United States
Environmental Protection
Agency
Mum
' 980
)H 45268
Research and Development
oEPA
Preventing Haloform
Formation in
Drinking Water
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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 tofacilitate 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, nd methodOlogy to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology req ed for the control and treatment
of pollutiori..sources to meet environmental ‘ uŕlity standards.
This document is available to the public through the National Technical Informa-
lion Service, Springfield, Virginia 22161.
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EPA-600/2-80-091
August 1980
PREVENTING HALOFORM FORMATION IN DRINKING WATER
by
Lei and L. Harms
Robert W. Looyenga
South Dakota School of Mines and Technology
Rapid City, South Dakota 57701
Grant No. R805149-01-0
Project Offfcer
0. Thomas Love, Jr.
Drinking Water Research Division
Municipal Environmental Research Laboratory
Cincinnati, Ohio 45268
This study was conducted
in cooperation with
South Dakota School of Mines and Technology
Rapid City, South Dakota 57701
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.
11
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FOREWORD
The U.S. Environmental Protection Agency was created because of increas-
ing 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 testimonies to the deterioration of our natural environment. The
complexity of that environment and the interplay of its components require a
concentrated and integrated attack on the problem.
Research and development is that necessary first step in problem solution;
it involves defining the problem, measuring its impact, and searching for
solutions. The Municipal Environmental Research Laboratory develops new and
improved technology and systems to prevent, treat, and manage wastewater and
solid and hazardous waste pollutant discharges from municipal and community
sources, to preserve and treat 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 and provides a most
vital communications link between the researcher and the user community.
Halogenated organics are produced during the chlorination step in water
treatment. The results of research to minimize the production of these con-
taminants by modifying disinfection practices are examined in this publication.
Francis T. Mayo, Director
Municipal Environmental Research
La bora tory
111
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ABSTRACT
Previous work at Huron, South Dakota had achieved a reduction in halo-
forms in the drinking water delivered to the consumers. However, the concen-
trations of both chloroform and bromodichloromethane were still considered
to be excessive, primarily due to the growth of these compounds within the
distribution system.
The water distribution system was monitored for trihalomethanes at
several locations. Deposits from within the distribution system were
evaluated as potential precursor material and were found to be precursors for
the haloform reaction. Field tests designed to determine the extent of tn-
halomethane formation which occurs as a result of the pipe deposits were
inconclusive. It appears that the deposits are a precursor source, but they
do not substantially alter the terminal trihalomethane concentration.
Aninonium sulfate was used to convert to a combined chlorine residual
in the distribution system. A significant drop in trihalomethane concen-
trations was obtained while still maintaining adequate disinfection. Primary
disinfection was obtained by lime softening followed by a free chlorine resi-
dual.
Land used upstream from the raw water intake was evaluated for poten-
tial chloroform formation. Peak concentrations occurred near marshes, where
cattle watered, and where the river was stagnant.
Nine raw water quality parameters were monitored and correlated with
ThM formation. The best correlations were obtained with specific conductance
and turbidity.
This report was submitted in fulfillment of Grant No. R805149-Ol by the
South Dakota School of Mines and Technology under the sponsorship of the U.S.
Environmental Protection Agency. This report covers a period of from May 23,
1977 to June 20, 1978 and work was completed as of February 28, 1979.
iv
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CONTENTS
Foreword
ill
Abstract
iv
Figures
Tables
V•1•l
V fl I
List of Abbreviations and Symbols.
Acknowl edgments
ix
X
1. Introduction
1
General
1
Scope of Work
2. Conclusions
1
3
3. Recomendations
4
4. Previous Research at Huron
5
Introduction
5
Results
5
Recommendations
. .
5
5. Water Treatment at Huron
. .
7
History . .
James River Water Quality.
Treatment Process of the
7
8
9
Treatment Process of the
11
6. Experimental Methods
General
15
15
Field
15
Sampling Stations . . .
Sampling Location . . .
Sample Handling
Field Tests
.
.
15
16
16
18
Laboratory
Reagents
Analytical Procedures .
7. Results
.
18
18
18
24
Distribution System
Raw Water Parameters . . .
.
. .
. .
.
.
24
28
Temperature
Specific Conductance. .
Turbidity
Land Use
.
. .
. .
. .
. .
.
.
.
.
29
29
29
36
Seasonal Variations . .
.
. .
.
36
Monitoring Trihalomethanes
Disinfection with pH
.
. .
.
39
39
1949 Plant:
1978 Plant.
V
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CONTENTS (Continued)
Previous Experience Using Combined Chlorine
Kinetics of Chioramine Formation
Simulation of Disinfection with Chioramines
Start-up Using Combined Chlorine
Full-Scale Operation with Combined Chlorine
Operation with Combined Chlorine
Economics
45
48
49
51
52
56
58
References
Appendices
.60
A. Full Plant and Distribution System Data
B. Residence Time in the Distribution System
C. Pipe Material Test
D. In Pipe Test
E. Raw Water Quality Data
F. PTHM Vs. Chlorine Dose
G. Chlorine Dose at the Treatment Plant
H. River Trip Data
I. Total Organic Carbon Data
J. Total Coliform Data
K. Artificial Spiking Data
62
71
72
74
77
79
81
82
84
85
.88
vi
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FIGURES
Number Page
1 Process Flow Diagram for Water Treatment at Huron
Prior to December 1977 10
2 Process Flow Diagram for Water Treatment at Huron
After December 1977 12
3 Sampling Station in the Distribution System 17
4 Graphical Representation of Four Trihalomethane Parameters . . 20
5 Potential Chloroform Concentration From Pipe Material
at a Chlorine Dose of 3.43 mg/i 25
6 Potential Chloroform Concentration From Pipe Material
at a Chlorine Dose of 18.2 mg/i 27
7 PTHM vs. Chlorine Dose (5/10/78) 30
8 Effect of Raw Water Temperature on Chloroform Concentration 31
9 Effect of Temperature on CHC1 3 Formation at pH 11 . . . . 32
10 Specific Conductance as an Indicator of Potential
Chloroform Concentration 33
11 Effect of Time and pH on CHC1 3 Formation at 20°C 34
12 Turbidity as an Indicator of Chloroform Concentration 35
13 Potential Chloroform Formation Within the James River . . 37
14 Variation of Chloroform Concentration 38
15 Variation of Bromodichioromethane Concentration 40
16 Coliform Disinfection by pH 42
17 Comparison of Germicidal Efficiency of Hypochiorous acid,
Hypochiorite Ion, and Monochloramine 46
18 THM Reduction Using Ammonium Sulfate 55
vii
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TABLES
Number Page
1 James River Water Quality (4) 8
2 Typical Chemical Feed Rates at Water Plant Prior
to December 1977 11
3 Chemical Feed Rate (Typical) at Water Plant After
December 1977 14
4 Laboratory Tests and Procedures of Analysis 21
5 Total Organic Carbon Concentrations on February 14, 1978. .26
6 Optimum pH Ranges for Some Comon Bacteria (16) 41
7 Reduction in Total Coliforms From Station 2N to
Station 5N Due to Lime Softening 43
8 Incubation of 100 Cells/ml of Pathogens in Limed Water . .44
9 Incubation of 1,000 Cells/mi of Pathogens in Limed Water. .44
10 Results of Chioramination Simulation 50
11 Comparison of Two Different Ratios of Chlorine to
Munonia-Nitrogen 52
12 NM Concentrations During Transition Period 54
13 THM Concentrations on June 27, 1978 57
14 A mionia Concentrations Which Result in 0.2 mg/i
Unionized Anaiionia (NH 3 ) 57
15 Effect of Chlorine Vs. Chioramines on Total Plate Counts. .58
16 Estimated Costs of Disinfection Alternatives for a 5
MGDP1ant 59
v i i i
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LIST OF ABBREVIATIONS AND SYMBOLS
ABBREV IAT IONS
EPA --United States Environmental Protection Agency
NORS --National Organics Reconnaissance Survey
THM --Trihalomethane(s)
ppb —-Part per billion
eqn --Equation
Inst THM --Instantaneous Trihalomethane Concentration
Term THM --Terminal Trihalomethane Concentration
THMFP --Trihalomethane Formation Potential
TTHM --Total Trihalomethane Concentration
PTHM --Potential Trihalomethane
cfs --Cubic feet per second
BDCM --Bromodichloromethane
CHC1 3 --Chloroform
ND --Not Detectable
ix
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ACKNOWLEDGMENTS
The cooperation of the municipal officials and employees at Huron,
South Dakota is gratefully acknowledged. Special appreciation is extended
to Mr. Glenn Housiaux, City Engineer; Mr. Harold Root, Water Treatment Plant
Superintendent; and the operating staff of the Huron Water Treatment Plant.
The research was truly a team effort. Messrs. Tom Norman, Dan Hoyer,
and P. A. Sachdev were deeply involved in both field and laboratory work.
Mr. Larry Doss was the field engineer on site in Huron. Bacteriological
testing dealing with pathogens was conducted in the laboratories at South
Dakota State University, and supervised by Dr. Paul Middaugh.
Technical assistance and support were given throughout the project
by Mr. A. A. Stevens and Dr. 0. T. Love of EPA 1 s Municipal Environmental
Research Laboratory.
x
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SECTION 1
INTRODUCTION
General
A drinking water quality survey conducted by EPA identified high levels
of certain organic compounds in the drinking water at Huron, SD (1). In
order to provide technical assistance to the City of Huron to aid in cor-
recting the problem, a federal grant allowed an on-site investigation which
led to some treatment modifications (2). The formation of chloroform was
substantially reduced during the water treatment process.
Although the initial work at Huron did improve the water quality, it
was felt that additional work could result in still lower trihalomethane
levels in the water. Also, the study raised some questions regarding the
formation of organic compounds within the distribution system and sources
Of precursors. Consequently, an additional project was begun at Huron and
the results of this work are reported in this document. The specific objec-
tives of the new ‘project were:
(1) Study the use of chioramines as a disinfectant and, if suitable,
adapt this disinfection procedure to the full-scale water treat-
ment process at Huron to obtain total haloform reduction.
(2) Monitor the distribution system to detect aftergrowth of halo-
forms in the system, and determine if this aftergrowth is a
result of precursors present in the distribution system.
(3) Attempt to reduce the potential for chlorinated hydrocarbon
formation by identifying the primary source(s) and recommending
steps to reduce the precursors. Sources to be considered are
agricultural runoff, point sources, and biological growths in
stagnant water.
(4) Substantially reduce the bromodichioromethane formed in the
water treatment process.
Scope of Work
All field work was conducted in or near the city of Huron, South Dakota.
Samples were collected from the water treatment plant and the distribution
system which serves the citizens of Huron. Samples were not collected from
pilot plant facilities or other microscale operations.
1
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Background data on the water treatment processes, the raw water quality,
and haloforms in the distribution system were collected during the summer and
early fall of 1977. During this time, the water treatment plant at Huron was
undergoing expansion and modification. Start-up of the altered treatment
began in December of 1977 with several start-up problems, as would be ex-
pected. Initial experimentation with the use of chloramines as a disin-
fectant (the an onia being supplied from amonium sulfate) resulted in the
full-scale application of this process in early May of 1978. Extensive
monitoring was conducted until early June. Raw water quality and haloforms
within the distribution system were also monitored during this period.
The majority of the analytical work was performed on the campus at the
South Dakota School of Mines and Technology. Periodically some testing was
done in the laboratory at the Huron Water Works. Total plate counts and
some pathogenic work was done through a cooperative agreement with South
Dakota State University.
2
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SECTION 2
CONCLUSIONS
1. Disinfection is effectively achieved by the lime softening process in
which the pH is raised above eleven.
2. Maintaining a disinfection residual with combined chlorine is an effec-
tive means of reducing the concentrations of both CHC1 3 and BDCM.
3. Disinfection with combined chlorine eliminated taste and odor problems
at Huron.
4. The proper application of combined chlorine can be the most economical
means of reducing THM concentrations.
5. Ammonium sulfate is a convenient and effective source of ammonia for
chioramine production.
6. The increase in THM concentrations in the Huron distribution system
closely follows residence time.
7. Deposited material within the pipelines of the Huron distribution system
contains organic precursors; however, their contribution to THM forma-
tion appears minimal.
8. Nonprecursor organic material competes favorably for available free
chlorine under chlorine limited conditions. Such conditions lead to
an inverse relationship between THM levels and chlorine demand, and
result in the THM formation being dependent upon the chlorine dose.
9. For the Huron raw water, THMFP is directly related to turbidity and
specific conductance.
10. Growth curves indicate a critical pH above which chlorofo ’m forms much
more readily and to a greater extent.
11. Agricultural runoff appears to be a significant source of precursors for
the haloform reaction, but it does not appear to be a significant source
of bromide.
12. The potential for chloroform formation in the Huron raw water is highest
in areas of marsh growth, where cattle water and where the water is very
stagnant.
3
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SECTION 3
RECOMMENDATIONS
1. Total plate counts of the Huron water should be monitored periodically to
assure that no long term degredation of the drinking water occurs.
2. The type(s) of organic precursors present in agricultural runoff should
be determined in order to aid in planning better land management and
pollution control.
3. A study of the sources of bromide should be made in order to better con-
trol the concentrations of brominated compounds which are potentially
of greater concern than chloroform.
4. A simple qualitative-semiquantitative field test should be developed for
the tn hal omethanes.
4
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SECTION 4
PREVIOUS RESEARCH AT HURON
Introduction
Results of the NORS (1) sampling by EPA indicated high chloroform and
bromodichioromethane levels in the drinking water at Huron, South Dakota.
Initial work was begun to more precisely define the problem and to suggest
ways of obtaining lower haloforni concentrations. This earlier work is
reported in a document available from EPA (2). The results and recommenda-
tions are repeated as they were the basis for the additional experimentation
reported in this document.
Results
Samples were collected routinely from seven sampling locations within
the water treatment facility and monitored for the THM. Some additional
samples were taken from the distribUtion system. The treatment facility used
lime for softening. Changing the location of the prechlorine dose resulted
in a substantial reduction in haloform concentrations in the product water.
Briefly, the work showed that:
(1) Haloforms form in high concentrations at the point of chlorination
and lime addition.
(2) A 75% reduction in chloroform in the finished effluent was
obtained by changing the point of chlorination from before the
flocculation basins to the recarbonation basin.
(3) Chloroform formation is proportional to pH. However, trying to
lower the pH for chloroform reduction resulted in water instabil-
ity if decreased below a pH of nine.
(4) THM concentrations increase after entering the distribution
system.
(5) Bromodichloromethane formation is not as pH dependent as chloro-
form.
Reconinendati ons
Recommendations which evolved from the study were:
(1) The disinfection should continue at the revised location.
5
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(2) Additional data on bromodichloromethane formation should be
gathered. This constituent was not significantly reduced.
(3) Additional work should be done on the aftergrowth of haloforms
within the distribution system.
(4) Identification of the precursor source(s) should be considered
in an attempt to reduce the potential for chlorinated hydro-
carbon formation. Possibilities to be evaluated should include:
a. point sources upstream
b. the local practice of disposing of dead animals in
the stream
c. precursor increase from biological growth in stagnant
water
d. agricultural runoff as a precursor source
(5) Alternate methods of disinfection should be considered such as
the use of ozone, chioramines and chlorine dioxide.
6
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SECTION 5
WATER TREATMENT AT HURON
History
Huron, South Dakota is located in the east central quarter of South
Dakota. The surrounding terrain is relatively flat. In some places the
James River is above the surrounding area. Therefore, during high flows,
the area adjacent to the James River is flooded, and recedes through infil-
tration, or flows to a drainage basin which runs into the James. This river
is a slow meandering river with depths ranging from one foot to twenty feet,
and alternates between narrow to very wide in the fifteen miles from the
James Diversion Dam to the raw water intake at Huron. A 27 year history of
the James River reveals that there is zero flow about 40 percent of the time,
that 75 percent of the time the flow is less than 30 cf s, and that the mean
annual flow is 259 cfs (3).
The first public water supply for the town of Huron was the James
River. In 1883, water was pumped directly from the James River into the
distribution system without any treatment. In 1886, artesian water was dis-
covered in the Dakota Sandstone at depths of nine hundred feet to eleven
hundred feet. The city discontinued use of the James at this time and
developed four wells which produced highly mineralized artesian water. In
1914, the city switched back to James River water because the artesian sup-
ply became inadequate to meet the demand (4). A 1.5 MGD treatment plant to
clarify and purify the water was constructed at this time. The capacity was
expanded to 3 MGD in 1928.
The drought in the 1930’s caused the river water supply to fall short
of the demand. Wells were drilled again in the Huron vicinity, but this
water was also highly mineralized. The wellswere put in use in 1934, and
the water was distributed with chlorination being the only water treatment.
These wells, in conjunction with the river supply, were used only sparingly
until 1951, when the wells were again used for a short period of time.
In 1948 and 1949, a new 4.15 MGD water treatment plant was constructed
to treat water for purification, clarification, and softening. The level of
the Third Street Diversion Dam was also raised to facilitate more water
storage (4).
In 1959 and 1960, there was a shortage of James River water, forcing
Huron to start the well fields again to fulfill the water demand. The total
municipal water supply for Huron has been obtained from the James River since
1 961.
7
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In 1964, the Bureau of Reclamation constructed the James Diversion Dam,
located about fifteen miles north of Huron. This dam replaced the old Spink
County Reservoir, providing additional storage for Huron’s water supply.
Since the completion of this dam, the well fields have been abandoned and
pumping and other equipment disconnected (4).
The most recent modification to the water treatment plant was finished
in December of 1977. Extensive revisions were made which increased the plant
capacity to 7.4 MGD.
James River Water Quality
The water quality is extremely variable as shown in Table 1. Agricul-
tural runoff, upstream wastewater discharges, dead animals disposed in the
stream, and seasonal variations all combine to make the raw water difficult
to treat for domestic use. According to the operator’s log at the treatment
plant, the river water pH usually falls within a range of from 7.5 to 8.5.
TABLE 1. JAMES RIVER WATER QUALITY
(4 !
Constituent
Raw Water
Low
High
Average
Total solids, ppm
271
2180
547
Total hardness, ppm
131
963
256
Iron, ppm
0.02
0.05
-
Calcium, ppm
53
158
-
Chloride, ppm
51
157
-
Sulphates, ppm
100
785
167
Bicarbonates, ppm
98
812
248
Fluorides, ppm
0.3
0.4
-
Nitrates, ppm NO 3
0.3
2.0
-
Magnesium, ppm
33
119
-
Sodium, ppm
29
352
80
Potassium, ppm
14
25
-
8
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Treatment Process of the 1949 Plant
In the old treatment plant at Huron, water treatment consisted of
chemical addition, sedimentation, flocculation, clarification, recarbonation,
filtration and chlorination. A schematic drawing of the old plant is shown
in Figure 1 and a process description follows:
Process Description
River to plant Raw water is pumped from the James
River at an intake located about one
hundred feet upstream from the Third
Street Diversion Dam.
Initial chemical addition Potassium permanganate, activated
carbon, alum, and a polyelectrolyte
(Nalco 607) are dispersed in the
water.
Presedimentation Settling of one hour duration at a
flow of 6 MGD.
Rapid mix Dispersion of lime, soda ash (occa-
sionally) and sodium aluminate
(Nalco 617) in a rapid mix basin.
Flocculation Gentle stirring of the water-
chemical mixture. Detention time
at 6 MGD is about 1.5 hours.
Clarification Settling of solids with a detention
time of 2 hours at 6 MGD.
Recarbonation Adjustment of pH with carbon dioxide
to obtain stable water. Fluoride,
and polyphosphate (Nalco 918) are
added at this basin.
Prechiorination Initial dose of chlorine for longer
filter runs.
Gravity filters Anthrafilt filtering media used for
filtration.
Postchlorination A final chlorine dose for disinfec-
tion in clear well and distribution
system.
Clear well storage Temporary storage of the finished
water before entering the distribu-
tion system and high level storage.
9
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KMnO 4
ALUM
CARBON
CHLORINE PRIOR
TO 4/76
CHLORINE FLUORIDE
AFTER 4/79 POLYPHOSPHATE
CO 2
RECARBONATION
TO STORAGE
AND CITY
250,000
GALLONS
CLEAR WELL
Figure 1.
Process flow diagram
December 1977.
for water treatment at Huron prior to
j(Th
Th-,
RIVER
POLYE LECTROLYTE
PRESEDIMENTATION
SEDIMENTATION
4
FLOCCULATION RAPID
MIX NO.1
POSTCHLORINATION
1
ANTH RAFILT
I-
GRAVITY
FILTERS
10
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Some typical feed rates for the aforementioned chemicals in the old
plant are given in Table 2. These feed rates vary from day to day. The feed
rates depend on the quality of the raw water and the plant operation.
TABLE 2. TYPICAL CHEMICAL FEED RATES AT WATER PLANT
PRIOR TO DECEMBER 1977*
CHEMICAL
FEED
RATE (pp
m)
9/8/75
5/24/76
Powdered Activated Carbon
2.2
28.0
Potassium Permanganate
0.98
9.37
Alum
29.0
22.0
Polyelectrolyte (Nalco 607)
0.80
0.98
Prechiorine Dose
6.8
4.0
Lime
152.0
135.0
Sodium Aluminate (Nalco 617)
9.6
6.2
Soda Ash
0
0
Carbon Dioxide
36.0
47.0
Fluoride
1.2
1.2
Polyphosphate (Nalco 918)
2.0
1.75
Postchlorine Dose
2.6
4.0
*Operator’s Log, Huron Water Works
Treatment Process of the 1978 Plant
Along with the increase in capacity which was attained by various modi-
fications, some changes in the unit processes were also made. The major
changes were the addition of more presedimentation units; and the combining
of the mixing, flocculation, and sedimentation functions into two solids
upflow basins. Other changes included converting the existing flocculation
tanks to recarbonation and chlorine contact units, new chlorination and
chemical handling equipment, and additional chemical storage area. A schema-
tic drawing of the new plant is shown as Figure 2. A process description is
as follows:
11
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KMnO 4 , POLYELECTROLYTE
CARBON, ALUM
PUMPS
JAMES RIVER RAPID MIX
LIME
SODA ASH
SODIUM ALUMINATE
—a
N)
PRESED I ME NTAT ION
SOLIDS CONTACT
BASIN
CHLORINE CONTACT
CHAMBER
tC 12
REC A RB ON AT ION
TO STORAGE and DISTRIBUTION
Figure 2. Process flow diagram for water treatment at Huron after December 1977.
-------
Process Description
River to plant Raw water is pumped from the James
River at an intake located about
one hundred feet upstream from the
Third Street Diversion Dam.
Initial chemical addition Potassium permanganate, activated
carbon, alum, and a polyelectrolyte
(Nalco 607) are dispersed by mixing.
Presedimentat-jon Settling of from one hour to almost
four hours duration.
Chemical addition Lime, soda ash (occasionally) and
sodium aluminate (Nalco 617) are
added to the center of the upflow
ba s i n.
Upflow basin Solids are settled further and
filtered through a sludge blanket
approximately six feet above the
floor of the tank. Detention time
in this tank is approximately 0.76
hours at 6 MGD.
Recarbonation basin Adjustment of pH with carbon diox-
I d e to obtain stable water. Fluo-
ride, polyphosphate (Nalco 918) are
added at this basin.
Prechlorjne Initial chlorine dose to lengthen
filter runs.
Chlorine contact tank Provides time for the chlorine to
come in contact with the water
before filtration. Detention time
is about 0.66 hours at 6 MGD.
Gravity filters Anthrafilt filtering media used for
filtration.
Post chlorination A final chlorine dose for disinfec-
tion in the clear well and distri-
bution system.
Clear well Temporary storage of finished water
before entering the distribution
system and high level storage.
The flow diagram shown in Figure 2 was followed after December 1977
except for the following instances:
13
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(1) During initial start—up, until February 17, 1978, the recarbonation
and chlorine contact basins were by-passed and the water flowed
directly to the filters.
(2) Sometime near the beginning of April, the carbon dioxide was
inadvertantly applied just prior to filtration, after the pre-
chlorine dose. This resulted in high THM concentrations, and the
recarbonation was corrected on April 30, 1978.
(3) Intentional modification of the disinfection process was made by
the addition of amonium sulfate in May of 1978. This is described
completely in a subsequent section.
Typical chemical feed rates for the new plant are given in Table 3.
TABLE 3. CHEMICAL FEED RATE (TYPICAL) AT WATER PLANT AFTER DECEMBER 1977
FEED RATE (mg/i)
CHEMICAL 2/28/78
Powdered Activated Carbon 15
Potassium Permanganate 3.28
Alum 35*
Polyelectrolyte (Nalco 607) 1.93
Lime 473
Sodium Aluminate 6.21
Soda Ash 76.2
Carbon Dioxide 40.4
Prechiorine Dose 4.62
Fluoride 1.2
Polyphosphate (Nalco 918) unknown dose
Postchlorine Dose 9.56
*No alum is added unless turbidity exceeds 2 Jackson Candle Units. This
is an approximate dosage.
14
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SECTION 6
EXPERIMENTAL METHODS
General
Sample collection and analysis began on May 2, 1977 and continued
through May 10, 1978. This time frame included stagnant summer conditions
in the James River, fall and spring runoff, and stagnant conditions during
the winter months. Therefore, the data presented in this report reflects
the seasonal changes in the James River water quality.
The laboratory tests performed in this study may be grouped into three
areas, i.e., (1) chemical-physical parameters of water quality, (2) tn-
halomethanes concentrations, and (3) biological activity. Chemical-
Physical parameters which were routinely monitored are indicated in Table
4. Trihalomethanes (THMS) monitored consisted mainly of chloroform and
bromodichloroniethane. Due to their low concentrations, other THMs were of
minor concern and were not generally determined.
The following laboratories were used for the testing of the Huron water
samples. Field tests were conducted by the field engineer, at the water
treatment plant at Huron, South Dakota. The THM determinations were per-
formed in the Instrumental Analysis Laboratory in the Chemistry Building at
SDSM&T. Three sets of total organic carbon samples were analyzed by EPA at
the Municipal Environmental Research Laboratory, Cincinatti, Ohio and one
set was analyzed by Dr. Robert Hoehn’s laboratory at Virginia Polytechnic
Institute and State University. Total plate counts and all work using
Salmonella organisms were performed by Dr. Paul Middaugh at South Dakota
State University. The remainder of the chemical-physical and biological
tests were conducted in the Sanitary Engineering Laboratory in the Civil-
Mechanical Engineering Building on the SDSM&T campus.
Field
Sampling stations . Sampling stations were carefully selected through-
out the Huron treatment plant and distribution system in order to follow
the progress of the treatment process and the effect of detention time in the
distribution system. The location of the sampling sites within the treat-
ment plant are indicated in Figures 1 and 2, and are as follows:
Station No. Description
Station 1 - Raw water intake to treatment plant
15
-------
Station No .
Description
Station 2
Station 3
- Effluent from presedimentation tank
- Effluent from rapid mixer
Station 4
- Effluent from flocculation tank
Station 5
Station 5.5N
Station 6
- Effluent from sedimentation tank
- Effluent from recarbonation basin
- Above gravity filters
Station 6.5 - Effluent from gravity filters and
before post-chlorination
Station 7 - Clear well
Six sampling sites within the distribution system (see Fig.
selected such that the residence time varied from a few hours to
The samples collected from these sites were used to measure the
THM concentration in the distribution system and to monitor the
effectiveness of combined chlorine. The following sampling sites were
selected; they are listed in approximate order from shortest to longest
residence time.
Sampling Location Description
a. Masonic Building - centralized, short detention
time
c. Drive-in Liquor-West Side - long detention time
d. Country Kitchen-South Side - long detention time
e. Airport-North Side - extremely long detention time
Sample Handling . The THM samples were collected and sealed bubble free
in 60 ml glass bottles, previously cleaned and heated at 450°C. Samples
from the distribution system were dechlorinated with sodium thiosulfate at
the time of collection and were stored in ice or in a refrigerator until
analyzed. Sample collection and handling procedures for the THM determina-
tions were in close agreement with those used in the NORS (1).
The
analyzed
required
raw water samples collected for the physical-chemical tests were
within two days. No preservation other than refrigeration was
except for the ammonia sample. This sample was preserved with
3) were
a few days.
increase in
disinfection
b. 9th Street Standard
Gas Station/A&M Radio
- centralized, medium detention
time
16
-------
AIRPORT
Figure 3.
Sampling station in the distribution system.
IN LIQUORS
PLANT I I ER
WATER _____
TREATMENT I JAMES
9th ST.
1 A&M RAI IO
COUNTRY
KITCHEN
17
-------
0.8 mg/i concentrated sulfuric acid and was run the day following collection.
All samples were stored in ice, shipped via bus, and then refrigerated at the
laboratory.
Bacteria samples were collected in pre-sterilized “Whirl-pak” bags
(Nasco product). Bacteria samples were always collected while the water
treatment plant was operating. Samples with a hiqh pH were neutralized with-
1 N sulfuric acid; samples containing chlorine were dechlorinated with sodium
thiosuifate. Bacteria samples were stored on ice and shipped by air freight.
The coliform tests were always run within twenty-four hours and usually
within sixteen hours after being collected in Huron.
Field Tests . Chlorine residual (free and total), temperature, and pH
were determined in Huron by the field engineer. Chlorine was determined by
a DPD field HACH kit and pH was determined by a pH meter. When it was
necessary to artificially chlorinate or ammoniate in the field, standard
solutions were shipped to the field engineer from the South Dakota School of
Mines laboratory.
Laboratory
Reagents . All solutions and standards were prepared, when possible,
from reagent grade chemicals. Chlorine demand free water was prepared
according to ‘ t Standard Methods” (5). Chlorine water was prepared in the
laboratory by diffusing chlorine gas in chlorine demand free water for
approximately one minute. Measurements of the actual concentrations were
made following appropriate dilutions with chlorine demand free water.
Organic free water was prepared by purging distilled water at 20 mi/mm
for 11 minutes with helium.
Analytical Procedures . Bacterial determinations of total and fecal
coliforms were performed by the membrane filter technique as described in
“Standard Methods”, Sections 909A and 909C respectively (5).
All 11*1 determinations were performed by the purge and trap technique
described by Bellar & Lichtenberg (6). A Varian Aerograph 705 Gas Chroma-
trograph, equipped with a modified inlet system, a Tractor Model 310 Hall
Electrolytic Conductivity Detector and a Varian A-25 Strip Chart Recorder
were utilized in the determinations. Detailed instrumental parameters are
reported in previous work (2).
Prior to analyzing samples on any given day, the trap was conditioned
by placing it in the heated inlet port of the gas chromatograph and flushing
with helium at 20 mi/mm at 180°C for 4 minutes. Following conditioning
of the trap a blank and two standards were generally run in order to calibrate
the instrument. In addition a set of check samples provided by EPA was
acceptably analyzed.
The analytical procedure used throughout the study was as follows:
1. Place the sample bottle in a water bath at 20°C and allow the
temperature to equilibrate.
18
-------
2. Using a 5 cc glass hypodermic syringe, transfer 5 ml of sample to
the purging device.
3. Attach the trap to the exit port of the purging device and purge
the sample for ii mm with helium gas at 20 mi/mm.
4. Transfer the trap to the modified inlet port of the gas chroma-
tograph and backflush (desorb) with helium at 20 mi/mm at 1800 C
for 4 mm.
5. Replace the trap with a plug, quickly raise the column temperature
to 95° C and start the recorder.
6. Following 14 mm at 95° C, program the column temperature at
8° C/mm to 180° C.
7. Following 5 mm at 180° C, reduce the column temperature to 30° C,
or less, and proceed with the next sample.
As indicated in Table 4, the physical-chemical parameter tests were
performed, for the most part, according to procedures in “Standard Methods”
(5). The “In-Plant Chlorine Demand” is defined as the arithmetic difference
between the total chlorine added and the chlorine residual measured at the
time of sampling.
The last four tests listed on Table 4 were devoloped during the course
of the project and are described in detail in the following paragraphs.
So that the reader may better understand the PTHM data, four defini-
tions presented by Stevens and Symons (7) are given below (items one through
four) along with a definition of PTHM, item 5. The four definitions used
by Stevens and Symons are graphically represented in Figure 4. The PTHM
concentration, as used in this report, would have a higher value than the
Term THM concentration. The five definitions are:
(1) Instantaneous THM (Inst THM) concentration - the
initial concentration of THM in water when sampled.
(2) Terminal THM (Term TI-tM) concentration - the con-
centration of TI-tM that occurs when the 11*1 reaction is
terminated, i.e. at the tap.
(3) THM formation potential (THMFP) - measured as the
increase in THM concentration that occurs during the
distribution system or storage period.
THMFP = Term THM - Inst THM. EQN. 1
(4) Total THM (TTHM) concentration - the summation of the
concentrations of the individual trihalomethane species,
reported in either mg/i or micromoles per liter.
19
-------
Figure 4.
4
REMAINDER
of TOTAL
PRECURSOR
(LITTLE
CONSEQUENCE)
THM
FORM AT ION
POTENTIAL
(B-A)
()
0
0
U i
z
I —
U i
0
-j
I
I—
Graphical representation of four trihalomethane parameters, after
Stevens and Symons (7).
TOTAL PRECURSOR)
APPROXIMATION
of
NCENTRATION
in
WATER
TAP
TERMINAL
THM
CONCENTRATION
(CI SAMPLE
STORED (IMPORTANT
APPROPRIATELY) PORTION of
p
CONC.
at TIME
of
SAMPLING
A B
20
-------
TABLE 4. LABORATORY TESTS AND PROCEDURES OF ANALYSIS
Tests
pH
Temperature
Specific Conductance
Ammoni a
Chemical Oxygen Demand
Suspended Solids
Volatile Suspended Solids
Total Residue
Turbidity
Chlorine Demand
In-Plant Chlorine Demand
Potential Trihalomethanes (PTHM)
Chlorine dose - THM Concentration Curve
Pipe Precursor Material Test
In Pipe Precursor Test
Method of Analysis
“Standard Methods” (5-460)
“Standard Methods” (5-125)
“Standard Methods” (5- 71)
“Standard Methods” (5-381)
“Standard Methods” (5-550)
“Standard Methods” (5- 94)
“Standard Methods” (5- 95)
“Standard Methods” (5- 91)
“Standard Methods” (5-132)
“Standard Methods” (5-132)
See following text
See following text
See following text
See following text
See following text
(5) Potential THM (PTHM) - the THM concentration obtained
at optimum conditions of. pH (pH=11), chlorine dose
(20 mg/i), and retention tTme (3 days).
Potential Trihalomethane (PTHM, raw water)
1) Adjust a sample of raw water to pH 11 using NaOH.
2) Half fill two 300 ml BOD bottles with pH 11 raw water and dose
for 20 and 25 mg/i chlorine respectively.
3) Readjust to pH 11 with NaOH, fill bottles with pH 11 raw water,
stopper and mix.
4) Incubate in a 20°C refrigerator for seventy-two hours.
21
-------
5) Collect and dechlorinate THM samples.
6) Measure free and total chlorine in the remaining solution.
7) Measure the THM concentrations.
The PTHM is defined as the THM concentration for a chlorine dose of
20 mg/i. This can be obtained from a straight line graph between the two
chlorine doses and the concentration concurrent with 20 mg/l of chlorine.
For centrifuged PTHM samples, the above procedure was used with the excep-
tion that after Step 1 the raw water is centrifuged for about one-half hour.
THM Concentration vs. Chlorine Dose (raw water).
1) Adjust the pH of a raw water sample to eleven with NaOH.
2) Half fill 300 ml BOO bottles with pH 11 raw water and add increas-
ing dosages (from 0mg/i to 40 mg/i) of free chlorine.
3) Readjust to pH ii with NaOH, fill the bottles with pH 11 raw water,
stopper and mix.
4) Incubate in a 20°C refrigerator for ninety-six hours.
5) Remove and dechlorinate THM samples.
6) Measure the free and total chlorine of the remaining solution.
7) Measure the THM concentrations.
8) Plot chlorine dose vs. THM concentration.
Pipe Material Test
1) Remove deposited material from section of pipe from distribution
system.
2) Prepare a chlorine standard at pH 11.
3) Add varying amounts (e.g. 0 to 1 g) of pipe material to different
300 ml BOD bottles.
4) Fill the BOD bottles with the chlorinated water.
5) Incubate in a 20°C refrigerator for twenty-four hours.
6) Collect and dechlorinate THM samples.
7) Measure free and total chlorine on the remaining solutions.
8) Determine the THM concentrations for an indication of THM Precursors.
22
-------
In Pipe Test
1) Flush a temporarily unused dead end main until the chlorine concen-
tration approaches that of the clear well.
2) Ininediately following flushing, collect a series of samples to
establish baseline growth of THMs.
3) Periodically collect and dechlorinate THM samples from both the
main and the baseline set. Assure that neither reaction is
chlorine limited by measuring free and total chlorine in both pipe
and baseline samples.
4) Measure and compare the IBM concentrations of the pipe and base-
line samples for indication of in-line precursor material.
23
-------
SECTION 7
RESULTS
In meeting the objectives of the study, work was conducted in five major
areas: (1) Problems associated with aftergrowth of THMs in the distribution
system, (2) correlation of THM concentrations with raw water parameters,
(3) correlation of THM concentrations with land use, (4) monitoring of THM
concentrations, and (5) studies of the use of chloramine as a disinfection
agent. Results of each of these areas of study follows.
Distribution System
The general problem of study regarding the distribution system was first
identified in previous work at Huron (2). While modifications in the treat-
ment process resulted in a reduction of the mean chloroform concentration
from 222 to 59 ppb in the plant effluent, conditions within the distribution
system resulted in a chloroform concentration at the consumers tap of about
127 ppb. The question addressed in this study was whether all of this
increase was due to the continued reaction of residual precursors with free
chlorine or whether some of the increase was coming from reactions of free
chlorine with material contained in the pipe deposits within the distribu-
tion system. In other words, is deposited material within the pipes of a
distribution system a precursor for the haloform reaction. While most of
this material is calcium carbonate, the actual composition is likely to be
considerably more complex. Since little work had been reported on the
characterization of these materials, it was felt that the possibility of the
presence of precursors deserved investigation.
Both laboratory and field studies were conducted in an effort to verify
the presence of precursors in pipe deposits. In the first approach, a sec-
tion of pipe from the distribution system was secured and the deposit removed
and studied for THM production. The second approach consisted of a field
study of an unused, dead end section of water main. Details of the proce-
dures used are found on pp. 21-23.
Results of the laboratory studies are shown in Figure 5. As indicated,
the chloroform concentration increased with the amount of pipe material,
which ranged from 0.10 to 1.0 g per 300 ml of solution. The chlorine
dose (3.43 ppm) was approximately the same as in the distribution system,
however, the pH (at 11) was not. While the formation of chloroform in
increasing amounts cannot be directly related to observed increases in the
distribution system the results do verify the presence of precursor material
in the pipe deposit. Whether these precursors are organic species adsorbed
24
-------
PARAMETERS
pH II
TIME 24HR
TEMPERATURE = 20°C
FREE CHLORINE DOSE 3.43 mg/I
I0
PIPE MATERIAL CONCENTRATION, g/l
Figure 5. Potential chloroform concentration from pipe material at a chlorine dose
of 3.43 mg/i.
30
20
.0
0.
0.
z
0
I-
z
U i
C)
z
0
0
0
U-
0
N)
U,
0
-J
z
U i
0
ci
0.2 0.4
0.8 1.0
-------
from the water onto the pipe material, or whether the precursors result from
some sort of growth is not known.
Results of a second, similar laboratory study in which the chlorine dose
was 18.2 ppm and the pipe material ranged from 5.0 to 200 g per 300 ml of
solution are shown in Figure 6. In contrast with the first study, here an
inverse relationship is observed, i.e. the chloroform concentration decreased
as the dose of pipe material was increased. Free and total chlorine deter-
minations on the solutions at the end of the test indicated that all the
reactions were chlorine limited. Just the opposite had been true for the
first study. It is presumed that the decrease in chloroform concentration
with increasing levels of pipe material results from competing reactions for
the chlorine, i.e. non-precursor organics are successfully competing for the
chlorine, leaving progressively less for reaction with the actual precursors.
While these tests did prove the presence of precursors in the pipeline
deposits, the contribution of these precursors to the observed increase in
THM concentrations within the distribution system remained uncertain. Both
the physical characteristics of the pipe deposits and the pH of the solution
were considerably different from actual pipeline conditions. In addition,
results of total organic carbon (bc) determinations (see Table 5) indicated
that the James River was very stagnant. According to Dr. 0. T. Love, Jr.,
these TOC values were reportedly the highest observed for a drinking water
(to that date) by the EPA Municipal Environmental Research Laboratory,
Cincinnati, Ohio. Even the finished water was found to have a TOC value of
1.6 ppm, which could account for the considerable “growth” of THM within the
distribution system.
TABLE 5. TOTAL ORGANIC CARBON CONCENTRATIONS ON FEB. 14, 1978
Location
Total Organic Carbon, mg/i
Raw Waters
21.81
Clear Well
1.58
Airport
1.81
Following the laboratory test, a field study was conducted in an attempt
to evaluate the actual contribution of the pipeline precursors. The test
developed and performed was referred to as the “In Pipe Test” and is out-
lined on p 23. The test was designed to compare the “growth” of chloroform
in a quarter mile dead end main at Huron with baseline samples collected from
the same main but free of pipe deposits.
The main selected for study had been idle for several months and pre-
sented a number of problems. Even with prolonged flushing, the baseline
samples contained some deposits. In addition the pipeline was depleted of
chlorine within 48 hours indicating the presence of considerable oxidizable
26
-------
0 50 10.0 15.0 20.0
PIPE MATERIAL CONCENTRATION, g/l
Figure 6.
Potential chloroform concentration from pipe material
at a chlorine dose of 18.2 mg/i.
PARAMETERS
pH II
TIME 24 HR
TEMPERATURE 20°C
FREE CHLORINE DOSE 18.2 mg/I
120
100
80
60
40
.0
a.
0 .
z
0
I .-
z
w
0
z
0
0
0
L i-
0
0:
0
-j
0
-J
I—
z
w
I—
0
°20
0
27
-------
material. Within the 48 hours the baseline samples were found to be slightly
higher in chloroform concentrations than the corresponding pipeline s niples.
This was likely due both to the greater chlorine residuals of the baseline
samples as well as to competing reactions for the chlorine within the pipe-
line (similar to those observed for the chlorine limited laboratory test).
Such reactions are certainly suggested by the rapid depletion of the chlorine
relative to the baseline samples.
Due to the problems encountered in the first series of tests, the study
was repeated following a period of time during which the line was put back
in service and allowed to stabilize. An attempt was made to reschedule the
study at a time when the residual chlorine level was relatively high. In
spite of these preparations, the chlorine residual was again depleted within
48 hours. This time no significant difference was observed between the
chloroform concentration of the pipeline and baseline samples. Thus, while
the experimental conditions were far from ideal, leaving a number of ques-
tions unanswered, it would appear that the contribution from the pipeline
precursors is minimal in comparison with that of the residual precursors in
the water itself. This may not be the case with all distribution systems.
Raw Water Parameters
Because of the low levels and complex nature of the THM precursors, it
is difficult to directly determine their concentration and corresponding
potential for 1MM formation. Potential 1MM determinations require the use of
fairly complex instrumentation, skilled laboratory personnel and considerable
time. Some work has been reported on attempts to relate certain raw water
parameters to the potential for THM formation. Such correlations not only
provide a simpler means of monitoring potential THM levels, but can also
provide insight into the source of the precursors. Throughout the course of
the project a number of raw water parameters were monitored and evaluated for
correlation with observed 1MM concentrations. The parameters monitored
included pH, temperature, specific conductance, chemical oxygen demand, total
residual suspended solids, volatile suspended solids, amonia, turbidity and
chlorine demand.
During the course of the monitoring, the Huron treatment plant underwent
a number of changes as their new plant was put into operation. These changes
were often reflected in the THM levels and as such complicated the efforts of
finding correlations with raw water parameters. Stagnant river conditions
and low river flow (reflecting the previous years drought) further compli-
cated these efforts. These factors were undoubtedly responsible for much of
the poor correlation observed for most of the parameters studied.
In order to correlate raw water parameters with THM formation, a new
test was devised to measure what was termed “potential trihalomethanes”
(PTHM). The details of the procedure for this test are presented on p. 22.
Basically the test was designed to evaluate the concentration of TFIMs that
could result from treatment (of the test water) at prescribed conditions of
pH and chlorine does. A pH of 11, approximating that of lime softened water,
was selected. Incubations were for 72 hours at 20°C. It was desirable that
28
-------
the reaction not be chlorine limited, i.e. that the results reflect a total
potential THM concentration. In order to select an appropriate chlorine dose
for such a test it was first necessary to evaluate the effect of chlorine
dose on the THM production of a representative sample. Initial test were
found to be chlorine limited and resulted in THM levels which were directly
proportional to the chlorine dose. This emphasized the importance of
assuring that the chlorine dose be in excess, for each time a set of samples
was collected for the study of raw water parameters, it was necessary to pre-
pare fresh chlorine water and the concentrations of these solutions varied
somewhat. Fig. 7 gives the results of a test in which conditions varied from
chlorine limited to precursor limited. Here the THM concentrations increase
with chlorine dose up to a point and then level off. This allows selection
of the minimum chlorine dose to assure an excess of chlorine. Fig. 7 also
indicates that THM concentrations are chlorine dependent under chlorine
limiting conditions.
Once a chlorine dose had been selected, correlation between THM levels
and raw water parameters were studied. Of these parameters only temperature,
specific conductance and turbidity showed good correlation.
Temperature . The effect of temperature, a parameter known to affect THM
production, is shown in Fig. 8. Much of the scattering of points is presumed
to be due to uncontrolled variations in other parameters which affect THM
formation. Laboratory studies on the affect of temperature on THM growth
curves indicate that while the rate of formation is proportional to tempera-
ture, given sufficient time, (36-48 hours) the final concentrations will be
approximately the same. Fig. 9 shows this effect.
Specific Conductance . Good correlation was observed between specific
conductance and potential chloroform levels. The results, as shown in Fig.
10, indicate that the potential chloroform concentration increases with
increasing specific conductance. This indicates that a good portion of the
precursors are in solution in an ionic state, as-would be expected for humic
acid type substance. This is also in agreement with results of growth curve
studies which indicate that THM concentrations do not increase linearly with
pH, but rather that there is a pH above which THM formation is significantly
enhanced (see Fig. 11). This suggest the,p resence of ionizable acidic
groups within the precursor molecules. Potentiometric titration curves
generated on these solutions do not show any sharp breaks reflecting the
specific pK values of the substances. This is not surprising in light of
the complex nature of these compounds which undoubtedly vary considerably
in their individual pK values.
Turbidity . A good correlation was also found between turbidity and PTHM
levels. As indicated in Fig. 12, the more turbid the water the greater
the THM concentrations. Since components of turbidity include finely divided
organics, plankton and other organisms, either these, or their degradation
products, must be precursors. While turbidity does not directly measure
fulvic acid, it may do so indirectly since it is a degradation produce of
plant material which does contribute to turbidity. No data was collected to
correlate turbidity and natural color to supportthis possibility.
29
-------
Q CHLOROFORM
PARAMETERS
pH II
TIME 96 HR
TEMPERATURE 20°C
RAW WATER
V BROMODICHLOROMETHANE
2000
1000-
0- 1
10 20
FREE CHLORINE DOSE - ppm
Figure 7. PluM vs. Chlorine Dose (5/10/78).
V __ - V
V
-a
0.
a.
2
0
.cZ
a:
I—
z
w
C-)
2
0
0
a:
0
0
a:
0
-J
0
-J
I—
2
w
0
a-
0
. 0
a.
a.
z
0
a:
2
w
0
2
0
100 C-’
2
I
I .-
I ii
0
a:
0
-J
0
0
0
0
50a:
-J
I—
2
w
I-
0
a-
0
I —
30
40
30
-------
0.
0.
F-
o
2
2
0
I .-
C ,)
2
0
I—
z
w
0
2
0
0
0
0
-J
0
120
100
80
Figure 8.
B 0
TEMPERATURE ,°C
Effect of raw water temperature on chloroform concen-
tration.
0
0
0
40
Y 3.71 X+23. 14
0
0
0
0
0
0 5 10 15 20
31
-------
CONTACT TIME, HRS
Figure 9. Effect of temperature on CHC1 3 formation at pH 11.
800
200 C
-o
0.
0.
z
0
I-
z
U i
0
z
0
0
0
(A)
N)
400
200
0
12 24 36
-------
600
500
0
Q.
a.
z
0
w
0
0
0
0
U-
0
0
-J
0
-J
z
UJ
0
0
Y .085 X + 191.04
0
IO
0
Figure 10.
0 1000 2000 3000 4000
SPECIFIC CONDUCTANCE, p.mhos/cm 25°C
Specific conductance as an indicator of potential
chi oroform concentration.
33
-------
200
0
CONTACT TiME, HRS.
Figure 11. Effect of time and pH on CHC1 3 formation at 20°C.
800
pH fl
0
0
600
0
I .-
z
U i
0
z
0
0
400
9
0
12
36
-------
-Q
Q.
0
z
0
I —
U i
C-)
0
0
0
0
0
-J
0
-J
U I
0
Figure 12.
Turbidity as
0
0
0
0
400
30(
0
Y= 9.686 X+259.OI
0
0 10 20 30 40
TURBIDITY , UNITS
an indicator of chloroform concentration.
35
-------
Land Use . The James River was a stagnant pool of water for most of this
study. Flow was recorded during the last three months of the year that moni-
toring was conducted. While this severly curtailed land use studies, a study
was made along a twenty-eight mile section of the river starting at the James
Diversion Dam north of Huron. Samples were collected at key locations along
the 28 mile span and studied for potential THM formation.
Results of the survey are presented in Fig. 13. As indicated the poten-
tial chloroform concentration varied from a low of 706 ppb to a high of 3300
ppb. The high concentrations reflected the stagnant conditions of the river.
In addition the samples were overdosed with chlorine which drove the reaction
to the extreme.
It can be noticed from Fig. 13 that the chloroform level reaches a peak
about 15 miles upstream from Huron and then decreases. Some of these values
seem unreasonably high. However, there is no known analytical reason for
disregarding these data. All samples were treated the same and the results
do reflect differences in water quality at the sampling sites.
When comparing land use to potential chloroform concentration, three
general trends were observed. Peak concentrations seemed to occur where
marsh flow ran into the river, where cattle were watering along the river
bank, and where the river was very broad and shallow.
It was not surprising to find a high potential for chloroform forma-
tion in the marsh areas since these are an excellent source of fulvic and
humic acid substances. To test this theory an oxbow marsh south of Huron
Colony, S.D., was located and tested. The potential chloroform concentra-
tion of this sample was 27% higher than samples from the James River.
High chloroform potential was also found in locations where cattle
watered. While this increase would be mainly due to precursors from the
cattle excretions, a second factor could be the stirring up of the river bed
with the release of degraded plant material.
The increase in potential chloroform concentrations at the location
where the river was very shallow could have several explanations. The biota
could well be quite different, e.g. reflecting a higher temperature;
organics could be easily released from the river bottom under windy condi-
tions, such as were present at the time of sampling; and finally there were
cattle tracks present, suggesting contamination by cattle.
Seasonal Variations . Also considered in the context of land use were
seasonal variations. Of particular interest was the effect of agricultural
runoff which would bereflected in seasonal trends. Municipal discharges,
however, would be diluted by high runoff.
As previously mentioned, this study began during a period of drought.
There was no flow in the James River from October, 1977 to March, 1978.
During this time little change was observed in the PTHM levels. By March 10,
1978, spring runoff sustained flow in the river and the PTHM levels began to
increase. The monitoring data are sumarized in Fig. 14. The substantial
36
-------
0.
z
0
3000 .
F—
z
w
0
z
0
0
(A) 2000
0
0
0
-J
z
1000.
F-
z
w
F—
0
0
tO 15 20
RIVER MILES FROM JAMES DIVERSION DAM
Figure 13. Potential chloroform formation within the James River.
U)
o
-j
I
C,)
w w
F- I-
F- I-
0 0
0 5
25
-------
600
/
V AVERAGE OF ALL DISTRIBUTION SYSTEM STATIONS
O STATION NO. 7 (
500 , POTENTIAL CHCI 3 STA. I
I
400 /
—-— \
3O0 \
\I
200
100
O
o iiii
TIME of YEAR, MONTH/DAY (1977-1978)
Figure 14. Variation of chloroform concentration.
LA)
0.
0.
z
0
I —
I-
z
w
C.,
z
0
0
0
U-.
0
c x
0
-J
T
0
‘V
(2/I I/I 2/I 3/I 4/I 5/I
-------
increase in THM concentrations following the spring runoff supports the
theory that organic precursors are leached from the soil during periods of
heavy rainfall and runoff. High flow rates could also stir up organics from
the river bed which could also account for the increases observed.
Interestingly, the concentration of bromodichloromethane (BDCM),
decreased as the flow rate increased. Data are summarized in Fig. 15. The
decrease in BDCM concentration began following March 10, the day flow began
in the river, and reached a minimum on April 4, the day on which maximum flow
was recorded. This indicates that agricultural runoff is not a significant
source of bromide. On the other hand, bromide from other sources, such as
municipal discharges, would be diluted by the runoff.
Monitoring Trihalomethanes
Throughout the duration of the project, THM concentrations were moni-
tored both in the water treatment plant and in the distribution system.
(Complete data for the monitoring are contained in the Appendix). Results
of previous work at Huron (2) had indicated the importance of pH and there-
fore the significance of the location of the point of prechlorination. At
the start of the current project, prechlorination was still positioned at the
recarbonation basin, to which it had been moved during the previous work.
Chloroform concentrations in the plant effluent (clearwell) were at about
40 ppb. In August prechlorination was moved back to station 3, the point of
lime addition and maximum pH. The change was made in an attempt to combat
taste and odor problems that were being encountered in treating the stagnant
water supply. Following the change, THM were observed at stations 3 through
7. Slight increases at station 7 reflected postchlorination.
The point of prechlorination was returned to the recarbonation basin on
start-up and samples collected on February 27, 1978 showed a significant
reduction in CHC1 throughout the treatment plant. While the plant effluent
levels were reduc d, concentrations in the distribution system remained rela-
tively unchanged. Figures 14 and 15 summarize the data for both the plant
effluent and the distribution system.
Disinfection with pH
It is well known that microorganisms prefer a certain pH range for
growth. Consequently exposure to an adverse pH can result in the destruc-
tion of the cell. Most bacteria have an optimum growth rate near pH 7, and
do not tolerate high pH values for extended periods of time (See Table 6).
The water softening process at Huron uses lime which results in a pH
near eleven for a period of about 3.5 hours. Because alternate methods of
disinfection were being considered, especially the use of combined chlorine,
it became important to better define the disinfection which occurred as a
result of the conventional water treatment processes, including lime
softening. Disinfection which occurs at high pH levels may or may not
39
-------
o Station No. 7
V Average of all Distribution System Stations
TIME of YEAR,MONTH/DAY (1977-1978)
Variation of bromodichioromethane concentration.
z
0
z
w
0
z
0
0
w
z
4
=
u- I
0
0
-J
=
0
0
0
100.
75
50.
25-
0
/
0 lI/I
12/ I I/ I 2/I
3/I
—I
4/I
5/I
Figure 15.
-------
TABLE 6. OPTIMUM pH RANGES FOR SOME COMMON BACTERIA (16)
Bacteria
Minimum pH
Growth Range
Maximum pH
Escherichia coli
4.4
6.0-7.0
9.0
Salmonella typhose
4.5
6.5-7.2
8.0
Corynebacterium
6.0
5.8
7.3-7.6
6.8-7.4
8.3
8.2
diphtheri ae
Neisseri gonorrhoeae
qualify as a primary disinfectant as defined by EPA (8) in the proposed amend-
ment to the drinking water regulations. If adopted as proposed, the regula-
tions would not allow the use of combined chlorine unless another primary
disinfectant had already been used. The amendment also states that: “Chlora-
mines shall not be utilized as the primary disinfectant in drinking water.
Chioramines may be added for the purpose of maintenance of an active chlorine
residual in the distribution system only to water that already meets primary
drinking water regulations.”
A laboratory study to determine the effect of pH on total coliforms was
performed in duplicate with a water sample from the presedimentation basin
effluent (Sta. 2). The initial bacterial count averaged 12,700 total coil—
forms/l00 ml. Four different sub-samples were also taken and adjusted to
pH ranges of 8, 9, 10, and 11 respectively. Total coliform tests were run
at 15, 30, 60, 120, and 240 minutes on each sub-sample. These data are pre-
sented in Fig. 16. The data show a general bacterial decrease as the pH
increases, with pH 11 being the most pronounced.
This laboratory study indicated that pH inhibits bacterial survival, and
at the in-plant pH and contact time one could expect complete destruction of
coliforms. To further determine the influence of pH, an in-plant study was
performed for two months. Total coliform samples were taken at the presedi-
mentation basin effluent (station 2N), which is irruiediately before lime
softening. Another sample was taken immediately after lime softening (sta-
tion 5N) and was neutralized at the time of sampling. The difference in bac-
terial counts between station 2N and 5N will show the effect of pH. The data
(see Table 7) shows an average reduction in total coliforms of 93%. The
average detention time (based on a 2750 gpm flow) r d about 1.2 hours at the
resulting high ph during the time these data were collected.
41
-------
-
0
0
U)
0
-J
0
C-,
-J
0
F-
25000-
20000
pH
pH II
15
30 60
TIME, MINUTES
Figure 16. Coliform disinfection by pH.
42
-------
TABLE 7. REDUCTION IN TOTAL COLIFORMS FROM STATION 2N
TO STATION 5N DUE TO LIME SOFTENING
Date
Station 2N
Total Coliform
100 ml!
Station 5N
Total Coliform
100 ml
pH
%
Reduction
2/21/78
15,000
8
10.7
99
2/29/78
400
7
98
3/10/78
273
3/15/78
692
17
11.2
97
3/25/78
116
4
10.6
96
3/28/78
15
0
11.2
100
4/ 4/78
310
23
11.2
92
4/10/78
50
3
11.0
94
4/19/78
330
104
10.3
68
The above results clearly show the effect of high pH on bacterial sur-
vival. It should be noted that fecal coliforms were seldom run on bacteria
samples. One reason is the high turbidity of Huron’s raw water limits the
quantity of sample that can be filtered. If an inadequate amount of water is
filtered, an unrepresentative sample is obtained. Another reason is the
fecal coliform population in the partially processed water is almost zero.
This correlates with the low total coliform counts at these stations.
Four total coliform tests were run over a 1.25 hour period to determine
the uniformity of Huron’s raw water. The tests showed a range of 5,800 -
17,800 total coliforms/lOO ml with an average of 12,625 per 100 ml. The
results indicate an extremely variable water.
On the same day, a similar test was run at Station 5N.
from 10-65 total coliforms/l00 nil with an average of 34 per
indicates a more uniform water because the presedimentation
softening basins allow for mixing. These data also show the
settling and lime softening on bacteria. A 99% reduction in
was obtained.
Values ranged
100 ml. This
basins and
effect of
total coliforms
Two additional laboratory experiments were conducted in duplicate using
two pathogens, Salmonella typhi and Salmonella typhimurium . In the first
experiment, known titers of approximately 100 cells/rnl of each pathogen were
placed in presterilized water from the Huron water treatment plant. The
limed water had a pH of 10.8. After 2 hours contact time the samples were
incubated on BHI agar plates and counted for colonies. Results are shown in
Table 8. Neither of the pathogens were able to survive for even two hours in
the water from the Huron water treatment plant.
In the second experiment, the titer
S. typhi and S. phimurium . Cells were
was raised to
placed in 0%,
1,000 cells/ml of
25%, 50%, 75%, and
43
-------
TABLE 8. INCUBATION
OF 100 CELLS/mI
OF
PATHOGENS
IN
LIMED WATER
Percent
Limed
Water
Dilution
No.
of
Cells/100 ml
S.
Tjp hi
S. Typhimurium
100
1:1
0,
0
0,0
1:10
0,
0
0,0
1:100
0,
0
0, 0
50
1:1
0,
0
0,0
1:10
0,
0
0,0
1:100
0,
0
0, 0
25
1:1
8,
12
11, 0
1:10
1,
0
1,0
1:100
1,
0
1, 0
0
1:1
84,
80
130, 85
100% limed water from Huron and allowed to set for two hours. Double strength
811 1 was added to the samples which were then incubated and confirmed on triple
sugar iron agar slants. Sample results were recorded as positive ( Salmonella
survived) or negative ( Salmonella destroyed). Results indicate that survival
was only possible for either species if the limed water was diluted (See Table
9).
TABLE 9. INCUBATION OF 1,000 CELLS/mi OF PATHOGENS IN LIMED WATER
Percentage of
Limed Water
S. Typhi
S. Typhimurium
S. Typhi
S. Typhimurium
0%
+;+
+;+
-4 -;-
+;-
25%
+;+
+;+
-4-;-
- ;-
50%
—;—
—;—
.
—;—
+;-
75%
-;-
-;-
+;—
-;-
100%
-;-
-;-
-;-
-;-
+ = Growth
- No Growth
44
-------
Results of the bacterial testing with pH as the variable reinforced the
concept of using combined chlorine for disinfection at Huron. It appeared
that most of the micro—organisms were inactivated from the pH used in the
treatment process, and the main purpose of the disinfectant used was to pre-
vent conta iination from occurring after the water entered the distribution
system.
Previous Experience Using Combined Chlorine
Race (9) was the first to use combined chlorine as a disinfectant.
Until that time (1916), chlorination was accomplished by using free chlo-
rine. Race reported that using hypochlorite produced a water without taste
or odor. Combined chlorine use reached a peak between 1929 and 1939 because
of research by McAmis, Lawrence, and Braidech (10) which showed taste and
odor control with combined chlorine. However, Griffin (10) discovered break-
point chlorination in 1939 and soon water treatment plants were changing to
free chlorine for better disinfection.
Several early investigators indicated that free chlorine was a better
disinfectant than combined chlorine. Howerda (10), Butterfield (11), and
Wattle (10) contributed to this work. The consensus was that combined
chlorine required 100 times more detention time than when using free chlorine
or a concentration 25 times that of free chlorine (10).
Clarke etal. (10) in 1962 coniposited and evaluated previous data to
prepare curves of germicidal efficiency of different chlorine residuals (see
Fig. 17). This yielded a common base to compare the disinfection efficien-
cies of free chlorine (HOC1, OCI) and combined chlorine (NH 2 C1).
The difference in germicidal effectiveness between free chlorine and
combined chlorine decreases at higher pH values. At pH 9 and 20°C, slightly
over 97% of the free chlorine is in the OCY ion form. The OCF ion is a
much poorer disinfectant than hypochiorous acid (HOC1). Figure 17 illustrate
that the effectiveness of the OCl ion and monochloramine is similar. In
fact, White (10) states that the chloramines are better cysticidal agents at
pH values of 9 and above. This fact should be remembered when disinfection
effectiveness is discussed, especially at treatment plants where the effluent
pH is about 9. Lime softening plants in the upper midwest frequently have
pH values in this range.
Several advantages of using chioramines for disinfection have been recog-
nized for several years. Those reported by Babbitt (12) include:
(1) Prevention of tastes, especially phenols.
(2) Control of microorganisms in settling basins, filters, and distri-
bution systems because heavier chlorine dosages will not result in
taste problems.
(3) Stronger bactericidal effects than with free chlorine only when
substantial organic matter is present.
45
-------
I0
5
.5
. 1
.05
.01
.005
E
w
z
0
-J
0
Figure 17.
TIME , MINUTES
(99% DESTRUCTIONof E. COLI . at 2-6° C)
Comparison of germicidal efficiency of hypochlorous
acid, hypochiorite ion, and monochioramine, after Clark
etal. (10).
.00I
46
-------
(4) Long residuals for inhibition of after-growths.
(5) Reduction of chlorine requirements.
(6) Adequate dosages for no fear of overdosing.
(7) Freedom from danger, since chioramines are nontoxic.
(8) A high degree of stability.
Disadvantages of disinfection by using combined chlorine are:
(1) Longer detention times for adequate bacterial control than when
free chlorine is used.
(2) Contact time for chlorine and anononia to convert to chioramines.
(3) An initial investment for ammoniation is required.
(4) Maintaining a correct chlorine:ammonia-flitrOgefl ratio to pre-
vent taste and odor problems from dichloramine and trichlora-
mine formation.
(5) Its ineffectiveness against viruses (13).
In 1963, 308 water treatment plants of the 11,590 treatment plants in
the United States reported using chloramines as a disinfectant. This small
percentage reveals that chioramine disinfectant can be effective and reliable.
Some of the major plants still using chioramines are St. Louis, Missouri;
Kansas City, Kansas; Denver, Colorado; and Pueblo, Colorado. Jefferson
Parish in Louisiana has used chioramine disinfectant for the past twenty
years with great success. Bacteriological field samples have been satis-
factory at all times. (Personal communication, N. Brodtman, Supt. Jefferson
Parish Water Treatment Plant).
Chicago (13) recently switched from combined chlorine disinfectant to
free chlorine. Free chlorine resulted in a decrease in coliform density,
but both types of disinfectant met health requirements. The mean coliform
density for combined chlorine was 0.05 organisms/l0O ml compared to 0.03
for free chlorine. More taste and odor complaints were reported when free
chlorine was used. Also reported was the inability of free chlorine to
maintain a chlorine residual throughout Chicago’s 4000 miles of water mains.
Stevens (14) artificially spiked untreated Ohio River water with free
and combined chlorine. At a 72 hour detention time the chlorinated sample
had a total THM concentration of 160 ppb compared to 16 ppb for the combined
chlorine sample. From this experiment, it is assumed THM concentrations
leaving a water treatment plant will be similar to the THM levels reaching
the consumer - if combined chlorine is used. Tuepker (14) showed this
assumption to be correct in a study for the St. Louis County Water Company
where chioramineS are used for disinfection.
47
-------
Ten of the eighty cities sampled in the NORS survey (1) used chioramines.
The sum of the THM s in the chioramine systems ranged from 1 to 81 ppb with
an average of 19 ppb. The total THM range for systems using free chlorine
was 1 to 472 ppb with an average of 72 ppb. The high THFV1 concentrations in
some of the chloramine utilities are a result of free chlorine being added
prior to aniiioniating. For example, the Kansas City Water Works maintains a
free residual for five hours before ammoniating and their total THM concen-
tration was only 34 ppb in the NORS survey. The St. Louis Water Company
softens and chlorinates and allows eight hours before amoniating. Their
five month average chloroform concentration was 49 ppb (14).
It appears that the use of combined chlorine as a disinfectant has some
definite advantages, especially when trying to reduce the total trihalo-
methanes in a drinking water which has a high pH.
Kinetics of Chioramine Formation
The time involved for ammonia-nitrogen and free chlorine to form chlora-
mines is important. As long as free chlorine is available, it has the poten-
tial to form trihalomethanes. The shorter the time that it takes free chlo-
rine to combine with ammonia, the less chance for THM formation.
The formation of monochloramine is thought to occur as follows (15):
NH 3 + HOC1 - NH 2 C1 + H 2 0 EQN 2
OR
NH + OCl -‘- NH 2 C1 + H 2 0 EQN 3
The equilibrium equation for ammonia is
NH 3 +H -÷ NH EQN4
with a high pH favoring the ammonia (NH 3 ). The equilibrium equation for free
chlorine is
HOC1 - OCY + H EQN 5
with a low ph favoring the hypochlorous acid (HOC1). For equation 2 to pro-
ceed a water with a high pH will have the ammonia available but is limited
by the hypochiorous acid to form chloramines. A low pH will have the hypo-
chlorous acid available but is limited by the ammonia. These same conditions
also limit equation 3 for chioramine formation. Moriochloramine is best
formed at a pH of 8.3 with a chlorine: ammonia-nitrogen ratio of 5:1 or
less by weight. Chloramines are about 100% pure dichioramines at pH of 4.5
to 5.5 and at a chlorine: ammonia-nitrogen ratio of 7:1 to 10:1, by weight.
White (10) states the optimum pH for chloramine formation to be 8.3 with
a variance (either way) from this pH which increases the conversion time. He
reports the conversion time for chloramine formation as 0.069 seconds at
pH 8.3. It was not important to verify this information because the time
frame for THM formation is based on minutes instead of seconds for the chlora-
mine formation.
48
-------
Several tests were performed to verify that the formation of chioramines
does not take any appreciable amount of time. At pH 7.2, 99% conversion of
chioramines was accomplished in six minutes; at pH 8.2, 98% conversion in
twelve minutes; and at pH 10.8, 99% conversion in six minutes. It is known
a 0.5 ppm concentration of free chlorine will promote THM formation (15).
Thus a small amount of free chlorine can be a contributing factor for THM
growth.
Simulation of Disinfection with Chioramines
Because the interim regulations from EPA proposed a THM limit of 100 ppb
and would not allow the use of chioramines as a primary disinfectant, a dis-
infection procedure was experimented with which would use free chlorine as
the primary disinfectant followed by chioramines. A tap was installed
beneath the filters and ammonia and chlorine were added to filtered water to
simulate chloramination after normal disinfection with free chlorine. Ten
sample sets were taken over a two month period from beneath the filters
with each set consisting of a dechlorinated sample, a sample spiked with
chlorine, and a sample spiked with chlorine plus ammonia.
The dechlorinated sample was used to see the extent of THM formation
which would occur from the primary disinfection with free chlorine. The
sample which was spiked with chlorine was used to simulate THM concentra-
tions which would be delivered to the consumer if final disinfection was
continued with free chlorine. The remaining sample which was spiked with
both ammonia and chlorine was used to determine what THM concentrations
could be expected if the final chlorine dose was added as chloramines.
These samples were dosed with the same chlorine dose that was being applied
as the final dose at the water treatment plant. They were then allowed to
set for two to eight days prior to testing to simulate detention time in the
distribution system. Results are summarized in Table 10.
The results show a 55% reduction in TTHM concentrations by using chlora-
mines instead of free chlorine. Free chlorine in the first four chlorinated
samples was extremely small and this limited the TI-tM concentration. Data
from the last four sets of samples are somewhat misleading because the opera-
tors unintentionally changed the point of pH adjustment. This allowed the
prechiorine dose to be added at a high pH which increased the THM concen-
tration. Although a 55% reduction in TTHM concentration is significant, a
greater reduction could have been observed if the above conditions would not
have interfered.
The results also show the addition of ammonia did not stop the THM
reaction entirely. A 317% increase in TTHM is observed from the dechlori-
nated to the chioraminated sample. The primary reason is suspected as being
that the ammonia and chlorine were not immediately brought into contact with
each other. The reagents were both added to a bubble-free 60 ml vial with-
out physical mixing.
Throughout this same period of testing, aliquots from the dechlorinated
sample and the chioraminated sample were tested for coliform bacteria. Coli-
49
-------
TABLE 10. RESULTS OF CHLORAMINATION SIMULATION
(1) (2) (3)
Sample plus
Dechlorinated Sample plus Chlorine and Percent Percent
Sample Chlorine Ammonia Reduction, Increase,
Date TTHM (ppb) TTHM (ppb) TTHM (ppb) Col. (2) to (3) Col. (1) to (3)
3/ 3/78 7 68 22 68 314
3/10/78 6 52 15 71 250
3/15/78 8 56 25 55 313
3/17/78 8 58 31 47 388
0
3/25/78 15 106 30 72 200
3/28/78 18 58 28 52 155
4/ 4/78* 15 199 123 38 820
4/10/78* 44 161 70 57 160
4/18/78* 38 102 55 46 145
4/24/78* 14 110 60 45 429
*pre_chlorjnatjon at high pH
-------
forms were not detected in any of the samples. From these results it
appeared that adequate disinfection could be maintained within the distribu-
tion system while meeting EPA proposed regulations.
Start-up Using Combined Chlorine
Because of the initial favorable results regarding disinfection with
chioramines and pH,it was decided to try combined chlorine disinfection at
Huron. The consulting engineer in charge of the treatment plant expansion
would not approve the installation of an ammoniator within the chlorination
room. Financial considerations did not allow for construction of additional
facilities, so it was decided to use dry ammonium sulfate powder as the source
of ammonia. Some preliminary lab work confirmed that this approach was
technically feasible.
A dry chemical feeder was located and used to meter ammonium sulfate
into the effluent of the recarbonation basin (station 5.5N). This location
allowed the mixing to occur hydraulically. The primary disinfectant,
chlorine, was added in the recarbonation basin.
The initial start-up was concerned primarily with operating the ammonium
sulfate feeder, determining chlorine residuals, and measuring the THM formed.
Samples were taken at station 6N (over the filters) and at station 7 (clear
well).
The first series of samples were collected at a 2.9 chlorine to ammonia-
nitrogen ratio by weight (see Table 11). The chlorine dose was 220 pounds per
day of chlorine and thus the feeder was to deliver 360 pounds per day of
ammonium sulfate (76 pounds of ammonia-nitrogen). The instantaneous THM con-
centration was approximately the same as that of samples allowed to set for a
four day period. The minimal increase in THM concentration during the four
days is attributed to having had an excess of ammonia in the water (0.7 ppm
ammonia-nitrogen).
The second series of samples were collected at a 4.5 chlorine to ammonia-
nitrogen ratio by weight. Consequently the ammoniator was reduced to 230
pounds per day of ammonium sulfate (50 pounds of ammonia-nitrogen). The
instantaneous THM concentrations (Table 11) are the same as the 2.9 chlorine:
ammonia-nitrogen ratio by weight; however, because excess ammunia was not
available (less than 0.1 ppm ammonia-nitrogen) the THM concentration does
increase over the four day holding period. An excess ammonia seems to be
needed to maintain the combined chlorine.
The finished water (using ammonia) was tested for taste and odors and
thought to be of better quality than before. The plant superintendent granted
permission to run the plant full-time based on the improvement in taste and
odor, the excellent bacterial results, the decrease in THM concentration,
and the minor increase in cost.
51
-------
TABLE 11. COMPARISON OF TWO DIFFERENT RATIOS OF
CHLORINE TO AMMONIA-NITROGEN
Parameter
2.9 Cl 2 :
1 NH -N
4.5 Cl 2 :
1 NH 3 -N
Chlorine Residual, mg/i
Free
.1
— .2
.1
- .2
Total
4.4
3.6
Ammonia-nitrogen,
mg/i
N
.7
.1
Inst. THM (ppb)
CHC1 3
32
30
CHC1 2 Br
4
4
4 day THM (ppb)
CRC 1
3
36
57
CHC1 2 Br
5
6
Full-Scale Operation with Combined Chlorine
Based on the preliminary work previously discussed, chloramines were
introduced as the final disinfectant dose on a continuous full-scale basis
beginning on May 10, 1978. The initial goal of this phase was to continu-
ously run the plant in this mode for about 15 to 20 days. After this time,
it was expected that the plant operation would revert back to free chlorina-
tion while the results were being analyzed. However, the addition of the
anii onium sulfate resulted in a dramatic increase in the drinking water
quality (taste, odor, and THM concentrations); and the municipal officials
decided to continue the process without interruption, if possible. Con-
sequently, the aninonium sulfate feed rate was decreased toward the end of
May in order to keep the process continuous until additional ammonium sul-
fate could be received at the plant. This decrease in feed rate caused an
increase in the THM concentrations in the distribution system, although the
THM values were still substantially less than before the ammonium sulfate
was used.
It was very critical during the first few days of full-scale operation
to assure that adequate disinfection was occurring. Fifteen samples for
total coliforni testing were taken the first two days, and all test results
52
-------
were negative for coliforms. Samples for total coliform testing were
obtained every three days from within the distribution system. All results
met standards except for two samples at the Country Kitchen.
The two samples at the Country Kitchen had 2 and 6 total coliforms/lOO
ml. These samples were thought to have been contaminated while sampling.
The faucet where the samples were taken was located outside the building
and near some refuse containers. It was a good possibility that air-borne
bacteria may have entered the sterile bag while sampling. Sampling tech-
niques were changed to minimize contamination and all samples thereafter
were negative for total coliforms.
The first few days involved adjusting the ammoniator to an efficient
but economical chlorine to ammonia-nitrogen ratio. Ranges of 4.5, 4.0, 3.5,
and 3.0 parts of chlorine to one part ammonia-nitrogen by weight were chosen.
These ranges are recommended by White (10) to be economical and yet adequate
to form monochloramines without forming the dichloramines which cause taste
and odor.
The four ranges of 4.5, 4.0, 3.5, and 3.0 were tested with samples for
unionized ammonia collected at the effluent of the clear well (station 7).
Results showed 1.3, 1.6, 2.1, and 2.9 mg/l of unionized ammonia-nitrogen,
respectively. This indicated an adequate amount of ammonium sulfate was
being added. Ammonia residuals varied slightly from day to day depending
on the amount of ammonia in the raw water and plant operating conditions.
The major objective of this research was to use chioramines to reduce
the THM concentrations in the plant effluent and at the consumer’s tap. The
five distribution system stations along with station 6 (above the gravity
filters) and station 7 (clear well) were tested for THM on a bi-weekly basis
between August 7, 1977 and until the introduction of chloramines on May 10,
1978. These THM results depict the type of water the consumer was obtaining
with chlorine as the disinfectant. After chloramines were used as the
secondary disinfectant, these same stations were sampled about every three
days until June 3, 1978 to show the reduction in THM concentrations.
Concentrations for chloroform and bromodichioromethane during this
period are given in Table 12. An obvious reduction is noted after the change
over to combined chlorine on May 10, 1978. Trihalomethane values within the
distribution system were generally less than 20 ppb of chloroform and 7 ppb
of bromodichioromethane. The rise in concentrations for the samples of May
27 and June 3 reflect the decrease in ammonium sulfate being added to the
system while additional chemical was awaited. The feed rate was adjusted to
5.5:1 which is greater than the recommended range of from 3-4 mg/i chlorine
to 1 mg/l ammonia. Excess ammonia was not available to keep all of the
chlorine in the combined form, resulting in free chlorine which promoted
THM formation.
A plot of total THM values (numerical addition of CHC1 and CHC1 2 Br con-
contrations) is shown in Figure 18. Samples collected at t e Masonic
53
-------
TABLE
12. TF 4
CONCENTRATIONS
DURING TRANSITION
PERIOD
Sampling
Station
April
4_J8
10
11
12
Sampling
Date
22
June
24 27 3
May
13 15
18
Clear Well
(Sta. 7)
CHCL 3 ,ppb 55 105 17 12 18 11 5 39 44
CHC1 2 Br, ppb 4 9 8 5 7 6 3 5 4
Masonic Bldg.
CHC1 3 ,ppb 113 124 223 62 18 16 7 15 60
CHC1Br,ppb 3 12 50 8 6 5 4 7 4
Ninth St. Standard
CHC1 3 , ppb 128 121 153 87 20 15 8 19 71 37
CHC1 2 Br,ppb 4 14 29 15 7 3 4 6 5 2
Country Kitchen
CHC1 3 ,ppb 134 139 165 62 16 18 7 17 71 47
CHC1 2 Br,ppb 5 10 21 6 6 6 3 4 5 4
Drive-In Liquor
CHC1 3 ,ppb 108 159 172 78 78 19 25 15 20 67 44
CHC1 2 Br,ppb 14 21 19 20 10 7 9 3 12 5 4
Airport
CHC1 3 ppb 298 156 210 121 168 26 12 11 69 66
CHC1 2 Br,ppb 13 17 27 24 15 12 5 4 3 9
-------
MASONIC BUILDING
It
/
, çAIRP0RT
‘H
It
IS 2 2 30
APRIL MAY
/
I/I
\
\
\
-
\
01
01
25O
200
150
100 .
50.
0
Q.
I
-J
0
I —
ON 7
CLEAR WELL
It
I
‘—— -S
I
AMMON IUM
S U L FATE
STARTED—
3 10
JUNE
Figure 18.
THM reduction using ammonium sulfate.
-------
Building reflect the growth that occurs during a medium residence time in the
distribution system. Those samples collected at the airport would be indica-
tive of the growth that occurs during a long residence time. Again, the
effect of the amonium sulfate addition is clearly seen. It would seem that a
total THM concentration at the tap of less than 50 ppb, and probably less
than 25 ppb, should be easily obtainable with this method. The rise in con-
centrations at the end of May, again, is a result of a lowered amonium sul-
fate feed rate.
The reductions in total THM by using chioramines was 37% and 50% at
station 6N (above the filters)and station 7 (clear well), repectively. The
average reduction in the distribution system, neglecting the transition
period, was 75%. The total THM concentration dropped from an average value
of 154 ppb to 37 ppb. The individual reductions at the various distribution
sampling stations are:
Masonic Building——76%
9th Street Standard--75%
Country Kitchen--75%
Drive-in Liquor--72%
Airport--79%
It is believed Huron can maintain the total THM concentration below 30
ppb if:
(1) The pH is kept low at the point of application of chlorine, and
(2) A ratio of 3-4:1 chlorine:amonia-nitrogen is applied.
Operation with Combined Chlorine
A noticeable decrease in the taste and odor of the finished water was
evident to engineers, operators, and the public when the transition was
made to combined chlorine. The raw water at Huron has a high organic content,
sometimes exceeding 20 mg/i of total organic carbon. The finished drinking
water was frequently the source of taste and odor complaints from consumers.
In fact, the taste and odor of the finished water may be an adequate indica-
tor of treatment for the water treatment plant operator. If the chlorine to
aninonium sulfate ratio becomes too high, dichioramines are formed which
result in an off taste to the water. At this point the operator knows that
he needs to check the chemical feed rates and possibly increase the amonium
sulfate feed rate.
The above statement was verified during the sumer of 1978. A spot
check of the operation on June 27, 1978 yielded the information displayed in
Table 13. At this time, some taste and odor problems were evident. The
aninonium sulfate feeder was adjusted with a subsequent decrease in THM
56
-------
concentrations. On July 14 the plant was producing 53 ppb of chloroform and
8 ppb of bromodichioromethane in the finished water (station 7). An increase
of about 15 ppb was obtained for chloroform within the distribution system,
while a change in the bromodichloromethane concentration was not detected.
TABLE 13. THM CONCENTRATIONS ON JUNE 27, 1978
The only ill affect noticed to date of using ammonium sulfate was the
excess anaiionia residual in the tap water. This ammonia residual is not detri-
mental to human health but is harmful to aquatic life (17). Unionized
amoni’a (NH 3 ) should not exceed 0.02 ppm of arwnonia-nitrogen for fish sur-
vival (18). The amount of ammonia in water varies with the pH and tempera-
ture. Table 14 shows the concentrations of ammonia (NH ÷NH 4 +) which contain
an unionized ammonia concentration of 0.02 ppm of ammonia-nitrogen.
TABLE 14. AMMONIA CONCENTRATIONS WHICH RESULT IN
0.2 mg/i UNIONIZED AMMONIA (NH 3 )
Temperature
°C
6.0
pH
7.0
8.0
9.0
10.0
20
51.9
5.20
.539
.072
.025
25
36.3
3.65
.384
.056
.024
30
25.6
2.58
.276
.046
.023
The excess ammonia in Huron’s tap water resulted in some fish kills in
aquariums throughout the city. Aquarium temperatures range from 21° - 27°C
(23°C optimum) and Huron’s pH at the tap ranges from 8.4-9.6. The maximum
contaminant levels of ammonia for these ranges are 0.03 to 0.21 ppm ammonia-
nitrogen (18). Since these low ammonia levels would be almost impossible to
Station
CHC1 3 , ppb
CHC1 2 Br, ppb
Clear Well
65
11
Masonic Building
121
19
Country Kitchen
140
--
At this writing (February 1979) combined chlorine is still providing satis-
factory results. The chlorine residual level is about 3 mg/l at the tap with
only a trace amount (<0.2 mg/i) possibly present as free chlorine.
57
-------
maintain by the plant operators, other solutions were necessary. The excess
aninonia is necessary to reduce THM formation and cannot be controlled and
reduced adequately to meet the maximum contaminant level for fish.
The most realistic solution is to adjust the pH to 7. This allows an
ample margin of safety (See Table 9-9) for fish survival. A pH of 7 is also
the optimum pH for tropical fish survival, growth, and reproduction. Chemi-
cals for pH adjustment are normally available at retail outlets which market
tropical fish.
Total plate counts are sometimes used as a check on the bacterial
quality of a finished drinking water. There is no sanitary significance in
testing for total plate counts. A low total plate count does not indicate a
disinfected water and on the other hand a high total plate count does not
signify a contaminated water. High bacterial counts will sometimes interfere
with the membrane filter technique for testing coliforms.
Total plate counts were performed before and after changing the disin-
fection procedure. Three sets of samples were taken when chlorine was being
used and one set when chioramines were used. The results (Table 15) show
chioramines did not deteriorate the disinfection capabilities of the water
but actually enhance disinfection. Of course, one would expect a high bac-
terial count in October and November and samples with a lesser count during
the spring (April and May). However, a 52% decrease in total plate counts
was obtained from April to May by switching to combined chlorine.
TABLE 15. EFFECT OF CHLORINE VS.CHLORAMINES
ON
TOTAL PLATE
COUNTS
Station
Total Plate Count/mi; Type
of Disinfection
1D/30/77
Chlorine
11/ 6/77
Chlorine
4/ 5/78
Chlorine
5/15/78
Chloramines
#7 (Clear Well)
188
880
111
12
Masonic Bldg.
188
980
139
39
9th Street Standard
149
620
133
119
Drive-in Liquor
1000
5210
126
67
Country Kitchen
219
620
83
111
Airport
6380
6140
121
23
Economics
The addition of amonia will increase the price of water treatment. The
amount of amonia added for treatment is dependent upon the chlorine dose.
The maximum chlorine dose added in 1977-1978 was 840 pounds of chlorine per
58
-------
day. At a 3:1 chlorine:ammonia-nitrogen ration by weight, the maximum cost
of ammoniating (using amonium sulfate) would be about 4 /lOOO gallons at
current prices. The average chemical cost of chloramination was about
2 /l,O0O gallons at Huron during 1978. Currently high-grade ammonium sul-
fate, suitable for drinking water, can be obtained for $O.175 per pound.
One important comparison of chioramines with ozone, chlorine dioxide,
aic GAC is cost. Table 16 shows an estimate of the costs for various dis-
infection alternatives based on a 5 MGD plant. J. M. Symons etal. (14)
compiled these costs and they are based on installing and operating new
facilities with no existing equipment.
TABLE 16. ESTIMATED COSTS OF DISINFECTION ALTERNATIVES FOR A 5 MGD PLANT
Alternative
Cost in t/1OOO gallons
Operating Capital
Total
Chlorine (2ppm)
0.56
0.88
1.44
Ozone (lppm)
1.05
1.36
2.41
Chlorine dioxide
(lppm)
1.18
0.76
1.90
Chloramines (3ppm
)
0.78
0.89
1.67
These data reveal chloramines to be an economical solution to reduce
THM formation. It should be remembered that most plants already have
existing facilities for chlorination and only equipment to add ammonia would
be necessary.
59
-------
REFERENCES
1. Symons, J. M. etal. National Organics Reconnaissance Survey for
Halogenated Organics. Jour. AWWA , 67:11:634 (Nov. 1975).
2. Harms, L. L. & Looyenga, R. W. Formation and Removal of Halogenated
Hydrocarbons in Drinking Water. EPA 908/3-77-001, U.S. Environmental
Protection Agency, Denver, Cob. (Jan. 1977).
3. Sumary Report Water Quality and Return Flow Study, Initial Stage -
Oahe Unit. Missouri-Oahe Projects Office, Huron, S.D. (Sept. 1975).
4. J. T. Banner and Assoc., Inc. “Report on Water Supply System and Pro-
posed Improvements for City of Huron, S. Dak.” Brookings, S.D.
(May 1975).
5. Standard Methods for the Examination of Water and Wastewater. APHA,
AWWA, WPCF, Washington, D.C. (14th ed., 1975).
6. Bellar, 1. A. and Lichtenberg, J. J. Determining Volatile Organics at
Microgram Per Litre Levels by Gas Chromatography. Jour. AWWA ,
66:12:739 (Dec. 1974).
7. Stevens, A. A. & Symons, J. M. Measurement of Trihalomethane and Pre-
cursor Concentration Changes. Jour. AWWA , 69:10:546 (Oct. 1977).
8. Interim Primary Drinking Water Regulations, Control of Organic Chemi-
cal Contaminants in Drinking Water. U.S. Environmental Protection
Agency, Federal Register , Feb. 9, 1978, Part II.
9. Race, J. Chlorination and Chloramines. Jour. AWWA , 5:3:79 (Mar.
1918).
10. White, G. C. Handbook of Chlorination. Van Nostrand Reinhold Co., New
York, N.Y. (1972)
11. Butterfield, C. 1. Bactericidal Properties of Free and Combined Avail-
able Chlorine. Jour. AWWA , 40:12:1305 (Dec. 1948).
12. Babbitt, H. E. etal. Water Supply Engineering. 6th Ed., McGraw Hill
Book Co. New York, N.Y. (1962).
13. Willey, B. F. et al. Chicago’s Switch to Free Chlorine Residual. Jour.
AWWA , 67:8:43S Aug. 1975).
60
-------
REFERENCES (continued )
14. Symons, J. M. etal. Ozone, Chlorine Dioxide, and Chioramines as Alter-
natives to Chlorine for Disinfection of Drinking Water, State-of-the-
Art. U.S. Environmental Protection Agency, Cincinnati, Ohio (Nov.
1977).
15. Cookson, J. 1., and Arguero, R. C. Chlorinated Organics Evolving from
Disinfection Practices - A Review of State of the Art Research.
16. Pelczar, M. J., and Reid, R. D., Microbiology, 3rd ed., McGraw-Hill
Book Co., New York, N.Y. (1972).
17. McKee, J. E., and Wolf, H. W. “Water Quality Criteria.” Publication
3-A, Calif. State Water Quality Control Board, Sacramento, CA (1963).
18. Willingham, W. T. Ammonia Toxicity. EPA 908/3-76-1, U.S. Environmen-
tal Protection Agency, Denver, CO (Feb. 1976).
61
-------
APPENDIX A
FULL PLANT AND DISTRIBUTION SYSTEM DATA
TABLE Al. CHLOROFORM AND BROMODICHLOROMETFIANE CONCENTRATIONS IN RAW WATER —
Date CHC1 3 CHC 1 2 Br
(ppb) (ppb)
7/ 7/77 ND ND
7/ 8/77 ND ND
7/13/77 ND ND
8/ 3/77 ND ND
8/ 6/77 ND ND
8/18/77 ND ND
10/29/77 ND ND
11/15/77 ND ND
11/29/77 ND ND
1/ 4/78 ND ND
1/18/78 ND ND
1/30/78 ND ND
2/13/78 ND ND
ND = Not Detectable
62
-------
TABLE A2. CHLOROFORM AND BROMODICHLOROMETHANE CONCENTRATIONS
FOR STATION NO. 3
Date
CHC1 3
(ppb)
CHC1 2 Br
(ppb)
7/ 7/77
ND
ND
7/ 8/77
ND
ND
7/13/77
ND
ND
8/ 3/77
ND
ND
8/ 6/77
153
< 5
8/18/77
21
ND
10/29/77
81
< 1
11/15/77
62
< 1
11/29/77
78
6
ND = Not Detectable
63
-------
TABLE
A3. DATA ABOVE
GRAVITY FILTERS (STATION
6).
Date pH
Chlorine
(ppm)
CHC1
(ppb3
CHC1 Br
(pp )
Tot.
Coliform
Free
Total
100 ml
7/ 7/77 29 18
7/ 8/77 44 ND
7/13/77 33 31
8/ 3/77 10.2 50 5
8/ 5/77* 9.3 94 5
10f29/77* 9.5 81 1
1V15/77* 9.3 62 4
1V29/77* 9.2 78 5
NEW WATER PLANT START-UP
1/ 4/78 8.9 32 12
1/18/78 9.5 11 7
1/30/78 9.6 5 3
2/13/78 9.5 4 2
3/ 3/78 9.6 4 3
3/13/78 9.3 6 9
3/24/78 9.3 11 7
4/ 4/78* 7 43 2
4/18/78* 8.9 40 4
STARTED AMMONIUM SULFATE
5/10/78 8.6 0.05 0.6 30 9
5/18/78 3 1
5/22/78 9.1 0.3 0.4 3 1
5/24/78 9.2 0.2 1.7 11 1 15
5/26/78 9.2 0.2 1.6 6
5/27/78 9.4 0.3 1.9 62 1 21
5/31/78 9.0 0.1 1.5
6/ 3/78 8.3 0.7 1.6 29 3
NOTE: All samples dechlorinated upon sampling
* Pre-chlorinating at high pH. ND = Not Detectable
64
-------
TABLE A4. DATA AT EFFLUENT OF CLEAR WELL (STATION 7)
Chlorine (ppm ) CHCl. CHC1 2 Br Tot. Coliform
Date pH Free Total (ppb’ (ppb) 100 ml
7/ 7/77 36 ND
7/ 8/77 48 20
7/13/77 38 20
8/ 3/77 9.3 62 5
8/ 5/77* 8.9 63 5
10/29/77* 8.0 86 6
11/15/77* 8.1 66 3
11/29/77* 9.0 42 4
NEW WATER PLANT START-UP
1/ 4/78 8.9 49 22
1/18/78 9.4 54 12
1/30/78 9.0 2.7 3.0 34 11
2/13/78 8.4 >3.0 >3.0 23 6
2/27/78 8.7 >3.0 >3.0 17 8
3 /13/7 8.2 >3.0 >3.0 27 17
3/24/78 7.4 6.4 9.2 26 6
4/ 4/78* 9.5 6.0 10.0 55 4
4/18/78* 8.4 2.1 2.4 105 9
STARTED AMMONIUM SULFATE
5/10/78 8.7 2.8 4.0 17 7 0
5/10/78 0.1 3.7 17 9 0
5/11/78 8.6 0.15 12 5 0
5/12/78 8.2 0.3 6.8 18 7 0
5/12/78 7.8 0.2 5.2 12 3
5/18/78 11 6
5/22/78 8.7 0.1 2.7 5 3
5/24/78 8.6 0.3 2.6 39 5 0
5/27/78 9.4 0.4 3.6 0
5/31/78 8.5 0.3 2.5 0
6/ 3/78 8.6 0.2 2.1 44 4
NOTE: All samples dechlorinated upon sampling
*p _chlorinating at high pH. ND = Not Detectable
65
-------
TABLE A5. DATA AT MASONIC
BUILDING
Chlorine (r pm)
Date pH Free Total
Tot.
Coliform
CHC1 3
(ppb)
CHC1 2 Br
(ppb)
100
ml
7/ 7/77 89 28
7/13/77 102 53
8/ 3/78 9.1 117 88
8/ 5/78 8.7 260 152
8/18/78 119 18
10/29/78* 8.3 116 48
11/15/78* 8.8 134 47
11/29/78* 8.7 92 14
NEW WATER PLANT START-UP
1/ 4/78 9.3 98 19
1/18/78 9.1 1.3 2.0 111 26
1/30/78 9.2 2.1 3.0 81 44
2/13/78 8.7 0.5 1.5 66 52
3/ 3/78 8.2 0.63 1.6 84 47
3/13/78 8.3 0.4 1.1 66 51
3/24/78 7.2 2.9 4.6 83 18
4/ 4/78* 8.1 2.4 4.4 113 3
4/18/78* 8.9 1.9 2.4 124 12
STARTED PJ !40NIUM SULFATE
5/11/78 0.3 1.7 0 223 50
5/12/78 0.3 2.3 0 62 8
5/13/78 0.18 3.2 18 6
5/18/78 16 5
5/22/78 0.4 2.4 7 4
5/24/78 8.5 0 15 7
5/26/78 8.8 0.2 2.2 0
5/27/78 9.3 0.3 2.3 0
5/31/78 9.0 0.3 2.7
6/ 3/78 9.2 0.3 2.7
NOTE: All samples dechlorinated upon sampling
*Pre....chlorjnating at high pH.
66
-------
TABLE A6. DATA AT 9TH STREET STANDARD/A&M RADIO
Chlorine
Date pH Free
(ppm)
Tot. Coliform
CHC1 3
(ppb)
CHC1 2 Br
(ppb)
Total
100
ml
8/18/77 80 28
10/29/77* 8.6 ‘42 56
11/15/77* 9.0 134 40
11/29/77* 8.7 100 38
STARTED NEW WATER PLANT
1/ 4/78 113 21
1/18/78 9.1 1.2 1.9 92 19
1/30/78 9.2 2.2 2.7 80 34
2/13/78 8.7 1.0 1.8 89 55
3/ 3/78 8.2 0.7 1.5 98 51
3/13/78 8.7 0.4 1.0 71 38
3/24/78 7.6 0.3 1.3 72 14
4/ 4/78* 7.7 2.6 3.0 128 4
4/18/78* 9.1 1.8 2.2 121 14
STARTED USING AMMONIUM SULFATE
5/11/78 0.1 1.0 0 153 29
5/12/78 8.7 0.15 1.8 0 87 15
5/15/78 9.1 0.13 3.1 20 7
5/18/78 15 3
5/22/78 8.8 0.5 2.6 8 4
5/24/78 8.4 0.3 1.9 0 19 6
5/26/78 8.8 0.3 2.1 0
5/27/78 9.3 0.4 2.4 0 71 5
5/31/78 9.2 0.2 2.3
6/ 3/78 9.3 0.3 2.6 37 2
NOTE: All samples dechlorinated upon sampling
*p _c orinating at high pH.
67
-------
TABLE A7. DATA AT COUNTRY KITCHEN
NOTE: All samples dechlorinated
*pre_chlorjnating at high
upon sampling
pH.
Date
10/29/77*
Chlorine
pH 1-ree
(ppm) Tot. Colifornis
lotal 100_ml
11/15/77*
11/29/77*
STARTED NEW
8.4
9.0
9.0
WATER PLANT
CHC1
111
CHC1 9 Br
40
9.4
9.1
1.2
2.0
9.1
2.1
2.7
8.6
.9
1.3
8.1
.9
1.2
8.6
.6
.9
7.6
.6
1.0
7.9
2.2
2.8
179
56
102
17
1/ 4/77
124
50
1/18/78
116
31
1/30/78
95
31
2/13/78
78
46
3/ 3/78
89
59
3/13/78
65
55
3/24/78
88
12
4/ 4/78*
134
5
4/18/78*
139
10
STARTED
USING At0IONIUM SULFATE
5/10/78
8.9 0.98 1.5
165
21
5/11/78
1.0 1.5
0
62
6
5/12/78
8.7 0.15 2.3
6
5/15/78
9.1 0.1 3.1
16
6
5/18/78
18
6
5/22/78
8.8 0.4 2.4
7
3
5/24/78
8.8 0.3 1.8
2
17
4
5/26/78
8.7 0.4 2.0
0
5/27/78
9.3 0.3 2.5
0
71
5
5/31/78
9.6 0.3 2.2
6/ 3/78
9.6 0.4 2.5
47
4
68
-------
Chlorine
Date pH Free
(ppm)
Tot. Coliform
CHC1 3
(ppbj
CHC1 9 Br
(ppb7
100
ml
Total
8/18/77 117 62
10/29/77* 8.2 97
11/15/77* 8.9 143 59
11/29/77* 8.7 103 4
STARTED NEW WATER PLANT
1/ 4/78 101 13
1/18/78 8.1 0.1 1.9 107 29
1/30/78 9.2 1.6 2.5 92 39
2/13/78 8.7 0.2 1.2 84 59
3/ 3/78 8.2 0.4 1.2 88 61
3/13/78 8.4 0.2 0.9 67 41
3/24/78 8.8 0.4 1.7 85 12
4/ 4/78* 8.0 2.7 4.4 108 14
4/18/78* 8.8 1.5 1.8 159 21
STARTED USING AMMONIUM SULFATE
5/10/78 9.0 0.8 1.2 172 19
5/11/78 8.9 0.3 1.2 0 78 20
5/12/78 8.7 0.15 2.3 0 78 10
5/15/78 9.0 0.2 3.2 19 7
5/18/78 25 9
5/22/78 8.8 0.5 2.4 15 3
5/24/78 8.8 0.2 2.3 0 20 12
5/26/78 8.7 0.2 2.2 0
5/27/78 9.4 0.4 2.7 0 67 5
5/31/78 9.0 0.2 2.3
6/ 3/78 9.0 0.2 2.1 44 4
NOTE: All samples dechlorinated upon sampling
at high pH.
69
-------
TABLE A9. DATA AT THE AIRPORT
Chlorine (ppm) Tot. Coliform CHC1 3 CHC1 2 Br
Date pH Free Total 100 ml (ppb) (ppb)
7/ 7/77 134 49
7/13/77 84 ND
8/ 3/77 9.7 196 103
8/ 5/77 279 163
8/18/77 113 28
10/29/77* 9.4 154 60
11/15/77* 94 150 42
11/29/77* 9.2 189 42
STARTED NEW WATER PLANT
1/ 4/78 9.4 109 48
1/18/78 9.2 0.4 1.1 181 51
1/30/78 9.2 0 0.7 107 68
2/13/78 9.0 0 0.8 107 63
3/ 3/78 8.3 0.2 1.0 148 88
3/13/78 9.0 0.1 1.4 69 59
3/24/78 7.1 0.1 2.1 79 20
4/ 4/78* 9.0 2.3 3.0 298 13
4/18/78* 9.0 0.8 1.2 156 17
STARTED USING AMMONIUM SULFATE
5/10/78 9.1 0.4 0.95 210 27
5/12/78 9.3 0.85 1.35 0 121 24
5/15/78 9.4 0.1 3.1 168 15
5/18/78 26 12
5/22/78 9.3 0.3 2.6 12 5
5/24/78 9.5 0.2 2.4 0 11 4
5/26/78 8.6 0.2 2.3 0
5/27/78 9.4 0.3 2.2 0 69 3
5/31/78 9.3 0.2 2.2
6/ 3/78 9.4 0.2 2.3 66 9
W TE: All samples dechlorinated upon sampling
*pre. .chlorinatjng at high pH.
ND = Not Detectable
70
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APPENDIX B
RESIDENCE TIME IN THE DISTRIBUTION SYSTEM
TABLE Bi. RESIDENCE TIMES IN THE
Station Starting Chlorine
Residual (ppm)
Free Cl 2 Total Cl 2
DISTRIBUTION SYSTEM, CHLORAMINES STUDY
Final Chlorine Time from
Residual (ppm ) Chloramines
Free Cl 2 Total Cl 2 Introduction
15-18 hours
15-26 hours
4.75 days
Masonic
Building
1.2
2.2
0.3
1.7
A&M Radio
1.2
2.2
0.1
1.0
Drive-in
Liquors
0.8
1.2
0.3
1.2
Country Kitchen
1.0
1.5
0.3
1.8
Airport
0.4
0.9
0.1
3.1
15 hours
15 hours
71
-------
APPENDIX C
PIPE MATERIAL TEST
TABLE CI. PIPE MATERIAL TEST NO. 1
Parameters
Chlorine Demand Free Water
Chlorine Dose (free) 3.43 ppm
pH=l 1
Time=24 hours
Temperature 2O°C
Pipe Material Chlorine Residual PTHM
Added Free Total CHC1 CHC1 Br
(gil) (ppm) (ppm) (ppb (pp )
0.0 2.68 3.18 5 2
0.0 3.45 3.6 5 4
0.1 2.80 2.80 11 5
0.1 3.00 3.00 14 4
0.5 1.35 1.35 19 ND
0.5 1.35 1.5 37 ND
1.0 0.89 0.91 33 4
1.0 0.81 1.00 30 5
5.0 0.03 0.18 19 4
5.0 0.03 0.09 18 6
NDN0t Detectable
72
-------
TABLE C2. PIPE MATERIAL TEST NO. 2
Parameters
Chlorine Demand Free Water
Chlorine Dose (free) 18.20 ppm
pH=ll
Time24 hours
TemDerature=20°C
Pipe Material
Added
(gil)
Chlorine
Residual
PTHM
Free
(ppm)
Total
(ppm)
CHC1
(ppb
CHC1 9 Br
(ppb)
0.0
0.68
7.8
19
ND
0.0
0,60
8.6
17
ND
5.0
0.35
0.72
95
ND
5.0
1.05
1.38
109
ND
10.0
0.35
0.58
97
ND
10.0
0.08
0.35
83
ND
20.0
0.88
1.38
63
ND
20.0
0.05
1.08
62
ND
ND=Not
Detectable
73
-------
APPENDIX D
IN PIPE TEST
TABLE Dl. IN PIPE TEST OF APRIL 4, 1978
Time
(hours)
Pipe
Chlorine
Residual
Free
(ppm)
Cl 2
Total
(ppm)
Cl 2
CHC1.
(ppb’
CHC 1 2 Br
(ppb)
0
108
8
1.8
2.4
1
133
8
1.8
2.4
2
130
3
1.2
2.4
4
159
7
1.4
1.9
12
152
6
1.4
2.3
24
155
6
1.2
1.7
48
174
10
0.1
0.4
74
-------
TABLE 02. IN PIPE TEST OF APRIL 4. 1978
Time
(hours)
Baseline
Chlorine
Residual
CHC 1 3
(ppb)
CHC1 2 Br
(ppb)
Free Cl 2
(ppm)
Total Cl 2
(ppm)
0
108
2
1.8
2.4
1
138
7
-
-
2
137
7
-
-
4
145
10
-
-
12
155
7
-
-
24
160
8
-
-
48
196
14
1.1
1.5
72
196
6
1.3
1.5
96
-
-
-
-
120
199
8
0.8
1.0
144
203
7
0.8
1.0
75
-------
TABLE D3. IN PIPE TEST OF MAY 7, 1978
Time
(hours)
Pipe
Chlorine
Residual
CHC1 3 CHC1 2 Br
(ppb) (ppb)
Free Cl 2
(ppm)
Total Cl 2
(ppm)
0
198 42
1.2
1.5
12
194 32
0.6
1.0
24
188 50
0.4
0.8
48
219 50
0.0
0.5
TABLE D4. IN PIPE
TEST
OF
MAY
7,
1978
Time
(hours)
Baseline
Chlorine
Residual
Free Cl 2
(ppm)
Total Cl 2
(ppm)
cHc1 3 CHC1 2 Br
(ppb) (ppb)
0
161 11
1.2
1.5
12
183 29
-
-
24
197 49
-
-
48
180 25
-
-
96
226 30
-
-
144
248 41
-
-
192
236 41
-
-
240
266 48
0.60
0.95
76
-------
APPENDIX E
RAW WATER QUALITY DATA
TABLE El.
PHYSICAL WATER QUALITY
DATA FOR
THE RAW WATER
Date
Temp.
(°C)
pH
Specific
Conductance
(umhos/cm)
@ 25°C
Total
Residue
(ppm)
Chemical
Oxygen
Demand
(ppm)
Turbidity
(NTU)
7/ 7/77
-
8.0
940
675
66
28.0
7/ 8/77
-
8.4
940
675
56
22.0
7/13/77
-
8.5
1080
764
88
22.0
8/ 3/77
-
8.9
1053
805
190
30.0
8/ 5/77
—
8.9
1228
791
55
35.0
8/18/77
1131
770
22
31.0
9/21/77
-
8.3
1262
64
27.0
10/29/77
15.0
8.9
1366
457
34
11/15/77
6.0
8,8
1216
912
35
11/29/77
5.0
8.8
1315
38
6.0
1/ 4/78
4.0
8.5
1629
1130
23
6.0
1/18/78
3.0
9.1
1732
1260
15
5.0
1/30/78
3.0
7.8
2268
1691
54
4.0
2/13/78
4.0
7.8
2900
2209
54
2.0
2/27/78
4.0
7.2
2887
2520
60
12.0
3/10/78
3.0
7.7
1804
1257
8.0
3/13/78
3.0
7.7
1753
i158
26
7.0
3/24/78
3.0
7.6
464
339
44
18.0
4/ 4/78
7.0
7.5
4000
263
73
21.0
4/18/78
7.0
7.1
4600
312
36
31.1
5/ 2/78
13.5
8.8
496
329
24
7.4
5/10/78
10.0
8.6
590
405
29
6.7
77
-------
TABLE E2. PHYSICAL
WATER QUALITY
DATA FOR THE RAW WATER
Date
Suspended
Solids
(ppm)
Volatile
Suspended
(ppm)
NH 3 -N
(ppm)
PTHM
CHCl
(ppb7
CHC1 9 Br
(ppb7
7/ 7/77 127.0 42
7/ 8/77 59.0 29
7/13/77 34.0 20 0.06
8/ 3/77 84.0 56 0.13
8/ 5/77 47.0 12 0.10
8/18/77 42.0 14 0.03
9/21/77 52.2
10/29/77 29.0 17 0.04
11/15/77 14.0 1.03
11/29/77 10.0 5 0.13
1/ 4/78 12.0 7 0.16
1/18/78 7.7 1.1 371 45
1/30/78 15.0 7 0.81
2/13/78 5.0 1 0.05 -
2/27/78 10.0 7 0.41 408 56
3/10/78 9.0 7 0.27 340 58
3113/78 13.0 7 0.37 300 7
3/24/78 44.0 17 250 ND
4/ 4/78 59 6 530 7
4/18/78 46 8 - 603 5
5/ 2/78 15 5 0.01
5/10/78 31 3
78
-------
APPENDIX F
PTHM VS. CHLORINE DOSE
TABLE FL PTHM VS. CHLORINE DOSE SEPTEMBER 21, 1977
Parameters
Temperatu re 20°C
Time=24 hours
pH=8 .3
Raw Water Huron, South Dakota
Free
Chlorine
Dose
Chlorine
Residual
PTHM
Free
(ppm)
Total
(ppm)
CHC1
(ppb)
CHC1 Br
(pp )
(ppm)
5.2
0.27
0.82
22
ND
10.4
0.27
0.68
43
ND
20.8
0.48
1.57
93
26
41.6
28.12
35.62
164
22
79
-------
TABLE F2. PTHM VS. CHLORINE DOSE MARCH 24, 1978
Parameters
Temperature=20°C
Time=96 hours
pH l l
Raw Water From Huron. South Dakota
Free
Chlorine
Dose
(ppn)
Chlorine
Residual
PTHM
CHC1 3
(ppb)
CHC1 2 Br
(ppb)
Free
(ppm)
Total
(ppm)
9.9
0.75
0.88
51
27
19.8
0.05
0.15
131
6
29.7
0.05
0.30
523
39
39.6
0.09
0.55
586
45
Parameters
TABLE F3. PTHM VS. CHLORINE DOSE MAY 10, 1978
Temperature=20° C
Time 96 hours
pH=11
Raw Water From Huron, South Dakota
Free
Chlorine
Dose
(ppm)
Chlorine
Residual
PTHM
CHC1 3
b)
‘
CHC1 2 Br
‘ b)
‘
Free
(ppm)
Total
(ppm)
4.2
.
0.05
0.21
155
16
21.1
10.40
12.60
1959
112
31.60
22.00
23.00
1601
106
42.13
31.50
33.00
1882
111
80
-------
APPENDIX c;
CHLORINE DOSE AT THE TREATMENT PLANT
TABLE GI. PRECHLORINE PLUS POSTCHLORINE DOSE
Date Chlorine Dose
- (ppm)
1/18/78 10.21
1/30/78 12.93
2/13/78 13.34
2/27/78 13.97
3/13/78 19.17
3/24/78 20.87
4/ 4/78 11.49
4/18/78 9.2
5/ 2/78 6.18
5/10/78 6.59
81
-------
APPENDIX H
RIVER TRIP DATA
TABLE Hi. WATER QUALITY DATA, RIVER
TRIP JULY 13, 1977
River
Miles
pH
Specific
Conductance
(umhos/cm @ 25°C)
Chemical
Oxygen
Demand
(ppm)
Turbidity
NTU
0.00 8.5 862 46 55
1.62 8.9 900 73 125
3.62 8.6 1202 81 85
7.41 8.4 1497 80 50
9.94 8.5 1449 65 35
11.37 8.7 1351 49 45
12.35 8.7 1322 107 52
13.69 9.0 1250 131 150
14.66 9.2 1137 147 135
15.56 8.8 991 168 152
15.75 8.8 1035 141 150
17.22 9.6 944 137 130
18.10 9.3 943 129 155
18.90 9.6 975 102 124
19.63 9.1 1008 54 70
20.12 9.0 994 62
21.37 9.1 966 72 60
22.34 9.0 1031 60. 40
23.34 9.2 961 76 50
24.31 9.1 1005 68 55
25.18 9.2 1065 60 53
26.47 9.0 1050 127 52
27.63 8.9 929 108 35
28.62 8.7 111 58 37
82
-------
TABLE H2. WATER QUALITY DATA. RIVER TRIP JULY 13, 1977
River Miles Suspended
Solids
(ppm)
Volatile
Suspended
Solids
(ppm)
PTHM
CHC1
(ppb)
CHC1 2 Br
(ppb)
0.00
100
22
1300
244
1.62
182
47
2350
358
3.62
188
56
2130
516
7.41
163
47
1620
597
9.94
142
49
11950
224
11.37
155
68
1790
459
12.35
315
21
1950
193
13.69
320
39
‘
2500
429
14.66
251
48
3310
540
15.56
259
17
2230
105
15.75
222
117
2030
95
17.22
272
150
1400
.50
18.10
275
126
2150
95
18.90
202
121
2540
185
19.63
128
93
1820
130
20.12
109
52
1630
115
21.37
107
59
1120
90
22.34
67
45
1100
50
23.34
108
56
764
50
24.31
101
45
1080
65
25.18
77
42
1540
170
26.47
81
37
706
50
27.63
54
20
1480
140
28.62
‘52
22
987
140
83
-------
APPENDIX I
TOTAL ORGANIC CARBON DATA
TABLE II. TOTAL ORGANIC CARBON ANALYSES HURON, SOUTH DAKOTA
Date
Station
Total Organic Carbon
(ppm)
10/14/77
Raw Water
16.00
2/13/78
Raw Water
20.95
2/14/78
Raw Water
21.81
2/14/78
Clear Well
1.58
2/14/78
Airport
1.81
3/29/78
Raw Water
12.76
3/29/78
Primary Sedimentation
9.06
3/29/78
Upflow Basin
8.97
3/29/78
Above Filters
1.35
3/29/78
Below Filters
0.92
3/29/78
Clear Well
0.92
84
-------
APPENDIX J
TOTAL COLIFORM DATA
TABLE Ji. TOTAL COLIFORM COUNTS OVER A ONE AND A HALF
HOUR PERIOD AT STATION 1 AND 5
Station 7/13/77 Total Coliforms
Time 100 ml
1 2:15 pm 5,800;l0,500*
5 2:15 pm 1O;27
1 2:45 pm 17,800;9,200
5 2:45 pm 25;27
1 3:15 pm 15,300;ll,800
5 3:15 pm 65;55
1 3:45 pm 12,800;17,800
5 3:45 pm 15;50
*Duplicate Determinations
85
-------
TABLE J2. TOTAL COLIFROM SAMPLES FROM STATION 2 AND THE
EFFECT OF DH ON BACTERIAL SURVIVAL, JULY 20, 1977
Total _ COl iforms/100 ml
p1 pH 10
Time (mm.) pH 8
pH 11
0 13,500;11,900*
15 12,400; 9,000 12,400;1O,100 7,600; 7 OO
2,600;2,000
30 12,800;10,900 6,200; 6,100 7,000; 6,600
2,200;1,400
60 18,200;12,900 9,800; 7,300 10,200:11,300
600; 680
120 31,600;19,500 16,400;13,800 3,400: 3,760
500; 600
140 17,400,12,500 22,800,19,400 13,300.12,120
0, 0
Note: Initial pH = 8.04, Temperature = 21°C
TABLE J3. TOTAL COLIFORM SURVIVAL AT STATION 2 USING
MONOCHLORAMINE, JANUARY 25, 1978
Total ColiR rmS/l00 ml
NH 2 C1C1 2 Th tention Time (hrs.)
Dose (ppm) 0.75
2.0
0 200;300
2.5 O;O
O;O
5 O;0
0;0
10 O;O
O;0
15 0;O
O;0
*Dupl icate Determinations
Note: pH = 7.8, Temperature = 4°C
4:1 C1 2 :NH 3 -N (by weight)
86
-------
TABLE J4. TOTAL COLIFORM SURVIVAL AT STATION 2 USING
MONOCHLORAMINE AND oH. FEBRUARY 2, 1978
Total Coliforms/lOO ml
NH 2 C1 -Cl 2
Detention Time (hrs.)
Dose (ppm) 0.5 1.75
3
0 l,250;972*
2.5 O;O O;O
0;O
5 O;O O;O
O;O
10 O;O O;O
O;O
*Dupl icate Determinations
Note: pH = 10.5, Temperature = 3°C
4:1 2 C1 3 NH -N (by weight)
TABLE J5. TOTAL COLIFORM SURVIVAL AT STATION 2 USING
MONOCHLOR.AMINE, FEBRUARY 17, 1978
Total Coliforms/100 ml
NH Cl-Cl Detention Time (hrs.)
Do e (pp ) 0.5
2.0
0 15,000
2.5 28
0
5 0
0
10 0
0
Note: pH = 7.8, 4:1 C1 2 NH 3 -N (by weight)
87
-------
APPENDIX K
ARTIFICIAL SPIKING DATA
THM AND OTHER DATA IN DECHLORINATED
ARTIFICIAL SPIKING EXPERIMENT
Tot. Coliform
100 ml
TABLE Ki.
Date pH
SAMPLES DURING
CHC1 3
- (ppb)
CHC 1 2 Br
(ppb)
3/3/78
9.5
0
4
3
3/10/78
0
4
2
3/15/78
9.6
0
5
3
3/17/78
0
5
3
3/25/78
8.8
0
8
7
3/28/78
9.1
0
8
10
4/ 4/78*
9.2
0
11
4
4/10/78*
9.6
0
10
4
4/18/78*
8.5
0
34
4
4/24/78*
10.5
0
40
4
*pre_Chlorjnated at high pH.
88
-------
Date
H
Chlorine
dose (ppm)
Chlorine
Residual (ppm)
CHC1 3
(ppb)
CHC1 2 Br
(ppb)
Free
Total
3/ 3/78
9.5
9
0.1
1 .6
47
21
3/10/78
9
0.1
2.6
38
14
3/15/78
9.6
9
0.1
1.71
42
14
3/17/78
15
0.0
0.2
40
18
3/25/78
8.8
20
0.9
1.65
79
27
3/28/78
9.1
20
9.4
10.4
36
22
4/ 4/78* 9.2
15
7.0
12.8
184
15
4/10/78* 9.6
15
6.7
7.1
149
12
4/18/78* 8.5
15
10.5
12
91
11
4/24/78* 10.5
15
10.4
11
101
9
TABLE K2.
THM AND OTHER DATA IN CHLORINATED SAMPLES DURING
ARTIFICIAL SPIKING EXPERIMENT
*pre_chlorjnated at high pH.
89
-------
0
TABLE K3. THM AND OTHER DATA IN AMMONIATED SAMPLES DURING
ARTIFICIAL
SPILUNG
EXPERIMENT
Date
pH
Tot. Coliform
Chlorine
Residual
(ppm)
C 1 2 :NH 3 -N
Ratio
CHC 1 3
(ppb)
CHCl
(ppb)
100 ml
Free
Total
3/ 3/78
0
0.3
4.6
3:1
15
7
3/10/78
0
0.3
4.1
3:1
9
6
3/15/78
9.6
0
0.35
3.8
4:1
17
8
3/17/78
0
0.0
0.4
4:1
22
9
3/25/78
8.8
0
0.3
1.7
4:1
18
12
3/28/78
9.1
0
0.2
19.8
4:1
15
13
4/ 4/78*
9.2
0
0.15
12
4:1
117
6
4/10/78
9.6
0
0.2
13.4
4:1
64
6
4/18/78*
8.5
0
0.4
13.6
4:1
50
5
4/24/78*
10.5
0
0.4
3.1
2:1
45
5
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO. [ 2.
EPA -600/2-80-091 I
3. RECIPIENT’S ACCESSION NO.
4. TITLE ANO SUBTITLE
PREVENTING HALOFORM FORMATION IN DRINKING WATER
5. REPORT DATE
August 1980 (Issuing Date)
6.PERFORM ING ORGANIZATION CODE
7. AUTHOR(S)
Leland L. Harms and Robert W. Looyenga
8. PERFORMING ORGANIZATION REPORT NO.
I. PERFORMING ORGANIZATION NAME AND ADDRESS
South Dakota School of Mines and Technology
Rapid City, South Dakota 57701
10. PROGRAM ELEMENT NO.
11 J . I CT/GRANTNO
R8051 49-01-0
12. SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Final 5/77 - 2/79
14.SPONSORINGAGENCYCODE
EPA/600/14
15. SUPPLEMENTARY NOTES
Project Officer: 0. Thomas Love, Jr. (513) 684-7281
16. MQ I r MCT
The Huron, South Dakota, water distribution system was monitored for trihalo-
methanes at several locations. Deposits from within the distribution system were
evaluated as potential precursor material and were found to be precursors for
the haloform reaction. Field tests designed to determine the extent of trihalo-
methane formation that occurs as a result of the pipe deposits were inconclusive.
The deposits appear to be a precursor source, but they do not substantially alter
the terminal trihalomethane concentration.
Ammonium sulfate was used to convert to a combined chlorine residual in the
distribution system. A significant drop in trihalomethane concentrations was
obtained along with maintenance of adeQuate disinfection. Primary disinfection was
obtained by lime softening followed by a free chlorine residual.
Land used upstream from the raw water intake was evaluated for potential
chloroform formation. Peak concentrations occurred near marshes, where cattle watered,
and where the river was stagnant.
Nine raw water quality parameters were monitored and correlated with THM formation.
The best correlations were obtained with specific conductance and turbidity.
17. KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDEN.TIFIERS/OPEN ENDED TERMS
C. COSATI Fie (d/Group
Chlorine-containing compounds
Chlorination
Disinfection, disinfectants
Chloroform
Water treatment
Potable water
Agricultural wastes
13B
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (This Report)
UNCLASSIFIED
21. NO. OF PAGES
101
20. SECURITY CLASS (This page)
UNCLASSIFIED
22. PRICE
EPA Fo,,n 2220—1 (R.v. 4—77)
91
* U.S. GOVERNMENT PRINTING OFFICE 98O--657-I65/OlO 2
------- |