TECHNICAL NOTE
ORP/TAD-76-1
DETERMINATION OF RADIUM
REMOVAL EFFICIENCIES IN IOWA
WATER SUPPLY TREATMENT
PROCESSES
33
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4
UJ
CD
THE UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RADIATION PROGRAMS
JUNE 1976
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Technical Note
ORP/TAD-76-1
Determination of Radium Removal Efficiencies in Iowa
Water Supply Treatment Processes
by
R. J. Schliekelman, P.E.
Iowa Department of Environmental Quality
Des Moines, Iowa 50316
April 1976
Contract No. 68-03-0491
Project Officer
William L. Brinck
Radiochemistry and Nuclear Engineering Facility
U.S. Environmental Protection Agency
Cincinnati, Ohio
Prepared for
U.S. Environmental Protection Agency
Office of Radiation Programs
Washington, D.C. 20460
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EPA Review Notice
This report has been reviewed by the EPA and
approved for publication. Approval does not
signify that the contents necessarily reflect
the views and policies of the EPA, nor does
mention of trade names or commercial products
constitute endorsement or recommendation for
use.
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PREFACE
The Office of Radiation Programs of the U.S. Environmental
Protection Agency carries out a national program designed to evaluate
population exposure to ionizing and non-ionizing radiation, and to
promote development of controls necessary to protect the public health
and safety. This report was prepared in order to determine the natural
radioactivity source terms associated with radium in water supplies
and the radium removal efficiencies in water treatment processes.
Readers of this report are encouraged to inform the Office of Radiation
Programs of any omissions or errors. Comments or requests for further
information are also invited.
David S. Smith
Director
Technology Assessment Division (AW-459)
Office of Radiation Programs
m
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ABSTRACT
The purpose of the study was to sample and analyze waters from nine municipal
water treatment plants in the State of Iowa to determine the efficiency of
radium-226 removal in a variety of treatment processes and to provide cost
data for these processes. Supplies with a high naturally occurring radium
content over 5 pCi/1 in Jordan and Dakota sandstone formation well waters were
selected and included four different treatment processes: reverse osmosis,
iron removal filtration, sodium ion exchange, and lime-soda ash softening.
Analyses were performed to determine radium, hardness, and other parameters on
the well water and removals of these parameters through the treatment process.
Radium-226 removals through the reverse osmosis, sodium ion exchange, and
lime-soda ash softening plants were in the range of 95% removal. The hardness
removals with reverse osmosis and ion exchange processes were generally nearly
identical to the radium removal. The shortage of soda ash during the course
of the study caused considerable variation in hardness and radium removals in
the lime-soda ash softening process, but generally, the radium removals were
greater than the hardness and iron removals. Radium removals in the iron
removal plants ranged from 12 to 38%.
Total annual capital and operation costs and plant operation and maintenance
costs are included but were highly variable and typical cost data could not
be developed.
This report was submitted in fulfillment of Contract No. 68-03-0491 by the
Iowa Department of Environmental Quality under sponsorship of the Environ-
mental Protection Agency. Work was completed as of June 4, 1975.
IV
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CONTENTS
Section Page
No. No.
1. Summary and Conclusions 1
2. Recommendations 8
3. Introduction 9
4. Objectives 10
5. Study and Sampling Procedures 11
6. Radioactivity Studies in Iowa Water Supplies 16
7. Water Mineralization and Health 19
8. Hydrogeology 21
9. Water Treatment Plant Wastes 29
10. Reverse Osmosis Desalting 33
10.1 Process Description
10.2 Greenfield, Iowa
11. Aeration and Iron Removal 46
11.1 Process Description
11.2 Adair, Iowa - Greensand Filter
11.3 Stuart, Iowa - Iron Removal Filter
12. Sodium Cation Exchange Softening 64
12.1 Process Description
12.2 Eldon, Iowa
12.3 Estherville, Iowa
12.4 Grinnell, Iowa
12.5 Holstein, Iowa
12.6 General Information
11 7
13. Lime-Soda Ash Softening
13.1 Process Description
13.2 Webster City, Iowa
13.3 West Des Moines, Iowa
14. Capital and Operating Costs 133
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CONTENTS (Continued)
Section No. Page No.
15. Acknowledgements 139
16. References 140
17. Definitions 143
18. Appendix 147
Section
A Complete Mineral Analysis Reports 147
B Radium-226 Distribution 162
C Annual Capital and Operating Costs 176
D Ra-226 Analysis Modifications and Accuracy 186
E Salt Utilization by Ion Exchange 189
F Radiation Exposure Rates in Water Treatment Plants
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LIST OF FIGURES
Figure Page
No. No.
1. Map of Iowa Showing Location of Water Treatment Plants 13
2. Generalized Geologic Column for Iowa 22
3. Generalized Hydrogeologic Section of Iowa 23
4. Hydrogeologic Map of Iowa 26
5. Basic Reverse Osmosis Unit 33
6. Schematic Drawing of Hollow Fiber RO Unit 34
7. Cutaway Drawing of Permasep Permeator 34
8. Water System Schematic - Greenfield 37
9. Greenfield RO Plant - Multistage Pump and Permeator Banks 36
10. Plant Flow Diagram - Reverse Osmosis Plant - Greenfield 39
11. Ra-226 Distribution Treatment Process - Greenfield 44
12. Plant Flow Diagram - Adair , 50
13. Adair Greensand Filter 52
14. Ra-226 Distribution Treatment Process - Adair 7-18-74 55
15. RA-226 Distribution Treatment Process - Adair 5-18-75 56
16. Plant Flow Diagram - Stuart 16
17. Stuart Iron Removal Filters 17
18. Ra-226 Distribution Treatment Process - Stuart 63
19. Sodium Cation Exchange Reaction 64
20. Plant Flow Diagram - Eldon 69
21. Eldon Ion Exchange Softeners 68
22. Brine and Rinse Cycle - Eldon 73
23. Ra-226 Distribution Treatment Process - Eldon 75
VI1
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LIST OF FIGURES (Continued)
Figure No. Page No.
24. Plant Flow Diagram - Estherville 77
25. Ion Exchange Softeners - Estherville 78
26. Total Iron Analyses - Filter Run - Estherville 82
27. Brine and Rinse Cycle - Estherville 85
28. Ra-226 Distribution Treatment Process - Estherville 87
29. Plant Flow Diagram - Grinnell 89
30. Grinnell Ion Exchange Filters 93
31. Brine and Rinse Cycle - Grinnell 95
32. Ra-226 Distribution Treatment Process - Grinnell 96
33. Plant Flow Diagram - Holstein 99
34. Holstein Iron Removal Filters 100
35. Brine and Rinse Cycle - Hostein 105
36. Ra-226 Distribution Treatment Process - Holstein 106
37. Plant Flow Diagram - Webster City 116
38. Rectangular Permutit Solids Contact Unit - Webster City 120
8-13-74
39. Ra-226 Distribution Treatment Process - Webster City 2-20-1^ 124
40. Ra-226 Distribution Treatment Process - Webster City 125
41. Plant Flow Diagram - West Des Moines , 127
42. Solids Contact Unit - West Des Moines 129
43. Ra-266 Distribution Treatment Process - West Des Moines 132
44. Annual Capital and Operation Costs and Plant Operation 137
Maintenance Costs
F-l Exposure Rates on Surface of Greensand Tank, Adair, Iowa 197
F-2 Exposure Rates on Surface of Zeolite Tank, Estherville,
Iowa . 198
F-3 Exposure Rates on Surface of Zeolite Tank and Anthracite
Filter, Holstein, Iowa 199
vi ii
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LIST OF TABLES
Table Page
No. No.
1. Summary of Radium-226 Removal Efficiencies 2
2. Summary of Radium, Hardness and Iron Removals by Process 4
3. Radium-226 Levels - Iowa Finished Waters 17
4. Geologic and Hydrogeologic Units in Iowa 24
5. Radiological and Chemical Analysis - Greenfield 41
6. Radium-226, Hardness, Iron and TS Removals - Reverse Osmosis 40
7. RO Plant Operating Data - Greenfield 42
8. Type of Aeration, Detention and Filtration 48
9. Radiological and Chemical Analyses - Adair 51
10. Radium-226 and Iron Removals - Adair 53
11. Radiological and Chemical Analyses - Stuart 61
12. Operating Characteristics of Polystyrene Ion Exchange Resin 65
13. Radiological and Chemical Analyses - Eldon 70
14. Regeneration and Water Use Data - Eldon 72
15. Water Supply Wells - Estherville 76
16. Radiological and Chemical Analyses - Estherville 79
17. Radium-226, Hardness and Iron Removals - Estherville 80
18. Regeneration and Water Use Data - Estherville 84
19. Radiological and Chemical Analyses - Grinnell 90
20. Regeneration and Water Use Data - Grinnell 93
21. Water Supply Wells - Holstein 98
22. Radiological and Chemical Analyses - Holstein 101
23. Regeneration and Water Use Data - Holstein 103
IX
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TABLES (Continued)
Table No. Page No.
24. Salt and Media Radiological Analysis 109
25. Anthracite and Media Gamma Spectral Analysis 109
26. Ion Exchange Media 110
27. Sodium Increase Through Ion Exchange Plants 111
28. Radiological and Chemical Analyses - Webster City 118
29. Radiological and Chemical Analyses - Webster City 119
30. Radium-226, Hardness, Calcium and Magnesium Removals -
Webster City 121
31. Radiological and Chemical Analyses - West Des Moines 128
32. Radium-226, Hardness, Calcium and Magnesium Removals -
West Des Moines 130
33. Comparison of Annual Capital and Operation Costs and
Plant Operation and Maintenance Costs 135
A-l Complete Mineral Analysis - Greenfield 148
A-2 Complete Mineral Analysis - Adair 149
A-3 Complete Mineral Analysis - Stuart 150
A-4 Complete Mineral Analysis - Eldon 151
A-5 Complete Mineral Analysis - Estherville 153
A-6 Complete Mineral Analysis - Grinnell 155
A-7 Complete Mineral Analysis - Holstein 157
A-8 Complete Mineral Analysis - Webster City 159
A-9 Complete Mineral Analysis - West Des Moines 160
B-l Radium-226 Distribution in Treatment Process - Greenfield 163
B-2 Radium-226 Distribution in Treatment Process - Adair 9-18-74 164
B-3 Radium-226 Distribution in Treatment Process - Adair 5-13-75 165
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B-4 Radium-226 Distribution in Treatment Process - Stuart 166
B-5 Radium-226 Distribution in Treatment Process - Eldon 167
B-6 Radium-226 Distribution in Treatment Process - Estherville 169
B-7 Radium-226 Distribution in Treatment Process - Grinnell 170
B-8 Radium-226 Distribution in Treatment Process - Holstein 171
B-9 Radium-226 Distribution in Treatment Process - Webster
City 8-13-74 173
B-10 Radium-226 Distribution in Treatment Process - Webster
City 2-20-75 174
B-ll Radium-226 Distribution in Treatment Process - West
Des Moines 175
C-l Water Capital and Operating Costs - Greenfield 177
C-2 Water Capital and Operating Costs - Adair 178
C-3 Water Capital and Operating Costs - Stuart 179
C-4 Water Capital and Operating Costs - Eldon 180
C-5 Water Capital and Operating Costs - Estherville 181
C-6 Water Capital and Operating Costs - Grinnell 182
C-7 Water Capital and Operating Costs - Holstein 183
C-8 Water Capital and Operating Costs - Webster City 184
C-9 Water Capital and Operating Costs - West Des Moines 185
E-l Salt Utilization by Ion Exchange - Summary 190
E-2 Salt Utilization by Ion Exchange - Eldon 191
E-3 Salt Utilization by Ion Exchange - Estherville 192
E-4 Salt Utilization by Ion Exchange - Grinnell 193
E-5 Salt Utilization by Ion Exchange - Holstein 194
Xl
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SECTION I
SUMMARY AND CONCLUSIONS
On the basis of the literature search and chemical and radiological data
obtained from the nine public water supplies in this study, the following
conclusions are drawn:
1. High radium-226 water is associated primarily with the deep Jordan
sandstone formations (1000-3200 ft. deep) principally in southern
Iowa and with the Dakota sandstone formation (100-600 ft. deep) in
northwestern Iowa. Other studies by the State of Iowa and other
states indicate that surface waters have mean radium-226 concentra-
tions of only 0.10 pCi/1.
Radium-226 content of raw well water at the nine water treatment
plants studied ranged from a low of 5.7 pCi/1 in a Dakota sandstone
formation to a high of 49 pCi/1 in a Jordan sandstone formation.
2. Table I summarizes the radium-226 removal efficiency compared with
the concurrent iron and hardness removal efficiencies through plant
units. The divalent radium-226 removals, in general, parallel the
hardness, calcium and magnesium removals.
a. Reverse Osmosis - Overall removal of radium-226 was 96% as
compared with a concurrent hardness removal of 95% through a
battery of hollow fiber permeators at a product recovery of 69
percent, or the percent conversion of treated water produced
to well water pumped. Other corresponding chemical constitu-
ent removals were calcium, 95%, iron, 81% and total solids,
92%. The literature indicates that the membrane rejection of
divalent ions such as Ca and Mg is greater than for the mono-
valent ions Na and Cl and the study indicated the same
conclusion.
b. Iron Removal - Two of the water treatment plants utilized iron
removal only and all four zeolite softening plants used iron
removal for pretreatment. Radium-226 removal through the iron
removal units varied from a low of 12% using aeration, short
term aeration and iron filters to a high of 38% through aera-
tion, short term detention and continuous regene-ated potas
sium permanganate greensand filter. The concurrent iron
removal efficiencies were 85% and 98%, respectively. The
manner of radium removal is possibly adsorption or catalytic
action by the oxidation products deposited on the filter
media. In one survey at Estherville when an excessive
quantity of water was passed through the iron removal filter
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TABLE 1
Radium-226 Removal Efficiency
Comparison with Iron Hardness Removal Efficiencies
Percent Removals Through Plant Units
Well
Iron Filter Softening Sand
Ra-226 Iron Ra-266
Municipality %
Greenfield - RO
Adair 38
Greens and
Stuart 25
Iron Filter
Eldon 12
Estherville 11
Grinnell 15
Holstein 28
Webster City (3)
Clarifier #1
Clarifier #2
Webster City (4)
Clarifier #1
Clarifier #2
% %
96
98
97
85 96
81(1) 94
42(2) 97
97 93
68
57
88
96
Hardness Ra-266
% %
95
97
95
97
97
32 60
43
69 50
69
Filter Overall Ra-226
Hardness Ra-226 Hard, mg/1
% % %
96 95 14
13
16
96 97 49
95 95 5.7
97 97 6.7
96 98 13
15 85 48 6.1
29 96 78 7.8
West Des Moines
72
43
10(5) 12
75
50
9.3
(1) Poor removal due to long filter run.
(2) Aeration & settling only; no filtration.
(3) Lime softening only; no soda ash.
(4) Lime-soda ash treatment.
(5) Poor solids removal through filter selected.
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both the iron and radium concentrations in the filter efflu-
ent near the end of the filter run were greater than that in
the filter influent.
c. Sodium Cation Exchange Softening - Radium-226 removals were
excellent with the four sodium cation exchangers removing 93
to 96 percent of the radium while also removing 95 to 97 per-
cent of the hardness.
Two of the ion exchange softeners were run 10 percent past the
normal regeneration time to determine radium removal as the
exchange media was nearing complete exhaustion. The
data indicated radium removal continuing after hardness removal
capacity was exhausted.
In all of the ion exchange softener installations 6 to 25 per-
cent unsoftened water was bypassed around the softener and
blended with the finished water being pumped to the distribu-
tion system to provide sufficient calcium carbonate for depo-
sition of a protective coating on the water mains.
d. Lime-Soda Ash Softening - Overall removal of radium-226 by
softening and filtration can reach the 95 percent removal
range of the reverse osmosis and ion exchange processes if
hardness removal approaches 75-80%. Considerable variations
in radium removals were noted depending on chemical dosage,
pH range, magnesium removal, non-carbonate hardness removal
and filtration efficiency.
The use of soda ash in normal plant operation was restricted
due to a shortage of the chemical. A second survey conducted
at Webster City when soda ash became available indicated aver-
age radium and hardness removals of 92 and 69 percent respec-
tively in a primary upflow basin. A pH level of 10.85 during
this survey may have contributed to better removals when com-
pared with 10.1 pH levels in the two previous surveys.
Further solids removals by filtration gave a unit removal as
high as 50 percent for radium and 29 percent for hardness.
This removal of the unsettled softening precipitates was
obtained from a filter passing only 2 turbidity units in the
effluent. Poor radium and hardness removals were obtained
from a filter with poor turbidity removal.
3. Table 2 is a summary of the concentration and percent removals of
Ra-226, hardness and iron by the various treatment processes
employed by the nine municipal plants. Radium concentrations in
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Table 2
Summary Ra-226 Hardness and Iron Removals By Process
Concentration and Percent Removal
Sampl ing
Point
Iron Removal
Adair
Well Supply
Aeration- Detent ion
Iron Fi Iter Eff
Overal 1
Zeol i te Softening
El don
Well Supply
Iron Fi Iter Eff
Softener Eff
Overal 1
Zeolite Softening
Ra-226
pCi/1
13
13
8
*9
*3
1.9
*
0
38
38
12
96
96
Hardness
mg/1 %
375
360
10 97
97
1 ron
mg/1 %
1
1
0
2
0
0
.1
.2
.02
.0
.3
.05
0
98
98
85
83
97
Grinnel 1
Well Supply
Aeration- Detent ion
Iron Filter Eff
Softener Eff
Overal 1
Reverse Osmosis
6.7
5-7
0.2
15
96
97
385
387
11 97
97
Greenfield
Well Supply
RO Plant Eff
Overal 1
1*
0.06
96
96
610
29 95
95
0
0
c
.71
.*!
.03
TS
*2
93
96
mg/1 %
2160
16*
16*
92
92
Ra-226 Hardness
pCi/1
Stuart
~T5
1*
12
% mg/1 %
13
1*
25
1 ron
mg/J %
0.
1.
0.
9*
0
03
0
97
97
Esthervi 1 le
5.7
*.9
0.3
Holstei
13
10
7.2
0.5
915
11 915
9* *6 95
95 95
n
920
23 870
28 885
93 18 97
96 98
2.
0.
0.
1.
1.
0.
0.
0.
0
38
05
8
6
05
02
02
81
87
97
11
97
60
99
Ra-226
pCi/1 %
Lime Soda Ash Softening
• Webster Ci
Well Supply 6.1
Clarifier #1 1.9 68
Clarifier #2 2.6 57
Sand Fi Iter
Effluent 0.9 60
Overall 85
Hardness
mg/1 %
ty 8/13/7*
507
333 32
282 *3
260 15
*8
Ra-226
pCi/1 %
Webster Ci
7.8
0.9 88
0.3 96
0.3 50
96
Hardness
mg/1 %
ty 2/20/75
*82
150 69
150 69
106 29
78
Ra-226
pCi/1
West Des
9-3
2.6 72
2.35 JO
75
Hardness
% mg/1 %
Moines
376
215 *3
190 12
50
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the raw well water varied from a high of 49 pCi/1 to a low of 5.7
pCi/1. Radium concentrations in the plant effluent varied from a
high of 12 pCi/1 in one of the iron removal plants to a low 0.06
pCi/1 in the reverse osmosis plant. Percentage radium removals by
the ion exchange process are in the 95-98% range for both high and
low radium concentrations in the raw well waters.
Hardness concentrations in the raw well water varied from a high of
920 mg/1 to a low of 375 mg/1. There was no correlation of high
radium concentration with high hardness concentrations and the
highest radium concentration was associated with the lowest hard-
ness concentration among the supplies studied.
4. Radium-226 concentrations and total radioactivity at various stages
of the treatment process were used to determine a material balance
showing points of radium removal. Considering the difficulty in
obtaining adequate flow measurements in some plants, generally good
material balances were obtained.
As shown by the following data, there was a wide range of Ra-226
concentrations in the various waste waters during radium removal
operations.
Ra-226 Concentration in Water Treatment Wastes
Range of Composite Samples - Values in pCi/1
Reverse Osmosis Iron Removal Ion Exchanger Softener Filter
Reject Water Filter Backwash Backwash Rinse Sludge Backwash
43 80-636 7.8-94 114-1960 980-2300 50-90
5. With the exception of the lagooning of lime sludge and discharge of
wastes from one ion exchange softening plant to a municipal lagoon,
all wastes from the water treatment process are discharged to
watercourses ranging from intermittent watercourses to high dis-
charge streams. No complaints or reports of detrimental effects
have been received by the municipalities or state regulatory agency
regarding the discharges. Costs of treatment or removal of these
water treatment plant wastes were not determined.
The following data indicate the wide range of concentration of
the significant water treatment wastes produced by the various
treatment processes.
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Significant Water Treatment Waste Constituents
Concentrations in mg/1
Iron Filter Ion Exchange Brine Rinse Softener Filter
Backwash Range of Averages Sludge Backwash
Iron Total Solids Hardness Chlorides TS TS
69-320 54,000 to 16,000 to 9,500 to 72,000 to 739 to
130,000 39,000 120,000 145,000 4700
Likewise the proceeding data give the wide range of Ra-226 con-
centrations in these wastes.
The iron removal filter backwash iron concentrations of 69 to 320
mg/1 are largely suspended matter which is settleable and detention
can be used to reduce the suspended solids content below the gener-
ally suggested discharge requirement of 20 mg/1. Sand filter back-
wash following lime softening had total solids concentrations up to
4700 mg/1 and these wastes are also settleable and the supernatant
reusable.
During the brine rinse of the ion exchange media, chlorides of cal-
cium and magnesium and excess regenerant salt pass to wastes from
the softener. The above table indicates the total solids (largely
dissolved) increase to a range of 54,000 to 130,000 mg/1 and the
chlorides increase to a range of 9,500 to 120,000 mg/1 in the brine
rinse. The principle of mass action requires an excess of salt for
regeneration and only the middle one-third of the brine rinse is
high in sodium and might be used in some manner in subsequent
regenerations.
Softening sludges from upflow clarifier basins varied from 7.2 up
to 14.5% solids with both plants providing lagooning of these
wastes. One plant has initiated pumping of softener sludge to a
nearby cement plant which utilizes the sludge and added moisture in
the production of cement.
Sampling of all Iowa public water supplies and compilation of all
existing radiological data is not complete, but the data indicate
that of 567 public supplies sampled, over 120 supplies exceed the
existing radium-226 standard of 3 pCi/1 as contained in the 1962
Public Health Service Drinking Water Standards. The same data in-
dicates that an additional 144 supplies have values ranging between
0.5 and 2.9 pCi/1 or a total of 224 supplies out of 567 municipali-
ties exceeding a 0.5 pCi/1 value.
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7. Many sodium ion exchange softened waters where sodium replaces the
calcium and magnesium may provide more sodium than is allowed from
food on severely restricted diets of some patients suffering from
congestive heart failure, hypertension and certain kidney and liver
diseases. Likewise there have been many studies both here and
abroad suggesting that low coronary heart disease was associated
with hard water areas.
8. Total annual capital and operation costs were highly variable in a
range of 44 to 132c/l,000 gallons due to inclusion of distribution
capital and operation costs which could not be separated from
financial records. Plant operation and maintenance costs showed a
range of 12 to 45£/l,000 gallons. In general, the larger communi-
ties had lower unit costs.
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SECTION 2
RECOMMENDATIONS
The project study indicated that radium-226 removals in the range of
95% could be consistently expected from the reverse osmosis and sodium
ion exchange processes. Removal of radium-226 by the lime-soda ash
softening process was quite variable due to differences in chemical
dosages, operating controls and hardness removals. An additional
study would be desirable to confirm correlation of removal of radium
with other divalent ions.
The project study did not include a sufficient number of plants to de-
termine reliable cost data. Capital and operational costs for radium
removal and disposal of treatment wastes should be developed for a range
of plants based on different population ranges. The type of waste
materials generated from the reverse osmosis, ion exchange softening
and lime-soda ash softening processes and the methods, economics and
hazards of each disposal or storage method should be investigated.
Ultimate waste treatment and disposal requirements must be developed
prior to a study of disposal costs.
Additional research is needed to confirm or refute a finding of an in-
creased bone neoplasm mortality rate due to elevated radium-226 levels
as indicated in such studies as the 1964 Iowa-Illinois epidemiological
study.
Some suggestive evidence has indicated soft water is not as healthful
as hard or mineralized waters. A review of research on the relations
of heart disease to soft water suggests more definitive studies need to
be undertaken to resolve the question. On the other hand, there is con-
cern with sodium in drinking water with relation to congestive heart
failure, hypertension and certain kidney and liver diseases.
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SECTION 3
INTRODUCTION
This report and study were performed by the Iowa Department of Environmental
Quality in response to a contract between the Department and the U. S.
Environmental Protection Agency dated June 28, 1975, and is entitled
"DETERMINATION OF RADIUM REMOVAL EFFICIENCIES IN IOWA WATER SUPPLY TREATMENT
PROCESSES." The study is supported by the U. S. Environmental Protection by
grant to the State of Iowa, Contract No. 68-03-0491. In turn the Iowa
Department of Environmental Quality has contracted with the State Hygienic
Laboratory University of Iowa to provide radiological and mineral analyses
and technical consultation for completion of the radium removal study and the
project report.
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SECTION 4
OBJECTIVES
The primary purpose of the study was to sample and analyze potable waters
from nine municipal water treatment plants in the State of Iowa to
determine the efficiency of radium-226 removal in a variety of water
treatment processes. The U. S. Environmental Protection Agency requires
information on the efficiency and cost data in order to implement and
develop the limit on radium-226 concentration in the revised drinking
water standards to be promulgated under provisions of the Safe Drinking
Water Act. High natural radium-226 concentrations are common in water from
many middle west wells penetrating the deep sandstone formations of
Ordovician or older age as well as the Dakota sandstone formation.
Under the study, nine municipalities with a high naturally occurring
radium content over 5 pCi/liter in well water were selected which in-
cluded four different water treatment processes: lime-soda ash soften-
ing, sodium cation exchange softening, reverse osmosis and iron removal
filtration (including aeration and continuously regenerated greensand
filters). Sampling for radiological and chemical analyses was performed
to determine radium, hardness and other parameters on the raw deep well
supply and their removal percentages or amounts through various stages of
treatment processes. Samples were also taken on various discard waters,
regeneration waters and treatment media to assist in determining the fate
of the radium content through the treatment process.
A secondary objective was to determine capital and operating costs of the
various treatment processes for substantial removal of radium from the
high radium well waters.
10
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SECTION 5
STUDY AND SAMPLING PROCEDURES
SELECTION OF WATER SUPPLIES
Public water supplies to be included in the study were selected on the basis
of (1) a high raw water radium-226 content (greater than 5 pCi/1) (2) a
variety of treatment processes (3) availability of continuous operation
during the study and (4) a variety of municipal population served.
WATER TREATMENT PROCESSES
On the basis of including the four basic water treatment processes and
securing representative examples of these processes the following Iowa
municipalities were selected. A brief listing of pertinent water treatment
units and the 1970 populations are included as follows:
(1) Reverse Osmosis
Greenfield - (2212 population) Deep well and three reverse osmosis per-
meators furnish portion of total consumption.
(2) Iron Removal
Stuart - (1354 population) Deep well, aerator, settling and four pressure
iron removal filters.
Adair - (750 population) Deep well, aerator and two continuously regen-
erated greensand filters.
(3) Ion Exchange
Eldon - (1319 population) Deep well, aerator, pressure iron removal filter
and two pressure ion exchange softeners.
Estherville - (8108 population) Deep well, aerator, gravity iron removal
filters and four pressure ion exchange softeners.
Grinnell - (8402 population) Three deep wells, aerator, settling and three
pressure ion exchange softeners.
Holstein - (1445 population) Deep well, aerator, settling, pressure iron
removal filter and two pressure ion exchange softeners.
(4) Lime-Soda Ash Softening
Webster City - (8488 population) Two deep wells, aerator, two parallel
upflow clarifiers, recarbonation and four gravity and sand filters.
11
-------
West Des Moines - (16,441 population) Two deep wells, aerator, two series
upflow clarifiers, recarbonation and gravity sand filters.
Figure 1 is a map of Iowa giving the general location of municipalities
studied in the project.
SAMPLING PROGRAM
Samples were collected from wells furnishing the raw water supply and from
various stages through the treatment processes to determine changes and
removals of radium content and other pertinent chemical parameters. In
addition to the radiological and chemical concentration, flows or other
quantity data were obtained to determine whether plants were meeting
design rates and to provide data for determining a material balance of
radium-226 removals.
Wells
Samples were generally collected near the beginning of the pumping periods
and following longer pumping periods to determine any time related variability
in radium, hardness and other chemical parameters during pumping.
Aeration and Settling
Samples were collected of aerator effluents or effluents of settling units
preceeding iron removal filters or zeolite softeners to determine radium-226,
iron or other chemical parameter removals.
Iron Removal Filters
Samples were taken before and after filtration to determine removal efficien-
cies during various stages of the filtration cycle. Various types of
composite samples of the filter backwash were collected to determine iron
and radium loadings in the backwash water and radium removals by this treat-
ment process during the filtration cycle.
Ion Exchange Softening
Samples were collected of the influent and of the effluent soon after
regeneration, at 25% cycle, at mid-cycle, at the end of the softening cycle
just before breakthrough and at 110% of the cycle following breakthrough.
Additional samples were also collected from adjacent softeners at various
stages in the regeneration cycle to check removal efficiencies of radium-226,
hardness and other chemical parameters of all softening units.
Zeolite softener backwash was sampled by compositing and the flow measured
to determine radium-226 content as a part of a material balance through
this unit.
12
-------
tiYOM
^^SIOl/X
f
iPLYMOUTH
s
\tVOOOfURY
X *
OSCCOLA
o'aniCN
CHCROKCC
r
DICKINSON
CLAY
BUCNA VISTA
SAC
CMUET
* Esth
PALO ALTO
POCAHOMTAS
CALHOUN
KOSSUTH
irville
HVMBOLDT
VfCeSTCK
WINNfBAGO
HANCOCK
WHIOHT
HAMILTON
-» ^
WORTH
CCftRO 60HOO
FRANKLIN
HAROIN
H
FLOYD
BUTLER
GIWNDY
\
CHICKASAW
BLACK HAWK
1
—
FAYcrrc
BUCHANAN
\
_L
/
CLAYTON I
v
'MONONA
Isteil
Webster City
CRAWFORD
^HARRISON
CARROLL
GftCCNC
MDUBON\ OUTHHIC
ifOTTA WATTAMIE
\MIUS
IfRCMatrr
CASS
Adair
PAOC
BOOMC
STORY
ADA
in
Greenfi]
TAYLOR
MADISON
Stuart
eld
HIHGSOLD
MARSHALL
West })es_Molnes
WARREN
CLARKE
OCCATUR
LUCAS
WAYNC
gCNTON
Griniell
MAHASKA
MONHOC
APMHOOSE
WAPCLLO
DAVIS
JOHCS
Eldon
VAN OUflCN
Figure 1
State of Iowa
Location of Water Treatment Plants
Radium Removal Efficiency Study
-------
During the brine and rinse portion of the regeneration cycle composite
samples were collected when an increased salometer (indication of %
NaCl) degree reading indicated the regeneration brine and calcium and
magnesium ions were present in the waste discharge of the softener.
Curves were developed showing salometer degree, radium-226 and hardness
during this brine rinse cycle and radium removal was calculated as part
of a material balance.
Lime-Soda Ash Softening
Samples were collected of the influent and effluent of the suspended
solids contact softeners to determine radium-226 and other parameter
removals or additions through these clarifier units. Several samples
were generally collected during the operating day to determine treat-
ment efficiency variations. In addition, composite sludge drawoff
samples were collected and volume calculated to determine the radium-
226 and hardness removals and permit subsequent material balance
calculations.
Filtration
Samples were collected of sand or anthrafilt filter influents and
effluents to determine radium-226 removals as well as other chemical
constituent reductions. In addition composite samples were collected
of filter backwash and quantities recorded to determine radium-226
removals by this unit.
Reverse Osmosis
Raw and product water samples were collected from individual permeators
and combined permeator effluent to determine treatment variations and
removals of radium-226 and other chemical consitituents. Reject water
from the permeator was measured and sampled to determine radium-226 and
other chemical constituent concentrations.
TREATMENT PLANT CHARACTERISTICS
Complete details of plant design and operation including pertinent flow
rates, unit capacities, chemical additions, description of treatment
media, operating cycle times, storage volumes, well use during sampling
and other procedures which might affect process efficiencies were obtained.
ANALYTICAL PROCEDURES
The Iowa State Hygienic Laboratory under the direction of Dr. R. L.
Morris, Associate Director, performed the following analytical work.
14
-------
Radiological
Gross alpha and radium-226. Radium-226 analyses were completed by co-
precipitation with mixed barium and lead sulfates in accordance with
Standard Method ASTM D 2460-70 with necessary modifications as shown in
Appendix D. Calculations for the precision and accuracy of the radium
analysis are also included in Appendix D.
Chemical
Sleeted samples were analyzed for complete mineral and trace metals in
accordance with procedures contained in the 13th edition of "Standard
Methods for Examination of Water and Wastewater". The majority of chemical
determination were partial mineral analyses including such pertinent
parameters as total dissolved solids, hardness, calcium, magnesium,
alkalinity (T § P), pH, iron and chlorides depending on the type of treat-
ment process. The hardness and alkalinity determination are reported as
CaCOs whereas the other chemical determination are reported as the element.
The calcium and magnesium values would be multiplied by conversion factors
of 2.5 and 4.11 respectively to convert to the CaC03 equivalent when
determining hardness.
Field analyses including pH, hardness, calcium, magnesium, alkalinity and
other parameters were performed to determine critical changes and
appropriate times for sampling for more complete laboratory analyses. The
field analyses were not made a part of the report.
Duplicates of approximately 10% of the samples were collected and analyzed
by the laboratory to determine precision and accuracy of the analytical
work. Some duplicates of samples were submitted to the Radiochemistry and
Nuclear Engineering Facility of the Environmental Protection Agency
in Cincinnati, Ohio.
15
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SECTION 6
RADIOACTIVITY STUDIES IN IOWA WATER SUPPLIES
A long series of studies were begun in the State of Illinois by the
Argonne National Laboratory! with the discovery in 1948 of high
natural radioactivity in the drinking water of the adjoining munici-
pal water supplies. The radioactivity was identified as resulting
from radium-226 and other studies defined the boundaries of the
geographic region in Illinois in which the high radium waters were
present, the number of people involved and such metabolic factors
as the relative contribution of both food and water to the whole
body radium content of exposed individuals. The studies show that
surface waters had mean radium-226 concentrations of 0.10 pCi/1
whereas the mean radium-226 concentration of well water from the
deep sandstone (Cambrian and Ordovician rocks) varied from less
than 1 pCi/1 to over 25 pCi/1 with a mean concentration of 6.0
pCi/1. They concluded that the high radium water was associated
primarily with water from the St. Peter Sandstone.
The Iowa State Hygienic Laboratory began very limited sampling and
analysis of Iowa municipal ground water supplies for radioactive
isotopes in the 1950's. The water supplies sampled during this
period were primarily from the Jordan and St. Peter sandstones in
southeast Iowa. Morris and Klinsky of the Laboratory reported re-
sults of studies of radium-226 levels in eight water supplies and
on the efficiency of zeolite water softeners in the removal of
radium-226.
A memorandum from Ball^ of the Iowa State Hygienic Laboratory in 1964
summarized the Midwest Environmental Health Study results of radium-226
analyses on a limited number of Iowa public water supplies as follows:
Total towns sampled 241
Towns with radium in raw water (0.5 pCi/1) 151
Towns with radium in finished water
0.5 - 20 pCi/1 118
0.5 - 3.0 pCi/1 74
3.0 pCi/1 44
5.0 pCi/1 19
Towns removing radium during softening 33
Table 3, from the Midwest Study, lists the number of Iowa public water
supplies with the radium-226 range and populations served.
16
-------
TABLE 3
Radium Levels - Iowa Public Water Supplies - Finished Waters
Range-pCi/1
0.26-0.49
0.50-0.99
1.00-1.99
2.0 -2.99
3.0 -3.99
4.0 -4.99
5.0 -5.99
6.0 -6.99
7.0 -7.99
8.0 -9.99
10.0-14.99
15.0-19.99
20
Total
No. of Supplies
123
22
34
18
17
8
5
6
1
1
5
1
0
241
Population
581,269
48,359
88,426
93,989
118,089
43,240
3,859
10,752
4,952
906
5,570
1,045
0
1,000,456
The reporting of the elevated radium-226 concentration in Illinois and
lowa^ well water supplies along with studies documenting cases in which
relatively high levels of radium-226 deposited in the human skeleton
produced malignant neoplasms (bone cancer) pointed out the epidemic-
logical potential for dose-effect studies. In 1962, the Division of
Radiological Health of the Public Health Service, in cooperation with
the Argonne National Laboratory's Division of Radiological Physics
and the State Health Departments of Illinois and Iowa, initiated the
Midwest Environmental Health Study-^ to conduct an epidemiological in-
vestigation of human populations exposed to elevated levels of radium-
226 in drinking water. The Iowa State Hygienic Laboratory performed
the radiological analyses and compiled the data acquired over a
period of two years by the joint project.
17
-------
In 1962, the Public Health Service Drinking Water Standards established
a radium-226 concentration standard of 3 pCi/1. It had been shown that
long term ingestion of water containing 3 or more pCi radium-226 per liter
could result in a radium-226 total body burden at least twice that found
in the population exposed to lower levels.
One epidemiological approach following the midwest sampling and analysis
program was to compare a population of almost 1,000,000 people in 111
communities, 72 in Illinois and 39 in Iowa, having elevated radium-226
levels above 3 pCi/1 with a population with known exposure. Based on a
retrospective analysis of data from death certificates this population
group exhibited an adjusted bone neoplasm mortality rate of 1.41 death
per 100,000 compared with a rate of 1.14 in a control population. The
study concluded that confirmation and refutation of the finding will
require a prospective analytic epidemiological study. No further studies
were carried out.
o
A second study following the well sampling program was to determine
whether deciduous teeth are valid indications of long term low level
ingestion of environmental radium-226. Pools of deciduous teeth from
35 Illinois and Iowa communities were analyzed and the correlation between
radium-226 levels in water and deciduous teeth was found to be direct and
apparently linear.
During 1969, the Iowa State Hygienic Laboratory, with funds provided by
the Iowa State Department of Health, began a program which included
radiological analyses on all samples collected for complete mineral-
trace metals analyses. The State Department of Health funding of this
analytical program was discontinued during 1972 but the State Hygienic
Laboratory has continued the program to the extent possible with their
existing program budget.
Sampling of all Iowa public water supplies and compilation of all existing
radiological data is still not complete in 1974, but recent data indicates
that of 567 public supplies sampled, 120 supplies exceeded the existing
radium-226 standards of 3 pCi/1 as contained in the 1962 Public Health
Service Drinking Water Standards. The same data indicates that an
additional 144 public supplies had radium-226 values ranging between 0.5
and 2.9 pCi/1 or a total of 224 supplies out of 567 municipalities
exceeding the 0.5 pCi/1 value. The State of Iowa has over 800 public
water supplies but it is felt that the radiological sampling at this time
includes a majority of the high radium-226 content waters since an effort
has been made in the past to include the deep well supplies with a
potential for a high radium-226 content.
18
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SECTION 7
WATER MINERALIZATION AND HEALTH
9
Some suggestive, although not conclusive, evidence has been presented that
indicates soft water or a low total dissolved solids water may not be as
wholesome as hard or mineralized water. Whether this effect, if true, is
related to calcium and magnesium, other trace elements in mineralized water
or to the corrosiveness of soft water leaching some toxicant from water
piping, is not known at this time.
Winton and McCabe indicated a review of research on the relations of heart
disease to soft water during the past decade or more uncovered sufficient
correlation to suggest more definitive studies need to be undertaken to
resolve the question. In recent years, coronary heart disease (CHD) has
accounted for about 29 percent of all deaths in the United States and
continues to rank as the nation's leading killer. The following discussion
abstracts some of the review of the past research.
The correlation between the water constituents and cardiovascular disease
(CVD) began in 1957 when a Japanese agricultural chemistH showed data
linking acidity in river water with Japan's leading cause of death, cerebral
hemorrhage. Areas of Japan with more acid rivers had higher mortality from
this disease. At about the same time American investigators were directing
attention to the striking unequal geographical distribution of the United
States leading cause of death, CHD. States with low CHD were in the hard
water areas of the western plains and some areas of mid-south and the high
rate areas were predominantly along the east, west, and gulf coasts.
Correlations using state mortality data indicated that calcium and magnesium
were significantly and inversely correlated with CHD death rates. Studies
were also publishedl3 regarding similar correlation in England, Sweden, the
Netherlands, New York City, and counties in Oklahoma.
If there is a water factor influencing CHD or other cardiovascular disease,
it should be possible to demonstrate at what step in the development of the
disease it is operating. An international study found no correlation
between soft water and the degree of deposition and narrowing of the coronary
arteries. It has been well publicized that people with high blood cholesterol
and other lipids are more prone to develop CHD. One study was able to
decrease blood cholesterol and other lipids in men and women by doubling
the calcium intake. A similar study found no remarkable difference in
cholesterol when comparing men from hard water Omaha with a group from soft
water Winston-Salem. However, the extra calcium received from the hard
water was only a fraction of that received in the previous study. Another
study indicated magnesium protects against lipid deposits in rats. A
recent Canadiam study!-* indicates that magnesium is the element that is most
probably responsible for associations between cardiovascular mortality and
water hardness.
19
-------
Studies have suggested that corrosive soft water leaches cadmium from
galvanized pipes and that perhaps cadmium is the real factor. Cadmium
has been demonstrated as a causative factor in high blood pressure which
affects the course of CHD and CVD. Another theory has been proposed
that increased copper intake from copper water pipe may augment lipid
deposition in arteries.
Another problem that has cast some doubt on the wisdom of softening is
related to sodium. The increasing awareness of the health hazard of
sodium in the diet has indicated that sodium cycle ion exchange and the
use of soda ash for the removal of non-carbonate hardness must be viewed
with caution.
In 1963, the Heart Disease Program^ of the Public Health Service under-
took a national survey of drinking water for sodium content. The basis
of concern with sodium in drinking water is the treatment of patients
with congestive heart failure. The greatest problem of therapy is edema
associated with the disease. This edema, an excessive accumulation of
fluid in the tissues, is closely related to excessive retention of
sodium by the kidney. Dietary restriction of sodium is considered the
basic diet therapy along with a high intake of fluid (3.5 liters water
daily) to promote diuresis. Sodium may also be implicated in hypertension
and certain kidney and liver diseases.
The American Heart Association^ has defined a normal sodium intake of
3000 to 5000 ing/day compared with a severe restriction of only 200-500
mg for treatment of some cases of congestive heart failure. An extremely
rigid selection of food is required and the sodium content of the water
supply must also be considered. Some zeolite (ion exchange) softened
water where sodium replaces the calcium and magnesium may provide two or
three times more sodium than is allowed from food on a severely restricted
diet.
20
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SECTION 8
HYDROGEOLOGY
GENERAL
The geologic framework of Iowa's ground-water reservoir -*-' is summarized
in table 4 and figures 2 and 3. The bottom of the reservoir is the
Precambrian crystalline complex, which occurs at a depth of about 5,200
feet in southwestern Iowa and rises to the surface in extreme north-
western Iowa and to within 800 feet of the surface in northeastern Iowa.
Overlying this complex is a succession of consolidated sedimentary
strata of Paleozoic age that are dominantly sandstones and dolomites in
the lower part, and shales, dolomites, and limestones in the upper part.
These strata have been downwarped into a broad trough, known as the Iowa
Basin (Figure 4). The surface of the dipping Paleozoic strata was bev-
elled by erosion, thus exposing older Paleozoic strata in the northeast-
ern and northwestern parts of the state and forming the extensive
recharge areas of the Paleozoic aquifers in northeastern Iowa and south-
ern Minnesota. The deep, highly productive artesian aquifers in Iowa
are a considerable distance from these recharge sources.
The six principal water-yielding rock units in the Iowa reservoir are
the surficial deposits, the Dakota Sandstone of Cretacous age, lime-
stones and dolomites of Mississipian age, limestones and dolomites of
Silurian and Devonian age, the Cambrian and Ordovician sandstones and
dolomites, and the Dresbach sandstones of Cambrian age (Table 4). The
most consistently productive units are the Cambrian and Ordovician
sandstones and dolomites.
Dakota Sandstone Aquifer
Strata of Cretaceous age, principally the Dakota Sandstone (Table 4),
comprise the chief bedrock aquifer in northwestern Iowa and less exten-
sively in western and southwestern Iowa. These rocks are present across
most of the northwestern part of the state as far east as Kossuth,
Wright, Webster, Greene, and Guthrie Counties, and as irregular remnants
as far south as Montgomery and Page counties (Figure 4). This aquifer
covers about 20 percent of the state with dissolved solids concentration
of less than 500 mg/1 over less than 5 percent of the state and dis-
solved solids content of less than 1,000 mg/1 over about 12 percent of
the state.
Maximum thickness of the full Cretaceous System is somewhat more than
400 feet in central Sioux and Osceola counties, from where it thins
northwestward and southeastward. The depth to the Dakota Sandstone
varies considerably. Generally, in the northwestern counties it is
21
-------
Formation
Wisconsin
rcj^£^ Songcmon-
Qfiitsfe-
rfr Yarmoufh-
—^ Kansqn
gmrfljrr —
^f-e-^ Aftonion-
N'ebroskan
sh
Graneros
shale
.__. =
( ____ Dakota fm
ft Dodge fm
Wabour.see
groups
pi' Lc^5^ng group
KonsCi City
?§X^;S group
=^=^, Marmaton
qrouo
Cherokee
group
s
Y
S
T
E
M
: Ste Gf"6veve fm
-J*.. St LO-j.s-
i-.?: SR£raen_
Worse* fm
6u-lir>gton Is
C.Iy is
"Hcrnpton" fm •
Mo pie Mill
shole
cr
r-
Ckr
co
Figure 2
GENERALIZED
GEOLOGIC COLUMN
FOR
IOWA
Approximate vertical scoie
in feet
.——^"\ Sn«le (clay-Silt
-^'j m Pleistocene)
Sandstone (sand
in P'eittocene)
Metamorjhic
end igneous
crystalline rocks
IOWA GEOLOGICAL SURVEY
1952
22
-------
L.
3
CD
Cfl
S
o
C
o
•H
4J
O
QJ
CO
u
•l-l
H
O
OJ
M)
O
01
N
-------
TABLE 4
Geologic and Hydrogeolic Units in Iowa
"
1
"5
0
Ct
p
AGE
Ouatemory
Cretaceous
—
MissFssipP'on
»—«
>lunan
ROCK UNIT
Alluvnim
Gtaaal drift (undiftermntiaied
Buried channel deposits
Carlile Formation
Graneros Formation
Dakota Group
Virgil Series
Missouri Series
Des Uoinet Series
M«,0m«c ,.«
Oioge Series
Kino>rhook Series
Mople Mill Shale
Sheffield Formation
L me Creek Fgrmofion
N G^oron Serves
A'eiandnan Senes
MO,J(».,0 f.,n,=!w
Goieno Formotjon
St Peter Sondjtone
Jordan Sandstone
S L o
Frorcoruo Sandstone
DreiDOCh Group
Sioji Ouortnte
DESCRIPTION
Sond. grovel, *m and clay
Predominantly till
containing scattered
vregular bodies of sont
and gravejl
Sand, gravel, silt and clay
Shale
Shale oM limestone
Shale; sandstones,
mostty thin
Limestone, sandy
cherly
Limei'one, oolitic, and
dolomite, cherty
ower part
owa
)otom-te, locally cherty
hoie and dolom-te
imeslone and thin
tone in SE Iowa
andstone
herty
ordilone
lolomite
OMlvont «^4 «olt
Ondslore
jO'tute
oo'»e sandstorms,
ystoll-n* rocis
HYDROGEOLOGJC UNIT
Surficia! equifer
Aquic'ode
*
A quietude
Minor aquifer
OQu'fer
r,t.,:".'::icjl
s*"°"
WATER-BEARING CHARACTERISTICS
Fair to large yields
Low yields
Small to large yields
Does not yield water
H4gh to fair yields
Lo* yields only from
limestone and sandstone
Fair to low yields
Does not yield water
High to fa'r yields
in northwest iovc
LOW yelds
engrail} floes not yield water , fair
Fair yields
High yields
Does not yieid »atf
Migr- tc :o» j-efli
Met son cr ypiovolconic a*ea
\J S"0'iQ/Opr«c nomenclature Ooes r>o' confoff*' to U S GeoiOCjCOt Sa'-ej
Source: Water Resources of Iowa - 1970
24
-------
necessary to drill between 250 and 600 feet to penetrate the Dakota
aquifer, whereas in the eastern areas the Dakota usually can be reached
at between 100 and 350 feet.
The Dakota aquifer generally can be counted on to produce sufficient
water for all rural and many municipal requirements. Even where the
aquifer is only moderately thick, many wells have been developed to
yield 50 to 100 gpm. Some municipal wells in Osceola, O'Brien, Sioux
and Cherokee Counties have been tested at 350 and 750 gpm.
Cambrian-Ordovician Aquifer
The Cambrian-Ordovician aquifer is widespread throughout the State of
Iowa (Figure 4). The aquifer consists of three water bearing forma-
tions, the St. Peter Sandstone and Prairie du Chien Formation of the
Ordovician Age and the Jordan Sandstone of the Cambrian Age (Table 4).
The St. Peter Sandstone formation rarely reaches a thickness of over 50
feet. It is capable of producing wells yielding 50 gpm but is usually
cased off when drilling wells to this aquifer to prevent caving or to
shut off poorer quality water. The underlying Prairie du Chien Forma-
tion is several hundred feet thick in eastern and southern Iowa but it
thins out towards the northwest. This formation is believed to yield
significant amounts of water to wells penetrating the Cambrian-
Ordovician aquifer; however, its performance is generally overshadowed
by the underlying Jordan Sandstone. The Prairie du Chien is the prin-
ciple water producing unit for some wells in south central Iowa. The
Jordan Sandstone is the principal water producing unit and is penetrated
by practically all wells drilled to the Cambrian-Ordovician aquifers.
This sandstone thickness ranges from 75 to 125 feet in southwestern
Iowa.
The dissolved solids concentration in water from the Jordan Sandstone is
often less than 300 mg/1 in the northeast and increases toward the west
and south. Water with less than 500 mg/1 of dissolved solids is found
in the Jordan aquifer over more than 20 percent of the state, less than
1,000 mg/1 in more than 35 percent, and less than 1,500 mg/1 in over 60
percent of the state.
The Cambian-Ordovician aquifer (principally the Jordan Sandstone) con-
sistently yields several hundred to more than one thousand gpm of water
from individual wells throughout the eastern three-fourths of the state.
The aquifer is present beneath younger Paleozoic rocks at progressively
greater depths to the southwest and southeast. The depth to the top of
the aquifer in southwestern Iowa, the deepest part of the Iowa Basin, is
about 3,200 feet (Figure 3). The total thickness of the water bearing
unit ranges from 0 to 600 feet in eastern Iowa and from 0 to 400 feet in
the western part of the state; the average thickness throughout its
subsurface extent is generally between 400 to 500 feet.
25
-------
M/ \ V .. . 1 ,,....„»
--i*/..- •-r*---'^^- s\----^-*-'^'-- I
. j./\--:--^..JKj'i.J
EXPLANATION
Dakota aquifer
(Unconformably ovtrlid Paltozoic
rocki)
Pennsylvonian rocks
Hydrogeologic contact, aisned -«r,e'c
concealed by Cretacsous bedrock
-<•: cf liwa fi-jsm, showing
:.•""r on •;••" ~lunqe
Mississippian aquifer
Devonian aquiclude
Silurian-Devonian aquifer
Maquoketa aquicludt
(Yitlds woUr locally in NW Iowa)
Cambrian-Ordovician aquifer
(Includes Goltno-Platttvlllt racki
in NE Iowa and Drttbach aquiftr
in NW Iowa)
Precombrian rocks
Mdnson cryptovolcanic rocks
Hydrogeologic Map of Iowa
Figure 4
-------
The aquifer is utilized extensively by municipalities and industries in
the eastern three-fourths of the state. Many small communities in cen-
tral and southern Iowa also utilize the aquifer because the overlying
rocks do not yield enough water or the water is highly mineralized.
Yields of up to 1,000 gpm are obtainable in most of the northeastern
one-half of the state. Limited well data indicate that yields of only
100 to 300 gpm are available in much of the southwestern quarter of the
state.
Significant lowering of the aquifer's pressure head has occurred at a
number of localities where large amounts of water are pumped from the
aquifer. Loss of pressure head in the vicinity of wells pumping from
the aquifer have been recorded at Ottumwa (100 feet in 70 years),
Grinnell (100 feet in 80 years), Des Moines area (50 feet in one year)
and a number of other smaller communities in southeastern Iowa.
PROJECT STUDY WELL INFORMATION
Information obtained from the Iowa Geological Survey on the wells sam-
pled during the project study summarizes the well depth, casing data and
principal water producing zones. All municipalities utilize the Jordan
sandstone as the principal water producing formation with the exception
of Holstein which obtains waters from the shallower Dakota sandstone
formation.
The Adair town well,drilled in 1968 by Thorpe Well Company to a depth of
2700 feet, is cased from surface to 1183' with 8" casing and from 1180-
2475' with 5" casing. The casing is cemented from top to bottom and
extends 80' below the top of the Prairie du Chien. The principal pro-
ducing zone is the Jordan sandstone and some water may be obtained from
the lower Prairie du Chien formation.
The Eldon town well was drilled in 1961 by Thorpe Well Company to a
depth of 1901 feet. Construction consists of 12" casing to 260', 10"
casing from 260' to 775' and 8" casing from 775' to 1590', about 359'
below the top of the Prairie du Chien. The entire length of casing is
grouted with cement. The principal source is the Jordan with some water
entering from the lower Prairie du Chien and from the St. Lawrence
Dolomite formation.
The Estherville city well was drilled in 1965 by Layne-Western Company
to a depth of 750 feet into the St. Lawrence. It was cased with 462' of
16" casing 0-462' into top of the St. Peter Sandstone and is grouted
with cement to 462'. The source of water is the interval from the St.
Peter Sandstone through the St. Lawrence Dolomite.
27
-------
The Greenfield town well was drilled in 1929 by Layne-Bowler and rebuilt
by Thorpe Well Company in 1967. The depth is 3467' and reportedly cased
from surface to 3100'. The producing source apparently is the Prairie
du Chien-Jordan-upper St. Lawrence sequence.
The Grinnell city No. 6 well was drilled in 1954-5 by Thorpe Well
Company. The original depth was 2970' into Mt. Simon Sandstone but was
plugged back to 2550' on top of Franconia siltstone and dolomite. The
casing record shows 700' of 19" casing 0-700', cemented in; 1325' of 12"
casing 675-2000', cemented in; and 710' of 10" casing 1975'-2685'. After
the well was plugged back to 2550' the casing was perforated opposite
the Jordan and St. Lawrence Formations which are the producing zones.
Three other similar wells are drilled to depths of 2250' to 2550'.
The Holstein well No. 1 was drilled 1937 by Thorpe Well Company to a
depth of 644' with 95' of well screen. Only a partial log is available
but a log of an adjacent well gives the Dakota Sandstone as the principal
water bearing formation at 610'.
The Stuart town well was drilled in 1962 by Thorpe Well Company to a depth
of 2801 feet into St. Lawrence Dolomite. Construction consists of 260'
of 22" casing 0-260'; 832' of 14" casing 0-832'; and 8" casing set at
2375* about 41' into the upper part of the Prairie du Chien, and grouted
in with cement back into the 14" casing. The Jordan is the principal
producing zone although some water probably is derived from the Prairie
du Chien and perhaps the St. Lawrence formations.
The Webster City No. 5 city well was drilled in 1954 by Thorpe Well Company
to a depth of 2005' into St. Lawrence Dolomite. The casing record is
incomplete, but 12" casing reportedly extends to 1446' into the St. Peter
or to 1500' into the Upper Prairie du Chien. There is no report on
whether the casing was cemented in. Probably the Jordan is the main
producing zone with some water coming in from the Prairie du Chien and St.
Lawrence formations. A second well of identical depth and similar
construction is also in use.
The West Des Moines city well was drilled in 1967 by L. F. Winslow to a
depth of 2460' into St. Lawrence Dolomite. The casing record shows 48'
of 30" casing, 0-48; 412' of 16" casing, 0-412; and 1613' of 10" casing
from 412' to 2025', about 62' into upper part of the Prairie du Chien
Dolomite. The casing reportedly is cemented from top to bottom. Water
is obtained from the Prairie du Chien and Jordan formations. A second
well with similar characteristics is also in use.
28
-------
SECTION 9
WATER TREATMENT PLANT WASTES
REVERSE OSMOSIS REJECT WATER DISPOSAL
Normally iron, calcium, and other ions removed with the reject water remain
in solution and normally large amounts of pretreatment chemicals are not
added in the process. If the clear reject water from the permeators discharge
to join the effluent from the municipal sewer system the total would yield
an effluent similar to the untreated hard water. The reject water may contain
up to three times the total solids present in the raw well water.
SPENT BRINE DISPOSAL
One of the problems created by sodium ion-exchange softening is the
disposal of spent brine from the regeneration cycle in view of increas-
ing water pollution control requirements. This disposal problem be-
comes more sensitive when considering the concentration of radioactive
isotopes. The backwash water preceeding the regeneration cycle may
contain small amounts of iron or organic material. The waste products
from the brine and rinse cycle are composed principally of the chlor-
ides of calcium and magnesium and the excess salt necessary for regen-
eration since an equivalent amount of hardness is not removed for the
amount of salt used.
The total wastewater may vary from 2 to 10% of the amount of water
softened. The wastewater will contain chloride ions (principally
sodium, calcium and magnesium compounds) proportional to the amount of
salt used in regeneration. This will usually be .4 - .6 Ibs of salt
per 1000 grains of hardness removed. The amount of salt to be dis-
posed of in the wastewater may be approximated by the formula C = 35SH,
in which C represents the chloride ion expressed in pound per million
gallons, S is the salt, in pounds per 1000 grains of hardness removed
and H is the reduction of hardness in mg/1 of calcium carbonate. The
total solids in a composite sample of a typical spent brine may vary
from an average concentrations of 50,000 to 100,000 mg/1 to a maximum
concentration of 70,000 to 200,000 mg/1.
Discharge of brine wastes onto pasture land can create "slugs" of high
total dissolved solids water detrimental to livestock watering uses.
Likewise discharge into a watercourse may cause damage to fish life.
Discharge into storage ponds may infiltrate into ground water supplies
and cause long term damage. Waste brines in a sanitary sewer system
may seriously upset the biological processes in sewage treatment
plants especially if "slugs" of highly concentrated brine flow directly
to the plant. In the State of Iowa which has a large number of ion
exchange softening plants there have been few reported detrimental effects
from the discharge of brine waste even where such discharge is into an
intermittent water course through pasture land.
29
-------
Several alternate disposal methods have been proposed and discussed. Paul
D. Haney24 in a report given as a part of an A.W.W.A. Committee Report
suggested several disposal methods.
1. Evaporation ponds.
Except under very unusual conditions, evaporation does not appear to
offer satisfactory means of disposal of ion exchange plant wastes. Studies
in Kansas indicated evaporation of oil field brine was less than the
rainfall. Evaporation data for fresh waters are not applicable to
brines because of the lowering of the vapor pressure by the dissolved
salts. Disposal of residual salts would be a problem. Where soils
are porous, watertight ponds are expensive to construct and experience
indicates many are seepage ponds.
2. Uncontrolled Dilution.
Discharge of the waste brine into a watercourse is the most common and
offers the most economical means of disposal, provided adequate dilu-
tion is available. Stream flow must be sufficient to provide dilution
to a level to protect fish life and other downstream water uses.
3. Controlled Dilution
Disposal by controlled dilution requires short term or long term
storage with discharge into a stream to keep salt content lower than
the maximum allowable water quality standard.
4. Brine Disposal Wells
Brine wells may provide a means of disposing of spent brine but it may
be feasible only in the oil well field areas. Brine treatment may also
be necessary for conditioning before injection into the formations re-
ceiving the brine.
5. Brine Reclamation
Only a portion of the partially spent brine could be used for subsequent
regeneration. In general the first one-third of the spent brine from
the brine rinse would contain 80% of the hardness. These calcium and
magnesium ions interfere with the regneration and decrease the exchange
capacity. The middle one-third of brine rinse is high in sodium and
might be used in subsequent regeneration to backwash the softener or
used initially in the regeneration followed by sufficient fresh brine
to attain the desired capacity. The principle of mass action requires
an excess of salt for regeneration. Some reduced salt costs and a re-
duction in the amount of spent brine requiring disposal are benefits
for reclamation which must be weighed against cost of additional piping
and spent brine holding tanks.
30
-------
LIME-SODA ASH SOFTENING WASTE DISPOSAL
Lime-Soda Ash Sludge
Discharge of water treatment plant wastes into a watercourse, histori-
cally the most widely used method of such disposal, may soon be eliminated
as an acceptable practice. Several years ago, a vast majority of plants
disposed of their sludges in this manner but recent Federal and State
regulations now prohibit the discharge of waste sludges to streams.
The sludge produced during the softening process consists principally
of calcium carbonate but contains varying amounts of magnesium hydroxide,
aluminum hydroxide, or other coagulants. The type of water treated and
the degree of softening practiced will determine the amount of these
constituents. Spent lime sludge may be concentrated up to 10 percent
solids in clarifier basins.
Given a prohibition against releasing sludge to streams, there are four
basic alternatives. They are:
1. Lagooning
2. Disposal on land
3. Release to the sewer
4. Reclamation and reuse of chemicals
When direct discharge into a water course is not used, lagooning ranks
high in popularity particularly for lime sludges. Lagoons are most
commonly used with two or more basins operated alternately so that the
excess moisture may be skimmed off or permitted to evaporate. When
sufficiently dry to be moved, the sludge may be used to raise the dikes,
used for landfill, or as soil sweetner. It may be economically feasible
to pump lime sludge several miles to inexpensive lagoon areas.
Dewatering by a variety of means and final disposal on land either in
a landfill or for agricultural use is a growing method of lime sludge
disposal. Dewatering can be accomplished by vacuum filters, belt filter
presses, pressure filters and centrifuges. Studies in the State of Iowa
indicate the vacuum filter may be the simplest and most economical method.
Discharge of sludges to sewers may cause some problems in clogging of
flat sewers and affect sewage treatment plant operations. In some in-
stances there has been improvement of sedimentation or in reduction of
phosphates in sewage. The volume of spent lime solids is much greater
than the amount of 0.2 pounds of sewage solids contributed per capita
per day. Likewise, the calcium carbonate comprising a high percentage
of the spent lime solids would increase the normal digester alkalinity
many times which would stop biological activity of the anaerobic digester.
31
-------
In one Iowa waste water treatment plant, spent lime solids were dis-
charged to the waste water plant for one week. Pumping of the settled
solids to an incinerator of the fluidized bed type caused the lime in
the sludge to build up a thick coating on the sand particles resulting
in clogging of the reactor and the discharge to the sewer was termin-
ated.
Recalcination of softening plant sludges for recovery of lime is
practiced in a very few large plants. As indicated by the 1972 AWWA
Committee Report , "Disposal of Wastes from Water Treatment Plants",
fluidized bed reactors are feasible for 20 ton capabilities while
rotary kiln operations required 40 tons. Therefore, recalcination
is feasible only in the larger plants. One Iowa recalcination
installation serving a population of 25,000 was constructed in 1948
but has since been abandoned.
A unique disposal method which has just been initiated by the City of
West Des Moines is pumping of the lime sludge to a nearby cement plant
which utilizes the sludge and added moisture in the production of
cement. Consideration is also being given to reconstituting the dried
lagooned lime sludge and also utilizing this sludge in the cement
manufacture.
Filter Backwash Water
Recovery of filter backwash water appears to be gaining in popularity
and undoubtedly will become more common. When coagulation is used,
the filter backwash water is retained in a wash water holding tank or
backwash water clarifier and returned at about a 5 percent rate to the
plant inlet ahead of any chemical additions. The procedure not only
recovers all of the waste water, but may improve the coagulation or
softening process by providing nuclei for floe formation.
32
-------
SECTION 10
REVERSE OSMOSIS DESALTING
SECTION 10.1
PROCESS DESCRIPTION
When high hardness waters of different concentrations are separated by
a semi-permeable membrane, water from the less concentrated side will
migrate through the membrane to the more concentrated side in an attempt
to equalize the concentrations. The semi-permeable membrane allows
water, but not dissolved solids to pass through it. This physical chem-
ical phenomenon is known as osmosis. During osmosis the volume of the
more concentrated solution will increase with a resulting pressure in-
crease. There is an effective pressure gradient across the membrane
in the direction of flow of the water. This driving pressure for the
flow of pure water is known as osmotic pressure. By putting sufficient
hydraulic pressure on the more concentrated side, the osmotic pressure
gradient can be overcome and an effective pressure gradient in the oppo-
site direction can be imposed. This creates a flow of water in the
direction opposite of normal osmosis, thus it is referred to as reverse.
osmosis
18
See Figure 5.
Piessutu
Saline
Water
Freshwater
I
Product Water
Brine
Figure 5
Basic RO Unit
In the reverse osmosis desalting process the high hardness water is
pressurized and piped into a. reverse osmosis unit where relatively
pure water diffuses through the semi-permeable membrane and becomes
the product water leaving a concentrated "reject" water. Character-
istic of essentially all reverse osmosis membranes, rejection of
divalent ions such as Ca, Mg and SO^ is much greater than for the
monovalent ions Na and Cl.
33
-------
The DuPont Permasep Permeators used at Greenfield, Iowa utilize the
hollow fiber concept. Membrane materials have been formed into hollow
fibers which may measure from 25 to 250 microns in diameter (approxi-
mately 0.001 to 0.01 inch). These very small diameter fibers can
withstand high pressures. Bundles of these fibers are sealed together
at one end and then cut to open the fiber ends and placed in a pressure
vessel. The pressurized feed water is on the outside of the hollow
fibers. The water permeates through the hollow fiber wall and into
the bore leaving most of the dissolved solids and other contaminants
behind. Simultaneously the waste stream (reject) water flows from
another port in the unit carrying out the high dissolved solids
content. The hollow fiber reverse osmosis concept is illustrated
in figures 6 and 7.
FEED
PERMEATE
Figure 6
Schematic Diagram of Hollow Fiber
Reverse Osmosis Unit
SNAP RING
PERMEATE
END PLATE
FIBER
CONCENTRATE
•0' RING SEAL
SHELL POROUS FEED END PLATE
DISTRIBUTOR TUBE
CUTAWAY DRAWING OF PERMASEP' PERMEATOR
Figure 7
34
-------
Pretreatment of the feed water is necessary to prevent fouling of the
membranes by suspended solids, iron, manganese and precipitation of
calcium carbonate and magnesium hydroxide.
Product water recovery, the amount of finished water obtained from the
feed water, can be varied. Normal recovery ranges for municipal in-
stallations may be in the 70 to 90% range, usually limited by the waste
stream (reject) water concentrations of certain ions which can become
supersaturated and precipitate.
35
-------
SECTION 10.2
GREENFIELD
BACKGROUND DATA
Greenfield is the County seat of Adair County and is located about 60
miles southwest of Des Moines. Greenfield is a typical small rural
Iowa community, located in an agricultural area which is not heavily
populated. The population of Adair County was 9,487 in 1970. The
population of the county has been showing significant declines over
the past four decades. The City of Greenfield had a 1970 population
of 2,212 which was a slight drop from 2,243 in 1960.
The usual water supply for the town is an impoundment of surface water.
The quality of this water is very good, with a total solids content of
about 200mg/l. But during periods of drought, the supply of good sur-
face water decreases, and the town must supplement its supply with
water from a 3,500 foot well that taps into the Jordan Aquifer. Un-
fortunately, the deepwell water is of a poor brackish quality, with a
total solids (TS) content of more than 2,200 mg/1. In 1971 Greenfield
installed a reverse osmosis desalting plant to treat this well water,
thus becoming the first municipality owned reverse osmosis desalting
plant in the nation. Figure 8 is a schematic diagram of both of Green-
field's water treatment facilities. Figure 9 indicates the arrangement
of the reverse osmosis unite within the plant.
Greenfield RO Plant
Figure 9
36
-------
DISTRIBUTION
SYSTEM
WELL (I)
CARTRIDGE
EM ERG.
DUMP
POLY
ELECT
,
T
c
I
CaO-H20
I AL2S°4
BOOSTERS
(NOT NORMALLY
USED)
60,000 GAL.
ELEVATED TANK
WASH
BRINE
->-
CALGON
-O-H3
AERATOR
CL
. REVERSE
OSMOSIS
PUMPS
REVERSE
OSMOSIS
UNITS
STORM SEWER
' (MIXED W/SEWAGE
PLANT EFFLUENT)
Figure 8
WATER SYSTEM SCHEMATIC-GREENFIELD
-------
Reverse Osmosis Treatment Facilities
Figure 10 is a flow diagram of Greendfield's reverse osmosis plant ^.
These reverse osmosis treatment facilities have a capacity of 150,000
gpd. The equipment consists of three banks of reverse osmosis permea-
tors. The equipment was installed in the basement of the City's
existing water treatment facilities in a space 25* x 25' x 12'. The
permeators are DuPont "Permasep" penneators which consist of aluminum
cylinders (about 5V diameter by 48" in length) which serve as pressure
vessels housing about a million hollow nylon fibers each. Hollow fiber
reverse osmosis units are described in section 9.1.
Water from the deep well enters the plant at 50 psi pressure. It is
filtered through 10-micron Filterite depth-type cartridge filters which
remove suspended solids that might cause fouling problems.
Sulfuric acid is added at a rate of about 160 mg/1 to the raw feed water
to lower the pH from 7.2 to 5.5. The acid converts the bicarbonate to
carbon dioxide which reduces the possibility of precipitation of calcium
carbonate. Further, there is about 1.6 mg/1 of ferrous iron in the raw
water. Iron is more likely to remain in solution at the lower pH and
thus can be rejected by the permeator. No additional pretreatment to
remove iron is used.
Sodium hexametaphosphate is added to the raw feed water at 16 mg/1 be-
fore it enters the permeators. This sequesters the calcium, thereby
inhibiting the precipitation of calcium sulfate; it also aids in iron
precipitation control.
The pretreated water enters the high pressure (400 psi) Gould multi-
stage centrifugal pumps which feed the permeators. By reverse osmosis,
these permeators remove the most unwanted dissolved solids from the
feed water, producing product water at a recovery rate of about 69
percent.
Post treatment of the product water consists of decarbonation by means
of an aerator, addition of soda ash to raise the pH to the 7-8 range,
and addition of chlorine. The product water then enters the clearwell
for mixing with the water from the surface water treatment plant.
Reject water from the permeators discharges by way of a storm sewer to
join the effluent from the municipal sewage system to yield a total
effluent very similar to the one obtained when untreated brackish water
was used prior to the acquisition of the reverse osmosis plant.
38
-------
Figure 10
Flow Diagram
Greenfield, Iowa - Population 2,212
Reverse Osmosis Desalting Plant
August 8,
Well No 1 Depth 3467 ft
Capacity 300 gpm
RO capacity 150,000 gpd
Parameter and
% Removal
Ra-226 Hardness Iron
pCi/1 mg/1 mg/1
-Well
10 Micron Cartridge Filter
.Sulfuric Acid 150 mg/1
•Calgon 16 mg/1
High pressure pumps 50 gpm
400 psi
3 Permeator Uni ts
Total capacity 150,000 gpd
5i" diam 48" length cylinders
Hollow fiber
' »-31% reject water to waste
Permeator Eff1uent
Decarbonator
(Aerator)
Soda Ash
Cl,
0.6
95.7
Overall Removal 95-7
Clear Well
Transfer pumps
Surface Storage
140,000 gal
High service pumps
Distribution System
610 1.6
29 0.3
95.2 81.2
95.2 81.2
39
-------
Reverse Osmosis Performance
Table 5 is a tabulation of the radiological and chemical analyses per-
formed on samples collected from the deep well and various stages in
the reverse osmosis units. Additional mineral analyess are
shown in Appendix A. Percent removals of rauj.um-226, hardness and
iron are also shown in figure 10.
The 3467' deep well for Greenfield is the deepest well sampled in the
study but does not have the highest radioactivity or hardness. The
samples collected at the 10 minute, 30 minute, 5 hour and 15 hour intervals
showed little change in the radium or o'ther chemical parameters indicating
little vertical recharge of water from other formations. The radium-226
value on all four well samples was 14 pCi/1, hardness varied from 595
to 630 mg/1 for an average of 610 mg/1, iron 1.6 mg/1 and total solids
averaged 2,160 mg/1.
Table 6 lists the concentrations and percentage removals of these per-
tinent radiological and chemical constituents through the reverse
osmosis unit.
Table 6
Radium-226, Hardness, Iron and TS Removals
Reverse Osmosis
Greenfield, Iowa
August 8, 1974
Sampling
Point
Well Supply
RO Permeator
RO Plant Eff
Overall
Ra-226
Hardness Iron Total
Percent
pCi/1 Removal mg/1
14
#1 0.35 97
0.6 96
0.6 96
610
4
29
29
Solids
Percent Percent Percent
Removal mg/1 Removal mg/1 Removal
1.6 2160
99 99
95 0.3 81 164
95 0.3 81 164
95
93
93
A very high reduction of hardness from 610 to 4 mg/1 or a percentage re-
moval of 99% was accomplished through permeator unit #1. A parallel
reduction of radium-226 from 14 to 0.35 pCi/1 or a percentage removal of
97% was accomplished through this unit. A reduction of hardness from
610 to an average 29 mg/1 and an overall hardness percentage removal of
95% was found in the combined effluent of the three permeator units.
This hardness removal is considerably greater than that normally used
in municipal softening practice. Again a high parallel reduction of
radium-226 from 14 to an average 0.6 pCi/1 or a percentage removal
of 96% was accomplished through the three units.
-------
Table 5
Radiological and Chemical Analysis
Greenfield, Iowa Water Supply
August 8, 1974
Sampl ing Point
Well #1 3467' 10 min
Well #1 3467' 30 min
Well #1 3**67 ' 5 hr
Well #1 3467' 15 hr
*RO Permeator #1 10 min
RO Permeator #1 5 hr
RO Plant Eff 30 min
RO Plant Eff Dup
RO Plant Eff 5 hr
RO Perm. #1 Reject 30 min
RO Perm. #1 Reject 5 hr
RO Perm. #3 Reject 30 min
RO Perm. #3 Reject 5 hr
^Reverse Osmosis
Gross
Alpha
pCi/l
25
23
21
30
1.0
0.4
0.9
1.3
Nil
112
86
69
77
Ra
226
pCi/l
14
14
14
14
0.3
0.4
0.7
0.6
0.5
48
38
56
48
Hard-
ness
mg/l
595
600
630
595
4
4
26
22
40
1850
1840
2070
2070
Total
Solids
mg/l
2159
2159
2150
2162
100
99
172
J62
159
6515
6470
7307
7248
Alkal inity
P
mg/l
0
0
0
0
0
0
0
0
0
0
0
0
0
T
mg/l
196
192
190
193
28
40
35
41
44
10
46
1.0
35
PH
7.
7.
7.
7.
5.
5.
5.
5.
5.
4.
5.
4.
5.
1 ron
Total
mg/l
6
6
8 1.6
7
6
25
15
4
9 0.3
75
8 4.1
15
25
Sol Ca
mg/l mg/l
170
170
1.6 160
170
1.7
1.0
6.4
5.4
0.3 6.7
480
4.1 480
550
540
Mg Na
mg/l mg/l
54
54
54 440
54
0.7
0.4
2.4
2.1
2.3 55
160
160 1300
180
180
Mn C I SO/,
mg/l mg/I mg/l
860
880
0.01 395 870
890
40
33
84
70
0.01 40 50
3000
0.01 1200 2900
3200
3000
-------
As shown in table 5 two samples for radiological and chemical analyses
were collected from the reverse osmosis permeator unit #1 and three
samples from the plant effluent containing the discharge of the three
permeator units. There appears to be little variation in the efficiency
of treatment during the early or 5 hour period of treatment. Only a
slight increase in hardness and a slight decrease in sulfate content was
noted in the plant effluent after five hours of treatment and these
values may not be significant.
The literature™ indicates that a characteristic of essentially all
reverse osmosis membranes is that rejection of divalent ions such as Ca
Mg and 804 is much greater than for the monovalent ions such as Na and
Cl. Removal of these divalent ions is in the range of 92 to 99% whereas
the removal of the monovalent items is less than 90%. Radium-226 is a
divalent ion and the high radium removals of 97 to 96% parallel the
hardness, calcium and magnesium removals.
Iron removal by the reverse osmosis unit was from a raw value of 1.6 to
0.3 mg/1 or a percentage removal of 81%. This is a lower than expected
removal. Total solids were reduced from 2,160 to 99 mg/1 in permeator
#1 and to 164 mg/1 in the combined permeator effluent for removals of
95 and 93% respectively.
While the product water from the permeators contains less than 10% of
the total solids which were in the feed, the reject stream from the
permeators contains about three times the amount of total solids in
the original feed from the deep well. Table 7 lists the operating
data for the three permeators during an operating period of 405 minutes.
Operation of the three units continued for a total operating time of
about 10 hours but samples and operating data were collected during
the shorter period.
Table 7
Reverse Osmosis Plant Operating Data
Greenfield, Iowa
August 8, 1974
Gallons Minutes Rate Percent Gallons Rate Percent
Unit Pumpage Operation gpm Product Reject gpm Reject
Permeator 20,560 405 33.4 66 7,020 17.3 34
#1
Permeator 18,206 405 32.2 72 5,210 12.7 28
#2
Permeator 17,590 405 30.8 71 5,100 12.6 29
#3
Total 56,360 405 96.5 69 17,330 42.8 31
42
-------
The flow rate of 96.5 gpm is slightly less than the design rate of 105
gpm for the three tube permeators. The percent product water or the
percent conversion of treated water produced to well water pumped was
69 percent which is within the low product recovery range for municipal
installations.
Post treatment of the product water consists of decarbonation by means
of an aerator and addition of about 40 mg/1 of soda ash to raise the
pH to the 7-8 range. Operating control of the permeator is generally
by a simple specific conductance test. In addition automatic pH control
equipment would shut down the system in the event of loss of chemical
feed in order to protect the permeators from damage.
From the standpoint of corrosivity, chemical stability as indicated by
saturation with calcium carbonate is the most widely accepted criterion
in the classification of a water as "corrosive" or "protective". A
minimum alkalinity of 50 to 100 mg/1 and a minimum of about 50 mg/1 of
calcium (expressed as Ca 003) must be present at normal temperatures
for protection of water mains by the deposition of a calcium carbonate
coating. A positive saturation index is invalid if there is not suf-
ficient alkalinity or calcium present to provide a scale forming film.
The town of Greenfield uses the reverse osmosis treated water to supple-
ment the supply of surface water supply. The reverse osmosis treated
water has a calcium content of only about 6 mg/1 or about 15 mg/1 ex-
pressed as calcium carbonate. The mixture of the treated deep well and
surface water supply contains sufficient calcium carbonate to minimize
water main corrosion by deposition of a calcium carbonate protective
coating.
A water supply utilizing reverse osmosis for desalting or radium removal
may have insufficient calcium remaining to provide a protective coating
for corrosion control and the addition of calcium ions would be necessary
for corrosion control. In some cases polyphosphate or sodium silicate
treatment might be possible. Economic losses incidental to corrosion of
water distribution systems and plumbing fixtures or the serious reduction
of carrying capacity of water mains may occur even when corrosion is
not active enough to produce red water.
Radium-226 Material Balance
Figure 11 is a schematic drawing showing the treatment units and the
radium-226 total radioacitivity at various stages in the treatment
process. Detailed radium computations for the 10 hour day are shown
in Section B in the Appendix.
Of the total 144,000 gallon well pumpage, 45,000 gallons or 31% is in
the reject water stream leaving 99,000 gallons or 69% converted to pro-
duct water pumped to the distribution system. Applying the 14 pCi/1
43
-------
Figure 11
Ra-226 Distribution in Treatment Process
Greenfield, Iowa
Reverse Osmosis Desalting Plant
August 8, 1974
Remova 1
Thru t
Unit
7.62
-7.40
0.22 by difference
Unit
if fluents
.62 uCi |
14 pCi/1
, 22 uCi 1
0.6 pC5/l
Well
144,000 gpd (Approximately
10 hours)
_ Sulfuric acid
_ Calqon
3 Reverse Osmosis
Permeators
31% Reject
Ilwaste
7.40 uCi | +•
43,uuu gpd —
43 pCi/1
69% conversion
99,000 gpd
Legend
|| Total
17-62 ud I Radioactivity
14 pCi/1 Concentration
Distribution
System
44
-------
concentration value to the well pumpage gives a radium-226 total radio-
activity of 7.62uCi in the well water. Similar calculations show a
radium-226 concentration of 43 pCi/1 and a total radioactivity of 7.40uCi
in the reject water with a remaining radium-226 concentration of 0.6
pCi/1 and a total radioactivity of 0.22 uCi in the product water to the
distribution system. It will be noted that subtracting the total radio-
activity of 7.40 uCi in the reject water from the 7.62 wCi in the well
water leaves a difference of 0.22 uCi in the product water. This latter
value was also calculated from the readium-226 concentration remaining
in the product water. An excellent material balance of radium-226
through the system was attained.
45
-------
SECTION 11
IRON AND MANGANESE REMOVAL
SECTION 11.1
PROCESS DESCRIPTION
The presence of iron and manganese, particularly in well supplies, is
objectionable primarily because the precipitation of these metals alters
the appearance of the water, turning it a turbid yellow-brown color.
In addition, the deposition of these precipitates will cause staining
of plumbing fixtures and laundry. Another condition which has been
associated with the presence of iron and manganese in water supplies
has been the growth of microorganisms in distribution systems. Accumu-
lations of microbial growths can lead to reduction of pipeline carrying
capacity, resuspension of these deposits causing high turbidities and
adverse consumer complaints of tastes and odors.
Because of the nuisances caused by relatively small concentrations of
these metals, many groundwater supplies for municipalities require
treatment for removal or control of iron and manganese. Where ion
exchange softening is employed, iron and manganese are frequently
removed prior to exchange because the precipitates formed would cause
clogging problems and would coat the exchange media or oxidize after
penetration, resulting in a loss of exchange capacity.
The presence of iron and manganese in groundwater is generally attribu-
table to the solution of rocks and minerals, chiefly oxides, sulfides,
carbonates and silicates containing these metals. The fact that man-
ganese bearing minerals are less abundant than iron bearing minerals in
part accounts for the fact that iron is found more frequently in ground
waters. The solution of iron and manganese bearing minerals is often
attributed to the action of carbon dioxide in groundwaters. The con-
centrations of iron and manganese found in solution in natural waters
are frequently limited by the solubility of their carbonates, therefore,
waters of high alkalinity often have lower iron and manganese contents
than those of low alkalinity.
The treatment processes employed in the removal or control of iron and
manganese include:
1. Precipitation and filtration
a. Aeration, detention (or sedimentation) and filtration
b. Oxidation by potassium permanganate, chlorine or
chlorine dioxide
46
-------
2. Ion Exchange
a. The manganese greensand zeolite process
In water treatment plant practice, the great majority of iron and man-
ganese removal plants employ aeration, detention (or sedimentation) and
filtration. In many instances, chlorine is added following aeration to
aid in oxidation.
In the oxidation reaction, iron and manganese are first oxidized (iron
from Fe+2 to Fe+3 and manganese from Mn+2 to Mn+4) an(j precipitated as
insoluble hydroxides or oxides. Recent studies'^ have shown that, par-
ticularly with hard waters, ferrous carbonate (FeCOs) can be expected to
precipitate and then remain unoxidized, meaning that filters in iron
removal plants may be removing ferrous carbonate rather than ferric
hydroxide. The oxidation of manganese (Mn+2 to Mn+4) by dissolved
oxygen is much slower than the oxidation of Fe+2 and is very slow at a
pH less than 9.5. Chemical oxidation of Mn+^ is generally required to
achieve precipitation of MnC>2 in pH ranges common to waterworks practice.
Potassium permanganate will oxidize the manganous ion to manganese
dioxide rapidly (within 5 minutes) over a broad pH range.
The removal or iron and manganese on continuously regenerated permanganate
greensand filters is practiced by continuously adding the potassium
permanganate to the water prior to passage through a bed of zeolite
(greensand exchange media. The permanganate oxidizes the iron and man-
ganese so that the exchange medium becomes coated with oxidation products.
The hydrous oxides of iron and manganese deposited on the exchange
medium have a large sorption capacity for Fe+2 and Mn+2.
Sorption reportedly plays a significant role in the removal of iron and
manganese from solution. Precipitates of hydrous oxides of Fe+ and
manganese dioxide both have high sorption capacities for Fe+2 and Mn+2.
This phenomenon may account for the removal of iron and manganese on
contact filters as well as within filters where the filter medium is
coated with precipitate. A period of "aging" is required for the depo-
sition of the precipitate to take place.
Sedimentation is rarely specifically provided unless the concentrations
of iron and manganese in the raw water is quite high (>10 mg/1). Gen-
erally, little sedimentation occurs in detention tanks and instead are
considered to be quiescent reaction basins.
SPECIFIC PROCESSES
Iron and manganese removal is utilized in some form of pretreatment for
the four ion exchange softening plants and as the only removal process
at two other plants selected for the study. This information is sum-
marized in Table 8.
47
-------
TABLE 8
Iron and Manganese Removal Processes
Municipality
Detention
Iron & Manganese Removal Only
Adair
Stuart
140 min.
24 hour
Ion Exchange Pretreatment
Eldon
Estherville
Grinnell
Holstein
7min.
None
24 hour
2 hour
Type Filter
Pressure
Pressure
Pressure
Gravity
None
Pressure
Media
Greensand
Anthrafilt
Anthrafilt
Anthrafilt
Anthrafilt
48
-------
SECTION 11.2
ADAIR
BACKGROUND INFORMATION
Adair is located on the northern border of Adair County in southwest
Iowa with the northern portion of the City lying in Guthrie County.
Both counties have experienced population outmigration due to advances
in agriculture and farm consolidation. Adair had experienced signifi-
cant population decreases until the 1960-1970 period when construction
of the adjacent interstate highway stimulated the development of light
industry. The 1970 population is 750 with projected moderate future
population increases.
EXISTING WATER FACILITIES
Adair obtains its water supply from two deep wells called the "old dry
well" or Well No. 1 and the "Jordan well" or Well No. 3. The wells are
described as follows:
WELL WATER SUPPLY - ADAIR
Well No.
1
3
Year
Drilled
1941
1967
Depth
Feet
1,728
2,700
Capacity
60
200
Aquifer
Silurian-Devonian
Jordan
Figure 12 is a flow diagram of the Adair aeration and manganese greensand
iron removal pressure filter. Normally, the Jordan well only is used and
is pumped at a 200 gpm rate to a forced draft aerator which discharges to
a 17,000 gallon detention tank. High service pumps with capacities of 115
gpm pump the aerated water after continuous potassium permanganate dosage
through two manganese greensand iron removal filters to the distribution
system.
MANGANESE GREENSAND PERFORMANCE
Table 9 is a tabulation of the radiological and chemical analysis per-
formed on samples collected from the deep well furnishing the principal
source of raw water supply for the town of Adair and from the various
stages in the aeration detention and manganese greensand filtration, A
second survey was conducted when the first survey indicated extremely low
removal of radium and it was determined grossly inadequate amounts of
potassium permanganate regenerant were being added to the filter. Addi-
tional mineral analyses are shown in Appendix. Percentage removals of
radium-226 and iron from the May 13, 1975, survey are also shown on plant
flow diagram, Figure 12.
49
-------
10' x 34'
x 6.4'
O
Figure 12
Flow Diagram
Adair, Iowa - Population 750 (1970)
Greensand Iron Removal Plant
Well No 3
Depth 2700'
Capacity 200 gpm
Parameter and
Removal Efficiency
Ra-226 Iron
pCi/1 mg/1
May 13, 1975
-Well
Forced draft aerator
30" diam 800 cfm blower
Detention Tank
Capacity 16,800 gal
Detention 140 min @ 100 gpm
13
1.1
13
1.2
Settled
High service pump 115 gpm
—Clo
2 Greensand Filters-Vertical
V diameter 48" media depth
Area 12.57 sqft each
Filter rate 4 gpm/sqft
J Backwash 2120 gal/unit @ 14 min
-Effluent
Overall Removal
8
38%
0.02
98%
•System
7-5 0.32
Distribution System
50
-------
Table 9
Radiological and Chemical Analysis
Adair, Iowa Water Supply
September 16-18, 1974*
Gross Ra Hard- Total Alkalinity
I ron
Alpha 226 ness
Sampling Point pCi/1 pCi/1 mg/1
Well #3 2700' 1/2 hr
Well #3 2700' 6 hr
Green Sand Filter Inf 6 hr
Green Sand Filter Inf 6 hr
Green Sand Filter Eff 1 hr
Green Sand Filter Eff 25000
Green Sand Filter Eff 50%
Green Sand Filter Eff 50% Dup
Green Sand Filter BW 2 min
Green Sand Filter BW 4 min
Green Sand Filter BW 8 min
Distribution System
Well #3 8 hr Comp
Fi Iter Inf 8 hr Comp
Fi Iter Eff 8 hr Comp
Fi Iter BW 5 "<" ComP
14
16
9.3
6.8
13
10
11
16
330
92
89
11
16
16
14
200
6.9
6.3
6.9
6.9
6.7
7.7
6.7
6.0
250
84
65
7.5
13
13
8.0
190
710
710
700
710
680
680
680
815
Solids
mg/1
1921
1880
1896
2057
May 12,
1890
1890
1900
2040
P
mg/1
0
0
0
0
0
0
0
0
1975
0
0
0
0
T
mg/1
240
164
159
161
157
158
158
156
163
178
169
pH Total
mg/1
7.4
7-5
7.45
7.45
7.45
7.45
7.5
7.45
7.4
7.4
7.45
7.4
0.41
0.58
0.01
0.10
0.77
0.17
0.02
0.02
64
23
20
0.32
Sol
mg/1
0.05
0.04
0.01
0.01
0.05
0.01
0.01
0.01
Ca Mg Na Mn
mg/1 mg/1 mg/1 mg/1
'0.01
180 70 330 0.01
*0.01
170 70 330 «-0.01
<-0.01
180 66 330 0.01
"0.01
'0.01
170 70 330 3-1
1.0
0.81
•-0.01
Cl SOI)
mg/1 mg/1
330 780
360 760
350 760
370 770
Survey
164
164
162
200
7.6
8.0
7.8
7.75
1.1
1.2
0.02
59
0.01
0.01
0.04
3-6
*lron caps used on sample collection bottles on this
survey and some iron results may be in error.
In addition there may have been a mixup in bottle numbers
-------
The second survey was undertaken during May, 1975, to determine removals with
a properly regenerated manganese greensand filter. Iron removals were checked
following an initial regeneration period and an increased theoretical dosage
for continuous regeneration. During an inspection of the two filters it was
discovered that one filter was completely caked with a hole in the supporting
gravel over the underdrain resulting in no backwashing of the media or
filtration through the media. Figure 13 shows one of the Adair greensand
filters.
Figure 13
Adair Greensand Filter
Following an attempt to break up the caked greensand it was discovered that
upon filtration the media was passing out the effluent and the unit was shut
down for future repairs. All flow was then passed through a single filter at
a filtering rate of 8 -9 gpm/sq. ft. during the second survey.
Composite samples collected from the well and greensand filter influent and
effluent are shown in Table 9. Field iron determinations were made at time of
compositing to insure reasonably good iron removal was taking place.
WELLS
September 16-18, 1974
During the early survey, samples collected from the well at 30 minute and
6 hour intervals showed a slight decrease in radium-226 activity from 6.9 to
6.3 pCi/1 after the longer pumping period as shown in Table 9. At the end of
the longer pumping period hardness in the well water was 710 mg/1, total
solids 1921 mg/1, chlorides 330 mg/1, total iron o.51 mg/1, and manganese
0.01 mg/1. Table 10 lists the concentrations and percentage removals of these
pertinent radium and chemical constituents through the iron removal units
52
-------
May 13, 1975
A well composite collected over a 6 hour period on this date showed a
marked increase in radium-226 content to 13 pCi/1 when compared with
the 6.9 and 6.3 pCi/1 concentrations on the original survey. No valid
reason can be given for the increase except for changes in pumping rates
as compared with the earlier survey. The deep well was shut down for a
three day period a week before the second survey due to a pump motor
failure. Well pumpage rate was in the 150,000 gpd rate at the time of
the second survey due to an undetected main leak as compared with a
100,000 gpd rate during the earlier survey. These pumping rates may
have affected the vertical recharge of the well formation.
TABLE 10
Radiun-226 and Iron Removals
Continuously Regenerated Greensand Filter
Adair, Iowa
Ra-226 Total Iron
Percent Percent
Sampling Point pCi/1 Removal mg/1 Removal
September 16. 1974
Well Supply 6.6 - 0.50
Detention Tank Effluent 6.9 - 0.10 80
Greensand Filter Effluent 6.3 - 0.07 43
Overall Removal 5 32
System 7.5 0.32
May 13, 1975
Well Supply 13 - 1.1
Detention Tank Effluent 13 0 1.2
Greensand Filter Effluent 8 38 0.02 98
Overall Removal 38 98
Detention Tank
September 16-18, 1974
Iron removal analyses are not considered reliable due to possible collec-
tion errors and iron caps on the sample bottles.
May 13, 1975
Determinations made on composite samples during the May survey indicated
no removal of iron or radium-226 through the detention tank.
53
-------
MANAGESE GREENSAND FILTER
September 16, 1974
Radiological and chemical analyses were collected at intervals through the
usual greensand filter run as indicated in Table 10. Radium showed some
variations and a representative average indicated a radium-226 reduction
from 6.6 pCi/1 in the well supply to 6.3 pCi/1 for a reduction of only 5%.
Iron values dropped to an average range of 0.07 mg/1.
May 13, 1975
Total iron values on the May Survey were reduced from 1.1 mg/1 in the compos-
ite of the greensand filter effluent for an excellent overall removal of
98 percent. Likewise, the radium-226 content in the effluent was reduced to
8 pCi/1 from 13 pCi/1 in the well water for an overall radium reduction of
38 percent. Therefore, it appears that proper potassium permanganate dosage
of the manganese greensand filter greatly improved the iron oxidation and
removal with a concurrent improvement in radium removal. This removal was
being accomplished with a single greensand filter operating at double the
normal filtering rate.
After a week of continuous regeneration of the manganese greesand filter at
the theoretical potassium permanganate dosage, the filter effluent composite
showed a manganese content of 0.04 mg/1. A faint pink color due to potassium
permanganate was evident in some of the individual composite filter effluent
samples collected during the day. The concentration of the potassium
permanganate feed solution was reduced somewhat by dilution and the pink
color disappeared n the filter effluent samples.
RADIUM-226 MATERIAL BALANCE
Figures 14 and 15 are scheow.tic drawings showing the water treatment units
and the radium-226 total radioactivity and concentrations at various stages
in the treatment process from data on the two surveys conducted in September,
1974, and May,1975. Detailed computations are included in the Appendix B.
September 18, 1974
Applying the 6.6 pCi/1 radium concentration value to the well pumpage over a
two-day pumpage period gives a total radium-226 radioactivity of 5.3pCi in
the well water supplied to the filter. There was no reduction following
aeration and detention.
The radium-226 total radioactivity of 1.2 uCi in the manganese greensand
filter was the activity accumulated in the filter during the two-day filter
run and was calculated by using the composite pCi/1 concentration in
the filter backwash. This 1.2 uCi value in the greensand filter effluent.
Thus, there was a fair meterial balance of radium-226 through the treatment
units.
54
-------
Figure Tf
Ra-226 Distribution in Treatment Process
Ada Ir, Iowa
Greensand Iron Removal Plant
September 18,131k
Remova1
Thru
Units
uCi
5.3
5-3
Legend
5-3 uCi
Unit
Effluents
uCi
5-3 uCi
6.6 pCi/1
Well 2 day pumping period
212,000 gal
Aerator
Detention Tank
min detention
KMn 0,
Greensand
Filters
|5.0 uCi
Filter
Backwash
1.2 uCi 1
$8-167 pCi/1
6.3 pCi/1
Total
Radioactivity
6.6 pCi/1 Concentration
Distribution
System
55
-------
Remova1
Thru
Unit
uCi
2.72
2.72
Figure 15
Ra-226 Distribution in Treatment Process
Adair, Iowa
Greensand Iron Removal Plant
May 13, 1975
-0.75
1.97
by difference
Legend
Unit
Effluents
uCi
2.72uCir
13PCI/1
Total
Radioactivi ty
Well 8 hour pumping 55,200 gal
Aerator
Detention Tank
min detention
KMn 04
Greensand
Fi Iters
Filter
Backwash
"| 0.75 uC?I
200 pCi/1
Di stribution
System
13 pCi/1 Concentration
56
-------
May 13, 1975
The radium-226 concentration in the well water nearly doubled to a value
of 13 pCi/1 and there was a substantial reduction of radium concentration
through the manganese greensand filter which was receiving proper potas-
sium permanganate dosage during this survey.
The 13 pCi/1 concentration applied to the eight hour well pumpage period
gives a total radium-226 radioactivity of 2.72 uCi which is also the
total radioactivity in the detention tank effluent discharging to the
greensand filter.
A total radium-226 radioactivity of 2.05 uCi was accumulated in the fil-
ter backwash during the filter run of 150,470 gallons before backwash.
Only 55,200 gallons were filtered during the 8 hour sampling period for
the other plant units and the 2.05 uCi was proportioned to give a 0.75
uCi total radioactivity accumulated in the filter backwash during the
shorter period. This radioactivity removed by the backwash when sub-
tracted from the greensand filter effluent radioactivity gives a calcu-
lated radium-226 radioactivity of 1.97 uCi compared with the value of
1.67 uCi in the greensand filter effluent. This is a fair material
balance through the treatment system.
57
-------
SECTION 11.3
STUART
BACKGROUND INFORMATION
Stuart is located on the northeastern border of Adair County in southwest
Iowa with the northern portion of the town located in Guthrie County.
Both counties have experienced population outmigration due to farm
consolidation and, as a result, the Town of Stuart has also had a signifi-
cant decrease to a 1970 population of 1,354 persons.
EXISTING WATER FACILITIES
Stuart presently derives its public water supply from a 2,801 foot deep
Jordan formation well constructed in 1962. Figure 16 is a flow diagram
of the Stuart iron removal plant. The 300 gpm well transfers water to a
forced draft aerator location on top of the 150,000 gallon concrete
surface detention and settling tank. Transfer pumps of 300 gpm capacity
pump the settled water from the surface storage reservoir through a
four-cell horizontal pressure iron removal filter provided with anthracite
media. High service pumps of 300 gpm capacity pump from a 150,000 gallon
concrete surface clearwell to the distribution system. The iron removal
filters are shown in Figure 17.
Figure 17
Stuart Iron Removal Filters
58
-------
Figure 16
Flow Diagram
Stuart, Iowa - Population 1,354 (1970)
Pressure Filter - Iron Removal Plant
Wei 1 No 3 Parameter and
Depth 2801' Removal Efficiency
Capacity 300 gpm Ra-226 Iron
pCi/1 mg/1
-Wei 1 16
Induced draft aerator
Surface reservoir - 150,000 gal capacity
Detention 27 hrs @ 300 gpm
Reservoir 14 1.0
Transfer pump 300 gpm 13%
Anthracite pressure filter
4 Cell 7.5' diam 14' long
Total area 118 sqft 24" Media depth
Service rate 300 gpm @ 2.5 gpm/sqft
Capacity 432,000 gpd
Backwash rate 300 gpm @ 10.2 gpm/sqft
12 min @ 300 gpm = 3600 gal each
• Effluent 12 0.03
14% 97.0%
Clearwell - 150,000 gal capacity
Overall Removal 25% 972
High Service Pumps 2 - 300 gpm
•-System 12 0.22
Distribution System
59
-------
AERATION, SEDIMENTATION AND FILTRATION PERFORMANCE
Table 11 is a tabulation of the radiological and chemical analyses
performed on samples collected from the 2,801 foot #3 deep well furnishing
the raw water supply for the town of Stuart and from the various stages
in the aeration and iron removal filtration process. Additional mineral
analysis results _are shown in Appendix A. Percentage removals of_
radium-226 and iron are also shown on the plant flow diagram, Figure 16.
Well
The 2,801 foot deep #3 well was pumped at a 300 gpm rate. The well
sample collected after a 5-hour pumping period showed a radium-226 content
of 16 pCi/1 which was the second highest radium concentration in the
study. Hardness in the well water was 640 mg/1, total solids 1,770 mg/1
and total iron 0.94 mg/1.
The radium-226 content of 16 pCi/1 in the well water was reduced to 14
pCi/1 after passage through the 27-hour detention tank for a removal of
13 percent. No reduction in iron content concurred during aeration and
settling in the ground storage tank with a theoretical 24-hour detention
period.
Radium-226 was further reduced in the iron removal filter from a value of
14 to 12 pCi/1 for a reduction of 14 percent through this unit and an
overall reduction of 25 percent of radium-226 through aeration, settling
and filtration. The iron content of 0.94 mg/1 in the raw water was
reduced by the same treatment process to 0.03 mg/1 for an overall iron
removal of 97 percent. The 0.22 mg/1 of iron in the distribution system
sample may indicate iron pickup from the water mains due to a slightly
aggressive water.
There were no significant changes in other chemical parameters during the
aeration, detention and filtration. Iron removal efficiency remained
the same (97 percent) during the two week filter run.
These results indicate that some amount of radium-226 concentration is
removed during the aeration, detention and filtration process. The
overall radium removal of 25 percent is low compared with the 97 percent
iron removal. The manner of radium removal on the iron filter is
possibly adsorption or catalytic action by the oxijation products
deposited on the filter media.
60
-------
Table 11
Radiological and Chemical Analysis
Stuart, Iowa Water Supply
October 22,
Total
Gross Ra Hard- Dis Ajkal ini ty I ron
Alpha 226 ness Solids P T pH Total Sol Ca Mg Na Mn Cl SO/,
_ Sampling Point pCi/1 pCi/1 mg/1 mg/1 mg/1 mg/1 _ mg/1 mg/1 mg/1 mg/1 mg/1 mg/1 mg/1 mg/1
Well #32801' 5 hr 32 16 6*»0 1770 0 182 7-6 0.9*» 0.92* 150 62 310 0.01 2*»0 780
Detention Tank 5 hr 2k ^k 6kO 1760 0 182 7-9 1-0 1.0 150 62 300 0.01 260 790
Detention Tank 20 hr 16 13 6^0 1780 0 182 7-9 1.0 1.0 150 62 310 0.01 2^0 780
Iron Filter Eff 2 hr 15 12 6*tO 17&0 0 171* 7.6 0.03 0.03 150 62 300 0.01 250 780
Iron Filter Eff 2 wk \k 12 630 1760 0 171* 7.6 0.03 0.03 150 61 310 <0.01 250 780
Iron Filter Backwash 2 min 3^0 230 630 2178 0 186 7.6 120 120 160 62 310 0.23 260 790
Iron Filter Backwash 12 min 180 120 630 192*4 0 178 7.6 93 160 62 310 0.67 250 780
Distribution System 23 12 620 17^0 0 170 7.6 0.22 0.22 150 62 310 0.01 250 780
-------
The iron removal filter backwash accumulated high concentrations of
radioactivity and iron during the two week filter run. Radium-226 con-
centration increased to values of 230 and 120 pCi/1 at 2 minute and 12
minute intervals respectively during the backwash period. Likewise,
the iron concentrations increased to 120 and 93 mg/1 at these same in-
tervals during the backwash period.
RADIUM-226 MATERIAL BALANCE
Figure 18 is a schematic drawing showing the water treatment units and
the radium-226 total radioactivity and concentrations at various stages
in the treatment process. The detailed computations are included in
the Appendix B.
Applying the 16 pCi/1 radium concentration value to the well pumpage of
1.97 million gallons during the two week iron filter run gives a total
radium-226 radioactivity of 119 yCi in the well water pumped. The
radium-226 total radioactivity calculated from the 14 pCi/1 concentration
in the detention tank effluent was 104 yCi for a reduction of 13 percent.
The radium-226 total radioactivity of 7.6 yCi in the iron removal filter
backwash was the radioactivity accumulated in the filter during the 14
day filter run and was calculated by using the composite 120 pCi/1 con-
centration in the filter backwash. This 7.6 yCi/1 radioactivity value
subtracted from the detention tank activity value should have equalled
the activity in the iron removal filter effluent. The calculated radium-
226 radioactivity value of 96 yCi/1 compares with an activity value of
89 yCi in the filter effluent. Thus there was a fair material balance
of radium-226 through the treatment units.
62
-------
Figure 18
Ra-226 Distribution in Treatment Process
Stuart, Iowa
Aeration and Iron Removal Filter Plant
Remova1
Thru
Unit
yCi
119
104
-7.6
by difference
Unit
Effluents
uCi
1119 uCi |
1 1
16 pCi/1
Well 14 day pumping period
Before backwash
1,970,000 gallons
Average daily pumpage
140,000 gpd
Aerator
Detention Tank
Detention 10 hrs §
300 gpm
104 uCi f
14, pCi/1
I
09 uC i |
1 1
4- Iron Removal
Filters
I
Filter J 7 6 uCi 1
(after 14 days) 120 pCi/1
12 pCi/1
J-eaend
C'
Radioactivity
16 pCi/1 Concentration
Distribution
System
63
-------
SECTION 12
SODIUM CATION EXCHANGE
SECTION 12.1
PROCESS DESCRIPTION
The sodium cation exchange softening process is employed by four of the
municipalities in the study. It should be noted that iron removal is
employed as a part of pretreatment by all of the ion exchange plants
studied.
Water softening by the sodium cation exchange (zeolite) process depends
upon the ability of certain soluble substances to exchange cations with
other cations dissolved in water. When hard water is passed through a
sodium cation exchanger, the calcium and magnesium in the hard water
is replaced by sodium in the exchange medium. Because the reaction is
reversible, after all of the readily replaceable sodium has been ex-
changed for calcium and magnesium from the hard water, the "exhausted"
cation exchange medium can be regenerated with a solution of sodium
chloride. In the regeneration process, the calcium and magnesium of
the exhausted cation exchanger are replaced with a fresh supply of
sodium from the regenerating brine solution. Then after washing to
free it from the calcium and magnesium cations and excess salt the re-
generated exchanger is ready to soften a new supply of hard water.
Using the symbol Z for the complex zeolite radical
and regeneration reactions are shown in Figure 19.
22
the softening
Figure 19
SODIUM CATION ION EXCHANGER REACTIONS
Softening
((HC03)2
Ca (S04
Mg (C12
Soluble
Regeneration
Ca(z
Mg(
Insoluble
Na0Z
Insoluble
2Na Cl
Soluble
Ca(z H
Mg(
Insoluble
Na2
Na2Z
Insoluble
The symbol Z represents the zeolite or ion exchange
medium radical.
((HC03)2
Soluble
(To system)
Ca(Cl2
Mg(
Soluble
(To waste)
64
-------
Radium-226 is a divalent cation which is also removed in the exchange
process.
The calcium bicarbonates are converted into sodium bicarbonate which when
heated in a water heater breaks down into sodium carbonate and strongly
corrosive free carbon dioxide gas. Sodium cation exchange softened water,
therefore, is corrosive and pH adjustment for stabilization is accomplished
by addition of an alkali.
The use of the term Zeolite has been loosely applied to all ion exchange
materials which have been used for water softening. They have included
greensand, bentonitic clay, synthetic gel-type mineral, sulfonated coal and
the synthetic organic resins. Only the naturally occurring New Jersey
greensand and the synthetic polystyrene resins will be considered in this
discussion.
Natural greensand (glauconite) is found principally in a commercial deposit
in New Jersey. It has an exchange capacity of 3,000 grains of hardness per
cubic foot of media which is only a tenth of the capacity of the newer
synthetic polystyrene resins. It has the feature of removing ferrous iron
and manganese ions during softening and is also commonly used for removal of
iron and manganese by regeneration with potassium permanganate.
Practically all of the present ion exchange media used in softening are the
polystyrene resins which, were patented by D'Alelio in 1945. These resins
are produced by the polymerization of styrene monomer with divinyl benzene
(DVB) and the resulting resin particle beads are made ion exchange active by
sulfonation.
TABLE 12
Operating Characteristics of Polystyrene Ion Exchange Resin23
Range
Operating exchange capacity kgr/cu ft 20-35
Recommended bed depth, inches 24-48
Softening flow rate, gpm/sq ft 4-8
Softening flow rate, gpm/cu ft 2-6
Backwash flow rate, gpm/sq ft 5- 6
Salt dosage, Ibs/cu ft 5-20
Brine concentrations, % 8-16
Regeneration brine contact time, min 25-45
Rinse flow rate, gpm/cu ft
Slow 1- 2
Fast 3-5
Rinse requirements gal/cu ft 20-40
Conformance with these operating conditions or other design parameters was
determined to indicate whether proper performance and efficiency of the
softener unit could be expected at time of sampling. Some operating
65
-------
difficulties and unusual conditions were encountered during some of the study
sampling periods but it is believed final results were not seriously affected.
Since the whole depth of the softener unit is involved in the ion exchange, a
rate of flow in terms of unit volume is more significant. On completion of
the softening cycle, the softener is backwashed in an upflow direction to
remove particulates from the top of the bed, loosen the resin and regrade to
assist in regeneration.
All ion exchange softeners in the study were of the pressure type in vertical
steel shells. In regenerating the pressure softener, brine in a downflow
direction is introduced to the bed at a controlled rate generally through a
distribution system set immediately above the exchanger media surface. For
the sodium cycle, the exchange capacity of the polystyrene resin for the
usual, most economical operating range is from 20 to 27 kilograins of hardness
per cubic foot expressed as CaC03- Low dosages of salt in the 6-10 Ib/cu ft
range result in the most efficient regeneration, provided there is no short
circuiting. There is also an optimum 10-15 percent concentration of brine to
produce the maximum exchange capacity. For this brine concentration, a flow
rate of 1-2 gpm/cu ft is necessary to secure adequate contact time of the
brine with the exchanger media. Rinse water is then applied until the
chloride and hardness have been reduced to a level where the unit can be
returned to service. The water used to rinse the exchanger is the raw water
being treated by the exchanger. It has been determined that 20-40 gallons
of water per cubic foot of resin will be needed for rinsing.
After completion of the regeneration cycle, the softener is returned to
service and the raw hard water is passed through the unit until a prede-
termined hardness breakthrough appears in the effluent. In most municipal
systems, the softened water is blended with unsoftened water to produce an
intermediate hardness effluent and provide a calcium carbonate content for
deposition of a protective calcium coating in the water mains. There appear
to be no deleterious effects from almost complete exhaustion of the resins.
Blending of hard water with the softened effluent is generally accomplished
by means of a hard water bypass proportioning system.
The composition of the influent water may have an effect on the capacity and
hardness leakage of the resin. Hardness alone in the influent water has
little effect on the capacity of the resin. As the sodium content of the
effluent water increases, competition develops between the sodium and hardness
ions for active sites on the resin and there will be a decrease in capacity
and an increase in hardness leakage of the softener.
Iron in the softener feedwater, in either the precipitated or solution form,
will seriously affect the exchange capacity. Iron in the ferrous (unoxidized)
form will be removed by ion exchange but some iron ions deep within the
structure of the resin particle may be oxidized to a stable nonexchangeable
form. Most iron oxidized prior to softening will be filtered out and removed
during backwashing but there may be serious loss in exchange capacity.
66
-------
Manganese in natural waters will also cause resin fouling and loss in
exchange capacity. Usually manganese is present in lower concentra-
tions and therefore may not be as troublesome as iron.
Iron, manganese and other chemical fouling can be minimized in the
operation of municipal softeners by pretreating the water. Methods
which may be used include; (1) aeration and filtration, (2) chemical
coagulation or oxidation and filtration, (3) chlorination and filtra-
tion or (4) use of manganese greensand filters without pretreatment.
In many of the smaller towns the zeolite regeneration procedure is
made completely automatic with the addition of an automatic multiport
valve. This valve is rotated through the operating positions of ser-
vice, backwash, regeneration and rinsing by an eletric motor and a
system of electrical controls.
67
-------
SECTION 12.2
ELDON
BACKGROUND DATA
Eldon is located in Wapello County in south central Iowa. Eldon has a
population of 1,319 persons and is primarily agriculture service oriented,
EXISTING WATER FACILITIES
Eldon presently derives its public water supply from a 1,901 foot deep
Jordan well drilled in 1961. Figure 20 is a flow diagram of the Eldon
iron removal and zeolite softening plant. Raw water from the deep well
No. 8 is pumped by a 200 gpm capacity pump through a forced draft
aerator to a 1,500 gal. detention tank. High service pumps then
discharge to a four-cell anthracite pressure iron removal filter to
two vertical zeolite softeners (figure 21) and to the system.
Unsoftened water is added to the softened ion exchange softener effluent
to provide sufficient calcium carbonate for deposition of a protective
coating on the water mains.
Iron filter backwash and softener backwash and spent brine rinse are
discharged to a storm sewer with eventual discharge to the Des Moines
River.
Figure 21
Eldon Ion Exchange Softeners
IRON FILTER AND ION EXCHANGE PERFORMANCE
Table 13 is a tabulation of the radiological and chemical analyses per-
formed on samples collected from the deep well furnishing the raw water
68
-------
Figure 20
Flow Diagram
Eldon, Iowa Population 1319 (1970)
Pressure Iron Removal Filter and Zeolite Softener Plant
Parameter and
Well No 8. Removal Efficiency
Depth 1901 Ra-226 Hardness Iron
Capacity 200 gpm pCi/1 mg/1 mg/1
Well j,g 375 2.0
Forced draft aerator
Detention Tank
1500 gal capacity
Detention 7 min @ 200 gpm
High service pump 200 gpm
Anthrafilt pressure filter
A - Cell 8' diam IV length
Total area 112 sqft Unit 28 sqft
Service rate 200 gpm 1.8 gpm/sqft
Backwash rate 250 gpm 9-0 gpm/sqft
Iron Filter Effluent ^3 360 0.3
12.2% 85%
Zeolite softeners - Vertical
2 Cell 72" diam 9' height
Unit area - 28 sqft ^5" media
Unit Volume 107 cuft
Unit Capacity 106,000 gal
Service rate 75 gpm 2.8 gpm/sqft
Backwash rate 90 gpm 3.2 gpm/sqft
Softener Effluent 1.9 10 0.05
Bypass 96% 97% 83%
Overall Removal 96% 97% 98%
System 8.6 136 0.06
Distribution System
69
-------
Table 13
Radiological and Chemical Analysis
El don, Iowa Water Supply
September 13, 1974
Gross Ra Hard- Total Alkalinity
I ron
Alpha 226
Sampling Point pCi/1 pCi/1
Well #8 1901' 30 min
Well #8 1901 ' 6 hr
Iron Filter Eff 1 hr
Iron Filter Eff 12 hr
'^Softener #1 Eff 1 hr
Softener #1 Eff 20,000 gal
Softener #1 Eff 40,000 gal
Softener #1 Eff 101,000 gal
Iron Filter Backwash 2 min
Iron Filter Bakcwash 6 min
Softener #1 Backwash 2 min
Softener #1 Backwash 10 min
Softener #1 Brine Rinse 10 min
Softener #1 Brine Rinse 20 min
Softener #1 Brine Rinse 30 min
Softener #1 Brine Rinse 40 min
Distribution System
95
53
67
74
7
6.2
5.6
11
15^0
1270
81
V
670
3700
4000
1800
22
48
50
42
44
1-9
2.5
1.3
1.8
1027
254
42
18
'too
2800
3500
1300
8.6
ness Sol ids P
mg/1 mg/1 mg/1
350
400
340
380
12
14
8
6
370
260
20k
7k
5150
21300
27000
10800
136
1243
1228 0
1245
1218 0
1123
1295
1350 0
1260
1703 0
1280
1258
1264
18420
73178
88372 o
55370
1373
T pH Total Sol
mg/1 mg/1 mg/1
7.5
252 7.5
7.75
380 7.85
7.9
7.9
241 8.0
7.65
246 7.6
7.6
7.5
7.55
6.9
6.4
1580 6.4
6.6
8.25
2.0
1.9 1.9
0.10
0.51 0.51
0.07
0.80
0.11 0.11
0.01
230 230
61
7.8
7.2
0.18
0.30
0.54
0.40
0.06
Ca
mg/1
82
82
82
83
3.5
2.9
2.3
1.3
94
85
47
14
1200
5000
6000
2800
51
Mg
mg/1
36
37
37
37
1.5
1.4
0.9
0.6
38
37
24
8.6
830
2600
2600
1100
23
Na Mn Cl
mg/1 mg/1 mg/1
270
280 0
260
280<0
420
430
430 o
410
280 0
260
330
380
3000
9800
14800 0
10400
420
160
.01 160
160
.01 160
180
180
.01 160
160
.86 170
160
160
160
8500
32000
.2 41000
24000
260
SOJ,
mg/1
490
490
500
500
1100
Iron caps used on sample collection bottles
and some iron results may be in error
-------
supply, and the various stages in treatment to indicate changes in other
parameters. Additional mineral analyses are shown in Appendix A.
Percentage removals of radium-226, iron and hardness are also shown
on Figure 20.
Well
The 1,901 foot deep Jordan well pumped at a 200 gpm rate serving as the
raw water supply has the highest radium content of the well samples in
the study. Well samples collected at 30 minute and 6 hour pumping per-
iods showed radium-226 values of 48 and 50 pCi/1 respectively. Other
chemical parameters showed little or no change during the pumping period.
The well water hardness and sulfates averaged 375 mg/1 and 160 mg/1
respectively.
Iron Removal Filter
No samples were collected of the detention tank effluent because of the
short seven minute detention time. The average radium-226 and iron con-
centrations of 49 pCi/1 and 2.0 mg/1 were reduced by passage through the
iron removal filters to 43 pCi/1 and 0.3 mg/1 respectively. These values
indicate radium and iron removals of 12 percent and 85% respectively
through the iron removal filter.
Ion Exchange
Radiological and chemical analyses shown in Table 13 were collected at
20,000, 40,000 and 101,000 gallon intervals through the softening cycle.
The softener did not reach the point of exhaustion at 101,000 gallons
since it was believed at the time of the survey the design capacity was
a lesser quantity.. Additional samples could not be collected from the
second softener due to lack of a sampling petcock.
Radium-226
Figure 20 shows that radium-226 concentrations were reduced from an
average of 43 pCi/1 to an average of 1.9 pCi/1 following ion exchange
for a removal of 96%. The maximum reduction was down to a radium-226
concentration of 1.3 pCi/1 at 40,000 gallons through the softening
cycle. Hardness removal was also near the maximum at this point.
Hardness
Total hardness was reduced from an average hardness of 375 mg/1 to an
average hardness of 10 mg/1 by passage through the ion exchange softener
for an average hardness removal of 97%. Hardness values during the
softening cycle ranged from 6 to 14 mg/1.
Calcium and magnesium ions were reduced by the cation exchanger from
average raw water values of 82 and 37 mg/1 to average softened values
of less than 4 and 1.3 mg/1 respectively. Sodium increased from a raw
water value of 270 mg/1 to an average of 430 mg/1 in the softened water.
No other significant changes occurred in other chemical parameters.
71
-------
ION EXCHANGE REGENERATION
Samples for radiological and chemical analyses were collected from
softener discharges at various stages of the backwash, brine and rinse
cycles. These values are shown in the data table 13. Table 14 in-
cludes the regeneration and water usage data for the complete cycle.
TABLE 14
Regeneration & Water Use Data
Pumping Water
Time Rate Quantity
22.4 hrs 75 gpm 101,000 gal
22 min 90 gpm 2,000 gal
13 min 32 gpm 420 gal
110 min 60 gpm 6,600 gal
Backwash
The ion exchange backwash was sampled at the two minute and 10 minute
intervals during the backwash period of 22 minutes. The radium-226
content showed no increase during the backwash indicating no radium
attached to or absorbed by the slight amount of suspended solids. The
softener had not yet reached the exhaustion point at the time of back-
wash. An increase in iron content to 7.8 and 7.2 mg/1 was noted in
the backwash but the washwater was clear and the iron was not noticeable
by visual means.
Brine Cycle
Saturated brine is pumped from a brine storage tank by an ejector
with a capacity of approximately 30 gpm. During the downward brine
cycle salometer degree readings were taken continuously to determine
when the readings increased indicating chlorides of calcium and
magnesium and the excess regenerant were passing to waste from the
softener. Salometer readings were taken at five minute intervals and
four samples for radiological and chemical analyses were collected at
ten minute intervals to indicate changes during the brine and rinse
cycle.
Figure 22 is a graph of the salometer degree readings (includes other
ions than NaCl), hardness and radium-226 determinations on samples col-
lected from the waste water during the brine-rinse cycle. Radium-226
concentrations in the brine rinse increased to a maximum of 3,500 pCi/1,
hardness increased to 27,000 mg/1 and the salometer degree reading in-
creased to 24 percent. The total solids increased to a maximum of
88,400 mg/1, calcium to 6,000 mg/1, magnesium to 2,600 mg/1, sodium to
14,800 mg/1 and chlorides to 41,000 mg/1.
72
-------
FIGURE 22
Eldon, Iowa
September 13, 1974
No. 1 Zeolite Softener Brine & Rinse Cycle
\o
CM r-l
CM ^
1 -H
a u
dl D
Hardness
mg/1 as CaC03
Salometer
Degrees
BW 12:00 12
22 min
90 gpm
1,980 gal
Backwash
BW rate
.2 gpm/sq.ft.
4 000 -
3 000 -
2 000
1 000
Q
60 000
AH nnn -
20,000
10,000 -
n
30
20
10 -
1:10 12:2(
13 min
32 gpm
416 gal
Brine
y
/
/
/
/
/
s*
, —
s~*
/
*>
\
>
K
X,
V
V
X
w
\
>s.
^\
\
1 —
1
CO
Hardnes
•
) 12:30 12:40 12:50 1:00 1:10 PM 1:30 '2:05
110 minutes rinse
60 gpm flow rate
6,600 gallons total flow
Rinse
Kgr Hardness. 20, 000
Salt used 600 Ib.
Salt per cu.ft. 5.5
Rinse Rate
62 gal/cu.ft.
0.56 gpm/ cu.ft.
2. 14 gpm/sq.ft.
200
100
73
-------
RADIUM-226 MATERIAL BALANCE
Figure 23 is a schematic drawing showing water treatment units and the
radium-226 radioactivity and concentrations at various stages in the
treatment process. Detailed radium computations are as shown in
Appendix B.
Applying the average 49 pCi/1 radium-226 value to the well pumpage
of approximately 1.34 million gallons gives a total radioactivity of
249 uCi passing through the iron removal filter during the 14 day
filter run. Dividing by a total of 15 zeolite softening and regen-
eration cycles of approximately 90,000 gallons each reduced the total
radioactivity furnished by the well for each regeneration to 16.6 uCi.
Likewise the composite total radioactivity of 25.2 uCi removal by the
iron filter backwash is reduced by the factor of 15 cycles to 1.60 uCi
for each softener cycle. This value subtracted from the well water
radioactivity approximates the radioactivity of 14.5 uCi in the iron
removal filter effluent.
Radioactivity removals in the zeolite softener backwash and brine rinse
were 0.23 uCi and 14.1 uCi respectively. Subtracting these two removal
values from the radium-226 radioactivity in the iron removal filter ef-
fluent leaves a difference of 0.66 uCi as compared with the 0.58 uCi
in the softener effluent. This is a reasonably good material balance
despite difficulties in securing accurate flow data in some stages of
the treatment process extending over the two week period. An excellent
reduction from an average of 49 pCi/1 in the well water to an average
of 1.9 pCi/1 in the softener effluent indicates an average radium-226
reduction of 96%.
74
-------
Figure 23
Ra-226 Distribution in Treatment Process
El don, Iowa
iron Removal and Zeolite Softening
Treatment Treatment
Unit Unit
Removals Effluents
uCi uCi
If f r\7 f ,,ri 1
f 1
49 pCi/1
- 1 An
14.5 uCi J
43 pCi/1
-0.23
14.77
-14.1
Well pumped 1.34 MG during
14 day period 249 uCi
15 regenerations @ 16.6 uCi
1^/1 Mf*
O*t Mb
Iron Removal Filter (4 Units)
Samples after 1 & 12 hrs
Filter , 6Q uc! f Miters
Rflrkwflsh i
(14 days) 250-770 pCi/1
Zeolite Softeners (2 Units)
(15 regenerations in 14 days)
Zeol i te 1 ^
p^r-|<-Wa<;h u./j MUi |
9-30 pCi/1
7pr»lifp 1 ^
Brine Rinse '**• ' ^c' 1
400-3150 pCi/1
by difference
Legend
Total
16.6 pCi|
4g pC5/l Concentration
i
Distribution
System
75
-------
SECTION 12.3
ESTHERVILLE
BACKGROUND DATA
Estherville is the county seat of Emmet County in northwest Iowa.
Estherville with, a population of 8108 persons,is the largest city
in Emmet County and is part of the Iowa Great Lakes recreational
area. Emmet county is primarily agriculturally oriented and has
shown a drop in population due to off-farm migration.
Estherville's industries include beef, pork, and poultry proces-
sing plants; feed milling, packaged foods, egg processing, chemi-
cal fertilizer and concrete products.
EXISTING WATER FACILITIES
Estherville presently gets its public water supply from six Jordan
aquifer wells ranging in depth from 750 to 780 feet. The wells
are described in Table 15.
Table 15
WATER SUPPLY WELLS - ESTHERVILLE
Approx.
Well Year Capacity Pumping
No. Drilled Depth (gpm) Rate (gpm) Aquifer
4 1941 780 750 400 Jordan
6 1954 775 1,000 850 Jordan
7 1956 775 1,200 500 Jordan
8 1958 756 1,200 900 Jordan
9 1965 750 1,200 700 Jordan
10 1972 772 1,200 800 Jordan
Estherville has two separate water systems, an industrial untreated
water system and a treated water system. All wells can be connected
to the raw water system with a separate elevated storage tank but only
one well, No. 8, was being used during the survey period to serve as
the raw water supply for the municipal treated water system. The raw
water system has only six customers which includes large industrial
users, such as the beef, pork, and poultry processing plants.
Figure 24 is a flow diagram of the Estherville ion exchange softening
plant. Raw water from Well No. 8 is pumped through a forced draft
aerator directly through gravity anthracite iron removal filters into a
140,000 gallon surface reservoir. High service pumps discharge
through four pressure vertical ion exchange softeners (figure 25)
at a normal rate of 800 gpm to the distribution system.
76
-------
Figure 24
Flow Diagram
Estherville, Iowa - Population 8,108 (1970)
Gravity Iron Removal Filter and Zeolite Softener Plant
October 8,
Well No 8
Depth 756'
Capacity 900 gpm
Parameter and
Percent Removal
Ra-226 Hardness Iron
pCi/1 mg/1 mg/1
-Well
5.7
915
2.0
Forced draft aerator
Anthracite gravity filters
2 cell 10'x 9' each
Total area 180 sqft Unit 90 sqft
Service rate 800 gpm @ k.5 gpm/sqft
Backwash rate 30 gpm/sqft
Volume 27,000
•Filter Effluent
5.1
in
915
Detention tank - 1^0,000 gal
Detention 140 min @ 1000 gpm
Pumps 1000, 850, 400, kOO, gpm
Zeolite softeners
k cell 9' diam 11' height
Total area 256 sqft Unit 6k sqft
Media volume 370 cuft 70" depth
Capacity 130,000 gal - 200 gpm
Service rate 200 gpm @ 3.12 gpm/sqft
Backwash rate 315 gpm § 4-9 gpm/sqft
Volume 6300 gal § 20 min
0.3
0.67
66%
Liquid caustic
Chlorine
Overall removal
35%
Distribution
System
95
95*
7.6
0.05
95
982
0.10
77
-------
Ion Exchange Softeners
Figure 25
Unsoftened water is added to the softened ion exchange softener
effluent to provide sufficient calcium carbonate for deposition of a
protective coating on the water mains. Liquid caustic and liquid
chlorine are also added to the plant effluent.
Iron filter backwash, softener backwash and spent brine rinse are
discharged to a storm sewer with final discharge to the Des Moines
River.
IRON FILTER AND ION EXCHANGE PERFORMANCE
Table 16 is a tabulation of the radiological and chemical analyses
performed on samples collected from No. 8 deep well furnishing the
raw water supply during the survey period and from various stages
in the iron removal, softening and regeneration cycles. Additional
mineral analyses are shown in Appendix A. Percentage removals of
radium-226, iron and hardness are also shown on the plant flow
diagram, Figure 24.
78
-------
Table 16
Radiological and Chemical Analysis
Esthervllle, Iowa Water Supply
October 8, 9, & 10, 1974
Sampl i ng Point
Well #8 756' 30 mln
Well #8 756' 6 hr
Iron Filter Eff 8 hr
Iron Filter Eff 27 hr
Iron Filter Eff 30 day
'Mron Filter Eff 7 day
*lron Filter Eff 15 day
Iron Filter BW 5 min
Iron Filter BW Comp
* Iron Filter BW 1-30' Comp
Softener Inf
Softener Inf
Softener #3 Eff 1 hr
Softener #3 Eff 50*
Softener #3 Eff 132,000 100%
Softener #3 Eff 142,000
Softener #4 Eff 25%
Softener #2 Eff 56,000
Combined Eff 6 hr
Combined Eff 10 hr
Blended Eff 4 hr
Softener #3 BW 5 min
Softener #3 BW Comp
Softener #3 Rinse 5 min
Softener #3 Rinse 10 min
Softener #3 Rinse 15 min
Softener #3 Rinse 20 min
Gross
Alpha
pCi/1
10
5.5
5.9
6.3
16
8.6
13
4154
227
144
9
13
2. if
3.3
2.3
3-9
2.3
4.0
5.9
1.4
7.0
223
226
160
470
128
10
Ra Hard-
226 ness
pCi/1 mg/1
6.2
5.2
4.9
5.3
8.1
3.0
4.2
1980
165
66
4.8
4.9
0.6
0.1
0.4
0.8
0.3
0.2
0.7
0.5
0.4
106
94
80
320
52
5.4
915
915
925
915
915
883
908
1450
1100
960
915
56
36
185
340
38
40
46
48
76
680
715
70000
63500
10800
1620
Total Alkalinity
1 ron
Solids P T pH Total Sol Ca
mg/1 mg/1 mg/1 mq/1 mq/l mq/l
1360
1350
1359
1344
1360
1325
1358
1399
1375
1361
1356
1385
1360
1315
1334
1357
1359
1360
1370
1395
1354
1367
97962
193000
48900
9195
7.1
0 367 7.1
7.5
0 372 7.7
0 358 7.8
0 394 7\7
7.25
7.4
7.3
7.4
7.55
0 386 7-5
7.35
7-25
7.5
7.45
7.45
0 396 7.6
3.2
7.3
7.3
6.2
5.9
0 546 6.9
7.25
2.0
1.6
0.71
0.64
2.8
0.05
0.17
1300
320
120
0.27
0.77
0.21
0.08
0.04
0.02
0.17
0.03
0.09
0.10
0.10
25
17
1 .0
0.98
0.34
0.26
240
1.6 240
240
240
2.8 240
220
0.7 230
420
290
240
240
17
11
28
120
10
18
13
13
20
150
170
15000
19000
3100
440
Mg
mg/1
84
83
84
84
83
82
82
93
86
84
83
6
4.1
30
140
4.0
5.0
3.9
3.8
6.9
73
75
8500
4200
820
160
Na
mg/1
64
59
57
58
55
64
58
57
57
430
420
370
110
44o
'»50
440
420
420
200
150
1200
24000
13000
3000
Mn Cl SO.
mg/1 mg/1 mq/T
2.5
0.24 3.0
8
5.5
0.27 2
3
3
1.5
3
19
0.01 3
2
4
5
11.
11
0.01 9-5
6
6
3
38000
86300
0.78 26000
5000
670
670
630
630
1400
^Samples collected January 30 - February 20, 1975
-------
Well
The 750 ft. deep No. 8 well pumped at a 900 gpm rate is the shal-
lowest Jordan sandstone well sampled during the project study.
The well samples collected at 30 minute and 6 hour intervals
showed a slight decrease in radium activity from 6.2 to 5.2 pCi/1
after the longest pumping period. The hardness, total solids and
other chemical parameters showed little or no significant change
during the pumping period. Hardness in the well water averaged
915 mg/1, total solids 1355 mg/1 and iron 1.8 mg/1.
Table 17 lists the concentrations and percentage removals of these
pertinent radium and chemical constituents through the iron removal
filter and softener units.
Table 17
Radium-226, Hardness and Iron Removals
Iron Removal-Zeolite Softener
Estherville, Iowa
October 8, 1974
Sampling Point
Ra-226
Percent
pCi/1 Removal
Hardness Iron
Percent Percent
mg/1 Removal mg/1 Removal
Well Supply 5.7
Iron Filter Effluent 5.1
Softener Effluent 0.3
Overall Removal 0.3
Blended Effluent 0.4
94
95
915
915
46
46
76
95
95
2.0
0.38
0.05
0.05
0.10
81
87
97
January 30-February 20, 1975 Composites
Iron Filter Effluent
7th day
15th day
Iron Removal Filter
3.0
4.2
47
26
0.05
0.17
97
91
The iron removal filter showed considerable variation in removals of
radium-226 and iron during two filter runs sampled during the first
survey in October, 1974 and the recheck survey during February, 1975.
The radium-226 was reduced from 6.2 and 5.5 pCi/1 values to 4.9 and
5.3 pCi/1 levels in the iron filter effluent at 8 hours and 27 hours
through the filter run during the October, 1974 survey. The
radium-226 content of the iron removal filter effluent at the end
of the 30 day filter run was 8.1 pCi/1 or an actual increase in the
effluent as compared with the influent levels. Likewise the iron
80
-------
content of the iron removal filter effluent on the 30th day of the
filter run increased to 2.8 mg/1 indicating possible sloughing of
iron from the filter.
The filter run of the iron removal filter had been increased about
a week to permit the survey sampling and filter backwash at a time
which would permit a visit by personnel of the U.S. Environmental
Protection Agency. Subsequent sampling of the iron removal filter
effluent with a shorter filter run indicated better radium and iron
removal as shown by Table 17.
The samples collected during the February, 1975 survey showed
radium-226 values of 3.0 and 4.2 pCi/1 in the 7th day and 15th day
composite samples of the iron removal filter effluent. Disregard-
ing the 30 day filter effluent value, the radium-226 removal
through the iron removal filter using average well supply values
and filter effluent values was 14% on the October survey and 47%
and 26% on the two composites in February.
During the February, 1975 survey, iron removal filter samples were
collected at two day intervals for iron analysis during the 21 day
filter run prior to backwash. These values are shown graphically
in figure 26. The graph shows iron content in the filter effluent
to be generally in the 0.05 to 0.3 mg/1 range as contrasted with
the 0.71 to 0.64 mg/1 values found in the earlier survey in October,
1974. These higher values were found following the longer 30 day
filter run indicating lower iron removal efficiency.
These results indicate some amount of radium-226 activity is removed
in a concurrent manner with the ferric oxides and hydroxides or
possibly ferrous carbonates. Relatively poor radium removal is
associated with the poor iron removal on the iron filter that had
been previously overloaded whereas better radium removal occurred
with the much improved iron removal during the February survey.
There was no visible color or turbidity in the iron removal filter
effluent or the softener influent samples reported in table 16. The
softener influent analyses showed iron determinations of 0.27 and
0.77 mg/1 which are similar to the filter effluent samples.
Likewise the backwash water from the softener showed no visible
color or turbidity indicating little suspended matter even though
an iron content of 17 mg/1 of iron was present.
The removal of total iron through the iron filter using the average
values of the well supply and the iron removal filter effluent
during the two sampling periods was 81 percent. The percentage of
iron removal and radium removal improved to 97% and 91% when the
filter effluent composite values of the February, 1975 survey were
used.
81
-------
FIGURE 26
TOTAL_IRON ANALYSIS
IRON REMOVAL FILTER RUN
16,854,000 GALLONS
JANUARY 30 TO FEBRUARY 20, 1975
0.7
11 13 15 17 19 20 21
0.0 -*
30 31 1
.TAN.
DAY g 1 2 4 6 8
IRON COMPOSITE 0.05
10 12 14 16 18 20 21.22
0.07
Ion Exchanger
Radiological and chemical analyses shown in Table 16 were collected at the
1 hour, 50%, 100% (132,000 gal.) and 110% (142,000 gal.) intervals through
the softening cycle of the #3 softener. Additional samples were also
collected from softeners #2 and 4, from the combined effluent and from the
blended effluent containing about six percent unsoftened water.
Radium-226
The radium-226 concentration was reduced from the 5.7 to 5.3 pCi/1 range to
a 0.1 range of values following ion exchange softening. The low value of
0.1 pCi/1 was recorded at 50% through the softening run with an average
radium-226 removal of 94% through the ion exchange unit and 95% overall as
82
-------
shown in Table 17.
Hardness
Total hardness was reduced from 915 mg/1 to an average hardness of 46 mg/1
through the ion exchange softener for an average hardness reduction of 95%.
Hardness values during the softening cycle on six samples from the various
filters ranged from 38 to 56 mg/1. These hardness values are somewhat higher
than expected and may indicate some loss of softening capacity over the
20 years of service of the softener.
The data indicates a slight decrease in hardness leakage after regeneration
with a rapid rise in hardness to 185 mg/1 compared to a radium-226 value of
0.4 pCi/1 at the end of the normal softening cycle as the exchanger media
was approaching exhaustion. The #3 softener was deliberately run 10,000
gallons past its normal regeneration time to determine the radium removal as
the exchanger media was nearing complete exhaustion. At this point the
hardness had risen to 840 mg/1 (raw water hardness 915/mg/l) as compared with
a radium-226 content of 0.8 pCi/1 (raw water average 5.7 pCi/1). The data
confirms other studies indicating radium removal continuing after hardness
removal capacity was exhausted.
Calcium and magnesium ions were reduced by the cation cation ion exchanger
from average raw water values of 240 and 84 mg/1 to 11 and 4 mg/1 respectively
at the 50% softening cycle point. There was a significant increase in
sodium content from an average of 60 mg/1 in the well water to 430 mg/1 in the
softened water due to exchange of the sodium for the calcium and magnesium
ions.
Approximately 6 percent unsoftened water was bypassed around the softener and
blended with the finished water being pumped to the distribution system. This
blended effluent had a radium-226 concentration of 0.4 pCi/1, a hardness
content of 76 mg/1 and an iron content of 0.1 mg/1 as shown in Table 16.
ION EXCHANGE REGENERATION
Samples for radiological and chemical analyses were collected from softener
discharges at various stages of the backwash, brine and rinse cycles during
regeneration. These values are also shown in Table 16. Table 18 shows the
regeneration and water usage data for the complete cycle.
These rates and quantities are shown in the plant flow diagram, Figure 24 and
Figure 27 showing the brine and rinse cycle.
83
-------
Table 18
Regeneration and Water Use Data
Softening
Backwash
Brine
Rinse
Time
10.8 hrs.
10 min.
22 min.
37 min.
Pumping
Rate
200 gpm
315 gpm
74 gpm
247 gpm
Total
Water
Quantity
130,000 gal
3,150 gal
1,630 gal
9,140 gal
144,000 gal
Backwash
The ion exchanger backwash was sampled by a grab sample at 5 min-
utes and by a composite of 5 samples collected over the 10 minute
backwash period. The radium-226 concentration in the backwash
composite increased to 94 pCi/1 and the iron content increased to
17 gpm although no suspended solids were visible in the effluent.
These analyses may indicate some radium is removed by filtration or
adsorption even though suspended solids were not apparent by visual
means.
Brine and Rinse Cycles
Saturated brine is pumped at a rate of 42 gpm from the salt storage
tank, diluted by 32 gpm of water from an injector for a total of 74
gpm for the 22 minute brine cycle. Salometer degree readings were
taken continuously to determine when the salometer readings in-
creased indicating chlorides of calcium and magnesium and the
excess regenerant salt were passing to waste from the softener.
Salometer degree readings were then taken at 5 minute intervals
along with samples for radiological and chemical analyses at these
intervals.
Figure 27 is a graph of the salometer degree readings (includes
other ions), hardness and radium-226 determinations of the four
samples collected during the brine cycle. Sampling extended into
the rinse cycle discharge period. Radium concentration increased
to a maximum of 320 pCi/1, hardness to 70,000 mg/1 and the salo-
meter degree reading 37 percent during the rinse cycle. Likewise,
total solids increased to a maximum of 193,000 mg/1, calcium to
19,000 mg/1, magnesium to 42,000 mg/1, sodium to 24,000 mg/1 and
chlorides to 86,300 mg/1.
84
-------
FIGURE 27
Estherville, Iowa
October 18, 1974
No. 1 Zeolite Softener Brine & Rinse Cycle
vO
CMrH
CM-^.
1 -rl
R)U
& P-
8
0
to rt
cncj
cu
C 01
•o rt
w
CflrH
w—
to
e
Salometer
Degrees
PM 4:50
10 mfn
15 gpm
50 gal
ckwash
Rate
/sqft
300 -
200 •
100
7,000 -
50,000 .
on nnn .
t-\it UUU
1 n nnn -
35 .
30 .
25 .
20.
15
i n -
1 U
c .
5
S
*
A
/\
/ ^
N
\ \
I »
/
/
/
s,
\
f—***
n
f \
\
^
/
5:00 5:10 5:
22 min
74 gpm
1,630 gal
Brine
v
\
"X^
20 5:30 5:^0 5:50
37 minutes
247 gpm
9,140 gal Ions
Rinse
. ^00
-70D
100
kgr Hardness 7,^00 — i Rinse Rate
Salt used 2,0^0 Ib 23 gal/cu.ft.
Salt per kgr 0.276 Ib 0.6? gpm/cu.ft.
Salt per cu.ft. 5-5 Ib 3.86 gpm/sq.ft
-------
A graph of salometer degree readings at 5 minute intervals from the
Nos. 1 and 4 softeners indicated similar salometer curves. The
maximum salometer readings were 53 and 40 compared with a reading
of 37 for the #3 softener on which samples were collected.
RADIUM-226 MATERIAL BALANCE
Figure 28 is a schematic drawing showing the water treatment units
and the radium-226 concentrations and total radioactivity at vari-
ous stages in the treatment process. The detailed computations are
shown in Appendix B.
Applying the average 5.7 pCi/1 radium-226 concentration value to the
well pumpage of 26.2 million gallons over the 30 day iron filter
run gives a total radium-226 radioactivity of 565 uCi in the well
water pumped. Using a 144,000 gallon total water usage in a com-
plete softening regeneration cycle gives 182 cycles during this
period or 3.10 uCi in the well water during a softener cycle.
The composite radium content in the iron removal filter backwash
was 54 uCi which reduced to a concentration of 0.30 pCi/1 for each
softener cycle. This value subtracted from the well water radio-
activity should have equalled the activity in the iron removal
filter effluent. Radioactivity removals in the ion exchange back-
wash and ion exchange brine rinse were 1.12 uCi and 2.13 uCi
respectively. It should be noted that the total radioactivity
level reductions by the iron removal filter backwash and ion ex-
change backwash and brine rinse are greater than the reduction in
radioactivity as shown in the zeolite softener effluent. Thus there
was a poor material balance of radium-226 through the treatment
units. The unusually long iron removal filter run of 30 days and
difficulty in securing a representative composite sample of this
filter effluent may have contributed to difficulty in securing a
good material balance. However an excellent reduction from an
average of 5.7 pCi/1 in the raw well water to an average of 0.3
pCi/1 in the softener effluent was attained as an average radium-
226 reduction of 95%.
86
-------
Figure 28
Ra-226 Distribution in Treatment Process
Estherville, Iowa
Iron Removal and Zeolite Softener Plant
Unit
Removals
jjCi
3.10
-0.30
2.80
-1.12
~775S~
-2J3
-0.45
Legend
Unit
Efficiencies
uCi
0.3 pCi/1
II Total
3.45 uCi I Radioactivity
5.7 pCi/1 Concentration
Aerator
Fi 1ter
Wei 1-30 day pumping 26.2 MG
144,000 Gal/regeneration
Iron removal filter
(2 units)
Sample after 8 & 27 hrs
Backwash
per
egenefttion
cycle
Composite 165 pCi/1
4 Zeolite filters
Zeoli te
Backwash
1.12
Composite 94 pCi/1
Zeolite
Rinse
2.13 uCJ
5.^ to 320 pCi/1
Composite 114 pCi/1
Distribution
System
87
-------
SECTION 12.4
GRINNELL
BACKGROUND INFORMATION
Grinnell is the county seat of Poweshiek County in Central Iowa,50
miles east of Des Moines. Grinnell,with a population of 8,402 is
the largest city in the county. The county is agriculturally
oriented and the city has a considerable amount of light industry
and agri-associated industry.
EXISTING WATER FACILITIES
Grinnell presently derives its water supply from four Jordan aqui-
fer wells described in the following table.
WELL WATER SUPPLY - GRINNELL, IOWA
Well No.
5
6
7
8*
Year
Drilled
1920
1926
1955
1974
2,250 feet
2,550 feet
2,500 feet
Aproximate
Pumping Rate
500 gpm
460 gpm
690 gpm
Aquifer
Jordan
Jordan
Jordan
Jordan
*Well No. 8 was not in operation at the time of the plant study.
Figure 29 is a flow diagram of the Grinnell ion exchange softening
plant. Raw well water is pumped through an aerator into a 1,000,000
gallon concrete surface reservoir. High service pumps discharge
through three vertical zeolite softeners (figure 30) at a normal unit rate of
330 gpm to the distribution system. Additional design information
regarding the iron removal filter and ion exchange softener is
given in the flow diagram.
Approximately 25 percent unsoftened water is added to the softened
water to provide sufficient calcium carbonate deposition for water
main protection. Liquid chlorine, phosphate and caustic soda ash
are also added to the plant effluent.
Iron filter backwash and softener backwash and spent brine rinse
are discharged to a storm sewer.
88
-------
Figure 29
Flow Diagram
Grinnell, Iowa - Populatro0\8,i»02 (1970)
Aeration and Zeolite Softener Plant
Well Nos 567
Depth ft 2250 2550 2500
Capacity gpm 500 460 690
Parameter and
Removal Efficiency
Ra-226 Hardness Iron
-Well Average
6.7
385
0.71
Tray aerator
Surface reservoir 1.0 mg capacity
Detention 2k hrs average
pumps 800, 800, 2000, gpm
Zeolite filters - Vertical
3 cells 8' diam 9' height
Total area 150 sqft V media
Media Volume 200 cuft
Capacity 200,000 gal 330 gpm
Service rate 330 gpm @ 6.6 gpm/sqft
Backwash rate 6.3 gpm/sqft
Volume 6000 gal/19 min
5.7
15*
387
42%
C12
Phosphate
Caustic Soda
Softener Effluent
Overall Removal
0.2
972
97%
11
97*
97%
0.03
93%
96%
•System
120
0.03
Distribution
Sys tern
89
-------
Table 19
Radiological and Chemical Analysis
Grinnell, Iowa Water Supply
July 8,
Sampl ing Point
Wei #5 2250' 10 min
V/el #5 2250' 30 min
Wei #5 2250' 4 hr
Wei #6 2550' 10 min
Wei #6 2550' 30 min
Well #6 2550' 4 hr
Well #7 2500' 3 hr
Softener #2 Inf 1 hr
Softener #2 Inf Dup
Softener #2 Inf '4 hr
Softener //2 Eff 10 min
Softener #2 Eff 252
Softener #2 Eff 50%
Softener #2 Eff 100%
Softener #2 Eff 110%
Softener #3 Eff 1 hr
Softener #1 Eff 12 hr
Softener #1 Eff Dup
Blended Eff 1 hr
Distribution System
Softener #2 BW 6 min
Softener #2 BW 10 min
^oftener #2 BW 15 min
''Softener #2 Rinse 10 min
-Softener #2 Rinse 20 m?n
-Softener #2 Rinse 30 min
-Softener #2 Rinse 35 mtn
"Softener #2 Rinse 40 min
Gross Ra
Alpha 226
pCi/1 PCi/l
10
12
14
12
16
23
5.*»
9.1
12
1.1
0.3
1.7
0.3
5.3
Nil
3.1
2.5
1.5
34
30
12
330
520
470
620
WO
7.1
6.1
6.2
7.3
7.6
7.2
4.1
5.8
5.6
0.3
0.1
0.2
0.9
1.7
0.2
0.7
1.4
1.4
18.7
12.5
6.0
210
320
290
260
220
Hard- Total
ness Sol ids
mg/1 mg/1
368 76*4
366 761
363 784
655 1791
MO 888
420 922
368 742
388 846
388 814
384 822
12 885
16 830
6 860
106 824
282 794
10 835
40 823
48 822
100 880
120 852
375 939
374 851
224 825
21400 17800
24000 59700
19800 56400
19500 70000
12640 60000
Al kal ini ty I ron
P
mg/1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
17
18
0
0
0
0
T
mg/1
306
298
298
264
316
334
263
294
294
290
315
294
292
292
293
295
298
294
328
330
290
296
294
264
pH Total
mg/1
7.35
7-3
7.35 1.1
7.25
7.05
7.3 0.26
7.3 0.76
7.65
7.55
7.55 0.41
8.2
7.45
7.7 0.03
7.3
7.3
7-7
7.4
7.4
8.65 0.14
8.6
7.15
7.25
7.3
6.6 0.13
6.65 0.20
7.0 0.25
6.8 0.23
7.0 0.23
Sol Ca
mg/1 mg/1
83
82
1.1 32
180
98
0.26 98
0.76 82
90
89
0.41 88
3.3
1.3
0.03 2.4
18
48
2.4
10
10
0.14 21
26
93
80
69
3900
5300
5120
4800
3500
Mg
mg/1
42
42
43
58
45
46
44
42
42
44
1.4
0.3
0.5
16
42
0.9
5
5.2
11
15
44
39
34
2800
2800
1700
1800
940
Na Mn Cl
mg/1 mq/1 mq/1
110
130
95
120
290
260
1980
8200
11000
13000
15400
0.01 18
0.01 24
0.01 16
0.01 22
0.01 21
0.01
21
16000
27500
32000
27000
13500
SOi,
mg/1
280
290
320
910
370
380
290
310
320
340
310
310
330
310
310
310
310
300
330
310
320
320
320
900
•''October 24, 1974
-------
ION EXCHANGE PERFORMANCE
Table 19 is a tabulation of the radiological and chemical analyses
performed on samples collected from the raw water supply and from the
various stages of aeration, sedimentation, softening and regeneration
cycles. Additional mineral analyses are shown in Appendix A. Percentage
removals of radium-226, iron and hardness "are also shown on the plant
flow diagram, figure 29.
Well
The three Jordan formation wells drilled to depths of 2250 to 2550 feet
and pumped at 460 to 960 gpm rates were sampled at various pumping times
to indicate possible changes during the survey period. Variations
occurred in the radium-226 concentrations during the 10 minute, 30
minute, and 4 hour sampling times on samples collected from wells 5 and
6. The four hour pumping period samples on these wells showed radium
concentrations of 6.2 and 7.2 pCi/1 compared with a 4.1 pCi/1 concen-
trations on well #7 at 3.2 hour pumping period. A radium-226 value on
a new well reported in April, 1975 showed a somewhat higher 8.1 pCi/1
radium concentration. The hardness, total solids and other chemical
parameters showed some variation between wells and pumping times.
Considering all factors the following average well water values were
used: radium-226 concentrations 6.7 pCi/1, hardness 385 mg/1, total
solids 817 mg/1 and iron 0.71 mg/1.
Aeration Sedimentation
Wells are pumped to a tray aerator located on top of a million gallon
capacity,covered concrete surface reservoir. The theoretical detention
time of 24 hours reduced the average iron content of 0.71 mg/1 in the
three well waters (assuming equal flows) to 0.41 mg/1 in the influent
pumped to the softeners for an iron removal of 42%. The variations in
the radiological and mineral characteristics of the wells, differences in
well pumping rates, reservoir levels and other factors make it difficul
to arrive at a firm expected removal of iron and radium. However the
reduction indicates that some amount of radium activity is removed by
adsorption and sedimentation with ferric oxides and hydroxides as well
as ferrous carbonate.
Ion Exchange
Radiological and chemical analyses shown in table 19 were collected at
ten minutes (3300 gal), 25%, 50%, 100%, (200,000 gal), and 100%
intervals through the softening or service cycle of the No. 2
91
-------
softener. Additional samples were collected from softeners No. 1
and No. 3 to verify results. A sample was also collected of the
blended effluent from the plant containing about 25 percent un-
softened water.
Radium-226
The radium-226 concentration was reduced from an average 5.7 pCi/1
in the softener influent to an average 0.2 pCi/1 range following
ion exchange softening for a radium removal of 96% due to ion
exchange. The data in table 19 indicates a radium increase from a
low of 0.1 pCi/1 at the 25% point in the softener run to 0.9 at the
100% point (200,000 gallons) when the softener is considered at the
point of exhaustion (106 mg/1 hardness) and is normally regenerated.
The softener was deliberately run to the 110% point (220,000 gal-
lons) past normal regeneration and the radium-226 value increased
to 1.7 pCi/1. Better radium removal (1.7 pCi/1) was being accom-
plished than hardness removal (282 mg/1) indicating radium removal
continuing after hardness removal capacity was exhausted.
Hardness
Total hardness was reduced from an average hardness of 387 mg/1 in
the softener influent to an average hardness of 11 mg/1 through the
ion exchange process for a hardness reduction of 97%. Hardness
values during the softening cycle on four samples from various
filters ranged from 6 to 16 mg/1.
The data in table 19 indicates rapid rise to 106 mg/1 (raw water
hardness 387 mg/1) of hardness at the end of the normal softening
cycle which compares to the radium-226 concentration rise to 0.9
pCi/1. The hardness increased to 282 mg/1 at the 110% point past
the normal regeneration time.
Calcium and magnesium ions were reduced by the cation exchanger
from an average raw water value of 88 and 44 mg/1 to 3 and 1 mg/1
respectively in the normal softening range. During the exchange
cycle no significant changes occurred in concentration of total
solids, alkalinity or sulfates. There was a significant increase
in sodium from an average 110 mg/1 to 275 mg/1 in the softened
water due to exchange of the sodium for the calcium and magnesium
ions.
Approximately 25 percent unsoftened water was bypassed around the
softener and blended with the finished water being pumped to the
finished distribution system. This blended effluent had a radium-
226 concentration of 1.4 pCi/1, a hardness content of 100 mg/1 and
an iron content of 0.14 mg/1 as shown in table 19.
92
-------
Ion Exchange Softener
Figure 30
ION EXCHANGE REGENERATION
Samples for radiological and chemical analyses were collected from
softener discharges at various stages of the backwash, brine and
rinse cycles. These values are also shown in table 19. Table 20
lists the regeneration stages and water usage data.
Table 20
Regeneration and Water Use Data
Softening
Backwash
Brine
Rinse
Time
11 hours
22 minutes
32 minutes
60 minutes
Rate
150 gpm
320 gpm
90 gpm
117 gpm
Water
Quantity
200,000 gal.
7,000 gal,
2,900 gal,
7,000 gal,
These rates and quantities are also shown in the plant flow diagram,
figure 29.
Backwash
The ion exchanger backwash was sampled at the 6, 10 and 15 minute
intervals through the 22 minute backwash to determine changes in
the radiological and chemical analyses during the backwash (table
93
-------
19). The initial 6 minute radium-226 value was 18.7 pCi/1 with a
decrease to 10 pCi/1 at the 10 minute interval and to 6.0 pCi/1 at
the 15 minute interval which is the approximate raw water radium
concentration.
The ion exchanger backwash was highly rust or yellow colored but
with little visible suspended solids. Unfortunately no iron analy-
ses were performed on these samples. These radium analyses do
indicate that some radium is removed by filtration or absorption
of radium by the iron oxides, hydroxides or carbonates.
Rinse Cycle
Saturated brine is pumped by an ejector from a saturated brine
storage tank for the 32 minute brine cycle. Salometer degree
readings were taken continuously to determine when the salometer
reading (indicating specific gravity) increased, indicating chlo-
rides of calcium and magnesium and the excess regenerant salt were
passing from the softener. Salometer readings were then taken at 5
minute intervals and sampled for radiological and chemical analyses
at 10 minute intervals to indicate changes during the brine-rinse
cycle.
Figure 31 is a graph of the salometer degree readings (includes
other ions), hardness and radium-226 determinations of the five
samples collected during the brine cycle. Sampling was extended
into the rinse cycle discharge period. Radium-226 concentrations
in the brine rinse increased to a maximum of 320 pCi/1, hardness
increased to 19,800 mg/1 and the salometer reading rose to 17
percent. Total solids increased to a maximum of 59,700 mg/1,
calcium to 5,300 mg/1, magnesium to 2,800 mg/1, sodium to 15,400
mg/1 and chloride to 32,000 mg/1.
RADIUM-226 MATERIAL BALANCE
Figure 32 is a schematic drawing showing water treatment units and
the radium-226 radioactivity at various stages in the treatment
process. Detailed computations are shown in Appendix B.
Applying the average 6.7 pCi/1 concentration value to the well
pumpage of 213,000 gallons (including waste backwash and brine
rinse) for a complete softener service and regenerant cycle gives a
total radium radioactivity of 5.46 uCi in the well pumpage for the
complete cycle. Aeration settling in the 1,000,000 gallon (24 hour
detention) ground storage tank reduced the radium-226 concentration
to 5.7 pCi/1 for a total radioactivity of 4.66 uCi.
94
-------
FIGURE 31
Grinnell, Iowa
October 29, 1974
No. 2 Zeolite Softener Brine & Rinse Cycle
1 1-1
n) u
p^ CY,
o
o
co td
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e
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6 M
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rH 0)
rt Q
C/l
*"' 2:00 2ilOoo
400
200 -|
inn -
sn nnn-
10,000
30
in -
IU
' 2:3
f
/
/
+
_s
X
0 2:1
,S"
x^
**^~
^ *
»0 2:
•~^^,_
^'^^
N.^^
^^
50 3:1
*-»
^
30 3:
~ »
--^
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LO
V
\
V,
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\
X
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•
Ann -
•ann .
\
1UO
3:.
0
rf
Q
c
«T
^
ct
T
50
22^min N.
318 gpm g
7,000 gal -jj
«
Backwash
Rate 6.34 gpm/sqft
32 min contact
90 gpm
2,900 gal
Brine
60 min rinse
117 gpm flow rate
7,000 gal total flow
Rinse
Kgr Hardness 20,000
Salt used 1,454 Ib.
Salt per cu.ft.7.27 Ib
Rinse rat a
35 gal/cu.ft.
0.49 gpm/cu.ft.
2.3 gpm/ sq.ft.
95
-------
Remova1s
Thru
Unit
5-46
4.66
Figure 32
Ra-226 Distribution in Treatment Process
Gri nnel1, Iowa
Aeration, Detention and Zeolite Softener Plant
-0.27
-4.12
0.27
by difference
Legend
Unit
Effluents
uCi
I 5.46 uCi
6.7 pCi/1
I 4.66 uCi |-
5.7 pCi/I
I 0.16 uCi I
0.2 pCi/1
,- ,n ,-• I Total
5-^° UC| I Radioactivity
6.70 pCi/1 Concentration
Well 213,000 gallon/cycle
Aerator
Detention Tank
24 hour detention
3-Zeolite FiIters
Backwash
•J0.27 uCi
12 pCi/1 (Composite)
Brine Rinse
4.12 yCi|-
210-320 pCi/1
Di stribution
System
96
-------
The ion exchanger reduced the radium-226 concentration to 0.2 pCi/1
and a total activity of 0.16 uCi for a reduction of 96.5 percent in
the softener and an overall reduction of 97 percent. Backwash of
the zeolite filter contained 0.27 uCi of radium-226 total radio-
activity produced by a concentration of 12 pCi/1 and the brine
rinse contained 4.12 uCi of radium radioactivity produced by con-
centrations of 210-320 pCi/1 in five samples composited from the
rinse. Subtracting the activity removed from the system by the
zeolite backwash and brine rinse from the activity remaining in the
detention tank leaves a difference of 0.27 pCi compared with the
actual 0.16 uCi in the final effluent of the softener. This good
correlation indicates a good material balance through the treatment
system.
97
-------
SECTION 12.5
HOLSTEIN
BACKGROUND DATA
Holstein is located in Ida County in Northwest Iowa and located
about 12 miles north of Ida Grove,the county seat of Ida County.
Like much of Iowa, Ida County's economy is agriculturally oriented
and with farm consolidation, the population of Ida County has de-
creased from 1950 to 1970. However the Town of Holstein with a 1970
population of 1445 has been able to make moderate population in-
creases probably due to light industry in the community.
EXISTING WATER FACILITIES
Holstein presently derives its public water supply from a 644 ft.
deep well with a standby source from a 428 ft. deep well described
in table 21.
TABLE 21
WATER SUPPLY WELLS
Well No. Year Drilled Depth Capacity Aquifer
1 1937 644' 250 gpm Dakota
2 1952 428' 90 gpm Dakota
Figure 33 is a flow diagram of the Holstein iron removal and ion
exchange softening plant. Water from the well is pumped at a rate
of 250 gpm to a forced draft aerator located above a 27,000 gallon
concrete surface storage tank. Transfer pumps of 220 gpm capacity
pump the water from the ground storage tank through a 4-cell hori-
zontal pressure iron removal filter containing anthracite media (figure 34)
The iron filters are followed by two vertical ion exchange softeners
with a rated capacity of 103.5 gpm each. A small percentage of
unsoftened water is added to the softener effluent along with the
addition of chlorine and soda ash prior to entering a 200,000 gallon
surface storage reservoir. The unsoftened water is added to the ion
exchange softener effluent to provide for deposition of a protective
coating on the water mains. Two 800 gpm high service pumps then
transfer the treated water from the ground storage reservoir to the
distribution system.
Iron filter backwash and softener backwash and spent brine are dis-
charged to a sanitary sewer which discharges to the municipal lagoon
waste water treatment system. The iron filters must be washed
98
-------
Figure 33
Flow Diagram
Holstein, Iowa - Population \kk$ (1970)
Pressure Iron Removal Filter and Zeolite Softener Plant
Well No 1
Depth 6W
Capacity 250 gpm
Parameter and
Removal Efficiency
Ra-226 Hardness Iron
pCi/1 mg/1 mg/1
-Well
13
920
1.8
Forced draft aerator
1250 cfm
Surface detention
Capacity - 27,000 gal
Detention 110 min @ 250 gpm
------------------ Detention
10
870
Filter transfer pump 220 gpm
Anthracite pressure filter
1* Cell 8' diam - 16' long
Total area 118 sqft Unit 29-5 sqft
Service rate 220 gpm @ 1-72 gpm/sqft
Backwash rate 295 @ 10 gpm/sqft
1.6
m
•Iron Filter
7.2
28*
885
0.05
97*
Zeolite softeners
2 Cell 8' diam - 9' height
Total area 128 sqft Unit 32 sqft
Media Volume 137 cuft depth 58"
Capacity 55,000 gal
Service rate 110 gpm '@ 3-4 gpm/sqft
Backwash rate 1AO gpm @ l*.k gpm/sqft
Backwash Volume 1800 gal
-C12
-Soda ash
Softener
Overall Removal
0.5
93*
36%
18
972
981
•System 0.8
0.02
60%
33%
0.06
Distribution System
99
-------
Iron Removal Filter
Figure 3k
during low sewer flow periods during the very early morning hours to
prevent flooding of home basements in the vicinity of the water
plant.
IRON FILTER AND ION EXCHANGE PERFORMANCE
Table 22 is a tabulation of the radiological and chemical analyses
our stages in the aeration, iron removal, softening and regeneration
cycles. Additional mineral analyses are shown in Appendix A. Percentage
removals of radium-226, hardness and iron are shown in Figure 33.
Well
The 644 ft. deep well used as the raw water supply for Holstein is
the only well in the project study withdrawing water from the Dakota
Sandstone formation. The well samples collected at the 30 minute
and 4 hour intervals showed a slight increase in radium-226 radio-
activity from 12 to 14 pCi/1 for the longer pumping period. Other
chemical parameters showed no significant changes during the pumping
period. The hardness in the well water averaged 910 mg/1, total
solids 1355 mg/1 and iron 1.8 mg/1. The well water ranked as one of
the hardest waters sampled in the project study.
100
-------
Table 22
Radiological and Chemical Analysis
Hoi stein, Iowa Water Supply
October 24 & 29, 1974
Gross Ra Hard- Total Alkalinity
I ron
Sampl ing Point
Well #1 644' 30 min
Well #1 644' 4 hr
Aeration-Detention Eff
Iron Filter Eff 3 day
1 ron Fi 1 ter Eff 7 day
Softener A Eff 15,000 gal
Softener A Eff 25,000 gal
Softener A Eff 55,000 gal
Softener B Eff 25,000 gal
Softener B Eff 47,000 gal
Blended Plant Eff
Distribution System
Iron Fi Iter BW Comp
Softener A BW Comp
Softener A Rinse 5 min
Softener A Rinse 10 min
Softener A Rinse 15 min
Softener A Rinse 20 min
Softener A Rinse 25 min
Alpha
pCI/1
35
26
32
34
32
0.9
1.9
0.8
4.0
2.9
4.0
3.9
240
26
260
1700
2000
1700
110
226
pCi/1
12
14
10
7
7.3
0.7
0.4
0.3
0.5
1.9
1.0
0.8
80
7.8
210
700
1100
800
70
ness
mg/1
900
920
870
890
880
28
15
13
52
382
130
346
900
890
15400
78000
65500
33000
3900
Solids P T pH Total Sol Ca
mg/1 mg/1 mg/1 mg/1 mg/1 mg/1
1540
1510
1510
1510
1500
1500
1490
1470
1480
1460
1490
1490
1530
1510
72600
166000
211100
169000
29100
7.1
0 288 7.1
0 290 7.6
7.3
0 284 7.35
7.5
0 276 7.45
7-5
7.65
7-6
7.6
7-7
7.4
7.4
6.4
0 98 6.0
5.9
6.25
7.2
1.8
1.8
1.6
0.01
0.09
0.09
0.03
0.02
0.06
0.02
0.01
0.06
69
0.13
0.22
0.78
0.97
0.76
0.11
240
240
240
240
240
5.6
4.0
2.0
12
59
33
90
240
240
2800
20000
20000
10000
1200
Mg
mg/1
69
69
69
69
69
3.4
1.3
1.0
3-9
57
12
31
69
69-
2000
5000
3800
2000
260
Na Mn Cl
mg/1 mg/1 mg/1
110
110 0.
110 0.
120
110 0.
520
510<0.
520
530
350
520
420
1160
130
14600
19000
40000
82000
12600
8
15 7
14 7
8
01 8
14
01 10
8
8
6
30
16
2
9
37000
73000
97500
90000
17000
mg/T
800
790
790
790
1200
-------
Table 22 lists the concentrations and percentage removals of these
pertinent chemical constituents through the process. During the
survey period consistent salt dosages could not be applied to the
softeners due to operating difficulties with the brine pump and the
lack of an operable brine meter which prevented automatic operation
of the softening and regeneration cycles. Emergency main repair
work by the water plant operator also prevented regeneration at pro-
per intervals.
Iron Removal Filter
Aeration and a theoretical settling time of 110 minutes apparently
reduced the radium-226 concentration and iron content from 13 pCi/1
and 1.8 mg/1 in the well water to 10 pCi/1 and 1.6 mg/1 respectively
in the settled effluent. These values indicate radium and iron
removals of 23% and 11% respectively by aeration and settling only.
The radium-226 and iron concentrations of 10 pCi/1 and 1.8 mg/1 respec-
tively were reduced by passage through the iron removal filter to
7.2 pCi/1 and 0.05 mg/1 respectively. These values indicate radium
and iron removals of 28% and 97% respectively through the iron
removal filter.
Ion Exchange
Radiological and chemical analysis shown in table 22 were collected
at the 15,000, 25,000, and 55,000 gallon intervals through the
softening cycles of softener A. As described previously there were
difficulties in applying the proper salt dosage during regeneration
and excessive salt was applied to this softner. The softening cycle
exceeded 65,000 gallons without exhaustion rather than the design
55,000 gallon capacity. Additional samples were collected from
softener B to confirm efficiency of this unit and from the blended
plant effluent.
Radium-226
Table 22 shows the radium-226 concentrations were reduced fron an
average of 7.2 pCi/1 to an average of 0.5 pCi/1 following ion ex-
change softening for a removal of 93% through Softener A. Two
radium samples collected from softener B showed values of 0.5 pCi/1
at 25,000 gallons and 1.9 pCi/1 at 47,000 gallons indicating this
softener may not have been regenerated properly due to the brine
pump problems. Hardness removal was not as good and both the radium
and hardness concentrations were increasing before the normal regen-
eration time.
102
-------
Hardness
Total hardness was reduced from 890 mg/1 to an average hardness of 18 mg/1
through the ion exchange softener for an average hardness reduction of
98%. Hardness values on four samples collected during the softening
cycle ranged from 13 to 52 mg/1 indicating some hardness leakage with
this high hardness water.
It had been planned to run sofener A approximately 10% past its normal
point of exhaustion. However, the softener apparently had received
an excessive salt dosage at the previous regeneration and was producing
a soft water at 65,000 gallons.
Calcium and magnesium ions were reduced by the cation exchanger from
average raw water values of 240 and 69 mg/1 to average softened values
of 4 and 2 mg/1 respectively. No significant changes occurred in
concentration of total solids, alkalinity and sulfates during the sodium
ion exchange softening cycle.
There was a significant increase in sodium from 110 mg/1 in the raw
water to 520 mg/1 in the softened water due to exchange of the sodium
ion for the calcium and magnesium ions. This laboratory sodium value
of 250 mg/1 in softener A is approximately the same as a calculated
value of 534 obtained by adding a calculated sodium addition through
exchange to the laboratory raw water values.
ION EXCHANGE REGENERATION
Table 22 also indicates the radiological and chemical analyses for the
samples collected from the softener discharges at various stages during
regeneration. Table 23 gives the best available water usage data
during regeneration. Some flows are design rates or estimated rates
which could not be checked in the field. Likewise during the sampling
period, lack of automatic softener operation because of metering
equipment failure and the brine pump problem caused considerable softener
overrun at times with unsoftened water reaching the distribution system.
Table 23
Regeneration and Water Use Data
Water
Cycle Time Rate Quantity
Softening 10 hrs. 110 gpm 65,000 gal
Backwash 13 min. 140 gpm 1,800 gal
Brine 28 min. 28 gpm 780 gal
Rinse 45 min. 60 gpm 2,700 gal
TOTAL 70,280 gal
103
-------
These rates and quantities are shown in the plant flow diagram figure
33 and in figure 35 showing the brine and rinse cycle.
Backwash
The ion exchanger backwash sample was composited at two minute
intervals over the 13 minute backwash period to determine changes in
the radiological and chemical analyses during the backwash. A radium-
226 concentration of 7.8 pCi/1 indicated little radium was being
removed from the filter by the backwash process. Other parameters
were quite similar to the iron filter effluent used for the backwash.
No visible color or suspended solids were noted in the backwash
water indicating excellent removal of iron in the iron removal
filter.
Brine and Rinse Cycle
Saturated brine is pumped from a sump and diluted by an ejector flow
before passing through the exchange media. Due to brine pump repair
needs and lack of a brine meter, accurate rates of flow and amount
of brine to the exchanger could not be determined. Salometer degree
readings were taken to determine the time at which chlorides of
calcium and magnesium and excess regenerant were passing from the
softener. Salometer readings were then taken at five minute inter-
vals and samples for radiological and chemical analyses at five
minute intervals to indicate changes during the brine-rinse cycle.
Figure 35 is a graph of the salometer degree readings (includes other
ions), hardness and radium-226 determinations of the five samples col-
lected during the brine-rinse cycle. Radium-226 concentrations in the
rinse increased to a maximum of 1100 pCi/1, hardness to 78,000 mg/1
and the salometer degree readings to 50 percent. The steep salometer
degree graph may indicate the brine is being applied too fast with a too
short contact time as compared with a recommended "bell" curve. Total
solids in the rinse increased to a maximum of 211,100 mg/1, calcium to
20,000 mg/1, magnesium to 5,000 mg/1, sodium to 82,000 mg/1 and chlo-
rides to 97,500 mg/1.
RADIUM-226 MATERIAL BALANCE
Figure 36 is a schematic drawing showing the water treatment units
and the radium-226 radioactivity at various stages in the treatment unit.
The detailed computations are shown in Appendix B. Applying the average
13 pCi/1 radium-226 concentration value to the well pumpage of 1.09
million gallons over the 7 day iron filter run gives a total radium-226
radioactivity of 53.7 uCi in the well water pumped during the perod.
Using 14 softener regenerations (2/day) gives a total softener service
and regeneration cycle water usage of 76,000 gallons and a radium-226
104
-------
FIGURE 35
Holstein, Iowa
October 29, 1974
No. 1 Zeolite Softener Brine & Rinse Cycle
vO
£N
CM
k
Hardness
Salometer
BW 9:2
13 min
140 gpm
1,800 gal
Backwash
Rate
10 gpm/sq. ft
1 000 -
800 -
600
T-I Ann J
?1 SOO -
P.
?on -
i nn -
1UU
ff\ f*n nnn -
PI OUjUUU
o
cfl
CJ
to 4U,UUU
n)
6 on nnn
/U,UUU
i n nnn -
1U,UUU
50 -
40 -
CO
Q) 30 -
-------
Figure 36
Ra-226 Distribution in Treatment Process
Hoi stein, Iowa
Iron Removal and Zeolite Softener Plant
Remova1s
Thru
Unit
uCi
3-83
2.9*1
-2.30
0.57
by difference
Unit
Effluents
uCi
3-83
13 pCi/1
Well Week Pumping 1.092 MG
76,000 gal/Regeneration Cycle
Aerator
Detention Tank
2 hr detention
- 1 ron Removal Filters
0.02 uCi
80 pCi/1 (Composite)
2-Zeolite Softeners
7.8 pCi/1
irlnp. Rinse |2 30 ci
I—_
70-1100 pCi/1
12 pCi/1 Concentration
Distribution
System
106
-------
radioactivity of 3.83 yCi for each softener cycle. The 76,000 gallon
water usage during this entire softener cycle is greater than the
design 55,000 gallon softening cycle and other backwash, brine and rinse
waters indicating regenerations were not occurring at proper intervals.
Settling of the iron in the detention tank (2 hour detention) apparently
reduced the radium-226 concentration to 10 pCi/1 in the aerated and
settled water for a radioactivity of 2.94 pCi. The composite radium-226
activity in the filter backwash of only 0.89 yCi was allocated to
0.025 yCi for each of the 14 softener cycles. This value subtracted
from the detention tank radioactivity should have approximated the radio-
activity in the iron removal filter effluent. Radioactivity removals in
the ion exchange backwash and brine rinse were 0.05 yCi and 2.30 yCi
respectively.
Subtracting these two waste water radioactivity values from the 2.92 yCi
activity leaves a difference of 0.57 yCi which is reasonably close to
the 0.12 yCi radium-226 value found in the ion exchange softener effluent.
A 96% reduction in radium-226 was obtained between the raw water (12
pCi/1) and the softened effluent (0.5 pCi/1).
107
-------
SECTION 12.6
GENERAL ION EXCHANGE
TREATMENT MEDIA
Samples were collected of salt used for sodium cycle regeneration,
anthracite media from an iron removal filter and polystyrene resin
cation exchange media from the Estherville ion exchange softening plant.
Radiological analyses were performed on the treatment media to determine
radium-226 accumulations in the media.
The ion exchange resin media samples were collected after backwash by a
vertical core sample taken by pushing a IV plastic tube through the 70"
media depth just as the bed was being expanded by opening the backwash
valve. The bed then was drained completely and the plastic tube core
sample withdrawn from the bed. The plastic tube core sample was cut
into sections for radiological analysis of the radium content in the
bottom, middle and top areas of the softener bed.
Radiological samples on the three types of samples were performed by the
State Hygienic Laboratory. Difficulties were encountered in preparing
the polystyrene resin media for analysis. Duplicate core samples were
also submitted to the Radiochemistry and Nuclear Engineering Facility,
Office of Radiation Programs of the U.S. Environmental Protection Agency
at Cincinnati, Ohio, for gamma spectral analysis. The results of the
radiological analyses of the two laboratories are shown in Tables 24 and
25.
In addition to these analyses, William L. Brinck of the Radiochemistry and
Nuclear Engineering Branch and Dr. G. Jacobson, EPA Region VII, conducted
measurements of radiation exposure rates on the vertical ion exchange
tank surfaces with a portable 5 cm x 5 cm Nal (Tl) survey meter.
There was no significant variation in exposure rates on the surface of
the tanks during the course of the operating cycle. Thus, over a period
of years there is a substantial residual of radioactivity retained
within the media which is not removed during regeneration. From the ex-
posure rate measurements and ion exchange core samples, it was deter-
mined that the higher concentration of retained radioactivity is located
near the interface of the ion exchange media and supporting sand and
gravel in the lower portion of the tanks. (See Appendix F.)
SALT UTILIZATION BY ION EXCHANGE
Tables in Appendix E contain computations regarding the salt efficiencies
of the four ion exchangers. The salt efficiency, calculated by dividing
the salt utilized in removing the hardness by the salt dosage, varied from
55 to 44 percent. These efficiencies indicate about two times the theoreti-
cal salt dosage is necessary for media regeneration or conversely about
half of the salt dosage passes out of the exchanger or brine waste during
the regeneration cycle.
108
-------
TABLE 24
Salt and Media Sample Radiological Analysis
Estherville, Iowa
State Hygienic Laboratory
Des Moines, Iowa
Sample Gross Alpha Ra-226
pCl/g
Regeneration Salt (Prior to Use) 0.07
Leached Sediment on Anthracite 140*
Residue 460*
Softener Resin (top) Soluble Portion 37* 43*
Residue 280*
Softener Resin (middle) Soluble Portion 9.3** 9.6*
Residue 140*
Softener Resin (bottom) Soluble Portion 9.0** 9.7*
Residue 160*
*pCi/g of original raw granules.
**Gross dissolved soluble reading is slightly smaller than radium-226
results, because of heating process to eliminate corrosive compounds.
TABLE 25
Anthracite & Ion Exchange Core Sample Gamma Spectral Analysis
Estherville, Iowa
National Environmental Research Center
Cincinnati, Ohio
Sample Ra-226 Ra-228
Anthrafilt (pCi/gm) 225+6 72+2
Ion Exchange Core
Top (pCi/ml) 36.9 + 3.1 12.4 + 0.9
(pCi/gm-wet) 67.9 + 5.7 22.8 +1.6
(pCi/gm-dry) 79.4 + 6.7 26.7 + 1.9
Middle (pCi/ml) 37.1 + 3.2 12.1 + 0.9
(pCi/gm-wet) 62.2+ 5.4 20.3+1.4
(pCi/gm-dry) 72.2+ 6.3 23.6+1.7
Bottom (pCi/ml) 55.7+ 6.1 16.6+1.7
(pCi/gm-wet) 103.8+11.3 30.9+3.1
(pCi/gm-dry) 116.4+12.7 34.7+3.5
109
-------
IOWA EXCHANGE MEDIA
Table 26 is a description of the ion exchange media utilized by the
municipalities.
TABLE 26
Ion Exchange Media
Municipality Equipment Media (1) Manufacturer
Eldon General Filter Dowex HCR Dow Chemical Co.
Estherville Permutit Permutit-Q (2) Permutit Co.
Grinnell Refinite Amberlite & Rohm & Hass
Dowex Dow Chemical Co.
Holstein General Filter Dowex HCR Dow Chemical Co.
(1) All except Estherville are sulfonated polystryene cation exchanger
resins with a capacity of approximately 20 Kgr/cu.ft. at a salt
dosage of 5 Ibs. NaCl/cu.ft.
(2) Specifications state Permutit-Q has a zeolite exchange capacity of
7.4 Kgr/cu.ft. at a salt dosage of 5.5 Ibs. NaCl/cu.ft.
SODIUM INCREASE THROUGH ION EXCHANGE
Table 27 is a tabulation of well water hardness and sodium content and
the calculated and actual sodium increases in the softened and blended
water after the sodium ion exchange process. The basis of concern with
sodium in drinking water is the treatment of patients with congestive
heart failure, hypertension and certain other kidney and liver diseases.
Both the Estherville and Holstein water supplies had considerable in-
creases in sodium content due to high hardness even though initial
contents were low. The Holstein supply had the highest calculated and
actual sodium content. During the course of the survey, approximately
20 persons came to the Holstein plant daily to secure unsoftened water
in jugs or other containers. These individuals had been advised by
their medical doctors to use the unsoftened water for drinking and
cooking purposes. This was not a common practice at the other ion
exchange softening plants.
110
-------
Table 27
Sodium Increases Thru Ion Exchange Plants
Town
Eldon
Esthervi 1 le
Grinnel 1
Holstein
Well
Hardness
Raw
mg/1
375
915
387
920
Initial
Sod i urn
Raw
mg/1
270
6k
120
110
Sod i urn
Increase
due to
Hardness
mg/1
(0
173
422
178
424
Initial
plus
Hardness
Sodium
mg/1
(2)
443
486
298
534
Actual
Sod ium
After
Ion
Exchange
mg/1
(3)
430
420
290
520
System
Sodium
After
Blend
mg/1
420
420
260
420
Comparable
Changes in
Ra-226 pCi/1
Raw.
49
5-7
6.7
12
Fin.
1.9
0.3
0.2
0.5
Sys.
8
0
1
0
.6
.4
.4
.8
(1) Sodium increase = Total hardness * 2.17
(2) Initial Sodium plus calculated sodium due to hardness
(3) Laboratory analysis of zeolite softener effluent
-------
SECTION 13
LIME-SODA ASH SOFTENING
SECTION 13.1
PROCESS DESCRIPTION
The hardness of almost all water supplies is caused by the presence ir.
solution of calcium and magnesium compounds. Other bivalent ions such
as strontium, ferrous iron and manganese may contribute to the hard-
ness to a much lesser degree. The softening process consists of remov-
ing a part of these salts from the water to reduce the hardness to a
predetermined value consistent with reduction of detergent consumption,
the control of scale formation, and other factors which make for a high
quality water. Radium-226 is a divalent ion which would be expected to
be removed with the other divalent ions in the softening process.
Calcium and magnesium bicarbonates are alkaline minerals designated as
"carbonate hardness" and calcium and magnesium sulfates or chlorides and
nitrates are neutral salts designated as "non-carbonate hardness. The
alkalinity determination on raw water ordinarily measures the carbonate
hardness but in some softened waters alkalinity may also include some
sodium alkalinity if the total alkalinity exceeds the total hardness.
Sodium alkalinity is often termed "negative non-carbonate hardness"
since on reacting with lime, sodium carbonate is formed where it is used
for removing noncarbonate hardness. The noncarbonate hardness is mea-
sured by the difference between the total hardness and the carbonate
hardness and requires soda ash for its reduction or removal. The sum of
the alkalinity plus the noncarbonate hardness equals the total hardness
if the water contains no sodium alkalinity.
This process of softening depends on the use of lime and soda ash to
change the soluble calcium and magnesium compounds into nearly insoluble
compounds which are flocculated, settled, and filtered. The chemical
reactions are shown below with the precipitated compounds underlined.
C02 + Ca(OH)2 = CaC03 + H20 (1)
Ca(HC03)2 + Ca(OH)2 = 2CaC03 + 2H20 (2)
Mg(HC03)2 + Ca(OH)2 = CaCOg + MgC03+2H20 (3)
MgC03 + Ca(OH)2 = Mg(OH)2 + CaC03 (4)
MgS02 + Ca(OH)2 = Mg(OH)2 + CaS04 (5)
CaS04 + Na2C03 = CaC03 + Na2S04 (6)
The carbon dioxide is not hardness-forming but it must be removed by
lime; also the magnesium carbonate produced in reaction (3) is not
sufficiently insoluble for effective removal and so must be changed by
additional lime, as in reaction (4) to magnesium hydroxides: The cal-
112
-------
cium sulfate produced in reaction (5) is soluble and must be changed to
calcium carbonate by reaction (6) indicating the need for using soda
ash; while soluble calcium and magnesium chlorides are also removed by
soda ash with reactions similar to (6).
EXCESS LIME TREATMENT FOLLOWED BY RECARBONATION
The cities of Webster City and West Des Moines in the project study
employ the excess-lime treatment followed by recarbonation. With hard-
waters containing 40 mg/1 or over magnesium (as CaCO-j), treatment with
excess lime to remove magnesium is usually necessary. The process in
both cities consists of primary suspended solids contact only and sedi-
mentation with lime treatment to precipitate the magnesium. After the
precipitated magnesium hydroxide and calcium carbonate have settled, but
before filtration, the settled water is recarbonated to produce a pH of
about 8.7 so as to convert the residual calcium carbonate into the
soluble bicarbonate and prevent after-precipitation on the filter sand.
Normally, soda ash is added as needed to precipitate the non-carbonate
hardness, but due to the soda ash shortage, the West Des Moines plant
was using only a small quantity. The Webster City plantwas using lime
only during the August, 1974, survey but was using soda ash during the
February, 1975, resurvey.
A low magnesium content is desirable since precipitation of magnesium
hydroxide may occur within hot water heaters and be carried into hot
water lines and deposited there. In the single flocculation basin plant
complications arise since conditions for carrying out the precipitation
of calcium and magnesium vary in that different pH levels are needed for
each, about pH 9.5 for maximum precipitation of calcium carbonate and pH
10.5 for maximum precipitation of magnesium hydroxide.
More economical treatment can be provided by primary flocculation and
sedimentation with lime treatment to produce a pH of 10.6 to precipitate
the magnesium. The water is then recarbonated with carbon dioxide to
lower the pH to 9.4 and precipitate calcium carbonate in the secondary
basin with soda ash added as necessary to precipitate non-carbonate
hardness. In this procedure any soda ash required is added after re-
carbonation for because magnesium hydroxide precipitated in the
primary treatment absorbes an appreciable amount of negative ions thus
reducing the non-carbonate hardness. To obtain full effect of this
adsorption, soda ash is added after the magnesium hydroxide is settled.
Lime-soda ash-softening is aided by the use of alum, ferric sulfate,
sodium aluminate or polyelectrolytes to coagulate the fine crystals
formed by the softening reactions. The use of alum may form not alum-
inum hydroxide but magnesium aluminate so that the magnesium will be
113
-------
more effectively precipitated. High magnesium waters produce a sludge
containing a high proportion of magnesium hydrates which are lighter
than calcium carbonates.
- J . i
The suspended solids contact units employed by both the Webster City and
West Des Moines plants perform solids contact mixing, coagulation and
solids-water separation in a single package type basin. The suspended
solids contact action makes the units particularly adapted to calcium
carbonate precipitation. . The West Des Moines plant has a secondary
solids contact tank which was being used only for additional settling
due to an incrusted line between the two basins.
114
-------
SECTION 13.2
WEBSTER CITY
BACKGROUND DATA
Webster City is the county seat of Hamilton County in north central
Iowa and, with a 1970 population of 8,488, is the largest city in the
County. Hamilton County is primarily agriculturally oriented and the
county has shown a slight population increase during the past decade.
EXISTING WATER FACILITIES
Webster City presently derives its public water supply from two Jordan
aquifer wells constructed to a depth of 2005 feet. Both are pumped by
vertical turbine pumps with capacities of 850 to 950 gpm. The original
lime softening plant was constructed in 1949 and was enlarged to include
a second suspended solids contact softener in 1963. Treatment presently
consists of forced draft aeration, upflow clarification, recarbonation
and filtration.
Figure 37 is a flow diagram of the Webster City lime-soda ash softening
plant. Raw water from the two wells is pumped through a forced draft
aerator and flows directly to two parallel solids contact softeners.
One of the softeners is the older rectangular Permutit type contact
unit and the newer softener is a rectangular General Filter contact
unit. The design rate is 1,000 gpm for each unit with a total plant
capacity of approximately 2.9 million gallons per day. The clarifier
effluent then passes by gravity through a recarbonation basin to four
sand filters. Recarbonation is provided by a compressed C0« storage
tank. Finished water storage is provided by a clear well, 1,400,000
gallon surface storage reservoirs and elevated storage.
Lime sludge is discharged to two earthen settling basins located adja-
cent to the Boone River. The settling basins operate in series with the
supernatant from the second discharging to the river.
SOLIDS CONTACT SOFTENER AND FILTER PERFORMANCE
Two surveys were conducted at this public water supply to determine
treatment efficiencies when feeding lime alone and when feeding lime
plus soda ash to secure non-carbonate hardness removal with resultant
better radium and hardness removal. The August 13, 1974, plant survey
was conducted without soda ash being used as a part of the softening
process as a result of the shortage of soda ash. During early February
a supply of soda ash was obtained and the normal lime-soda ash treatment
process was being used at the time of the February 20, 1975, survey.
115
-------
Figure 37
Flow Diagram
Webster City
Lime-Sode Ash Softening Plant
Population 8,488 (1970)
August 13, 1974
Wei 1 No 1 No 5
Depth ft 2005 2005
Capacity 850 850
1700 gpm total pumpage
Parameter and
Removal Efficiency
-Well
Ra-226
pCi/1
6.1
Hardness
mg/I
507
Forced Draft Aerator
Chemical Dosages Ib/mg 8-13-74
Lime 1560 Soda Ash 0
Alum 0 Floe Aid 32 oz
Sol ids Contact No 1 No 2
Design - 1000 gpm
Volume - gal 72,000 91,000
Detention - Min 72 91
Surface area-sqft 750 930
Upflow rate -
gpm/sqft 1.25 1.25
•Clarifier Effluent
co2
Phosphate
C12
Filter
4 @ 16 x 14 - 224 sqft
Total 896 sqft
Filter rate 2.2 gpm/sqft
Backwash rate 15 gpm/sqft
No 1
1.9
68%
No 2
2.6
57%
No 1
333
322
No 2
282
43%
-Filter Effluent
Overal1 Removal
0.9
60%
85%
262
15%
48%
Clearwel1
and Ground Storage
700, 1000, 1000, 1300 gpm pumps
Distribution System
116
-------
Table 28 is a tabulation of the radiological and chemical analyses
performed on samples collected August 13, 1974 from the two wells and from
various stages in the process. Additional mineral analyses are shown in
Appendix A. Percentage removals of radium-226 and hardness for the
August 13, 1974, survey are also shown on the plant flow diagram, figure 37.
Table 29 is a similar tabulation of the radiological and chemical analyses
performed on samples collected during the February, 1975, survey.
Wells
Both of the 2,005 foot deep wells obtain water from the Jordan Sandstone
formation and both are pumped at an 850 gpm rate. There were considerable
variations in the radium and hardness characteristics during early pumping
periods and after extended pumping times. Wells 1 and 5 had radium-226
concentrations of 2.2 and 7 pCi/1 respectively after 30 minute pumping and
5.1 and 7.1 pCi/1 respectively, after a 6 hour pumping period. After
the longer pumping period the Wells 1 and 5 showed a hardness of 485 and
530 mg/1 respectively, and a total solids content of 685 and 1,010
respectively.
No weJ1 samples were collected during the follow-up survey on February 20,
1975, but it is assumed that the aerator effluent radium-226 and hardness
values of 7.8 pCi/1 and 482 mg/1 represented both wells.
Solids Contact Softening and Filtration
Table 30 lists the concentrations and percentage removals of the radium
and other chemical constituents through the system. Data for both the
August 13, 1974, and February 20, 1975, surveys are included in the table.
Generally, average values or representative sample values were used in
determining the percentage removals.
Radium-226
There were considerable variations in the radium removal data for clarifier
effluent during the August survey when lime alone was used for softening.
The radium-226 concentration was reduced from an average of 6.1 pCi/1 in
the well water to 1.9 and 2.6 pCi/1 in clarifiers 1 and 2 effluents
respectively. These are overall removals of 68 percent and 57 percent
respectively. Surprisingly, clarifier No. 1 which had the best radium
removal had the poorest hardness (32 percent) removal. There appeared to
be no apparent difference in chemical dosage or operation during the project
study.
117
-------
oo
Table 28
Radiological and Chemical Analysis
Webster City, Iowa Water Supply
August 13, 1974
Well #1
Well #1
Well #5
Well #5
Aerator
Aerator
Clarif i
Clarifi
Sampl i ng Po
2005' 25 min
2005' 6 hr
2005' 30 min
2005' 6 hr
Eff 30 min
Eff 5 hr
Gross
Alpha
int pCi/1
5.9
5.2
14
14
21
20
er #1 Eff 6 hr 4.4
er #1 Eff Dup 1.?
Clarifler #2 Eff 6 hr 2.4
-Clarif
-Clarif
-Filter
Filter
Filter
ier #1 Sludge
ier #2 Sludge
#4 Backwash
#2 Eff 5 hr
#4 Eff 5 hr
'-Clarif ier
''-Clarif ier
*F liter #4
Comp 1382
Comp R94
2 min 178
1.8
3.6
#1 Sludge
#2 Sludge
Backwash
Ra
226
pCi/1
2.2
5.1
7
7.1
5.9
6.8
1.9
1.3
2.6
1269
959
315
0.9
0.9
Hard- Total
ness Sol ids
mg/1 mg/1
560
485
450
530
475
510
332
334
282
260
264
Suspended
Suspended
Suspended
841
685
981
1010
941
971
809
801
751
95650
72282
7263
739
746
Sol ids
Sol ids
Sol ids
Al kal ini ty I ron
P
mg/1
0
0
0
0
0
0
18
13
18
42
32
94
71
6
T
mg/1
344
304
294
294
302
296
33
39
76
84
84
,950
,606
,500
pH Total
mg/1
7.1
7.5
7.0
7-3 0.69
7.5
7.75 0.64
10.0
10.1
10.1
9.3
9.3 0.02
mg/1
mg/1
mg/1
Sol Ca
mg/1 mg/1
130
120
120
0.69 110
120
0.64 110
69
69
49
35130
26500
2400
39
0.02 39
Mg Na Mn Cl
mg/1 mg/1 mg/1 mg/1
71
56
48
48 130 0.01 71
53
50 120 0.01 65
43
43
43
1610 114
1140 94
110 8
44
44 110 0.01 62
SO,
mg/7
320
390
400
380
390
390
390
380
400
1710
1650
150
390
370
-------
Table 29
Radiological and Chemical Analysis
Webster City, Iowa Water Supply
February 20, 1975
Gross Ra Hard- Total Alkalini ty
I ron
Sampl i ng Poi nt
Aerator Eff (2 wells)
Clarifier #1 Eff 8 hr
Clarifier #2 Eff 8 hr
Clarifier #1 Sludge Comp
Clarifier #2 Sludge Comp
Kilter #1 Eff
Filter #4 Eff 30 hr
Filter #3 BW Comp
Alpha
pCi/1
10
5.3
1.6
1200
2200
1.3
0.6
50
226
pCi/1
7-8
0.9
0.3
880
1000
0.3
0.3
50
ness
mg/1
482
150
150
186
106
3870
Sol ids
mg/1
977
758
767
106000
88900
793
725
4700
P
mg/1
0
54
54
36
34
32
T
mg/
296
80
82
104
94
86
pH Total Sol Ca
1 mg/1 mg/1 mg/1
7.8
10.95
10.95
10.95
10.85
9.9
9.85
9-7
0.56
0.03
0.0k
0. 12
0.05
4.9
110
34
34
34000
41000
43
13
1400
Mg Na Mn Cl SO^
mg/1 mg/1 mg/1 mg/1 mg/1
49
17
17
3400
4000
22
19
100
105000
88300
-------
Rectangular Solids Contact Unit
Figure 38
There was a considerable improvement in both radium removal and hardness
removal during the February, 1975, survey when both lime and soda ash
were used for softening. The wells have an average non-carbonate hard-
ness of over 180 mg/1 and residual hardness is high. Lime does remove
magnesium non-carbonate hardness but, for each molecule of magnesium non-
carbonate hardness removed, an equivalent molecule of calcium non-
carbonate hardness is formed.
During the February, 1975, survey the radium-226 concentration was
reduced from an average of 7.8 pCi/1 in the aerator effluent (from both
wells) to 0.9 and 0.3 pCi/1 in clarifiers No. 1 and 2 respectively,
even though hardness removals through the clarifiers were identical.
Clarifier No. 1 had the best radium removal but as noted had the poorest
removal on the previous survey. The two clarifiers had radium removals
of 88 and 96 percent respectively, which is a considerable increase over
the 68 and 57 percent radium removals on the previous survey when lime
alone was used.
Filtration through sand filters showing considerable calcium carbonate
encrustation effected some removal of radioactivity. Filter No. 4 is
newly rebuilt and was producing a turbidity of 2 turbidity units com-
pared with approximately 50 turbidity units in the Filter No. 1 effluent
with a very coarse encrusted media. Radium-226 concentration was re-
120
-------
duced from an average 2.2 pCi/1 in the clarifier effluent during the
August, 1974, survey to 0.9 pCi/1 in both filter effluents going to the
clearwell and distribution system. Likewise, during the February, 1975,
survey, the radium-226 concentration was reduced from an average of 0.6
pCi/1 in the two clarifier effluents to 0.3 pCi/1 in both filter efflu-
ents. The two filters achieved average radium-226 removals of
60 percent on the August, 1974, survey and 50 percent on the latter
survey.
TABLE 30
Radium-226, Hardness, Calcium, and Magnesium Removals
Solids Contact Softeners and Filtration
Webster City, Iowa
Sampling Point Radium-226
Hardness
Calcium
Magnesium pH
Percent
Percent Percent Percent
?Ci/l Removal Mg/1 Removal Mg/1 Removal Mg/1 Removal
August 13, 1974 (Lime - No Soda Ash)
Well
Clarifier #1 Eff.
Clarifier #2 Eff.
Filter #2 Eff.
Filter #4 Eff.*
Overall
6.1
1.9
2.6
0.9
0.9
0.9
68
57
60
60
85
507
333
282
260
264
262
32
43
15
15
48
120
69
49
39
39
39
42
29
20
20
68
February 20, 1975 (Lime-Soda Ash)
Aerator Eff.
Clarifier #1 Eff,
Clarifier #2 Eff.
Filter #1 Eff.
Filter #4 Eff.*
Overall
*Low turbidity from this filter.
7.8
0.9
0.3
0.3
0.3
0.3
88
96
50
50
96
482
150
150
186
106
106
69
69
—
29
78
110
34
34
43
13
13
69
69
—
69
85
50
43
43
44
44
44
49
17
17
22
19
19
7.4
14 10.0
0 10.1
0 9.3
0 9.3
14
7.8
65 10.95
65 10.95
— 9.9
— 9.85
61
The overall radium-226 reduction was 85 percent with lime softening
(pH-10.1) and 96 percent with lime-soda ash softening (pH-10.95) with
effluent concentrations of 0.9 and 0.3 pCi/1 respectively.
Hardness
Table 30 indicates much higher hardness removals were accomplished with
the lime-soda ash chemical treatment during the February, 1975, survey.
During the August, 1974, survey, hardness was reduced from an average
121
-------
hardness of 507 mg/1 in the well water to values of 333 and 282 mg/1 in
the clarifier No. 1 and 2 effluents. These are unit removals of 32
percent and 43 percent respectively. This compares with the February
survey which showed hardness reductions from 482 mg/1 in the aerator
effluent (two wells) to 150 mg/1 in both clarifier effluents for a 69
percent removal.
During the August, 1974, survey, hardness was reduced from an average
307 mg/1 to 260 and 264 mg/1 in the two filters for a process hardness
removal of 15 percent. During the February, 1975, survey the No. 1
filter which was encrusted showed an actual hardness and some other
chemical constituent increases. The No. 4 filter which produced a
relatively turbidity-free effluent showed a reduction in hardness and
other chemical constituents for a hardness removal of 29 percent. The
overall hardness reduction through all units was 78 percent with a final
hardness of 106 mg/1.
Calcium decreased from 120 mg/1 to 39 mg/1 following the lime treatment
process and from 110 mg/1 to 13 mg/1 with the lime-soda ash treatment
process. Magnesium showed a small increase with the lime treatment
process and decreased from 49 mg/1 to 19 mg/1 with lime-soda ash treat-
ment for an overall reduction of magnesium of 61 percent.
RADIUM-226 MATERIAL BALANCE
Figure 39 is a schematic drawing showing water treatment units and the
radium-226 activity at various stages in the treatment process. The
data is from the August 13, 1974, survey when lime alone was used for
treatment. Detailed computations are shown in Appendix B.
Applying the average 6.1 pCi/1 concentration value to the well pumpage
of 1.32 million gallons for the daily pumpage gives a total radium
activity of 30.6 uCi in the well pumpage. Settling of the coagulated
and softened water in the solids contact softener (upflow clarifier)
reduced the radium-226 concentration in the clarifier effluent to 2.2
pCi/1. It was impossible at the time of the survey to accurately measure
the timed continuous sludge blowoff. Consequently, the radioactivity in
the sludge drawoff was calculated from the estimated solids removal in
the softening process. The average 1,114 pCi/1 radium concentration
applied to the calculated gallons of lime sludge gave a radium-226
radioactivity of 24.6 uCi in the sludge drawoff.
Backwash of the sand filters contained a radium concentration of 92
pCi/1, which applied to the average quantity of backwash water for the
day, produced a radium-226 radioactivity of 5.6 uCi prorated for the
daily pumpage. Subtracting the radioactivity removed by the lime
sludge drawoff and filter backwash from the total well radioactivity
leaves a difference of 0.4 uCi radioactivity compared with the value of
122
-------
4.4 uCi in the sand filter effluent. Flow lost by filter backwash was
not considered in the sand filter effluent flow computation. This is
not a good material balance through the treatment system.
Similar computatons and schematic drawing (Figure 40) were also devel-
oped for a plant study in February, 1975, when lime and soda ash were
used as softening chemicals. A higher radium removal is evident from
the higher (32.6 nCi) radioactivity in the sludge drawoff on the later
survey. Likewise, the better removal is evident in the much lower total
radioactivity (2.7 and 1.36 iiCi) in the clarifier effluent and filter
effluent with the lime-soda-ash softening.
123
-------
Figure 39
Ra-226 Distribution in Treatment Process
Webster City, Iowa
Lime-Soda Ash Softening Plant
August 13,
Remova1s
Thru
Unit
uCi
30.6
-5.6
0.4
by difference
Unit
Effluents
uCi
I3Q.6 Me? r
6.1 pCi/1
No
:iari
fier
11.2
2.2 pCi/1
Average
gCi
0.9 pCi/1
|30.6 uCi I Tota1
l3 M I Radioactivity
6.1 pCi/1 Activity
Well one day pumping 8-13-74
1.32 Million Gallons
-------
Remova1s
Thru
Unit
uCi
-32.6
2.8
-0.26
2.5**
Legend
Figure kQ
Ra-226 Distribution in Treatment Process
Webster City, Iowa
Lime-Soda Ash Softening Plant
February 20, 1975
Unit
Effluents
uCi
| 35.A uCi }-
7.8 pCi/1
No 1
Clarifier
J2.72 MCi
0.6 pCI/1
{1.36 uCt
0.3 pCI/1
MCi]
I
pCi/
TP$9l . .
Radioactivity
_
7.a pCi/I Activity
Well one day pumping
1.20 MGD Flow
S
No 2
Harifier
1 udqe
1
drawoff
32.6
980 pCi/1
k Sand Filters
Prorated flow
Filter
Backwash
I, ., ".
'°'26 ^Cl J
50 pCI/1
Distribution
System
125
-------
SECTION 13.3
WEST DES MOINES
BACKGROUND DATA
West Des Moines, located at the western edge of Polk County adjacent to
the City of Des Moines is a rapidly growing community with a 1970
population of 16,441 as compared with a 1950 population of 5,615.
Present population is estimated at over 20,000.
EXISTING WATER FACILITIES
West Des Moines presently derives its water supply primarily from two
Jordan aquifer wells and from eight shallow gravel pack wells averaging
42 feet in depth. During past years an average of over one million gal-
lons per day has been purchased from a nearby cement plant which has a
Ranney collection well about a mile from the water treatment plant. The
primary source during the study was the two Jordan wells 2,460ft and
2,480 ft in depth and pumping at about 1,100 gpm each. The water table
from the Jordan sandstone formation has dropped over 60 feet during the
past year.
Figure 41 is a flow diagram of the West Des Moines lime-soda ash soften-
ing plant. The plant originally was an iron removal plant serving the
shallow wells, softening was added in 1962 and the plant capacity en-
larged in 1972. Raw water from the two deep wells used during the
survey is pumped to a forced draft aerator and flows by gravity through
the suspended solids contact softeners, recarbonation basins and sand
filters.
SOLIDS CONTACT SOFTENER AND FILTER PERFORMANCE
The West Des Moines lime-soda ash solids contact units (figure 42), designed
for series •oration, could not be used in this manner at the time of the
survey due to an encrusted line between the contact units. The second
solids contact tank was being used primarily for additional settling
time for a portion of the treated flow. In addition, due to limited
availability of soda ash, very little was used for non-carbonate hard-
ness removal.
Table 31 is a tabulation of the radiological and chemical analyses
performed on the two deep wells utilized during the survey and from the
various stages in the process. Additional mineral analyses
are shown in Appendix A. Percentage removals of radium-226 and hard-
ness are also shown on the plant flow diagram, Figure 41.
126
-------
5-10'xl2'
4-I2'xl8'
Figure 4l
Flow Diagram
West Des Moines, Iowa
Lime-Soda Ash - Softening Plant
Population 16,440 (1970)
Wells No 1 No 2
Depth 2460 2480
Capacity 1025 1100 gpm
Total Capacity 2100 gpm
Parameter and
Removal Efficiency
Ra-226 Hardness
pCi/1 mg/J'
-Well
Forced draft aretor
Chemical dosages Ibs/MG
Lime V710 Soda Ash 220
-Alum 100 Floe Aid 1 mg/1
9-3
376
Solids Contact Units
Design
Detention 2 hrs @ 2450 gpm
Upflow rate 1.0 gpm/sqft
Bypass 1100 gpm (Estimate)
•Contact Effluent
2.6
72%
C02 Basin
9 Sand Filters
5 @ 600 sqft 4 @ 636 sqft
Filter rate 2.65 gpm/sqft
Backwash 2200 gpm
215
433
Clear Well
168,000 gal
2-1500 gpfn pumps
2-2500 gpm pumps
Ground Storage
1,000,000 gal
1500 2500 3000 gpm
Distribution System
•Filter Effluent
Overall Removal
2.35
10%
752
190
12%
50%
-System 1.9
168
127
-------
KJ
OO
Table 31
Radiological and Chemical Analysis
West Des Moines, Iowa Water Supply
August 1, 1974
Gross Ra Hard- Total Alkalini ty
I ron
Sampl ing Point
Well #1 12 hr
Well #2 12 hr
Clarifier #1 Inf 0 hr
Clarifier #1 Inf 12 hr
Clarifier #1 Eff 8 hr
Clarifier #1 Eff 12 hr
Clarifier #1 Eff Dup
Clarifier #2 Eff 3 hr
*Clarifier #1 Sludge
New Filter Eff 8 hr
New Filter Eff 12 hr
-Filter #4 Backwash 2 min
'•Filter #4 Backwash Comp
Alpha
pCi/1
26
2k
29
29
5.0
7-3
6.5
3.4
3312
7-1
8.1
33
19
226
pCi/1
9.6
11
8.6
10
2.9
2.6
2.1*
2.8
2300
2.4
2.3
12
6.3
ness
mg/1
376
372
376
376
242
183
192
183
192
455
410
Sol ids
mg/1
1200
1200
1210
1180
1063
1030
1019
145500
1030
1010
1278
1273
P
mg/1
0
0
0
0
52
56
50
46
30
48
48
T pH Total
mg/1 mg/1
260 7.5 0.36
258 7.5 0.33
264 8.0
260 8.0 0.25
84 10.1
80 10.4 0.03
78 10.2
96 9.35
90 9-5 0.01
144 9.55
132 9.6
Sol Ca
mg/1 mg/1
0.36 87
0.33 88
88
0.25 88
49
0.03 33
36
50470
31
0.01 31
130
110
Mg
mg/1
40
40
40
40
31
27
27
3750
28
27
40
38
Na
mg/1
250
250
250
260
240
Mn
mg/1
<0.01
0.01
0.01
0.01
0.01
Cl
mg/1
65
67
65
66
68
so4
mg/1
550
570
580
570
570
580
570
4760
560
590
570
570
Distribution System
5.4 1.9 168 951 48 80 9.7
28 26
520
"Clarifier #1 Sludge Comp
'"'Filter #4 Backwash 2 min
*Filter #4 Backwash Comp
Suspended Sol ids 144,200
Suspended Solids 126
Suspended Sol ids 222
-------
Solids Contact Softeners
Figure 42
Wells
Both of the deep wells, 2,460 ft in depth, were sampled after twelve hours
of continuous pumping. Wells Nos. 1 and 2 had radium-226 concentrations
of 9.6 and 11 pCi/1 respectively, while the following similar chemical
characteristics were registered: hardness 374 mg/1, total solids 1,200
mg/1, calcium 88 mg/1, magnesium 40 mg/1 and sodium 250 mg/1.
Solids Contact Softening and Filtration
Table 32 lists the concentrations and percentage removals of radium and
chemical constituents.
Radium-226
Radium-226 concentration was reduced from an average 9.3 pCi/1 in the
clarifier No. 1 influent to an average value of 2.6 pCi/1 in the clari-
fier effluent for an average radium removal of 72 percent. One sample
collected from the clarifier No. 2 (secondary) effluent receiving a
portion of settled No. 1 effluent showed no additional radium removal.
129
-------
TABLE 32
Radium-226, Hardness, Calcium, and Magnesium Removals
Solids Contact Softeners and Filtration
West Des Moines, Iowa
August 1, 1974
Sampling Point Radium-226
Hardness
Calcium
Magnesium
Percent
Percent Percent Percent
>Ci/l Removal Mg/1 Removal Mg/1 Removal Mg/1 Removal
Well Supply
Clarifier #1 Eff.
Filter Eff.
Overall
System
9.3
2.6
2.35
72
10
75
376
215
190
43
12
50
88
33
31
62
6
65
1.9
168
28
40
27
27
26
32
0
35
A sand and anthracite filter sampled at 8 hours and 12 hours after back-
wash showed a slight additional average radium-226 removal to 2.35 pCi/1
for an additional 10 percent radium removal by filtration of calcium
carbonate and other solids from the clarifier effluent. This filter
with the anthracite media for some reason was permitting turbidity to
pass through the filter. The 1.9 pCi/1 radium concentration shown for
the distribution system indicates that other filters may be more effi-
cient or solids are settling in the clear well or other surface storage
basins.
An overall radium-226 removal of 75 percent was accomplished by the
softening process using lime and a small amount of soda ash.
Hardness
Hardness was reduced from an average of 376 mg/1 in the clarifier influ-
ent to values of 242 and 188 mg/1 in the clarifier No. 1 effluent at 8
hour and 12 hour intervals after starting operation for the day. There
is an average unit removal of 43 percent with a maximum removal of 50
percent utilizing the lowest clarifier hardness value. Due to extremely
hot weather during the sampling period, water consumption was at a high
rate and the solids contact unit flow rates were near the maximum.
The average clarifier effluent hardness value of 215 mg/1 was reduced in
the filter effluent to 190 mg/1 for an additional removal of 12 percent.
Clarifier hardness samples collected after the longer operating times
indicate little hardness removal was taking place due possibly to tur-
bidity passing through the filter. The overall hardness reduction
through all units was 50 percent with a final hardness of 190 mg/1 in
the filter effluent although the system hardness was 168 mg/1. Calcium
decreased from 88 mg/1 to the range of 30 mg/1 following the lime
softening process. Magnesium reduction was from 40 mg/1 to 27 mg/1.
130
-------
RADIUM-226 MATERIAL BALANCE
Figure 43 is a schematic drawing showing the process units and the
radium-226 radioactivity at various stages in the treatment process.
The detailed computations are shown in Appendix B.
Applying the average 9.3 pCi/1 concentration value to the daily well
pumpage of 2.57 million gallons gives a total radium-226 radioactivity
of 91 yCi in the well pumpage. Settling of the coagulated and softened
water in the suspended solids contact softeners reduced the radium con-
centration to 2.6 pCi/1 and radioactivity of 24.6 uCi in the clarifier
effluent. It was impossible at the time of the survey to accurately
measure the timed continuous sludge blowoff. The sludge pumps were
replaced at a later date. Consequently, the radioactivity in the sludge
drawoff was calculated from the estimated solids removal by the chemical
dosages in the softening process. The average 2,300 pCi/1 radium-226
concentration in the 14.5 percent dry weight solids sludge applied to
the calculated gallons of lime sludge gave a radium-226 radioactivity of
76.0 uCi in the sludge drawoff.
Backwash of the sand filter contained a radium concentration of 6.3
pCi/1 which applied to the 1.2 percent backwash quantity for the day
produced a radium-226 radioactivity of 0.7 uCi for the daily pumpage.
It will be noted the filter backwash radium-226 concentration is very
low and apparently little removal of suspended solids from the clarifier
effluent was taking place in the sand filter. Likewise, the radium
concentration of 2.6 pCi/1 in the clarifier effluent was reduced very
slightly to 2.3 pCi/1 in the filter effluent. This is a poor removal of
radioactivity by filtration as compared with the much higher removal in
one of the Webster City filters. Unfortunately the filter selected was
a dual media filter which apparently has a coarse media permitting tur-
bidity to pass through in the effluent. Radioactivity present in the
suspended solids thus is not removed by the filter.
Subtracting the radioactivity removed by the lime sludge drawoff and
filter backwash from the total well water radioactivity leaves a differ-
ence of 14.3 uCi compared with the value of 22.6 iiCi contained in sand
filter effluent. Flow lost by filter backwash was not considered in the
flow computations. Considering the unavailability of good sludge draw-
off flow data, this is a fair material balance through the treatment
system.
131
-------
Removal
Thru
Unit
uCi
91
-76.0
15.0
Figure 43
Ra-226 Distribution in Treatment Process
West Des Moines, Iowa
Lime-Soda Ash Softening Plant
-0.7
by difference
Legend
91 uCi
Unit
Effluents
uCi
I 911 uCI |-
9.3 pCi/1
24.6
2.6 pCi/1
[22.6 uC? \-
»•— — ^— ^
2.3 pCi/1
Total
Radioactivity
9-3 pCi/1 Concentration
Wei 1 one day pumpage
2.57 MGD
2.57 MGD
Solids
Contact
Lime
Sludge
Drawoff
•j 76.0 uCi
2300 pCi/1
Sand Filter
Filter
Backwash
I 0.7 uCi \
6.3 pCi/1
30,000
gallon
backwash
Distribution
System
132
-------
SECTION 14
COSTS OF TREATMENT
COSTING PROCEDURES
The annual cost of operating and maintaining a water treatment facility
consists of six- components:
Capital Cost Amortization
Operation Labor
Maintenance Labor
Maintenance Materials
Chemicals
Power
The capital cost invested in a water treatment facility is ordinarily
amortized over a period of twenty years at a recovery rate sufficient to
cover the cost of bond retirement by the owners of the facility. As an
example, a capital cost of debt could be retired over a twenty-year
period at 6 percent or an annual recovery factor of 0.0726. All equip-
ment costs, construction costs, and engineering are usually combined to
give the capital construction cost.
There are no national guidelines as to the level of operational and
maintenance labor required for a water treatment plant to produce a
safe, potable water on a continuous basis. Such labor costs vary
greatly with the type of treatment, necessary operating and laboratory
control, competence of designer, age of facility and many others.
Maintenance supplies such as equipment parts, laboratory supplies and
other expendables depend on the maintenance philosphy of the plant and
municipal officials and the level of technical expertise of the oper-
ating personnel.
Electrical power requirements vary greatly with initial well pumping and
repumping head requirements. Thus a power requirement in terms of
kwhr/kgal of treated water would be difficult to calculate. Electric
power costs would also be based on local user rates.
Chemical cost for the principal softening chemicals such as salt, lime
and soda ash is dependent on the amount and type of hardness. There are
also chemicals needed for coagulation, pH adjustment during the soften-
ing process, pH adjustment for protective calcium carbonate deposition
and disinfection.
It was impossible to obtain accurate data on the construction cost at
many municipalities included in the study due to the age of some of the
treatment plants or continuing additions and improvements to the treat-
133
-------
ment process or treatment plant. Some of the treatment plants are over
thirty years old and records of treatment plant construction costs are
no longer available.
ANNUAL COSTS
Section 11.25 of the Code of Iowa requires an annual report of the
financial transactions and balances of the cities and towns in Iowa be
furnished to the Auditor of State. Included in this report of municipal
finances is a tabulation of the waterworks utility receipts and expens-
es, with the latter including plant operation and maintenance, distri-
bution operation and maintenance, accounting and collection, debt
service, capital outlay, and several miscellaneous items.
From these state auditor reports, the cost of producing water for each
year can be calculated. Unfortunately, the capital cost for the indi-
vidual treatment process cannot be determined readily due to inclusion
of water distribution and well costs, accounting and the debt service
in addition to the capital outlay costs. Separation of the distribution
system and well costs from the municipal records was not practicable in
the time period for the study. Tables included in Section C of the
Appendix tabulate the total expenses, including plant operation and
maintenance, distribution operation and maintenance, accounting and
collection, debt service, capital investment and miscellaneous costs of
the systems studied. Distribution costs were high in some of the smal-
ler towns due to extensive water main extensions.
Table 33 summarizes a comparison of the total annual capital and opera-
tion costs and the plant operation and maintenance costs in C/1,000 gal.
for one representative year of the three years tabulated on the Tables
in the Appendix. This summary shows high annual water costs with a
range from a low of 44c/l,000 gal. for the City of Grinnell to a high of
1320/1,000 gal. for the Town of Adair. Grinnell is one of the larger
cities, but the annual cost for the following year increased to
77<:/l,000 gal. when a capital cost of $317,000 for a new Jordan well was
added to the water financing program. The annual cost for Adair reached
a high of 143<:/1,000 gal. during one year due to the cost of a water
main extension to an industrial area and a housing subdivision.
Suprisingly, the annual costs of the two iron removal plants, Adair and
Stuart, were higher than the zeolite softening plants which generally
also used iron removal as pretreatment preceeding the ion exchange
process. These two plants are among the smallest of the treatment
plants and unit costs would be higher in the case of the smaller plants.
Figure 44 shows the design plant capacity plotted against the annual and
plant operation and maintenance costs in c/1,000 gallons. The City of
134
-------
Table 33
OJ
Ui
Comparison of Annual Capital and Operation Costs and Plant O&M Cost (I)
C/1000 gal
Plant Annual
Total Cost Range of
0&M Cost
1970
Municipality Population Treatment
Reverse Osmosis
Greenfield
1 ron Remova 1
Adair
Stuart
Zeol ite Softening
El don
Esthervi 1 le
Grinnel 1
Holstein
Lime Softening
Webster City
West Des Moines
2212
750
1354
1319
8108
8402
1445
8488
16441
RO
Greensand
Aer-IR
IR-Zeo
IR-Zeo
Aer-Zeo
1 R-Zeo
Lime-SA
Lime-SA
Capacity Pumpage
MGD MG/yr Amount
0.22
0.16
0.43
0.28
1.2
1.5
0.32
25
35
20(2)
24.5
56.3
36.9
408
416
51.6
507
613
$ 46,944
32,358
40,944
23,886
199,614
185,101
29,112
269,898
(6)
Costs
C/1000
10U
132
73
65
57
44
5,9
53
Costs
C/1000
91-111
143(3)
64-79
59-91(4)
44-66
77(5)
72
53-64
Costs
Amount £/1000
$ 4,737
11,243
6,726
10,909
7,793
95,737
17,170
104,613
124,868
23*
45
12
30
26
23
33
21
20
(1) Based on recent representative year
(2) Reverse Osmosis used to supplement surface water supply
(3) High costs due to water main construction
(4) Capital cost increase due to new salt storage facilities
(5) $317,000 capital cost for new Jordan well
(6) Not tabulated; extreme costs due to plant improvement costs
-------
West Des Moines was not included in the total annual cost in view of an
extreme increase in annual costs due to the inclusion of capital cost
items for a large plant improvement during this period.
Figure 44 indicates the grouping of the 3 larger cities in the study in
the 50-60<:/1,000 gal. annual cost range and the grouping of the smaller
plants in the higher 60-132c/l,000 gal. annual cost range. Major por-
tions of the three larger plants were constructed 20-25 years ago and
capitalization costs would be relatively low. Likewise, major portions
of all of the other smaller plants, with the exception of the Greenfield
reverse osmosis plant, were also constructed 10 or more years ago.
PLANT OPERATION AND MAINTENANCE COSTS
The plant operation and maintenance costs are tabulated in Table 33 and
shown in Figure 44. These costs were taken from the representative
year data given in the municipal cost data in Section C of the Appendix.
The operation and maintenance (0 & M) costs for Greenfield in the
23c/1,000 gal. range may be low since the plant is located in the base-
ment of the surface water plant and the generally limited need for
operating time is handled by the surface water plant operator. Membrane
replacement costs over a period of time which are considered maintenance
costs are not included in these costs.
The two iron removal plants show the highest and lowest 0 & M costs of
the treatment plants surveyed. Adair has the smallest population and
had extensive maintenance on the greensand filter during the period. On
the other hand, the Stuart iron removal plant is located adjacent to the
power plant and personnel can be used more effectively in the combined
systems.
In the zeolite softening plants the two larger plants have the lower 0
& M cost of 23 and 26c/l,000 gal. compared with the smaller plant values
of 30 and 330/1,000 gal. In spite of the higher 0 & M costs, the smal-
ler plants were not receiving the same degree of good operation and
maintenance as the larger plants due to other necessary routine work
outside the treatment plant in the smaller towns.
The 0 & M costs for the lime-soda ash plants were the lowest, being in
the 20 to 21<:/1,000 gal. range. Both are in the same range in spite of
the larger population for West Des Moines. Maintenance may be lower
than normal at Webster City, in view of planning for a new softening
plant at a different site.
136
-------
-p
en
O
u
C
O
-H
-P
03
4J
•H
U
-P
w
o
U
2
j '-a M
<8
O Cn
-P o
C O
nj o
r-l »
CM -H
\
-H O
(fl
3
C
c
-l
tO 0)
-p a
0 0
E-t
„!;
cu o
en
tn
O
Plant Capacity MGD - 100% Factor
O Reverse Osmosis
I Iron Removal Only
X Ion Exchange
• Lime Softening
COST COMPARISON
A search of the literature indicated a considerable number of studies
showing cost data for plant and operation data for the various types of
treatment processes. Attempts were made to correlate replacement costs
or operation costs with Iowa data with poor success. Wood ^ reports
cost data for lime-soda ash treatment and zeolite softening which indi-
cates that zeolite softening plants are more economical up to a capacity
of about 4 mgd and that lime-soda ash plants are more economical above
this capacity. However, this data does not include labor costs or
pretreatment. Data on cost of ion exchange treatment are reported by
Faber, et al. Other studies are also reported by Miller, Bresler
and Miller 29 and Mattson 30.
137
-------
o-i
A manual Ji for calculation of costs of conventional water treatment
costs was prepared for the Office of Saline Water. Applying the cost
graphs and other cost data to two Iowa plants, Adair and Webster City,
resulted in much lower computed total costs as compared with the actual
auditor reports. The permanganate system, site preparation and building
costs for Adair were computed at $43,000 which amortized to $3,750 per
year and added to computed 0 & M labor costs of $3,000 gave total annual
cost of $6,750. This converted to an annual cost of 27
-------
SECTION 15
ACKNOWLEDGEMENTS
The project was initiated by Keith Bridson, P.E., Chief, Permits Branch,
Water Quality Management Division, Iowa Department of Environmental
Quality. The assistance and visits to the project of Project Officer
William L. Brinck, Assistant Chief for Nuclear Engineering, Radiochemis-
try and Nuclear Engineering Branch, U. S. Environmental Protection Agency,
Cincinnati, Ohio, are gratefully acknowledged.
Most of the laboratory work was performed by the Branch Lab. of the
State Hygienic Laboratory in Des Moines under the general direction of
Dr. R. L. Morris, Ph.D., and Roger Cochran, Health Physicist. The lab-
oratory work was actually performed by or under the direct supervision
of the following personnel of the Des Moines Branch: Ray Pierson, Daryl
W. Ebert and Arnolds Abele.
The contributions in various ways of the following are appreciated:
Keith Bridson, P.E., Chief, Permits Branch, Water Quality Management Div.
Paul J. Horick, Chief, Groundwater Geology, Iowa Geo. Survey
Neil B. Fisher, Environmental Engineering Consultant, University of Iowa
Gary S. Logsdon, Research Sanitary Engineer, EPA Water Supply Research
Laboratory, Cincinnati
Merlin Anderson, President, General Filter Company
Water Superintendents:
Greenfield - Kenneth Hoadley
Adair - Roger Tibben
Stuart - Norral Smith
Eldon - N. C. Garrett
Estherville - R. W. Twigg
Grinnell - Tom Anderson
Holstein - Charles Reiss
Webster City - Ronald Keigan
West Des Moines - Henry Falcon
139
-------
SECTION 16
REFERENCES
1. Lucas, H. F. and Ilcewicz, F. H. Natural Radium-226 Content of
Illinois Water Supplies. Journal American Water Works Association.
50:1523-1532. November, 1958.
2. Morris, R. L. and Klinsky, J. W. Radiochemistry and Removal Char-
acteristics of Radium Isotopes in Iowa Well Water Proceedings, Iowa
Academy of Sciences. 62:62-63. 1962.
3. Ball, A. D. Letter of September 4, 1964, addressed to Mr. Norman
Petersen, Project Director, Midwest Environmental Health Study.
Subject: Protocol for Plan of Study of Causes of Variability in
Radium Concentration in Municipal Water Systems. State Hygiene
Laboratory, Medical Laboratory Building, State University of Iowa,
Iowa City, Iowa.
4. State Hygienic Laboratory, State University of Iowa, Radium Concen-
trations in Public Water Supply in Iowa Communities. Issued in 1964
by the Iowa State Hygienic Laboratory in cooperation with the U.S.
Public Health Service, Iowa City, Iowa.
5. Lucas, H. F., Jr. Study of Radium-226 Content of Midwest Water
Resources. Radiological Health Data. 2:400-401. 1961
6. Public Health Service Drinking Water Standards, 1962. Public Health
Service Publication No. 956, U.S. Department of Health, Education
and Welfare, Washington, D.C.
7. Petersen, Norman J., Samuels, Larry D., M.D., Lucas, Henry F. and
Abrahams, Simon P., M.D. An Epidemiological Approach to Low-Level
Radium-226 Exposure. Public Health Reports. 81(9):805-814.
September, 1966.
8. Petersen, Norman J. and Samuels, Larry D. Deciduous Teeth an
Indication of Radium-226 Exposure. Health Physics, Permagon Press.
9. Symons, J. M. and Robeck, G. C. Treatment Processes for Coping with
Variation in Raw Water Quality. Journal American Water Works
Association. 67:142-145. March, 1975.
10. Winton, Elliot F. and McCabe, Leland J. Studies Relating to Water
Mineralization and Health. Journal American Water Works Associa-
tion. 62:26-30. January, 1970.
140
-------
11. Schroeder, H. A. Degenerative Cardiovascular Disease in the Orient
II. Hypertension. Journal Chronic Diseases. 8:312. 1958.
12. Schroeder, H. A. The Water Factor. New England Journal Medicine.
280:836. 1966.
13. Neri, L. C., et al. Health Aspects of Hard and Soft Waters.
Journal American Water Works Association. 67:403-409, August, 1975.
14. Schroeder, W. A., Nason, A. P., Tipton, J. H. and Balassa, J. J.
Essential Trace Metals in Man. Journal Chronic Diseases. 20:179.
1967.
15. Fact Sheet. National Survey of Drinking Water for Sodium Content.
Prepared by Division of Chronic Diseases, Heart Disease Control
Program, U.S. Department of Health, Education and Welfare. May,
1963.
16. Laubusch, Edmund J. and McCammon, Charles S. Water as a Sodium
Source and its Relation to Sodium Restriction Therapy Patient
Response. American Journal of Public Health. 45:1337-1343.
October, 1955.
17. Steinhilber, W. L. and Horick, P. J. Water Resources of Iowa.
Symposium sponsored by Iowa Academy of Science. 29-67. 1969.
18. Lynch, M. A., Jr. and Mintz, M. S. Membrance and Ion Exchange
Procedures - A Review. Journal American Water Works Association.
64:711-725. November, 1972.
19. Moore, D. H. Operation of Reverse Osmosis Desalting Plant at
Greenfield, Iowa. Journal American Water Works Association.
64:781-783. November, 1972.
20. Why Hollow Fiber Reverse Osmosis Won the Top C E Prize for Du Pont.
Chemical Engineering. 78:54-59. November, 1971.
21. Olson, Larry L. and Twardowski, Jr., Charles J. FeC03 vs Fe(OH)3
Precipitation in Water Treatment Plants. Journal American Water
Works Association. 67:150-153. March, 1975.
22. Water Conditioning Handbook. The Permutit Company. 1954. p 10/1
23. Bowers, Eugene. Ion-Exchange Softening. Chapter 10. Water Quality
and Treatment. Handbook prepared by American Water Works Associa-
tion. Third Edition - 1971.
141
-------
24. Aultman, William W., Haney, Paul D. and Hall, Harry R. Disposal of
Water Purification and Softening Plant Works. Brine Disposal from
Sodium Zeolite Softeners. Journal American Water Works Association.
39:1215-1219. December, 1947.
25. Committee Report. Disposal of Water Treatment Plant Wastes.
Journal American Water Works Association. 64:814-819. December,
1972.
26. Wood, Frank 0. Selecting a Softening Process. Journal American
Wastes Association. 64:820-824. December, 1972.
27. Faber, Harry A., Bresler, Sidney A., and Walton, Graham. Improving
Community Water Supplies with Desalting Technology. Journal
American Water Works Association. 64:705-710. December, 1972.
28. Miller, E. F. Desalting as a Source of Water Supply. Journal
American Water Works Association. 64:804-807. December, 1972.
29. Bresler, Sidney A. and Miller, Edward F. Economics of Ion-Exchange
Techniques for Municipal Water Quality Improvements. Journal
American Water Works Association. 64:764-772. November, 1972.
30. Mattson, Melvin E. Membrane Desalting Gets Big Push. Water and
Wastes Engineering, pages 35-42. April, 1975.
31. Watson, I. C. Study of Feasibility of Desalting Municipal Water
Supplies in Montana. Manual for Calculation of Conventional Water
Treatment Costs. Office of Saline Water, Washington, D.C. March,
1972.
142
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Alkalinity
Amortization
Anion
Aquifer
Backwash
Bed Depth
Blending
Bed Volume
Breakthrough
Brine
SECTION 17
DEFINITIONS
Capacity to neutralize acids. In water, most
alkalinity is due to the content of bicarbonates,
carbonates, or hydroxide. The alkalinity is
normally expressed in terms of calcium carbonate
equivalents.
The uniform annual payment for the prescribed
loan period to retire the capital debt obliga-
tion. Equal annual payments generally represent
declining interest and increasing principal
payments over the life of the debt.
An ionic particle which is negatively charged.
A geologic formation, a group of formations, or
a part of a formation that is water-bearing; the
term is usually limited to those units capable
of yielding water in sufficient quantity to
constitute a usable supply.
Reverse (normally upwards) flow through a bed of
mineral or ion exchange resin to remove insoluble
particulates and to loosen the bed.
The height of mineral or ion exchange resin in a
column.
Mixing of softened water from an ion exchange
plant with unsoftened water to obtain a desired
hardness content.
The amount of mineral or ion exchange resin, in
a column.
Refers to the concentration of a particular ion
or hardness in the effluent from a treatment
system. Breakthrough occurs when the effluent
concentration rapidly increases. Normally, when
the breakthrough concentration reaches about 10%
of the influent concentration, exhaustion has
occurred.
Saturated or diluted solution of salt (NaCl)
used in chemical process of replacing sodium
ions removed during the ion exchange process.
143
-------
Capacity
Cation
Composite Sample
Curie (Ci)
Downflow
Endpoint
Formation
gPg
Grains Per Gallon
Grain
gpcpd
gpm
gpm/cu ft
gpm/sq ft
Gross Alpha Particle
Activity
The quantitative ability of a treatment compo-
nent or system to perform. With ion exchange
systems, this quantity is expressed as kilograins
per cubic foot.
An ionic particle which is positively charged.
A sample collected to be representative of a
water flow which continues for an extended
period of time.
The unit of quantity of radioactivity, the curie,
is defined as 37 billion nuclear transformations
per second.
Direction of flow of solutions through ion
exchange or mineral bed colums during operation;
in at the top and out at the bottom.
The achievement of exhaustion. With ion
exchange resins, the endpoint of the softening
cycle is considered at 10% breakthrough.
The function of a process component in the ser-
vice cycle. The regenerated form of a weak base
resin without adsorbed acids.
A unit of concentration (weight per volume) that
is used in the ion exchange industry. (See
"Grain".) One gpg is numerically equal to
17.1 mg/1.
A unit of weight, being numerically equal to
l/7000th of a pound. (See "Grains Per Gallon".)
Gallons per capita per day, a measure of water
consumption in municipalities.
Gallons per day.
Gallons per minute.
Gallons per minute per cubic foot of ion exchange
resin or other mineral.
Gallons per minute per square foot of cross-
sectional area.
This means the total radioactivity due to alpha
particle emission.
144
-------
Hardness
ion
Ion Exchange Resin
kgr
Kilograins
kgr/cu ft
Leakage
Lime
Material Balance
mgd
Microcurie
mg/1
Milligrams Per Liter
pCi/1
Picocurie Per Liter
The sum of the calcium and magnesium ions,
although other polyvalent cations are included
at times. Hardness is normally expressed in
terms of calcium carbonate equivalents.
When salts and minerals are dissolved in water,
their atoms take on positive or negative charges
and are free to wander in the solution. These
charged atoms are called ions. For example,
sodium chloride, or common salt, splits into
positively charged sodium (cation) and negative-
ly changed chloride (anion) ions.
An insoluble material which can remove ions by
replacing them with an equivalent amount of a
similarly charged ion.
A unit of weight (1,000 grains) equal to l/17th
of a pound.
Kilograins (expressed as calcium carbonate) per
cubic foot of ion exchange resin.
The amount of unadsorbed ion present in the
effluent of a treatment component.
Lime refers to compounds of calcium. Hydrated
lime is calcium hydroxide. Lime which is not
hydrated is referred to as quick lime, which is
calcium oxide.
Radioactivity input into a treatment system will
equal the sum of all output streams when there
is no significant accumulation in the system.
Millions of gallons per day.
The microcurie (one millionth curie) is a unit
of quantity of radioactivity used in expressing
very low natural or environmental levels
(KT6 Ci).
A unit of concentration referring to the milli-
grams weight of a solute per liter of solution.
The term is approximately equal to the older
"part per million" term.
The picocurie per liter (one million millionth
curie) is a. measure of the concentration of
radioactivity in a liter of given water
(10"12 Ci).
145
-------
Product Water
Regeneration
Rinse
RO
Salometer Degree
Softening
Total Solids
Turbidity
Unit Cost
Zeolite Softening
Output of a desalt or reverse osmosis plant.
Restoration of an ion exchange resin to its
desired ionic form by a brine rinse.
The removal of chlorides of calcium and magnesium
and excess regenerant from an ion exchange resin.
Reverse osmosis demineralization process.
Measurement of salinity in brine solution by
specific gravity hydrometer with scale of 100
degrees at complete saturation of 26.3% NaCl.
Removal of the hardness (calcium and magnesium
ions) from water.
The number of milligrams per liter of all
dissolved and suspended solids in a given water.
Equivalent to total residue.
An expression of the optical property of a
sample which caused light to be scattered and
absorbed rather than transmitted in straight
lines through the sample. Turbidity is due to
fine visible material in suspension, which may
not be of sufficient size to be seen as individu-
al particles by the naked eye but which prevents
the passage of light through the liquid.
Generally expressed in terms of cost in cents per
thousand gallons of water. All cost comparisons
are related to the unit costs of treated water.
Common expression for ion exchange softenint.
146
-------
. APPENDIX
SECTION A
COMPLETE MINERAL ANALYSIS
147
-------
Table A-l
COMPLETE MINERAL ANALYSIS - Greenfield
Date
Source
Samp] ing Data
ANALYSIS
(Mi 1 igrams per 1 iter)
Specific Conductance
microhms @25°C
PH
Total Residue
Fi Itrable Residue
Alkalinity as CaCO P
Hardness as
Total Iron
Soluble Iron
Silica (Si 02)
Positive Ions
Potassium
Sod i urn
Calcium
Magnesium
Manganese
Negative Ions
Nitrate
Fluoride
Chloride
Sulfate
Bicarbonate
Carbonate
Trace Metals
Arsenic
Barium
Cadmium
Chromium
Copper
Lead
Zinc
Mercury Ug/l
Silver
Radioactivi ty
(picocuries/L)
Gross Alpha
Radium-226
8-8-74
Well #1
5hrs
3000
7-8
2150
2150
0
190
630
1.6
1.6
13
25
440
160
54
<0.01
-------
Table A-2
COMPLETE MINERAL ANALYSIS-ADAIR
9-16-74
Well #3
6hr 190gpm
9-17-74
Filter Inf
6hrs
9-16-74
Filter Eff
25,000 gal
9-18-74
Filter Eff
BW 2Min
2600
16
6.3
than
2700
Date
Source
Sampling Data
ANALYSIS
(Miligrams per liter)
Specific Conductance
microhms @25°C
PH
Total Residue
FiItrable Residue
Alkalinity as CaCO P
3 T
Hardness as
Total Iron
Soluble Iron
Silica (Si 02)
Positive Ions
Potassium
Sod i urn
Calcium
Magnesium
Manganese
Negative Ions
Nitrate
Fluoride
Chloride
Sulfate
Bicarbonate
Carbonate
Trace Metals
Arsenic
Barium
Cadmium
Chromium
Copper
Lead
Zinc
Mercury
SiIver
Radioactivi ty
(picocuries/L)
Gross Alpha
Radium-226
Iron results are expected to be higher
in bottle with an iron cap.
*Lab. Note—Silica could be in error due to high iron value
2700
6.8
6.9
10
7-7
2600
7.5
1921
1905
None
158
710
0.58
0.04
8.6
40
330
180
70
0.01
5-5
2.8
330
780
200
none
-------
Table A-3
COMPLETE MINERAL ANALYSIS' Stuart
Date
Source
Sampling Data
ANALYSIS
(MiJigrams per liter)
Specific Conductance
microhms @25°C
PH
Total Residue
Fi1trable Residue
Alkalinity as CaCO P
3 T
Hardness as CaCOo
Tota1 Iron
Soluble Iron
Silica (Si 02)
Positive Ions
Potassium
Sodium
Calcium
Magnesium
Manganese
Negative Ions
Nitrate
Fluoride
Chloride
Sulfate
Bicarbonate
Carbonate
Trace Metals
Arsenic
Barium
Cadmi urn
Chromium
Copper
Lead
Zinc
Mercury P9/1
Silver
Radioactivi ty
(picocuries/L)
Gross Alpha
Radium-226
10-22-74
Well #3
5hrs 300gpm
2500
10-22-74
Filter BW
@ 2min
2500
10-22-74
Dist System
Amoco Sta
2500
7.6
1770
1770
None
182
640
0.94
0.94
10
38
310
150
62
<0.01
1.5
2.6
240
780
222
None
<0.01
< 0.1
<0.01
<0.01
<0.01
<0.01
<0.01
< 1
<0.01
7.6
2178
1748
None
186
630
12C
120
56
35
310
160
62
0.23
7.6
3.1
260
790
227
None
<0.01
< 0.1
<0.01
<0.01
0.03
<0.01
0.04
1.6
<0.01
7.65
1740
1740
None
170
620
0.22
0.22
10
35
310
150
62
<0.01
5.2
2.8
250
780
207
None
<0.01
< 0.1
<0.01
<0.01
0.03
<0.01
0.01
< 1
<0.01
32
16
340
230
23
12
150
-------
Table A-4
COMPLETE MINERAL ANALYSIS- Eldon
9-11-74
Well #8
6hrs 250gpm
9-12-74
IR Filter
Eff 12hr
9-12-74
#1 Exchanger
@ 40,000
1900
1900
74
44
2000
5.6
1.3
9-11-74
IR Filter
BW 2min
1900
Date
Source
Sampling Data
ANALYSIS
(Millgrams per liter)
Specific Conductance
microhms @25°C
PH
Total Residue
Fi1trable Residue
Alkalinity as CaCO P
Hardness as CaCO^
Total Iron
Soluble Iron
Silica (Si 02)
Positive Ions
Potassium
Sodium
Calcium
Magnesium
Manganese
Negative Ions
Nitrate
Fluoride
Chloride
Sulfate
Bicarbonate
Carbonate
Trace Metals
Arsenic
Barium
Cadmium
Chromium
Copper
Lead
Zinc
Mercury yg/1
Silver
Radioactivi ty
(picocuries/L)
Gross Alpha 53
Radium-226 5°
Iron result may be higher because sample was collected in bottle with
an i ron cap. ,'
"Nitrate could not be analyzed due to extreme chloride interference.
Trace metals may be in error due to extreme chloride interference.
7.5
1228
1228
None
252
400
1-9
1.9
9.8
22
280
82
37
0.01
1.0
1.5
160
490
307
None
<0.01
< 0.1
<0.01
<0.01
0.02
<0.01
<0.01
< 1
<0.01
7-85
1218
1209
None
247
380
0.51
0.51
10
37
280
83
37
0.01
3.6
1.8
160
490
301
None
<0.01
< 0.1
<0.01
<0.01
0.01
<0.01
<0.01
< 1
<0.01
8.0
1350
1316
None
2*»1
8.0
0.11
0.11
9.2
6.0
430
2.3
0.9
0.01
6.4
1.8
160
500
294
None
<0.01
< 0.1
<0.01
<0.01
0.04
<0.01
0.04
< 1
<0.01
7.6
1703
1234
None
246
370
230
230
66
37
280
94
38
0.86
7.7
1.8
170
500
300
None
0.01
0.1
<0.01
<0.01
0.01
<0.01
0.08
< 1
<0.01
1540
1027
151
-------
Date
Source
Samp]ing Data
ANALYSIS
(Miligrams per liter)
Specific Conductance
microhms @25°C
PH
Total Residue
Fi1trable Res idue
Alkalinity as CaCO P
3 T
Hardness as CaCO?
Total Iron
Soluble Iron
Silica (Si 02)
Positive Ions
Potassium
Sodium
Calcium
Magnes i urn
Manganese
Negative Ions
Nitrate
Fluoride
Chloride
Sulfate
Bicarbonate
Carbonate.
Trace Metals
Arseni c
Bar!urn
Cadmium
C h rom i urn
Copper
Lead
Zinc
Mercury Pg/1
S i1ve r
Radioactivi ty
(picocuries/L)
Gross Alpha
Radium-226
Table A-4 (cont.)
COMPLETE MINERAL ANALYSIS' Eldon
9-13-7*
Brine Rinse
30m in
86,000
6.4
88,372
88,362
None
126
27,000
0.54
0.54
9.4
14,800
6,000
2,600
0.17
0.4
41,000
1,100
154
None
< 0.01
•1.4
< 0.01
< 0.01
0.08
< 0.1
0.05
< 1
< 0.01
4,000
3,500
Iron result may be higher because sample was collected in bottle with
an i ron cap.
'-•Nitrate could not be analyzed due to extreme chloride interference.
Trace metals may be in error due to extre-" chloride interference.
152
-------
Table A-5
COMPLETE MINERAL ANALYSIS - Estherville
Date
Source
Sampling Data
ANALYSIS
(Millgrams per liter)
Specific Conductance
microhms @25°C
PH
Total Residue
F5Itrable Residue
Alkalinity as CaCO P
3 T
Hardness as CaCO?
Total Iron
Soluble Iron
Silica (Si 02)
Positive Ions
Potassium
Sodium
Calcium
Magnesium
Manganese
Negative Ions
Nitrate
Fluoride
Chloride
Sulfate
Bicarbonate
Carbonate
Trace Metals
Arsenic
Barium
Cadmium
Chromium
Copper
Lead
Zinc
Mercury ug/1
Silver
Radioactivi ty
(picocuries/L)
Gross Alpha
Radium-226
10-8-7**
Well #8
6hr SOOgpm
1700
7.1
1350
1350
None
367
915
1.6
1.6
20
7-5
59
240
83
0.24
0.1
0.25
3
670
448
None
0.01
O.I
0.01
0.01
< 0.01
< 0.01
< 0.01
< 1
< 0.01
5.5
5.2
10-8-74 10-9-74
IR Filter #3 Exchanger
EFF 30 day Eff 502
1600
2000
10-9-74
Blended
Eff 10hr
2000
7.7
1360
1360
None
372
915
2.8
2.8
20
7-6
55
240
83
0.27
14
0.3
2
670
354
None
<0.01
< 0.1
<0.01
<0.01
<0.01
<0.01
<0.01
< 1
<0.01
7.5
1360
1360
None
386
36.0
0.08
0.08
16
3-5
420
11
4.1
< 0.01
5.7
0.7
3
630
471
None
< 0.01
< 0.1
< 0.01
< 0.01
< 0.01
<0.01
< 0.01
< 1
<0.01
7.6
1370
1370
None
398
48.0
0.10
0.10
15
3-8
420
13
3.8
0.01
7.4
0.75
9.5
630
486
None
<0.01
< 0.1
<0.01
<0.01
<0.01
<0.01
0.02
< 1
<0.02
16
8.1
3.3
0.1
1.4
0.5
153
-------
Table A-5 (cont.)
COMPLETE MINERAL ANALYSIS - Esthervi 1 le
Date
Source
Sampling Data
ANALYSIS
(MMigrams per liter)
Specific Conductance
microhms @25°C
PH
Total Residue
Filtrable Residue
Alkalinity as CaCO P
3 T
Hardness as CaCOj
Total Iron
Soluble Iron
Silica (Si 02)
Positive Ions
Potassium
Sod i urn
Calcium
Magnesium
Manganese
Negative Ions
Nitrate
Fluoride
Chloride
Sulfate
Bicarbonate
Carbonate
Trace Metals
Arsenic
Barium
Cadmium
Chromium
Copper
Lead
Zinc
Mercury
SiIver
Radioactivi ty
(picocuries/L)
Gross Alpha
Radium-226
*Due to high chloride
No metals analysis.
10-9-7^
Brine Rinse
15 min
48,000
6.9
48,900
48,900
None
546
10,800
0.34
0.34
20
140
13,000
3,100
820
0.78
0.9
26,000
1,400
666
None
128
52
interference nitrate could not be analyzed.
154
-------
Table A-6
COMPLETE MINERAL ANALYSIS - Grinnell
Date
Source
Sampling Data
ANALYSIS
(Miligrams per liter)
Specific Conductance
microhms §25°C
PH
Total Residue
FiItrable Residue
Alkalinity as CaCO P
3 T
Hardness as CaCOo
Total Iron
Soluble Iron
Silica (Si 02)
Positive Ions
Potassium
Sod i urn
Calcium
Magnesium
Manganese
Negative Ions
Nitrate
Fluoride
Chloride
Sulfate
Bicarbonate
Carbonate
Trace Metals
Arsenic
Barium
Cadmium
Chromium
Copper
Lead
Zinc
Mercury
Silver
Radioactivity
(picocuries/L)
Gross Alpha
Radium-226
8-18-74
Well #5
4hrs 460 gpm
1100
8-18-74 8-18-74
Well #6 Well #7
4 hr SOOgpm -3hr 690gpm
<0.01
14
6.2
1300
<0.01
1100
<0.01
23
7.2
5.4
4.1
8-18-74
Exchanger
#2 Inf 4 hr
1200
7.35
784
784
None
298
368
1.1
1.1
8.8
16
110
82
43
0.01
<0.1
1.2
18
320
364
None
7.3
922
922
None
334
420
0.26
0.26
8.4
19
130
98
46
0.01
<0.1
1.2
24
380
407
None
7.3
742
742
None
263
368
0.76
0.76
8.4
15
95
82
44
0.01
<0.1
1.2
16
290
321
None
7.55
822
822
None
290
384
0.41
0.41
9.0
16
120
88
44
0.01
2.2
1.2
22
340
354
None
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
ug/i
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<1 Ug/l
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
-------
Date
Source
Sampling Data
AUALYSIS
(Mil!grams per liter)
Specific Conductance
microhms @25°C
PH
Total Residue
FiItrable Residue
Alkalinity as CaCO P
Hardness as CaCO^
Total Iron
Soluble Iron
Silica (Si 02)
Positive Ions
Potassium
Sodium
Calcium
Magnesium
Manganese
Negative Ions
Nitrate
Fluoride
Chloride
Sulfate
Bicarbonate
Carbonate
Trace Metals
Arsenic
Barium
Cadmium
Chromium
Copper
Lead
Zinc
Mercury pg/1
Silver
Radioactivity
(picocuries/L)
Gross Alpha
Table A-6 (cont.)
COMPLETE MINERAL ANALYSIS' Grinnell
7-18-74
Exchanger
#2 Eff 50%
1300
1.7
0.2
7-18-74
Blended
Eff 1 hr
1300
10-31-74
Brine Rinse
30 Min
81,700
7.7
860
860
None
292
6.0
0.03
0.03
7.4
0.8
290
2.4
0.5
0.01
0.1
1.3
21
330
356
None
< 0.01
< O.'l
< 0.01
< 0.01
< 0.01
< 0.01
< 0.01
< 1
< 0.01
8.65
880
880
17.0
328
100
0.14
0.14
8.2
16
260
21
11
0.01
0.45
1.3
21
330
359
20.4
<0.01
< 0.1
<0.01
<0.01
<0.01
<0.01
<0.01
< 1
<0.01
7.0
56,400
56,400
None
264
19,800
0.25
0.25
10
440
11,000
5,120
1,700
0
*
0.8
32,000
900
322
None
2.5
1.4
470
290
Radium-22JS
*Due to nigh chloride interferences nitrate could not be analyzed
No metals analysis.
156
-------
Table A-7
COMPLETE MINERAL ANALYSIS - Hoi stein
Date
Source
Sampling Data
ANALYSIS
(Millgrams per liter)
Specific Conductance
microhms @25°C
PH
Total Residue
Filtrable Residue
Alkalinity as CaCO P
3 T
Hardness as
Total Iron
Soluble Iron
Silica (Si 02)
Positive Ions
Potassium
Sod i urn
Calcium
Magnesium
Manganese
Negative Ions
Nitrate
Fluoride
Chloride
Sulfate
Bicarbonate
Carbonate
Trace Metals
Arsenic
Barium
Cadmium
Chromium
Copper
Lead
Zinc
Mercury yg/1
Silver
Radioactivity
(picocuries/L)
Gross Alpha
Radium-226
11-24-74
Well #1
4hr 220gpm
1800
11-24-74
Aerator
Eff 5hr
1800
11-24-7**
IR Filter
Eff 1 wk
1800
11-29-74
Exchanger
Eff 25,000
2200
7. 1
1510
1510
None
288
920
1.8
1.8
9.0
1 1
110
240
69
0. 15
0.2
0.85
7
800
351
None
<0.01
< 0.1
<0.01
<0.01
<0.01
<0.01
<0.01
< 1
<0.01
7.6
1510
1510
None
290
870
1.6
1.6
9.0
11
110
240
69
0.14
1.1
0.85
7
790
354
None
<0.01
< 0.1
<0.01
< 0.01
<0.01
<0.01
<0.01
< 1
<0.01
7-35
1500
1500
None
284
880
0.09
0.09
9-0
11
110
240
69
0.01
5.2
0.85
8
790
346
None
< 0.01
< 0.1
< 0.01
< 0.01
< 0.01
< 0.01
< 0.01
< 1
< 0.01
7.45
1490
1490
None
276
15.0
0.03
0.03
11
4.7
510
4.0
1.3
0.01
3.1
0.85
10
790
337
None
< 0.01
< 0.1
< 0.01
< 0.01
< 0:01
0.02
< 1
<0.01
26
14
32
10
32
7.3
1.9
0.4
157
-------
Table A-7 (cont.)
COMPLETE MINERAL ANALYSIS - Hoi stein
Date
Source
Sampling Data
ANALYSIS
(Millgrams per liter)
Specific Conductance
microhms @25°C
pH
Total Residue
Filtrable Residue
Alkalinity as CaCO P
3 T
Hardness as CaCOj
Total Iron
Soluble Iron
Silica (Si 02)
Positive Ions
Potassium
Sod i urn
Calcium
Magnesium
Manganese
Negative Ions
Nitrate
Fluoride
Chloride
Sulfate
Bicarbonate
Carbonate
Trace Metals
Arsenic
Barium
Cadmium
Chromium
Copper
10-29-7^
Brine Rinse
10 min
185,000
6.0
166,000
166,000
None
98.0
78,000
0.78
0.78
10
650
19,000
20,000
5,000
2.7
0.85
73,000
1,200
120
None
<0.01
0.2
<0.01
<0.01
<0.01
0.04
< 1
<0.01
Lead
Zinc
Mercury yg/1
Silver
Radioactivity
(picocuries/L)
Gross Alpha 1,700
Radium-226 700
ADue to high chloride unable to make
metal results may be in error due to
interferences in analysis.
nitrate analysis. Heavy
high salt content which causes
158
-------
Table A-8
COMPLETE MINERAL ANALYSIS - Webster City
Date
Source
Sampling Data
ANALYSIS
(Miligrams per liter)
Specific Conductance
microhms @25°C
PH
Total Residue
Filtrable Residue
Alkalinity as CaCO P
3 T
Hardness as
Total Iron
Soluble Iron
Silica (Si 02)
Positive Ions
Potassium
Sodium
Calcium
Magnesi urn
Manganese
Negative Ions
Nitrate
Fluoride
Chloride
Sulfate
Bicarbonate
Carbonate
Trace Metals
Arsenic
Barium
Cadmium
Chromium
Copper
Lead
Zinc
Mercury yg/1
SiIver
Radioactivity
(picocuries/L)
Gross Alpha
Radium-226
8-13-7*1
Well #5
6hr 950gpm
1400
8-13-7*
Aerator
Eff 5hr
1400
8-13-74
Filter #4
Eff 5hr
1100
7.3
1010
1010
None
294
530
0.69
0.69
3.6
18
130
110
48
<0.01
1.7
1-3
71
380
359
None
< 0.01
< 0.1"
< 0.01
< 0.01
0.01
< 0.01
< 0.01
< 1
< 0.01
7-75
971
971
None
296
510
0.64
0.64
8.2
16
120
110
50
<0.01
1.7
1.0
65
390
361
None
<0.01
.< 0.1
<0.01
<0.01
<0.01
<0.01
<0.01
< 1
<0.01
9.3
746
746
32.0
84.0
264
0.02
0.02
8.0
15
110
39
44
<0.01
1.9
1.0
62
370
24.4
38.6
<0.01
< 0.1
<0.01
<0.01
0.01
<0.01
0.57
< 1
<0.01
14
7.1
20
6.8
3.6
0.9
159
-------
Table A-9
COMPLETE MINERAL ANALYSIS - West Des Moines
Date
Source
Sampling Data
ANALYSIS
(Millgrams per liter)
Specific Conductance
microhms @25°C
PH
Total Residue
FiItrable Residue
Alkalinity as CaCO P
3 T
Hardness as CaCO-a
Tota1 Iron
Soluble Iron
Silica (Si 02)
Positive Ions
Potassium
Sod i urn
Calcium
Magnesium
Manganese
Negative Ions
Nitrate
Fluoride
Chloride
Sulfate
Bicarbonate
Carbonate
Trace Metals
Arsenic
Barium
Cadmium
Chromium
Copper
Lead
Zinc
Mercury ug/1
SiIver
Radioactivity
(picocuries/L)
Gross Alpha
Radium-226
8-1-74 8-1-74 8-1-74
Well #1 Well #2 Clarifier
12hr 1200gpm 12hr 1200gpm Inf 12hr
1700
1700
1700
8-1-74
Clarifier
Eff 12 hr
1500
7-4
1200
1200
None
260
376
0.36
0.36
10
18
250
87
40
<0.01
<0.1
2.2
65
550
317
None
< 0.01
< 0.1
< 0.01
< 0.01
< 0.01
< 0.01
< 0.01
< 1
< 0.01
7-5
1200
1200
None
258
372
0.33
0.33
10
18
250
88
40
< 0.01
< 0.1
2.4
67
570
315
None
< 0.01
< 0.1
< 0.01
< 0.01
< 0.01
< 0.01
< 0.01
< 1
< 0.01
8.0
1180
1180
None
260
376
0.25
0.25
9.6
18
250
88
40
<0.01
0.9
2.4
65
570
317
None
<0.01
< 0.1
<0.01
<0.01
<0.01
<0.0l
<0.01
< 1
<0.01
10.4
1030
1030
56.0
80.0
188
0.03
0.03
7.8
18
260
33
27
<0.01
0.8
1.9
66
580
None
14.4
<0.01
< 0.1
<0.01
<0.01
<0.01
<0.01
<0.01
< 1
<0.01
26
9.6
24
11
29
10
7.3
2.6
160
-------
Table A-9 (cont.)
COMPLETE MINERAL ANALYSIS - West Des Molnes
Date 8-1-75
Source Filter
Sampling Data Eff 12hr
ANALYSIS
(Miligrams per liter)
Specific Conductance 1500
microhms @25°C
pH 9.5
Total Residue 1010
Filtrable Residue 1010
Alkalinity as CaCO, P 30.0
3 T 90.0
Hardness as CaCO? 192
Total Iron < 0.01
Soluble Iron < 0.01
Silica (Si 02) 7.8
Positive Ions
Potassium 18
Sodium 2AO
Calcium 31
Magnesium 27
Manganese < 0.01
Negative Ions
Nitrate °-6
Fluoride ^
Chloride 68
Sulfate 590
Bicarbonate £?.b
Carbonate 36<0
Trace Metals
Arsenic < 0.91
Barium < 0'. 1
Cadmium < 0.01
Chromium < 0.01
Copper < 0.01
Lead < 0.01
Zinc < 0.01
Mercury ug/1 < 1
Silver < 0.01
Radioactivity
(picocuries/L)
Gross Alpha 8.1
Radium-226 2-3
161
-------
APPENDIX
SECTION B
RADIUM-226 DISTRIBUTION COMPUTATION
162
-------
Table B-l
Radium-226 Distribution in Treatment Process
Greenfield, Iowa
Reverse Osmosis Desalting Plant
August 8, 1974
Ra-226 content in well water supplied
144,090 gallons including 69% finished water and 31% reject to waste
144,090 gallons x 3.785 x 14pCi/l x 10~6 = 7.62>uCi
Ra-226 accumulation in 45, 370 gallons reject water (31%)
45,370 gallons x 3.785 x 43pCi/l x 10~6 = 7.40 JuCi
% reject water 45,370 4 144,090 - 31%
Ra-226 remaining in permeator product (plant effluent)(69%)
98,720 gal. x 3.785 x 0.6pCi/l x 10~6 = 0.22juCi
% product water 98,720 7 144,090 = 69%
163
-------
Table B-2
Radium-226 Distribution in Treatment Process
Ada i r, Iowa
Greensand Iron Removal Plant
September 8,
Ra-226 content in well water supplied 2 days
212,000 gallon pumpage during period
212,000 gallons x 3.785 x 5.6 pCi/1 x-10~6= 5.3-uCi
Ra-226 content in influent to greensand filters
No reduction thru 2 hr. detention tank
212,000 gallons x 3-785 x 6.6 pCi/1 x 10~6 = 5-3-AJCi
Ra-226 content in greensand filter backwash
Three samples collected over 8 min. period
Total 3.190 gallons backwash from both filters
3,190 gallon x 3-785 x composite pCi/1 x 10~6 = 1.
Ra-226 content in effluent from greensand filters
Four samples collected over period of operation
212,000 gallons x 3-785 x 6.3 (composite) pCi/1 x 10 = 5-OjuCi
164
-------
Table B-3
Radium-226 Distribution in Treatment Process
Adafr, Iowa
Greensand Iron Removal Plant
May 13, 1975
Ra-226 content in aerated well water influent to greensand filters
8 hrs. pumping at 115 gpm rate
No reduction thru settling
55,200 gallons x 3-785 x 13 pCi/1 x 10~6 = 2.72vuCi
Ra-226 content in greensand filter backwash
Five sample composite collected over 20 min. period
150,^70 gallons filtered before backwash
Total 2,710 gallons backwash from filter
2,710 gallon x 3-785 x 200 (composite) pCi/1 x 10~6 = 2.05tuCi
Prorated to 55,200 gallon filter effluent flow
2.05-uCi x 55,200 f 150,^70 = 0.75 ,/uCi
Ra-226 content in effluent from greensand filters
Four samples collected over period of operation
55,200 gallons x 3.785 x 8 (composite) pCi/1 x 10~6 = 1.67juCi
165
-------
Table B-4
Radium-226 Distributrion in Treatment Process
Stuart, Iowa
Pressure Iron Removal Filters
October 22, 1974
Ra-226 content in well water supplied before backwash
of filter at end of two week period
1,970,000 gallons x 3.785 x 16 pCi/1 x 10~6 = 119
Ra-226 content in settling tank effluent
Collected at 5 and 20 hours after settling
1,970,000 gallons x 3.785 x 14 pCi/1 x 10"6 = 104
Ra-226 content in iron removal backwash
14min. composite of 4 samples
300 gpm @ 14 min. 4200 gal x 4 filters = 16,800 gallons
16,800 gallons x 3.785 x composite 120 pCi/1 x 10~6 = 7.6juCi
Ra-226 content in iron removal filter effluent
Collected @ 2 hrs. after backwash and just prior to backwash
1,970,000 gallons x 3.785 x 12 pCi/1 x 10~~6 = 89
166
-------
Table B-5
Radium-226 Distribution in Treatment Process
Eldon, Iowa
Iron Removal and Zeolite Softening
September 13, 1974
Iron removal filter backwashed after two week interval
Water pumped during period 1,340,000 gallons (from operation reports)
including zeolite softener backwash and regeneration
Ra-226 content in well water pumped 14 day period
1.34 mg x 3.785 x 49 pCi/1 x 10~6 = 249 yCi
249 yCi * 15 regenerations = 16.6 yCi/regeneration
Ra-226 content removed by iron filter backwash - 4 units
8 minutes at 280 gpm
280 gpm x 8 min x 3.785 x 636 (composite) pCi/1 = 5.98 yCi
Total four units 4 x 5.98 yCi =24.0 yCi
Activity per regeneration cycle 24.0 * 15 = 1.6 yCi
Ra-226 remaining in iron removal effluent
13 mg (2 week period) x 3.785 x 43 pCi/1 = 218 yCi
Activity per regeneration cycle 218 f 15 = 14.5 yCi
Ra-226 content removed by zeolite softener backwash
22 min wash @ 90 gpm per regeneration
2000 gal x 3.785 x 30 (composite) pCi/1 = 0.23 yCi
Ra- 226 content removed by zeolite softener rinse
60 gpm rinse for 40 min during spent brine discharge
60 gpm x 40 min x 3.785 x 1960 (composite) pCi/1 =17.8 yCi
167
-------
Reduced activity to 80,000 gal regeneration as compared
with 101,000 gal actual regeneration is 14.1 pCi/regeneration
Ra-226 content remaining in zeolite softener effluent
80,000 gal x 3.785 x 43 pCi/1 = 0.58
168
-------
Table B-6
Radium-226 Distribu! ion in Treatment Process
Estherville, Iowa
Iron Removal and Zeolite Softener Plant
October 8, 1974
Ra-226 content in well water supplied before backwash
of iron removal filter at end of 30 day period.
26.2 mg pumpage during period t 144,000 gal. cycle - 182 cycles
26.2 mg x 3.785 x 5.7 pCi/1 x 10~6 = 565
Ra-226 removal by iron removal filter backwash after 30 days.
Backwash water used 86,400 gal.
86,400 gal. x 3.785 x I65(composite) pCi/1 x 10~6 = 54 -uCi
Radioactivity per cycle 7 182 =0.30 ^iCi/softener cycle
Ra-226 content in zeolite softener influent during one cycle.
130,000 gal. x 3.785 x 5.1 pCi/1 x 10~6 = 2.51 -uCi/softener cycle
Ra-226 removed by zeolite softener backwash
10 minute backwash at 315 gpm = 3150 gal.
3,150 gal. x 3.785 x 94(composite) pCi/1 x 10~6 = 1.12 WCi
Ra-226 removed by zeolite softener brine rinse
247gpm (<) 20 minutes
4,940 gal. x 3.785 x 114 (composite)pCi/! x 10~6 = 2-13
Ra-226 content in zeolite softener effluent
130,000 gal. x 3.785 x 0.3 pCi/1 x 10~6 = O-lS-uCi
169
-------
Table B-7
Radium-226 Distribution in Treatment Process
Grinnell, Iowa
Aeration, Settling and Zeolize Softening Plant
July 8, 1974
Ra-226 content in well water for one softener regeneration
216,000 gal x 3,785 x 6.7 pCi/1 xlO~6 = 5.46 uCi
Ra-226 content in settling tank effluent
216,000 gal x 3,785 x 5.7 pCi/1 x 10~6 =4.66 pCi
Ra-226 removed by zeolite softener backwash
Metered 6,000 gal x 3.785 x 12(composite) pCi/1 x 10~6 =0.27 uCi
Ra-226 removed by zeolite brine rinse
4700 gal over 60 minute period
4700 gal x3.785 x 232(composite) pCi/1 x 10~6 = 4.12 uCi
170
-------
Table B-8
Radium-226 Distribution in Treatment Process
Holstein, Iowa
Pressure Iron Removal and Zeolite Softener
October 24 & 29 - 1974
Ra-226 content in well water supplied before backwash of iron
removal filter at end of weekly period
1,092,000 gal. x 3.785 x 13 pCi/1 x 10~6 = 53.7
Assume 1/14 of this flow (76,000 gal.) and radioactivity
proportional to one softening cycle of zeolite softener
Week's radioactivity 53.7 juCi f 14 = 3.83 ,uCi/cycle
Ra-226 remaining in detention tank effluent (2 hr. dention)
Collected 6 hrs. after start of well pumping
1,092,000 gal. x 3.785 x 10 pCi/1 x 10~6 ^ 14 cycles = 2.94-uCi
Ra-226 remaining in iron filter effluent
Collected at 3 days and 7 days
70,000 I gal. x 3.785 x 7.2 pCi/1 x 10~6 = 1.91 /uCi
Ra-226 removed by iron filter backwash
295 gpm at 10 min. = 2,950 gal.
2,950 gal. x 3.785 x 80(composite)pCi/l x 10~6 = 0.89 xiCi/filter
Proportioned to regeneration cycle
0.89 juCi x 4 filters 7 1/14 = 0.025 AiCi per regeneration
Ra-226 removed by zeolite softener backwash
13 minute backwash at 140gpm = 1,720 gal.
1,720 gal. x 3.785 x 7.8 pCi/1 x 10~6 = .050 ,uCi
171
-------
Holstein (continued)
Ra-226 remaining in zeolite softener effluent
5 sample composite during softening cycle
65,000 gal. x 3.785 x 0.50 (composite) pCi/1 x 10~6 = 0.123 uCi
Ra-226 removed by zeolite softener brine rinse
5 sample composite @ flows of 28 § 75 gpm during rinse
140 gal. x 3.785 x 210 pCi/1 = 0.11 uCi
140 gal. x 3.785 x 700 pCi/1 = 0.73
140 gal. x 3.785 x 1100 pCi/1 = 0.58
375 gal. x 3.785 x 800 pCi/1 = 1.14
375 gal. x 3.785 x 70 pCi/1 = .10
Ra-226 removed by brine rinse 2.30 yCi
172
-------
Table B-9
Radium-226 Distribution in Treatment Process
Webster City, Iowa
Lime Softening Plant
August 13, 1974
Ra-226 content in well water in 1.32 MGD flow
1.32 ing x 3.785 x 6.1 pCi/1 x 10~6 = 30.6^uCi/13 hrs
Ra-226 remaining in clarifier #1 effluent
660,000 gal x 3.785 x 1.9 pCi/1 x 10~6 = 4.74,uCi/13 hrs
Ra-226 remaining in clarifier #2 effluent
660,000 gal x 3.785 x 2.6 pCi/1 x 10~6 = 6.50yuCi/13 hrs
Average Ra-226 remaining in clarifier effluent
1.31 mg x 3.785 x (1.9+2.6)/2 pCi/1 x 10~6 = 11.2^uCi/13 hrs
Ra-226 removed in #2 sand filter backwash - 40 hrs operation
14,000 gal x 3.785 x 92 pCi/1 x 10~6 = 4.87>uCi (40 hrs run)
Ra-226 removed in #4 sand filter backwash - 27 hrs operation
14,000 gal x 3.785 x 91 pCi/1 x 10~6 = 4.82>uCi (27 hrs run)
Ra-226 removed by 4 filters 19.4>u/Ci x ^g ^ = 5.6>uCi/1.31 mg
Ra-226 removed by lime sludge drawoff
2040# lime x 2.3 solids x 9.6% Dryweight x 8.33 = 5,860 gal sludge
5860 gal x 3.785 x 1114 average pCi/1 x 10~6 = 24.6yuCi
Ra-226 remaining in plant effluent
1.28 mg x 3.785 x 0.9 pCi/1 x 10~6 = 4.4/uCi to system
173
-------
Table B-10
Radium-226 Distribution in Treatment Process
Webster City, Iowa
February 20, 1975
Ra-226 content in well water, in 1.20 MGD flow
1.20 mg x 3.785 x 7.8 pCi/1 x 10~6 = 35.4/uCi
Ra-226 remaining in clarifier #1 effluent
600,000 gal x 3.785 x 0.9 pCi/1 x 10~6 = 2.04/uCi
Ra-226 remaining in clarifier #2 effluent
600,000 gal x 3.785 x 0.3 pCi/1 x 10~6 = 0.68>uCi
Ra-226 remaining in clarifier effluent
1,200,000 gal x 3.785 x (0.9+0.3)/2 pCi/1 x 10~6 = 2.72>uCi
Ra-226 removed in #3 filter backwash
14,000 gal x 3.785 x 50 pCi/1 x 10~6 = 0.26/uCi
Approximately equal to radioactivity removal by 4 filters/day
Ra-226 removed by lime sludge drawoff
7140# Dryweight removed at 9.74% dryweight x 8.33 = 8,800 gal
8,800 gal x 3.785x 980 average pCi/1 x 10~6 = 32.6/u/Ci
Ra-226 remaining in plant effluent
1.20 mg x 3.785 x 0.3 pCi/1 x 10~6 = 1.36yuCi to system
174
-------
Table B-ll
RADIUM-226 DISTRIBUTION IN TREATMENT PROCESS
West Des Moines, Iowa
LIME-SODA ASH SOFTENING PLANT
August 1, 1974
Ra-226 content in well water in 2.57 MGD Flow
2.57 MG x 3.785 x 9.3 pCi/1 x 10~6 = 91 uCi
Ra-226 content remaining in clarifier effluent
2.57 MG x 3.785 x 2.6 pCi/1 x 10~6 = 24.6 uCi
Ra-226 content in clarifier #1 lime sludge drawoff
8,700 gallons of 14.5% DW sludge
8,700 gallons x 3.785 x 2,300 pCi/1 x 10~6 = 76.0 yCi
Ra-226 content in sand filter backwash
Backwash 1.2% of day's pumpage
2.57 MG 1.2% x 3.785 x 6.3 pCi/1 = 0.73 uCi
Ra-226 remaining in filter effluents
2.57 MG x 3.785 x 2.3 pCi/1 x 10~6 = 22.6 uCi
175
-------
APPENDIX
SECTION C
CAPITAL AND OPERATING COSTS
176
-------
Table C-l
Water Capital and Operating Costs
Annual Report to State Auditor
Greenffeld
1971 1972 1973
Total Revenue $59,606 $117,598 $123,909
Expenses
Plant Operation 1*,81* 1*,133 15,791
Maintenance 1> 088
Distribution Operation 4,939 3,1*2 5,*35
Maintenance 7*9
Accounting
and Collecting 1,68? 1,719 1,6*2
Administration 6,307 7,612 7,290
Debt Service 15,716 16,210 15,760
Capital Investment 15,322 23,75* 28,207
Miscellaneous 273
Total Expenses $58,785 $68,407 $74.398
Annual Pumpage MG/yr (0 6*.9 65.6 66.8
Cost c/1000 gal (2) 9U 10*$ Ulc
Remarks
(1) Percent of RO Production 20% 21* 30%
(2) Water cost C/kgal for 1970 prior to RO treatment was 83$.
177
-------
Table C-2
Water. Capital and Operating Costs
Annual Report to State Auditor
Adair
1971 1972 1973
Total Revenue $31.269 $30.374 $75,903 (0
Expenses
Plant Operation $6,180 $11,243 $8,140
Maintenance 2,506 8,415 (2)
Distribution Operation 1,775 4,785 1,900
Maintenance 2,780 3,385
Accounting
and Collecting 839 919 495
Administration 210
Debt Service 12,625 12,454 12,795
Capital Investment 2,480 2,211 84,399 (3)
Miscellaneous 552 746 782
Total Expenses $29,947 $32,358 $120,311
Annual Pumpage MG/yr 20.9 24.5 NA
Cost c/1000 gal 143<; 132e
Remarks
(1) Includes $40,000 bond sales for water main extensions.
(2) Includes repair on greensand filter.
(3) Major portion is for water main extension to serve industry
and new housing subdivision.
178
-------
Table C-3
Water Capital and Operating Costs
Annual Report to State Auditor
Stuart
Total Revenue
Expenses
Plant Operation
Maintenance
Distribution Operation
Maintenance
Accounting
and Collecting
Administration
Debt Service
Capital Investment
Miscellaneous
Total Expenses
Annual Pumpage MG/yr
Cost C/1000 gal
Remarks
1971
$28,63^
7,376
3,816
81
325
7,720
11,102
784
$31,204
48.6
64
1972
$41,212
6,455
271
930
280
40
1,336
7,750
15,029
8,852
$40,943
56.3
73
1973
$44,437
9,465
52
5,325
1,306
7,537
8,868
12,994
$45,547
57-7
79
179
-------
Table C-4
Water Capital and Operating Costs
Annual Report to State Auditor
Eldon
1971 1972 1973
Total Revenue $23.447 $22.641 $23,915
Expenses
Plant Operation $9,67** $10,286 $11,03**
Maintenance 127 623 562
Distribution Operation 256 295 483
Maintenance 2,200 6,838 3,834
Accounting
and Collecting 1,377 916 575
Administration 46 77
Debt Service 4,579 4,268 A,679
Capital Investment 2,247 615 5,259
Miscellaneous 28°
Total Expenses $20,460 $23,887 $26,783
Annual Pumpage MG/yr 34.8 36.9 29-3
Cost c/1000 gal 59 65 91
Remarks
180
-------
Table C-5
Water Capital and Operating Costs
Annual Report to State Auditor
Esthervi1le
1971 1972 1973
Total Revenue $216.402 $375.758
Expenses
Plant Operation $99,185 $118,078
Maintenance 8,598 14,724
Distribution Operation 2,534 20,082
Maintenance 7,634 12,059
Accounting
and Collecting 6,826 23,624
Administration 9,274 30,976
Debt Service 29,885 0
Capital Investment 27,590 62,567
Miscellaneous 4,807 7,336
Total Expenses $196,333 $289.446
Annual Pumpage MG/yr 408.5 436.0
Cost c/1000 gal 46 66
Remarks
181
-------
Table C-6
Water Capital and Operating Costs
Annual Report to State Auditor
Grinnel1
Total Revenue
Expenses
Plant Operation
Maintenance
Distribution Operation
Maintenance
Accounting
and Collecting
Administration
Debt Service
Capital Investment
Miscellaneous
Total Expenses
Annual Pumpage MG/yr
Cost C/1000 gal
Remarks
(1) Includes $317,050 bond sale for capital out of new #8 Jordan well,
pump and connecting main to treatment plant.
(2) Capital outlay for cost of watermain extensions.
1971
$184,634
$99,185
8,597
2,534
7,634
6,826
9,724
29,885
27,590
8,086
$200,061
NA
1972
$174,364
$93,610
2,127
3,247
10,230
7,653
9,823
29,235
22,551
7,625
$186,101
416
44
1973
$560,478 (1)
$87,776
14,902
1,347
15,386
6,506
6,164
49,118
122,859 (2)
10,249
$314,307
407
77
182
-------
Table C-7
Water Capital and Operating Costs
Annual Report to State Auditor
Holstein
1971 1972 1973
Total Revenue $34,172 $35,226 $35,549
Expenses
Plant Operation $17,134 $18,170 $20,105
Maintenance
Distribution Operation 1,588
Maintenance 1,636 58
Accounting
and Collecting 170
Administration 165
Debt Service 5,330 5,190 6,050
Capital Investment 3,299 10,330 8,821
Miscellaneous 2,458 847 1,951
Total Expenses $30,192 $36,125 $36,985
Annual Pumpage MG/yr 51-6 50.1 NA
Cost e/1000 gal 59 72
Remarks
183
-------
Table C-8
Water Capital and Operating Costs
Annual Report to State Auditor
Webster City
Total Revenue
Expenses
Plant Operation
Maintenance
Distribution Operation
Maintenance
Accounting
and Collecting
Administration
Debt Service
Capital Investment
Miscellaneous
Total Expenses
Annual Pumpage MG/yr
Cost c/1000 gal
1971
$201.302
$69,998
18,931
3,731
21,862
21,088
7,430
41,653
$55,849
5,610
$246,152
463
53
1972
$294.909
$73,147
16,775
4,228
24,004
22,166
42,648
$124,057
6,443
$313,468
486
64
1973
$257,606
$77,812
26,801
2,765
33,926
23,075
13,061
45,508
37,827
9,121
$269,896
507
53
Remarks
184
-------
Table C-9
Water Capital and Operating Costs
Annual Report to State Auditor
West Des Moines
Total Revenue
Expenses
Plant Operation
Maintenance
Distribution Operation
Maintenance
Accounting
and Collecting
Administration
Debt Service
Capital Investment
Miscellaneous
Total Expenses
Annual Pumpage MG/yr
Cost c/1000 gal
Remarks
(1) Includes sewer rental receipts.
(2) Capital outlays for plant improvements.
(3) Large capital improvement costs applied to these years.
1971
$627,381
$122,671
2,197
22,225
3,114
31,988
117,058
126,430
824,449
14,009
$1,264, 141
520
243*
1972
$900,359
$137,044
8,073
20,973
2,579
32,914
161,030
164,610
844,196 (2)
216,422
$1,587,841 $1
613
259*
1973
$986,827
$166,509
4,365
36,534
1,184
32,510
201,263 (D
164,203
224,>913
197,770
,029,251
683
15U (3
185
-------
APPENDIX
SECTION D
RADIUM-226 ANALYSIS MODIFICATIONS
186
-------
APPENDIX
SECTION D
RADIUM-226 ANALYSIS MODIFICATIONS & ACCURACY
Precision and Accuracy of Radium-226 Analysis
For each group of water samples analyzed for total radium, a reference
sample was prepared simultaneously. The average recovery of radium-226
from the reference samples was 93.5%.
The intrinsic precision (standard deviation) of this method for a single
operator is about 5%. The overall percision (St) of a particular ana-
lysis is found by combining the standard deviation of counting (Sa) with
the intrinsic precision (Sm) as follows:
St = Sm2 + Sa2
The overall precision was computed to be within approximately + 10%
above 1.0 pCi/1 and + 0.1 pCi/1 below 1.0 pCi/1.
This method (ASTM D 2460-70) covers the separation of dissolved radium
from water for the purpose of measuring its radioactivity. The lower
limit of concentration to which this method is applicable is quoted as
1 pCi/1.
Additional Radium-226 in Water Analytical Procedures
Ref: ASTM D 2460-70 Standard Method of Test for Radionuclides of Radium
in Water.
Additional descriptions of analytical procedures used follow:
Step 10.2 For many of the samples, the pink indicator did not work sat-
isfactorily. The only indication was the forming of a precipitate.
Step 10.4 When distilled water is added to the precipitate to dissolve
it, add two drops of phenolphthalein solution and add the NH^OH until
solution is alkaline.
Step 10.6 Final precipitate is transferred to a counting planchet with
small amount of distilled water (near zero count), dried with 2 ml ace-
tone and three drops of lucite solution in acetone. A 2" dia. x 0.018"
thick x V1 deep stainless stell planchet was used.
Counting Procedure:
Samples are counted for 100 minutes starting a minimum of 24 hours after
ingrowth start time. They are counted three time approximately 29 hours
apart.
187
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The sample count is corrected for ingrowth from a chart prepared using
a 50 pCi sample of Radium-226 counted for 30 days.
A counter efficiency char was prepared likewise from a 50 pCi sample
of Radium-226 aged for 30 days.
Gross Alpha Radioactivity in Water Analytical Procedures
Ref: Standard Methods for the Examination of Water and Wastewater, 13th
Ed.
Additional descriptions of analytical procedures used are as follows:
1. The sample volume was chosen so as not to exceed 4 mg/cm^ of count-
ing area.
2. All samples, except those laden heavy with sludge, were acidified
with HC1.
3. Samples with sediment were centrifuged with the supernate used
directly (for Radium-226 determination supernate was filtered). After
preparation, the samples were heated to drive out corrosive compounds.
This process introduces some radioactivity loss.
4. Sludge sediment was dried, weighed and measured amounts were dis-
solved in distilled water with HC1.
5. For solid samples.
a. Anthrafilt was crushed and leached in distilled water with
HC1.
b. The resins were crushed and leached in distilled water with
HN03 (The same process with HC1 proved less effective). The
resins did not dissolve in any solvent available in the lab-
oratory.
188
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APPENDIX
SECTION E
SALT UTILIZATION BY ION EXCHANGE
189
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Table E-l
Salt Utilization by Ion Exchange- Summary
Eldon Estherville Grinnell Holstein
Raw water hardness mg/1 375 915 385 920
Raw water sodium mg/1 270 60 120 110
Softened water sodium mg/1 375 430 290 520
Gallons per softening cycle 106,000 130,000 200,000 55,000
Pounds salt dosage per cycle 600 2,040 1,454 904
Pounds salt dosage per million gallons 5,660 15,700 7,270 16,400
Pounds salt added by regeneration 681 1,850 870 1,970
Total chloride added to water 411 1,130 782 1,860
(Ibs x 35 7 58)
Total sodium added to water 270 745 345 780
£ (Ibs x 23 f 58)
0 Sodium increase in effluent 105 370 170 410
(softened - raw)
Sodium not used in regeneration 165 375 175 370
(mg/1 increased v mg/1 dosage)
Sodium efficiency 39% 50% 50% 47%
(increase 7 dosage)
Kgr hardness removed/regeneration 2,330 7,000 4,500 2,800
(gallons x grains hardness)
Pounds hardness removed/regeneration 332 1,000 680 400
(kgr T 7,000 gr/lb)
Pounds hardness removed/I,000,000 gal 3,140 7,700 3,400 7,280
(pounds 7 gallons/regeneration)
Salt efficiency 55% 50% 47% 44%
(Ibs utilized ~ Ibs dosage)
Ratio - salt dosage ~ hardness 1.8 2.0 2.1 2.2
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Table E-2
Salt Utilization by Ion Exchange
Eldon, Iowa
Salt dosage - 600 Ibs per 106,000 gallons cycle
- 5660 Ibs per million gallons
- 680 mg/1 NaCl added by regeneration
Total Chloride added to water 680 x 35 = 410 mg/1
58
No chloride increase in effluent during softening cycle
Total sodium added to water 680 x 23 = 270 mg/1
58
Sodium increase in effluent 375 - 270 = 105 mg/1 Na
Sodium not utilized in brine regeneration = 165 mg/1 Na
Sodium efficiency 105 mg/1 increase = 39%
270 mg/1 dosage
Hardness removed 106,000 gal x 22 gains hardness = 2,330 Kgr
Pounds hardness removed 2330 Kgr = 332 Ibs per regeneration
7000 gr/lb
Pounds hardness removed 332 Ibs x 1 MG = 3140 Ibs/million gallons
106,000 gal.
Salt efficiency 3140 Ibs utilized = 55%
5660 Ibs dosage
191
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Table E-3
Salt Utilization by Ion Exchange
Holstein, Iowa
Salt dosage - 90^ Ib per 55,000 gallons cycle
- 16^00 Ib per million gallons
1970 Ib NaCl added by regeneration
Total Chloride added to water 1970 x 55 _ ,g/-0 /i
No chloride increase in effluent during softening cycle
Total sodium added to water i860 x 23 - ygg mg/]
58
Sodium increase in effluent 520 - 110 = AlO mg/1 Na
Sodium not utilized in brine regeneration = 370 mg/1 Na
Sodium efficiency 370 mg/1 increase _
780 mg/1 dosage
Hardness removed 55,000 gal x 51 grains hardness = 2,800 Kgr
Pounds hardness removed 2800 Kgr^ = 4oo lb per regenerat;on
Pounds hardness removed frOO 1 b x 1 MG = 728o lb/mm?on gallons
Salt efficiency 7280 Ib utilized = ..0
16AOO lb dosage
192
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Table E-4
Salt Utilization by Ion Exchange
Estherville, Iowa
Salt dosage - 2040 Ib per 130,000 gallons cycle
15700 Ib per million gallons
1850 Ib NaCl added by regeneration
Total Chloride added to water 1850 x 35 ,,,„ ,,
- eg • = 1130 mg/1
No chloride increase in effluent during softening cycle
Total sodium added to water 1850 x 23 _ -j\,s- ma/i
58
Sod cum increase in effluent *»30 - 60 = 370 mg/1 Na
Sodium not utilized in brine regeneration = 375 mg/1 Na
Sodium efficiency 375 mg/1 increase =
mg/1 dosage
Hardness removed 130,000 gal x 53 grains hardness = 7,000 Kgr
Pounds hardness removed 7000_Kgr__ = 1000 ]b per regeneration
Pounds hardness removed 1000 Ib x 1 MG = 7?00 lb/minion gallons
130,000 gal
Salt efficiency 7700 Ib utilized _
15400 Ib dosage
193
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Table E-5
Salt Utilization by Ion Exchange
Grinnel1, Iowa
Salt dosage - \k$k Ib per 200,000 gallons cycle
7270 Ib per million gallons
870 mg/1 NaCl added by regeneration
Total Chloride added to water 870 x 55 _ 732 mq/i
58
No chloride increase in effluent during softening cycle
Total sodium added to water 870 x 23 _•,. ,,
gg = 3*»5 mg/1
Sodium increase in effluent 290 - 120 = 170 mg/1 Na
Sodium not utilized in brine regeneration = 175 mg/1 Na
Sodium efficiency 170 mg/1 increase _ rna,
3^5 mg/1 dosage
Hardness removed 200,000 gal x 22.2 grains hardness = k,500 Kgr
Pounds hardness removed A500 Kgr = 68o ]b regeneration
7000 gr/lb
Pounds hardness removed 680 Ib x 1 MG = 3^OQ ib/million gallons
200,000
Salt efficiency 3^00 Ib util ized
7270 Ib dosage ~
194
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APPENDIX
SECTION F
RADIATION EXPOSURE RATES IN WATER TREATMENT PLANTS
195
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Appendix F
Radiation Exposure Rates in Water Treatment Plants
Measurements were made in seven of the plants studied to detect
elevated radiation exposure rates. These measurements were made to check on
possible hazards to plant personnel and to find locations in the plant
equipment and piping where radium might be concentrating.
No elevated exposure rates were detected at the reverse osmosis and
lime-soda ash softening plants. Elevated exposure rates were detected in
the ion-exchange softeners and in the anthracite filters at three sodium
cation exchange softening plants where measurements were made and at the
greensand iron removal plant at Adair.
Adair
A survey of the plant indicated elevated levels at the greensand tank.
A profile of the tank (Figure F-l) indicates that the majority of the
radioactivity is around the tank centerline. The greensand media had been
regenerated the previous day and was about half-way through a cycle. The
natural background exposure rate around the plant was about 11 yR/hr.
Estherville
Elevated exposure rates were found throughout the plant. Exposure rates
inside the main equipment room, at working level, were 3 to 13 yR/hr above
a natural background of 7 yR/hr. An exposure rate profile at the surface
of the #2 zeolite tank (Figure F-2) indicated that the greatest concentration
of radioactivity is near the bottom of the tank, near the interface of the
zeolite and the sand-gravel base. Profiles of the other three zeolite tanks
produced similar results. No change was noted in the exposure rates when
the zeolite media were regenerated, indicating that a portion of the radio-
activity permanently remains on the media.
Grinnell
Elevated exposure rates of 3 yR/hr above the natural background rate
were detected on the surfaces of the zeolite tanks. The maximum exposure
rate was detected at the zeolite-gravel interface near the bottom of the
tanks.
Holstein
Elevated exposure rates were found on the surfaces of the zeolite tanks
and the anthracite filter tank (Figure F-3). The maximum exposure rates were
detected near the bottom of the zeolite tanks and in the top half of the
filter media (the water flow is downward). The natural background exposure
rate around the plant is about 10 yR/hr.
196
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E
o
o
m
0>
X
0 10 20 30 40 50
Gross Exposure Rate, uR/hr
60 70
80
Figure F-l Exposure Rates on Surface
of Greensand Tank, Adair, Iowa
197
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20 40
Net Exposure Rate, uR/hr
60
80
Figure F-2 Exposure Rates on Surface
of Zeolite Tank, Estherville, Iowa
198
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10 _
10 20 30 40 50 60
Gross Exposure Rate, yR/hr
70 80
90
100 110
Figure F-3 Exposure Rates on Surface
of Zeolite Tank and Anthracite Filter, Holstein, Iowa
199
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This initial investigation indicates that exposure rates in the water
treatment plants were not significant to employee safety. However, further
investigation of the exposure level during cleaning of filters and changing
of anthrafilt and ion-exchange media should be carried out to determine
whether a hazard exists under these circumstances.
200
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
ORP/TAD-76-1
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
Determination of Radium Removal Efficiencies
in Iowa Water Supply Treatment Processes
5. REPORT DATE
April 1976
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
R. J. Schliekelman
8. PERFORMING ORGANIZATION REPORT NO.
ORP/TAD-76-1
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Iowa Department of Environmental Quality
Des Moines, Iowa 50316
10. PROGRAM ELEMENT NO.
2FH120
11. CONTRACT/GRANT NO.
68-03-0491
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Radiation Programs
Washington, D.C. 20460
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA-ORP
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The study included sampling and analysis of waters from nine municipal water
treatment plants in the State of Iowa to determine the efficiency of radium-226
removal in a variety of treatment processes and to provide cost data for these
processes. Supplies with a high naturally occurring radium content over 5 pCi/1
in Jordan and Dakota sandstone formation well waters were selected and included
four different treatment processes: reverse osmosis, iron removal filtration,
sodium ion exchange, and lime-soda ash softening. Analyses were performed to
determine radium, hardness, and other parameters on the well water and removals
of these parameters through the treatment process.
Radium-226 removals through the reverse osmosis, sodium ion exchange, and
lime-sode ash softening plants were in the range of 95% removal. Radium
removals in the iron removal plants ranged from 12 to 38%.
Total annual capital and operation costs and plant operation and maintenance
costs are included but were highly variable and typical cost data could not be
developed.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Water, Treatment, Removal
Radioactivity, Radium
Potable Water
Natural Radioactivity
Water Treatment
Chemical Removal
8. DISTRIBUTION STATEMENT
19. SECURITY CLASS [ThisReport)
unclassified
21. NO. OF PAGES
212
20. SECURITY CLASS (Thispage)
unclassified
22. PRICE
EPA Form 2220-1 (9-73)
2Q1
OU.S. GOVERNMENT PRINTING OFFICE: 1976-657-695/5494
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