United States
Environmental Protection
Agency
Water Engineering
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA/600/S2-88/039 Sept. 1988
vvEPA Project Summary
Radium Removal for a Small
Community Water Supply System
Kenneth A. Mangelson
In 1984, a radium removal treatment
plant was constructed tor the small com-
munity of Redhlll Forest, located In the
central mountains of Colorado. The
treatment plant consists of a process for
removing iron and manganese ahead of
an Ion exchange process tor the removal
of radium. The raw water comes from
deep wells and has naturally occurring
radium and iron concentrations of about
30 to 40 pCi/L and 7 to 10 mg/L, respec-
tively. Before the raw water enters the
main treatment plant, the raw water is
aerated to remove radon gas and carbon
dioxide.
The unique features of the Redhill
Forest Treatment Plant are related to the
ways In which the radium removed from
the raw water Is further treated and even-
tually disposed of as treatment plant
waste. A separate system removes only
radium from the backwash/regeneration
water of the ion exchange process, and
the radium Is permanently complexed on
a Radium Selective Complexer* (RSC)
resin made by Dow Chemical. The RSC
resin containing radium Is replaced with
virgin resin as needed and the resin
waste transported to a permanent final
disposal site in Beatty, NV.
The aeration system reduces the
radon gas by about 85% based upon the
data obtained. Typically, the radon gas
is reduced from 23,000 pCi/L to about
3,400 in the raw water after passing
through the aerator.
The water quality data on the opera-
tion of the ion exchange system In-
dicates that the radium In the inflow to
the ion exchange tanks is reduced from
about 22 to 35 pCI/L to 0.0 to 4 pCI/L in
the outflow from the treatment system.
•Mention of trade names or commercial products does
not constitute endorsement or recommendation for use.
The RSC system has been very effec-
tive in the removal of radium from the ion
exchange system wastewater by remov-
ing an average of over 99% of the radium
in the inflow to the RSC system. The
average inflow radium concentration was
about 1,180 pCi/L with the average ef-
fluent at about 9.0 pCi/L.
This report presents a detailed
description of the Redhlll Forest treat-
ment system and the results of in-depth
monitoring of the processes and other
factors relating to the overall operation
of the radium removal system. Included
are descriptions of modifications made
in the plant operation to improve the
overall system operation and of the pro-
cedures for final disposal of the RSC
resin containing radium.
This Project Summary was developed
by ERA'S Wafer Engineering Research
Laboratory, Cincinnati, OH, to announce
key findings of the research project that
is fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Introduction
A 21-month project was initiated to
monitor and evaluate the full-scale opera-
tion of the treatment plant processes
designed and constructed to remove iron,
manganes, and radium and to determine
appropriate methods for disposal of plant
wastewater and complexed radium waste.
In October 1985, the U.S. Environmental
Protection Agency in cooperation with the
Redhill Forest Property Owners Association
undertook a study of the Redhill Forest
water treatment system.
The following summarizes the processes
that make up the treatment plant and iden-
tify the areas where in-depth monitoring
was performed:
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1. Aeration for radon and carbon dioxide
gas removal.
2. Chemical clarification, including set-
tling and filtration for iron and,
manganese removal.
3. Ion exchange for radium and hard-
ness removal.
4. Chlorination and water stabilization.
5. Removal of radium from ion exchange
regeneration water by RSC resin.
6. Infiltration/evaporation (I/E) disposal
pond for plant wastewaters.
The problem of radium in groundwater,
which serves as the raw water supply for
the development, is common for many
communities in the United States. If the
development of new water sources that do
not have a radium problem is not possible
or economically feasible, then a treatment
process for radium removal needs to be
considered. This report concerns itself with
one treatment alternative and not with
locating new raw water sources that are
free of radium.
The treatment of well water for the
removal of radium is not practiced to any
great extent in the water treatment field.
However, the ion exchange process using
standard water softening type resins for
radium removal is well documented. The
Redhill Forest water treatment system in-
corporates a new process for concentrating
the radium removed by the ion exchange
process to simplify the final radium disposal
problem. The regeneration water from the
ion exchange process passes through a
bed of RSC resin to remove the high levels
of radium before the wastewater is dis-
charged to the I/E pond for final disposal.
There are no known water treatment
systems like the Redhill system. The RSC
resin has been used on a trial basis at
several locations primarily in Texas and one
site in Wyoming. In all these cases, raw
water from the wells was passed directly
through the RSC bed with radium levels up
to about 100 Ci/L.
Experimental Procedures
Raw water from two wells is pumped
through a countercurrent flow aeration
tower located at the booster pump house.
The purpose of the aeration process is to
remove dissolved gases, specifically radon
and carbon dioxide, from the raw water. The
water is pumped to the treatment plant at
a rate of about 90 to 100 gpm for further
water treatment to remove iron, manga-
nese, radium, and hardness prior to
Chlorination and discharge to the water
distribution system.
As the raw water enters the treatment
plant, alum, potassium permanganate, and
a polyelectrolyte are added to remove iron
and manganese by chemical precipitation.
The treatment unit is a prefabricated self-
contained unit that includes a mixing and
flocculation chamber, tube settlers, and
multi-media filtration. The effluent from the
iron and manganese removal process is
further treated to remove radium and hard-
ness in a ion exchange system that uses
a cation resin. The effluent from the ion
exchange system is chlorinated and zinc
hexame taphosphate added to control cor-
rosion and sequester any residual iron
before being pumped to the treated water
storage tank. The radium removed from the
water supply in the ion exchange process
is removed from the regeneration brine by
passing the brine through a separate treat-
ment process in which the radium is per-
manently complexed on the RSC material.
The wastewater from this process along
with the backwash wastewater from the iron
removal process is pumped to the final
disposal I/E pond. Figure 1 is a schematic
diagram of the processes presented above.
Ultimate Disposal of Wastewater
and Radium Removal from Water
Supply
The original concept and design ap-
proved by the Colorado State Health
Department for ultimate disposal of waste
generated at the treatment plant are as
follows:
Plant Wastewater
All wastewater from the plant operation
is discharged into an I/E pond. The main
purpose of the pond is to allow for rapid in-
filtration of plant wastewater into a geologic
formation, which dips steeply to the east
and is located beneath the geologic forma-
tion in the area of the raw water supply
wells. The deep wells obtain the raw water
from this formation to supply the
development.
Radium Waste
Most of the radium removed from the raw
water entering the treatment plant is even-
tually complexed on the RSC resin. As
needed, RSC resin is replaced and
transported to an approved hazar-
dous/radiological waste disposal facility for
final disposal.
Sampling and Analyses
The project generally consisted of in-
depth monitoring of the operation of the full-
scale Redhill Forest water treatment plant
over a 21-month period from October 1985
through June 1987. All water quality
parameter concentrations were determined
according to Standard Methods for the Ex-
amination of Water and Wastewater (15th
Edition).
Most of the water quality analysis work
was performed by Hazen Research
Laboratory, a commercial lab in Golden,
CO. Some analysis work was performed by
the EPA Laboratory in Cincinnati, OH, and
some radon gas analyses were performed
by Lowry Engineering in Maine.
In-depth monitoring included water quali-
ty sample collection and laboratory
analyses, field measurements, flow
measurement, and detailed plant operation
and was performed to evaluate the follow-
ing components of the treatment plant
operation:
1. Aeration system for radon removal.
Water samples were collected and
analyzed for radon concentration in
the raw water before and after
aeration.
2. Treatment system for iron and
manganese removal. Samples were
collected and analyzed on the raw
water inflow to the process and the ef-
fluent from the system to assess the
efficiency of operation. The water
samples were typically analyzed for
iron, manganese, gross alpha, gross
beta, and radium 226. The process
wastewater from backwash operations
was also analyzed on several occa-
sions to determine the composition of
the wastewater discharged to the I/E
pond for final disposal. Parameters of
primary interest for the wastewater in-
cluded total iron, manganese, solids,
and radium 226.
3. Ion exchange process for radium and
hardness removal. Water samples
were collected for the inflow and
outflow to the unit process. The
samples typically were analyzed for
iron, manganese, sodium, hardness,
gross alpha, gross beta, and radium
226. Water samples were collected
from the backwash, regeneration, and
quick rinse water on several
occasions.
4. Radium Selective Complexer process
for radium removal. This process was
monitored frequently to determine the
efficiency of radium removal from the
ion exchange process wastewater and
the buildup of radium in the complex-
er resin. Environmental radiation
monitoring of the area outside the
RSC tank surface was done to deter-
mine the exposure and to relate the
exposure to radium buildup on the
complexer resin.
-------
Booster Pump House
Radon Gas
Carbon Dioxide Gas
Radon-
3.400 pd/L
Concrete Sump
'Under Pump ^
House - 4.
Notes
Raw Water
Q= 10,000 gal
Iron = 4-7 mg/L
Na = 7 mg/L
TDS = 300 mg/L
/-^"Hardness = 200-300 mg/L
We/f Radium = 35-40 pd/L
N° 2 pH =6.5
V— Radon - 25.000 pd/L
1
1
1
1
np \
\
«Jffa/(
1
Chemica
(Alum., 1
nd Potassii
r»
Ac
aoly
im
Iron and Mant
and Filtrat
J
§
v
Idition
electrolyte.
Permanganate) \
janese
>cess
ion
Partii
+- Iron
Na =
TDS
Radi
Hard
, pH>
i Housea in
Backwash Wastewater \ Plant Build
Q = 350 gat
lron= 100-1 10 mg/L
Na = 700 mg/L
illy Treated Water TS = 570 mg/L
= 0.1 -1.0 mg/L Hardness = 0-10 mg/L
1 0 mg/L Radium = 60 pCi/L
= 300 mg/L
um =30 pd/L
ness = 200-300 mg/L Backwash Wa
f
ste water - 40C
''"^^^ Iron « 76 mg/L I
1. Ion exchange tanks are assumed to be back-
washed after 40,000 gal of water have been
treated.
2. Flows shown are average flows for every 10,000
gal of ra w water processed through the plant from
the wells.
3. The treatment processes include:
a. Aeration for carbon dioxide (pH adjustment) and
radon gas removal.
b. Chemical precipitation of iron and manganese
in the Neptune Microfloc flocculator/settler/
filter unit.
c. Ion exchange for radium removal and softening.
d. Radium removal process using Radium Selec-
tive Complexer (RSC). Removes radium from
the ion exchange backwash wastewater and
concentrates radium on comp/exer resin.
4. The normal treatment plant flowrate is about WO
gpm The water from the ion exchange process
for radium removal and softening is discharged
into the wastewater holding tank from which the
wastewater is pumped through the RSC at a
constant rate for radium removal
650.
Ion Exchange
Process
(Radium Removal
and Softening)
Radium Removal
'sing Radiun
Selective
Complexer
Regeneration Wastewater
Holding Tank
Na °* 44 mg/L I
Hardness *• 175 mg/L
TS « 736 mg/L
Radium = 42 pd/L
Treated Backwash
250 gal Constant Rate
Final Disposal of j
Backwash Wastewater in
Infiltration/Evaporation
Pond I
Chemical Addition
+- Chlorine and Zinc
Hexametaphosphate
Iron = 9.6 mg/L
Na = 10,300 mg/L
TS "37,600 mg/L
Hardness = 8,600 mg/L
Radium =7.0 pCi/L
To Morrison Formation - 1,000 gal
_—I Iron = 70 mg/L
To Distribution System
Iron 0.3
Na = 110 mg/L
TDS = 300 mg/L
Radium < 3 pci/L
Hardness = 5 mg/L
Hardness = 2,220
Radium = 40 pCi/L
Figure 1. Flow diagram of'water treatment plant processes.
5. I/E pond monitoring of the sand and
soils was done to determine the extent
of radium buildup due to the disposal
of plant wastewater containing small
amounts of radium.
General plant monitoring of plant flow
rates, volumes of water processed,
wastewater volumes, etc., was performed
for use along with water quality data in
determining plant process efficiencies,
plant operation and maintenance costs, etc.
Some radon gas measurements were
conducted on site using a RDA-200
Radon/Radon Daughter Detector unit
manufactured by EDA Instruments, Inc.
Also, some samples were collected and
sent to Lowry Engineering for additional
radon gas analysis.
Results and Conclusions
Figure 1 shows the flow volumes for each
part of the total system operation for an
assumed raw water flow volume of 10,000
gal into the plant. Also presented are the
average water quality data for each com-
ponent that makes up the treatment plant.
The aeration system has been proven to
effectively remove radon and carbon diox-
ide gases from the raw water supplied by
the deep wells. Carbon dioxide gas has
been typically reduced from about 125 to
25 mg/L in the aeration system. The reduc-
tion of radon gas has been about 85% from
about 23,000 pCi/L in the raw water to about
3,400 pCi/L in the effluent from the aera-
tion system. Additional measurements have
indicated that the radon gas concentration
in the treated water from the main treatment
plant is about 600 pCi/L. The iron remov-
-------
ed about 13% of the radium from the inflow
to this process. When the iron removal
system was backwashed, the radium
removed was wasted in the I/E final
disposal pond. Based upon the results of
the monitoring of the backwash water, the
average concentration of radium in the
wastewater was about 60 pCi/L.
The ion exchange system removes ra-
dium, hardness, and residual iron and
manganese through the use of a standard
cation exchange resin. The process has
been very effective in removing radium,
hardness, and residual iron, and in polish-
ing the effluent from the iron removal pro-
cess as long as the ion exchange capacity
is not exceeded. The monitoring results
generally indicate radium 226 levels of less
than 3 pCi/L and iron levels of less than the
recommended maximum level of 0.3 mg/L.
Frequent monitoring of the system opera-
tion has indicated that the radium
breakthrough occurs between 40,000 and
45,000 gal (i.e., 178 to 200 resin bed
volumes). The quality of the influent to and
effluent from the ion exchange process has
generally been as given in Table 1.
The RSC system is designed and
operated to remove radium from the ion ex-
change process wastewater and to per-
manently concentrate the radium on the
complexer resin. On July 10, 1986, new
RSC resin was placed in the complexer
tank and a detailed program of monitoring
the flow rate and the water quality of the
inflow and outflow was initiated. Table 2
presents a summary of some of the results
of the monitoring from July 10, 1986, up
through June 1987. It should be noted that
the flow rate through the column has been
about 22 gpm, which is equivalent to the
surface loading rate of about 10 gpm/ft2.
The RSC resin bed depth is 2 ft.
It can be seen in Table 2 that the RSC
resin is highly radium selective with
generally over 99% removal of radium from
the influent wastewater. Average data for
the water quality parameters included in
Table 2 are shown on the bottom of the
Table. The average inflow and outflow water
quality data indicate that iron, sodium,
hardness, and total solids are virtually un-
changed in passing through the resm
whereas over 99% of the radium in the in-
fluent is removed and concentrated on the
RSC resin. Also shown on the bottom of
Table 2 is the total quantity of radium
removed and concentrated on the resin
from July 10,1986, to June 10,1987. Based
upon the operation of the plant during this
time, the rate of radium buildup on the RSC
resin is about 347 /tCi/yr (347 X 106 pCi/yr).
Further, it has been determined that the
rate of radium removed from the raw water
and permanently complexed on the RSC
resin is about 9.6 /*Ci (9.6 X 106 pCi) per
100,000 gal of water treated at the plant.
After some period of operation, the RSC
resin containing radium will be removed
from the RSC tank and replaced with new
resin and the old resin will be disposed of
at a Nevada waste disposal site. It is an-
ticipated that the RSC resin will be replaced
when the radium on the complexer reaches
about 3,080 MCi (3,080 X 106 pCi). The 4 ft3
of RSC resin will then be placed in a 55-gal
drum, 3.35 ft3 of concrete will be added, and
the entire drum will be transported to
Nevada for final disposal. This method of
handling the radium waste will ensure that
the total radium content of the container to
be buried will not exceed 10 nCi/g (i.e.,
10,000 pCi/g).
Finally, plant operating costs have been
determined and estimated in Table 3.
The full report was submitted in fulfill-
ment of Cooperative Agreement No.
CR-812691-01-0 by the Redhill Forest
Property Owners Association under the
sponsorship of the U.S. Environmental Pro-
tection Agency.
Table 1. Summary of Quality of
Parameter
Flow rate, gpm
Iron, mg/L
Manganese, mg/L
Sodium, mg/L
Hardness, mg/L as CaCO3
Radium 226, pd/L
Water to and from Ion Exchange Process
Influent
90 to 100
0.15 to 2.7
0.4 to 1.3
7.4 to 12.5
212 to 350
22 to 35
Effluent
90 to 100
0.03 to 0.5
0.01 to 0 15
40 to 150
5 to 70
0 to 4
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Table 2. Summary of Water Quality Data for Regeneration Wastewater from Ion Exchange Regeneration Through RSC Resin' (Effluent Discharged
to I/E Pond)
Accumulated Parameters Tofa/
Volume
Treated Bed
Date gal Volumes Sample
7/10/86 0
7/30/86 2,400
8/31/86 9,460
9/29/86 14,600
10/30/86 22,600
11/26/86 27,700
1/14/87 39,550
2/21/87 49,700
3/18/87 57,700
6/10/87 71,700
Averages
0
Inflow
Outflow
77
Inflow
Outflow
305
Inflow
Outflow
471
Inflow
Outflow
729
Inflow
Outflow
894
Inflow
Outflow
1,276
Inflow
Outflow
1,603
Inflow
Outflow
1,861
Inflow
Outflow
2,313
Inflow
Outflow
Inflow
Outflow
Iron
mg/L
2.48
0.98
2.03
1.56
9.0
8.5
7.21
7.15
2.79
2.07
7.17
6.30
31.4
27.8
61.3
62.2
93.4
92.0
8.08
3.76
19.8
18.5
Manganese
mg/L
23.8
16.7
31.8
32.2
33.1
33.1
30.5
31.5
33.1
33.5
28.2
26.9
19.2
18.1
30.5
32.4
31.2
31.9
17.4
15.8
29.9
27.7
Sodium
mg/L
11,600
13,300
11,000
11,000
12,600
12,700
11,400
11,500
8,170
8,640
13,400
13,300
9,350
9,000
12,300
12,100
13,500
12,400
8,070
8,460
10,850
10,760
Hardness
mg/L
476
245
9,850
10,200
11,500
11,600
8,350
8,420
9,380
10,100
9,620
9,520
7,260
7,740
10,900
11,400
11,600
12,600
5,580
4,940
8,890
9,030
Total
Solids
mg/L
34,900
34,600
41,700
41,800
54,200
55,200
37,600
37,600
35,000
35,300
45,400
45,500
31,300
30,400
49,800
50,400
53,200
53,300
28,100
28,300
40,590
40,550
Radium
226
pCi/L
860 ±30
16±11
1280 ±40
1.6.±3.2
1400 ±40
9.4 ±3.5
920 ±30
4.1 ±2.4
860 ±50
5.3 ±2.8
1040 ±30
8.1 ±3.3
1070 ±60
8.4 ±2.3
1 780 ±80
7.2 ±7
2000 ±80
18±9
650 ±20
9.2 ±2.4
1181
9.0
%
Radium
Removal
98.1
99.9
99.3
99.6
99.4
99.1
99.2
99.6
99.1
98.6
99.2
Note: From 7/10/86 to 6/10/87 (i.e., 355 days), 71,700 gal of plant wastewater was treated In RSC tank. The following is the amount of radium removed and deposited in the resin.
Radium removed = 71,700 gal (3.785 L/gal) (1181-9.0 pCi/L)
= 318.1 X 106 pCi
= 318.1 ^Ci about 0.949 ^Ci/day
Estimate for year = 347 pCi
"Resin bed volume = 4.15 ft3 (31.0 gal)
-------
Table 3. Summary Treatment Plant Operating Costs
Cost/1,000 gal
Item of Water Treated
1. Plant Chemicals, Alum,
Permangante, Chtorine, etc. $0.137
Salt $0.475
2. Energy Costs $0.206
3. RSC Resin Disposal
(includes disposal and new resin) $0.088
Total $0.906*
'Operator cost not included.
-------
Kenneth A. Mangelson is with Rocky Mountain Consultants, Inc., Englewood,
CO, 80111.
Richard P. Lauch is the EPA Project Officer (see below).
The complete report, entitled "Radium Removal for a Small Community Water
Supply System." (Order No. PB 88-235 551/AS; Cost: $14.95, subject to
change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Water Engineering Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
United States Center for Environmental Research
Environmental Protection Information
Agency Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S2-88/039
H
CHICAGO
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