5 14 <2.0
1/9 7.3 7.2 .67 .60 1.0 3.5 6.0 <2.0
1/23 7.2 4.4 .52 .45 4.0 8.5 ii <2.0
1/30 7.2 4.4 .94 .55 19 25 19 <2.0
2/13 7.6 3.9 .76 .55 7.5 11 12 <2.0
2/20 7.0 3.3 .81 .55 6.0 9.0 8.0 <2.0
2/27 7.0 5.6 .72 .20 9.0 12 19 <2.0
3/6 7.0 5.6 .79 .30 8.0 9.5 23 <2.0
3/13 7.0 5.6 .50 .45 28 33 37 <2.0
3/20 7.0 6.7 .86 .45 11 12 15 <2.0
3/27 7.2 7.8 .69 .30 54 63 64 <2.0
4/3 7.2 7.8 .90 .45 16 19 6.0 <2.0
4/10 7.1 10.0 1.0 .30 - - <2.0
4/17 7.3 11.1 1.1 0 <1.0 7.0 1800 <2.0
4/24 7.1 13.9 .55 .20 27 67 <2.0
5/ 1 7.2 14.4 .47 .20 1.0 <2.0
5/8 7.2 12.2 .45 .45 17 39 <2.0
5/22 7.4 15.6 .38 .30 69 180 <2.0
5/29 7.4 15.6 .42 .30 110 160 <2.0
mean .62 .37 31 85
stci. dev. .26 32 285
149
-------
TABLE D-9. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 30
BALT INORE
Temp. Turbidity free Cl Plate Count Plate Count Plate Count coiiform
Week of p14 C WTTJ mg/i 48 hr. 35CC 96 hr. 35CC 9 day 20 C 1498/100 ml
7/18/78 7.3 21.7 .60 .05 <1.0 3.0 3.5 <2.0
7/25 7.4 21.7 .30 .05 <1.0 2.0 1.0 <2.0
8/1 7.4 22.2 1.1 .45 <1.0 1.5 1.0 <2.0
8/8 7.3 23.3 1.0 .10 1.0 1.0 1.0 <2.0
8/15 7.4 23.3 .75 .20 <1.0 1.0 <2.0
8/22 7.2 23.3 .41 .30 <1.0 1.0 <2.0
8/29 7.5 22.8 .38 .15 1.5 1.5 1.0 <2.0
9/5 7.4 22.2 .36 .30 <1.0 <1.0 <1.0 <2.0
9/12 7.6 22.2 .40 .10 1.5 2.0 3.0 <2.0
9/19 7.6 21.1 .28 .30 15 16 17 <2.0
9/26 7.4 20.0 .35 .20 1.5 2.5 <1.0 <2.0
10/3 7.6 18.9 .46 .30 19 4.0 <2.0
10/10 7.3 16.7 .43 .30 <1.0 1.0 <1.0 <2.0
10/17 7.4 15.0 .48 .55 <1.0 1.5 <1.0 <2.0
10/24 7.4 14.4 .40 .10 1.0 3.5 1.5 <2.0
10/31 7.3 19.4 .46 .30 1.0 3.5 1.0 <2.0
11/7 1.3 16.1 .50 .55 1.5 4.0 <1.0 <2.0
11/14 7.4 13.3 .56 .80 <1.0 5.0 1.0 <2.0
11/28 1.5 10.6 .60 .80 1.0 1.0 32 <2.0
12/5 7.2 10.0 .42 .80 <1.0 1.0 1.5 <2.0
12/12 7.3 7.8 .34 .55 1.0 1.0 1.0 <2.0
12/29 7.2 7.2 .59 .80 <1.0 <1.0 2.0 2.0
1/2/78 7.2 5.0 .58 .55 1.0 1.5 <1.0 <2.0
1/9 7.1 5.6 .75 .55 1.0 1.0 2.5 <2.0
1/23 7.0 2.8 .45 .55 <1.0 <1.0 2.5 <2.0
1/30 7.1 3.3 .69 .80 <1.0 1.0 <1.0 <2.0
2/13 7.0 2.2 .99 .30 1.0 1.0 <1.0 <2.0
2/20 7.0 2.2 .59 .80 <1.0 <1.0 <1.0 <2.0
2/27 7.2 3.3 .65 .80 <1.0 1.0 1.5 <2.0
3/6 7.0 3.3 .62 .55 <1.0 <1.0 4.0 <2.0
3/13 7.2 4.4 .56 .55 <1.0 <1.0 1.0 <2.0
3/20 7.0 6.1 .74 .30 <1.0 1.0 2.0 <2.0
3/27 7.0 6.7 .69 .55 34 45 40 <2.0
4/3 7.2 7.8 .92 .30 <1.0 4.5 1.0 <2.0
4/10 7.2 10.0 .91 .30 <2.0
4/17 7.2 12.2 .74 .45 1.0 3.5 4.0 <2.0
4/24 1.2 12.2 .46 .30 8.5 5.5 <2.0
5/1 7.4 12.2 .45 .20 33 <2.0
5/8 7.1 12.2 .40 .45 13 13 <2.0
5/22 7.2 16.1 .30 .45 73 100 <2.0
5/29 7.2 16.7 .35 .20 22 46 <2.0
mean .56 .41 7.0 7.6
aId. dev. .21 .23 14 19
150
-------
TABLE D1O. BIOLOGICAL, CHEMICAL, AND VHYSICAL DATA, STATION 31 -
BALT INORE
temp. turbidity free Cl Plate Count Plate Count Plate Count coliform
Week of pH C NTLJ mg/i 48 hr. 35 C 96 hr. 35CC 9 day 20CC MPN/l00 tnt
7/18/78 7.4 23.3 .40 0 1.0 11 1200 <2.0
7/25 7.4 21.1 .40 0 <1.0 9.0 530 <2.0
8/1 7.3 23.3 1.4 0 1.5 4.5 290 <2.0
8/8 7.4 24.4 1.0 0 1.0 8.0 150 <2.0
8/15 7.2 23.9 1.5 0 14 240 <2.0
8/22 7.4 23.3 .61 0 20 230 <2.0
8/29 7.4 23.3 .41 0 1.5 8.5 310 <2.0
9/5 7.4 23.3 .35 .20 2.0 12 130 <2.0
9/12 7.2 23.3 .38 0 1.5 28 290 <2.0
9/19 7.6 22.2 .45 0 1.5 32 350 <2.0
9/26 7.2 22.2 .51 .05 530 850 <2.0
10/3 7.3 20.6 .78 0 1300 1800 <2.0
10/10 7.4 18.9 .40 0 1.0 1.0 94 <2.0
10/17 7.6 17.2 .71 0 <1.0 12 2600 <2.0
10/24 7.4 16.1 .45 .10 1.0 19 840 <2.0
10/31 7.4 18.9 .56 0 12 41 370 <2.0
11/7 7.4 16.1 1.0 0 <1.0 14 550 <2.0
11/14 7.6 14.4 .58 0 5.5 110 <2.0
11/28 7.7 13.3 .71 0 <1.0 30 1700 <2.0
12/5 7.4 11.1 .44 .15 <1.0 3.5 660 <2.0
12/12 7.3 10.0 .59 .10 1.0 20 2000 <2.0
12/19 7.4 8.9 .73 .30 <1.0 1.0 150 <2.0
1/2/78 7.2 7.8 .86 0 1.5 17 1700 <2.0
1/9 CLOSED
1/23 7.2 3.9 .78 .20 <1.0 1.5 46 <2.0
1/30 7.1 3.9 .85 .25 <1.0 1.0 99 <2.0
2/13 7.6 3.9 .95 .20 1.0 2.0 98 <2.0
2/20 7.2 3.9 .85 .30 <1.0 1.0 160 <2.0
2/27 7.0 3.3 .91 .20 1.5 2.5 150 <2.0
3/6 7.1 3.9 .85 .30 <1.0 <1.0 78 <2.0
3/13 7.2 6.7 .79 .30 <1.0 <1.0 17 <2.0
3/20 7.2 6.7 .85 .05 3.5 4.0 120 <2.0
3/27 7.2 7.2 .69 .20 <1.0 3.5 77 <2.0
4/3 7.6 8.3 .98 .20 <1.0 2.0 6.2 <2.0
4/10 7.4 11.1 1.1 .20 <2.0
4/17 7.3 11.1 1.3 0 6.5 27 3400 <2.0
4/24 7.2 12.2 .75 0 2.5 930 <2.0
5/1 7.2 11.7 1.1 0 32 1200 <2.0
5/8 7.2 12.2 .55 0 10 840 <2.0
5/22 7.4 17.8 .46 0 8.0 1700 <2.0
5/29 7.2 16.1 1.2 0 1300 -- <2.0
mean .75 .08 93 701
std. dey. .29 .11 296 811
151
-------
TABLE D-11. B1QLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 34 -
BALTIMORE
Temp. Turbidity free Cl Plate Count Plate Count Plate Count coliform
Week of pH C NTU mg/i 48 hr. 35C 96 hr. 35C 9 day 20C MPN/100 ci.
7/18/77 7.3 26.1 .50 .30 16 23 40 2.0
7/25 7.3 27.8 .58 .10 7.0 24 53 <2.0
8/1 7.3 20.0 1.2 .80 <1.0 <1.0 <1.0 <2.0
8/8 7.3 25.6 .70 .05 <1.0 31 40 <2.0
8/15 7.4 26.7 .55 .30 4.0 7.0 <2.0
8/22 7.4 25.0 .45 .45 9.0 15 <2.0
8/29 7.4 26.7 .30 .05 <1.0 5.0 40 <2.0
9/5 7.6 24.4 .41 .70 <1.0 5.0 25 <2.0
9/12 7.4 25.0 .40 .15 1.0 1.5 6.0 2.0
9/19 7.6 24.4 .30 .30 1.0 1.0 6.5 <2.0
9/26 7.2 22.2 .36 .45 11 23 47 <2.0
10/3 7.4 22.2 .40 .20 4.5 4.5 <2.0
10/10 7.3 20.0 .44 .20 <1.0 1.5 12 2.0
10/17 7.4 18.9 .53 .45 <1.0 8.5 16 <2.0
10/24 7.4 18.9 .41 0 1.0 15 16 2.0
10/31 7.3 18.9 .46 .15 7.5 270 99 <2.0
11/7 7.4 16.7 .61 .30 7.5 37 140 2.0
11/14 1.4 13.3 .68 .30 10 46 310 <2.0
11/28 7.7 12.2 .69 .30 380 2300 <2.0
12/5 7.3 12.2 .50 .20 <1.0 6.0 6.5 <2.0
12/12 7.3 8.9 .48 .55 1.0 4.5 <2.0
12/19 7.2 8.9 .58 .55 11 32 54 <2.0
1/2/78 7.3 6.7 1.1 .20 11 20 37 <2.0
1/9 7.3 6.7 .91 .30 7.5 25 28 <2.0
1/23 7.2 3.9 2.4 .55 21 380 1300 <2.0
1/30 7.2 3.3 .79 .30 1100 1000 <2.0
2/13 7.0 3.9 1.2 .15 7.5 260 190 <2.0
2/20 7.0 3.9 .87 .30 2.0 2.5 1.0 <2.0
2/27 7.2 3.9 1.0 .55 2.0 12 7.0 2.0
3/6 7.2 3.3 .71 .45 <1.0 1.5 2.5 2.0
3/13 7.0 5.0 .60 .55 2.5 25 44 2.0
3/20 7.2 5.6 .98 .30 5.5 1 76 <2.0
3/27 7.2 6.7 1.1 .55 10 140 160 <2.0
4/3 7.4 7.8 1.0 .20 1.0 25 39 <2.0
4/10 7.4 11.1 1.2 .05 - <2.0
4/17 7.2 13.3 1.2 .30 1.0 5.0 17 <2.0
4/24 7.0 13.3 .85 .20 100 1500 (2.0
S/i 7.2 13.3 .99 0 15 5500 2.0
5/8 7.2 13.3 .57 .20 42 2.0
5/22 7.2 14.4 .45 .05 15 120 <2.0
5/29 16.7 1.1 .15 60 460 2.0
emn .74 107 344
std. d c v. .39 .19 253 963
152
-------
TABLE D12. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 35 -
BALTIMORE
Temp. Turbidity free Cl Plate Count Plate Count Plate Count coliforn
Week of pH C NTU mg/i 48 hr. 35C 96 hr. 35C 9 day 20CC MPN/100 ni
7/18/77 7.2 20.6 .30 .15 1.0 2.0 5.5 <2.0
7/25 7.4 20.6 .42 .20 2.5 19 25 <2.0
8/1 7.4 20.6 1.0 .20 <1.0 12 <1.0 <2.0
8/8 7.2 21.1 .91 .05 1.0 10 1.0 <2.0
8/15 7.2 21.1. .60 .55 1.5 1.0 <2.0
8/22 7.2 20.6 .75 .55 1.0 <1.0 <2.0
8/29 7.4 20.6 .51 .10 <1.0 1.0 <1.0 <2.0
9/5 7.2 21.7 .49 .55 3.0 13 <1.0 <2.0
9/12 7.2 20.6 .36 .05 <1.0 1.0 <1.0 2.0
9/19 7.4 20.0 .36 .05 1.0 1.0 2.0 <2.0
9/26 7.4 20.0 .41 .80 1.0 <1.0 <1.0 <2.0
10/3 7.4 18.3 .55 .05 2.0 2.5 <2.0
10/10 7.3 16.7 .36 .10 <1.0 1.0 11 <2.0
10/17 7.4 17.8 .42 1.0 <1.0 <1.0 <1.0 <2.0
10/24 7.4 13.3 .53 .90 1.0 1.0 <1.0 <2.0
10/31 7.3 17.8 .58 .20 <1.0 17 38 <2.0
11/7 7.4 15.6 .43 .80 <1.0 <1.0 3.5 <2.0
11/14 7.4 13.3 .91 0 <1.0 5.5 56 <2.0
11/28 7.7 10.6 .46 1.0 <1.0 <1.0 1.0 <2.0
12/5 7.5 10.0 .75 .20 3.0 52 220 <2.0
12/1.2 7.2 7.8 .46 .30 <1.0 <1.0 2.5 <2.0
12/19 7.3 7.8 .60 .45 <1.0 1.5 2.0 <2.0
1/2/78 7.3 8.9 .66 .30 <1.0 14 29 <2.0
1/9 7.2 5.0 .62 .20 1.0 2.0 3.5 <2.0
5/23 7.1 3.9 .77 .30 <1.0 <1.0 <1.0 <2.0
1/30 7.2 3.3 .76 .45 <1.0 1.0 1.0 <2.0
2/13 7.0 3.3 .98 .20 <1.0 1.0 1.0 <2.0
2/20 7.0 3.3 .82 .30 <1.0 <1.0 3.5 <2.0
2/27 7.2 3.3 .98 .30 <1.0 4.0 1.0 <2.0
3/6 7.2 3.9 .80 0 <1.0 1.0 2.9 <2.0
3/13 7.0 3.9 .98 .20 <1.0 <1.0 4.5 <2.0
3/20 7.4 5.6 .74 .30 <1.0 1.0 3.0 <2.0
3/27 7.2 5.6 .95 .30 <1.0 1.0 8.0 <2.0
4/3 7.2 8.3 1.0 .15 <1.0 1.0 9.5 <2.0
4/10 7.3 10.0 .96 0 -- <2.0
4/17 7.2 12.2 .94 0 1.0 52 120 <2.0
4/24 7.0 12.2 .85 .10 1.0 350 <2.0
5/1 7.2 12.2 .62 0 470 <2.0
5/8 7.2 12.2 .62 .05 1.0 56 <2.0
/22 7.2 14.4 .77 .10 12 370 <2.0
5/29 7.4 1.6.7 .62 0 45 170 <2.0
mean .67 .28 19 39
std. deC. .22 .28 74 89
153
-------
TABLE D13. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 36
BALTIMORE
Temp. Turbidity free Cl Plate Count Plate Count Plate Count coliform
week of pH
-------
TABLE D14. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 37 -
BALTIMORE
Temp. Turbidity free Cl Plate Count Plate Count Plate Count coliform
Week of pH C NTV mg/i 48 hr. 35C 96 hr. 35CC 9 day 20CC MPN/lO0 ml
7/18/77 7.3 30.0 1.8 0 55 290 280 <2.0
7/25 7.4 26.7 2.5 0 880 1100 1100 <2.0
8/1 CLOSED
8/8 7.4 29.4 7.1 0 380 780 1600 <2.0
8/15 7.4 26.7 5.1 0 4900 6600 <2.0
8/22 7.8 27.2 7.1 0 590 560 <2.0
8/29 7.5 30.0 7.6 0 440 550 <2.0
9/5 7.6 27.2 8.4 0 150 560 650 <2.0
9/12 7.4 26.1 .85 0 1100 970 <2.0
9/19 7.5 27.2 1.i 0 75 420 500 <2.0
9/26 7.2 26.7 2.3 0 130 360 <2.0
10/3 7.4 24.4 1.4 0 260 520 <2.0
10/10 7.3 20.0 1.1 0 1.0 12 300 <2.0
10/17 7.4 21.7 1.2 0 210 310 <2.0
10/24 7.4 20.0 1.1 0 20 340 1400 <2.0
10/31 7.3 26.0 1.3 0 840 2300 <2.0
11/7 7.2 18.9 1.3 0 260 1700 <2.0
11/14 7.4 14.4 0.65 .45 <1.0 7.5 19 <2.0
11/28 7.7 18.9 1.6 .10 76 550 9500 <2.0
12/5 7.6 18.3 0.91 0 75 300 4000 <2.0
12/12 7.3 17.8 2.1 0 21 310 8800 <2.0
12/19 7.4 11.7 1.3 0 5.5 100 1400 <2.0
1/2/78 7.3 5.6 .81 .20 1.0 5.5 8.5 <2.0
1/9 7.2 7.2 1.2 .20 2.0 3.0 680 <2.0
1/23 7.1 5.6 .65 0 10 36 49 <2.0
1/30 7.2 4.4 2.6 0 2.5 320 2000 <2.0
2/13 7.2 8.9 2.1 0 14 400 1700 <2.0
2/20 7.2 15.6 1.9 0 7.5 24 2700 <2.0
2/27 7.3 11.1 .74 0 8.5 520 1300 <2.0
3/6 7.0 8.9 .85 0 3.0 88 720 <2.0
3/13 7.0 12.2 1.3 0 50 400 1900 <2.0
3/20 7.2 15.6 3.0 0 22 1100 4000 <2.0
3/27 CLOSED
4/3 7.3 14.4 3.1 0 31 460 1900 <2.0
4/10 7.2 12.2 1.4 0 <2.0
4/17 7.2 12.2 .96 .45 1.0 12 37 <2.0
4/24 7.0 15.6 2.3 0 300 3100 <2.0
5/1 CLOSED
5/8 7.2 17.2 1.7 0 670 4100 <2.0
5/22 7.2 21.1 2.9 0 1300 7500 <2.0
5/29 CLOSED
mean 2.3 .04 531 2086
std. dev. 2.1 .11 825 2461
155
-------
TABLE D15. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 38
BALTIMORE
Teap. Turbidity free Cl Plate Count Plate Count Plate Count Ooliform
Weak of pM c !r*/1 48 hr. 35C 66 hr. 35CC 9 day 20 C MPN/100 ml
7/18/77 7.4 16.7 .80 <1.0
-------
TABLE D16. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 42
BALT IMORE
Tetnp. Turbidity free Ci Plate Count Plate Count Plate Count coliform
Week of pH C NT(J mg/i 48 hr. 35C 96 hr. 35C 9 day 20 C MPH/tOO m l
7/18/71 7.2 21.1 .33 .80 1.0 12 1.0 <2.0
7/25 7.3 21.1 .51 .80 1.5 14 8.0 <2.0
8/1 CLOSED
8/8 7.2 21.1 .80 .30 1.0 11 5.0 <2.0
8/15 7.2 23.3 .40 .55 8.5 4.5 <2.0
8/22 7.4 22.2 .35 .55 2.0 1.0 1.0 <2.0
8/29 7.2 22.2 .29 .30 1.0 2.0 <1.0 <2.0
9/5 7.4 21.7 .33 .45 2.0 4.5 <2.0
9/12 7.2 20.6 .32 .45 3.5 6.0 2.5 <2.0
9/19 7.3 22.2 .46 .55 20 27 <2.0
9/26 7.2 22.2 .29 .30 <1.0 3.5 3.0 <2.0
10/3 7.3 20.0 .50 .55 1.0 1.0 2.0 <2.0
10/10 7.5 20.0 .31 .55 <1.0 <1.0 1.0 <2.0
10/17 7.2 15.0 .73 .45 <1.0 1.0 1.0 <2.0
10/24 7.4 15.6 .58 .55 1.0 19 5.0 <2.0
10/31 7.4 11.8 .54 .30 1.0 2.0 33 <2.0
11/7 7.2 15.6 .63 .55 2.5 8.0 33 <2.0
11/14 7.4 13.3 .48 .45 3.0 7.0 24 <2.0
11/28 7.2 11.1 .60 .55 1.5 1.5 26 <2.0
12/5 7.4 9.4 .75 .80 <1.0 <1,0 2.0 <2.0
12/12 7.3 8.3 .61 .55 <1.0 1.0 1.5 <2.0
12/19 7.6 8.3 .66 .55 1.0 1.5 2.0 <2.0
1/2/78 8.1 5.6 .96 .55 1.0 2.0 5.0 <2.0
1/9 7.4 3.3 .74 .55 <1.0 <1.0 3.0 <2.0
1/23 7.5 3.3 .82 .55 9.0 42 440 <2.0
1/30 7.4 3.3 1.0 .80 5.5 6.0 5.0 <2.0
2/13 7.4 3.3 1.2 .55 1.0 3.5 6.0 <2.0
2/20 7.2 3.3 .96 .30 <1.0 <1.0 1.0 <2.0
2/27 7.6 3.9 .94 .55 2.0 2.5 4.0 <2.0
3/6 7.4 3.3 .76 .55 1.0 1.0 1.0 <2.0
3/13 7.2 5.6 .87 .55 <1.0 1.0 2.5 <2.0
3/20 7.8 6.7 .91 .55 <1.0 3.5 <1.0 <2.0
3/27 7.4 6.7 1.0 .50 1.0 2.0 10 <2.0
4/3 7.2 7.8 1.0 .55 <1.0 <1.0 2.5 2.0
4/10 7.3 10.0 .94 .20 <1.0 <1.0 7.0 <2.0
4/17 7.4 12.2 .53 .30 22 28 91 <2.0
4/24 1.3 12.2 .60 .55 2.0 13 <2.0
5/1 CLOSED
5/8 7.4 12.2 .43 .80 6.0 77 <2.0
5/22 7.4 16.7 .35 .30 6.0 99 <2.0
5/29 7.? 16.7 .49 .30 5.5 41 <2.0
mean 64 26
std. dcv. .25 .16 9.5 73
157
-------
TABLE D-17. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 43
BALT INORE
Temp. Turbidity free Cl Plate Count Plato Count Plate Count coliforin
Week of pH C NTU ng/l 48 hr. 35C 96 hr. 35°C 9 day 20°C MPN/100 ml
7/18/77 7.2 21.1 .33 .80 1.0 12 1.0 <2.0
7/25 7.2 21.1 .60 .80 28 31 37 6.0
8/1 7.2 24.4 .96 .55 32 28 92 <2.0
8/8 7.3 25.6 .60 .15 17 61 390 <2.0
8/15 7.2 23.2 .61 .20 1.5 47 <2.0
8/22 7.2 23.9 .45 .20 1.0 5.5 29 <2.0
8/29 7.4 23.3 .46 .20 5.0 7.0 6.5 <2.0
9/5 7.2 23.9 .29 .20 14 17 28 <2.0
9/12 7.2 24.4 .25 .20 4.0 5.5 5.0 <2.0
9/19 7.3 22.2 .45 .45 10 <1.0 <2.0
9/26 7.2 22.2 .30 .30 9.0 16 13 <2.0
10/3 7.3 21.1 .38 .20 4.0 4.0 3.5 <2.0
10/ 10 7.2 20.0 .32 .45 7.5 9.0 12 <2.0
10/17 7.4 17.8 .95 .30 1.0 1.0 <1.0 <2.0
10/24 7.2 15.6 .36 .45 2.5 2.5 2.0 <20
10/31 7.4 16.1 .33 .20 5.0 5.0 5.0 <2.0
11/7 7.4 16.1 .36 .45 1.0 1.0 7.5 <2.0
11/14 7.4 14.4 .45 .55 26 33 41 <2.0
11/28 7.2 13.3 .56 .45 21 21 71 <2.0
12/S 7.4 10.0 .50 .55 <1.0 <1.0 1.0 <2.0
12/12 7.3 8.9 .40 .45 3.0 4.0 5.0 <2.0
12/19 7.4 8.9 1.20 .55 1.5 23 5.0 <2.0
1/2/78 7.8 7.8 .54 .55 1.5 1.5 3.5 <2.0
1/9 7.3 5.6 1.0 .55 6.0 9.0 13 <2.0
1/23 7.4 3.3 .53 .55 1.0 2.0 4.5 <2.0
1/30 7.4 3.9 1.3 .55 13 14 100 <2.0
2/13 7.2 4.4 1.6 .55 5.0 8.5 7.5 <2.0
2/20 7.2 3.9 .79 .45 <1.0 <1.0 3.0 <2.0
2/27 7.2 56 1.0 .55 2.5 4.5 4.0 <2.0
3/6 7.4 3.9 .64 .55 <1.0 1.0 1.0 <2.0
3/13 7.3 6.6 .56 .80 2.5 5.5 2.0 <2.0
3/20 7.2 6.7 .87 .55 1.5 1.5 3.0 <2.0
3/27 7.4 6.1 .61 .40 1.5 2.0 6.0 <2.0
4/3 7.3 8.3 .9S .45 <1.0 1.0 1.0 <2.0
4/10 7.4 11.1 1.0 .45 2.0 2.0 <1.0 <2.0
4/17 7.3 13.9 .68 .55 1.0 2.0 1.5 <2.0
4/24 7.4 14.4 .43 .55 1.0 14 <2.0
5/1 7.2 14.4 .75 .55 1.0 28 <2.0
5/8 7.4 12.2 .39 .55 <1.0 17 <2.0
5/22 7.4 16.1 .29 .45 1.5 89 <2.0
S/29 7.2 18.3 .36 .30 2.5 11 <2.0
mean .62 .45 8.7 27
*td. 8ev. .31 .17 12 64
158
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TABLE D-18. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 44
BALTIMORE
Temp. Turbidity free Cl Plate Count Plate Count Plate Count coliforn
Week of NTLJ mg/i 48 hr. 35CC 96 hr. 35CC 9 day 20CC MPN/100 ml
7/18/77 7.2 21.7 .50 0 3.0 67 210 <2.0
7/25 7.4 21.1 1.5 0 5.5 16 380 <2.0
8/1 7.3 23.3 1.2 0 3.5 54 670 <2.0
8/8 7.5 23.3 .60 0 7.0 63 650 <2.0
8/15 7.4 25.0 1.0 0 61 580 <2.0
8/22 7.4 22.8 .55 0 7.0 26 200 <2.0
8/29 7.4 22.2 .52 0 1.0 9.0 430 <2.0
9/5 7.4 22.2 .33 0 3.5 20 1000 <2.0
9/12 7.4 21.1 .34 0 2.5 13 740 <2.0
9/19 7.3 21.1 1.2 0 3.5 320 <2.0
9/26 7.3 23.3 .70 0 1.0 11 38 <2.0
10/3 7.3 20.0 .54 0 2.5 3.0 160 <2.0
10/10 7.4 20.0 .93 .10 1.0 10 190 <2.0
10/17 7.4 16.7 1.2 0 11 23 190 <2.0
10/24 7.5 15.6 .93 0 4.5 50 260 <2.0
10/31 7.6 15.6 .65 0 3.5 56 670 <2.0
11/7 7.3 16.1 .82 0 4.0 62 1100 <2.0
11/14 7.4 15.0 .81 0 2.0 27 950 <2.0
11/28 7.4 12.8 .56 0 4.5 64 1000 <2.0
12/5 7.8 10.6 .46 .05 1.0 56 320 <2.0
12/12 7.1 10.0 .55 0 3.0 30 390 <2.0
12/19 7.6 9.4 .90 0 1.0 30 180 <2.0
1/2/78 7.9 8.3 1.0 0 2.0 42 1100 <2.0
1/9 7.5 5.6 2.0 0 1.0 19 830 <2.0
1/23 7.4 4.4 1.0 .05 21 84 940 <2.0
1/30 7.2 4.4 1.6 0 11 86 1000 <2.0
2/13 7.4 3.9 1.4 0 6.0 59 270 <2.0
2/20 7.2 3:9 1.1 0 6.5 72 460 <2.0
2/27 7.2 4.4 1.0 0 4.0 57 790 <2.0
3/6 7.4 5.6 .98 0 2.0 35 620 <2.0
3/13 7.4 5.6 .78 0 1.0 40 400 <2.0
3/20 7.8 6.7 1.3 0 <1.0 39 580 <2.0
3/27 7.4 6.1 .90 0 16 270 660 <2.0
4/3 7.4 7.8 1.1 0 8.5 38 970 <2.0
4/1O 7.5 11.1 1.2 0 1.5 23 1200 <2.0
4/17 7.4 12.2 1.3 0 6.0 61 2300 <2.0
4/24 7.7 14.4 .80 0 93 2200 <2.0
5/1 7.4 12.2 .83 0 22 1700 <2.0
5/8 7.6 14.4 .46 0 22 2000 <2.0
5/22 7.4 16.7 .37 0 1400 <2.0
5/29 7.2 17.8 .80 0 84 2400 <2.0
mean .90 .005 48 791
std. dev. .37 .02 44 607
159
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TABLE D19. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 45
BALTIMORE
Temp. Turbidity free Cl Plate Count Plate Count Plate Count coliform
Week of pH C NTU mg/i 48 hr. 35C 96 hr. 35C 9 day 20C MPN/iOO ml
7/18/77 7.2 22.2 .31 .80 1.0 5.0 <1.0 <2.0
7/25 7.2 24.4 .47 1.2 <1.0 1.0 <1.0 <2.0
8/i 7.4 22.2 .53 .80 26 28 25 <2.0
8/8 7.1 23.9 .60 .90 4.0 5.0 <1.0 <2.0
8/15 6.8 23.3 .50 .80 3.0 <2.0
8/22 7.0 23.3 .42 .80 <1.0 1.0 2.0 <2.0
8/29 6.9 23.3 .40 1.0 <1.0 1.0 <1.0 <2.0
9/5 7.1 23.3 .31 1.0 <1.0 <1.0 <2.0
9/12 7.0 22.2 .30 1.2 <1.0 <1.0 <1.0 <2.0
9/19 7.0 23.3 .41 1.0 <1.0 <1.0 <2.0
9/26 7.0 20.6 .30 1.0 <1.0 <1.0 <1.0 <2.0
10/3 7.2 18.9 .42 1.0 <1.0 <1.0 <1.0 <2.0
10/10 7.2 18.3 .35 1.0 <1.0 <1.0 <1.0 <2.0
10/17 7.2 15.6 .60 1.0 <1.0 <1.0 1.0 <2.0
10/24 7.6 15.6 .47 1.0 1.0 1.5 1.0 <2.0
10/31 7.0 16.7 .33 1.2 <1.0 1.0 1.0 <2.0
11/7 7.2 15.0 .38 1.0 <1.0 1.0 <1.0 <2.0
11/14 7.2 15.0 .42 .90 <1.0 1.0 1.5 <2.0
11/28 7.2 9.4 .56 1.0 <1.0 1.0 7.0 <2.0
12/5 7.3 9.4 .63 .55 <1.0 1.0 1.0 <2.0
12/12 7.2 8.9 .65 1.2 3.5 5.5 15 <2.0
12/19 7.3 7.8 .42 1.0 9.5 14 13 2.0
1/2/78 7.6 5.6 .58 1.05 <1.0 <1.0 <1.0 <2.0
1/9 7.2 6.1 .59 1.2 <1.0 <1.0 <1.0 <2.0
1/23 7.2 3.3 .97 .90 1.0 1.5 1.0 <2.0
1/30 7.0 3.3 1.0 1.0 <1.0 <1.0 <1.0 <2.0
2/13 6.8 3.3 1.2 1.2 <1.0 1.0 1.0 <2.0
2/20 7.2 3.3 .93 .80 <1.0 <1.0 <1.0 <2.0
2/27 7.8 3.9 1.0 .80 1.0 1.0 1.0 <2.0
3/6 7.2 3.3 .82 .80 <1.0 1.0 1.0 <2.0
3/13 7.0 4.4 .49 .55 1.5 3.5 62 <2.0
3/20 7.2 6.7 .91 .80 1.0 1.5 <1.0 <2.0
3/27 6.8 6.7 .76 .60 <1.0 <1.0 1.0 <2.0
4/3 7.2 7.8 1.1 .80 2.5 3.0 1.0 2.0
4/10 6.9 11.1 .84 1.2 <1.0 1.0 1.5 <2.0
4/17 7.1 12.2 .69 .80 5.5 1.0 2.0
4/24 6.8 12.2 .57 1.0 1.0 2.0 <2.0
5/1 7.0 13.3 .31 .80 27 67 <2.0
5/8 6.8 12.2 .45 1.0 <1.0 -- <2.0
5/22 7.2 15.0 .29 .55 2.5 3.0 <2.0
5/29 6.8 16.7 1.2 .80 3.5 16 <2.0
.60 .93 2.9 5.7
std. dev. .26 .18 6.3 14.7
160
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TABLE D-20. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 46
BALTIMORE
Temp. Turbidity free Cl Plate Count Plate Count Plate Count coliform
Week of H C mg/i 48 hr. 35C 96 hr. 35C 9 day 20 C MPN/100 ci
7/18/78 7.4 20.0 .45 .80 4.5 5.5 43 <2.0
7/25 7.3 20.6 .71 .80 <1.0 1.0 98 <2.0
8/1 7.3 20.6 1.0 .55 1.5 7.0 7.5 <2.0
8/8 7.1 23.3 .80 .90 11 16 50 <2.0
8/15 7.0 23.3 .55 .80 <1.0 <2.0
8/22 7.2 23.3 .65 .80 1.0 1.0 9.0 <2.0
8/29 7.2 22.2 .42 1.0 1.0 17 15 <2.0
9/5 7.2 21.1 .38 .80 1.0 7.0 48 <2.0
9/12 7.2 22.8 .27 .90 6.0 9.0 9.0 <2.0
9/19 7.2 21.1 .40 1.0 20 39 <2.0
9/26 7.1 21.7 .34 1.0 1.0 2.0 3.0 <2.0
10/3 7.2 20.0 .39 1.0 1.5 2.0 3.0 <2.0
10/10 7.2 18.9 .35 1.0 3.0 2.5 3.5 <2.0
10/17 7.2 15.6 .68 1.0 <1.0 1.0 <1.0 <2.0
10/24 7.4 15.6 .45 1.0 19 32 30 <2.0
10/31 7.3 15.6 .70 .45 3.5 9.5 23 <2.0
11/7 7.3 15.6 .65 .55 <1.0 2.5 21 <2.0
11/14 7.3 13.3 .79 .80 1.5 3.0 12 <2.0
11/28 7.3 12.2 .49 1.2 1.5 3.0 34 <2.0
12/5 7.5 10.6 .61 .25 1.5 6.0 58 <2.0
12/12 7.2 8.9 .39 .80 <1.0 1.0 2.0 <2.0
12/19 7.4 7.2 .55 .55 2.0 12 9.0 <2.0
1/2/78 7.7 7.8 .67 1.05 <1.0 1.0 1.5 <2.0
1/9 7.1 5.6 .76 .90 <1.0 1.0 2.5 <2.0
1/23 7.1 3.3 1.3 1.0 1.0 1.0 1.0 <2.0
1/30 7.2 3.3 .74 .80 1.0 2.0 9.5 <2.0
2/13 7.2 3.9 1.1 .55 <1.0 1.0 62 2.0
2/20 7.1 3.3 1.1 .80 <1.0 1.0 81 <2.0
2/27 7.3 3.9 .96 .80 <1.0 1.5 79 <2.0
3/6 7.2 3 9 .88 .80 1.0 1.5 130 <2.0
3/13 7.3 5.6 .59 .80 <1.0 1.0 1.0 <2.0
3/20 7.2 5.6 1.0 .55 <1.0 1.0 89 <2.0
3/27 7.4 5.6 .74 .90 1.0 16 210 <2.0
4/3 7.3 7.8 1.0 .80 <1.0 16 79 <2.0
4/10 7.1 10.0 .76 .45 1.0 25 150 <2.0
4/17 7.1 11.1 .64 .45 1.0 13 130 <2.0
4/24 7.5 11.1 1.1 .80 1.5 10 <2.0
5/1 7.2 13.3 .45 .60 4.0 12 <2.0
5/8 7.2 13.3 .40 .55 25 31 <2.0
5/22 7.2 15.6 .21 .80 5.5 14 <2.0
5/29 1.0 17.8 .37 1.0 1.5 <1.0 <2.0
mean .65 .79 6.9 39
std. dev. .26 .21 8.1 49
161
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TABLE D21. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 48
BALTIMORE
Temp. Turbidity free Cl Plate Count Plate Count Plate Count coliform
Week of pH C NTU mg/i 48 hr. 35 C 96 hr. 35CC 9 day 20C MPH/lao ml
7/18/77 7.4 25.6 .58 0 880 1700 2400 <2.0
7/25 7.3 25.6 .65 0 3.5 160 1500 <2.0
8/1 7.2 25.6 .70 0 8.5 500 1300 <2.0
8/8 7.2 25.0 1.1 0 <1.0 260 400 <2.0
8/15 7.2 26.7 .56 0 190 1200 <2.0
8/22 7.4 25.6 .80 0 <1.0 180 170 <2.0
8/29 7.2 25.6 .74 0 <1.0 20 120 <2.0
9/5 7.2 26.7 .50 0 110 610 830 <2.0
9/12 7.3 25.0 .56 0 39 130 970 <2.0
9/19 7.2 25.6 .51 0 64 110 <2.0
9/26 7.4 23.9 .39 0 <1.0 7.5 460 <2.0
10/3 7.4 23.3 .44 0 <1.0 <1.0 1100 <2.0
10/10 7.3 20.6 .54 0 1.0 10 670 <2.0
10/17 7.6 21.1 .55 0 <1.0 9.0 390 <2.0
10/24 7.4 18.9 .64 0 1.0 380 390 <2.0
10/31 7.4 20.0 .49 0 - 310 650 <2.0
11/7 7.4 20.0 .57 0 33 380 1400 <2.0
11/14 7.4 20.0 .78 0 590 920 <2.0
11/28 7.2 17.8 .61 0 1.0 330 2900 <2.0
12/5 7.5 15.6 .78 0 <1.0 370 1600 <2.0
12/12 7.2 14.4 .50 .05 <1.0 34 130 <2.0
12/19 7.4 13.3 .51 0 <1.0 55 1700 <2.0
1/2/78 7.7 14.4 .72 .55 3.5 1.0 170 <2.0
1/9 7.2 10.6 1.1 .30 1.0 7.0 51 <2.0
1/23 7.1. 4.4 .83 .45 5.0 5.0 4.5 <2.0
1/30 7.4 8.9 .93 .05 <1.0 2.0 120 <2.0
2/13 7.4 8.9 1.0 0 1.0 16 530 <2.0
2/20 7.4 11.1 1.0 0 <1.0 46 740 <2.0
2/27 6.8 10.0 .79 0 2.5 88 980 <2.0
3/6 7.4 11.1 .92 0 1.5 180 1200 <2.0
3/13 7.2 11.1 .76 0 1.0 23 980 <2.0
3/20 7.2 11.1 .96 0 1.0 40 290 <2.0
3/27 7.4 11.1 .83 0 1.5 290 2900 <2.0
4/3 7.3 14.4 1.0 0 1.0 28 1100 <2.0
4/10 7.3 14.4 1.1 0 1.0 50 770 <2.0
417 7.3 14.4 .67 0 <1.0 80 1000 <2.0
4/24 7.7 15.6 .69 0 220 1100 <2.0
5/1 7.4 18.9 .66 0 1200 5200 <2.0
5/8 7.4 16.7 .69 0 100 1500 <2.0
5/22 7.4 18.3 1.0 0 690 3500 <2.0
5/29 7.2 20.0 .52 0 470 1300 <2.0
mean .72 .03 240 1091
std. dev. .20 .11 341 1042
162
-------
TABLE D22. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 49
BALT IMORE
Temp. Turbidity free Cl Plate Count Plate Count Plate Count coliforr
Week of pH C NTU m9/l 48 hr. 35CC 96 hr. 35CC 9 day 20CC N/l00 nO
7/18/77 7.2 23.9 .32 1.0 12 16 25 <2.0
7/25 7.2 22.2 .65 1.0 7.5 11 12 (2.0
8/1 7.2 22.2 2.6 1.0 4.0 5.5 4.5 <2.0
8/8 7.0 23.3 .85 1.0 3.5 5.5 5.0 <2.0
8/15 7.0 23.9 1.0 1.0 14 12 <2.0
8/22 7.0 20.0 .51 1.0 3.5 5.5 12 <2.0
8/29 6.9 20.0 .52 1.2 1.5 3.0 1.0 <2.0
9/5 7.1 22.8 .29 1.0 2.5 4.5 5.5 (2.0
9/12 7.1 20.0 .25 1.0 4.5 7.5 13 <2.0
9/19 7.1 23.3 .36 1.2 9.0 11 <2.0
9/26 7.1 20.0 .29 1.2 9.0 11 13 <2.0
10/3 7.2 20.0 .35 1.2 2.0 2.0 3.0 <2.0
10/10 7.1 19.4 .29 1.2 16 21 30 <2.0
10/17 7.2 16.7 .80 1.2 <1.0 6.5 5.5 <2.0
10/24 7.4 16.7 .67 1.2 <1.0 <1.0 <1.0 <2.0
10/31 7.3 15.6 .36 .80 2.0 2.0 7.0 <2.0
11/7 7.4 15.6 .43 .55 19 26 27 <2.0
11/14 7.2 15.6 .40 1.05 9.0 34 18 <2.0
11/28 7.4 13.3 .71 1.2 5.0 5.0 8.5 <2.0
12/5 7.5 10.0 .51 1.0 1.0 1.0 4.5 <2.0
12/12 7.2 9.4 .37 1.0 <1.0 2.0 4.0 <2.0
12/19 7.4 8.9 .42 .55 <1.0 <1.0 4.0 <2.0
1/2/78 7.7 6.1 .64 1.05 1.0 2.5 3.5 <2.0
1/9 7.2 5.6 .60 .80 1.0 4.0 37 <2.0
1/23 7.2 3.3 .61 .90 6.5 8.0 6.0 <2.0
1/30 7.2 3.3 .82 .80 8.0 17 58 <2.0
2/13 7.2 3.9 1.1 .55 2.0 7.0 25 <2.0
2/20 7.2 3.3 .96 .80 1.0 1.5 3.5 <2.0
2/27 7.1 3.9 .69 .80 1.0 1.5 1.5 <2.0
3/6 7.3 3.9 .79 .80 1.0 2.5 21 <2.0
3/13 7.3 4.4 .51 .80 <1.0 1.0 3.0 <2.0
3/20 7.2 6.1 1.1 .80 1.0 2.0 4.5 <2.0
3/27 7.0 7.2 .71 .80 14 21 72 <2.0
4/3 7.2 8.9 1.0 .55 1.0 3.0 4.5 <2.0
4/10 7.1 12.2 .88 .80 1.5 1.5 5.0 <2.0
4/17 7.1 12.2 .44 .80 2.0 2.0 13 <2.0
4/24 7.5 12.2 .50 .80 7.0 18 <2.0
5/1 7.4 12.2 .34 1.05 3.0 15 <2.0
5/8 7.2 14.4 .46 .80 1.0 8.0 <2.0
5/22 7.0 16.7 .24 1.0 23 19 <2.0
5/29 7.0 17.8 .33 1.2 73 71 <2.0
.63 .94 9.1 15
std. dcv. .40 .20 13 17
163
-------
TABLE D23. BIOLOGICAL, CREMICAL, ANI) PHYSICAL DATA, STATION 52
BALT fl4ORE
Teip. Turbidity free C i Plate Count Plate Count Plate Count coli form
Week of pH C W Il l i g/l 48 hr. 35C 96 hr. 35 C 9 day 20C MPN/l00 ml
7/18/77 7.4 20.0 .40 .80 1.5 4.0 <2.0
7/25 7.2 24.4 .50 .80 <1.0 2.0 <1.0 <2.0
8/1 7.2 23.9 1.6 .30 <1.0 1.0 <1.0 <2.0
8/8 7. 22.8 .80 .80 <1.0 (1.0 1.0 <2.0
8/15 7.0 23.3 .46 .55 <1.0 1.5 <2.0
8/22 7.1 20.6 .50 .80 120 130 120 <2.0
8/29 7.1 20.0 .36 .80 8.0 18 28 <2.0
9/5 7.1 23.3 .42 .80 1.0 3.5 5.5 <2.0
9/12 7.2 20.0 .25 .55 <1.0 1.0 <1.0 <2.0
9/19 7.2 21.1 .42 .90 <1.0 <1.0 <2.0
9/26 7.2 20.0 .34 .80 1.0 1.0 1.0 <2.0
10/3 7.3 20.0 .39 .80 1.0 2.5 <1.0 <2.0
10/10 7.1 20.0 .40 .80 <1.0 <1.0 <1.0 <2.0
10/17 7.2 16.7 .57 .80 1.0 <1.0 <1.0 2.0
10/24 7.4 15.6 .74 .55 1.0 <1.0 2.5 <2.0
10/31 7.3 15.0 .43 .80 1.0 <1.0 1.0 2.0
11/7 7.4 14.4 .46 .30 <1.0 <1.0 2.5 (2.0
11/14 7.4 13.3 .60 .30 <1.0 <1.0 <1.0 <2.0
11/28 7.2 12.2 .52 1.0 7.0 7.0 3.0 <2.0
12/5 7.4 10.0 .69 .80 <1.0 <1.0 1.0 2.0
12/12 7.1 8.9 .36 1.0 1.0 1.0 1.0 <2.0
12/19 7.4 7.8 .75 .80 1.0 1.0 <1.0 2.0
1/2/78 7.8 4.4 .65 1.05 12 17 11 2.0
1/9 7.2 3.3 1.1 1.0 1.0 1.0 1.0 2.0
1/23 7.4 3.3 .58 .80 2.0 2.0 LO <2.0
1/30 7.2 3.3 .88 .30 <1.0 <1.0 2.0 <2.0
2/13 7.2 3.3 1.1 .55 4.0 17 21 <2.0
2/20 7.4 2.8 1.1 .55 <1.0 1.0 <1.0 2.0
2/27 7.0 3.3 1.0 .80 1.0 1.0 1.0 <2.0
3/6 7.2 3.3 .80 .55 1.0 1.0 1.0 2.0
3/13 1.2 3.3 .71 1.0 1.0 1.5 <1.0 <2.0
3/20 7.6 5.6 1.0 .80 1.0 1.0 <1.0 2.0
3/27 7.4 5.6 .78 .80 <1.0 <1.0 13 33
4/3 7.2 7.2 .96 .80 <1.0 1.0 <1.0 <2.0
4/10 7.2 10.0 1.1 .55 1.0 1.0 1.0 <2.0
4/17 7.3 11.1 .54 .80 <1.0 <1.0 <1.0 <2.0
4/24 7.5 12.2 .58 .55 <1.0 1.0 <2.0
5/1 CLOSED
5/9 7.1 12.2 .43 .80 1.0 <1.0 <2.0
5/22 7.2 14.4 .43 .80 <1.0 3.0 <2.0
5/29 7.2 15.6 .45 .80 3.0 1.0 <2.0
.65 .73 5.5 5.7
std. 4ev. .29 .20 20.7 19.7
164
-------
TABLE D24. BIOLOGICAL, CHEMICAL, AND P1 SICAL DATA, STATION 53
BALT INORE
Temp. Turbidity free Cl Plate Count Plate Count Plate Count coliform
Week of pH C NTU mg/i 48 hr. 35 C 96 hr. 35CC 9 day 20
-------
TABLE D-25. BIOLOGICAL, CHEMICAL, AND PHYSICAL DATA, STATION 54
BALTIMORE
Temp. Turbidity free Cl Plate Count Plate Count Plate Count co1iforr
Week of pH C NTU ing/l 48 hr. 35 C 96 hr. 35CC 9 day 20CC MPN/100 ml
7/18/77 7.4 18.3 .30 .80 5.0 270 8.0 <2.0
7/25 7.3 21.1 .45 .55 4.0 7.0 3.0 <2.0
6/1 CLOSED
8/8 7.2 23.3 1.5 .55 1.0 1.0 1.0 <2.0
8/15 7.2 22.2 .60 .55 1.0 1.0 <2.0
8/22 7.4 20.6 .39 .55 5.0 7.5 1.0 <2.0
8/29 7.2 22.2 .41 .30 7.0 18 8.5 <2.0
9/5 7.5 20.0 .41 .80 10 10 3.0 <2.0
9/1 ? 7.2 20.0 .29 .80 1.0 1.0 <1.0 <2.0
9/19 7.4 18.9 .36 .55 <1.0 <1.0 <2.0
9/26 7.2 20.0 .38 .55 <1.0 1.0 1.0 <2.0
10/3 7.4 18.3 .35 .55 <1.0 1.0 1.0 <2.0
10/10 7.4 18.9 .40 .45 <1.0 <1.0 <1.0 <2.0
10/17 7.3 15.0 .53 .80 <1.0 24 <1.0 <2.0
10/24 7.7 15.6 .43 .55 1.0 1.0 1.0 <2.0
10/31 7.4 16.7 .34 .55 5.5 11 7.5 <2.0
11/7 7.4 14.4 .45 .80 1.0 5.0 5.5 <2.0
11/14 7.4 12.8 .55 .80 1.0 10 1.0 <2.0
11/28 7.4 13.3 .70 .80 2.0 2.5 13 <2.0
12/5 7.8 12.2 .49 .55 3.0 29 16 <2.0
12/12 7.6 7.8 .50 .55 1.0 3.0 3.0 <2.0
12/19 7.6 7.8 .56 .80 4.5 10 12 <2.0
1/2/78 8.1 6.7 .61 .45 17 29 16 <2.0
1/9 7.4 3.9 .69 .55 1.0 4.5 3.5 <2.0
1/23 7.4 3.9 1.1 .55 2.5 8.0 3.5 <2.0
1/30 7.4 3.9 1.4 .80 140 160 150 2.0
2/13 7.4 3.9 1.0 .80 2.0 4.5 1.5 <2.0
2/20 7.4 3.9 1.1 .55 3.5 6.0 4.5 <2.0
2/27 7.5 3.9 1.0 .80 2.5 3.5 3.5 <2.0
3/6 7.4 3.9 .65 .80 9.5 23 20 <2.0
3/13 7.4 5.6 1.0 .80 7.0 9.0 8.0 <2.0
3/20 7.4 5.6 .96 .80 2.5 4.0 2.5 <2.0
3/27 7.4 6.7 .83 .75 1.5 3.5 7.0 <2.0
4/3 7.5 8.3 1.0 .45 2.5 2.5 <1.0 <2.0
4/10 7.3 12.2 1.0 .55 36 40 39 <2.0
4/17 7.4 11.1 .75 .55 9.0 18 13 <2.0
4/25 7.4 12.2 .74 .80 15 4.0 <2.0
5/1 7.2 13.3 .41 .80 24 9.0 <2.0
5/8 7.4 12.2 .43 . 55 20 85 2.0
S/22 7.4 15.6 .27 .80 1.0 3.0 <2.0
5/29 7.4 16.1 .35 .55 4.0 4.5 <2.0
65 20 12
mean .
48 27
std. dev. .31 .14
166
-------
APPENDIX E. MAJOR BIOCHEMICAL GROUPS
TABLE E1 .
35°C
MAJOR BIOCHEMICAL GROUPS AT STATION 1, FREDERICK
20°C
0 )
U )
C)
4.)
a)
4.)
Iti
H
H
0
U )r-
1 1dP
0
cn .1
I44
r-4
(
()
-4
E
C)
0Q
0 i
00
H$4
O
4 .
OU
C)
$14J
Wrt
Q
80
U )
Z -i
4
H C
t 0
4JQ
0 4.)
4J 4
CJ4J
4 Cf )
08
4J
Cn1
-4 .r-1
(
4JUD
Qa)
4J.lJ
( Q
4---4
000
O ) -
0
,0
00
C.-
Q)4J
b H
Q)O
4U )
r-
0
H
8
0.)
.004
0
00
r4
O
q .
0U)
a)
14-3
G)(
.QH
80
U)
Z-
H
r-4 C
4JQ 4
0 4 .J
J - i
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0
p4.)
IP C
0
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OC)
l.4-
( Q 4
U- r-
000
0
-
i 0
00
.4
0. )4
0 H
a )0
4U)
8
26
5.8
4.3
34.6
9
19
4.2
2.0
38.5
9
17
3.8
4.1
30.8
8
85
18.9
11.5
57.7
26
3
0.7
1.4
11.5
3
77
17.1
35.5
61.5
3
57
12.7
29.7
38.5
26
5
1.1
2.7
11.5
24
0
24
10
2.2
5.5
7.7
17
3
0.7
1.9
11.5
17
1
0.2
0.6
3.8
10
62
13.8
40.0
34.6
22
11
2.4
6.6
15.4
18
4
0.9
4.1
15.4
18
16
3.6
13.3
15.4
22
7
1.6
7.2
7.7
5
8
1.8
13.3
26.9
5
2
0.4
2.4
7.7
1 .].
54
12.0
93.1
30.8
13
48
10.7
71.6
30.8
6
12
2.7
26.7
26.7
16
43
9.6
66.2
30.8
14
14
3.1
31.8
11.5
28
23
5.1
35.9
7.7
10
17
3.8
44.7
23.1
6
5
1.1
7.9
11.5
27
3
0.7
8.6
7.7
14
12
2.7
23.1
19.2
2
27
6.0
79.4
30.8
11
21
4.7
43.8
26.9
28
23
5.1
69.7
11.5
27
35
7.8
76.1
15.4
1
15
3.3
48.4
34.6
1
17
3.8
45.9
23.1
30
1
0.2
3.1
3.8
167
-------
TABLE E2.
MAJOR BIOCHEMICAL GROUPS AT STATION 4, FREDERICK
35°C
20°C
.-4
U
C)
4
E
U)
. Ql
O
00
p t
$-
0 a )
a)
$ .44J
W(
0
Z )-4
o
w
4. )
l
1-4
0
($)
I
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1-J0.-l
0 4.)
4J .t U
a). ).)
4- )0U)
O
4 . )
C
,-4 .-4
tU
4JU)
0a)
4)4.1
Q 4
φ .4 j
000
4
44
0
00
. -i
a) 4 )
tu
b 1 r-4
WO
4U
r14 ..4
,-
IU
C)
-l
E
j
U
00
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Q
t4
0 a )
44. )
a)tu
o, -
o
(I1
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a)
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tu
r-
0
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iUIl-40
4- 0-4
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0
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t-1.. -i
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co
4 4dP
0
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00
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a )
0 )0
) .4U)
iz 4 ..-
8
161
26.5
26.9
84.6
9
56
11.5
5.8
58.3
9
100
16.5
24.1
65.4
8
84
17.3
11.4
75.0
26
60
9.9
28.3
53.8
3
40
8.2
18.4
62.5
3
20
3.3
10.4
30.8
26
46
9.5
24.9
41.7
24
25
4.1
13.6
38.5
24
32
6.6
17.7
45.8
17
36
5.9
22.2
38.5
17
18
3.7
10.6
25.0
10
0
22
51
10.5
30.5
45.8
18
17
2.8
17.3
34.6
18
49
10.1
40.8
50.0
22
31
5.1
32.0
42.3
5
6
1.2
10.0
20.8
5
6
1.0
7.2
15.4
11
3
0.6
5.2
4.2
13
4
0.7
6.0
11.5
6
5
1.0
11.1
12.5
16
0
14
1
0.2
2.3
4.2
28
0
10
0
6
10
1.6
15.9
3.9.2
27
2
0.4
5.7
4.2
14
17
2.8
32.7
15.4
2
1
0.2
2.9
4.2
11
3
0.5
6.3
11.5
28
0
27
2
0.3
4.3
3.8
1
14
2.9
45.2
12.5
1
5
0.8
13.5
19.2
30
5
0.8
15.6
15.4
168
-------
TABLE E3. MAJOR BIOCHEMICAL GROUPS AT STATION 27, BALTIMORE
35°C
20°C
.-
0
6
0)
Q
0
00
,.-l) .4
1 . -i
OU)
W
4J
a)r
Q 4
EQ
U)
z._l
U)
a)
4 - )
(
ON
tfl(N
- -4
a 4-iQ
4. )O-4
0 4-
0.34-)
4 . 4 .Q J)
06
4J
f0
4 -ldP
0
r4 r1 -
>
4- (fl 00
00) r-4
44 0)4.)
4 -lr ..l
000 0)0
U) 4 4U)
dP 40 z -.4
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0
4
6
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0
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-1
4-4
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0)
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0)0)
.Q 4
EQ
U)
Z- 4
U)
w
4-
(
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4Ju
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1
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U)
ii-d
8
34
14.8
5.7
47.6
9
121
31.1
12.6
70.8
9
12
5.2
2.9
23.8
8
121
31.1
1.6.4
62.5
26
6
2.6
2.8
14.3
3
13
3.3
6.0
37.5
3
4
1.7
2.1
14.3
26
7
1.8
3.9
16.7
24
0
24
11
2.8
6.1
8.3
17
3
1.3
1.9
9.5
17
17
4.4
10.0
25.0
10
48
21.0
31.0
38.1
22
2
0.5
1.2
8.3
18
3
1.3
3.1
9.5
18
2
0.5
1.7
8.3
22
0
5
31
8.0
51.7
33.3
5
41
17.9
49.4
14.3
11
0
13
12
5.2
17.9
19.0
6
6
1.5
13.3
20.8
16
1
0.4
1.5
4.8
14
2
0.5
4.5
4.2
28
3
1.3
4.7
9.5
10
18
4.6
47.4
12.5
6
5
2.2
7.9
14.3
27
15
3.9
42.9
16.7
14
11
4.8
21.2
14.3
2
0
11
12
5.2
25.0
19.0
28
1
0.3
3.0
4.2
27
2
0.9
4.3
9.5
1
0
1
0
30
3
1.3
9.4
9.5
169
-------
TABLE E4. MAJOR BIOCHEMICAL GROUPS AT STATION 34, BALTIMORE
35°C
20°C
U)
U )
w
-p
t
,-l
a)
4 )
c
I
(
()
-H
E
a)
.OQ
0
00
-H ( -
O
t
OU)
a)
4-& -
C)tU
Q , ..
80
U)
Z-H
0 .
corn
-H
r I 0
(U 4-10
-4-J0-.-4
0 1-
.P ( -4CU
a)4 )
t4 U)
0
4 J
0
0
H
(
4JU)
OQ)
4J J
4-a 4 i
000
Cn ( -I
dO -H 0
4- dp
0
>i O
00
OH
QJ4 .
01
a)0
- (U,
1X -H
I
0
H
8
a)
.CQ
0 )
00
-H ( -4
Ott )
Q )
4J
a)(
.Q -
EQ
U)
Z-H
0 .
tarn
H
0
4- o
JQ-H
0 -1-i
4J ( - (
Q)J.J
4-1 U)
08
4J
0
0
r- -4
a
-(-U)
0 )
.4J4.J
( Q
.H -l
000
U)
dO-H0
t44 ip
0
> 0
00
0-H
OJ4
U )0
( - tt)
-H
8
115
31.4
19.2
76.0
9
76
14,9
7.9
88.0
9
78
21.3
18.8
56.0
8
137
26.9
18.5
96.0
26
50
13.7
23.6
44.0
3
11
2.2
5.1
28.0
3
24
6.6
12.5
32.0
26
72
14.1
38.9
52.0
24
4
1.1
2.2
4.0
24
14
2.8
7.7
20.0
17
28
7.7
17.3
36.0
17
74
14.5
43.5
60.0
10
0
22
21
4.1
12.6
36.0
18
3
0.8
3.1
8.0
18
1
0.2
0.8
4.0
22
9
2.5
9.3
24.9
5
11
2.2
18.3
4.0
5
3
0.8
3.6
8.0
11
0
13
2
0.5
3.0
4.0
6
2
0.4
4.4
4.0
16
3
0.8
4.6
12.0
14
25
4.9
56.8
12.0
28
0
10
0
6
2
0.5
3.2
8.0
27
0
14
2
0.5
3.8
4.0
2
0
11
0
28
0
27
0
1
0
1
0
30
1
0.3
3.1
4.0
170
-------
TABLE E5
MAJOR BIOCHEMICAL GROUPS AT STATION 37, BALTIMORE
35°C
20°C
.- l
r
0
-.-4
E
U
.ca
0
00
d
O
4- 4
OU)
a
-44-
w
Q, .4
0
U)
Z--4
0)
0 )
.)
( ,
- i
Or
u,m
1
( 4-40
4 10- -4
0 . J
4- 4(0
0 )4.J
44.0(L)
OE
4
(0
i
n
-JU)
00)
4 14
10O.
4-1 -4
000
(I) 4
oP- - I 0 -
4- loP
0
>
00
c - 4
W4-
c0
t 4
0)0
4(I)
c- i
r l
flS
0 44
l OU)
E 0)
0) 44-
0)10
0 Q
00 O
-4 -4
Zr1
W
0)
4i
(
, -4
ON
u
.4
r .l
(04-40
4.)Q.r-4
0 4-
4 - l ( 0
0)4J
U-4 .OUD
08
4.J
OP 10
r-4 H
10
4)U)
00)
4 4 )
(004
4-4 .-4
000
W 4
dP-I 0
4-4 oP
0
00
. -4
Q)4i
(0
0 -i
0)0
-4U)
Lx d
8
73
19.9
12.2
78.3
9
232
56.7
24.1
81.8
9
54
14.7
13.0
60.9
8
64
15.6
8.6
77.3
26
37
10.1
17.5
43.5
3
41
10.0
18.9
59.1
3
58
15.8
30.2
69.6
26
15
3.7
8.1
31.8
24
19
5.2
10.3
26.1
24
4
1.0
2.2
9.1
17
16
4.4
9.9
39.1
17
9
2.2
5.3
31.8
10
0
22
17
4.2
10.2
22.7
18
10
2.7
10.2
26.1
18
2
0.5
1.7
9.1
22
23
6.3
23.7
34.8
5
1
0.2
1.7
4.5
5
6
1.6
7.2
13.0
11
0
13
0
6
2
0.5
4.4
9.1
16
3
0.8
4.6
13.0
14
0
28
0
10
0
6
6
1.6
9.5
13.0
27
0
14
5
1.4
9.6
13.0
2
2
0.5
5.9
9.1
11
0
28
0
27
0
1
0
1
12
3.3
32.4
4.3
30
3
0.8
9.4
13.0
171
-------
TABLE E-6. MAJOR BIOCHEMICAL GROUPS AT STATION 43, BALTIMORE
35°C 20°c
U)
a)
4. 4 .
g o
p . 4
0 om
WdP U )
p - I 0 p .4 -- 0
go r-I . .. .i go
c 4.-
o 4 . 4 g o4.io go C) 4 - 4 go 1.IO go
4 00) 4- O . - 4 4Jtfl 00 Oco 4 . 0 -- I 4 . U) 00
E 0 4. Ow -4 E a) 0 4- Ow
14 .4 . 440 4 4 0 )4. ) 0 ) 144 . p140) .4.14 . ) 0 )4 )
. Q 4 0)40 0)4 ) 0 )40 0)4)
°
00 0 0 000 0)0 00 0 OE 000 0)0
0 ) 1 1 )14 140) r44.4 . U ) 0) 1.4 (0
Z.- (0 I 0 r .-I tflL ) Z-i . 40 .-4
B 37 10.5 6.2 33.3 9 30 9.1 3.1 41.7
9 45 12.7 10.8 58.3 8 66 19.9 8.9 45.8
26 4 1.1 1.9 12.5 3 10 3.0 4.6 20.8
3 7 2.0 3.6 8.3 26 5 1.5 2.7 20.8
24 110 31.2 59.8 62.5 24 93 26.1 51.4 58.3
17 30 8.5 18.5 45.8 17 7 2.1 4.1 20.8
10 0 22 31 9.4 18.6 25.0
18 55 15.6 56.1 37.5 18 40 12.1 33.3 37.5
22 4 1.1 4.1 8.3 5 0
5 0 11 0
13 0 6 4 1.2 8.9 8.3
16 2 0.6 3.1 8.3 14 0
28 0 10 0
6 8 2.3 12.7 16.7 27 1 0.3 2.9 4.2
14 1 0.3 1.9 4.2 2 0
11 3 0.8 6.3 8.3 28 0
27 0 1 0
1 2 0.6 5.4 12.5
30 6 1.7 18.8 12.5
172
-------
TABLE E7. MAJOR BIOCHEMICAL GROUPS AT STATION 44, BALTIMORE
35°C 20°C
U) U)
G)
4 J 4- )
-4
0. . 0
tfl
4 0 4 0
1-4 r -I --4 4 r-4 - . 4
0 (1-1 £X κ-40 0 4-i 4 L1 - 4 0 (d
01$) 4.)0 4 4JU) 00 -.4 01$) 40-4 4 U) 00
E a) 0 4 . 0 1 $) 1$ ) 0 4 ) QQ)
44J 4J 4( 4. )4 i a ) 4 - .1) 1.44J $.11 4J4J
. Q 4 W 3)4- W a ) w 4 .J
0 0 -4 4 auj U-i,- y,-i 0 Q -4 4 -4.QU 44 -1 0
00 0 OE 000 WO 00 E0 0 000 WO
.-4 1 U ) Cfl 4U) .-4 4 U ) 4J U)
O Z -. - 4 P W .-4b z .4 Z--4 dP- . 4 X4 - . -1
8 75 19.4 12.5 88.0 9 185 38.1 19.2 100.0
9 24 6.2 5.8 44.0 8 116 23.9 15.7 80.0
26 29 7.5 13.7 40.0 3 15 3.1 6.9 24.0
3 12 3.1 6.3 28.0 26 18 3.7 9.7 32.0
24 22 5.7 12.0 16.0 24 14 2.9 7.7 16.0
17 25 6.5 15.4 28.0 17 17 3.5 10.0 28.0
10 45 11.7 29.0 36.0 22 22 4.5 13.2 32.0
18 4 1.0 4.1 12.0 18 10 2.1 8.3 36.0
22 20 5.2 20.6 28.0 5 2 0.4 3.3 8.0
5 22 5.7 26.5 24.0 11 1 0.2 1.7 4.0
13 1 0.3 1.5 4.0 6 10 2.1 22.0 28.0
16 6 1.6 9.2 8.0 14 2 0.4 4.5 8.0
28 38 9.8 59.4 20.0 10 3 0,6 7.8 8.0
6 12 3 .1 19.0 24.0 27 14 2.9 4.0 12.0
14 3 0.8 5.8 12.0 2 3 0.6 8.8 4.0
11 9 2.3 18.8 16.0 28 9 1.9 27.3 8.0
27 7 1.8 15.2 16.0 1 2 0.4 6.5 4.0
1 1 0.3 2.7 4.0
30 7 1.8 21.9 - 8.0
173
-------
TABLE E-8. MAJOR BIOLOGICAL GROUPS AT STATION 48, BALTIMORE
35°C
20°C
U)
U)
0 )
0)
4)
ni
4)
(U
.-4
.4
(0
0
.4
E
U)
0
00
O
4
0U
U)
4J
W (U
Q .4
0
U)
Z-l
.-1
0
U)c
.i
cU440
4.iQ 4
0 4.
-) (U
C) . )-)
4-l .QC/
0
4J
(U
r-4 .-l
(U
4-)U)
0 )
4J4)
( U0
- -
000
W
--4 0
t (.1d
0
>,
00
0)4 )
( U
0 -
0)0
1UI
x4 4
-4
( 0
0
0 )
.c0
0
00
-4
O
44
0cl)
w
4 )
0) ( U
0
W
Z-4
0
.4
,. .
fΨ 4- (0
4J0- 4
0 4)
4) ( U
0)4-
4- ( U)
0
4J
dP I (0
::
4 .,.4
(U
4JU
00)
4 )4 )
(004
(-4 .-4
000
U )
-.-l 0
0
>
00
r-
0)43
( U
C) -4
0)0
) 1(1)
--1
8
9
26
3
24
17
10
18
22
5
13
16
28
6
14
11
27
77
85
23
10
4
21
2
3
3
7
15
1
27.4
30.2
8.2
3.6
1.4
7.5
0.7
1.1
1.1
2.5
5.3
0.4
12.9
20.5
10.8
5.2
2.2
13.0
2.0
3.1
3.6
10.8
23.8
1.9
66.7
70.8
16.7
12.5
4.2
16.7
0
4.2
8.3
4.2
0
12.5
0
12.5
4.2
0
0
9
8
3
26
24
17
22
18
5
11
6
14
10
27
2
28
1
244
67
10
17
3
27
12
1
4
1
59.7
16.4
2.4
4.2
0.7
6.6
2.9
0.2
1.0
0.2
25.3
9.1
4.6
9.2
1.7
15.9
7.2
1.7
8.9
8.8
91.7
54.2
29.2
20.8
4.2
33.3
25.0
0
4.2
0
12.5
0
0
0
4.2
0
0
1
0
30
6
2.1
18.8
12.5
174
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO. 2.
EPA600/280OlO
3. RECIPIENT S ACCESSION NO.
4. TITLE AND SUBTITLE
BENEFITS OF MAINTAINING A CHLORINE RESIDUAL IN WATER
SUPPLY SYSTEMS
5. REPORT DATE
June 1980 (Issuing Date)
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Michael C. Snead, Vincent P. Olivieri,
Cornelius W. Krus , and Kazuyoshi Kawata
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
The Johns Hopkins University School of Hygiene and
Public Health
Division of Environmental Health Engineering
615 N. Wolfe Street, Baltimore, Maryland 21205
10. PROGRAM ELEMENT NO.
1CC 824 SOS 2: Task 16
11. CONTRAC+/GRANT NO.
R 804307
12. SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Research Laboratory; Cinn.,OH
Office of Research and Development
U. S. Environmental Protection Agency
Cincinnati, Ohio 45Th8
13. TYPE OF REPORT AND PERIOD COVERED
F in 1 .itiiy 1976Jan. 1979
14.SPONSdRING AGENCY CODE
EPA! 600/14
15. SUPPLEMENTARY NOTES
Project Officer: Martin J. Allen/Raymond H. Taylor (513) 6847204
16. ABSTMACT
The protection afforded the water consumer by the maintenance of a chlorthne residual
in water distribution systems was evaluated in laboratory holding tanks and reservoirs
and existing municipal water distribution systems. In the laboratory studies, tap
water, adjusted to the appropriate pH, temperature, and chlorine residual, was
challenged with with varying levels of autoclaved sewage seeded with Shigeila, Salmonel
coliforms, poliovirus 1, and f2 bacterial virus. Comparative survivals of these
microorganisms were evaluated over two hour periods. As expected microbial inacti-
vation was increased by lower pH, higher temperature, higher initial chlorine
concentration, and lower sewage concentration. An initial free chlorine concentration
was more effective than an equivalent initial combined chlorine residual. The
maintenance of a free chlorine residual was found to be the single most effective
measure for maintaining a low plate count in the distribution system. More than 6000
plate count isolates were studied and classified into functional groups based on seven
biochemical characteristics.
Ii. KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/0PEN ENDED TERMS
C. COSATI Field/Group
Chlorination
Potable Water
Coliform Bacteria
Shigella
Salmonella
Water Distribution
Bacterial identif i
cation
Viral Inactivation
Standard Plate Count
13 B
18. DISTRIBUTION STATEMENT
D 1 .
.e. .ease to u ic
19. SECURITY CLASS (This Reporr,J
Unclassified
21. NO. OF PAGES
l89
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Farm 22201 (Rev. 477)
175
US 600EE9HENT P#LNTINO OFFICE 1990 657165/O Z1
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