EPA-600/4-78-010
January 1978
Environmental Monitoring Series
AN AUTOMATIC CHLORINATION SYSTEM FOR
ELIMINATING BIOLOGICAL GROWTH IN PUMPING
SYSTEMS FOR AUTOMATIC INSTRUMENTATION
Environmental Monitoring and Support Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL MONITORING series.
This series describes research conducted to develop new or improved methods
and instrumentation for the identification and quantification of environmental
pollutants at the lowest conceivably significant concentrations. It also includes
studies to determine the ambient concentrations of pollutants in the environment
and/or the variance of pollutants as a function of time or meteorological factors.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/4-78-010
January 1978
AN AUTOMATIC CHLORINATION SYSTEM FOR
ELIMINATING BIOLOGICAL GROWTH IN
PUMPING SYSTEMS FOR AUTOMATIC INSTRUMENTATION
by
Richard P. Lauch
Instrumentation Development Branch
Environmental Monitoring and Support Laboratory
Cincinnati, Ohio,45268
ENVIRONMENTAL MONITORING AND SUPPORT 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 Environmental Monitoring and
Support Laboratory - Cincinnati, U.S. Environmental Protection Agency,
and approved for publication. Mention of trade names or commercial
products does not constitute endorsement or recommendation for use.
ii
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FOREWORD
Environmental measurements are required to determine the quality of
ambient waters and the character of waste effluents. The Environmental
Monitoring and Support Laboratory - Cincinnati conducts research to:
Develop and evaluate techniques to measure the presence
and concentration of physical, chemical, and radiological
pollutants in water, wastewater, bottom sediments, and
solid waste.
Investigate methods for the concentration, recovery, and
identification of viruses, bacteria and other microbio-
logical organisms in water. Conducts studies to determine
the responses of aquatic organisms to water quality.
Conduct an Agency-wide quality assurance program to assure
standardization and quality control of systems for moni-
toring water and wastewater-.
The Instrumentation Development Branch, EMSL, investigates the per-
formance of instrumentation and the requirements for the collection and
storage of representative waste samples. In this study, an automatic
chlorination system for the elimination of biological growths in a sam-
pling system has been evaluated.
Dwight G. Ballinger
Director
Environmental Monitoring and Support Laboratory
Cincinnati
111
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ABSTRACT
Automatic chlorination was determined to be satisfactory for
elimination of microbial growth (slime) in monitor pumping systems.
With chlorination, changes in dissolved oxygen levels through the
sampling system were minimized. Optimum chlorine concentration and
frequency of chlorine addition to the system were determined during
the period of maximum biological activity.
IV
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CONTENTS
Foreword iii
Abstract iv
Figures vi
Tables vi
1. Conclusions and Recommendations 1
2. Introduction 3
3. Description of System 4
4. Computation of Chlorine Concentration and Methods of
Sample Analysis 8
5. Results . . • 10
Cold Weather Tests 10
Warm Weather Tests 10
6. Problems Encountered, Solutions 16
References 17
Appendices
A. Tables 4 through 12, Chlorination System Tests 18
B. Figure 6 - Air Separator Assembly 23
C. Parts List. . . t 24
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FIGURES
No.
1
2
3
4
5
6
Flow Diagram ,
Timing Circuit .
Chlorine Shelter .....
DO-Change Immediately After the Chlorination at the
Feed Rate Shown,
DO-Change 23 Hours After Chlorination at the Feed
Rate Shown
Air Separator Assembly . . . ,
5
6
7
14
14
23
Tables
No.
1
2
3
4
5
6
7
8
9
10
11
12
Cold Weather Data
Background Data Before Chlorination.
Final Days Testing After Chlorination
Chlorination System Tests, 7/12/72
Chlorination System Tests
Chlorination System Tests
Chlorination System Tssts
Chlorination System Tests
Chlorination System Tests
Chlorination System Tests
Chlorination System Tests,
7/13/72 . . .
7/14-15-16/72
7/17/72 . . .
7/18/72 . . .
7/19-20/72. .
8/8/72. . . .
8/9/72. . . .
Chlorination System Tests, 8/10/72
Page
11
12
13
18
18
19
19
20
20
21
21
22
VI
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SECTION 1
CONCLUSIONS AND RECOMMENDATIONS
o This investigation has shown that automatic chlorination is an effective
method for eliminating microbial growth (slime) from the inner pipeline
surfaces of pumping systems for automatic instrumentation.
o A gaseous chlorine feed rate of at least 2 to 2-1/2 pounds per day, added
to the system once a day for 10 minutes was the minimum quantity of
chlorine required to keep the dissolved oxygen (DO)-change caused by
microbial metabolism, minimal. Total flow rate through this system was
18 gpm and during chlorination one-half of this was diverted through the
chlorinator and then recirculated. A chlorine feed rate of 2 pounds per
day gives a peak calculated concentration of 18.51 mg/1. Sample analysis
revealed that there was 9.6 and 10.4 mg/1 of free and total residual
chlorine respectively within the system when it was approximately one-
half charged. DO samples that were collected, across the pumping system,
23 hours after this chlorination cycle gave an average DO-change of zero.
This average was made up of 5 DO-change readings that ranged from -0.05
to +0.05 mg/1. These tests were made during the warm weather periods of
July and August when microbial growth was at a maximum.
o The average, of 10 DO-change readings across the system before any appli-
cation of chlorine, was 0.28 mg/1 with a range of 0 to 0.5 mg/1.
o Settled sludge within the inlet strainer will cause high and erratic DO-
change readings.
o This system had a flow rate of 18 gpm and incorporated 200 feet of 1-1/4
inch ID and 300 feet of 1-1/2 inch ID line. Therefore sample velocities
were 4.71 and 3.26 feet per second respectively.
o It is recommended first, that pumping systems be designed with a high
velocity of flow (greater than 4.7 ft/sec) for minimal sample degrada-
tion. They should be straight-through systems with no enlarged sections
where sludge can settle. Pipelines should be made of high density
material that minimize the small cavities where microbial growth can
get started and pipeline length should be kept as short as possible.
Inlet strainers should be easily accessible so that they can be cleaned
frequently, thus eliminating sludge build-up.
o Need for automatic chlorination can be determined by testing for DO loss
across the system during the warm months.
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o In my opinion, automatic chlorination is probably not required for
properly designed systems during cold weather when biological metabolism
is slow. Chlorination may not be required during warm weather for prop-
erly designed systems on streams where pollution is light. It may be
that there is a sample velocity, within a properly designed system, above
which sample degradation would be insignificant. If there is such a
velocity, then the system should be designed for same, hence eliminating
the need for automatic chlorination. More research is needed in this
area to determine this velocity for specific line lengths and degrees of
sample pollution.
o If it is determined that automatic chlorination is required, after proper
system design, then this study has shown that chlorination at low concen-
tration is a satisfactory method for minimizing sample change that results
from microbial growth within the pumping system.
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SECTION 2
INTRODUCTION
A pumping system that delivers raw water sample flow to automatic
instrumentation should be designed for minimum sample change. Stierli (1)
discussed the importance of high sample velocity for minimal DO change.
Lauch (2) explains that sample change does occur in a system that allows
low velocity of flow and settling. Lauch (3) discusses intake system
design for minimal sample change.
In a properly designed system, slime bacteria may still.grow on the
inner pipe surfaces and cause sample change when polluted water is pumped
through long lines during warm weather periods. The severity of this
change may or may not be significant enough to warrant automatic cleaning.
This report describes the design and evaluation of an automatic system
that periodically chlorinates the lines to remove slime microbes. The sys-
tem was evaluated during cold and warm weather to determine the optimum
quantity and frequency of chlorination. This evaluation was performed at
a field test station on the Little Miami River at Cincinnati, Ohio.
DO was the parameter used to determine sample change within the pump-
ing system. DO is an obvious parameter to use because it is easily and
accurately measured; however, since a decrease in DO results from microbial
metabolism, it must be noted that other less conspicuous parameters may be
changing as well.
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SECTION 3
DESCRIPTION OF SYSTEM
A complete parts list for this chlorination system is given in the
Appendix. Figure 1 depicts a flow diagram of the system with inset illus-
trating a typical valve cycle. The total flow through the chlorination
system was 18 gpm. The manifold shown within the dotted lines is located
inside the instrumentation shelter, V]_, V^, and ¥3 are automatic valves.
Flow control valves (FCV) were used to balance the system. The first stage
pump was submerged in the river, and the second stage pump was located
between the river and shelter. The total length of sample line between the
river and shelter was approximately 500 feet (91.44 m)• Refer to Figure 1
for an explanation of a typical valve cycle:
Normally Vj is closed and sample flow is from the river to
the monitor. When chlorination is required, Vj opens and
1 minute later ¥2 closes; the lag eliminates the possibi-
lity of restricting positive-displacement pumps. With ¥2
closed, half of the flow'is to the monitor and the other
half (9 gpm) goes through Vj. After Vj the flow divides
with 4 gpm going through the ejector to develop a negative
pressure at ¥? and 5 gpm mixing with the ejector effluent
for greater dilution of C^. When the return side of the
system is stabilized (air eliminated), V, opens and chlorine
gas is drawn into the system. The resulting chlorinated
water flows to the inlet of the first stage pump, and after
10 minutes of chlorination ¥3 closes. The system flushes
with non-chlorinated water for 18.6 minutes, ¥2 opens, and
1 minute later Vj closes; the cycle is completed.
The valve cycle was controlled by the timing circuit shown in Figure
2 and the following is a sequential explanation of events that were con-
trolled by this circuit:
1. 85 closes according to the setting of the 24-hour timer. 85
(power relay) closes and valve Vj opens. The magnet (MAG) is
energized through the delay; Sy closes and powers the motor (M)
of the cam timer. The delay coil de-energizes and magnet power
is off.
2. S7 closes and powers \2> nence V2 closes.
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2nd. STAGE
PUMP
ancLi CK —\.
TYPICAL VALVE CYCLE
1st. STAGE
PUMP
10 20 30
TIME (MINUTES)
40
•AIR SEPARATOR
Figure 1. Flow diagram
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3. $3 closes, the interval timer starts and solenoid valve V3 opens
for a precise period of time.
4. The interval timer closes
5.
6.
7.
8.
84 changes position and V^ opens.
S^ changes position and Vj_ closes.
S,. opens, hence S^ opens.
Sy opens after 1 hour has elapsed.
This completes the valve cycle.
Note that the cam timer was set up to eliminate all backlash. The
interval timer is a precision device and therefore it was used to control
¥3 and allow Cl2 to enter the system for an exact period of time. Since
one of the purposes of these tests was to determine the quantity and fre-
quency of chlorination, an accurate and precise control function was
required. For routine intake cleaning a combination of the 24-hour timer
and the cam timer would suffice (eliminating the interval timer). It may
also be possible to use a signal from the instrumentation to start a cam
timer and this would eliminate the 24-hour timer.
120 VAC
POWER^ 24
RELAY
TIMER
Figure 2. Timing circuit.
6
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The cylinder of chlorine gas was located in a small shelter that was
separated from the main instrumentation shelter (Figure 3). The chlori-
nator was attached directly to the top of this cylinder and included a
flowmeter with needle valve for setting chlorine flow rate. This type of
chlorinator supplies chlorine gas to the system only when a negative pres-
sure is developed by pressurized water flowing through the ejector. If
water flow stops because of pump failure, chlorine flow will also stop.
This is an excellent safety precaution. Chlorinator ejector combinations
of this type are commercially available from a number of manufacturers.
One objective of these tests was to show that a very small quantity of
chlorine is sufficient to eliminate slime growth in the lines. For
example, if a chlorine feed rate of 2 pounds per day added to the system
for 10 minutes, once a day during the 6-warm weather months is sufficient
to eliminate slime bacteria, then a small 15-pound cylinder of chlorine
would last longer than 5 years.
Figure 3. Chlorine shelter.
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SECTION 4
COMPUTATION OF CHLORINE CONCENTRATION
AND METHODS OF SAMPLE ANALYSIS
During chlorination half of the flow goes through Vj, is chlorinated
at the ejector, and then returns to the pump inlet (Figure 1). The other
half flows into the monitor and then to waste. Half of the flow entering
the pump inlet is chlorinated and the other half is new river water.
Assume that the initial chlorine concentration in the return line immediate-
ly after the ejector is C. When this concentration enters the first stage
pump inlet, the new concentration in the monitor line is approximately C/2.
When C/2 reaches the ejector, the new concentration in the return line is
approximately C + C/2. The concentration of C + C/2 again enters the pump
inlet, is diluted in half and becomes (C + C/2)/2. The following equations
give the chlorine concentration below and above the ejector.
n n.
Below ejector, concentration = C ^> 1 + (1/2) X£» 2C (1)
nT = 1
n n.
Above ejector, concentration = C ^> (1/2) ^ C (2)
nT = 1
where C = the initial concentration just after
ejector
n = number of complete cycles
elapsed time
residence time of system
Also: n is an integer so that only completed cycles are employed
residence time of return line = approximately 2.6 minutes
residence time of monitor line = approximately 2.1 minutes
residence time of system = approximately 4.7 minutes.
Note that the concentration within the return line approaches 2C, and
the concentration in the monitor line approaches C. After three cycles
(approximately 14.1 minutes), the concentration in the monitor line at V^
is 0.875C (equation 2). Therefore, it takes a few cycles for the monitor
line to build up to maximum concentration; it is also necessary to leave
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the return line flush for a period of time with ¥3 closed to remove all
chlorine from the system.
METHOD OF SAMPLE ANALYSIS:
DO - Azide Modification of the Winkler Method (4)
Chlorine - DPD Ferrous Titrimetric Method (4)
Temperature - Matheson Thermometer, Catalog No. 62109-10
1 to 51C. Division I/IOC.
pH - Instrumentation Laboratory, Inc. pH/mV Electrometer Model 245.
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SECTION 5
RESULTS
After initial installation, the system was checked during cold weather
and baseline information was obtained. The system was then tested during
warm weather to determine minimum concentration and frequency of chlorina-
tion during the period of maximum biological activity.
COLD WEATHER TESTS
These tests were run at chlorine feed rates of 1 pound per day and 1/2
pound per day. Samples were taken from the monitor line inside the shelter
(Figure 1). Table 1 shows that after 8.6 minutes of chlorination, the
median total chlorine residuals were 4.1 mg/1 and 2.3 mg/1 at feed rates of
1 pound per day and 1/2 pound per day respectively. This compares to
values, that were calculated and applied to equation 2, of 4.6 and 2.3 mg/1
and shows that substantially all of the chlorine added was recirculating.
Table 1 illustrates that free chlorine residual was a substantial part of
the total chlorine residual and that addition of chlorine lowered the pH of
the water slightly. Lowered pH is desirable because the hypochlorous acid
(HOC1) component of the free residual is the chlorine species that is most
effective for killing microbes and this species becomes more predominent as
pH decreases (5).
WARM WEATHER TESTS
Warm weather tests were performed from July 11 through August 11, 1972,
to determine the optimum quantity of chlorine and frequency of chlorine
addition for this system during the period of maximum biological activity.
Results are as follows:
7/11/72
The system had been running continuously for 2 weeks prior to this
date without chlorination. Tests were performed this day to obtain
background information without the addition of chlorine. A sample
for DO was taken at the river inlet and inside the shelter, from the
monitor manifold, approximately every 1/2 hour throughout the day.
The shelter sample was taken approximately 3 minutes after the river
sample to allow for residence time. Differences in DO between the
river and the shelter are given in Table 2.. Average DO-change across
the system this day was 0.28 mg/1. Two erratic DO readings after a
heavy rain shower were not included in this average because these
10
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Table 1. COLD WEATHER DATA*
12/1/71
Chlorine Feed Rate
= 1 Ib./day
Time
10:20f
10:32
10:50
11:00
ll^O1"
11:32
11:50
12:00
l:00f
1:12
1:30
1:40
Measured chlorine
concentration (mg/lj
free total
residual residual
3.0
0.0
0.0
3.1
0.0
0.0
3.1
0.0
0.0
4.0
0.7'
0.0
4.2
0.5
0.0
4.1
0.7
0.0
pH
shelter
7.6
8.0
8.0
7.4
7.8
7.9
7.4
7.8
7.9
Temp.
C°
7.0
7.0
5.3
6.8
6.2
5.6
6.7
6.5
5.8
DO (mg/1)
river shelter
Chlorine Feed Rate
= 0.5 Ib./day
2:10
2:22
2:40
2:50
3:05
3:20f
3:32
3:50
4:00
4:15
4:20f
4:32
4:50
5:00
1.7
0.0
0.0
1.2
0.0
0.0
1.0
0.0
0.0
2.8
0.2
0.0
2.3
0.2
0.0
2.2
0.5
0.0
7.5
7.8
7.9
7.4
7.9
8.0
7.5
7.8
8.0
6.5
6.7
5.4
6.1
6.1
5.3
6.3
5.9
5.0
12.7 12.90
12.7 12.75
*Cl2 valve ¥3 opens 3.4 minutes after cycle starts
Cl2 added for 10 minutes
Total length of cycle = 33 minutes.
^Start of chlorination cycle.
11
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readings probably resulted from an abnormal stirring up of a sludge
deposit inside of the inlet strainer. It is also possible that the
increased DO-change was caused by the pipeline slime microbes metabo-
lizing a higher substrate concentration that was washed into the
stream during the shower.
Table 2. BACKGROUND DATA BEFORE CHLORINATION
7/11/72
Time
9:45a.m.
10:30
11:00
11:30
12:OON
12:30p.m.
1:00
2:30
3:00
3:30
4:00
5:05
DO
river
8.95
9.10
9.20
9.05
9.20
9.35
9.30
10.20
10.60
9.90
9.80
7.80
DO
(mg/1) change
shelter (mg/1)
8.70
8.70
8.70
8.80
8.95
9.05
,9.10
10.00
10.60
7.45
8.65
7.40
Average
-0.25
-0.40
• -0.50
-0.25
-0.25
-0.30
-0.20
-0.20
0.00
-
-0.40
DO = -0.28
Temperature °C
river shelter Remarks
23.1
23.1
23.6
23.4
23.5
23.4
23.2
23.6
24.1
24.2
24.4
24.6
23.0
23.0
23.1
23.1
23.2
23.2
23.2
23.8
24.0
23.8 Heavy shower
24.1
24.6
8/11/72
The data for this final day of testing are shown in Table 3. Prior
to and during these tests, chlorine was being added to the system at
a rate of 3 pounds per day for 10 minutes three times a day. The
inlet strainer was cleaned three times between 7/11 and 8/11/72.
The average DO change on 8/11/72 was 0 mg/1 before chlorination and
0.005 mg/1 after chlorination, which when compared with the average
DO change on 7/11/72 shows that automatic chlorination along with
inlet strainer cleaning is an effective method for decreasing sample
change across the system.
7/12 through 8/11/72
The purpose of these tests was to determine the minimum quantity and
frequency of chlorine required for effective cleaning of this specific
system during the period of maximum biological activity. Data for
these tests are included in Table 3 and Tables 4 through 12 of the
Appendix. During these tests the number of chlorine cycles per day
were increased as follows:
12
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Table 3. FINAL DAYS TESTING AFTER CHLORINATION
8/11/72
Time
9
9
9
9
10
10
10
10
10
10
10
10
11
11
11
11
12
12
2
2
3
3
4
: 00a.m.
-.15
:30
:45
:00
:06
:11
:16
:21
:26
:33
:43
:00
:15
:30
:45
: 25p.m.
-.40
:00
:30
:00
:30
:00
DO
river
9
9
9
9
.25
.40
.70
.95
Start
10
11
11
11
12
12
14
14
15
16
16
.80
.00
.20
.50
.15
.70
.40
.60
.20
.00
.50
(mg/1)
shelter
9
9
9
10
.30
.35
.55
.10
Cl2 cycle, rate
10
11
11
11
12
12
14
14
IS
15
16
.85
.05
.10
.40
.15
.80
.55
.70
.35
.95
.10
Average =
DO
change
(mg/1)
0.05
-0.05
-0.15
0.15
= 3#day,
0.05
0.05
-0.10
-0.10
0.00
0.10
0.15
0.10
0.15
-0.05
-0.40
-0.005
Temperature °C pH
river shelter shelter
20.9 21
20.7 21
20.7 21
21.0 21
cycles/day = 3
22
22
23
23
24
24
24
24
24
.2
.3
.4
.6
7.16
7.18
6.70
6.95
6.98
7.24
7.51
.4
.5
.2
.4
.2
.4
.5
.7
.7
Chlorine
free
residual
0.0
10.0
17.6
8.8
2.9
0.9
0.0
(mg/1)
total
residual
0
11
21
8
3
1
0
.0
.2
.2
.8
.4
.3
.0
Once a day at 10:00 a.m.
Twice a day at 10:00 a.m. and 10:00 p.m.
Three times a day, 10:00 a.m., 6:00 p.m., and 2:00 a.m.
Five DO samples were taken across the system approximately 15 minutes
apart, before and after the 10:00 a.m. chlorination cycle. During a
chlorination cycle, readings for free and total chlorine residuals
along with pH were taken initially, approximately at peak concentra-
tion, at the end of the cycle, and 10 minutes after the end of the
cycle.
The DO-change data from Tables 4 through 9 (Appendix) are summarized
in Figures 4 and 5. Figure 4 shows data just after the chlorination
cycle ends and Figure 5 displays data 23 hours after a chlorine cycle
ended. The objective was to determine the chlorine concentration, in
Figure 4, that gave minimum DO change (for chlorination once a day)
and then start increasing the frequency of chlorination each day until
the DO change just before the 10:00 a.m. cycle equaled zero. Figure 5
shows that an average DO change of zero was obtained when chlorine was
added once a day at a feed rate of 2 pounds per day. The next day
(after a feed rate of 2.5 pounds per day) the average DO change was
0.09 mg/1. The pumping system went off, for some unknown reason, the
evening before these data were taken and this probably caused the
slight increase in DO-change. Figure 4 shows that the average DO-
change, immediately after chlorination, at chlorine feed rates of 2.5
13
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O)
E
CO
>•
to
to
CO
o
Oi
u
o
z
6
o
0.4
0.3
0.2
-0.1
T
T
T
T
T
CURVE IS 2ND. ORDER POLYNOMIAL REGRESSION
GOODNESS OF FIT R2 = 0.71
PTS. AT X= 1.5 WERE DELETED
CLEANED INTAKE STRAINER BETWEEN X=1.5 AND 2.0
CHLORINE FEED RATE (Ib/day)
0.5 1.0 1.5 2.0 2.5 3.0
Figure 4. DO-Change immediately after chlorination at the feed rate shown
0.3
0.2
CURVE IS 2ND. ORDER POLYNOMIAL REGRESSION
GOODNESS OF FIT R2 = 0.85
PTS. AT X = 2.5 WERE DELETED
PUMP PROBLEMS OCCURRED BETWEEN X =2.0 AND 2.5
0:5 1.0 1.5 2.0 2.5 3.0
Figure 5. DO-Change 23 hrs. after chlorination at the feed rate shown
14
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and 3 pounds per day were 0.01 and -0.01 mg/1 respectively
(essentially zero). Therefore, these tests show that chlorine feed
rates of at least 2 to 2.5 pounds per day, added to the system once
per day was sufficient to keep biological growth and therefore DO-
change minimal.
Testing was continued (Tables 3 and 10, 11, 12, Appendix) at chlorine
feed rates of 2.5 and 3 pounds per day and 2 to 3 chlorination cycles
per day with no additional significant reduction in DO-change. It was
therefore concluded that a minimum chlorine feed rate of 2 to 2.5
pounds per day, added to the system once a day for 10 minutes was
sufficient to keep this system free of biological growth, hence mini-
mal DO-change. A chlorine feed rate of 2 pounds per day gives a peak
calculated total residual concentration of 18.51 mg/1.
Figure 4 shows a step change in data points between feed rates of
1.5 and 2 pounds per day. The strainer was cleaned of sludge between
these two settings and this is probably the reason for the step change
The second order polynomial regression curves (Figures 4 and 5) were
calculated on a Tektronix 4051 using their Mathematics Plot 50 Tape,
Volume 2. These calculated points are depicted by the triangles in
the figures.
15
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SECTION 6
PROBLEMS ENCOUNTERED, SOLUTIONS
Along with normal debugging, one significant problem was that of
eliminating air from the return line at the start of a chlorination cycle.
At this specific location there is about 40 feet of elevation between the
river and the shelter. With Vj closed (Figure 1) a considerable negative
pressure developed in the return line, and both gauges 64 and 65 read lower
than atmospheric. With V]_ open during a chlorination cycle, 65 was still
reading negative. At negative pressures dissolved gases will come out of
solution, and also air can be sucked into the system. Initially, there was
very little clearance between the exit from the return line and the inlet
to the first stage pump. The air could not escape from the system and it
kept recirculating and caused severe fluctuation in water flow.
Two modifications were made to eliminate the problem:
1. A 9-gpm flow control valve (FVC) was installed in the return line
near the first stage pump to keep positive pressure in the return line
during a chlorination cycle.
2. An air separator (Figure 6, Appendix) was installed at the exit of
the return line just before the inlet to the first stage pump. The
horizontally installed separator reduced the velocity of the return
flow and allowed clearance before the pump inlet for air to escape.
This separator was an in-house design that performed satisfactorily
during these tests. Commercial air separators are also available.
16
-------
REFERENCES
1. Stierli, H., and J, D. Buck. An Experiment to Determine the Relation
Between Dissolved Oxygen Change in Pipeline Flow and Reynolds Number.
Basic Data Branch, U.S. Public Health Service, Cincinnati, Ohio,
December 1963.
2. Lauch, R. P. An Evaluation of a Well Type Pumping System for Automatic
Water Quality Monitors. Analytical Quality Control Laboratory, U.S.
Environmental Protection Agency, Cincinnati, Ohio, December 1970.
3. Lauch, R. P. Recommended Design of Sample Intake Systems for Automatic
Instrumentation. EPA-600/4-75-012, U.S. Environmental Protection
Agency, Cincinnati, Ohio, November 1975.
4. American Public Health Association. Standard Methods for the Examina-
tion of Water and Wastewater. 13th Edition. Washington, D.C., 1971.
5. Fair, G. M., J. .C. Geyer, and D. A. Okun. Water and Wastewater
Engineering. Volume 2. John Wiley and Sons, New York, N.Y., 1968.
17
-------
APPENDIX A
Table 4. CHLORINATION SYSTEM TESTS
7/12/72
Time
8:30a.m.
8:45
9:00
9:15
9:30
10:00
10:06
10:16
10:33
10:43
11:45
12:OON
12:15p.m.
12:30
12:45
DO (mg/1)
river shelter
7.35
7.15
7.15
7.20
7.10
Start
8.40
8.65
8.60
9.00
9.20
6.95
7.00
6.95
7.00
6.90
Average
Cl2 cycle
8.20
8.30
8.65
8.70
9.00
Average
DO
change
(mg/1)
-0.40
-0.15
-0.20
-0.20
-0.20
DO = 0.23
, rate = slightly
-0.20
-0.35
0.05
-0.30
-0.20
DO = 0.20
Temperature °C pH
river shelter shelter
22.8
22.7
22.9
22.9
23.0
> 0.5#/day
23.9
23.9
24.2
24.2
24.4
22.9
22.9
23.0
23.1
23.1
, cycles/day = 1
7.9
7.6
7.9
8.1
23.8
23.8
24.0
24.1
24.3
Chlorine (mg/1)
free total
residual residual
0.4 1.3
4.1 5.5
O.S 0.8
0.2 0.2
Table 5. CHLORINATION SYSTEM TESTS
7/13/72
Time
8: 30a.m.
8:45
9:00
9:15
9:30
10:00
10:06
10:16
10:33
10:40
11:00
11:15
11:30
11:45
12:OON
DO
DO (mg/1) change
river shelter (mg/1)
7.50
7.50
7.35
7.55
7.60
Start
8.20
8.40
8.50
8.75
9.00
7.35
7.45
7.25
7.40
7.40
Average
Cl2 cycle
8.20
8.20
8.45
8.60
8.80
-0.15
-O.OS
-0.10
-0.15
-0.20
DO = 0.13
, rate = l#/day
0.00
-0.20
-0.05
-0.15
-0.20
Temperature °C
river shelter
23.5
23.7
23.7
23.9
24.0
24.8
24.8
24.9
25.1
25.2
23.8
23.8
23.9
24.0
24.0
24.7
24.7
24.9
25.0
25.1
Chlorine (mg/1)
pH free total
shelter residual residual
7.95 0.0 0.3
7.53 7.2 8.1
7.83 0.4 1.0
7.92 0.0 0.0
18
-------
Table 6. CHLORINATION SYSTEM TESTS
7/14/72
Time
8:30a.m.
8:45
9:00
9:15
9:30
10:00
10:06
10:16
10:33
10:40
11:00
11:15
11:30
11:45
12:OON
10:00a.m.
10:06
10:16
10:33
10:00a.m.
10:06
DO (mg/1)
river shelter
7.15
7.05
7.20
7.10
7.15
Start
7.80
7.95
8.15
8.40
8.40
Start
Start
7.00
6.90
7.00
6.90
7.15
Average
Cl2 cycle
7.65
7.70
7.95
8.20
8.30
Average
C12 cycle
C12 cycle
— — — — ~^_ — «« i^ *_ «^_^__
DO
change
-0.15
-0.15
-0.20
-0.20
0.00
DO = 0.14
, rate = l.5#/day..
-0.15
-0.25
-0.20
-0.20
-0.10
DO = 0.18
, rate = 1.5#/day,
, rate = 1.5#/day
•
Temperature °C
river shelter
24.6
24.6
24.6
24.7
24.7
cycles/day
25.3
25.4
25.4
25.7
25.7
7/15/72
cycles/day
7/16/72
24.6
24.7
24.7
24.8
24.8
= 1
25.3
25.4
25.4
25.6
25.7
= 1
Chlorine (mg/1)
pH free total
shelter residual residual
7.95 0.0 0.20
7.63 9.2 10.60
7.85 0.2 0.50
7.95 0.0 0.05
8.02 0.0 0.1
7.52 9.1 9.8
7.88 0.2 0.6
7.78 0.0 0.1
9.3 10.2
Table 7.
CHLORINATION SYSTEM TESTS
7/17/72
Time
9:00a.m.
9:15
9:30
9:45
10:00
10:00
10:08
10:16
10:33
10:40
11:30
11:45
12:OON
12:15
12:30
DO
river
6.60
6.55
6.65
6.65
6.80
Start
7.30
7.35
7.55
7.70
7.75
DO
(mg/1) change
shelter (tng/1)
6.45
6.65
6.55
6.55
6.75
Average
Cl- cycle
£.
7.15
7.25
7.60
7.65
7.65
Average
-0.15
0.10
-0.10
-0.10
-0.05
DO = 0.06
, rate = 2#/day,
Changed to 4#/day
-0.15
-0.10
0.05
-0.05
-0.10
DO = 0.07
Chlorine (mg/1)
Temperature °C pH free total
river shelter shelter residual residual
23.4
23.3
23.3
23.4
23.4
cycles/day
C12 flow
23.7
23.7
24.1
24.4
24.4
23.5
23.6
23.6
23.6
23.7
= 1
tube
0.1 0.2
9.6 10.4
23.8
23.9
24.3
24.4
24.4
19
-------
Table 8. CHLORINATION SYSTEM TESTS
7/18/72
Time
8
9
9
9
9
10
10
10
10
10
11
11
11
11
12
:50a.m.*
:00
:15
:25
:35
:00
:06
:16
:35
:43
:00
:15
:25
:45
:00
DO (mg/1)
river shelter
7
7
7
7
7
.30
.40
.35
.45
.55
Start
8
8
8
9
9
.55
.70
.85
.20
.30
7.35
7.35
7.30
7.50
7.55
Average
C12 cycle
8.60
8.65
8.85
9.15
9.30
Average
DO
change
(mg/D
0
-0
-0
0
0
DO = 0
, rate =
0
-0
0
-0
0
DO = 0
.05
.05
.05
.05
.00
.00
2.5#/day,
.05
.05
.00
.05
.00
.01
Temperature °C
river shelter
24
24
24
24
24
.3
.5
.5
.6
.8
24
24
24
24
24
cycles/day =
25
25
25
26
26
.6
.6
.7
. 1
.0
25
25
25
26
26
.2
.4
.5
.6
.7
1
.5
.5
.7
.1
.0
Chlorine (mg/1)
pH free total
shelter residual residual
7.95 0.0 0.1
7.50 6.8 6.8
7.78 0.4 0.9
7.74 0.0 0.1
*Low pressure switch turned system off at 10:00 p.m., 7/17/72; system turned back on at 8:30 a.m.,
7/18/72.
10:00a.m.*
10:06
10:16
10:33
Table 9. CHLORINATION SYSTEM TESTS
7/19/72
Time
8:45a.m.*
9:00
9:15
9:30
9:45
10:00
10:06
10:16
10:33
10:39
10:45
11:00
11:15
11:30
11:45
DO
river
7.85
7.95
8.20
8.40
8.50
Start
9.55
9.75
9.95
10.10
10.45
DO
(mg/1) change
shelter (mg/1)
7.75
7.95
8.15
8.25
8.35
Average
C12 cycle
9.45
9.85
9.95
10.10
10.50
-0.10
0.00
-0.05
-0.15
-0.15
DO = 0.09
, rate = 3#/day,
-0.10
0.10
0.00
0.00
0.05
Temperature °C
river shelter
25.4
25.6
25.6
25.8
25.9
cycles/day
26.5
26.5
26.7
26.8
27.0
25.4
25.6
25.6
25.8
25.8
= 1
26.4
26.5
26.6
26.8
26.9
Chlorine (mg/1)
pH free total
shelter residual residual
•
8.10 0.0 0.2
7.49 7.0 7.5
7.98 0.3 0.7
8.09 0.2 0.2
Start
Average DO = -0.01
7/20/72
cycle, rate = 3#/day, cycles/day = 1
7.95
7.45
7.95
0.0
7.0
0.5
0.3
8.2
0.8
*Low pressure switch turned system off at 10:00p.m. the previous night, system burned back on at 8:30a.m.
20
-------
Table 10. CHLORINATION SYSTEM TESTS
8/8/72
Time
8: 50a.m.
9:05
9:20
9:35
9:50
10:00
10:06
10:16
10:33
10:43
11:10
11:25
11:40
11:55
12:10p.m.
1:00
DO (mg/1)
river shelter
7.40
7.25
7.35
8.00
7.60
Start
8.15
8.20
8.25
8.25
8.40
7.80
7.30
7.30
7.75
7.60
Average DO =
DO
change
(mg/1)
0.40
0.05
-0.05
-0.05
0.00
-0.07
C12 cycle, rate = 3#/day,
8.10
8.20
8.05
8.30
8.40
Average DO =
Cleaned first stage
-o.os
0.00
-0.20
0.05
0.00
0.04
Temperature °C
river shelter
21.1
21.0
21.1
21.2
21.2
cycles/day
22.0
22.2
22.2
22.5
22.8
21.6
21.6
21.5
21.7
21.7
= 2 '
22.5
22.6
22.7
22.8
23.0
Chlorine (mg/1)
pH free total
shelter residual residual
7.10 0.0 0.2
6.81 22.6 22.6
7.01 1.5 1.5
7.00 0.0 0.0
pump strainer
Table 11. CHLORINATION SYSTEM TESTS-
8/9/72
Time
8: 30a.m.
8:45
9:00
9:15
9:30
10:00
10:06
10:16
10:33
10:43
11:00
11:15
11:30
11:45
12:OON
DO
river
7:30
7.30
7.45
7.45
7.65
Start
8.15
8.15
8.30
8.30
8.55
(mg/1)
shelter
7.30
7.30
7.40
7.45
7.45
Average DO
C10 cycle,
z
8.05
8.10
8.20
8.25
8.50
Average DO
DO
change Temperature °C pH
(mg/1) river shelter shelter
0.00
0.00
-0.05
0.00
-0.20
= 0.05
rate = 2.5#/day,
-0.10
-0.05
-0.10
-0.05
-0.05
0.07
20.8
20.8
21.1
20.9
20.8
cycles/day
21.3
21.3
21.3
21.3
21.9
21.5
21.5
21.5
21.6
21.6
= 2
7.06
6.80
7.03
7.00
21.9
22.0
21.9
22.0
22.1
Chlorine (mg/1)
free total
residual residual
0.0 0.0
14.6 14.6
0.3 0.5
0..0 0.0
21
-------
Table 12. CHLORINATION SYSTEM TESTS
8/10/72
8
8
9
9
9
10
10
10
10
10
11
11
11
12
12
Time
:30a.m.
:45
:00
:15
:30
:00
:06
:16
:33
:43
:15
:30
:45
:OON
:15
DO
river
7
7
7
8
8
.80
.85
.95
.05
.25
Start
9
9
9
10
10
.50
.65
.85
.00
.15
(mg/1)
shleter
7.
7.
7.
8.
7
8
8
0
8.2
Average DO =
DO
change
(mg/D
-0
-0
-0
-0
-0
0
Cl- cycle, rate =
9.
9.
9.
9.
10.
Avera
55
60
75
90
20
,ge DO =
0
-0
-0
-0
0
0
.10
.05
.15
.05
.05
.08
3#/day,
.05
.05
.10
.10
.05
.03
Temperature °C pH
river shelter shelter
20.0 20
19 . 8 20
19.9 20
20.0 20
20.3 20
cycles/day = 3
22
22
22
22
22
.6
.5
.7
.7
.9
7.05
6.87
7.00
7.25
.0
.0
.1
.2
.4
Chlorine (mg/1)
free total
residual residual
0.0 0.1
16.8 17.2
0.6 1.1
0.0 0.1
22
-------
APPENDIX B
K>
%16H^LSL t.2-11 V2NPT
00Q1
DIFFUSER DETAIL
1-1/4
EXISTING PUMP BOLTS
BRACKET, 3REQ.
PUMP INTAKE ,-WELD
2 1/2x2
REDUCER
2x] REDUCING
COUPLING
1/2 ELBOW
AIR
RETURN FLOW
BUSHING
DIFFUSER
Figure 6. Air separator assembly
ASSEMBLY MOUNTED HORIZONTALLY
& ENCLOSED IN STRAINER WITH 1/16"
DIA. PERFORATIONS
ALL DIMENSIONS IN INCHES
HALF SCALE
-------
APPENDIX C
PARTS LIST
(SEE FIGURES 1,2, AND 3)
These products were used mainly as a matter of convenience for
evaluating the feasibility of automatic cleaning on small pumping systems.
Mention of trade names or commercial products does not constitute endorse-
ment or recommendation for use by the Environmental Protection Agency.
First Stage Pump
Second Stage Pump
Flow Meter
Prosser Industries, Inc.
Submersible Model 9-1312-4, 1 HP, Single
phase, 230 V.
- FMC Corporation, Peerless Dynaflo
Submersible, Model 4D100B-15-1, Single
phase, 230 V.
- Aeroquip Corporation, Barco Div.
a) Venturi Model 1 in. - 705,
b) Portable Master Meter Model M-56, 0-50
in. of water differential.
VV2
- Wm. Powell Company
a) Ball Valve "Star" l-l/4in.*
b) Electric Operator,* 115 V, 60 cy.
Cat. No. 4256
G1'G2
*1 in. ball valve with smaller electric
operator could have been used.
Capital Controls Co., Inc.
Plast-0-Matic Vacuum Shut off valve for
Model 201 Gas Chlorination System. Solenoid
operated.
- Marsh Instrument Company
Pressure gauge type 1., 2-1/2 in. dial,
dial range 60 Ib.
- Marsh Instrument Company
Pressure gauge type 1., 2-1/2 in. dial,
dial range 30 Ib.
24
-------
G4'G5
Chlorination System
Chlorine
FCV
(Flow Control Valve)
Air Separator
Water Line Sizes
24 Hour Timer
Cam Timer
Interval Timer
Marsh Instrument Company
Gauge type 3, compound, 2-1/2 in. dial,
dial range 30 in. x 30 Ib.
Capital Controls Co., Inc.
a) Gas chlorination system, Model 201
b) No. 15 nozzle, 0.56 in. orifice
c) Metering tube, Model A 108 (4 Ib/day).
Will Ross, Inc., Matheson Gas Products Div.
C12 MW 70.906 cylinder size 5, 15 Ib,
38 Ib gross wt.
Eaton Corporation, Dole Valve Div.
a) 5 gpm
b) 9 gpm.
In-house design (Figure 6, Appendix B)
Commercial air separators are also available.
a) Between first and second stage pumps--
1-1/4 in. x 200 ft long flexible plastic
pipe.
b) Between second stage pump and G]_--
1-1/2 in. x 300 ft long flexible plastic
pipe.*
c) Between Gj and G2--1-1/4 in. galvanized
pipe.
d) Between 62 and G3 (both directions)--
1 in. galvanized pipe.
e) Between Vj and 65 (both directions)--
1 in. galvanized pipe with exception that
ejector effluent tube is screwed into the
center tap of a 1-1/2 in. galvanized tee.
f) From 65 and extending for 300 ft toward
river--l-l/4 in. flexible plastic pipe.*
*These lines could be reduced one size.
International Register Co.
Intermatic Timer Model V37177
125 V, 60 Hz.
Singer Industrial Timer Corporation
Industrial Timer Type RC 7, 4 switch chassis,
single cycle with type A30 rear assembly.
Singer Industrial Timer Corporation
Automatic Reset Delay/Interval Timer
Model GP-30M, 115 VAC, 60 Hz.
25
-------
Delay - American Machine and Foundry Co.
Potter and Brumfield Div.
Time Delay Relay, solid state, Model CKB-38-
70010, Dwg. A. .1 to 10 sec. delay, 120 VAC.
Power Relay - American Machine and Foundry Company,
Potter and Brumfield Div.
General Purpose Relay, Type KRP5AG, 120 V,
'SPOT, 10 Amp.
Chlorine Shelter - Refer to Figure 3. Internal dimensions of
shelter are 22 in. wide x 18 in. deep x 32 in.
high. The shelter includes a large opening
in front with double door and padlock. The
walls and ceiling are insulated with 3-in.
fiberglass insulation. The base of the
shelter was mounted approximately 2-1/2 ft
above ground level. The roof is gabled and
covered with light gage metal. The entire
unit is painted with an all weather enamel.
26
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/4-78-010
3. RECIPIENT'S ACCESSION-NO.
.. TITLE AND SUBTITLE
AN AUTOMATIC CHLORINATION SYSTEM FOR ELIMINATING
BIOLOGICAL GROWTH IN PUMPING SYSTEMS FOR AUTOMATIC
INSTRUMENTATION
5. REPORT DATE
January 1978 issuing date
6. PERFORMING ORGANIZATION CODE
'. AUTHOR(S)
Richard P. Lauch
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Environmental Monitoring and Support Lab.
Office of Research 'and Monitoring
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
- Cin., OH
10. PROGRAM ELEMENT NO.
1BD612
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Same as above
13. TYPE OF REPORT AND PERIOD COVERED
In-House
14. SPONSORING AGENCY CODE
EPA/600/06
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Automatic chlorination was determined to be satisfactory for elimination
of microbial growth (slime) in monitor pumping systems. With chlorination,
changes in dissolved oxygen levels through the sampling system were minimized.
Optimum chlorine concentration and frequency of chlorine addition to the system
were determined during the period of maximum biological activity.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
COSATI Field/Group
Chlorination, Microorganism control,
Chlorinators
Automatic chlorination
system, Elimination of
biological growth in
pumping systems for
automatic instrumenta-
tion.
13B
3. DISTRIBUTION STATEMENT
Release to public
19. SECURITY CLASS (ThisReport)'
Unclassified
21. NO. OF PAGES
33
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
27
U.S. GOVERNMENT PRINTING OFFICE: 1978- 757-14O/6663
------- |