WATER POLLUTION CONTROL RESEARCH SERIES • WP-2O-22
Polymers
for
Sewer Flow Control
rj.S. DEPARTMENT OF THE INTERIOR • FEDERAL WATER POLLUTION CONTROL ADMINISTRATION
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WATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research Reports describe the results and
progress in the control and abatement of pollution of our Nation's Waters.
They provide a central source of information on the research, develop-
ment and demonstration activities of the Federal Water Pollution Control
Administration, Department of the Interior, through inhouse research and
grants and contracts with Federal, State, and local agencies, research
institutions, and industrial organizations.
Triplicate tear-out abstract cards are placed inside the back cover to
facilitate information retrieval. Space is provided on the card for the
user's accession number and for additional keywords. The abstracts
utilize the WRSIC system.
Water Pollution Control Research Reports will be distributed to requesters
as supplies permit. Requests should be sent to the Publications Office,
Department of the Interior, Federal Water Pollution Control Administration,
Washington, D. C. 20242
Previously issued reports on the Storm & Combined Sewer Pollution Control
Program:
WP-20-11 Problems of Combined Sewer Facilities and Overflows-
1967.
WP-20-15 Water Pollution Aspects of Urban Runoff.
WP-20-18 Improved Sealants for Infiltration Control.
WP-20-21 Selected Urban Storm Water Runoff Abstracts.
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Polymers
for
Sewer Flow Control
The Development and Demonstration of the Use of
Polymers to Reduce or Eliminate Sewer Overflows by
Flow Energy Reduction
FEDERAL WATER POLLUTION CONTROL ADMINISTRATION
DEPARTMENT OF THE INTERIOR
by
The Western Company
2201 N. Waterview Parkway
Richardson, Texas 75080
Program No. 11020 DIG
Contract No. 14-12-34
August, 1969
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FWPCA Review Notice
This report has been reviewed by the Federal
Water Pollution Control Administration and
approved for publication. Approval does not
signify that the contents necessarily reflect
the views and policies of the Federal Water
Pollution Control Administration.
ii
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ABSTRACT
Six water-soluble polymers were investigated to determine their
effects upon aquatic flora and fauna, flow characteristics of wastewater,
and the operation of a wastewater treatment plant.
It was found that the polymers and gels, in the magnitudes tested,
were not toxic to bacteria, algae, or fish, and did not act as a nutrient
for algae growth.
Based upon calculations obtained from flow test data, a maximum
flow increase of 2. 4 times the flow prior to injection could be obtained if
a constant head was maintained. Laboratory flow test data indicated that
if flow rates were held almost constant prior to and during polymer injec-
tion, a reduction in the static head occurred as a result of friction reduc-
tion within the fluid.
The most effective polymers in providing energy reduction were
Polyox Coagulant-701, WSR-301, andAP-30; however, AP-30 required
higher polymer concentrations to obtain equivalent flow characteristics.
In field tests on a 24-inch diameter line, it was found that poly-
mer concentrations of between 35 and 100 mg/1, decreased frictional flow
resistance sufficiently to eliminate surcharges of more than six feet.
Based upon an economic analysis, the average annual cost of new
construction was approximately five times the cost of using polymers dur-
ing peak storm-flow periods.
This report was submitted in fulfillment of Contract 14-12-34 be-
tween the Federal Water Pollution Control Administration and The Western
Company.
iii
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CONTENTS
Section Title
ABSTRACT ........ ......................... iii
LIST OF TABLES ....... ...... . ............ . . . . vii
LIST OF FIGURES ............................. i*
I PROJECT CONCLUSIONS AND RECOMMENDATIONS
Conclusions ..... ..... .................
Recommendations ....................... ^
II INTRODUCTION
Purpose of Project ..... „ .......... . ...... ^
Scope of Project ........................ ^
Project Objectives ....................... 9
III LABORATORY EVALUATION OF POLYMERS
Literature Survey .................... ... 1 1
Laboratory Model Tests .................. . . 12
Biological Testing of Effects of
Polymers on Aquatic Life ..... . ............ -^
Polymer-Nonsolvent Slurry System Study ........ 30
Effect of Polymers on Sewage ............... 33
IV FLOW TEST EVALUATION OF POLYMERS
Description of Flow Test Facilities ............ 47
Flow Test Procedure. . . .............. ..... 52
Chemical and Physical Characteristics
of Polymer-Sewage System ................ 56
Six-Inch Flow System Test Results ........... 61
Polymer Injection Point Test Results ........... 97
Effects of Solid Concentrations on Polymers ...... 97
V FIELD TEST EVALUATION OF POLYMERS
Large- Diameter Sewer Field Evaluation ......... 105
Wastewater Treatment Plant Tests ............ 130
VI ECONOMIC ANALYSIS OF POLYMER USE .............. 145
BIBLIOGRAPHY ...... . ....................... 155
APPENDICES
A FLUID FRICTION REDUCING POLYMERS LITERATURE SURVEY. 159
B DISCUSSION OF FLUID MODIFICATION BY POLYMERS ..... 163
v
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CONTENTS (Continued)
Section Title
C DERIVATION OF GRAPHS OF PERCENT FLOW
INCREASE VS POLYMER CONCENTRATION 170
D POLYMER SLURRY MIXING TECHNIQUES 179
vi
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TABLES
Table
I Preliminary Selection of Polymers li
II Water/Polymer Concentration Used in 0. 18-Inch Diameter
Test Line 13
III Biological Toxicity Test 25
IV Algae Toxicity Test 27
V Fish Toxicity Test 28
VI Percent Error in Viscosity Determinations 33
VII Sedimentation Capability of Polymers 39
VIII Biochemical Oxygen Demand (BOD) of Polymers 41
DC Affect of Polymers on Sludge Drying Beds 42
X Affect of Polymer on Sludge Drying Beds 43
XI Test Flow Parameters 47
XII Test Parameters and Ranges 51
XIII Flow Test Polymer Concentrations 54
XIV Restriction Test Polymers 55
XV Raw Sewage Characteristics of Dallas, Texas Area 57
XVI Physical and Chemical Characteristics of Polymer-Sewage
System 59
XVII Matrix of Flow Data Used 61
XVIII Test Line Manhole Instrumentation ni
XLX Polymer Injection Costs--Dollars Per Hour H5
XX Sewage Sample Analyses For 24-Inch Sewer Line
Tast Runs 125
XXI Results of 24-Inch Sewer Line Test Runs 126
XXII Initial Test Sites Investigated 131
Vll
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TABLES (Continued)
Table
XXIII Treatment Plant Slurry Components ................. 132
XXIV Treatment Plant Test -Run Sampling Times and Amounts .... 137
XXV Percent Removal of Applied Loading in Clarigester
Test Series 1 ..................... ......... 138
XXVI Lewisville Sewage Treatment Plant Studies Non-Polymer
Run ..................................... 139
XXVII Lewisville Sewage Treatment Plant Studies Polymer Run ... 139
XXVIII Percent Removal of Applied Loading in Clarigester Test
Series 2 .................................. 14°
XXIX Lewisville Sewage Treatment Plant Studies Non-Polymer
Run ..................................... 141
XXX Lewisville Sewage Treatment Plant Studies Polymer Run . . . 142
XXXI Lewisville Sewage Treatment Plant Studies Polymer Run ... 143
XXXII Lewisville Sewage Treatment Plant Studies Non-Polymer
Run ..................................... 144
XXXIII Keen Branch Contract Bid Tabulation ................ 148
XXXIV Keen Branch Relief Sewer Costs ................... 15°
XXXV Portable Injection Plant Costs ................... 151
XXXVI Estimates of Polymer Use ....................... 152
viii
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FIGURES
Number Title Page
1 Small Diameter Laboratory Flow Facility 14
2 Comparison of AP-30 Friction Reduction for Water
and Sewage (9 ml/1 Settleable Solids) at 6l°F in
0. 18-Inch Test Facility „ 15
3 Comparison of D-252 Friction Reduction for Water
and Sewage (9 ml/1 Settleable Solids) at 6l°F in
0. 18-Inch Test Facility 16
4
Comparison of FR-4 Friction Reduction for Water
and Sewage (9 ml/1 Settleable Solids) at 61 F in
0. 18-Inch Test Facility 17
5 Comparison of J-2FP Friction Reduction for Water
and Sewage (9 ml/1 Settleable Solids) at 6l°F in
0. 18-Inch Test Facility „ 18
6 Comparison of WSR-301 Friction Reduction for
Water and Sewage (9 ml/1 Settleable Solids)
at 61°F in 0. 18-Inch Test Facility 19
7 Comparison of Polyox Coagulant-701 Friction
Reduction for Water and Sewage (9 ml/1 Settleable
Solids) at 61°F in 0. 18-Inch Test Facility 20
8 Theoretical Growth and Death Rate of Bacteria ......... 23
9 a. Relationship of Initial Micro-Organisms to
Time, Based on an Arbitrary Time on the
Theoretical Growth and Death Curve 24
b. Affect of Nutrient Concentration Upon Growth
of Bacteria 24
c. Affect of Nutrient on Bacterial Count, With
Respect to Time 24
10 Growth of Micro-Organisms in Sewage and Polymer-
Sewage Material Including Nonsolvents Used 29
11 Growth of Algae in Sewage, and in Polymer-Sewage
Media 31
12 Degradation of Polymers in Slurries 34
13 Sludge Drying Test Beds 37
IX
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FIGURES (Continued)
Number Title Page
14 Sedimentation Capabilities of Polymer, Based on
Percent Increase of Net Sewage Value .............. 38
15 Sedimentation Capabilities of Polymer on Settleable
Solids .................................... 40
16 Affects of Polymers (at Different Concentrations)
on Moisture Content of Sludge .................... 44
17 Affect of Polymers (at Different Concentrations)
on Total Solids Content of Sludge .................. 45
18 Affect of Polymers (at Different Concentrations)
on Volatile Solids Content in Sludge ................ 46
19 Six-Inch Diameter Flow Test Facility ................ 49
20 Four-Inch Flow System Schematic Diagram ............ 53
21 Comparison of the Effectiveness of Six Additives
in Water as a Function of Temperature ............... 63
22 Comparison of the Effectiveness ofWSR-301 at
200 mg/1 in Sewage as a Function of Temperature ....... 64
23 Comparison of the Effectiveness of Polyox Coagulant-
701 at 100 mg/1 in Sewage as a Function of Temperature ... 65
24 WSR-301 at 200 mg/1 in Sewage at Indicated
Temperatures, Six-Inch Test Facility ............... 66
25 Polyox Coagulant-701 at 100 mg/1 in Sewage
at Indicated Temperatures ....................... 67
26 AP-30 in Six- Inch Test Facility at 38°F
27 AP-30 in Six-Inch Test Facility at 70°F .............. 69
28 AP-30 in Six-Inch Test Facility at 90°F .............. 70
29 FR-4 in Six-Inch Test Facility at 38°F ............... 71
30 FR-4 in Six-Inch Test Facility at 71°F .............. 72
31 FR-4 in Six-Inch Test Facility at 90°F ............... 73
x
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FIGURES (Continued)
Number Title Page
32 D 252 in Six-Inch Test Facility at 38°F 74
33 D 252 in Six-Inch Test Facility at 70°F 75
34 D 252 in Six-Inch Test Facility at 90°F 76
35 J-2FP in Six-Inch Test Facility at 72°F 77
OT
36 WSR-301 in Six-Inch Test Facility at 38 F in Water
78
37 WSR-301 in Six-Inch Test Facility at 70 F in Water
°F in Water 79
OT
38 WSR-301 in Six-Inch Test Facility at 90 F in Water
80
39 WSR-301 in Six-Inch Test Facility at 38 F in
Sewage (3 ml/1 Settleable Solids) 81
40 WSR-301 in Six-Inch Test Facility at 70°F
in
Sewage (3 ml/I Settleable Solids) 82
41 WSR-301 in Six-Inch Test Facility at 90°F
in Sewage (3 ml /I Settleable Solids) .............. 83
42 WSR-301 in Six-Inch Test Facility at 38°F
in Sewage (9 ml /I Settleable Solids) ............... 84
43 WSR-301 in Six-Inch Test Facility at 70°F
in Sewage (9 ml /I Settleable Solids) ............... 85
44 WSR-301 in Six-Inch Test Facility at 90°F
in Sewage (9 ml /I Settleable Solids) ............... 8b
45 Polyox Coagulant-701 in Six-Inch Test Facility
at 38°F in Water ............................ b7
46 Polyox Coagulant-701 in Six-Inch Test
Facility at 73°F in Water ...................... 8b
47 Polyox Coagulant-701 in Six-Inch Test
Facility at 90°F in Water
48 Polyox Coagulant-701 in Six-Inch Test Facility
at 38°F in Sewage (3 ml /I Settleable Solids) .......... 90
49 Polyox Coagulant-701 in Six-Inch Test Facility
at 73°F in Sewage (3 ml /I Settleable Solids) .......... 91
XI
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FIGURES (Continued)
Number Title Page
50 Polyox Coagulant-701 in Six-Inch Test Facility
at 90°F in Sewage (3 ml/1 Settleable Solids) 92
51 Polyox Coagulant-701 in Six-Inch Test Facility
at 38°F in Sewage (9 ml/I Settleable Solids) 93
52 Polyox Coagulant-701 in Six-Inch Test Facility
at 73°F in Sewage (9 ml/I Settleable Solids) 94
53 Polyox Coagulant-701 in Six-Inch Test Facility
at 90°F in Sewage (9 ml/I Settleable Solids) 95
54 Injection Point Affect on Sewage System Flow
Constrictions 98
55 Percentage Flow Increase vs Sewage Concentration
(mg/1) Polyox Coagulant-701 Polymer 100
56 Percentage Flow Increase vs Sewage Concentration
(mg/1) WSR-301 Polymer 101
57 Polymer (mg/1) vs Percent Increase With a Given
Sewage Concentration, Polyox Coagulant-701 Polymer .... 102
58 Polymer Concentration (mg/1) vs Percentage Flow
Increase With Given Sewage Concentration, WSR-
301 Polymer 103
59 Plan and Profile of 24-Inch Sanitary Sewer 106
60 Monitoring Manhole 107
61 Water Level Recorder 108
62 Fluorometer 109
63 Fluorometer Recorder . 109
64 Dye Metering Pump 110
65 Slurry Mixing Tank Ill
66 Injection Unit. 112
67 Field Injection System With List of Parts 113
68 Injection Manhole Cover at Manhole "A" 114
xii
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FIGURES (Continued)
Number Title Page
69 Units in Operation at Manhole "A" 114
70 Head Reduction Obtained Using 80 mg/1 of WSR-301 .... 119
71 Hydrograph of Flow and Surcharge of Monitoring
Manholes Before, During, and After Injecting
Polyox Coagulant-701 121
72 Hydrograph of Flow and Surcharge of Monitoring
Manholes Before, During, and After Injecting
Polyox Coagulant-701 123
73 Lewisville Wastewater Treatment Plant Layout 133
74 Schematic of Slurry Injector System Used for
Treatment Plant Tests 134
75 Sewer Line Location Used in Cost-Benefit
Analysis in Garland, Texas 146
xiii
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SECTION I
PROJECT CONCLUSIONS AND RECOMMENDATIONS
Conclusions
From the literature study of potential water-soluble polymers, six
candidates were selected for evaluation in the laboratory and six-inch
sewer line test facility.
Trade Name
Poly ox Coagulant-701
WSR-301
AP-30
D252
FR-4
J-2FP
Supplier
Union Carbide
Union Carbide
Dow Chemical
Calgon Corp.
Hercules Corp.
The Western
Company
Unit Cost-H-
$/lb.
1.45
0.80
2. 15
1.25
1.60
0.40
Chemical Class
Polyethylene Oxide
Polyethylene Oxide
Copolymer (Aerylate/
acrylamide)
Copolymer (Acrylate/
acrylamide)
Copolymer (Acrylate/
acrylamide)
Galactomannan
-H- The unit costs are for less than 2,000 pound quantities, April, 1969.
Variable unit cost reductions are available on larger quantities.
Although flow studies indicated that Polyox Coagulant-701 and
WSR-301 provide maximum friction reduction when suspended in a gelled
slurry and injected into water, each potential polymer candidate and slurry
nonsolvent (isopropyl alcohol or cellosolve) was tested to determine what
affect each had upon bacteria, fish, and algae. Tests conducted indicate
that the polymers and nonsolvents are not detrimental to bacteria growth
and, therefore, will not disrupt the biological treatment of sewage in
wastewater treatment plants. Tests conducted on algae in a polymer envi-
ronment indicated that the polymers have no toxic and only nominal nutrient
affects. The fish bio-assay indicated that in a polymer slurry concentra-
tion of 500 mg/1, some fish deaths resulted; however, flow tests indicated
that polymer slurry concentrations above 250 mg/1 provide no additional
flow benefits, and therefore, 500 mg/1 polymer concentrations would not
be required in actual pollution control applications. Thus, indications
are that the use of the above polymers and polymer slurries as friction
reducers in municipal sewers will not produce fish kills in the receiving
lake or stream.
After determining that the selected polymers were not toxic to
aquatic flora and fauna, each polymer was tested in the six-inch sewer
line facility to determine flow characteristics while maintaining a constant
flow rate. The polymers ranked in the order presented above with respect
to derived percent flow increase at a constant pressure head (see Appendix
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C for example of how flow increase was derived). The maximum derived
flow increase was about 2.4 times the flow prior to injecting a polymer
slurry. The following data indicate the calculated percent flow increase,
based on data obtained at a constant flow rate of 300 gpm and a polymer
concentration of 200 mg/1 or ppm by weight.
Polymer
P. C.-701
P. C.-701
P.O. -701
WSR-301
WSR-301
WSR-301
AP-30
AP-30
AP-30
D252
D252
D252
FR-4
FR-4
FR-4
(1)
Temperature
°F
38
73
90
38
70
90
38
70
90
38
70
90
38
71
90
Derived (2)
Flow
Increase
144
136
146
138
117
133
114
100
104
26
22
27
24
36
24
Ratio of
Final-to-
Initial Flow
2.44
2. 36
2.46
2. 38
2. 17
2. 33
2. 14
2.00
2.04
1. 26
1. 22
1.27
1. 24
1.36
1.24
J.2FP 72 12 1.12
(1) P. C. is abbreviation for Polyox Coagulant.
(2) Percent flow increase = Flow with Polymer - 300 gpm x 100
300 gpm
The two polyethylene oxides, WSR-301 and Polyox Coagulant-701
were most effective in reducing friction losses; however, small-scale
laboratory work indicated that both polymers' friction-reduction abilities
were reduced in a sewage media when compared with water. Therefore,
tests using various sewage concentrations and temperature variations
were conducted in the six-inch test facility. Typical results of these
tests, conducted at a constant flow rate of 300 gpm and a polymer con-
centration of 200 mg/1 or ppm by weight, are presented below:
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Polymer
Sewage
Concentration
ml II of
Settleable
Solids
WSR-301
WSR-301
WSR-301
WSR-301
WSR-301
WSR-301
P. C. -701
P. C. -701
P. C. -701
P. C. -701
P. C. -701
P. C. -701
3
3
3
9
9
9
3
3
3
9
9
9
Sewage
Temperature
38
70
90
38
70
90
38
73
90
38
73
90
Derived
Flow
Increase
105
97
94
125
135
109
103
110
117
127
142
117
Ratio of
Final-to-
Initial Flow
2.05
1.97
1.94
2.25
2.35
2.09
2.03
2. 10
2. 17
2.27
2.42
2. 17
These results show that the temperature and sewage concentration
(settleable solids) should be considered prior to selecting a polymer addi-
tive. Additional tests on these two polymers at higher sewage concentra-
tions also verify this requirement, as indicated by the following data:
Polymer
WSR-301
WSR-301
WSR-301
WSR-301
P. C. -701
P. C. -701
Sewage
Concentration
mlII of Sewage
Settleable Temperature
Solids °F
46
68
100
115
44
85
70
70
70
70
70
70
Derived
Flow
Increase
140
88
79
56
126
109
Ratio of
Final-to-
Initial Flow
2.40
1.88
1.79
1.56
2.26
2.09
In particular, consideration should be given to the polymer AP-30
when the above factors (temperature and settleable solids) are in the range
of 70 ml/1 and 70°F. The AP-30 polymer was found to be relatively stable
over the temperature range of 38°F to 90°F, and relatively unaffected by
sewage concentration; however, the cost and higher polymer concentration
(250 mg/1 as compared with 200 mg/1 of WSR-301 and 100 mg/1 of Polyox
Coagulant-701 to achieve similar flow characteristics) required by AP-30
should be considered in its use. Also, polymer FR-4 was not affected by
sewage, but was not as effective in providing friction reduction as polymers
shown in the above data.
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Polymer D252 was less effective than Polyox Coagulant-701,
WSR-301 andAP-30 in reducing frictional flow losses; however, because
of the tendency of this polymer to form a cohesive mass when dispersed
in water (although suspended in a nonsolvent gel), it was replaced in
performance order by FR-4, which has very similar flow characteristics.
Polymer J-2FP required from two to five times the concentration
required for the other polymers tested. Although this polymer costs less,
the cost difference was not sufficient to overcome its inefficiency.
Limited tests were conducted in which Polyox Coagulant-701,
WSR-301, AP-30, and FR-4 were used to determine what effect a polymer
slurry injection point location had relative to relieving a flow constriction.
Test results indicated that the polymer slurry should be injected upstream
and near the pipe constriction.
Sludge drying tests were also conducted on the selected polymers
to determine if the polymers affected drying rate (see Table IX and Figure
16). It was found that during the first four to six days of drying, the
moisture content of the sludge and polymer mixtures exceeded that of
sludge alone; however, the moisture content at the end of 28 days was
about 10 percent less in the mixture of sludge and polymer, indicating
that, by using polymers, the time sludge must remain on drying beds
prior to removal and disposal can be reduced.
The biochemical oxygen demand (BOD) of polymers has no signif-
icant affect upon the BOD of sewage; however, an increase in chemical
oxygen demand (COD) was measured as polymer concentration increased,
as shown in Table XVI.
The two most effective friction reducers, the polyethylene oxides,
were water soluble and required thorough dispersion of the individual
polymer particles during initial contact with water. The most effective
technique for obtaining this dispersion was the predispersion or suspen-
sion of polymers in a gelled nonsolvent. The nonsolvents tested for toxicity
were cellosolve and isopropyl alcohol. Data indicated that, for the concen-
trations tested (maximum concentration was 500 mg/1), significant toxicity
effects were not observed. Both nonsolvents were used in the test phases
and no advantage of either over the other was apparent; however, cello-
solve's cost is slightly higher, $1. 12 per gallon as compared with $0.69
per gallon for isopropyl alcohol.
The nonsolvent was gelled by adding klucel H (supplied by the
Hercules Corp. at $1. 30 per pound for small quantities), which is a water-
soluble cellulose ether powder. The technique used in obtaining a gel is
described in Appendix D.
After the gel was formed, the polymer was added slowly, about 120
pounds of polymer each 20 minutes, while the gel was circulated through
the specially designed batch tank, resulting in a suspended polymer slurry.
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The weight proportions generally used in making the slurry were
69. 25 percent nonsolvent, 0. 75 percent gelling agent, and 30.00 percent
polymer. Slurries were also made by using 40 percent polymer; however,
this percentage was the maximum polymer content that would remain in
suspension. Also, the gelling agent was reduced to 0. 5 percent for a 40
percent polymer concentration.
To obtain dispersion in water, the slurry was injected (metered by
a valve and flow meter) into the sewage by an eductor which provided ex-
treme turbulence and mixing. This method was found to be efficient, and
the equipment required was inexpensive. To operate the eductor, sewage
was pumped from the sewer line through the eductor and the sewage and
slurry were then returned to the line.
Tests were conducted by using the two most efficient polymers to
observe their effects upon a 24-inch sewer line which was frequently sur-
charged as much as six feet. Test results showed that a decrease in en-
ergy or static head on the line occurred after polymer was injected into
the line, although the volume of flow carried by the pipe increased or var-
ied only slightly.
It should be noted that the primary purpose of the test was not to
determine the percent flow increase that could be obtained, but to deter-
mine if each polymer provided sufficient friction reduction to eliminate
surcharged conditions. Both of the polymers tested eliminated surcharges;
however, lower polymer concentrations required longer time periods to
obtain the same head reduction that was obtained at the higher polymer
concentrations.
The time required to obtain head reduction is also dependent upon
the length of line and upstream conditions (amount of sewage accumulated
within system which, in effect, serves as a reservoir). It is apparent,
therefore, that potential trouble areas within a system should be monitored
and polymer injected at low concentrations to maintain the flow within the
pipe rather than delay injection until overflow conditions are evident. Such
a monitoring system could be made to operate automatically by a level de-
tection system which actuates pump motors and valves of the injection
equipment.
Limited test data obtained from investigations conducted on a
wastewater treatment plant indicated no definite improvements in the fil-
tration and sedimentation rates. Also, no adverse effects upon the treat-
ment process were observed.
Recommendations
It is recommended that the project's results and the potential
polymer uses for eliminating surcharged flow conditions be made available
to the city public works officials, city engineers, consulting engineers,
plant engineers of industry, and various health officials, so that additional
applications for polymer use will be investigated and additional full-scale
tests conducted to supplement the known data.
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To avoid the expense of using a slurry to obtain hydration of the
polymer particles, investigations should be conducted into methods of
modifying polymers to permit dry feeding directly into the wastewater.
Additional studies should be conducted to determine the degra-
dation effects of mechanical agitation, such as occur in pumps, upon
polymer chains (see Appendix B). Also, the degradation effects of polymers
flowing through pipelines over long distances should be investigated.
Polymer chain scission will result in a reduction in the aqueous solution's
viscosity and affect its friction-reduction capability.
The efficiency of various polymer concentrations in large-diameter
(30 inches and greater) pipes is not known, as explained in Appendix B.
Projects using polymers in such pipes should be conducted to determine
characteristics of flow and efficiency.
The applicability of polymers to force mains from sewage lift
stations should be investigated. Results reported on this program in-
dicated that polymers could increase the capacity of pumping units by
reducing the total system head as a result of friction loss reductions.
Also, by maintaining the same total dynamic head on a system, line
capacities could be increased to prevent sewage bypasses during peak
flow periods.
The effect of polymers on flow conditions in various conduit
cross-section configurations should be studied.
Studies -- including full-scale sludge drying studies -- should
be conducted to determine what influence friction-reducing polymers
have on filter-rock biota and the activated sludge treatment process.
The effects of various industrial wastes upon the friction reduction
capabilities of polymers should be determined.
An actual flow-test program should be conducted over a period
of several months to determine the effectiveness of this technique to
prevent pollution of natural water systems, and to obtain actual operational
expense of the technique.
Additional mechanical equipment should be investigated to accom-
plish both slurry injection and dry feeding of polymer.
Finally, periodic investigations should be conducted to evaluate
new potential friction reducing materials and existing polymer improvements.
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SECTION II
INTRODUCTION
Purpose of Project
Since 1956, when Congress enacted the Federal Water Pollution
Control Act, (amended in 1961, 1965, and 1966), an increased effort has
been made nationally to eliminate water pollution and restore our natural
water systems to a desired quality standard. To achieve this goal, im-
proved and more effective methods of treating industrial and domestic
wastewater are being investigated and developed; however, the develop-
ment, construction, and effective operation of better treating facilities
cannot prevent the continued pollution of our waters from overflows of
wastewater resulting from surcharged flow conditions in sewage collection
systems.
A potential method for controlling this source of pollution is the
technique of using high molecular weight polymers to reduce frictional
resistance to flow. This reduction lowers the energy (static head, in a
gravity flow system) required to drive the wastewater. So, by maintain-
ing a constant energy level (or head), increased flow capacity can be ob-
tained with the use of such polymers in existing sewer pipe.
This technique is applicable to both combined and separate sewer
lines during both wet- and dry-weather surcharges.
An understanding of the extent and magnitude of urban wastewater
overflows and surcharges has been amplified by recent studies. Combined
sewers are used by 29 percent of the sewered population of the United
States--eight states apparently have no combined sewers in use at this
time (Reference 1). The feasibility of separating combined sewers is com-
plicated by cost (estimated on a national basis, per capita cost is $835)
and by the areas served, i. e. , those areas with greatest population den-
sities and commercial activities (Reference 1).
In those areas in which combined sewers do not present problems,
overflows resulting from ground-water infiltration and dry-weather over-
flows (caused by insufficient line capacity) produce hazards to public
health.
The solution to the above pollution problems has been approached
by investigating new or improved techniques and ideas of flow containment
(control, treatment, and combinations of control and treatment).
This report describes and presents the results of a Federal Water
Pollution Control Administration sponsored research project which investi-
gated and demonstrated one method of containing and controlling flow with-
in sewer collection systems--the use of fluid flow friction-reducing poly-
mers. Other methods of flow control and containment currently being inves-
-------
tigated by others include a pressure sewer line within an existing combined
sewer, a system to divert stormflow to an external storage system and later
return to the system, means of modifying plumbing fixtures and system de-
sign, means of reducing ground-water infiltration, systems of internal stor-
age and later discharge, and ways to control land use.
Scope of Project
In the development and demonstration of the use of water-soluble
polymers for reducing frictional losses within sewer pipes, potential ad-
verse or toxic affects of both polymers and polymer nonsolvents on the
aquatic flora and fauna of streams and treatment plants were investigated.
The selection of polymers to be investigated was based upon a study of 1)
the literature describing their characteristics and properties, 2) The West-
ern Company's experience in effective use of polymers, 3) the investiga-
tions and research reported by others and 4) small-scale laboratory flow
tests. Based on the study of available polymers and preliminary flow tests
and using specific criteria for selection, six polymers were used to deter-
mine the extent of flow increase each caused in a sewage conveyance
system, and if each was compatible with the sewer environment.
While determining that the selected polymers and nonsolvents were
compatible with a stream and sewage environment, extensive flow tests
were conducted on a specially designed six-inch sewer line test facility.
These tests were conducted by using various polymers and polymer concen-
trations in both water and sewage to determine the effects of sewage con-
centrations, as measured by settleable solids, upon the effectiveness of
the polymer and polymer concentration to reduce frictional resistence to
flow.
Flow tests were also conducted to determine the optimum location
relative to a surcharge for injecting polymer to eliminate various flow con-
strictions. Also, flow tests were conducted in a large-size sewer to de-
termine actual installation results and information relative to the flow of
wastewater in sewers containing polymers.
As part of this installation test, equipment was designed and fabri-
cated to disperse the polymers into sewage.
Finally, a cost-benefit analysis was made to provide an economic
measure of the value of using friction-reducing polymers in a sewer sys-
tem.
The program scope also included tests on a wastewater treatment
plant to determine what affect the polymers would have on 1) the settling
of solids, 2) the trickling filter and 3) sludge drying rates. These tests
were conducted in a plant which contained a clarigester (mechanized
clarifier superimposed over a mechanized digester with a concrete tray
between the two compartments--a variation of the Imhoff tank), a high-
rate trickling filter, a sludge drying bed, and an oxidation lagoon (which
served as a final clarifier).
-------
Project Objectives
The primary objectives of this project were the selection of non-
toxic, water-soluble polymers that produce reductions in frictional losses
in wastewater, the development of an injection device and method of poly-
mer injection, the demonstration of the economic feasibility of polymer
use, and the determination of what affects the polymer and polymer slurries
have on the operating characteristics of a wastewater treatment plant.
The secondary objective in selecting the best polymer for reducing
friction losses in wastewater was to screen potential polymer candidates,
based upon friction-reduction capability, sludge-drying characteristics,
and toxicity to aquatic life, such as bacteria, algae, and fish.
The secondary objective in developing an injection device was to
minimize equipment cost, size (for mobility) and operation and maintenance
complexity.
The secondary objective in demonstrating the feasibility of inject-
ing polymers was to reduce the static head on a surcharged line while min-
imizing the time required for head reduction to occur and the polymer con-
centration required to obtain the desired flow condition.
The secondary objective of the wastewater treatment plant test was
to determine the affect polymers would have on detention time and removal
of settleable solids, as well as the affect the polymers have on the trickl-
ing filter operation and on sludge characteristics.
-------
SECTION III
LABORATORY EVALUATION OF POLYMERS
Literature Survey
As the first step in the program to determine the best polymer addi-
tives to use, a literature survey was conducted for the purpose of finding
determinative information that could be used in the selection process of
potential water-soluble polymers capable of providing friction reduction
properties to sewage flow in a closed conduit. The following criteria were
used for selecting water-soluble polymers for evaluation.
Friction-reduction capability. Toxicity to biological systems.
Solubility in water. Flocculating and settling
High molecular weight. characteristics.
Hydration (solubility) rate. Availability from commercial
Shear stability in flow systems. sources.
Storage life. Cost.
Further screening was then accomplished by evaluating the appli-
cability of the additives to this particular program, based upon the con-
tractor's experience, the experience of manufacturers of polymers, and
consultation with the staff of the Federal Water Pollution Control Admin-
istration.
The principal sources of information used for the investigation were
Chemical Abstracts, bulletins from commercial suppliers, and reports
written by The Western Company and others (Appendix A).
Additives selected for further investigation as possible friction
reducers (as a result of the literature survey) are listed in Table I.
Application of the screening criteria to the above additives resulted
in the following six being selected for evaluation in the laboratory and in
the six-inch model test facility: 1) Polyox Coagulant-701, 2) WSR-301,
3) AP-30, 4) FR-4, 5) D252, and 6) J-2FP. Each of these additives appeared
to have specific advantages that resulted in its selection.
1) Polyox Coagulant-701 has a very high molecular weight (approx-
imately 7 x 106) and produces a highly viscoelastic solution in water when
added in relatively small quantities. This polymer is basically a flocculent
which aids in the sedimentation process when and if it reaches a treatment
plant. Also, it is generally lower in price than many other polymers inves-
tigated.
2) WSR-301 has essentially the same advantages as Polyox Coagu-
lant-701, except that its molecular weight is approximately half that of
701. It, too, is low in cost when compared with other polymers considered.
11
-------
TABLE I
PRELIMINARY SELECTION OF POLYMERS
Trade Name
Supplier
Chemical
1-DSM-50C
WSR-301
Polyox Coagulant 701
Polyox F.R.A.
K-PAM
Superfloc 16
D-252
AP-30
J-2FP
CMC-7H
FR-4
CMHEC-37M
Gafloc C-61
Gentrez AN-169
Union Carbide
Union Carbide
Union Carbide
Union Carbide
American Cyanamid
American Cyanamid
Calgon Corporation
Dow Chemical
The Western Company
Hercules Corporation
Hercules Corporation
Hercules Corporation
General Aniline
General Aniline
Polyethylene oxide
Polyethylene oxide
Polyethylene oxide
Polyethylene oxide
Poly a cry la mide
Polya cry la mide
Copolymer (acrylate/
a cry a mide)
Copolymer (acrylate/
acryamide)
Galactomannan
Copolymer cellulose
Copolymer (acrylate/
acryamide)
Carboxymethylhydroxy-
ethyl cellulose
Copolymer (methyl-
vinyl ether/maleic
anhydride)
3) AP-30, based upon experience and data, had shown to be an
excellent-flow- increasing additive.
4) FR-4, again based upon experience, was known to behave essen-
tially the same as AP-30 in flow systems.
5) D252, characteristically like FR-4 and AP-30, was selected
because, in powder form, it is manufactured in disc-like shapes, which
greatly inceases its solubility rate in water.
6) J-2FP is low cost, has shear stability and, unlike the other five
synthetic polymer additives, it is a natural polymeric material.
Laboratory Model Tests
After the best potential polymers were selected, each was flow
tested to determine its capabilities. Tests were conducted in a 0. 18-inch
internal diameter tube to determine flow behavior of sewage/polymer solu-
tions and sewage only. The small-scale tests were inexpensive and less
time consuming than large-scale tests. Results of these small-scale tests
provided the basis for the six-inch test line program.
12
-------
An existing small-scale flow test rig, available in The Western
Company's flow test laboratory, was utilized. This flow equipment (Figure
1) consisted of an air reservoir, a nine-gallon liquid reservoir, a temper-
ature indicator, a five-foot test section of 0. 18-inch internal diameter
tubing, a differential pressure gage and a flow measuring device. With such
a test rig, the shear on the polymer is minimized because it was energized
with air rather than by mechanical means (thereby creating essentially the
same condition that exists in a gravity sewer line) once the sewage/polymer
solution is injected into the sewage flow. This test rig has been used for
polymer evaluation on several in-house programs and on prior research
contracts with the Naval Ordnance Test Station (Pasadena) and the David
Taylor Model Basin. The credibility of the test device was established
under these programs, which therefore, instilled a high degree of confidence
in the data obtained for this program.
Tap-water friction tests were performed by using the facility to es-
tablish base data. A sewage containing nine-miiiiliter per liter settleable
solids content was then made up in sufficient quantity so that sewage data
could be determined for comparison with water data. The sewage was "man-
ufactured" by diluting raw sludge with tap water in 35-gallon drums to give
the desired settleable solids content.
The behavior of each selected polymer, at different concentrations,
in tap water was determined to establish additional base data. Each water-
polymer solution was allowed to hydrate approximately four hours before
testing in the 0. 18-inch rig. Polymer concentrations tested are shown in
Table II.
TABLE II
WATER/POLYMER CONCENTRATION
USED IN 0. 18-INCH DIAMETER TEST LINE
Concentration Concentration
Polymer (ppm) Polymer (ppm)
AP-30
FR-4
D252
10
10
10
&
&
&
100
100
100
J-2FP
WSR-301
Poly ox
Coagulant
701
50
10
10
, 250 &
& 100
& 100
1250
The above test procedure was then repeated by using a sewage con-
centration of nine-milliliter per liter settleable solids (instead of tap water)
and the polymer concentrations shown in Table II. This data was then
compared with the water/additive data.
The data obtained from the tests performed in the small-scale flow
facility are shown in Figures 2 through 7. Test data shown for the tap
water/additive and the sewage/additive regimes compare flow behavior
in each system.
13
-------
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Figure 2. Comparison of AP-30 Friction Reduction for Water and Sewage
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15
-------
PRESSURE DROP, psi/IOOFEET
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Figure 3. Comparison of D-2^2 Friction Reduction for Water and Sewage
(9 ml/1 Settleable Solids) at 6l°F in 0. 18-Inch Test Facility.
16
-------
1000
VELOCITY , FEET /SEC
100
Figure 4. Comparison of FR-4 Friction Reduction for Water and Sewage
(9 ml/1 Settleable Solids) at 61 F in 0. 18-Inch Test Facility.
17
-------
1000
10
VELOCITY, FEET/SEC
100
Figure 5. Comparison of J-2FP Friction Reduction for Water and Sewage
(9 ml/1 Settleable Solids) at 6l°F in 0. 18-Inch Test Facility.
18
-------
1000
I K)
VELOCITY , FEET / SEC.
Figure 6. Comparison of WSR-301 Friction Reduction for Water and Sewage
(9 ml/1 Settleable Solids) at 6l°F in 0. 18-Inch Test Facility.
'
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Figure 7. Comparison of Polyox Coagulant-701 Friction Reduction for
Water and Sewage (9 ml/1' Settleable Solids) at 6l°F in
0. 18-Inch Test Facility.
;:
-------
The sewage behaved Theologically (flow and viscosity), the same
as water without additives. Consequently, a pressure drop per unit length
A P \ versus velocity (V) plot of the data could be used to determine
L j the affect of sewage on the additive as far as its friction-reduc-
tion ability was concerned.
A comparison of water/polymer with sewage/polymer data for AP-
30, D252, and FR-4 (Figures 2, 3 and 4) showed no interference by the
sewage on friction-reduction ability of the polymers. Since these three
additives are aery late /acrylamide type co-polymers, it would be expected
that if one was not affected, the others would not be.
J-2FP, WSR-301 and Polyox Coagulant-701 showed a polymer/sew-
age interaction in the small-scale testing which was, to different degrees,
slightly deleterious to their friction-reduction effect. Figures 5, 6 and 7
show the friction comparison of water/polymer with sewage/polymer data
for J-2FP, WSR-301 and Polyox Coagulant 701, respectively; however, the
deleterious effect of the sewage on friction reduction remains constant as
the polymer concentration is increased; thus, it was concluded that a con-
stant amount of the polymer was affected regardless of polymer concentra-
tion.
Biological Testing of Affects of Polymers on Aquatic Life
While flow tests were being conducted on the six selected polymers,
toxicity and other affects upon bacteria, algae, and fish were determined
by using standard methods (or accepted methods in specific instances).
Purpose of Tests. Since sewage is biologically decomposed in sew-
age treatment plants, it is desirable that the presence of polymers at vary-
ing concentrations not be detrimental to the bacteria in the collection and
treatment systems. Therefore, toxicity tests (of polymers and polymer
slurries toward sewer organism) were started early in the program.
Storm water from heavy rain results in surcharges and/or overflows
in separate as well as combined sewers, as does infiltration, illegal con-
nections, and insufficient line capacity. This wastewater is often com-
pletely or partially bypassed at the treatment plant and directly discharged
into a lake or stream. The use of polymer injection to alleviate the sur-
charge condition in sewers must not extensively contribute to the pollution
problems of these discharges, or cause fish kills, bacterial death or algae
blooms. Therefore, polymers and polymer slurries affect upon algae and
fish were also investigated.
Bacteria Test and Analysis Procedure. Random seed samples of raw
sewage were taken from the Rowlett Creek sewage treatment plant, located
in the City of Garland, Texas. A portion of the raw sewage was diluted
1:100 with distilled water. From this dilution, 1 milliliter was transferred
to a sterilized petri dish containing 10 milliliters of nutrient agar. Three
samples were prepared in this manner for a control group, then incubated
at 37°C for 24 hours. After 24 hours, a bacterial plate count was made.
Subsequent counts were made at selected time intervals to determine
21
-------
bacterial growth and death pattern in the sewage, which was controlled as
described below for the polymer-sewage mixtures.
To evaluate the toxic effect of polymers on bacteria, two 200-
milliliter Erlenmeyer flasks were filled with 100 milliliters of sewage, and
a polymer added to achieve the desired polymer concentration. The polymer
concentrations were evaluated at 100 and 500 milligrams per liter, which
gave an upper and lower limit for evaluation. The tests were conducted at
2 C and 29. 5°C in the constant-temperature bath. The Erlenmeyer flasks,
containing polymer and sewage, were placed in the constant temperature
bath and agitated at the rate of 85 strokes per minute to simulate movement
in a sewer line. At fixed intervals after initial mixing, 1-milliliter samples
were withdrawn from the flask and 1:100 dilutions were made with distilled
water. Samples of 1-milliliter were withdrawn from the 1:100 dilution and
transferred to the nutrient agar in the sterilized petri dish, then incubated.
A bacterial count was conducted after 24 hours, repeating the procedure for
the control group.
Figure 8 shows the theoretical bacterial growth and death cycle in a
constant nutrient substrate. To properly evaluate the toxic effect of polymer
for bacteria, an initial point was chosen on the growth and death curve (Fig-
ure 9a) to represent the initial raw sewage bacterial count which then became
the 100 percent count of the micro-organisms. At each of the selected time
periods, an increase or decrease in bacterial count was expressed as a per-
centage deviation from the initial count. A fixed nutrient condition was
chosen as a control parameter, since changes in nutrient concentration
(Figure 9b) affect the number of micro-organisms. With the initial nutrient
fixed for the incubation period, any growth or death of bacteria is reason-
ably dependent upon the sewage and polymer or nonsolvent added.
Figure 9c indicates the theoretical relationship of time with bacterial
count (i. e. , that expected from the growth testing since the added polymer
is a nutrient). The "sewage" curve indicates the growth of bacteria feeding
on a sewage as the available nutrient and their subsequent decline as the
nutrients are consumed. During the time period when the bacterial death
occurs on the sewage curve, the bacterial count is increased slightly on the
polymer and sewage curve and does not diminish as rapidly due to lack of
nutrients.
The bacterial counts were made by using a Quebec Colony Counter
on the petri dishes containing the sewage seeding or polymer and sewage
seeding. Standard methods were used in counting. The tabulations of all
data can be found in Table III.
Algae Test and Analysis Procedure. Water containing algae was
obtained from the sludge bed drainage pond at the Duck Creek Sewage Treat-
ment Plant (located near Garland, Texas). Three 200-milliliter, sterilized
Erlenmeyer flasks were filled to the 100-milliliter mark with this pond water.
These three flasks were used as a control group. Two additional 200 milli-
liter Erlenmeyer flasks were filled to the 100-milliliter mark with the pond
22
-------
CONSTANT
RATE OF
GROWTH
u>
CO
CO
<
O
%
6
oc.
O
O
-------
TIME
Fiaure 9a. Relatiorship of Initial Micro-Organ isms to Time, c-ased on
an Arbitrary Time or, the Theoretical Growth and Death Curve.
y.
g
il
CONCENTRATION of NUTRIENT
Figure 9b. Affect of Nutrient Concentration Upon Growth of Bacteria.
POLYMER and
SEWAGE
\
i
\
SEWAGE
TIME-
Figure 9c. Affect of Nutrient on Bacterial Count, With Respect to Time.
24
-------
TABLE III
BIOLOGICAL TOXIC ITY TEST
Polymer
Concentration
Additive (mg/1)
Average Bacterial Count by Percent
Number of Hours from Start
0 3 6 9 24 48 72
oTenBP'
C/ F
None
AP-30
WSR-701
WSR-301
FR-4
J-2FP
D-252
-H-AP-30
-H-WSR-701
-H-WSR-301
-H-FR-4
-H-J-2FP
-H-D-252
None
AP-30
WSR-701
WSR-301
FR-4
J-2FP
D-252
-H-AP-30
+KWSR-701
-H-WSR-301
-H-FR-4
-H-J-2FP
H+D-252
None
AP-30
WSR-701
WSR-301
FR-4
J-2FP
D-252
-H-AP-30
-H-WSR-701
•H-WSR-301
-H-FR-4
-H-J-2FP
-H-D-252
100
100
100
100
100
100
100
100
100
100
100
100
_ — fm
500
500
500
500
500
500
500
500
500
500
500
500
_._
500
500
500
500
500
500
500
500
500
500
500
500
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
204
190
179
202
178
167
162
214
199
220
137
165
148
120
154
136
148
152
158
153
178
165
161
141
139
203
89
89
87
98
82
75
80
77
86
74
89
69
74
163
142
142
170
155
170
135
168
130
158
158
117
116
157
184
139
145
134
105
140
84
233
166
144
122
175
63
62
21
67
59
70
61
63
68
46
54
50
41
201
137
136
122
125
140
130
140
167
153
210
141
155
166
166
134
128
114
124
121
117
142
156
120
116
164
59
66
55
59
62
68
65
54
53
44
60
56
68
165
99
123
115
137
112
140
147
160
168
179
103
97
40
158
94
78
108
164
107
104
86
81
65
122
116
63
121
91
66
60
81
73
87
114
81
94
67
106
88
147
95
117
116
98
104
151
130
152
125
80
90
18
60
25
22
103
53
58
148
112
85
131
54
175
33
66
81
72
72
70
71
83
87
82
68
56
68
124
98
112
75
94
81
90
141
100
107
117
87
90
18
46
14
12
76
52
27
120
77
90
59
55
92
69
73
66
72
62
67
72
59
56
77
62
80
52
20.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
29.5/85
2/35.6
2/35.6
2/35.6
2/35.6
2/35.6
2/35.6
2/35.6
2/35.6
2/35.6
2/35.6
2/35.6
2/35.6
2/35.6
agent, each by weight).
25
-------
water, and a polymer was added to achieve the desired concentration. The
flasks were then placed in a constant-temperature bath maintained between
23°C and 26°C (this temperature range approximated that of the pond where
the samples were obtained). A 450-foot-candle light source was placed
above the bath to maintain constant light intensity for photosynthesis. At
selected time intervals, 1-milliliter samples were withdrawn from the Erlen-
meyer flask and transferred to a microscopic slide for algae counting under
a microscope equipped with a Whipple eye piece. Five random locations
on the grid in the eye piece were counted and the results averaged.
The algae growth testing was conducted at two. polymer concen-
trations (100 and 500 milligrams per liter) which provided an adequate
range of conditions. The initial algae count of the pond water was con-
sidered to be 100 percent with subsequent algae counts, at specific time
intervals, reported as deviations from the initial count and expressed as
a percentage. An increase or decrease in algae count from the control group
would indicate the nutrient or the toxicity affect of polymers on algae (Ref-
erence 3). Data from the testing of algae can be found in Table IV. Tests
were also conducted on the nonsolvents to be used in producing slurries.
Fish Test and Analysis Procedure. The study of toxicity of polymers
on fish was conducted with a test matrix involving three control groups for
each polymer concentration. Tests were conducted at three polymer con-
centrations (50, 100 and 500 milligrams per liter), by using three samples
at each polymer concentration.
A plastic swimming pool, five feet in diameter, served as a con-
stant temperature bath, and temperature control was maintained by the
cooling coils of a refrigeration unit. The temperature range was 20°C to
22°C, which approximated that of local pond water from which the guppies
used were obtained. Each sample unit contained five guppies in 2. 25 liters
of the same pond water in which they were kept.
Toxicity effects of each polymer on the fish were evaluated by
counting the fish still living at selected time intervals in the control group
and in the test groups containing the polymers and the nonsolvents. The
results were then reported as a percentage of fish remaining based on initial
number of fish in the control group. Tabulated data can be found in Table V.
Bacteria Data Evaluation. In Figure 10, the combined data taken
from Table III for the investigating period, indicates that minimal bacterial
growth occurred in the sewage control at 48 hours. During this same test
period higher counts of bacteria were obtained in the polymer-sewage mix-
tures. The data indicates that the bacteria were using the polymer as a
food source. Lower polymer concentrations influenced growth to the extent
that the total quantity of food available was reduced. Temperature reduc-
tions simply lowered bacteriological activity, thereby reducing growth.
26
-------
TABLE IV
ALGAE TOXICITY TEST
Polymer
//-«_ ii \
Additive (mg/1)
None
AP-30
WSR-701
WSR-301
FR-4
J-2FP
D-252
AP-30
WSR-701
WSR-301
FR-4
J-2FP
S-252
Cellosolve
Cellosolve
Isopropanol
Isopropanol
— • —
100
100
100
100
100
100
500
500
500
500
500
500
100
500
100
500
Average Algae Count by Percent
0
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
Number of Hours from Start
6
212.7
207. 1
321.4
150. 0
135.7
185.7
207. 1
185.7
157. 1
285.7
221.4
164.3
244.4
122.2
111. 1
133.3
111. 1
9
160. 3
128.6
150. 0
121.4
78.6
92.8
114. 3
114.3
164. 3
135.7
71.4
128.6
211. 1
133.3
100.0
77.8
66.7
24
136. 5
64.3
92.8
71.4
64. 3
100. 0
78.6
100. 0
221.4
285.7
221.4
150. 0
133. 3
100. 0
88.9
188.9
77.8
48
85.7
78.6
42.8
57. 1
57. 1
142. 8
42.8
64.3
200.0
1 07 . 1
71.4
57. 1
66.7
155.6
155.6
44.4
111. 1
72
86.8
71.4
114.3
50.0
57.1
114.3
35.7
71.4
164.3
64.3
28.6
57.1
77.8
100.0
100.0
33.3
44.4
•H- Concentration
27
-------
TABLE V
FISH TOXICITY TEST
Additive
None
AP-30
WSR-701
WSR-301
FR-4
J-2FP
D-252
None
AP-30
WSR-701
WSR-301
FR-4
J-2FP
D-252
None
AP-30
WSR-701
WSR-301
FR-4
J-2FP
D-252
None
Cellosolve
Cellosolve
Cellosolve
Isopropanol
Isopropanol
Isopropanol
Polymer
Conc.-tt
(mg/1)
Averaae Fish Count by
0
100
50 100
50 100
50 100
50 100
50 100
50 100
--- 100
100 100
100 100
100 100
100 100
100 100
100 100
--- 100
500 100
500 100
500 100
500 100
500 100
500 100
--- 100
50 100
100 100
500 100
50 100
100 100
500 100
6
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
Time
12
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
87
100
100
100
100
100
93
100
100
100
100
100
100
Percentaae Remainina
(Number of Hours from Start)
24
100
93
100
100
93
100
100
100
100
100
100
100
100
100
100
67
93
100
87
100
100
87
100
100
100
100
100
100
30
100
93
100
100
87
100
100
100
100
100
100
100
100
100
100
67
93
100
87
100
93
87
100
93
100
100
100
87
36
100
93
100
100
87
100
100
100
100
100
100
100
100
100
100
67
93
100
87
100
93
87
100
93
100
100
100
87
48
96
93
93
100
87
100
100
100
100
100
100
100
100
100
100
60
87
100
87
100
93
87
100
93
100
100
100
87
54
96
87
93
100
87
100
100
100
100
100
100
100
100
100
100
60
87
100
87
100
80
87
100
93
100
100
100
80
60
96
87
93
93
87
100
100
100
100
100
100
100
100
100
100
60
87
100
87
100
80
87
100
93
100
100
100
80
72
96
87
93
93
87
93
100
93
100
100
100
100
100
100
93
60
87
100
87
100
80
87
100
93
93
100
100
80
-H- Concentration
28
-------
o
I i
ID
M,
to
i
w
to
hi
c
0)
;. ,
fil
I/,
(0
CO
6
w
'Sewage only
Upper limit
Average
Lower limit
for all data at each time
for sewage fc polymer
IU
8
O
L*
O
i
•4H
O
>.
4—*
-•H
+J
c
fO
.5
\,^ • — — __
- 80
- 60
- 40
- 20
4 8 \2 16 20 2'. 28 32 36 40 44 4-8 52 56 60 64 68 72
Hours After Start of Test
Figure 10. Growth of Micro-Organisms in Sewage and Polymer-Sewage Material Including
Nonsolvents Used.
-------
Comparative tests were made between polymers in the powdered
form and in the slurry form. The nonsolvents, cellosolve and isopropyl
alcohol, used in the slurried polymers proved to be generally nontoxic to
bacteria in the magnitudes used. The slurry consisted of polymer (40 per-
cent by weight), nonsolvent (59. 5 percent by weight) and gelling agent
(0. 5 percent by weight).
The efficiency of sewage degradation by micro-organisms remains
essentially unaltered when polymers are present. The tests proved that the
polymers evaluated are nontoxic to the bacteria under the conditions of the
tests. Thus, polymer injection into a sewer system should not be detrimen-
tal to the micro-biological treatment process in a sewer treatment plant.
Algae Data Evaluation. The curves in Figure 11 are taken from the
combined data in Table IV. The trend is similar to that shown in Figure 10.
There is only a slight deviation of the average combined data curve from the
sewage curve; therefore, the polymers tested have no toxic or nutrient affect
on algae under the concentrations and conditions tested.
Since the polymers tested are nontoxic and do not serve as a nutrient
to algae, polymer injection into a surcharged sewer should have no undesir-
able affect upon algae in a lagoon, lake or stream after discharge as the ef-
fluent from a sewage treatment plant. Also, if polymer injections are used
in storm sewers, the discharge should have no appreciable affect on the
algae of the receiving waters.
Fish Data Evaluation. The data in Table V indicates a non-toxic
affect of the polymers tested upon guppies used as subjects in the fish
evaluation. There was a slight lowering in the percentage of fish remaining
at a polymer concentration of 500 milligrams per liter; however, these values
are within the realm of probability of natural deaths for the fish although it
appeared that some of the polymers had a tendency to clog the gills.
Data for nonsolvents (cellosolve and isopropyl alcohol) used in the
test program were included because polymer injection will usually be con-
ducted by using slurries. The largest percentage, by weight, of a slurry
consists of a nonsolvent, and the possibility exists that the nonsolvent
might have deleterious affects upon marine life; however, data acquired
during the environmental study show no appreciable toxic affects upon fish
as the result of nonsolvents applicable to this program under the conditions
of the tests. Therefore, the use of polymers as friction reducers in sanitary
sewers will not contribute indirectly to lake or stream pollution by having a
toxic affect upon fish life.
Polymer-Nonsolvent Slurry System Study
Slurry Formation. Water-soluble polymers dissolve readily in water;
however, the solvation process involves thoroughly dispersing the individ-
ual resin particles during the first two or three minutes. As the polymer
surfaces begin absorbing the solvent, they become very cohesive. Upon
contact of the particles during this wet-out period, an agglomerate is formed
30
-------
oewage only
Upper limit
Average
Lower limit
all data at each time
for sewage and polymers
Hours After Start of Test
Figure 11. Growth of Algae in Sewage, and in Polymer-Sewage Media.
-------
and prolonged agitation is required to dissolve the agglomerate or gell-like
mass. By keeping the particles separated, the particle surface quickly dis-
solves, producing a protective envelope or film of viscous solution around
the particle. The particle solvation proceeds with the solution viscosity
increasing rapidly.
Since dispersion is necessary to enable the resin particles to be
quickly and completely dissolved, a method is required to maintain polymer
dispersion for the solvation process. Predispersion, of polymers in a non-
solvent that has been gelled, meets this criteria. Cellosolve (ethylene
glycol monoethyl ether) gelled with a cellulose ether is an effective system
for slurry formation of AP-30, FR-4 and J-2FP.
Anhydrous isopropanol gelled with a cellulose ether has shown to be
an effective system for slurry formation of polyethylene oxides (WSR-301
and Polyox Coagulant-701.
The dispersion of polymers in slurry form can be prepared readily,
stored for long periods and used as needed. These slurries, when added
to water, form aqueous systems quickly and with minimum agitation, and
are useful for large-scale operations where speed is necessary in getting
the polymers dissolved quickly.
One polymer, D-252, would not lend itself to predispersion in a
gelled nonsolvent. The incompatibility was due to a double convex particle
shape which prevented a 40-percent polymer loading in the gelled nonsolvent
(cellosolve). Settling occurred in this suspension and the slurry was not
easily pumped.
Slurry Degradation. Since polymers are known to degrade in aqueous
systems, there existed a possibility that degradation might occur in the
slurry system.
Degradation implies polymer chain scission and is reflected by a
reduction in molecular weight of the polymers. Polymer chain cleavage is
effected by mechanical agitation, by ultraviolet light, by bacteriological
action, and by chemical oxidation due to dissolved air.
Reduction of molecular weight due to polymer chain scission is
evaluated by measuring a reduction in the aqueous solution's viscosity.
In this study a weighed quantity of the desired polymer in slurry form
was added to a weighed quantity of tap water to give a concentration of poly-
mer at 500 ppm. This concentration of polymer was chosen, since the time
required to measure the relative viscosity was less than three minutes per
sample, which minimized experimental error due to degradation in the aque-
ous system. At the end of the first 24 hours of combined materials, the
polyacrylamides degraded by 0. 52 percent and polyethylene oxides degraded
by 4. 1 percent. Thus, a measure of the relative viscosity of a freshly made
aqueous polymer solution from a slurry would show if cleavage of polymer
chain or degradation occurred to the polymer while stored in slurry form.
32
-------
In the evaluation procedure, a 12-milliliter sample of the polymer
test solution was introduced into a Ubbelohde Viscometer and the time of
passage for this quantity of aqueous polymer solution obtained. The ex-
periment was conducted in a constant temperature bath of 75°F, with the
test solution being equilibrated prior to the time measurement was taken
in the Ubbelohde Viscometer. The relative viscosity measurements ob-
tained were defined as the ratio of time for the aqueous polymer solution
(12 milliliter) to flow to the time for tap water (12 milliliter) to flow in the
Ubbelohde Viscometer. The experimental error expected for relative vis-
cosity measurements in the Ubbelohde Viscometer was - 10 percent. From
Figure 12, the plot of relative viscosity versus time implies no appreciable
degradation occurring to polymers in a slurry form. The percents of error
based on the average of relative viscosity measurements (shown in Table
VI), taken over a 50-day period for AP-30, FR-4, Polyox Coagulant-701
and WSR-301, were recorded as 6.3 percent, 2.9 percent, 1.4 percent,
7. 2 percent and 2. 9 percent, respectively. This range is well within the
expected experimental error of relative viscosity measurement.
TABLE VI
PERCENT ERROR IN VISCOSITY DETERMINATIONS
Relative
Polymer Viscosity
AP-30
FR-4
Polyox
Coagulant-
701
WSR-301
3.502
3.708
2. 118
2.770
3.013
2.908
2.290
2.082
1.852
1.851
1.805
1.710
Average Average
Relative Standard
Viscosity Deviation Deviation
3.443 -0.
-0.
+0.
2.897 +0.
-0.
-0.
2.0746 -0.
-0.
+0.
1.7886 -0.
-0.
+0.
0594 .216
2654
3246
1270 .0847
1160
0110
2154 .1485
0074
2226
0624 .0525
0164
0786
Precision
6.3
2.9
7.2
2.9
Effect of Polymers on Sewage
Purpose of Tests. Evaluation of polymer affects on sewage was
enabled by measurements of those parameters that produced the most sig-
nificant information, e.g., dissolved oxygen, biochemical oxygen demand,
33
-------
-------
change in settleable solids, percent moisture change in sludge drying beds,
total solids in sludge drying beds, and volatile solids in sludge drying beds.
Sedimentation Test and Analysis Procedure. Information, obtained
from suppliers of the six selected polymers indicated that each polymer had
the ability to settle inorganic and organic material--they all exhibited a
varying ionic character that was pH dependent, which allowed them to be
generally classified as polyelectrolytes. (Note: The exact mechanism by
which the polymers agglomerate the suspended material is not known but,
once formed, it should exhibit a strong bond and be quickly and irreversibly
formed).
To determine the increase in sedimentation by polymer addition, a
1-litter graduated cylinder was filled to the mark with raw sewage (from the
Rowlett Creek sewage treatment plant) for use as a control. At the same
time, three 1-liter graduated cylinders were filled with the raw sewage
and enough polymer was added (by weight) to obtain polymer concentrations
of 100, 200 and 500 milligrams per liter. These samples were used to det-
ermine the magnitude of settling of the polymers, so that sewage settling
could be determined.
A standard two-hour settling time was used for each graduated
cylinder containing sewage, polymer/sewage and polymer/distilled water.
Then, all but 100 milliliters were decanted from each cylinder, leaving
essentially the settleable solids, and some water to be evaporated on a
water bath. After evaporation to dryness, the solids were weighed and the
milligrams per liter of settleable solids determined.
For analysis, the amount of polymer that settled in distilled water
was subtracted from the amount of sewage and polymer that settled. This
difference left the net quantity of sewage settled by the polymer. This
quantity was then divided by the quantity of sewage that settled in the
control, with the results expressed as a percentage. Values greater than
100 percent indicated an increase in sedimentation due to the addition of
polymers.
Biochemical Oxygen Demand (BOD) Test and Analysis Procedure.
Standard Methods (Reference 2) were used to determine biochemical oxygen
demand (BOD) and dissolved oxygen (DO).
It has been shown that the polymers, being carbonaceous organic
materials, are usable as a source of food by micro-organisms and, there-
fore, exerted an oxygen demand. Adequate DO is required for aerobic deg-
radation of sewage, whether it takes place in sewer lines, in sewage treat-
ment plants, or in effluent receiving waters.
Since polymers are degraded by both chemical oxidation and bacte-
rological action, measurement of the DO will allow establishment of the
oxygen requirements for polymers. By using 500 milligrams per liter con-
centrations, which are above the upper limit to be used, an extreme limit
of oxygen use by the polymers was provided.
35
-------
The standard BOD provides data for measurement of the stabilization
of the oxidizable organic polymer systems.
Sludge Test and Analysis Procedure. A principal by product of sewage
treatment is sludge. One method of disposal is to pump the digested sludge
onto drying beds where it dries by drainage and/or evaporation. Since the
polymer agglomerates the solid material in sewage, the resulting treated
sludge may contain some of the polymer following an injection into a sewer
line or prior to a plant function. By measuring the moisture content, the total
solids, and the volatile solids, effects of the polymer on the sludge drying
beds may be determined. Figure 13 shows the schematic arrangement and
sizes of the test bed system used in evaluation of polymer affects on sludge
drying.
The drying bed, constructed of 2-inch by 12-inch lumber, was placed
on an existing underdrained sludge bed to a depth of 2 inches. A 55-gallon
barrel, fitted with a quick-closing/opening valve, was used as a mixing
chamber. Enough polymer to prepare a 50- and a 200-milligram-per-liter
concentration was added to 40 gallons of sludge, mixed and then drained
onto one bed of the form. Four test beds of raw sludge were used as con-
trols plus one bed for each polymer at each of the concentrations. In addi-
tion, a full-size sludge bed was filled with the same sludge at the same
time the test beds were filled. Over a 28-day test period, 12 samples were
taken from each of the test beds at specific time intervals. The moisture
content was determined (by weight difference, before and after it was dried)
and expressed as percent moisture. Other samples of 100-milliliter size
were evaporated over a water bath according to standard methods (Reference
2) for total solids determination. The total solids samples were also used
in determining the total volatile solids.
Sedimentation Data Evaluation. In Figure 14, the combined sedimen-
tation data from Table VII for all polymers at varying concentrations indicate
sedimentation capability; however, it should be noted that the percentage
increase in sedimentation is dependent upon increases in polymer concen-
tration. Figure 15 shows the order of sedimentation ability for each polymer
at different concentrations.
Some loss of polymer may occur following injection into a sewer due
to sedimentation; however, since injection will only be done when the sewer
is surcharged, turbulence will keep the solids in suspension, and most of
the polymer injected will be available for energy reduction and for the ac-
companying possible increase in settling of solids in the treatment plant.
BOD Data Evaluation. A maximum polymer concentration of 500 mil-
ligrams per liter was chosen for the BOD determination because magnitude
was not of any great importance with respect to the sewage BOD (smaller
concentrations of polymers would be even of less importance in the sewer
systems).
Based on the standard BOD test, Table VTII indicates that the bio-
chemical oxygen demand for all polymers is 1. 56 milligrams per liter for a
polymer concentration of 500 milligrams per liter. Essentially, this value
36
-------
r
"o
I
OJ
— iz-o •—
WSR-301
2OO mg/l
FR-4
200mg/l
WSR-701
50mg/l
SEWAGE
SLUDGE
ONLY N0.4
SEWAGE
SLUDGE
ONLY No. 1
WSR-701
200mg/l
D-252
50mg/l
FR-4
50 mg/l
i
D-252
200 mg/ 1
AP-30
50mg/l
SEWAGE
SLUDGE
ONLY NO. 3
AP-30
200 mg/l
J-2FP
50 mg/l
SEWAGE
SLUDGE
ONLY NO. 2
J-2FP
200 mg/l
WSR-701
50mg/|
Figure 13. Sludge Drying Test Beds.
-------
OJ
00
JX
"c
o
0>
en
(0
£
(1)
o
T3
0}
w
(0
CO
O
•«-4
•M
(0
s
Q)
-c-4
T3
(D
CO
-M
C
-------
TABLE VII
SEDIMENTATION CAPABILITY OF POLYMERS
Additive
AP-30
AP-30
AP-30
AP-30
FR-4
FR-4
FR-4
FR-4
D-252
D-252
D-252
D-252
J-2FP
J-2FP
J-2FP
J-2FP
WSR-301
WSR-301
WSR-301
WSR-301
WSR-701
WSR-701
WSR-701
WSR-701
Polymer
Cone. +
(mg/1)
0
100
200
500
0
100
200
500
0
100
200
500
0
100
200
500
0
100
200
500
0
100
200
500
Setteable Solids (mg/1
Sewage
&
Polymer
119
172
216
269
551
730
642
886
89
144
195
367
122
163
204
399
86
162
236
448
276
_ —
295
368
Polymer
0
9
20
34
0
68
145
265
0
50
91
214
0
46
45
69
0
49
126
313
0
41
43
Net
Sewage
119
163
196
235
551
662
497
621
89
94
104
153
122
117
159
330
86
113
110
135
276
254
325
)
Percent
Net Sewage
Only Results
100
137
165
197
100
120
90
113
100
106
117
172
100
96
130
270
100
131
128
157
100
92
118
-H- Concentration
39
-------
0)
: '
. '
10
: -
,,,
(31
m
&
(U
Q]
: :
•.
o
•>-
03
01
to
I
'
. I
I •
10
' '
• :
0)
CO
1 ^
a
•.
QJ
P
50
100
zoo
I
500
O AP-30
A FR-4
O.D-Z52
D J-ZFP
V WSR-301
X WSR-701
400
•150
Polymer Concentration, ppm
Figure 15. Sedimentation Capabilities of Polymer on Settleable Solids.
-------
indicates a very slight increase in oxygen demand of polymer sewage mix-
tures when compared with the raw sewage used in these tests which is in
the general range of 200 milligrams per liter.
TABLE VIII
BIOCHEMICAL OXYGEN DEMAND (BOD) OF POLYMERS
Polymer
Concentration
Additive (mg/1)
AP-30
FR-4
D252
J-2FP
WSR-301
Polyox -
Coagulant- 7 01
500
500
500
500
500
500
DO at
Start
(mg/1)
7.70
7.80
8.20
8.20
7.60
5.90
DO at
5 days
(mg/1)
6.25
6.60
6.35
5.70
5.75
5.40
BOD at
5 days
(mg/1)
1.45
1.20
1.85
2.50
1.85
0.50
IZK
20/68
20/68
20/68
20/68
20/68
20/68
Sludge Data Evaluation. The sludge data in Tables DC and X were
treated by the method of least squares and the results are plotted in Figures
16, 17 and 18. Figure 16 shows that, at the beginning of the test period,
the percent moisture is lower in sludge alone than it is in sludge and poly-
mer mixtures; however, as time progresses, the sludge-polymer mixtures
have a much lower percent moisture value. From this data it is reasonable
to assume that the polymers are beneficial in decreasing the water-retention
capability of sludge; therefore, over a given time, yielding a dryer sludge
cake for earlier disposal.
In studying Figures 17 and 18 for total solids and volatile solids,
it is apparent that the polymers increase the total solids and volatile solids
per unit of volume over the test period. Since the polymers help in moisture
reduction, it is expected that with time, values for total solids and volatile
solids would increase in the sludge drying beds.
41
-------
TABLE DC
AFFECT OF POLYMERS ON SLUDGE DRYING BEDS
Polymer
or
Sample
Sludge Bed
Sludge Only
AP-30
AP-30
FR-4
FR-4
J-2FP
J-2FP
D-252
D-252
WSR-301
WSR-301
WSR-701
WSR-701
Polymer
Cone
(mg/1)
Percent Moisture
Days from Start
0
none 92. 61
none 93. 16
50 93.56
200 93.55
50
200
50
200
50
200
50
200
50
200
93.49
93. 76
93.52
93.49
93.02
93.81
93.59
96.67
93.54
92.74
1
90.22
90.58
91. 82
90.90
91.07
91.91
91. 16
91.64
90. 67
92.23
91.63
91.74
91.48
91.70
3
87.85
87. 68
87.26
87.45
84.26
87. 56
88. 68
87.94
88.50
88.46
87.06
88.77
88. 74
89. 09
7
81. 38
76. 10
79. 2.3
71. 03
80. 24
76. 98
80. 08
71.98
79.31
82. 39
81.40
81.38
74.20
81.49
14+
81. 32
77.21
76. 06
74. 38
71. 12
72.80
71. 42
71. 30
72.85
74. 06
76.59
75.67
71.42
75.45
28
72. 48
60. 65
64. 04
65. 44
65.42
58. 97
66. 24
32. 33
48. 48
30. 76
51.74
40. 78
30.20
61.69
NOTE: "Sludge bed" is an average of two readings taken from a large
sludge bed.
"Sludge only" is an average of four readings taken from four
tests beds.
-tfRained during morning while samples were taken.
42
-------
TABLE X
AFFECT OF POLYMER ON SLUDGE DRYING BEDS.
Polymer
or
Sample
Polymer
Cone .
(ma/1)
Total Solids (tng/1)
Days from Start
0
1
3 7
14*
28
Volatile Solids (mg/l)
Days from Start
0
1
3 7
14*
28
Sludge Bed none 73,890 97,802 121,575 186,240 186,891 275,237 40,985 53,925 66,336 98,694 100,384 143,912
Sludge Only none 68,357 94,219 123,192 239,024 254,421 393,423 37,395 49,293 67,765 128,549 135,700 170,918
AP-30 50 64,407 81,821 127,404 207,683 239,393 359,600 36,126 45,959 72,462 115,539 130,987 177,827
AP-30 200 64,550 90,963 125,468 289,653 256,245 345,625 36,288 50,360 68,652 160,272 145,744 191,269
FR-4 50 65,085 89,310 157,413 197,563 288,833 345,847 36,231 48,639 86,860 110,042 141,125 183,692
FR-4 200 62,366 80,888 124,419 230,243 272,033 410,309 36,132 45,324 71,406 131,037 155,260 223,349
J-2FP 50 64,775 88,376 112,981 199,154 285,808 337,634 36,904 43,787 63,218 112,685 157,824 182,389
J-2FP 200 65,088 83,558 120,636 280,235 287,042 676,737 36,101 46,451 63,768 155,429 158,027 366,549
D-252 50 69,769 93,298 115,005 206,862 271,467 515,176 39,178 51,715 65,131 118,007 145,766 287,044
D-252 200 61,948 77,681 115,441 176,125 259,409 692,403 35,466 44,649 66,222 98,898 140,732 386,643
WSR-301 50 64,150 83,750 129,367 185,955 234,145 482,570 35,548 46,338 72,160 100,134 130,648 253,583
WSR-301 200 33,328 82,545 112,316 186,219 243,339 592,230 7,166 47,344 64,754 107,985 150,182 327,966
WSR-701 50 64,567 85,204 112,641 258,005 285,809 697,951 35,517 47,081 62,213 137,807 157,722 379,466
WSR-701 200 72,586 83,001 109,123 185,052 245,490 383,103 41,730 46,802 61,816 105,686 133,404 201,867
NOTE: "Sludge bed" is an average of two readings taken from a large sludge bed.
"Sludge only" is an average of four readings taken from four test beds.
*Rained during morning while samples were taken.
-------
O - Combined Sludge Data
D - Combined Polymer Data at 50 mg/1
A - Combined Polymer Data at 200 mg/1
8 10 12 14 16 18 20 22 24 26
Time in Days
Figure 16. Affects of Polymers (at Different Concentrations) on
Moisture Content of Sludge.
44
-------
-
"-
c
X
I
-
TJ
-
• —
GO
C
-—.
CO
T3
-
— '
o
E-i
550
30
Z
O - Combined Sludge Data
D — Combined Polymer Data at 50 mg/1
A - Combined Polymer Data ZOO mg/1
J L
10 1Z 14 16 18 ;0
J 1 1 ' ' '
ZZ Z4 26
J 1 l_
Time in Days
Figure 17. Affect of Polymers (at Different Concentrations) on Total
Solids Content of Sludge.
45
-------
Combined Sludge Data
Combined Polymer Data at 50 mg/1
Comoiaed Polymer Data at 200 mg/1
Time in Days
Figure 18. Affect of Polymers (at Different Concentrations) on
Volatile Solids Content in Sludge.
46
-------
SECTION IV
FLOW-TEST EVALUATION OF POLYMERS
Flow testing for additional evaluation of the six polymers previously
selected was conducted in a six-inch diameter test sewer designed initially
to provide a means of testing the polymers, both as surcharged closed-
conduit flow and open-channel flow.
In addition, the same facility was used with a four-inch diameter
line for the establishment of injection locations in a line to optimize
the operation with respect to the hydraulic cause of the surcharging of a
line.
Description of Flow-Test Facilities
Six-Inch Diameter Sewer. A 100-foot-long section of six-inch
asbestos-cement and transparent plastic sewer pipe was constructed to
evaluate the effects of different energy-re due ing polymers on sewage under
different flow conditions. The facility (see Figure 19 for a schematic
drawing) was constructed so that the following parameters could be varied
to provide the variations in flow characteristics needed in the program.
TABLE XI
TEST FLOW PARAMETERS
Parameter Range
Temperature, °F 38 ~ 90
Slope, percent 0.3-2
Flow Rate, gpm 0 - 750
Polymer concentration, mg/1 ° - 1.500
Sewage concentration, ml/1 As required
The temperature of the water or sewage used in the test program
was controlled by a combination heating and cooling recirculation system.
The heating system was a 800,000 btu per hour output boiler designed to
heat 22, 500 gallons of sewage from 65°F to 90UF, in 8 hours. The refrig-
eration system consisted of four 15-ton cooling units and one 25-ton
cooling unit operated in series with a total system output of 85 tons
(1,020,000 btu/hr.) which was sufficient to cool 22,500 gallons of sewage
from 70°F to 38°F in 12 hours. The lowest testing temperature was
established as the temperature at which icing would not occur in the
evaporators, and thereby prevent possible damage to the units and a delay
in the test program.
The slope of the test pipe could be adjusted to obtain a maximum
of a two-percent flow-line slope. To accomplish this, the entrance of the
47
-------
sewer line was fixed and the line was mounted on an I-beam which was
supported every 20 feet by a vertically adjustable base. The span and
shape properties of the I-beam were such that the flow line of the pipe
would not deflect more than 0. 08 inch under the maximum live and dead
load anticipated. The slope of the line during testing was established
by using an engineer's level.
The sewage flow was accomplished by the use of a Marlow, Model
4C7 centrifugal pump driven by a gasoline engine which was fitted with a
gate valve for flow rate control. Flow rates up to 750 gallons per minute
could be achieved by varying the engine revolutions per minute and/or
the gate valve opening.
The polymer concentration in the sewage was achieved by pumping
a concentrated polymer slurry from a 1,000-gallon storage tank into the
sewage with a variable volume, positive displacement pump capable of
pumping at rates from zero to 175 gallons per minute. The flow rate of
the concentrated polymer solution was determined from a calibration curve
of pump output versus the pump vernier scale reading. The injection of
the polymer occurred ahead of the test sewer section at variable rates
capable of providing concentrations of 0 to 1, 500 milligrams per liter in
the sewage.
Sewage concentration was measured as a function of settleable
solids in terms of milliliters per liter. To facilitate the addition of
concentrated sludge (obtained from a local treatment plant) to water in
the 22, 500-gallon reservoir, a diaphragm pump was used to transfer the
sludge from the transport truck. During this manufacturing process, the
4-inch gasoline driven centrifugal pump was used to provide homogeneity
by using a recirculation loop. Sampling ports were provided to various
locations along the sewage reservoir to facilite sample withdrawal for
chemical analysis.
A 30-foot section of the 100-foot conduit was chosen for measure-
ment. This measurement section was located 100 pipe diameters (50 feet)
downstream of the line entrance. The 100-pipe-diameter approach length
was provided to insure that all entrance affects had been suppressed and
that full turbulent flow had been established. The length of the test
section was determined to allow the flow to be analyzed over three pipe
sections. This minimized the affect of the pipe joints and gave pressure
drops of sufficient size to be read easily. Two sections upstream from the
test zone, a transparent section was installed for visual observation of
the additive mixing with the sewage.
The six-inch test facility was instrumented to provide the data
and ranges indicated in Table XII.
48
-------
PAGE NOT
AVAILABLE
DIGITALLY
-------
TABLE XII
TEST PARAMETERS AND RANGES
Data Range
Temperature, °F 0 - 200
Flow Rate, gpm 0 - 1,000
Static Pressure at Sewer Line Entrance,
inches H2O 0-60
Static Pressure at Start of 30-Foot Test
Section, inches H2O 0-205
Static Pressure Drop Across 30-Foot Test
Section, inches H2O 0-20
Three temperature indicators were used. One indicator was placed
in the storage tank, one placed just prior to the 30-foot test section and
one placed just after the 30-foot test section. The sensors used were
Weston bimetal thermometers with an accuracy of +_ 1/2 percent of the
reading with the bulb directly immersed in the sewage flow.
A flowmeter was designed in the feed line following the primary
pump. The flowmeter consisted of a six-inch Foxboro meter and transmitter
(Type 1806-KAOS-RA) in conjunction with a Dynalog Electronic Recorder
(Model No. 9650C) providing an overall flow measuring accuracy of 4^ 1
percent. As a system check, the effluent of the six-inch line emptied into
a catch basin which contained a standard 90-degree V-notched weir.
The static pressure-head at the sewer line entrance was read through
the use of a vertical sight glass marked every 0.0625 inches.
A pressure transducer was installed at the start of the 30-foot sec-
tion (50 feet from sewer line entrance) to measure the static pressure at
this point. The pressure monitoring system consisted of a Foxboro Model
613 DM differential pressure transmitter in conjunction with a Sargent Model
SR recorder. This system provided readings +_ 1 percent of full-scale trans-
ducer capability. The low side of the transducer was vented to atmospheric
conditions.
Another pressure monitoring system similar to the above system was
provided to measure the static pressure drop across the 30-foot test section.
Four-Inch Injection Point Effect Test Facility. A four-inch flow
system was built from the six-inch facility reservoir, pump, flowmeter and
the instrumentation. It was used to determine the most desirable distance
upstream from a flow constriction at which polymers should be injected.
51
-------
Two four-inch lines were manifolded from the flowmeter and provid-
ed with manual gate valves to regulate the flow in each line (Figure ZO).
One of the lines was fitted with a Hersey rotating disc flowmeter so that
the flow in each line could be determined by a mass flow balance. The
other line contained four injection points placed at distances of 7, 12, 17
and 22 feet upstream from the constriction formed by the junction of two
4-inch lines discharging into one 4-inch conduit and certain fittings. The
same polymer injection technique was used as in the six-inch system. The
system was designed to accommodate all the restrictions tested, including
the circular cross-section long-radius ell, short-radius ell, tee and the
wye, and the square cross-section wye. For testing the ells, provisions
were made for cutting off the non-injection leg of the system. A transparent
section was installed downstream of the seven-foot injection port so that
visual inspection of polymer/sewage could be made. Pressure taps were
installed five feet upstream and five feet downstream of the restriction so
both static pressures and differential static pressures across the constric-
tion could be monitored.
Flow Test Procedure
Sewage Preparation. The sewage produced by mixing water and sludge
was developed to the required concentration by diluting raw sludge with wa-
ter in the 22, 500-gallon reservoir. The sewage reservoir was filled with
water to within about 95-percent capacity and the raw sludge was then add-
ed to the water which was kept under constant agitation to insure reason-
able homogeneity of the sewage in the storage reservoir. Samples were
taken from the reservoir periodically until the desired sewage concentration,
based on milliliter per liter of settleable solids, was achieved.
Polymer Preparation. To facilitate handling of the polymers during
testing, a slurry was first prepared in the laboratory and then used to make
concentrated water/polymer solutions of 5,000 milligrams per liter in the
1,000-gallon additive storage tank. These solutions were agitated gently
for approximately four hours, then samples were taken to the laboratory for
viscosity tests to insure that complete hydration had occurred. An inert
tracer dye was added to the solution so the additive could be observed dur-
ing the testing procedure to determine the degree of mixing of additive with
sewage. A detailed discussion of the technique used in mixing the polymer
slurry is given in Appendix D.
Thermal Conditioning. Once the desired sewage concentration had
been achieved, the sewage was adjusted to the proper temperature for test-
ing. The cold runs at 38°F were achieved after an overnight chill of the
sewage occurred by circulating the water/sewage mixture through the chiller
unit of the refrigeration equipment. The second set of data was made at the
ambient water temperature (approximately 70°F). Following this test, the
high temperature test at 90°F was performed by heating the sewage in the
same manner as the temperature reduction process with the exception that
the sewage was circulated through the boiler. This sequence of testing
(chill-down, ambient, heat-up) proved to be the most desirable since it
52
-------
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Four- Inch Flow System Schematic Diagram
-------
allowed for maximum utilization of test time (that is, it allowed night chill-
down and daytime heat-up which minimized the energy requirements for the
environmental testing).
Typical Flow Testing Procedure. Throughout the flow test program,
all instrumentation was periodically checked for calibration. The pressure
transducers were checked with a standard water manometer, the magnetic
flowmeterwas checked with a positive displacement flowmeter placed in
series on the line; the additive pump was checked in the same manner as
the magnetic flowmeter; and the thermal sensors were checked in a constant
temperature bath. Also, the slope of the sewer flow line was determined
before each run. The initial polymer concentration was arbitrarily selected
but subsequent concentrations were based on the calculations performed
during the testing. The polymers and concentrations tested are shown in
Table XIII below.
TABLE XIII
FLOW TEST POLYMER CONCENTRATIONS
Polymer Polymer Concentration (mg/1)
AP-30 100, Z50 and 500
FR-4 100, 250 and 500
D-252 100, 250 and 500
J-2FP 500 and 1,000
WSR-301 50, 100 and 200
Polyox Coagulant-701 50, 100 and 200
The six-inch sewer system's performance was determined with a
slope of 0.003 for three different head conditions for each polymer at each
concentration. The resulting sewage flow rates tested were 350, 450 and
550 gallons per minute. Additional testing was done at grades of 0. 3 and
1.0 percent.
The volume of the 22, 500-gallon reservoir was sufficient to provide
flow for twelve different data collection operations. Each set of data was
taken at a constant sewage concentration and sewage temperature. Three
sewage flow rates and three polymer concentrations at each flow rate were
tested.
Once the polymer solution and sewage were ready to be tested, flow
of sewage was started by the Marlow pump and the instrumentation was
zeroed. The system flow rate was then brought up to the desired value and
the vernier on the polymer injection pump was set at the proper value but
not actuated. The sewage flow system was then allowed to reach a steady-
state condition, sewage samples were taken for analysis and the following
data recorded:
54
-------
Date
Ambient temperature.
Sewage reservoir temperature.
Sewage temperature at the entrance of the test section.
Sewage temperature at the exit of the test section.
Sewage flow rate.
Static pressure at sewer line entrance.
Static pressure at the entrance of the test section.
Static pressure drop across test section.
Weir box reading.
The polymer injection pump was then started at the first concen-
tration setting, and the test section flow again was allowed to reach
steady state conditions. Again, the required data was recorded and the
procedure repeated (for the different polymer concentrations and sewage
flow rates) until the data matrix of 12 sets was completed.
Flow Restriction Test Procedure. Of the six polymers tested in the
six-inch test facility, four were selected for evaluation in the four-inch
test facility, to establish the most effective injection point distance up-
stream for typical flow restriction characteristics. The four polymers and
the concentrations tested are given in Table XIV.
TABLE XIV
RESTRICTION TEST POLYMERS
Polymer Polymer Concentration (mg/1)
AP-30 250 and 500
FR-4 250 and 500
WSR-301 100 and 200
Polyox Coagulant-701 100 and 200
During these restriction tests, water was used rather then sewage
because the data indicated minimum differences between water and sewage.
Preparation of the concentrated polymer solutions was identical to that
previously described.
All instrumentation was zeroed prior to each test run to prevent
recording errors and to insure that all instrumentation was functioning.
The test procedure for the four-inch system depended on the system con-
figuration being tested, and whether the flow constriction resulted from
deformational losses or was caused by the junction of two flows, as in
the tee and wye sections.
The procedure used for the long- and short-radius elbows was as
follows. The Marlow primary pump was started and the flow rate adjusted
to the flow rate to be used and, after steady-state flow conditions were
obtained, the following data recorded:
55
-------
Water temperature in the line.
Water flow rate.
Static pressure at entrance to the blockage area.
Static pressure drop across the blockage area.
Date.
Ambient temperature.
The polymer pump vernier was set to the proper injection rate and
the pump started. Injection was made at the nearest injection point (No.
1) first and the system allowed to reach steady-state prior to data record-
ing. This first injection point was then closed, and the second injection
point was opened, and the procedure was repeated for each of the other
two injection points.
The procedure used for the tee and the two wyes was as follows.
The Marlow primary pump was again started with the valves in the two
upstream lines in the full open position. Once the flow system reached
steady-state, the following data was recorded:
Water temperature in the line.
System total flow rate.
Water flow rate in the non-injection line.
Static pressure at entrance to turned flow portion
of the blockage area.
Static pressure drop across the straight flow
portion of the blockage area.
Static pressure drop across the turned flow
portion of the blockage area.
Ambient temperature.
The same injection procedure and data acquisition was then follow-
ed as described for the elbows. The injection system was then taken off
line and the flow was redistributed through the two legs of the primary
flow system in the lines. The above procedure was repeated until eight
different flow distributions had been achieved.
Chemical and Physical Characteristics of Polymer-Sewage System
During the tests in which selected polymers were injected into
the six-inch test conduit, statistical sampling was conducted on the
sewage and polymer-sewage combinations (forWSR-301 and Polyox Coag-
ulant-701) to determine any affects of the polymers on sewage, and to
record the specific characteristics of the material used in the flow data
collection.
By its very nature, raw sewage cannot be considered homogeneous;
however, in the project tests, parameter values were controlled as well
as possible so that comparative values could be established within the
data. The test parameters were established from various sewage treat-
ment plant records in the Dallas, Texas, area (Table XV).
56
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TABLE XV
RAW SEWAGE CHARACTERISTICS
OF DALLAS, TEXAS AREA
Total solids, mg/1
Dissolved solids, mg/1
Suspended solids, mg/1
Total volatile solids, mg/1
Total non-volatile solids, mg/1
PH
Chlorides, mg/1
DO, mg/1
BOD, mg/1
Sulfates, mg/1
Total sulfides, mg/1
H2S, mg/1
Ammonia nitrogen, mg/1
Temperature, °F
1,370
1,010
360
780
591
6.5
333
1.0
212
161
2.7
1. 2
0. 4
75
Tests conducted on sewage or polymer and sewage were conducted
in accordance with procedures outlined in Standard Methods for Examina-
tion of Water and Wastewater with measured parameters, including set-
tleable solids, total solids, dissolved solids, suspended solids, pH,
chlorides, hardness, chemical oxygen demand (COD), dissolved oxygen,
specific conductance, oil and grease, and temperature.
The control factor accurately maintained in diluting raw, concen-
trated sewage, to the levels generally found in combined municipal sew-
age, was settleable solids. Recorded data of these tests as they relate
to the flow testing with various polymers and polymer concentrations are
found in Table XVI.
The values of chlorides and calcium-carbonate hardness follow
a narrow consistent range of values (Table XVI) as expected, since these
parameters are primarily derived from the water in the sewage. These
factors do not contribute to or deter the function of the polymers as
friction reducers in overflowing sewer lines.
Values obtained from the tests, which depend upon the electrolytic
nature of the sewage and the polymers (i. e. , pH and specific conduc-
tance), vary erratically with increased polymer concentration; however,
the maximum variation in pH was 0. 69 and the maximum variation in
specific conductance was 32.4 micro-mhos per cubic centimeter.
The tendency for the values of the total solids and dissolved
solids to increase with an increase in polymer concentration was expected
because of the gross quantity of polymer injected.
57
-------
The suspended solid values of the sewage were reduced when
polymers were injected into the model sewer line, with the greatest
reduction obtained with the lower polymer concentration (50 milligrams
per liter). The suspended solids are dependent upon the total solids and
the dissolved solids; therefore, as the polymer solids concentration
increased, the reduction in suspended solids generally decreased
proportionately.
Erratic values were found during the oil and grease testing and
probably occurred because the material tended to coalesce or lump. The
data showed no change with change in polymer concentration.
The COD values increased with increases in the polymer concen-
tration. The test indicated the amount of carbonaceous or organic mater-
ial available for oxidation by a strong chemical oxidant. Thus the analysis
should show increased COD due to inclusion of the polymers (an organic
material) which are, although, a minor part of the immediate biochemical
load upon the oxygen assets of the sewage receiving the polymer injection.
An increase in COD was, in fact, measured in the polymer-sewage
mixture as the polymer concentration was increased. This increase in
COD can be seen by the tabulations shown in Table XVI.
In a typical sewer system, the polymer concentration injected
should be greatly diluted when the flow from a surcharged section of the
collection system merges with the downstream flow from other sections
of the collection system. For example, in one sewer system investigated
during rainy weather, the flow in the restricted section was 9.4 million
gallons per day (mgd). Since the total downstream flow in the system
was estimated at 40 mgd, the polymer concentration used should be
diluted by a factor of four; however, if the polymer injected in a collec-
tion system to reduce the energy required to overcome friction losses
should result in any concentration at the treatment plant, it should be less
than those normally used for coagulation. Thus, the organic load of the
effluent of the treatment plant should not be materially, if at all, affected
by the polymers injected into the collection system.
The dissolved oxygen (DO) values showed definite relationship
to the amount of agitation occurring in the storage reservoir during
testing, and to the temperature of the sewage; however, no correlation
pattern developed between the DO parameter and the polymer injection
concentration. There was some tendency for DO values to be slightly
higher at low temperatures than at higher temperatures, due to the better
oxygen-retention capability of water at lower temperatures.
Most of the test data obtained from measuring the various charac-
teristics showed that there was little affect of the polymers injected
upon the sewage and, for practical purposes, all polymers injected at
various concentrations remained available for friction reduction.
58
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PAGE NOT
AVAILABLE
DIGITALLY
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Six-Inch Flow System Test Results
The results of the six-inch test sewer screening were obtained by
evaluating (under the controlled conditions described in Table XVII) five
of the six selected polymers. One polymer candidate, J-2FP, was not
tested in the matrix because of its ineffectiveness as a friction reducer.
The test results presented were established as a function of the non-
polymered sewage flow rate, sewage characteristic, pressure loss,
temperature, and polymer concentration.
The matrix of test data taken on the six-inch test facility is shown
in Table XVII. Several data points were run repeatedly to insure repeat-
ability of the data.
TABLE XVII
MATRIX OF FLOW DATA USED
Polymer Concentration
Polymer (mg/1)
Temperature
Sewage
Settleable
Solids (ml/1)
AP-30
FR-4
D252
WSR- 301
Poly ox
Coagulant-
701
100, 250 and 500
100, 250, 350 and 500
100, 250, and 500
100, 250, and 500
100, 250, and 500
100, 250, and 500
100,
100,
100,
50,
50,
50,
50,
50,
50,
50,
50,
50,
50,
50,
50,
50,
50,
50,
50,
50,
50,
250,
250,
250,
100,
100,
100,
100,
100,
100,
100,
100,
100,
100,
100,
100,
100,
100,
100,
100,
100,
100,
and 500
and 500
and 500
and 200
and 200
and 200
and 200
and 200
and 200
and 200
and 200
and 200
and 200
and 200
and 200
and 200
and 200
and 200
and 200
and 200
and 200
38
70
90
38
71
90
38
70
90
38
70
90
38
74
90
38
74
90
38
73
90
38
74
90
38
74
90
0
0
0
0
0
0
0
0
0
0
0
0
3
3
3
9
9
9
0
0
0
3
3
3
9
9
9
61
-------
The results of the six-inch sewer section screening tests are pre-
sented graphically in Figures 21 through 53. Examples and an explanation
of how the graphs were derived from actual test data are given in Appendix
C.
Initially the behavior of the polymers in the six-inch system was
observed in water containing no sewage. These tests were performed at
various flow rates, polymer concentrations, and temperatures. For the
purpose of comparison, a flow rate of 300 gallons per minute was chosen
to evaluate the increase in flow rate at constant head pressure. The calcu-
lations of increased flow rate with polymer, as shown in Figures 21 through
53, was accomplished by using flow curves (flow rate versus friction pres-
sure loss) to determine the friction head loss for sewage at 300 gallons per
minute. At this head loss, flow rates for sewage with each of three polymer
concentrations (50 ppm, 100 ppm, and 200 ppm) were determined, and the
percent flow increase calculated as
Flow with polymer - 300 gpm
300 gpm
The polymers selected for testing, did not produce high friction
pressure losses as occurred for sewage without polymer. Therefore, it was
necessary to extrapolate the flow rate that would have occurred for the sew-
age/polymer mixture. Specific concentrations were then chosen for each
polymer based on its cost and the amount of additive required. Based on
the selected polymer concentrations, the results of this analysis indicated
that, over a temperature range of 38°F to 90°F, the polymers ranked in the
following order with respect to flow increase at constant head 1) Poly ox
Coagulant-701, 2)WSR-301, 3) AP-30, 4) D-252, 5) FR-4, and 6) J-2FP.
Concentrations, temperatures and derived flow increases are shown in
Figure 21.
Because of the relatively high concentrations required to achieve
flow increases comparable with the other polymers, J-2FP was not scheduled
for further testing after the ambient temperature run. This polymer additive
was the least expensive of the six additives tested, but its lower cost was
not sufficient to overcome the disadvantages of having to use larger injec-
tion equipment and larger quantities of the polymer.
Although D-252 ranked fourth in the rating, it was not chosen for
further consideration due to the difficulty of on-site injection, as explained
in Section III. The process involved would require batch mixing and thus,
would require more complicated and costly injection equipment. Since this
was the only major disadvantage associated with the additive, a complete
test data matrix was performed. It is believed that, under certain circum-
stances, D-252 could prove to be a contender. One such case might be
where the sewage or sludge is pumped over long distances in forced mains
resulting in high fluid shear rates in the line.
62
-------
140
120
100
$ 80
I
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a
UJ
IT
60
o
40
tr
UJ
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20
?-WSR 301 @ 200 PPM
-POLYOx COAGULANT 701 (3> 100 PPM
o -AP- 30 @ 250 PPM
o -D252 (cb 250 PPM
n-FR-4 @ 250 PPM
X -J-2FP@ 500 PPM
TEMPERATURE F
See example of graph derivation in Appendix.
Figure 21. Comparison of the Effectiveness of Six Additives
in Water as a Function of Temperature.
63
-------
140
120
100
*
k
1
c£ 80
;
CO
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§ 60
o
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UJ
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20
o-o ml/I SETTLEABLE SOLIDS SEWAGE
D-3mi/i SETTLEABLE SOLIDS SEWAGE
SETTLEABLE SOLIDS SEWAGE
35 4O
50
60
70
80
90
TEMPERATURE F
*
See example of graph derivation in Appendix.
Figure 22. Comparison of the Effectiveness of WSR-301 at
200 mg/1 in Sewage as a Fraction of Temperature.
.. 64
-------
140
120
100
o
E
LL)
Q
80
Ld
o 60
Q 40
20
o-O ml/1 SETTLE ABLE SOLIDS SEWAGE
a-3ml/l SETTLE ABLE SOLIDS SEWAGE
£-9 ml/I SETTLEABLE SOLIDS SEWAGE
35 40
50 60
TEMPERATURE
70
80
90
See example of graph derivation in Appendix.
Figure 23. Comparison of the Effectiveness of Poly ox Coagulant-701 at
100 mg/1 In Sewage as a Function of Temperature.
65
-------
S
o
UJ
>
IT
UJ
O
140
120
100
80
co
Lu
K
o
60
o
40
20
o 38 F
a 73°F
a 90°F
2 4 6 8
„ SEWAGE SETTLEABLE SOLIDS mi/i
See example of graph derivation in Appendix.
Figure 24. WSR-301 at 200 mg/1 in Sewage at Indicated
Temperatures, Six-Inch Test Facility.
10
66
-------
140
120
*
k.
100
80
UJ
CO
LJ
cr
0
z
60
o
UL
Q
UJ
>
cr
UJ
Q
40
20
o 38 F
a 73° F
A 90° F
468
SEWAGE SETTLEABLE SOLIDS (mi/D
See example of graph derivation in Appendix.
Figure 25. Polyox Coagulant-701 at 100 mg/1
in Sewage at Indicated Temperatures.
67
iO
-------
140
k.
£
o
Q:
ui
en
<
LU
<2L
U
0
Q
UJ
>
tr
UJ
120
100
(300) gpm
(250)gpm
100 200 300 400
POLYMER CONCENTRATION-PPM
n
See example of graph derivation in Appendix.
Figure 26. AP-30 in Six-Inch Test Facility at 38°F.
500
68
-------
4>
o
CREASE -PERCENT
DERIVED
o
.. (250) gpm
100 200 300 400
POLYMER CONCENTRATION - PPM
See example of graph derivation in Appendix.
Figure 27. AP-30 in Six-Inch Test Facility at 70°F.
500
69
-------
k
1
I
UJ
en
<
LLJ
CC
CJ
o
_l
LL
0
UJ
E
UJ
O
100 200 300 400
„ POLYMER CONCENTRATION— PPM
See example of graph derivation in Appendix.
Figure 28. AP-30 in Six-Inch Test Facility at 90°F.
500
70
-------
k
I
I
UJ
a
UJ
cr
o
o
Q
UJ
>
cr
LU
o
140
120
100
80
60
--(300)gpm
bee
u 100 200 300 400
POLYMER CONCENTRATION — PPM
example of graph derivation in Appendix.
500
Figure 29. FR-4 in Six-Inch Test Facility at 38°F.
-------
fc
I
LL)
o:
u
o
111
>
cr
UJ
140
120
100
80
-(400) gpm
•(350) gpm
-(300) gpm
200
300
400
—
500
See
POLYMER CONCENTRATION- PPM
example of graph derivation in Appendix.
Figure 30. FR-4 in Six-Inch Test Facility at 71°F.
72
-------
k
UJ
GO
<
UJ
tr
o
o
0
UJ
E
UJ
o
140
120
100
80
60
40
20
{400) gpm
•(350) gpm
-(300) gpm
See
O 100 200 300 400
POLYMER CONCENTRATION- PPM
example of graph derivation in Appendix.
Figure 31. FR-4 in Six-Inch Test Facility at 90°F.
500
73
-------
k
UJ
CO
Q
UJ
E
140
120
100
80
60
40
20
7
100
(400) gpm
(350)gpm
,(300) gpm
200
300
400
500
POLYMER CONCENTRATION -PPM
See example of graph derivation in Appendix.
Figure 32. D-252 in Six-Inch Test Facility at 38°F.
74
-------
I4O
Tw
I2O
*
k. 100
tk
. 80
UJ
en
UJ
///
F
II
S
S
/
//'
/ '
X
/
^
/
X
/^
K7^
^^
^^^
s
^*. "
^^
_^
^f^
^^•^^
^^
^^
"^
^ . -
^(400) gpm
-(350) gpm
-(300) gpm
50 IOO 150 200
POLYMER CONCENTRATION-PPM
*See example of graph derivation in Appendix.
Figure 33. D-252 in Six-Inch Test Facility at 70°F.
250
75
-------
140
120
*
^ 100
Of^
uj 8O
UJ
cr
0
2
60
of
0
UJ
> 40
QC
0
20
/
/!
//
/
s
/
/ '
/ X
Ax-
/ ' .r
f*7
/ /
/
x/
x^ .x
^ ...
x ^^
/
x
^^ *
r ^
*r
x" ^X
^
^
^^
^(400) gpm
^(350) gpm
"(300) gpm
100 200 30O 400
POLYMER CONCENTRATION- PPM
*
See example of graph derivation in Appendix.
Figure 34. D-252 in Six-Inch Test Facility at 90°F.
500
I 0
-------
140
120
100
80
UJ
CO
UJ
cr
u
60
o
40
20
(400)
_-
(55))gpm
(300)gpm
200^ 400 600 800
POLYMER CONCENTRATION-PPM
See example of greph derivation in Appendix.
Figure 35. J-2FP in Six-Inch Test Facility at 72°F
1000
77
-------
5
fc
i
UJ
cr
UJ
Q
140
120
100
80
UJ
a
u
60
o
u_
40
20
(300) gpm
50 100 150 200
POLYMER CONCENTRATION-PPM
See example of graph derivation in Appendix.
Figure 36. WSR-301 in Six-Inch Test Facility at 38°F in Water.
250
78
-------
2
Q
UJ
E
UJ
140
120
100
80
UJ
a:
u
60
o
40
20
7
•(300)gpm
•(250)gpm
50 100 150 200
POLYMER CONCENTRATION-PPM
See example of graph derivation in Appendix.
Figure 37. WSR-301 in Six-Inch Test Facility at 70°F in Water.
250
79
-------
140
i
UJ
UJ
cr
o
o
Q
UJ
E
UJ
Q
120
100
50 100 150 200
POLYMER CONCENTRATION-PPM
See example of graph derivation in Appendix.
Figure 38. WSR-301 in Six-Inch Test Facility at 90°F in Water.
250
80
-------
K.
I
Q
LU
E
140
120
100
80
UJ
00
UJ
CE
u
60
40
20
V7
/
,(300)gpm
-(250) gpm
50 100 150 200
POLYMER CONCENTRATION-PPM
See example of graph derivation in Appendix.
Figure 39. WSR-301 in Six-Inch Test Facility
at 38°F in Sewage (3ml/l Settleable Solids).
250
81
-------
K
§
I
\
LLJ
C/>
<
£
o
0
UL
g
100
8
40
20
X
X300) gpm
-(250) gpm
0
POLYMER
100 150 200
CONCENTRATION -PPM
250
See example of graph derivation in Appendix.
Figure 40. WSR-301 in Six-Inch Test Facility at 70°F
in Sewage (3 ml/1 Settleable Solids).
82
-------
Q
LU
140
120
100
80
I
I
I
LU
en
<
LLJ
cr
u
60
o
u.
40
20
7
(300) gpm
—(250) gpm
50 100 150 200
# POLYMER CONCENTRATION-PPM
See example of graph derivation in Appendix.
Figure 41. WSR-301 in Six-Inch Test Facility at 90°F
in Sewage (3 ml/1 Settleable Solids).
250
83
-------
140
120
I
I
UJ
CO
<
UJ
o:
O
G
UJ
E
UJ
O
100
50 100 150
POLYMER CONCENTRATION
*See example of graph derivation in Appendix.
200
PPM
250
Figure 42. WSR-301 in Six-Inch Test Facility at 38 F
in Sewage (9 ml/1 Settleable Solids).
84
-------
NCREASE - PERCENT
o
cr
UJ
o
8
8
/
--{300) gpm
(250) gpm
^0 100 150
POLYMER CONCENTRATION-PPM
*See example of graph derivation in Appendix.
Figure 43. WSR-301 in Six-Inch Test Facility at 70°F
in Sewage (9 ml/1 Settleable Solids).
250
85
-------
140
120
k
I
100
80
UJ
K
o
60
O
u_
Q
UJ
>
cr
UJ
40
20
-(300) gpm
-~(250)gpm
50
POLYMER
100 150
CONCENTRATION
200
PPM
250
See example of graph derivation in Appendix.
Figure 44. WSR-301 in Six-Inch Test Facility at 90 F
in Sewage (9 ml/1 Settleable Solids).
86
-------
140
I
Lu
CO
u
2
O
_l
U.
Q
>
UJ
120
100
(300) gpm
(250) qpm
50 100 150 200
POLYMER CONCENTRATION-PPM
See example of graph derivation in Appendix.
Figure 45. Polyox Coagulant-701 in Six-Inch Test Facility
at 38°F in Water.
250
87
-------
140
I
UJ
UJ
tr
u
O
LL.
O
UJ
x
(300) gpm
(250) gpm
50
POLYMER
100 150 200
CONCENTRATION - PPM
250
See example of graph derivation in Appendix.
Figure 46. Polyox Coagulant- 701 in Six-Inch
Test Facility at 73°F in Water.
-------
2
u
LLJ
>
cc
UJ
a
140
120
100
80
UJ
LD
UJ
ET
U
60
o
40
20
^300) gpm
(250) gpm
50 100 150 200
POLYMER CONCENTRATION-PPM
See example of graph derivation in Appendix.
Figure 47. Polyox Coagulant-701 in Six-Inch
Test Facility at 90°F in Water.
250
89
-------
140
120
K.
£
100
80
UJ
CO
UJ
cc
UJ
Q
40
20
(250) gpm
•(300)gpm
50 100 150 200
POLYMER CONCENTRATION-PPM
See example of graph derivation in Appendix.
Figure 48. Polyox Coagulant- 701 in Six-Inch
Test Facility at 38°F in Sewage
(3 ml/1 Settleable Solids).
90
250
-------
140
120
k.
£
100
80
UJ
CO
UJ
£T
O
60
o
UJ
>
cc
UJ
o
40
20
,(300) gpm
M250)
50 100 150 200
POLYMER CONCENTRATION-PPM
250
See example of graph derivation in Appendix.
Figure 49. Polyox Coagulant- 701 in Six-Inch Test Facility
at 73°F in Sewage (3ml/ 1 Settleable Solids).
-------
140
S
o
I
LU
UJ
cc
o
O
O
U
>
IT
UJ
Q
120
100
50 100 150 200
POLYMER CONCENTRATION-PPM
it
See example of graph derivation in Appendix.
Figure 50. Polyox Coagulant-70 1 in Six-Inch Test Facility
at 90°F in Sewage (3 ml/1 Settleable Solids).
250
-------
140
£
LU
CO
<
LJ
(T
O
O
Q
LU
>
cc
LJJ
Q
120
100
50
POLYMER
100 150 200
CONCENTRATION - PPM
250
See example of graph derivation in Appendix.
Figure 51. Polyox Coagulant-701 in Six-Inch Test Facility
at 38°F in Sewage (9 ml/1 Settleable Solids).
93
-------
140
ro
o
o
o
oo
o
CREASE •- PERCENT
OW I
o>
o
.&
o
DERI
,(300) gpm
(250) gpm
50 100 150 200
POLYMER CONCENTRATION-PPM
See example of graph derivation in Appendix.
Figure 52. Polyox Coagulant-701 in Six-Inch Test Facility
at 73°F in sewage (9 ml/1 Settleable Solids).
250
94
-------
k.
s
Cj
i
UJ
Q
Ld
140
120
100
80
Id
a
o
60
o
40
20
/
/
/
•(300) gpm
50 100 150 200
w POLYMER CONCENTRATION-PPM
See example of graph derivation in Appendix.
Figure 53. Polyox Coagulant-701 in Six-Inch Test Facility
at 90°F in Sewage (9 ml/1 Settleable Solids).
250
95
-------
The four polymers selected for further consideration as a result of
the initial tests performed in the six-inch facility were: Polyox Coagulant -
701, WSR-301, AP-30 and FR-4. Subsequent to this selection, a more
detailed performance evaluation and further testing was done on these four
polymers to provide as much information as possible for incorporation in
the full-scale field tests.
The flow increase of the system using FR-4 was not as great as
that achieved by the other three additives under any of the flow conditions
tested. It can be seen in Figure 30 that the maximum flow increase, approx-
imately 40 percent, occurred at a temperature of 70°F. The additive was
quite sensitive to the temperature of the base fluid as indicated by the
reduction in flow increase at temperatures of 38°F and 90°F.
The optimum concentration of AP-30 was determined to be approxi-
mately 250 milligrams per liter when compared with the base fluid. This
additive varied about six percent in its flow-increasing ability over the
temperature range from 38 to 90°F. The average derived flow increase
obtained by using AP-30 was about 113 percent (2. 13 times original flow).
The advantages of this polymer were its stability over the temperature range
tested and its relative inertness to the sewage. The main disadvantages
were cost and the relatively high concentrations required as compared with
the polyethylene oxide based additives tested. Nevertheless, AP-30 poly-
mer could be induced into the sewer line with relatively inexpensive equip-
ment.
The remaining two polymers tested in the six-inch test facility were
the polyethylene oxides, WSR-301 and Polyox Coagulant-701. These two
polymers were tested in water and controlled sewage concentration of three
and nine milliliters per liter settleable solids. The reactions of WSR-301
and Polyox Coagulant-701 to both temperature and sewage concentration
made the analysis of the test results rather complex (Figures 21 through
25). Both additives, however, were extremely effective with respect to
increasing the flow of sewer systems.
The analysis of the test data for WSR-301 and Polyox Coagulant-
701 showed similar flow characteristics. WSR-301 at 200 milligrams per
liter varied from a derived flow increase of 125 percent (2. 25 times original
flow) at 38°F to a maximum of 135 percent at 70 F then decreasing to 110
percent at 90°F with 9 milliliter per liter settleable solid sewage. The test
data appeared to indicate that three milliliters per liter of settleable solids
had more effect on this additive than did nine milliliters per liter. The
same phenomena with sewage concentration occurred with Polyox Coagulant-
701; however, 701's ability to increase flow varied more with temperature.
At 9 milliliters per liter settleable solids concentration, the derived flow
increase for Polyox Coagulant-701 varied from 125 percent at 38°F to 141
percent at 73°F and then dropped to 117 percent at 90°F.
In general the results showed that polymer effectiveness, to increase
flow at a constant head or reduce the frictional losses, is dependent upon
sewage characteristic and the sewage temperature.
96
-------
Polymer Injection Point Test Results
Tests were performed in the four-inch test facility to determine the
affect of the point of injection with respect to the location of specific pipe
fittings used in sewers. These tests were performed with AP-30, FR-4
WSR-301 and Polyox Coagulant-701. The restrictions tested were of two
general types, such as the long- and short-radius elbows where flow
restrictions occur as a result of flow deformation, and wyes and tee where
flow restrictions occur due to both flow deformation and turbulence.
To facilitate the analysis, the data was normalized before plotting,
which resulted in the definition of a performance index (€. ) that was the
ratio of the flow increase due to injection at point "i" (i = 1 to 4) to
the maximum flow increase experienced. Also, the distance from the
injection point to the restriction is expressed in equivalent pipe diameters,
L/D, where L is the length of the pipe and D is the pipe diameter.
Figure 54 represents the data for all the constrictions tested,
including results of the square sewer line tests, which agreed with the
circular tests. It should be observed that the additive injection point
affect was negligible for all the restrictions tested within the L/D range
used. Even though the smallest L/D tested was 21, it is felt that this
mixing was observed to take place at the restriction itself. It is also
possible that all injection points were so close to the restriction that
none of the results are valid.
The injection point tests were performed to determine how far
upstream it was necessary to inject a polymer in order to relieve a line
surcharged by the junction of other lines which were not surcharged.
Test results showed that location of the polymer injection point is not
critical, and that the polymer slurry need be injected only slightly up-
stream of the surcharged point.
Affects of Solid Concentrations on Polymers
During rainstorms, the heavy flow of fluid through combined sewers
can flush accumulated material off sewer walls resulting in settleable
solids as high as 1, 551 milligrams per liter. Previous tests indicated that
Polyox Coagulant-701 and WSR-301 were affected by solids in sewage,
resulting in a reduction in the amount of derived flow increase obtained.
It appeared that a portion of the polymers used to increase flow was sac-
rificed to coagulate the sewage solids. This same coagulating phenomena
may occur with sand, silt, and sludge during the flushing periods.
Of the six polymers tested, three were significantly better friction
reducers, Polyox Coagulant-701, WSR-301, and AP-30. Of the three best
polymers, two were affected by sewage, (e. g. , some deterioration in fric-
tion reduction performance was noticed when tested in sewage instead of
water). Therefore, these two polymers, Polyox Coagulant-701 and WSR-
301, were tested additionally in sewage with high concentrations of solids
at ambient temperature.
97
-------
I
x
UJ
o
LU
O
<
cr:
cc
UJ
Q.
1.0
0.8
0.6
0.4
o.;
EXTRAPOLATED
REGION
0 20 40 60 80 100
DISTANCE UPSTREAM OF BLOCKAGE (L/D)
Figure 54. Injection Point Affect on Sewage System Flow Constrictions.
-------
Shown in Figures 55 through 58 are the results of the additional
tests using high concentrations of settleable solids and three concentrations
of each polymer, 50 milligrams per liter, 100 milligrams per liter, and 200
milligrams per liter. The flow increase results were obtained by measuring
the flow and pressure drop characteristics and by using a test procedure
identical to early tests except that the sewage was neither heated nor cooled.
In sewage with approximately 1, 500 milligrams per liter of settle-
able solids, Polyox Coagulant-701 at 100 milligrams per liter increased the
derived flow rate of the sewage by 2.05 times the original flow rate for sew-
age without polymer (See Figure 57).
In sewage with approximately 1, 600 milligrams per liter of settleable
solids, WSR-301 at 200 milligrams per liter increased the derived flow rate
of the sewage by 2.4 times the original flow rate for sewage without polymer
(See Figure 58).
It is anticipated that the settleable solids used in this test had the
greatest adverse affect possible on the polymer performance, except in the
instances of sludge movement. The heavy solids concentrations in sewers
normally consist of large percentages of sand and silt which do not tend to
attract the polymers for coagulation like sewage solids. The high concen-
trations of solids are believed to occur for a relatively short period of time
when high sewage flow scours the pipe clean of material that has accumu-
lated since the last heavy flow.
Polymer selection for use in a sewer line should take into considera-
tion the solids concentration in the wastewater. Previous tests showed that
one good flow-increasing polymer, AP-30, was not affected by solids, where-
as Polyox Coagulant-701 was affected more than WSR-301.
99
-------
CL
UJ
o
140
120
100
80
g
O
I
I
UJ
en
<
UJ
en
o
60
o
40
20
o 200mg/l POLYMER
a 100 mg/l POLYMER
o 50 mg/l POLYMER
100 200 300 400
SEWAGE CONCENTRATION-(mg/l)
See example of graph derivation in Appendix.
Figure 55. Percentage Flow Increase vs Sewage Concentration
(mg/l) Polyox Coagulant-701 Polymer.
500
100
-------
INCREASE - PERCENT
oo o ro •&
> o o o o
ou
O
_J
u_
0
S 40
E
UJ
0
20
n
\
D
\
D
\
\\
A \ \
V
\
o 200 mg/l POLYMER
^ 100 mg/l POLYMER
D 50 mg/l POLYMER
t\
s
\
100 200 300 400
SEWAGE CONCENTRATION-(mg/l)
See example of graph derivation in Appendix.
Figure 56. Percentage Flow Increase vs Sewage Concentration
(mg/l) WSR-301 Polymer.
101
500
-------
140
120
100
UJ
UJ
o:
o
o
u_
s
E
LLJ
O
0 mg/l SEWAGE
1500 mg/l SEWAGE
2700 mg/l SEWAGE
100 200 300 400 500
* POLYMER CONCENTRATION-(mg/l)
See example of graph derivation in Appendix.
Figure 57. Polymer (mg/l) vs Percent Increase With a Given
Sewage Concentration, Polyox Coagulant-701 Polymer.
102
-------
140
1600 mg/l SEWAGE
2200 mg/I SEWAGE
3110 mg/l SEWAGE
• 3600 mg/l SEWAGE
100 200 300 400
POLYMER CONCENTRATION-(mg/l)
See example of graph derivation in Appendix.
Figure 58. Polymer Concentration (mg/l) vs Percentage Flow Increase
With Given Sewage Concentration, WSR-301 Polymer.
500
103
-------
SECTION V
FIELD TEST EVALUATION OF POLYMERS
Field evaluation of the use of polymers in sewerage systems con-
sisted of two separate testing operations. The first consisted of testing
an existing large-diameter sewer plagued with a surcharged condition
through the injection of WSR-301 and Polyox Coagulant-70 1 polymers.
The second field evaluation was the injection of polymers into the
raw sewage at the intake of a secondary type treatment plant so that data
on its operation could be obtained.
Large-Diameter Sewer Field Evaluation
Full-scale tests were conducted on a 24-inch diameter concrete
sewer line to determine if the use of polymers resulted in flow phenomena
similar to that obtained during tests on a six-inch diameter model line.
Site Selection. The selection of the large-diameter test line was
based upon the following criteria: 1) frequency of surcharged flow con-
ditions from ground-water infiltration, or inadequacy of line capacity dur-
ing peak daily flows; 2) suitability for installation of temporary manholes,
suitability for instrumentation for measuring flow rates, temperature, and
static head on pipe, and suitability for obtaining sewage samples for lab-
oratory analysis; 3) minimum number of branch lines between the point of
polymer injection and the downstream monitoring point with minimal flows:
4) ease of access with injection equipment; and 5) availability to lab-
oratory facilities.
After considering a number of potential sites, the most ideal site
was determined to be a 24-inch interceptor sewer line in the northern
portion of the City of Dallas collection system. This line is constructed
from 24-inch concrete sewer pipe laid at a grade of 0. 32 percent with the
exception of about 170 feet which is at a 0. 25 percent grade.
The 4, 100-foot test section length receives flow from a 36-inch
interceptor line from the City of Richardson and discharges into a 30-inch
diameter pipe downstream. During peak daily flow periods, this line is
surcharged to depths between four and eight feet above the top of the pipe.
After heavy rainfalls, the increased flow resulting from ground-water in-
filtration is released directly into Cottonwood Creek by a bypass valve.
The frequency and magnitude of surcharged flow conditions influenced the
selection of this sewer as the demonstration site for field evaluation.
Site Instrumentation. Figure 59 delineates the plan and profile of
the pipe section used in the large diameter flow test demonstration, in-
cluding the three temporary manholes installed over the 24-inch line and
one manhole installed over the 36-inch line to permit instrumentation.
105
-------
Figure 59. Plan and Profile of
24-Inch Sanitary
Sewer.
-------
The manholes (Figure 60) were constructed by excavating soil
from over the top of the sewer pipe and installing a section of 5-foot
diameter corrugated metal pipe with the bottom end cut to fit the curva-
ture of the sewer pipe. At each manhole, two 2-inch taps were made in
Figure 60. Monitoring Manhole.
the sewer pipe and 2-inch pipes inserted. Concrete was then placed
around the 2-inch pipes and over the top of the sewer pipe to obtain
a flat bottom. By installing valves and fittings, one of the taps was
rigged to obtain sewage temperature and sewage samples and the other
tap was used to obtain the fluctuations in static head on the line.
Two techniques were used in determining the pressure or static
head on the line. One technique was a simple piezometer constructed of
transparent plastic tube, of sufficient diameter to eliminate capillary
action, fitted in one of the taps so that its end extended below the
minimum anticipated sewage level in the pipe (Figure 60).
rose in the tube until equilibrium was reached, and pressure was obtained
by reading the vertical distance from the meniscus or liquid surface to
the top of the fitting that held the tube in place. The elevation of each
piezometer fitting was obtained and correlated with pipe elevations by
field surveys. Since the specific gravity of sewage is near unity, the
pressure in feet of water could be read directly at the required timed
intervals.
The second technique used a section of six-inch diameter PVC
pipe fitted onto the sewer line tap to form a float well. A spring-driven
water-level recorder (Figure 61) with horizontal chart drum was then
installed over the manhole and float well which provided a stati
stage record versus time.
107
-------
Figure 61. Water Level Recorder.
Sewage temperature was obtained by periodically observing a
dial thermometer mounted through one of the taps. Fresh sewage samples
were obtained through a hose bib fitted through the same tap as the
thermometer.
A number of methods are available for determining flow measure-
ment in pipes or conduits, including weirs, Parshall flumes, tracer
materials, and formulas using depth-of-flow and pipe slope. Because
of the surcharged flow condition and depth of the test section, it was
decided that the use of a tracer material method would be most practical
and economical.
This method of flow measurement requires that a tracer be in-
jected into a stream at a continuous and uniform rate of determined con-
centration. The concentration of tracer material was then measured
downstream from the point of injection after complete transverse mixing
and uniform dispersion through the fluid had occurred.
Although many types of tracers are available for use, a dye,
Rhodamine WT, was used in this study. This dye is essentially non-
toxic, is rapidly dispersed in water, is visibly red in concentrations
above 1. 0 mg/1, and is not readily destroyed by chemical agents.
To determine the flow rate, a concentration of 4800 mg/1 of
Rhodamine WT was injected at a uniform rate of 0. 1 gallon per minute
in manhole "A" shown in Figure 59. A fluorometer equipped with an
automatic recorder was used at the end of the 24-inch test section and
is shown in Figures 62 and 63. The concentration of dye, proportioned
to the flow rate in the sewer, can be calculated from the equation:
108
-------
Q = q
where Q = Flow rate of the stream.
q = Flow rate of dye injection in the
stream at concentration C.
C = Dye concentration at injection.
c = Dye concentration at downstream
measuring station.
Figure 62. Fluorometer.
Figure 63. Fluorometer Recorder.
In order to obtain a continuous analysis of dye concentration,
sewage was pumped from the sewer line through the fluorometer. A small
centrifugal pump was used and fitted with a one-half inch diameter
suction probe which extended through a tap in the pipe. While operating,
suspended solids in the sewage clogged the probe inlet causing the pump
to lose suction, prohibiting flow monitoring. Numerous techniques were
tried to eliminate this operation difficulty; however, none provided a
satisfactory solution to this problem. Because of the plumbing arrange-
ment necessary to provide insertion and removal of the probe in the line
and prevent leakage during high surcharges, screening of the inlet was
not possible.
Also, during the periods the pump was not clogged, the dye con-
centrations recorded varied widely due to the passage of large suspended
solids and small air bubbles through the fluorometer. Therefore, to
determine the dye concentration, the flow-through monitoring mechanism
on the fluorometer was abandoned in preference of individual sewage
samples obtained manually with each sample analyzed separately in the
fluorometer This latter method proved to yield more reliable flow data,
required less operation effort, and eliminated time gaps during which the
flow could not be determined because of pump failure.
109
-------
The concentration of dye in the sewage, c, was determined by cor-
rections to the fluorometer dial reading. The normal background reading,
previously determined for the sewage, was subtracted from the dial read-
ing, which was then modified by a correction factor to compensate for tem-
perature variance between the sewage sample and the calibration sample.
Temperature correction curves for various dye tracers were supplied by the
fluorometer manufacturer. This corrected reading was then converted to
dye concentration by either entering the linear calibration curve of dial
reading versus dye concentration, or by dividing the dial reading by the
slope of the line given in the above plot. If the second method is used,
the previous equation would appear as:
Q = q C where Rj = the corrected fluorometer dial reading
Rf m = the slope of the plot of R, versus dye
m concentration curve.
The dye was mixed with water and stored in a 55-gallon drum, which
was tapped and fitted with a valve and hose connections. A small positive-
displacement pump with 3/8-inch piston diameter was used to pump the dye
from this reservoir into the sewer line and is shown in Figure 64. The in-
jection manhole cover was tapped and a 3/4-inch line fitted through the
tap and connected to the dye pump. The end of the pipe was fitted with a
5-psi check valve which prevented the water level fluctuations from affect-
ing the rate of dye discharge into the line.
Figure 64. Dye Metering Pump.
A summary of the instrumentation installed at each existing and
temporary manhole is listed in Table XVIII. Existing manholes are indi-
cated by letters A, B, and C and temporary manholes by numerals 1, 2,
3, and 4 in Figure 59.
110
-------
TABLE XVIII
TEST LINE MANHOLE INSTRUMENTATION
Manhole
Number
Location
Instrumentation
1 Over 36-inch line 80'
upstream from Sta. 0 + 00.
A Junction of 36- and 24-
inch lines, Sta. 0 + 00.
2 Over 24-inch line. Sta.
3 + 99.
3 Over 24-inch line. Sta.
6 + 43.
B Over 24-inch line at 90°
bend, Sta. 11+48
C Over 24-inch line at 90°
bend, Sta. 13 + 19.
4 Over 24-inch line at
Sta. 15 + 63.
Piezometer read manually,
temperature and sample.
Rhodamine WT and polymer
injection point.
Piezometer with level
recorder.
Piezometer read manually,
temperature, and sample.
Piezometer with level
recorder.
Piezometer read manually.
Piezometer with level recorder,
fluorometer monitor for deter-
mining flow rate and sample.
Polymer Injection Equipment. The design and fabrication of a
polymer injection device was accomplished during the program work, and
consisted of two separate mobile units. One unit contained a cone bottom
tank (Figure 65) with a capacity of 1143 gallons which provided a sealed
Figure 65. Slurry Mixing Tank.
Ill
-------
container for mixing the polymer into a slurry and holding the polymer in
suspension. The tank was equipped with piping arranged so that continu-
ous recirculation of the nonsolvent, isopropyl alcohol, and gelling agent,
klucel H, could be accomplished as the polymers were added, to form the
slurry. This unit was also equipped with a 55-gallon drum of eel
for flushing the injection lines after each use to prevent the drying and
clogging of the slurry in the lines. Adequate flushing of the eductor and
discharge lines was necessary after each injection period.
The second unit actually contained the injection device (Figure
66) and consisted of a gasoline-driven, centrifugal sewage pump with a
capacity of 250 gallons per minute, a six-inch eductor, a rotameter, a
four-inch pipe and fittings, a flexible suction and flexible discharge line.
Figure 66. Injection Unit.
The injection unit was connected to the slurry tank by a one-inch
line fitted with a one-inch magnetic flow meter, recorder and control valve
to regulate the concentration of polymer released to the test line.
eductor was used to provide a vacuum on the tank discharge line which,
coupled with the positive head of the tank, permitted the uniform flow o±
slurry from the tank to be regulated or proportioned by the one-inch
trol valve. In operation, the sewage was pumped from the sewer line
through the eductor which discharges from the eductor nozzle at a h
velocity and entrains the slurry from the tank suction line. The slurry
and sewage were thoroughly mixed by the turbulence in the throat of the
eductor and then discharged back into the sewer line. This flash mixing
of slurry and sewage reduced the tendency of the highly water-soluble
polymers to lump or agglomerate as when slowly added 3 water.
The slurry mixing tank and the injection unit are shown with parts
identified in Figure 67.
112
-------
I,.,
Tank Trailer, 1000 Gallon Capacity
Pump, Gasoline Driven
3 Eductor, 6"
4 Flowmeter, 1"
Base
Flowmeter Readout
3-Way Valve, 1"
Ball Valve, 1"
9 Butterfly Valve, 4"
10 Ell, 4" 90° Long Radius
Ell, 4" 90°
Reducer, 4" x 6"
Blind Flange, 6"
Pipe, 4" x 52" Long
Pipe, 4" x 12" Long
Suction Hose, 4"
Discharge Hose, 4"
Flow Gate, 4" By Pass Vena Contracta
Water Level Indicator
Flushing Solvent Tank
Slurry Line
Figure 67. Field Injection System With List of Part
-------
The injection manhole cover was modified to provide connections
for the suction and discharge lines of the sewage pump and the injector
line (Figure 68). Inside the manhole, four-inch PVC pipe was installed
Figure 68. Injection Manhole Cover at
Manhole "A"
between the pressure manhole cover and the flow line of the sewer pipe.
A pressure manhole cover was necessary because of the magnitude of
surcharge on the line during peak flows. The cover was modified by
cutting holes and welding flanged adaptors to the cover. Butterfly valves
and quick-disconnect couplings were attached to the adaptors. The two
units and operations truck are shown on location in Figure 69.
Figure 69. Units in Operation at Manhole "A1
114
-------
Slurry Composition. As indicated, the polyethylene oxides (WSR-
301 and Polyox Coagulant-70 1) are water soluble; however, dissolving
the polymers requires thorough dispersion of the individual resin particles
during the initial contact with water. As the polymer surfaces begin to
absorb water, a cohesive mass is formed that will dissolve only after
prolonged agitation.
Since adequate polymer dispersion is necessary for complete and
rapid dissolving in water, a method is required for injecting the polymer
into the solvent or water that will keep the polymers in suspension. A
nonsolvent that has been gelled was found to be an effective technique
for injecting the polymers into water. Anhydrous isopropyl alcohol gelled
with klucel H formed the nonsolvent gel used in the field evaluation work
on the 24-inch surcharged sewer.
The technique of dispersing polymer in a slurry can be accom-
plished readily and the slurry is stable for long periods of time (if agitated
daily), which allows use as need occurs. When injected into water, the
polymer slurries form aqueous systems quickly with a minimum of mixing
or agitation. A complete discussion of the technique used in mixing the
slurries is given in Appendix D.
The slurry used in the 24-inch sewer line demonstration consisted
of 69. 25 percent isopropyl alcohol (nonsolvent), 0. 75 percent klucel H
(gelling agent), and 30 percent polymer. The current (April, 1969) unit
costs of slurry components in quantities less than 5,000 pounds are:
isopropyl alcohol, $0. 69 per gallon; klucel H, $ 1. 30 per pound; WSR-
301 polymer, $0.80 per pound; or Polyox Coagulant-70 1 polymer, $1.45
per pound. The cost* of preparing a slurry of WSR-301 is $216.89 per 100
gallons. This material cost is increased by $ 144.50 per 100 gallons if
Polyox Coagulant-701 polymer is substituted for the WSR-301 polymer.
Table XIX indicates the material cost in dollars per hour for injecting the
slurry at 50 mg/1 and 100 mg/1 polymer concentration at the indicated
wastewater flow rates.
TABLE XIX
POLYMER INJECTION COSTS -- DOLLARS PER HOUR
Flow
CFS
1. 12
2. 23
5. 57
11 14
16. 71
22. 28
27 85
33.42
MGD
0.72
1.44
3. 60
7. 20
10.80
14.40
18. 00
21.60
WSR-301
50mg/l
$/hi
13.32
26.64
66.60
133.20
199.80
266.40
333. 00
399. 60
100mq/l
$/Hi
26. 64
53.28
133.20
266.40
399. 60
532.80
666.00
799.20
Polyox Coagulant- 701
50 mg/1
$Ahr
21.56
43. 12
107.82
215. 64
323.46
431.28
539. 10
646.92
lOOmg/1
$/hf
43. 12
86.24
215. 64
431.28
646.92
862. 56
1078. 20
1293.84
115
-------
If the materials are purchased in quantities of greater than 20,000
pounds, the WSR-301 slurry cost can be reduced by 20 percent and the
Polyox Coagulant-701 slurry cost can be reduced by 15 percent.
Instrument Calibration. Prior to beginning full-scale testing of the
friction-reduction process, calibration of the fluorometer, tracer metering
pump, and level recorders was necessary.
The fluorometer, G. K. Turner Model 111, was calibrated by using
Rhodamine WT, distilled water, and sewage obtained from the 24-inch test
line. To convert the relative fluorometer readings to concentrations of a
fluorescent solute, the instrument had to be calibrated by using prepared
solutions of known dye concentration and determining the relation of fluo-
rometer dial reading, Rf value, to the dye concentration. A known concen-
tration of Rhodamine WT was diluted in distilled water at a temperature of
72°F (base temperature). Dial readings were observed for the different con-
centrations of dye and a plot of the fluorometer (R ) versus concentration
was developed.
Before each field test was started, the fluorometer dial readings
for sewage without added tracer was monitored to determine the natural
fluorescence of the sewage (background readings). Corrections, based
on the background readings and the sewage temperature, were applied to
the test data obtained. Temperatures above the base value create dial
readings higher than actual while temperatures lower than the base cause
dial readings lower than actual.
The calculation of flow rate when using the tracer method require
the addition of tracer to the wastewater at a uniform and constant rate. To
obtain this, a small positive-displacement pump was used to regulate the
flow of dye at 0. 1 gallon per minute. The flow rate was calibrated by de-
termining the volume of dye delivered by the pump during a timed period.
The magnetic flow meter on the slurry injection equipment was cal-
ibrated by preparing a chart of discharge rate versus polymer concentration
so that the discharge valve could be adjusted to provide the correct dosage
by reading the magnetic flow meter.
Calibration of the Stevens (Type F) water-level recorders consisted
of setting the recorder with reference to the bottom of a stilling well of
known elevation with respect to the flow line elevation of the sewer at
the installation location.
Demonstration Test Procedure. The line selected for the full-scale
demonstration test was surcharged almost daily, eliminating the need for
predicting periods of peak flow based on rainfall duration and intensity.
The initial step in conducting a test run was the preparation of
slurry containing the friction-reduction additive. After pumping the non-
116
-------
solvent into the tank unit of the injector, the gelling agent was slowly
added and thoroughly mixed with the nonsolvent by recirculating the two
components through the tank with a positive-displacement pump for a
period of approximately 12 hours to insure even dispersement. After the
formation of a gel, polymer was slowly added to the gel while being agi-
tated. Various refinements in mixing the polymer slurry are discussed in
Appendix D.
The formation of a slurry was obtained in one to two hours, depend-
ing on the batch size. Test batches of over 500 gallons were most diffi-
cult to prepare. To facilitate the determination of the rate of slurry dis-
charge from the tank through the magnetic flow meter, a small quantity of
potassium acetate (0.077 percent or about 1. 1 pounds per 200 gallons of
slurry) were added to the slurry to increase the conductivity. In general,
the mixing procedure usually required about 14 hours of preparation prior
to beginning the test; however, it should be noted that this time was re-
duced by four to six hours when the procedures described in Appendix D
were used. The slurry was stable, if agitated periodically, and batches
can be made and stored until needed as an operating practice.
Prior to beginning the injection of a friction-reducing polymer,
flow conditions in the 24-inch test line were analyzed to determine if the
static head on the line was increasing or decreasing, at manhole number 1
(because of increasing or decreasing flow), and if each observation man-
hole in the test section was surcharged, but not an excessive amount
(overflowing top of manhole). If the test parameters were met, a continu-
ous sample of the wastewater was pumped from the test line through the
fluorometer or individual samples collected and analyzed separately for
normal fluorescence determination as required for calibration. Samples
were taken from manhole number 4 for analysis of dissolved oxygen, total
solids, settleable solids, pH, and specific conductance.
While the preparatory tasks were being accomplished, the slurry
was transported to the test site, and the injector and tank units set in
position at manhole A. The 4-inch flexible suction and discharge lines
were connected to the quick disconnect couplings on the modified pres-
sure type manhole cover and on the injector unit. The tank unit was con-
nected to the injector unit by flexible hose and the pump engine started.
The slurry could then be injected into the line when desired by simply
opening the butterfly control valve on the tank discharge line.
Prior to actual polymer injection, the tracer dye was pumped into
the line and the sewage flow rate monitored. Also, water level readings
were started approximately 30 minutes prior to injection, and the ambient
and fluid temperatures were noted at the various manholes.
Based on the recorded flow rate in the sewer pipe and the desired
polymer concentration, the flow rate of slurry from the tank was controlled
by the butterfly valve as monitored by the magnetic flow meter.
117
-------
During the first 15 minutes of slurry injection, piezometer read-
ings were taken at 1-minute intervals so that the initial head reduction
could be detected. After this period, piezometer readings were taken at
maximum intervals of 15 minutes with the time each reading was taken
being recorded at each manhole. After injecting for 30 minutes and 60 min-
utes, grab sewage samples were taken from manholes 1 and 4, and compos-
ited for each sample location.
The slurry was injected until the surcharge was eliminated by re-
ducing the frictional losses sufficiently to carry all of the wastewater with-
in the pipe. At the termination of polymer injection, piezometer readings
were taken at 1-minute intervals for 15 minutes to detect the initial increase
in head, and followed by readings taken at 15-minute intervals until the
flow returned to or near the original surcharged condition. At this time, a
final sample was taken from manhole number 4, completing the demonstra-
tion test procedure.
Test Results and Analysis. The purpose of full-scale sewer line
testing was to demonstrate the similarity of flow phenomena and to verify
the results obtained in the six-inch model sewer line tests. As previously
mentioned, two polymers were tested, WSR-301 and Polyox Coagulant-701
in a gel of isopropyl alcohol and klucel H. The slurry contained 30-percent
polymer (by weight) and was injected into the sewer line at concentrations
of polymer varying between 35 and 100 mg/1. After running one test to re-
fine test procedures, four tests were conducted with each polymer with
varying results and data reliability.
Results from these tests confirm the results obtained from the
small-scale test model in that the frictional resistance to flow can be de-
creased to an extent that the surcharge can be eliminated.
A typical week-day hydrograph of the flow depth in the line at in-
jection manhole 1 is given in Figure 70. Tests were conducted during the
last week of August, the month of September and the first week of October;
the period during the year when rainfall and infiltration of ground water is
minimal in the Dallas, Texas, area. During wet periods, excessive infil-
tration caused overflow of the monitoring manholes and prohibited the col-
lection of test data.
Figure 70 is the plot of the sewer hydrographs obtained on the day
WSR-301 was injected into the line at approximately 80 mg/1 concentration.
The pressure head on the line was reduced approximately four feet through-
out the test section during the one-hour injection period. It is apparent
in Figure 70 that the polymer injection was started as the flow was begin-
ning to decrease (indicated by the decrease in surcharge on the line). As
a result, the polymer reduced the energy required to drive the now which
was initially 6, 500 gpm. This flow rate was increased during the injec-
tion period but only slightly since the hydraulic gradient decreased con-
tinuously as the surcharge dropped. An explanation of the effects of poly-
mers on a gravity flow system is given in Appendix B.
118
-------
' i
FLOW RATE PRIO
TO INJECTION
6500 gpm
AUG. 22, 1968
PERIOD OF POLYMER INJECTION : ONE HOUR
POLYOX WSR 301, 80 mg/l
8A.M. 10 12 2 P.M. 468
TIME -HOURS
Figure 70. Head Reduction Obtained Using 80 mg/l of WSR-301.
2AM
-------
Similar hydrographs for each monitoring manhole are shown in
Figures 71 and 72. It should be observed that at each manhole below
the injection point an increase in head occurred shortly after the additive
was injected and proceeded down the line. This increase in head was
caused by a transient flow phenomenon resulting from reduced boundary
shear stresses or factional losses in the sewage. When the flow volume
in the 24-inch pipe adjusted to the new flow rate, the head dropped
uniformly along the pipe.
In Figure 71, polymer injection was again started as the flow
reached a peak. As a result, the flow rate was only slightly increased
because of the decrease in both the hydraulic gradient and the volume of
wastewater to be carried by the pipe. Similar results were obtained for
the tests presented in Figure 70, however ,. in Figure 72, polymer was
injected while the volume of flow was increasing since the flow history
of the line indicated that peak flow usually occurred between 11:30 a.m.
and 12 noon on week days. As a result of injecting under this condition, a
flow rate increase was obtained in addition to a decrease in the surcharge
or static head. This flow increase was a result of the reduction in the
frictional resistance to flow provided by the polymers and the continued
increase in volume of wastewater to be carried in the pipe.
In each of the tests, injection of polymer was stopped when the
desired results were obtained (reduction of the head on the line to eliminate
a surcharged condition or a pollution source).
Analyses of sewage grab samples were made so that the character-
istics of the sewage could be determined, should the effectiveness of the
friction-reduction additive be considerably less than anticipated (see
Section III of this report for effects of sewage on polymers). In general,
the two additives were as effective as anticipated and only dissolved
oxygen, total solids, suspended solids, pH, specific conductance, and
temperature tests were made in accordance with the procedures detailed
in the Twelfth Edition of Standard Methods for the Examination of Water
and Wastewater. Table XX presents the results obtained for test runs using
WSR-301 and Poly ox Coagulant-701.
As a result of full-scale tests on the 24-inch diameter sanitary
sewer line, the elimination of surcharged flow conditions was possible by
injecting a slurry containing polymer which reduced shear stresses within
the fluid and caused a decrease in the frictional resistance to flow. The
reduction of frictional losses in the test section decreased the static head
required to drive the inordinate flow, resulting in the head drops observed
in the piezometers.
These same flow phenomena were obtained in the six-inch line,
tests conducted in the earlier phases of this program. In these tests,
however, a constant flow rate was maintained and the friction-reduction
effects of the polymer were observed by reductions in static head on the
line. Since constant flow conditions were not obtainable in the field test,
the effects of the polymer slurry were observed by both static head reduc-
tion and slight flow increases, as described in Appendix B.
120
-------
PAGE NOT
AVAILABLE
DIGITALLY
-------
TABLE XX
SEWAGE SAMPLE ANALYSES FOR 24-INCH
SEWER LINE TEST RUNS
Date
Polymer
Concentration
(mrt/n
\*"3 ' -/
Temperature
(°F)
O
Q-
.— **
i— (
o>
6
•— -
j_j ,__) tj>
££,§
CD
3*3 g
CO COO-
ffi
a
Specific
Conductance
( jj. mho)
POLYOX WSR- 301
Aug.
Aug.
Aug.
Aug.
Aug.
Aug.
Aug.
Aug.
Sept.
Sept.
Sept.
Sept.
Sept.
Sept.
Sept.
Sept.
Sept.
Sept.
Sept.
Sept.
Oct.
Oct.
Oct.
Oct.
Oct.
Oct.
22,
22,
22,
22,
22,
22,
27,
27,
3,
3,
4,
4,
20
20
20
20
27
27
27
27
7,
7,
7,
7,
7,
7,
1968
1968
1968
1968
1968
1968
1968
1968
1968
1968
1968
1968
, 1968
, 1968
, 1968
, 1968
, 1968
, 1968
, 1968
, 1968
1968
1968
1968
1968
1968
1968
0
0
0
80
SO
0
0
75
0
40
0
100
0
50
50
0
0
80
80
0
0
0
35
35
0
0
86
87
86
86
87
87
86
87
85
85
84
84
POLYOX
80
82
82
85
82
82
82
85
78
79
80
80
81
80
6.
4.
7.
5.
7.
6.
7.
9.
6.
6.
8.
8.
0
0
2
8
0
4
2
0
8
8
6
8
897
789
919
957
1133
851
844
1178
912
1258
755
1376
172
146
158
122
102
131
228
226
124
216
134
160
7.
6.
7.
7.
8.
7.
6.
7.
7.
8.
8.
9.
7
8
2
3
4
0
5
0
4
0
4
1
1240
1020
1630
1041
834
1017
953
872
962
862
1513
1103
COAGULANT- 701
"O
CD
<0
-Q
t>
^
(0
(0
Q
840
980
1120
885
1421
1938
2168
985
620
780
910
1163
852
1160
112
154
185
108
290
386
415
195
148
196
115
230
178
264
7.
7.
7.
6.
6.
6.
6.
7.
6.
6.
6.
6.
7.
7.
2
1
2
9
9
9
8
3
6
8
7
8
4
1
2510
2660
720
1230
1050
880
680
1100
790
825
925
689
768
510
125
-------
TABLE XX
SEWAGE SAMPLE ANALYSES FOR 24-INCH
SEWER LINE TEST RUNS (Continued)
g
f-l
4-"
(0
s-. •£
||S
Date
Oct.
Oct.
Oct.
Oct.
Oct.
iperature
£uJi S£
8,
8,
8,
8,
8,
1968
1968
1968
1968
1968
0
0
45
45
0
^ aw—
79
80
79
80
80
p
pjE.
Data Not
Obtained
0 0 g
H WO-
930
1133
860
980
760
. ._ • -
-a
0
-o
0 w"^r
W ^H 0>
3 0 g
CO CO v
164
195
132
145
217
ffi
a
7.
7.
7.
7.
8.
ecific
inductance
p. mho)
c
u
0
2
0
1
5
lO-^
1125
1060
739
770
1050
During the various test runs, slurry injection rates. •«mg WSR-
301 and Polycx Coagulant-701, were operated between 35 and 100 milli-
orams per mer as shown in Table XXI. Each concentration used resulted
S a reduction in surcharge, with the smaller concentrations requiring
TABLE XXI
RESULTS OF 24-INCH SEWER LINE TEST RUNS
Time
11:56 AM
12:00 N
12:15 PM
12:30
12:45
12:53
1:00
1:15
1:30
Flow
Rate
(gpm)
6500
6500
6200
-H-
-H-
-H-
*
+
Polymer
Concen-
tration
(mg/1)
August 22,
Start Inj.
80
Approx.
80
Approx.
80
Approx.
80
Stop Inj.
0
0
0
Surcharge Above Top of
in Feet at Manhole
1
2
3
B
Pipe
C
4
1968 - Polyox WSR-301
6.95
6.85
6.30
5.35
3.85
3.25
3.40
3.60
3.85
6.80
6.70
6.20
5.20
3.75
3. 15
3.00
3.65
3.90
"O
0
ro
O
&
ro
ro
O
T3
0
C
(0
4-"
XI
O
ro
4->
to
P
T3
0
-.H
ro
XI
O
ro
ro
P
4.05
A ?o
8.25
3.75
2.45
1.50
-H- -H-
i £,£,
1 . DD
1.70
126
-------
TABLE XXI (Continued)
RESULTS OF 24-INCH SEWER LINE TEST RUNS
Time
2:00 PM
2:15
2:30
2:45
3:00
3:15
3:30
3:45
11:15 AM
11:30
11:45
12:00
12:15 PM
12:30
12:40
9:45
10:00
10:10
10:18
10:28
10:40
10:50
11:00
11:10
10:20 AM
10:35
Polymer
Flow Concen-
Rate tration
(gpm) (mg/1)
August 27,
6000 Start Inj.
6500 75
6000 75
5650 75
-H- Approx.
75
* 75
+ 75
-H- Stop Inj.
September 3,
5600 Start Inj.
6300 40
6700 40
6200 40
-H- Approx.
40
-H- 40
-If Stop Inj.
September 4,
5700 0
5900 Start Inj.
8500 100
8500 100
6400 Stop Inj.
-H- 0
* 0
-H- 0
-H- 0
September 20,
6100 0
6200 0
Surcharge Above Top of Pipe
in Feet at Manhole
1 2 3 B C
1968 - Polyox WSR-301
6.05 6.45 ^ "§
5.10 5.35 .S -S
4.15 4.35 2 2
3.45 3.70 § O
2.90 3.40 ^
0 0
2.30 2.80 * *
1.85 2.40 £ £
1.70 1.80 Q O
1968 - Polyox WSR-301
-a
5.75 5.95 - g
4.80 4.95 4.80 •£
3.65 3.85 3.80 -g
2.95 3.30 3.05 Q
2.25 2.55 2.55 ^
^
1.75 1.95 2.05 v
1.45 1.80 1.75 £
O
1968 - Polyox WSR-301
3. 70 - 73 -a
3.95 4. 15 g g
3.40 3.80 '£ •£
2.60 2.70 £ £
2.10 1.65 O O
2.45 2.60 3 -g
3.05 & 2
3. 70 - ro ro
4. 40 ro ro
Q Q
1968 - Polyox Coagulant-70 1
b. 25 5.65 4.80
6.40 5.70 5.05
T3
Q)
-iH
ro
•M
O
ro
ro
Q
-a
§
•rH
ro
-1-1
O
o
^
ro
4—*
ro
Q
-a
0
a
•r-4
ro
X!
O
•g
;z;
ro
ro
Q
4.40
4. 70
4
3.40
3.55
3.05
2. 50
2. 20
1.75
* -H-
* -H-
—
3.40
2. 25
1. 50
-H- -H-
II 11
Tr Tr
-H- -H-
—
-
3.40
1.80
-tt- *
+ _M_
Tr
1 1 ii
Tr Tr
-
-
3.50
3. 75
127
-------
TABLE XXI (Continued)
RESULTS OF 24-INCH SEWER LINE TEST RUNS
Time
10:50
11:00
11:15
11:30
11:45
12 N
12:15
12:30
12:45
1:00
1:15
1:30
1:45
2:00
Flow
Rate
(gpm)
September
6200
6450
7100
7000
6400
-H-
PM -H-
-tt-
-H-
•H-
-H-
5700
5750
5900
Polymer
Concen-
tration
(mg/1)
20, 1968
Start Inj.
50
45
60
50
Approx.
50
Stop Inj.
0
0
0
0
0
0
0
September 27,
10:00
10:15
10:30
10:40
10:50
1 1 :00
11:10
11:20
11:30
11:45
12:00
12:15
12:30
12:45
1:00
AM 6100
6100
6150
6150
6700
7300
7500
7600
-H-
-H-
N *
*
-H-
-H-
5650
0
0
0
Start Inj
80
75
80
Stop Inj.
0
0
0
0
0
0
0
Surcharge Above Top of Pipe
in Feet at Manhole
1
2 3
- Polyox Coagulant-701
6.
6.
4.
3.
2.
1.
1.
2.
2.
3.
3.
4.
4.
4.
1968
4.
5.
5.
. 5.
4.
2.
2.
1.
2.
2.
2.
3.
3.
3.
3.
October 7, 1968 -
10:30
10:45
5850
5950
0
0
3.
3.
80
20
85
50
60
90
80
30
80
25
75
00
20
35
6.
6.
4.
3.
T3 7
Q) ^'
a 2.
to
0 *
z. *
0 2.
Z 3.
2 3.
Q 3.
3.
4.
15
05
55
45
85
25
*
*
85
22
60
85
95
00
B
C
4
(Continued)
5.
6.
4.
3.
2.
1.
0.
1.
2.
2.
2.
2.
3.
3.
20
70
90
60
35
85
70
75
10
25
55
95
10
20
5.
5.
4.
3.
2.
1.
0.
1.
1.
2.
2.
2.
2.
3.
00
75
30
15
15
55
30
60
90
20
50
85
90
00
3.90
5.90
3.55
2.65
II _M_
TT" Tl
* -H-
il II
TT Tr
-H- *
ll ii
Tr Tr
1. 75
1.85
2. 15
2. 25
2.35
- Polyox Coagulant-701
95
30
50
60
35
90
20
45
00
55
90
20
25
25
20
4.
4.
4.
4.
5.
3.
<]) 2.
.5 i.
2 -H-
8 *
-(—> " *
>2j 3.
5 3'
fO -1'
Q 3.
35
60
80
95
50
05
70
95
-If
*
85
10
25
25
20
4.
4.
4.
4.
6.
2.
2.
1.
1.
2.
2.
2.
2.
2.
2.
05
30
55
65
00
45
10
35
00
20
35
50
60
60
55
3.
3.
4.
4.
5.
2.
1.
1.
0.
1.
1.
2.
2.
2.
2.
60
80
00
15
70
30
90
35
60
90
95
15
25
30
30
CD
5
(0
§
J_J
3
(0
Q
• Polyox Coagulant-701
10
90
3.55 3.
4.20 4.
45
00
2.
2.
35
95
2.
2.
10
90
1.65
2. 15
128
-------
TABLE XXI (Continued)
RESULTS OF 24-INCH SEWER LINE TEST RUNS
Time
11:00
11:15
11:30
11:45
12 N
12:15 PM
12:30
12:45
1:00
1:15
1:30
1:45
2:00
2:15
2:30
Flow
Rate
(gpm)
October
6050
6100
6200
6500
6850
6850
6300
6150
6000
5850
5700
5600
5500
5400
5250
Polymer
Concen-
tration
(mg/1)
7, 1968 -
0
0
Start Inj.
35
30
35
35
40
35
35
Stop Inj.
0
0
0
0
Surcharge Above Top of Pipe
in Feet at Manhole
1 2 3 B C 4
Polyox Coagulant-701 (Continued)
4.65 4.85 4.50 3.70 3.50 2.75
5.35 5.45 4.95 4.35 4.10 3.25
5.60 5.70 5.20 4.70 4.40 3.50
4.45 4.30 4.25 5.20 3.80 4.15
3.45 3.55 3.45 3.50 2.85 2.40
3.00 3.40 3.35 2.70 2.45 1.85
2.55 3.10 3.15 2.50 2.20 1.75
2.25 2.75 2.80 2.30 2.00 -tf -If
1.85 2.45 2.50 2.15 1.70 -H- -H-
1.60 2.15 2.35 2.00 1.35 -H- -H-
1.45 1.95 2.20 1.80 0.70 -H- -H-
•H- + 1.80 -H- -H- 1.05 0.70 -H- -tf
1.65 2.25 1.95 1.55 1.40 -H- -H-
1.85 2.40 2.10 1.75 1.60 -H- -If
2.05 2.50 2.25 1.90 1.70 -H- +
Octobers, 1968 - Polyox Coagulant-701
10:00 AM
10:15
10:30
10:45
11:00
11:15
11:30
11:40
12 N
12:15 PM
12:30
12:45
1:00
1:15
1:30
1:45
2:00
5800
5850
5900
6700
7800
7850
7500
6750
5350
5450
5600
5700
5700
5700
5700
5700
5700
0
0
Start Inj.
45
40
50
45
Stop Inj.
0
0
0
0
0
0
0
0
0
3.55 3.75 3.35 2. 60 2.55 1.95
3.70 3.90 3.50 2.70 2.70 2.10
3.80 4.00 3.55 2.85 2.80 2.20
2.85 3.45 3.00 2.85 2.90 2.75
2.05 2.55 2.35 1.95 1.90 -H- -H-
1.55 2.10 1.85 1.60 1.45 -H- -H-
-H--H- -H--H- -H- -H- 1.30 1.20 -H- *
-H- -If -H- 4f -H- -H- 0.70 0.30 -H- -If
1.65 2.15 1.95 1.45 1.35 -H- -H-
1.85 2. 35 2. 10 1.60 1. 55 -H- -H-
2.00 2.55 2.25 1.70 1.60 -H- *
2.20 2.70 2.40 1.80 1.80 -H- *
2.45 2.90 2.60 1.95 1.95 -If -H-
2.65 3.10 2.75 2.05 2.05 -H- +
2.80 3.20 2.90 2.20 2.15 -H- -H-
2.95 3.35 3.05 2.30 2.25 1.70
3.10 3.45 3.15 2.45 2.30 1.80
-H- Not able to obtain sample-for fluorometer because of equipment failure.
-H- * Surcharge level below sewer line tap.
129
-------
longer time periods to develop the same pressure head drop that was ob-
tained with the higher polymer concentration. From such head drop obser-
vations, it would be reasonable to conclude that extreme surcharged con-
ditions could be eliminated more rapidly by increasing the initial polymer
concentration rate or varying the polymer concentration upward to an amount
that would provide the relief desired. Both polymers were effective in ob-
taining the desired head reduction, although Polyox Coagulant-701 provided
a more rapid head reduction for the same polymer concentration.
The mobil injector unit and tank were operated efficiently by one
person, although with modifications the equipment could be made to operate
automatically.
Wastewater Treatment Plant Tests
Description of Wastewater Treatment Plant. The selection of a treat-
ment plant as a possible test site to measure the effects of polymer addi-
tives on the treatment processes, was conducted by investigating the char-
acteristics of several wastewater treatment plants of cities in the Dallas
Metropolitan Area. Inspection of the treatment plants was conducted to de-
termine how well each plant would meet the following criteria for a good
test site:
The treatment plant had to consist of at least a primary clar-
ification unit, a filtration unit, a digester, and a sludge dry-
ing bed.
The treatment plant should be suitable for installation of tem-
porary flow measuring instrumentation and injection equip-
ment, and for obtaining sewage samples for laboratory
analysis.
The plant should be easily accessible to injection equipment.
Treatment plants considered for the field test site were in the cities
of Garland, Piano, Richardson, Carrollton, Mesquite, and Lewisville, Tex-
as. A summary of the locations investigated along with pertinent informa-
tion is shown in Table XXII.
Investigation of the locations indicated that the Carrollton and
Lewisville treatment plants would require the least amount of polymer to
perform the tests, because the daily flow rate was the lowest of the plants.
In addition, it was determined that the Lewisville plant would require the
least amount of instrumentation.
Using this as a basis, it was recommended that either the Carroll-
ton or the Lewisville treatment plant be selected as the test site to measure
the effect of chosen polymer additives on the treatment process, however,
130
-------
TABLE XXII
INITIAL TEST SITES INVESTIGATED
Location Avail-
City able
Cost of
Addi-
Instru- tional
Influent ments Instru-
Flow Line Already ments
(mgd) Size
Esti- Travel
mated Distance
Polymer to Plant
In Place Required Cost
Miles
Carrollton yes 0.8 10"
Garland yes 10.0 48"
$12, 334 $ 5,446
Parshall 27,000+ 14,630
Flume
10
34
Piano
Richardson
Mesquite
Lewisville
yes
yes
yes
yes
1.
2.
--
0.
1
0
-
6
1
5"
18"
15"
-
2
-
1"
Parshall
Flume
Parshall
Flume
Parshall
Flume
Weir
30,
44,
9,
6,
000+
560
163
434
7,
9,
9,
5,
540
420
420
500
10
4
26
25
it was felt that the Carrollton plant might not produce meaningful data and
therefore, was not chosen because considerable sewage was bypassed dur-
ing rainstorms and peak flow periods during the day, and because of the low
efficiency in operation.
The Lewisville plant lies within the eastern city limits of the city
and south of Garza-Little Elm Reservoir. This plant receives municipal sew-
age through a 21-inch vitrified clay pipe. The plant is composed of the fol-
lowing units: comminutor.wet wel],and raw sewage pumping station equipped
with one 1000 gall on-per-minute and one 500-gallon-per-minute pump, clar-
igester, trickling filter, and two oxidation lagoons. The 500-gallon-per-
minute pump serves as a standby unit to handle peak inflow rates.
The 40-foot-diameter clarigester performs a dual-function. The top
portion of the unit provides primary sedimentation with a 2-hour detention
period and the lower portion provides anaerobic digestion of the solids re-
moved in the upper unit. The digester has a six-inch sludge withdrawal line,
at the bottom, that discharges onto sludge drying beds. Raw sewage is pump-
ed into the center of the clarigester two feet below the water surface and
empties radially into the periphery collection trough. The clarigester is e-
quipped with a surface scum skimmer, a settled sludge rake, a digester
scum breaker, and a digester sludge rake.
Secondary treatment units consists of a 100-foot diameter trickling
filter with a 6-foot sidewall depth with the wastewater applied by a four-
131
-------
arm distributor. From the trickling filter, the effluent flows into the oxidation
lagoons. A schematic of the plant layout and piping are shown in Figure 73.
Site Equipment and Instrumentation. Since the Lewis ville treatment
plant was a straight-line system, only one flow-measuring device was nec-
essary to measure the flow through all of the units. The desired flow meas-
urement was obtained by adapting the six-inch Foxboro Magnetic Flow Me-
ter, used during the model sewer line testing, to the 10-inch cast iron clar-
igester influent line.
The polymer injector used for the 24-inch sewer line demonstration
was also used for the treatment plant. Some modifications to the slurry
feed system were necessary before the injector system would feed the proper
rate of slurry because much larger slurry injection rates were used on the
full-scale sewer line tests. Slurry injection rates were controlled by a
small-capacity positive displacement pump driven by a variable speed
electric motor instead of the vacuum provided by the eductor of the injec-
tion system. Figure 74 is a schematic diagram that shows the entire injec-
tion system used in treatment plant testing.
Since the raw sewage pump had a capacity greater than the raw
sewage influent rate, the pump operated only 50 to 67 percent of the time.
An operation time of 80 to 90 percent appears to be more desirable since
nonsolvent flushing should be held to a minimum. The raw sewage pump
discharge was fitted with a gate valve which allowed some flow adjustment
to the treatment plant. As part of the testing procedure, the 1,000 gpm pump
was throttled to obtain a flow of 700 gallons per minute and a longer opera-
tion time. The slurry injection rate was set proportionately to the raw sew-
age pump rate to achieve the proper polymer concentration in the sewage.
Polymer Slurries Used. Since the injection pump could only discharge
as low as 0.07 gallon per minute with any degree of accuracy, the polymer
content of the slurry was adjusted so that the injection rate would be in the
more accurate pump range. For a polymer concentration of 50 milligrams
per liter in the sewage, a slurry was used that contained 20 percent polymer
powder. With this polymer content, the suspension capability decreased
in the nonsolvent and therefore, the percentage of klucel H (gelling agent)
was increased to one percent to offset the settling conditions. The solids
content was altered for even lower polymer concentrations. Table XXIII
describes the type of slurry used for three polymer concentrations and the
slurry injection rates.
TABLE XXIII
TREATMENT PLANT SLURRY COMPONENTS
Polymer
Concentration
in Sewage
(mg/1)
50
25
10
Polymer
(%)
20
10
10
Slurry Components
Gelling
Agent Non Solvent
(%) (%)
1
1.25
1.25
79
88.75
88.75
Slurry
Injection
Rate
(gpm)
0. 208
0. 208
0.083
132
-------
I,.
1
LEWISVILLE WASTEWATER
PLANT LAYOUT
-------
SLURRY
RESERVOIR
•VALVE
SLURRY
PUMP
CO
NONSOLVENT
EOUCTOR
UJ
UJ
CO
s
I
0.
+
I
111
CO
NONSOLVENT
PUMP
NON-
SOLVENT
RESERVOIR
VALVE
WET
WELL
WET WELL
PUMP
ACTUATOR
RELAY
SWITCH
1
1
ELECTRIC
POWER
UI5V)
ELECTRIC
POWER
(II5V)
FIGURE 74- SCHEMATIC OF SLURRY INJECTOR SYSTEM USED FOR
TREATMENT PLANT TESTS
134
-------
Since cities using the polymer injection system may use one or
several injectors, the test program to determine the effect of the polymers
on treatment plants was designed to be conducted with a range of polymer
concentrations, and the same two polymers (Polyox Coagulant-701 and
WSR-301) that were injected into the 24-inch sewer line were injected
into the wastewater at the Lewisville treatment plant.
Wastewater Treatment Plant Test Procedure. Each plant testing
period of 24 hours was separated by at least 48 hours to allow the plant
time to return, in general, to normal conditions. The test program was
designed to have a matrix of nine tests (three tests for each polymer, one
without polymer before the first polymer was injected, one without polymer
between the two polymer operations, and one following the second polymer
injection).
A reliable influent hydrograph for an average day was needed to
determine 1) the quantity of slurry needed for a 24-hour operation, 2) the
most desirable time to begin testing and polymer injection, and 3) when to
take samples and what sample quantities were needed for preparing compos-
ite samples. Since available influent flow data was lacking influent hydro-
graphs were developed by conducting 24-hour flow studies. Flow rates
were computed by utilizing the magnetic flow meter installed, the number of
on and off cycles of the 1000 gpm lift pump, wet well dimensions, and time
required for the sewage level to rise a determined distance in the wet well.
During the plant tests program planning stage, one complete 24-hour
flow study was made and a hydrograph plotted. The first flow study was
conducted in December, 1968 (several weeks after any measurable rain)
and was followed by several spot checks at later dates to insure a proper
influent hydrograph. Two additional 24-hour flow studies were made follow-
ing heavy rainfall periods that occurred during a break in the testing program.
One study was made in February, 1969, six days after extremely heavy rain-
fall. The results of these two studies differed only slightly.
The positive displacement pump was connected to the variable speed
drive intake hoses, and discharge lines, and the pump's capacity at various
revolutions per minute was calibrated. The time required to pump a known
volume of 20 percent polymer slurry for each dial setting on the variable
soeed drive, produced a calibration curve of discharge rate (gpm) versus
revolutions per minute (rpm). In addition, a curve of slurry injection rate
versus discharge rate for various concentrations of polymer in sewage was
plotted to aid in the proper injector dial selection.
The evaluation of polymer effects on sewage and wastewater treat-
ment was conducted by measuring the parameters that would yield the most
Significant information on the performance ^^r^™^,^"^!*^
tricklinq filter, and the oxidation ponds such as total solids, dissolved
soUds suspended solids, settleable solids, BOD, COD, dissolved oxygen,
and pH.
135
-------
All analyses were made in accordance with the procedures outlined
in the Twelfth Edition of Standard Methods for the Examination of Water and
Wastewater.
Sewage sampling was done in such a manner as to provide the max-
imum data with a minimum of redundancy in testing. Five locations along
the sewage treatment process were chosen to insure selective sampling:
Wet Well (Station I). This point did not
have any polymer, and provided raw
sewage background data.
Clarigester Inflow (Station II). Raw
sewage and polymer mixed.
Clarigester Outflow (Station III).
Completion of primary treatment.
Trickling Filter Outflow (Station IV).
Completion of first stage of secondary
treatment.
Oxidation Pond Outflow (Station V).
Completion of secondary treatment.
The tests for dissolved oxygen and pH were conducted at the sewage
treatment plant during the test runs. For the remaining tests, composite
samples were made and refrigerated until testing could be done in the lab-
oratory. The time period for composite number one was from 7:30 a.m. to
5:00 p.m. , since it was assumed that the raw sewage characteristics would
remain fairly constant over that period. Composite number two was obtained
from 5:00 p.m. to 2:00 a.m. the next morning. For the remaining time dur-
ing the 24-hour run (2:00 a.m. to 7:30 a.m.), no samples were obtained
since recirculation was employed during this period to maintain a satisfac-
tory operating rate for the trickling filter distributor arm.
Both composites consisted of five sampling times spaced equally
apart. The quantity of each sample was proportional to the flow rate at
the time each sample was obtained, and was proportioned such that the
total volume of each composite was one gallon as listed in Table XXFV.
Each test run was begun at approximately eight o'clock in the morn-
ing and terminated 24 hours later with polymer being injected for at least
two hours before any samples were taken. The waiting time before sampling
was based on a retention time study made with dye tracers which showed
that within one hour after a Rhodamine dye was placed in the wet well,
traces of the dye were picked up in the trickling filter effluent.
After the 1:30 a.m. sample was taken, the recirculation valve was
opened at the secondary oxidation pond, and periodically increased to
correspond with the decrease in raw sewage influent. As the influent rate
136
-------
TABLE XXIV
TREATMENT PLANT TEST-RUN
SAMPLING TIMES AND AMOUNTS
~~~ ~ ~ Sample Volume Composite Sample
Sample Number Time (ml) Number
1
2
3
4
5
6
7
8
9
10
10:00 a. m.
12:00 noon
2:00 p. m.
4:00 p. m.
5:30 p. m.
7:30 p. m.
9:30 p. m.
11:30 p.m.
1:30 a. m.
8:00 a. m.
845
860
830
780
715
870
880
835
485
555
1
1
1
1
2
2
2
2
2
1
increased during the early daylight hours of the morning, the recirculation
was decreased until raw sewage influent rate was sufficient to keep the
plant operating, usually between 7:00 and 7:30 a.m. To complete the 24-
hour test the last sample was taken at 8:00 a.m.
Before each 24-hour test period could begin, a number of changes
had to be made in the plant's operation: 1) if recirculating had been em-
ployed during the night hours, the valve at the secondary oxidat ion pond
had to be closed; 2) the wet-well pump was throttled down to 700 gallons
per minute; 3) all sampling locations were cleaned and the slurry inject ion
system was connected and placed into operation when polymer tests were
conducted.
To insure proper injection rates and functioning of the injection
equipment, surface level readings were taken constantly at the slurry
•
c
FiEc^^^
tie plant was?eturned to normal operating conditions. All composite sam-
ples were rushed to the laboratory for analysis.
Test Results and Analysis. The purpose of the wastewater treatment
tests was to determine what effects the use of polymers in a sewer system
would have upon the plant's operation and efficiency.
The testing program was interrupted by an unexpected breakdown
in the cLrigester sUrrTng mechanism after one non-polymer run and one
polymer inaction test (50 mg/D had been completed in January, 1969.
137
-------
The City of Lewisville decided not to repair the malfunction, but to utilize
the clarigester as an Imhoff tank since a similar breakdown during the
summer of 1968 required several months to complete the repairs. Rather
than wait for the City to repair the plant, or select a new treatment plant
to complete the test program, the FWPCA suggested that meaningful re-
sults might be obtained by using the clarigester as an Imhoff tank. During
the interim from plant breakdown to approval to proceed with testing
operations (March, 1969) sludge was drained from the clarigester by the
City. During this time, the sewage samples were analyzed and data
obtained during the first two runs was evaluated.
Results of the one polymer injection test completed agreed with
the results from the laboratory tests, i. e. , injecting polymer slurry into
a treatment plant system did not adversely affect treatment processes.
On the other hand, this one test provided no conclusive evidence that
settling rates or filtration rates were improved (percent removal of settle-
able and suspended solids and BOD are shown in Table XXV); however, a
definite increase in suspended solids was noted. Performance of the
clarifier was well below that expected for a primary treatment plant where
50 to 60 percent of the suspended solids and 30 to 35 percent of the BOD
should be removed.
TABLE XXV
PERCENT REMOVAL OF APPLIED LOADING IN CLARIGESTER TEST SERIES 1
Settleable Suspended Polymer
Solids Solids BOD Concentration
Non- Polymer
Polyox Coagulent-701
21
20
5
15
19
21
50
The data for the first two tests are tabulated in Tables XXVI and
XXVII. The data indicates very little BOD removal in the trickling filter,
with the majority being removed in the oxidation ponds.
The second series of tests were initiated during the middle of March,
1969, after the two flow studies were performed following heavy rains. The
treatment plant had been in modified operation approximately one and a half
months when the second series of tests began. The stirring mechanism was
repaired during late February although many of the scum rods had been re-
moved, producing a plant operation that was not the best. In addition, it
was noted that very little slime or zoogleal growth or film was present on
the rocks of the trickling filter. Below is a summary of the tests performed
during the second series:
1) Non-polymer: March 13-14, 1969
2) 10 ppm of Polyox Coagulant-701: March 24-25, 1969.
138
-------
TABLE XXVI
LEWISVILLE SEWAGE TREATMENT PLANT STUDIES
Non-Polymer Run
Dec. 26-27, 1968
Oo
NO
Sample
Identi-
fication
I
II
III
IV
V
Temp.
(F)
62
61
62
62
58
Total
Solids
(mg/1)
1576
1578
1590
1479
1468
Dissolved
Solids
(mg/1)
1371
1371
1379
1376
1377
Suspended
Solids
(mg/1)
205
207
191
103
91
Settleable
Solids
(mg/1)
228
228
180
168
153
COD
(mg/1)
423
426
315
438
528
BOD
(mg/1)
175
188
152
148
73
D.
1
1
2
4
5
O.
.75
.75
.5
.75
.6
PH
7.4
7.4
7.4
7.7
7.6
TABLE XXVII
LEWISVILLE SEWAGE TREATMENT PLANT STUDIES
Polymer Run (50 ppm Polyox Coagulant 701)
Jan. 6-7, 1969
Sample
Identi-
fication
I
II
III
IV
V
Temp.
(UF)
61
61
59
59
55
Total
Solids
(mg/1)
1572
1660
1594
1522
1510
Dissolved
Solids
(mg/1)
1450
1482
1458
1440
1473
Suspended
Solids
(mg/1)
142
178
136
82
37
Settleable
Solids
(mg/1)
224
232
185
170
135
COD
(mg/1)
488
828
630
450
146
BOD
(mg/1)
98
168
132
113
53
D.O.
2.3
1.5
1.65
5. 1
2.6
pH
7.4
7. 55
7.4
7.7
7.6
-------
3) 25 ppm of Polyox Coagulant-701: March 27-28, 1969.
4) Non-polymer: March 31 and April 1, 1969.
Analysis of the data disclosed that plant efficiency had not im-
proved any since prior to the breakdown when initial tests were conducted.
Sludge removed from the clarigester, normally every six to eight
weeks, to the sludge drying beds had the color and odor characteristic of
septic and undigested sludge. Moreover, during the testing, strong bubbl-
ing action occurred on the surface of the clarifier as a result of gases es-
caping from the digester through cracks existing in the floor of the clarifier.
It was theorized that grease build up in the ceiling of the digester had
plugged the gas collection chamber and gas could not escape. Also, over
the years that the plant has been in existence, the depth of the primary
oxidation pond has greatly reduced from the design depth of three feet, as
islands of solids deposits are visible in a number of places. The percent
removal of settleable solids, suspended solids, and BOD are shown in
Table XXVIII.
A tabulation of the results of the second series of tests are given
in Tables XXIX to XXXII. Results of the second series of tests indicate
trends similar to those found in the first series, differing only in the raw
sewage loading. If the most reliable settleable solids data is averaged
for all the test operations, the percent removed in the clarifier is 23 per-
cent (7 percent through the trickling filter, and 16 percent through the oxi-
dation ponds). The BOD content of the final effluent was lowest for the
last two polymer runs, except for one non-polymer test. The final COD
content of the effluent, ranged between 140 mg/1 and 170 mg/1, except
for the one non-polymer test, with the initial clarifier loading in COD
varying from 425 mg/1 to 940 mg/1.
Although no definite improvements in filtration and sedimentation
rates were detected while injecting the polymer into the sewage, it should
be noted that no adverse effects developed under the conditions of polymer
applications at the Lewisville plant.
TABLE XXVIII
PERCENT REMOVAL OF APPLIED LOADING IN CLARIGESTER
TEST SERIES 2
Settleable Suspended Polymer
Solids Solids BOD Concentration
Non-Polymer (l)
Non- Polymer (2)
Polyox Coagulant-701
Polyox Coagulant-701
24
33
30
32
31
24
37
24
34
26
36
2
— —
--
10
25
140
-------
TABLE 300k
LEWISVILLE SEWAGE TREATMENT PLANT STUDIES
Non-Polymer Run: March 13-14, 1969
Sample
Identi-
fication
1-1
l-II
l-III
1-IV
1-V
2-1
2-II
2 -III
2-IV
2-V
c
c£ I
o n
£ III
& IV
<: V
Temp.
(°F)
60
59
58
57
56
60
59
60
58
56
60
59
59
58
56
Total
Solids
(mg/1)
1613
1578
1490
1447
1443
1580
1610
1508
1459
1376
1597
1594
1499
1453
1410
Dissolved
Solids
(mg/1)
1445
1417
1389
1368
1370
1389
1413
1420
1416
1371
1417
1415
1405
1392
1371
Suspended
Solids
(mg/1)
168
161
101
79
73
191
197
88
43
5
180
179
94
61
39
Settleable
Solids
(mg/1)
239
251
168
152
146
224
212
185
179
149
232
232
177
166
148
COD
(mg/1)
470
477
394
239
146
532
749
488
279
167
501
663
441
259
157
BOD
(mg/1)
150
200
70
10
30
208
180
180
80
60
179
190
125
45
45
D. O.
(mg/1)
1.8
1.4
2.7
5.8
6.2
2.2
2. 1
3.2
5.2
8.5
2.0
1.8
3.0
5. 5
7.4
PH
7.3
7.2
7.4
7.6
7.7
6.9
7. 3
7. 3
7.6
7.7
7. 1
7.25
7. 35
7.6
7.7
-------
TABLE XXX
LEWISVILLE SEWAGE TREATMENT PLANT STUDIES
Polymer Run (10 ppm of Polyox Coagulant 701)
March 24-25, 1969
Sample
Identi-
fication
i-H
Q) T
w II
O TTT
Q. i11
£ IV
£> I
w II
8, ni
S IV
<3 v
u II
° III
D> IV
<: V
Tejnp.
(F)
58
58
58
57
54
60
59
57
58
54
59
58
58
58
54
Total
Solids
(mg/1)
1528
1659
1392
1262
1273
1428
1419
1434
1363
1259
1478
1539
1413
1313
1266
Dissolved
Solids
(mg/1)
1326
1360
1290
1225
1211
1358
1396
1410
1359
1254
1342
1378
1350
1292
1233
Suspended
Solids
(mg/1)
202
299
102
37
62
70
23
24
4
5
136
161
63
21
33
Settleable
Solids
(mq/1)
248
302
175
135
132
225
244
204
192
134
237
273
190
164
133
COD
(mg/1)
522
818
469
227
162
424
552
421
235
175
473
685
445
231
169
BOD
(mg/1)
80
155
85
25
10
92
120
90
55
15
86
138
88
40
13
D.O.
(mq/'l)
1.3
1.9
2.9
6.5
5.4
2. 1
2.0
2.8
6.3
8.7
1.7
1.9
2. 8
6.4
7.0
pH
7.0
7.4
7. 3
7.4
7.4
7.3
7.4
7. 4
7.7
7. 7
7. 15
7.4
7. 35
7. 55
7.55
-------
u>
TABLE XXXI
LEWISVILLE SEWAGE TREATMENT PLANT STUDIES
Polymer Run (25 ppm of Polyox Coagulant 701)
March 27-28, 1969
Sample
Identi-
fication
Composite 1
Composite 2
c
tf
t_i
o
n-i
6>
>
I
II
III
IV
V
I
II
III
IV
V
I
II
III
IV
V
Temp.
(F)
62
63
62
61
61
62
61
63
62
63
62
62
62
62
62
Solids
(mg/1)
1544
1574
1497
1389
1344
1538
1542
1510
1442
1324
1541
1558
1504
1416
1334
Dissolved
Solids
(mg/1)
1337
1415
1391
1342
1305
1344
1383
1422
1431
1317
1341
1399
140?
1387
1311
Suspended
Solids
(mg/1)
207
159
106
47
39
194
159
88
11
7
200
159
97
29
23
Settleable
Solids COD
(mg/1) (mg/1)
240
258
179
175
146
237
249
167
176
137
239
254
173
176
142
547
942
686
446
147
473
947
906
707
135
510
945
796
572
141
BOD D. O.
(mg/1) (mg/1) PH
70
95
65
25
5
50
80
95
55
20
60
86
80
40
13
2. 1
2.5
3.0
5.7
10.4
1.7
2.0
2.2
4.3
12.1
1.9
2.2
2.6
5.0
11.2
7.5
7.6
7.4
7.7
8.0
7.1
7. 3
7.2
7.3
8. 1
7.3
7. 5
7. 3
7. 5
8. 0
-------
TABLE XXXII
LEWISVILLE SEWAGE TREATMENT PLANT STUDIES
Non-Polymer Run: March 31 - April 1, 1969
Sample
Identi-
fication
Composite 1
-------
SECTION VI
ECONOMIC ANALYSIS OF POLYMER USE
The Keen Branch Basin Sewer in Garland, Texas, was chosen for the
economic analysis because of its history of frequent overflow, and because
the City of Garland had plans for the development of a relief sewer which
would yield specific cost data.
Figure 75 provides the general orientation of the study line which
lies in the northwest section of the city where sewer construction requires
rock excavation. The general slope of the Keen Branch is from west to east
into the Duck Creek outfall sewer. Geologically, the black plastic clay
soil overlays with a minimum cover of Austin chalk.
The area served by the existing sewer is not presently totally devel-
oped but, after total development occurs, the drainage basin will have ap-
proximately 1393 acres in residential and industrial development and about
304 acres in apartments and commercial establishments for a total of 1697
acres, or 2. 65 square miles.
After complete development, design calculations indicate that at the
system's upper end, two 10-inch sewers and one 6-inch sewer will contrib-
ute to the dual-line system a peak inflow of 4. 1 million gallons per day. By
the time the flow reaches Shiloh Road, the total flow in both sewer lines
will be 9. 6 mgd.
The old sewer line consists of 15-inch diameter clay sewer pipe,
constructed at two different time periods. Initial construction was from
the Duck Creek interceptor to Shiloh Road, and the secondary construction
was from Shiloh Road to Yale Drive. In general, the old sewer invert or
flow-line elevations rose from 521.40 feet at the Duck Creek sewer to
612.85 feet at Yale Drive or a total rise of 91.45 feet in a length of 13,010
feet for an average slope of 0.0039.
Existing lateral connections are such that the two lines are inter-
connected at several locations west of International Street, but east of
this area the physiological development of the area and the topography
precluded any interconnections of the two lines.
The new relief sewer will be constructed of 24-inch, 21-inch, 18-
inch, and 15-inch diameter pipe and will empty into the Duck Creek out-
fall, downstream from the existing sewer line location.
The problem section in the existing 15-inch sewer is just west of
Shiloh Road where the minimum slope changes from 0. 0078 to, 0. 00326 for
a distance of 1136. 6 feet prior to an increased slope of 0.0060. The old
sewer, when flowing just full on the 0 00326 slope has a capacity of
only 3. 99 cubic feet per second (cfs), by using a selected Manning s n
valve of 0.012 based upon the condition and alignment of the sewer.
145
-------
KEEN BRANCH
SEWER
RELIEF
SEWER
KEEN BRANCH SEWER
AND RELIEF SEWER
— EXISTING SEWER LINE
— PROPOSED SEWER LINE
Figure t-5. Sewer Line Location Used in Cost-Benefit
Analysis in Garland, Texas.
146
-------
If the 15-inch diameter pipe in this 1136. 6 foot section is consid-
ered as just overflowing at both the upstream and downstream manholes,
the pipe would have a capacity of 6. 59 cfs as a result of the increased
slope of the hydraulic gradient.
Before considering the specific costs of the relief sewer and the
polymer injection on an average annual basis, it should be observed that
no attempt was made to economically evaluate the indirect benefits of re-
ducing sewage overflows onto streets and into creeks. The indirect eco-
nomic benefits include the reduction of damage from sewage entering homes
and businesses and the elimination of health hazards to individuals and
the community.
Relief Sewer. The relief sewer was designed to consist of 2698 feet
of 24-inch, 4315 feet of 21-inch, 3550 feet of 18-inch, and 2935 feet of
15-inch diameter clay tile pipe as shown in Table XXXIII. This table gives
the tabulation of the winning bid for the construction of the sewer. Grades
on the new line vary from 1. 00 to 0. 40 percent with most of the line located
in the Keen Branch.
Recently, the City of Garland sold revenue bonds, to be amortized
over a 30-year period at 5. 7845 percent interest, to finance construction
of several water utility projects, including sewers. This rate of interest
and amortization period was applied to the Keen Branch Relief Sewer to
provide the calculations shown in Table XXXIV.
The low bid of $394,861. 15 was used in making the calculations
for Table XXXIV, along with an engineering fee of $21, 717. 36 and an esti-
mate of $6,000.00 for expenses that the City of Garland would incur for
inspection and other items in conjunction with project construction. The
resulting cost was $422, 578. 51, which was divided into 29 equal parts
of $14,085.98 and one part of $14,086.09. The interest rate was applied
to give the results shown in Table XXXIV.
A review of the City of Garland maintenance and operation costs
for 1967-68 yielded that $131,689 was spent on the 279.9 miles of sewers.
The costs averaged $470 per mile of sewer per year. Applied to the length
of the Keen Branch, its average cost per year will be approximately $ 1202.
Normally, such a project is under maintenance bond for the first year and
maintenance costs are low in the initial service years and increase with
age. So, by using $ 1202 as an average cost, the annual expenditure would
vary from zero the first year to about $ 2400 in the thirtieth year. Therefore,
if a $70 per year increase in maintenance cost is assumed, an operation
and maintenance cost will result as tabulated in Table XXXIV.
By combining all costs involved in constructing the new sewer line,
the average annual project cost over a 30 year period is $27, 309. 98.
Polymer Injection. Cost relative to the use of the polymer injection
method of eliminating surcharges in sewers include equipment costs, mate-
rial costs, and labor costs for both the production of the slurry and the
147
-------
TABLE XXXIII
KEEN BRANCH CONTRACT BID TABULATION
Item
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
Description
6- inch VCT 0'-6'
6-inch VCT 6'-8'
6-inch VCT 8'-10'
8- inch VCT 0'-6'
8-inch VCT 6'-8'
8-inch VCT 8'- 10'
8- inch VCT 10'- 12'
15- inch VCT 0'-6'
15- inch VCT 6'-8'
15- inch VCT 8'-10'
15- inch VCT 10'- 12'
15- inch VCT 12'- 14'
15- inch VCT 14'- 16'
18- inch VCT 0'-6'
18- inch VCT 6'-8'
18- inch VCT 8'-10'
18- inch VCT 10'- 12'
21-inch VCT 0'-6'
21-inch VCT 6'-8'
24- inch VCT 0'-6'
24- inch VCT 6' -8'
24- inch VCT 8'-10'
24- inch VCT 10'- 12'
24- inch VCT 12' -14'
24- inch VCT 14'- 16'
24- inch VCT 16'- 18'
Bore 16- inch CI inc. hole
Bore 18- inch CI inc. hole
Bore 24- inch CI inc. hole
Bore under RR 24- inch CI
24- inch CI CI 150 0'-6'
TY "S" MH Dallas 414-D-7
Std MH 4- foot Dia. 6 feet deep
Extra Depth MH
For special MH at 91 + 00 and
101 + 59
Cut and plug existing sewers
Connect existing MH
Lower 1 2 - inch CI water
Cut and replace culvert floor
Cut and replace asphalt paving
Cut and replace concrete street
paving
Quantity
40 LF
10 LF
15 LF
35 LF
35 LF
10 LF
40 LF
1,800 LF
20 LF
95 LF
320 LF
485 LF
215 LF
3,415 LF
5 LF
25 LF
105 LF
3, 310 LF
1,035 LF
1,660 LF
965 LF
5 LF
10 LF
15 LF
10 LF
33 LF
85 LF
100 LF
85 LF
90 LF
30 LF
27 ea.
8 ea.
57 LF
30 CY
8 ea.
3 ea.
10 LF
160 SY
160 SY
160 SY
Unit Cost Total Cost
$4.75 $
4.75
4. 75
5. 10
5. 10
5. 10
5. 10
16. 75
16.75
19.85
19.85
19.85
19.85
19.30
19.30
19. 30
19. 30
20.85
20.85
23.80
23.80
23.80
23.80
23.80
23.80
23.80
36.00
40.00
47.00
93. 50
19.00
295.00
289.00
20.00
130.00
100.00
200.00
60.00
10.00
13.00
8.00
190.00
47. 50
71. 25
178. 50
178. 50
51.00
204.00
30, 150.00
335.00
1,885.75
6, 352.00
9,627. 25
4, 267. 75
65,909. 50
96. 50
482. 50
2,026. 50
69,013.50
21, 579.75
39, 508.00
22,967.00
119.00
238.00
357.00
238.00
785.40
3,060.00
4,000.00
3,995.00
8,415.00
570.00
7,965.00
2, 312.00
1, 140.00
3,900.00
800.00
600.00
600.00
1,600.00
2,080.00
1, 280.00
148
-------
TABLE XXXIII (Continued)
Item Description Quantity Unit Cost Total Cost
42 Cut and replace concrete . 140 SY $ 1.00 $ 140.00
sidewalk
43 Pea gravel embd. 30 CY 7.00 210.00
44 Granular Mtl. embd. 50 CY 2.00 100.00
45 2,000 psi encasement 2.830CY 13.50 38,205.00
46 Cone backfill excavation 3.220CY 11.50 37,030.00
rock grout
TOTAL $ 394,861. 15
actual injection of the material. Costs were not included for vehicles that
would be required since existing vehicles would be available in any water-
utility organization.
Equipment. It was determined that a portable injection system would
require one trailer for the injection equipment, including pump, hose, and
special manhole cover, and one trailer for the slurry tank. The estimated
cost of injection equipment, similar to that shown in Figure 66, is $6100,
and the estimated cost of the slurry mixing tank, Figure 65, is $ 1600. Also,
a modified pressure manhole cover, Figure 68, and water level recorder,
Figure 61, facilitate the injection process. The estimated cost of these
items are $300 and $200 each. Therefore, the total cost of the injection
equipment is about $8200. By using the same cost analysis methods used
in Table XXXIV, Table XXXV was tabulated. A 5. 7845 percent interest rate
and the estimated maintenance cost were used. Generally, the equipment
will require some maintenance after each field use and time for this work
has been included in the man hours of operation. Also, the equipment was
assumed to have an economic life of 12 years after which the pump, hoses,
and other parts will probably need replacement.
The total resulting cost per injection unit was determined to be
$13,983. 14 for an annual average cost of $ 1165. 26 over a 12-year period.
Polymer Cost. Calculations on the 15-inch diameter sewer indicate
that the capacity of the line just west of Shiloh Road (0.00326 slope) will
carry 3. 99 cubic feet per second when flowing just full. If the sewer was
overflowing at the upstream and downstream manholes, the flow capacity
would increase to 6. 59 cfs; however, the systems should carry 9. 6 million
gallons per day at this location when the total contributory area is com-
pletely developed. Therefore, for the polymer injection, it was assumed
that the 15-inch sewer would have to transport the full 9. 6 mgd (14. 8 cfs;
which is 2. 25 times the flow rate available when the upstream and down-
stream manholes are surcharged but not overflowing.
149
-------
TABLE XXXIV
KEEN BRANCH RELIEF SEWER COSTS
Year
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Annual
First
Cost
($)
14,085.98
14,085.98
14, 085.98
14,085.98
14, 085.98
14,085.98
14, 085.98
14, 085.98
14, 085.98
14, 085.98
14, 085.98
14, 085.98
14, 085.98
14,085.98
14, 085.98
14,085.98
14,085.98
14,085.98
14, 085.98
14, 085.98
14, 085.98
14, 085.98
14, 085.98
14, 085.98
14,085.98
14, 085.98
14,085.98
14, 085.98
14,085.98
14, 085.98
Interest
on
Bonds
($)
24,444.05
23,626.75
22, 814.45
21,999.64
21, 184.84
20, 370.04
19, 555.23
18,740.43
17, 925.63
17, 110.82
16, 296.02
15,481.22
14,666.41
13,851.61
13, 068.05
12,222.00
11,407.20
10,592.39
9,777.59
8,962.79
8,147.98
7, 333. 18
6, 518.38
5,703.57
4,888. 77
4, 073.97
3,259. 16
2,444.36
1,629.56
814.75
Estimated
Maintenance
And Operation
Cost
($)
0
70. 00
140. 00
210. 00
280. 00
350. 00
420. 00
490. 00
560. 00
630. 00
700. 00
770. 00
840. 00
910. 00
980.00
1, 050. 00
1, 120. 00
1, 190. 00
1,260. 00
1, 330. 00
1,400. 00
1,470. 00
1,610.00
1,680.00
1, 750. 00
1,820. 00
1,890. 00
1,960. 00
2,030. 00
2, 100.00
Total
Estimated
Annual
Expense
($)
38, 530. 03
37,782.73
37, 040.43
36,295.62
35, 550.82
34, 806.02
34, 061.21
33, 316.41
32, 571.61
31, 826.80
31, 082.00
30, 337.20
29,592.39
28,847.59
28, 134.03
27, 357.98
26, 613. 18
25,868.37
25, 123.57
24, 378.77
23, 633.96
22, 889. 16
22,214.36
21,469.55
20, 724.75
19,979.95
19, 235. 14
18,490. 34
17,745.54
17, 000.73
Total 422,578.51 365,710.84
31,010. 00
819,299.35
150
-------
TABLE XXXV
PORTABLE INJECTION PLANT COSTS
Year
1
2
3
4
5
6
7
8
9
10
11
12
Annual
First
Cost
($)
683. 33
683.33
683. 33
683.33
683.33
683.33
683. 33
683.33
683. 33
683.33
683.33
683.33
Interest
On
First Cost
($)
474.33
434.80
395. 27
355. 75
316. 22
276.69
237. 16
197.64
158. 11
118. 58
79.06
39. 53
Estimated
Maintenance
Cost
($)
100.00
125.00
150.00
175.00
200.00
225.00
250.00
275.00
300.00
300.00
300.00
300.00
Total
Estimated
Annual
Expense
($)
1, 257.66
1, 243. 13
1, 280.60
1, 214.08
1, 199.55
1. 185.02
1, 170.49
1, 155.97
1, 141.44
1, 101.91
1,062.39
1,022.90
Total 8,200.00
3,083.14
2,700.00
13,983. 14
During the spring of 1967, observations were made of the 15-inch
line, and it was determined that the line would overflow at one or more
points when the rainfall exceeded 2. 25 inches one day and 1. 19 inches the
following day. The observation manholes overflowed on the second day
for a four-hour period.
Table XXXVI shows the critical rainfall when sewer overflows would
likely have occurred for the years 1963 to 1966 (three full years). The rain-
fall data was taken at Dallas Love Field, which is approximately 15 miles
from the Garland bottleneck site. Local thunder showers may occur at Love
Field which do not occur at Garland; however, double mass curve studies
have shown that the long-range rainfall does not differ appreciably.
An estimate of the time of overflow on the line was made for each
of the storm periods, based upon the amount of rainfall and the.antecedent
time, which are shown in Table XXXVI.
151
-------
TABLE XXXVI
ESTIMATES OF POLYMER USE
Year
1963
1964
1965
1966
Month
April
March
May
Aug.
Sept.
Nov.
Feb.
May
Sept.
Feb.
April
Day
21
27
28
8
29
30
15
16
20
21
22
3
4
8
9
10
21
9
23
24
25
28
29
30
Estimated Volume
Number Time of of
Of Rainfall Overflow Flow
Storms (Inches) (Hours) (MG)
1
2
3
4
5
6
7
8
9
10
11
12
13
0.
1.
2.
1.
1.
0.
2.
0.
2.
3.
2.
1.
0.
1.
1.
4.
4.
2.
1.
1.
2.
3.
1.
1.
92
17
39
73
44
59
48
55
17
25
15
76
96
55
82
54
32
32
86
25
33
60
84
02
8
3
1
6
3
8
12
5
8
10
10
6
2
6
8
4
2
3.
1.
0.
2.
1.
3.
4.
2.
3.
4.
4.
2.
0.
2.
3.
1.
0.
200
200
400
400
200
200
800
000
200
000
000
400
800
400
200
600
800
WSR-301
Polymer Pounds
Dosage of
(Mg/1) Polymer
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
1,
1.
1,
2,
1,
1,
1,
1,
1,
1,
334.4
500.4
166.8
000.8
500.4
334.4
001.6
834.0
334.4
668.0
668.0
000.8
333.6
000.8
334.4
667. 2
333.6
Average Per Year 4. 33
2.400
50
1,000.8
The worst flow conditions would occur when the flow of 9. 6 mgd last-
ed for the entire overflew time period. By assuming this flow condition,
and the use of WSR-301 polymer slurry injected at a rate sufficient to pro-
vide 50 mg/1 polymer concentration, the quantity of polymer for all storm
overflows totaled 17,014 pounds. This volume of polymer was converted
into an annual average quantity by using the approximate average of 4. 25
storms per year (Table XXXVI). The annual average polymer use was calcu-
lated to be 4253 pounds. By using a unit cost of $0. 80 per pound, the
total cost for polymer would be $ 3402. 72 annually.
Since the slurry is only 30 percent by weight polymer, the costs of •
the nonsolvent and gelling agent must be included. The cost of isopropyl
152
-------
alcohol is $0. 69 per gallon or $0. 113 per pound. The gelling agent cost
$1. 30 per pound. By combining all material cost and based on a use of
4253 pounds of WSR-301, the annual cost of slurry is $4608. 35.
Labor Costs. An intense review of the practice used in the field
tests indicate that about 30 manhours were required to produce a batch of
polymer slurry. This time also included cleanup and any maintenance
during slurry production. At an hourly rate of $2. 87, the slurry production
cost would be approximately $366.
A review of the injection times in Table XXXVI shows that the aver-
age storm duration is 6. 0 hours. When the 4. 25 average number of storms
per year is used, the result is 25. 5 manhours per year for injection. By
again using the $2.87 hourly rate, the annual labor costs for two men is
$146. 37. Combining all labor costs, a total of $658. 66 annually is ob-
tained.
When the annual average mobile injection plant and equipment cost
of $1165. 26 is combined with the annual estimated material cost of $4608. 35
and the estimated labor cost of $658. 66, the annual average cost of in-
jecting WSR-301 to control flow in the existing 15-inch diameter Keen Branch
Sewer is $6432. 27. Although certain fixed expenses such as vehicle opera-
tion and general administrational costs were not included, the polymer cost
was only one-fourth the annual average cost of building the relief sewer.
It should be emphasized that one injection system was used in the above
calculations. However, probably two injection units would be necessary
on occasions. Therefore, the equipment cost would be twice that in-
dicated with a slight increase in slurry material cost. If a city antici-
pated using this technique for flow control, additional units could be
purchased based on the actual operating performance of an initial single
unit.
Finally it must be pointed out that the indirect benefits of both
systems were not evaluated because of the difficulty involved in such an
analysis.
In summary, the cost analysis based on construction of a relief
sewer line resulted in an average cost of $27, 310 per year. The cost
analysis based upon the use of portable injection equipment and a polymer
slurry during peak flow periods was $6432 per year.
153
-------
BIBLIOGRAPHY
(1) Sullivan, R.H., "Problem of Combined Sewer Facilities
and Overflows. " Tournal WPCFr 41, 113 (1969).
(2) Standard Methods for Examination of Water and Wastewater.
12th Ed., Amer.'Pub. Health Assn., New York (1965).
(3) Maloney, I.E. , "Detergent Phosphorus Effect on Algae, "
Tournal WPCF. 38 (1966).
(4) Hardenbergh, W.A., Rodie, Edward R., Water Supply and
Waste Disposal. International Textbook Company, Scranton, Pennsylvania,
pp. 318-349, 372-395 (1961).
(5) Clark, John W., Viessman, Warren, Jr., Water Supply and
Pollution Control. International Textbook Company, Scranton,
Pennsylvania, pp. 258-317 (1966).
(6) Woldman, Michael L., "Effects of Selected Organic Poly-
electrolytes on Biological System, " Masters Thesis at Oklahoma State
University in the Department of Environmental Engineering (May, 1967).
(7) Simpson, G.D., Curtis, L.W., "Treatment of Combined
Sewer Overflows and Surfacewaters at Cleveland, Ohio," Tournal WPCF.
41, 151 (1969).
(8) Burm, R.J., Krawczyk, D.F., Harlow, G.L., "Chemical
and Physical Comparison of Combined and Separate Sewer Discharges,"
Tournal WPCF. 40, 112 (1968).
(9) Burm, R.J., "The Bacteriological Effects of Combined Sewer
Overflows on the'Detroit River," Tournal WPCF. 39, 410 (1967).
(10) Evans et al, "Treatment of Urban Stormwater Runoff,"
Tournal WPCF. 40, R162 (1968).
155
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APPENDICES
Appendix A - Fluid Friction Reducing Polymers
Literature Survey
Appendix B - Discussion of Fluid Modification by
Polymers
Appendix C - Derivation of Graphs of Percent Flow
Increase vs Polymer Concentration
Appendix D - Polymer Slurry Mixing Techniques
157
-------
APPENDIX A
FLUID FRICTION REDUCING POLYMERS
LITERATURE SURVEY
Western Company Reports
1. Pruitt, G. T.; Crawford, H.R., "A Study of the Mixing of Drag
Reduction Polymers," Final Report, Contract No. N123(60530)34461A,
Naval Ordnance Test Station, Pasadena, California, October, 1964.
2. Crawford, H.R.; Pruitt, G.T., "Drag Reduction of Dilute Polymer
Solutions," Symposium on Non-Newtonian Fluid Mechanics I, 56th
Annual Meeting A.I.Ch.E. , Houston, Texas, December 1-5, 1963.
3. Pruitt, G.T.; Crawford, H.R., "Effect of Molecular Weight and
Segmental Constitution on the Drag Reduction of Water Soluble Polymers, "
Report No. DTMB No. 1, Contract No. Nonr-4306(00), David Taylor Model
Basin, Washington, D.C., April, 1965.
4. Pruitt, G.T.; Rosen, B.; Crawford, H.R., "Effect of Polymer Coiling
on Drag Reduction," Report No. DTMB No. 2, Contract No. Nonr-4306(00),
David Taylor Model Basin, Washington, D. C., August, 1966.
5 Crawford H.R. "Method of Reducing Hydrodynamic Drag on Objects
Moving Through Water," U .S . Patent No. 3 ,230, 919 . Filed 1961(1966).
6. Pruitt, G.T.; Crawford, H.R., "Drag Reduction Rheology and Capillary
End Effects of Some Dilute Polymer Solutions, " Final Report,
Contract No. 60530-8250, U.S. Naval Ordnance Test Station, Pasadena,
California, June, 1963.
Supplier Bulletins
7 Properties and Uses: Cellulose Gum. Hercules Powder Company,
Cellulose and Protein Products Department, Wilmington, Delaware.
8 Pol vox Friction Reducing Agents FRA. Applications Bulletin F-41350,
Union Carbide Corporation, Chemical Division, 270 Park Avenue, New
York, New York 10017, March, 1966.
9 GaflocRC-61 Technical Bulletin 454-66, General Aniline and Film
Corporation, 140 West 51st St. , New York, New York 10020.
10. TAGUAR. Stein, Hall and Company, Inc., 285 Madison Avenue,
New York, New York, 1959.
159
-------
11. Polvox Water - Soluble Resins, Union Carbide Corporation, Chemicals
Division, 270 Park Avenue, New York, New York 10017, 1958 and 1962.
12. Gantrez AN169 Poly(methyl Vinyl ether/maleic anhydride), General
Aniline and Film Corporation, 140 West 51st St., New York, New York,
1961.
13. Separan. The Dow Chemical Company, Midland, Michigan, 1961.
14. Powell, G. M.,III; Bailey, F.E., Jr., Poly (Ethvlene Oxide) Resins.
High Molecular Weight Polymers of Ethvlene Oxide. Research Department,
Union Carbide Chemicals Company, Division of Union Carbide Corporation,
270 Park Avenue, New York, New York 10017.
Chemical Abstracts
15. Kozmina, O.P.; Kurlyankina, V.I.; Molotkov, V.A.; Slavetskaya,
P.A., Vvsokomolekul Soedin. 7_(6) 958-61 (1965).
16. Kimball, G.E.; Cutler, M.; Samelson, H., T. Phvs. Chem. . 56,
57 (1952).
17. Harris, F.E.; Rice, S.A.. T. Phvs. Chem. . 58, 725, (1954).
18. Rice, S.A., Rev. Mod. Phys.. 31 (1), 69, (1959).
19. Hoppler, Chem. Ztg.. 66, 132 (1942); Kolloid Z. 98, 348 (1942).
20. Fox, T.G., Jr.; Fox, J.C.; Flory, P.J., T. Am. Ghem. Soc. 73, 1901
(1951)
21. Alsherman, F.; Pals, D.T.F.; Herman, J.J., Recueil Trav. Chem.
Pavs. - Bas.. 71 (1952) 56.
22. Ripkin, J.F.; Pilch, M., N.A.S. Accession No. N65-19091, Rpt. No.
AD 6105 12, 1964.
23. Tschoegl, N.W., T. Chem. Phvs. . 40_(2), 473, (1964).
24. Williams, M.C., Univ. Microfilm, order No. 64-10, 333;
Dissertation Abstr. 2^(4), 2407-8 (1964).
25. Adams, F. B.; Whitehead, J.C.; Bogue, D.C.. A.I.Ch.E. Tournal.
li(6), 1026 (1965).
26. Astaritaf G.r Ind. End. Chem. Fundamentals. 4 (3). 354 (1965).
27. Fox. T.G.. T. Polvmer Sci. . Pt. C.. No. 9. 35-42 (1965).
28. Astarita, G.; Nicodemo, L., Ind. Enq.Chem. Fundamentals. 5.(2),
237 (1966).
160
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29. Barlow, A.J.; Subramanian, Brit. T. Appl. Phv. . 17_(9), 1201-14
(1966).
30. Gadd, G.E., Chem. Engr.. 17(2), 46-50 (1966).
31. Hoyt, J.W., T. Polymer Sci. . P & B, 1(10), 713-16 (1966).
32. Lanaer H.. Kolloid-Z. Z. Polymer. 209(1). 26-33 (1966).
33. Geller, B.E., Vvsokomolekul Soedin. .5(11), 1696-701 (1963).
34. Lange, H., Koiloid-Z. 19_9 (2), 128-35 (1964).
35.. Sheehan, C.J.; Bisio, A.L., Rubber Chem. Technol. . 39 (1),
149-92 (1966).
36. Lodge, A.S., Scuola Azione. No. 3, 59-84 (1965).
37. Mirandaf T.T.. Qffic . Dig.. T. Paint Tec hnol. Eng. . 37(498).
62-96 (1965).
38. Rohm and Hass, Co., Brit. 1,009,004 (Cl. C 08f.) Nov. 3, 1965;
U.S. Appl. Sept. 7, 1961.
39 Kadyrov, N.; Mirsalimov, A.; Aripov, E.; Akhmedov, K., Uzbeksk.
Khim. Zh.. 8(6), 55-60 (1964).
40. Saureur, C., Ann. Phvs.. 1(506), 271-96 (1964).
41. Shibayama, K.; Tanaka, T., Kobunahi Kaqaku. 21(235), 690-3 (1964)
42. Goppel, J.M., Hhem. Weekblad. 61(1), 13-20 (1965).
43. Hermans, J.J., T. Polvmer Sci. . Ft. C No. 12, 51-62 (1966).
44. Miller, I.F.; Bernstein, F.; Gregor, H.P., T. Chem. Phys. , 43_(5),
1783-9 (1965).
45. Conway, B.E.; Desnoyers, J.E.; Smith, AC., Phi. Trans. Roy.
Snr. London Ger. A. 251(1074), 389-437 (1964).
46. Borchert, O., MfitalLoberflacche. 11(10), 310-12 (1965).
47. Christman, R.F., T. Water Pollution Control Federation, 3_8(5),
685-96 (1966).
48. Sridhar, ™ if r.. T. Sr.i. Ind. Res .. 25(4) 167-71 (1966).
49. Weiner, O.J., T- Water Pollution Control Federation. 18(5), 728-33
(1966).
161
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50. Braun, R., Schweiz Z. Hvdrol.. 2l6.(2), 601-27 (1964).
51. Mancy, K.H.. T. Water Pollution Control Federation. 18(5) / 696-9
(1966).
52. Knowles, D.J., Nucl. Safety. 1(1), 52-6 (1965).
53. Selleck, R.E., T. Water Pollution Control Federation. 18(5), 714-23
(1966).
54. Kuznetsova, L.P., Energetick. L4(4), 14-16 (1966).
55. Kohn, P.G., Svmp. Soc. Exptl. Biol.. 19. 3-17 (1965).
56. Marten, J.F., Effluent Water Treat. T.. 5.(12), 617-19 (1965).
57. Burbank, N.C., Jr., Air. Water Pollution. 1.0(5), 327-42 (1966).
58. Collins, R.P., Am. Water Work Assoc. . 5_8(6), 715-19 (1966).
59. Goodman, B.L., Water Wastes Ena. . 3_(7), 68-70 (1966).
60. Chem. Ena. News. 44(42), 40-1 (1966).
61. Toler, L.G.; Cherry, R.N., U. S. Geoi. Surv. . Water Supply
Paper No. 1822. 63-5 (1966).
62. Luskina, B.M.. Gay. Khromatoa. Sb. . Moscow. 1(3) 89-93 (1965).
63. Bramer, H.C., Water Sewage Works . 113(8) 275-8 (1966).
162
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APPENDIX B
DISCUSSION OF FLUID MODIFICATION BY POLYMERS
The chemical and physical changes that polymers impart to fluids
to provide viscous friction reduction cannot be fully explained. Currently,
the change in flow phenomena that occurs when polymers, such as those
selected for investigation in this program, are added to fluids is under
intensive research by a number of investigators as indicated in Reference
1. Basically, previous studies have determined that polymers probably
tend to act as "turbulence dampers" and, in effect, damp out the very
irregular paths of the fluid particles near the wall and extend the laminar
boundary layer further into the turbulent flow core. This damping effect
causes the laminar sublayer to increase in thickness, resulting in a re-
duction in the wall velocity gradient and shear stress gradient which pro-
vides a reduction in the frictional resistance to flow, since the action of
wall shear stress is to slow down the fluid near the wall.
Although this explanation makes the process of friction reduction
by polymers appear less complicated, it has so far defied complete expla-
nation. Some of the more obvious peculiarities of friction reduction result-
ing from using polymers are briefly discussed below.
The Critical Shear Stress. The shear stress at which a transition
from ordinary turbulent flow to friction-reduced turbulent flow occurs, ap-
pears to have to be surpassed before the friction-reducing phenomena will
take place; therefore, the Reynolds number must be in the turbulent region.
The So Called "Diameter Effect. " A polymer of the same concentra-
tion will exhibit different levels of friction reduction in different sizes of
pipe.
The "Shear Degradation of Polymer Effect. " Some of the most ef-
fective friction-reducing polymers are found to be adversely affected by
high shear environments such as imparted by some types of pumps.
Basic Characteristics of Polymer Friction Reduction
How polymers affect a fluid can be better understood by studying
an actual flow curve such as that shown in Figure Bla and b. These graphs,
taken from Reference 2, show actual pressure drops or frictional losses for
water with various concentrations of Polyox Coagulant-701 in a 0.416-inch
diameter pipe. The higher polymer concentrations tend to increase the vis-
cosity (the fluid property that causes shear stress in a moving fluid since,
without viscosity, there is no fluid resistance). As a result, a moderate
increase in pressure drop in the laminar flow regime occurs as is shown
in Figure Bla. It should be observed that the 2 and 10 mg/1 polymer con-
centrations do not cause friction reduction immediately after transition
from laminar to turbulent flow. This polymer solution characteristic occurs
163
-------
10
9 -
8 -
-
6
1
o
o
_ 9
(O e
UJ
K
3 3
V)
tfi
UJ
I I I I I
K 0
O 7
C 6
.01
BASE LINE FOR WATER
O 2 WPPM IN TAP WATER
A 10 WPPM IN TAP WATER
X 50 WPPM IN TAP WATER
• 250 WPPM IN TAP WATER
' I I I I I
I I I I I I
' ' 1 I I I I
3 4 56789 10
.Ot
3 4 98789 0.1
4 5 6789)
VELOCITY, FT./SEC
Figure Bla. Flow Studies in 0.416 Inch I.D. Tubing
Tap Water With Indicated Concentrations
of Polyox WSR-701.
164
-------
1000
o
1—I—I I I 1 I
to
0.
UJ
cz
en
oo
ui
tr
CL
9
H •
O
,
BASE LINE FOR WATER
O 2 WPPM IN TAP WATER
A 10 WPPM IN TAP WATER
X 50 WPPM IN TAP WATER -
• 250 WPPM IN TAP WATER
5 6 7 8 9 |0
56789 |QO
56789
VELOCITY, FT./SEC.
Figure Bib. Flow Studies in 0.416 Inch I.D. Tubing
Tap Water With Indicated Concentrations
of Polyox WSR-701.
165
-------
because these solutions reach their critical shear stresses well after the
flow has transitioned into the turbulent region.
In Figure Bib, it is seen that all polymer concentrations are exhib-
iting some friction reduction, although the 50 and 250 mg/1 concentrations
generally provide identical friction reduction (the 50 mg/1) concentration
is near the optimum concentration for friction reduction in this size pipe
and at these velocities; the 250 mg/1 solution is unnecessarily high for
maximum obtainable friction reduction in this flow system).
The shear degradation phenomenon is also illustrated in Figure
Bib, by the 10 mg/1 solution at flow velocities above 15 feet per second.
This degradation was caused by the shear in the flow system pump, not by
the shear stress in the pipe. On the other hand, the solution with 50 mg/1
polymer concentration is unaffected at velocities up to 38 feet per second.
Thus, it is apparent that the concentration of sensitive polymers (such as
Polyox Coagulant-701 and WSR-301) must be increased above that normally
required for optimum friction reduction if passage through a pump prior
to entering a conveyance system will occur. In this way, enough of the
polymer will survive the high shear environment to give the desired friction
reduction. Unfortunately, the additional amount of polymer required to
survive this high shear environment cannot presently be predicted and must
be determined experimentally.
Flow Control by Using Polymers
The ways in which some polymers can be used to improve and con-
trol the flow performance of fluids in conduits are illustrated in Figure B2.
In this figure, laminar and turbulent flow curves are illustrated for water
and for water with an optimum concentration of polymer. In the laminar
region, the water with additive will generally exhibit a slight increase in
frictional losses because of the additive's viscosity effect on the fluid.
In the turbulent region, the optimum polymer concentration will cause fric-
tional losses to be reduced by 80 to 85 percent (Reference B). This per-
cent friction reduction is limited by the extrapolated laminar flow line,
since the minimum friction loss possible is that exhibited by laminar flow.
The types of flow performance changes which can be effected by
using polymers to modify fluids are illustrated by the lines A-B, A-C, and
A-D in Figure B2. One common way of expressing the flow performance
obtained is percent friction reduction. Percent friction reduction, illus-
trated by line A-B, is defined at a constant flow rate by the ratio of fric-
tional loss or pressure difference at points A, B, and B1. By using such
data points, the percent friction reduction can be calculated by the
equation
166
-------
CO
CO
o
UJ
cr
CO
O
cc
u.
UJ
UJ
Q.
CD
O
WATER
WATER WITH OPTIMUM
FRICTION REDUCTION
ADDITIVE CONCENTRATION
LAMINAR
FLOW
EXTRAPOLATED
LAMINAR FLOW
LINE
TURBULENT
FLOW
LOG (FLOW RATE)
Figure B2. Examples of Flow Modification of Water by
Polymers.
167
-------
The constant flow rate friction reduction indicates that the frictional
losses within a fluid (in turbulent flow) can be reduced up to 85 percent by
using optimum polymer concentration.
Another common method of expressing flow performance is by per-
cent flow increase, as illustrated by line A-C. These points illustrate
that the flow rate can be increased (by maintaining a constant energy level
to obviate the friction losses or pressure drop along a pipe system) up to
140 percent by using an optimum concentration of polymer in the fluid
(Reference 1). This flow increase is defined as percent flow increase, or
A better understanding of how polymers can affect a gravity flow
system can be obtained by considering the following flow system. Assume
a gravity flow system with two long, large-diameter sections joined by a
section of moderate length but of smaller diameter. During peak flow con-
ditions, the small diameter pipe's capacity is inadequate to carry the flow,
causing a surcharge or static head to build up in the upstream section (Fig-
ure B3a). The total friction loss head, HI, is equal to the sum of the fric-
tion losses in each section of the line, H2 and H3. The head losses due to
frictional resistance to flow in the small-diameter section is assumed to
be sufficient to overflow the upstream section.
By injecting an adequate concentration of polymer upstream from the
restricted section, the maximum obtainable frictional loss reduction could
be obtained if the flow remained constant; however, the friction reduction
obtained in the downstream restricted section and large diameter section
will cause the total frictional head to be reduced to hi! (see Figure B3b).
This reduction in frictional resistance to flow will cause the flow rate to
stabilize at a somewhat higher rate; i. e. , the flow adjusts itself from
point A to point D as in Figure B2. This point indicates that both a head
drop and a flow increase occurred to obtain a new equilibrium flow con-
dition.
REFERENCES
1. "Proceedings of the Symposium of Viscous Drag Reduction," Sept. 24
and 25, 1968, Plenum Press, 1969.
2. Pruitt, G. T. and Crawford, H. R. , "Effect of Molecular Weight and
Segmental Constitution on the Drag Reduction of Water Soluble Poly-
mers, Report No. DTMB-1, " prepared for David Taylor Model Basin,
Hydromechanical Laboratory, Contract No. NOnr-4306(OD), April, 1965.
3. Whitsitt, N.F. , Harrington, L.J. , and Crawford, H. R. , "Effects of
Wall Shear Stress on Drag Reduction of Visioelastic Fluids, Report No.
DTMB-3, " prepared for Naval Ship System Command, ONR, Contract
No. NOnr-4306 (W), June, 1968.
168
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Flood Level
a.
Flood Level
:. .
Figure B3. Friction Head Reduction Effects
Obtained by Using Polymers.
169
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APPENDIX C
DERIVATION OF GRAPHS OF
PERCENT FLOW INCREASE VS POLYMER CONCENTRATION
A discussion of how polymers can modify such fluids as water and
wastewater is presented in Appendix B, where it is shown that flow per-
formance can be expressed as 1) percent friction reduction, at a constant
flow rate, or 2) percent flow increase at a constant energy or static head
level, or 3) a combination of both flow increase and friction reduction, as
in the case of gravity flow systems. Also, this discussion explained that
polymers affect fluids by decreasing turbulent flow losses. Therefore, by
maintaining a constant flow rate, a reduction in the head required to over-
come frictional losses will occur; however, if a constant energy level is
maintained, the flow can be increased until frictional losses again equal
the energy level available to drive the fluid.
In the six-inch flow tests conducted during this program, almost
constant water and sewage flow rates were maintained both before and dur-
ing polymer injection; however, during the period polymer was injected, a
slight increase in flow rate occurred due to the addition of the highly con-
centrated polymer solutions. To obtain a polymer concentration of 200 mg/1
in a sewage flow rate of 550 gpm, the necessary injection rate for Polyox
Coagulant-701 and WSR-301 slurries was 23 gpm, resulting in a total flow
rate of 573 gpm.
Similar slight flow increases were imposed on the 350 and 450 gpm
flow rates for 50 mg/1 and 100 mg/1, as shown in Figures Cl through C6.
These figures show the measured pressure or friction drop obtained for the
three flow rates in the 30-foot test length of six-inch diameter pipe.
During each test, the pressure drop for turbulent flow was measured
at each of the three flow rates. A polymer solution was then added and the
pressure drop again determined after steady flow was again obtained at each
flow rate. These data points are shown for water and sewage at 73°F in the
above figures. Similar graphs were prepared from data points for each poly-
mer tested.
To determine each polymer's effectiveness as a reducer of frictional
losses, the percent flow increase was determined from graphs (similar to
those shown in Figures Cl through C6) of various polymer concentrations
(Table XVII presents the test data matrix).
Figure C7 illustrates how the percent flow increase was derived
from the graphs of flow rate versus pressure drop. To avoid extrapolating
beyond the limits of the data obtained, 250 and 300 gpm were selected for
calculating the flow increase.
The flow versus pressure drop graphs were entered at 300 gpm, and
the maximum pressure drop was determined for this flow rate (the value at
170
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;
2
IIZ
It!
8
3
50 ppm
x 100 ppm
/200ppm
\
CL
o
oE
LU
a:
CO
7
,
z
•t
'200 30O 4OO 500
FLOW RATE -00/77
Figure Cl. Polyox Coagulant-701 in Six-Inch Test
Facility at 73°F in Water.
171
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200
300
700 800 900
400 500 600
FLOW RATE- gpm
Figure C2. Polyox Coagulant-701 in Six-Inch Test Facility at 73°F
in Sewage (3 ml/1 Settleable Solids).
172
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200
300
400 500 600
FLOW RATE - gpm
700 8OO 9OO
Figure C3. Polyox Coagulant-701 in Six-Inch Test Facility at 73°F
in Sewage (9 ml/1 Settleable Solids).
173
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PRESSURE DROP— INCHES of WATER for 3O.I FEET
io — ro w * 01 o> ^i OB «> c
J
/
J
/
/
7
z
/ i
y/
s*^
/
/
X
X
«./
f
1
v
a/
X
i
/
/
/
/
7 1
/
i|*
rf*
„/
J
/
pprr
yl
/
f
00 i
,20
)pm
0 p
sm
200 3OO 4OO 5OO 60O 700 800 9OO
FLOW RATE-
Figure C4. WSR-301 in Six-Inch Test Facility at 70°F in Water.
174
-------
:
200
300 4OO 5OO 600
FLOW RATE — gpm
700 800 900
Figure C5. WSR-301 in Six-Inch Test Facility at 70°F
in Sewage (3 mg/1 Settleable Solids).
175
-------
200
300 4OO 5OO 60O TOO BOO
FLOW RATE- gpm
900
Figure C6. WSR-301 In Six-Inch Test Facility at 70°F
in Sewage (9 mg/1 Settleable Solids).
176
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WATER/SEWAGE
CONSTANT
PRESSURE
DROP
FLOW RATE
PRIOR TO
INJECTING
POLYMER -
30O
LOG (FLOW RATE,#*?7)
Figure C7. Example of Use of Flow Data to Derive
Percent Flow Increase.
177
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the intersection of 300 gpm and the turbulent water or sewage flow line).
At this pressure drop or energy level, a horizontal line was projected to
each of the curves obtained for the various polymer concentration. At the
intersection of this projected line and the curves, vertical lines were pro-
jected back to the abscissa to determine the flow rate. The percent flow
increase was then calculated by the formula
*100f
.nn
300 gpm
where Qc is the flow rate in gpm for polymer concentration c. This same
procedure and similar calculation was made for a 250 gpm flow rate for
each of the selected polymers.
178
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APPENDIX D
POLYMER SLURRY MIXING TECHNIQUES
Rapid dispersion is required to quickly and completely dissolve
water-soluble polymer particles in aqueous solutions. The polymer slurry,
when fed into an extreme turbulent regime as occurs in the throat of an
eductor, was found to be an efficient method of obtaining polymer disper-
sion without conducting an extensive investigation into numerous mechan-
ical systems. It was found that the majority of polymers used during the
six-inch model sewer line testing program could not be rapidly dispersed
in aqueous solutions when the polymer was added in a dry state. Massive
agglomerations occurred and lengthy hydration times were required when
this technique was used.
It was determined, however, that if polymers were suspended in
a slurry and introduced into an aqueous solution by the high turbulence of
an eductor, the hydration time was greatly reduced. In sewer lines where
flow turbulence was present, the total hydration time or solvation process,
using the eductor, was reduced to a few minutes.
The process of preparing the slurry involved three major steps: 1)
the nonsolvent (isopropyl alcohol) and the gelling agent (klucel H) were
mixed thoroughly; 2) the nonsolvent and the gelling agent were allowed to
gel; and 3) the water-soluble polymer was added to the gel to complete the
slurry. It was important that two precautions be taken during the slurry
making process: 1) the gelling agent had to be added carefully to the non-
solvent so that lumps would not form (lumping or agglomeration of the gel-
ling agent in the nonsolvent resulted in much longer gelling times, so a
standard number 5 mesh sieve was used to eliminate lumps); and 2) the
polymer powder had to be added slowly to insure a more homogeneous
slurry.
Initially, only very small volumes of slurry were needed for the
six-inch model testing phase of the program. These small volumes did
not incur mixing problems, and it was assumed that the same mechanical
mixing technique could be applied to larger slurry productions. The prin-
ciple of using a positive-displacement gear pump as a slurry blending-
mixing device was initially used on the 24-inch sewer line tests. The
nonsolvent was pumped into the portable slurry tank and the klucel H
added. Recirculation and blending were accomplished by using a two-inch
positive-displacement gear pump driven by a variable-speed electric motor.
The polymer was added to the gel by throttling the recirculation flow while
maintaining a constant pump speed, creating a slight vacuum on the suction
side of the pump. This vacuum was used to carry the polymers into the gel.
The gelled slurry was withdrawn from the bottom of the tank and recirculated
back into the top of the tank, which was open to the atmosphere.
179
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This technique proved successful only for slurry volumes of less
than 300 gallons. Between 300 and 500 gallons, it became increasingly
difficult to achieve a good homogeneous slurry. Above 500-gallon slurry
quantities, additional mixing devices were required to obtain a gel. The
polymer powder that did not disperse into the gel before reaching the tank
tended to adhere to other moistened polymer already in the tank, forming
a massive lump of moistened polymer. As a result, the gel would flow
around this mass and not mix with the polymer. To avoid this, the slurry
tank was equipped with a two-horsepower mixer to provide thorough
mixing of the polymer and gel. By using this additional mixing device,
500-gallon batches were gelled in about 12 hours.
Due to the problems encountered, a modified mixing technique
was investigated which proved to be effective. The nonsolvent was
gelled in two 400-gallon tanks equipped with 1/3-horsepower mixers
operated continuously as the gelling agent was added to the nonsolvent.
This procedure reduced the total gelling time and provided a better
quality gel. After six to eight hours, a homogeneous gel was obtained
and transferred into the portable slurry tank unit of the injector. Polymer
was then slowly added to the gel, using the method described previously,
but maintaining constant agitation of the gel as the polymer was added.
The most efficient method of using polymers in a fluid would be
by adding the polymers in a dry state; however, additional work and research
will be necessary to perfect and adapt such a method for use in making
large slurry batches.
180
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r,
BIBLIOGRAPHIC: The Western Company of North America. Polymers
For Sewer Overflow Control FWPCA Publication No. WP-ZO-22,
1969.
ABSTRACT: Six water-soluble polymers were investigated to deter-
mine their effects upon aquatic flora and fauna, flow character-
istics of wastewater, and the operation of a wastewater treat-
ment plant. It was found that the polymers and gels, in magni-
tudes tested, were not toxic to bacteria, algae, or fish, and did
not act as a nutrient for algae growth. Based upon calculations
obtained from flow test data, a maximum flow increase of 2.4
times the flow prior to injection could be obtained if a constant
head was maintained. Laboratory flow test data indicated that
if flow rates were held almost constant prior to and during poly-
mer injection, a reduction in the static head occurred as a result
of friction reduction within the fluid. The most effective polymers
in providing energy reduction were Polyox Coagulant-70 1, WSR-
301, andAP-30; however, AP-30 required higher polymer con-
centrations to obtain equivalent flow characteristics. In field
tests on a 24-inch diameter line, it was found that polymer con-
centrations of between 35 and 100 mg/1, decreased frictional flow
resistance sufficiently to eliminate surcharges of more than six
feet. Based upon an economic analysis, the average annual cost
of new construction was approximately five times the cost of us-
ing polymers during peak storm-flow periods.
ACCESSION NO:
KEYWORDS:
Polymers
Overflow Control
Friction Reduction
Infiltration
Economic Analysis
Toxicity Test
Sewer Lines
BIBLIOGRAPHIC: The Western Company of North America. Polymers
For Sewer Overflow Control FWPCA Publication No. WP-ZO-22,
1969.
ABSTRACT: Six water-soluble polymers were investigated to deter-
mine their effects upon aquatic flora and fauna, flow character-
istics of wastewater, and the operation of a wastewater treat-
ment plant. It was found that the polymers and gels, in magni-
tudes tested, were not toxic to bacteria, algae, or fish, and did
not act as a nutrient for algae growth. Based upon calculations
obtained from flow test data, a maximum flow increase of 2.4
times the flow prior to injection could be obtained if a constant
head was maintained. Laboratory flow test data indicated that
if flow rates were held almost constant prior to and during poly-
mer injection, a reduction in the static head occurred as a result
of friction reduction within the fluid. The most effective polymers
in providing energy reduction were Polyox Coagulant-70 1, WSR-
301, andAP-30; however, AP-30 required higher polymer con-
centrations to obtain equivalent flow characteristics. In field
tests on a 24-inch diameter line, it was found that polymer con-
centrations of between 35 and 100 mg/1, decreased frictional flow
resistance sufficiently to eliminate surcharges of more than six
feet. Based upon an economic analysis, the average annual cost
of new construction was approximately five times the cost of us-
ing polymers during peak storm-flow periods.
BIBLIOGRAPHIC: The Western Company of North America. Polymers
For Sewer Overflow Control FWPCA Publication No. WP-20-22,
1969.
ABSTRACT: Six water-soluble polymers were investigated to deter-
mine their effects upon aquatic flora and fauna, flow character-
istics of wastewater, and the operation of a wastewater treat-
ment plant. It was found that the polymers and gels, in magni-
tudes tested, were not toxic to bacteria, algae, or fish, and did
not act as a nutrient for algae growth. Based upon calculations
obtained from flow test data, a maximum flow increase of 2.4
times the flow prior to injection could be obtained if a constant
head was maintained. Laboratory flow test data indicated that
if flow rates were held almost constant prior to and during poly-
mer Injection, a reduction in the static head occurred as a result
of friction reduction within the fluid. The most effective polymers
in providing energy reduction were Polyox Coagulant-70 1, WSR-
301, andAP-30; however, AP-30 required higher polymer con-
centrations to obtain equivalent flow characteristics. In field
tests on a Z4-inch diameter line, it was found that polymer con-
centrations of between 35 and 100 mg/1, decreased frictional flow
resistance sufficiently to eliminate surcharges of more than six
feet. Based upon an economic analysis, the average annual cost
of new construction was approximately five times the cost of us-
ing polymers during peak storm-flow periods.
ACCESSION NO:
KEY WORDS:
Polymers
Overflow Control
Friction Reduction
Infiltration
Economic Analysis
Toxicity Test
Sewer Lines
ACCESSION NO:
KEY WORDS:
Polymers
Overflow Control
Friction Reduction
Infiltration
Economic Analysis
Toxicity Test
Sewer Lines
_J
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