United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-83-030 June 1983
Project Summary
Analysis of Geothermal Wastes
for Hazardous Components
E.L Hagmann, D.D. Minicucci, and CD. Wolbach
Proposed regulations governing the
disposal of hazardous wastes led to an
assessment of geothermal solid wastes
for potentially hazardous content The
final regulations, published May 19,
1980, exempt geothermal wastes from
designation as hazardous. Samples
were collected from three active ge-
othermal areas in the western United
States: The Geysers, Imperial Valley,
and northwestern Nevada Approxi-
mately 20 samples were analyzed for
corrosivity, EP toxicity (as determined
by a specific "Extract Procedure" de-
fined in the regulations), radioactivity,
and bioaccumutation potential. The
samples were further characterized by
analysis for cations, anions, moisture
content priority pollutants, and addi-
tional trace metals in the leachate. In
addition, an aqueous extraction was
conducted at ambient pH and similar
chemical analyses were performed.
None of the samples collected at The
Geysers or in northwestern Nevada
could be classified as hazardous as
defined by the RCRA regulations pub-
lished May 19, 1980 in the Federal
Register. However, several samples
from the Imperial Valley could be classi-
fied as hazardous in one or more of the
categories of pH, radioactivity, EP toxi-
city, and bioaccumulation. These haz-
ardous properties appear to be related
to the high salinity of the associated
geothermal fluids.
This study characterized samples from
a limited geographical area and results
cannot be broadly extrapolated to other
geothermal resource areas.
This Project Summary was developed
by EPA's Industrial Environmental Re-
search 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
On December 18,1978, EPA proposed
the initial set of regulations under the
Resource Conservation and Recovery Act
of 1976 (RCRA), for managing hazardous
solid wastes. The cornerstone of these
regulations was the Agency guidance on
how to determine whether a solid waste is
hazardous. Candidate criteria were intro-
duced which formed the basis for identi-
fying hazardous wastes. Of these, four
were potentially applicable to solid wastes
produced by geothermal energy develop-
ment operations: corrosivity, toxicity, radio-
activity, and bioaccumulation potential. In
anticipation of Congressional action to
exclude geothermal wastes from the RCRA
hazardous waste management regulations
while requiring that studies be undertaken
to define the nature of these wastes, EPA
initiated a research program to evaluate
geothermal solid waste against these hazar-
dous waste criteria
The objectives of this project were (1) to
sample and analyze solid wastes repre-
senting a broad spectrum of geothermal
resource areas and type of exploration and
development activities, and (2) to prelim-
inarily determine, using the RCRA analyti-
cal protocols, whether such solid wastes
meet the criteria for being hazardous.
Technical Approach
Site Selection
Sampling sites were selected on the
basis of (1) solid wastes actually being
produced, (2) representing the variety of
-------
Table 1. Geothermal Waste Sampling and Analysis Sites
Sample*
Number
Sample Description
Location
Site Owner/Operator
Imperial Valley, California
G -1 Flash tank sediment
G -3 Brine handling pond sediment
G -6 Mud pit sediment
G -7 Fluid pit brine
G -8 Reactor clarifier sludge
G -9 Mud pit sediment
G-10 Brine pit brine
G -12 Landfill sediment
G -14 Baker tank brine
G -16 Mud pit sediment
The Geysers, California
G -19-2 Centrifuge sludge
G -20-1 Cooling tower sediment
G -22-1 Centrifuge sludge
G -23-1 Cooling tower sediment
G -24-1 Drilling sump sediment
G -26-1 Sedimentation pond sediment
G -27-1 Drilling sump sediment
Northwestern Nevada
G -30 Drilling sump sediment
G-31 Drilling sump sediment
G -32 Drilling sump sediment
East Mesa, Geothermal Test Facility
East Mesa, Geothermal Test Facility
East Mesa, Sperry Well
East Mesa, Sperry Well
Niland, Geothermal Loop Experimental
Facility
Niland, Fee # 1 well
Niland, Fee # / well
Brawley, Class 11-2 landfill
Westmorland Courier # 1 well
Westmorland Courier # 1 well
Power generating unit 12
Power generating unit 9
Power generating units 5 and 6
Power generating units 7 & 8
Beigel # 1 well near unit 18
Power generating unit 12
Aminoil # 1 well, near unit 13
Steamboat Springs, Steamboat # 1 well
Humbolt House well
Desert Peak well
Department of Energy/Westec Services
Department of Energy/Westec Services
Republic Geothermal
Republic Geothermal
Department of Energy/Magma Power
Republic Geothermal
Republic Geothermal
Imperial County Dept Public Works
MAPCO, Inc.
MAPCO, Inc.
Pacific Gas & Electric Co.
Pacific Gas Et Electric Co.
Pacific Gas & Electric Co.
Pacific Gas Et Electric Co.
Union Oil of California
Union Oil of California
Aminoil, USA
Phillips Petroleum
Phillips Petroleum
Phillips Petroleum
* Samples taken were numbered consecutively from G-1 through G-33. Resource limitations prevented analysis of all samples. Only
those analyzed are listed here.
wastes being produced, (3) the waste's
potential for containing hazardous com-
ponents, and (4) the extent to which the
wastes may be indicative of commercial
operations. A priority list of sites was thus
developed and contacts were made with
site owners/operators regarding types of
wastes generated, status of waste-pro-
ducing processes, and access procedures
The resulting sites selected, for which
sampling and analyses were performed,
are shown in Table 1.
Sample Co/lection
All samples were stored in half-gallon,
wide-mouth, polyethylene bottles. Samp-
ling equipment was simple: for brines and
pond bottom sediment a 1 -liter polyethy-
lene beaker attached to the end of an 8-
foot extension rod and, for dry sediments
an ordinary metal trowel and pipe scale
was removed with a hammer and chisel.
Sample Analysis
All samples were analyzed in accordance
with the analytical scheme shown in Figure
1. The following four tests were performed
on each original sample (before extraction
or separation):
• moisture content (or total suspended
solids)
• radioactivity (radium 226)
• bulk composition (major cations and
anions)
• corrosivity (pH of slurry or brines)
Major cations and anions in the bulk
composition analyses included the following:
Anions Cations
Chloride Aluminum
Fluoride Calcium
Silica Iron
Sulfate Magnesium
Sulfide Potassium
Sodium
Phase separation and extraction were
performed. The liquid phase and the
extract (under acid pH with acetic acid and
"ambient" pH with deionized water) were
combined for further analyses of both
extracts. These analyses included bulk
composition for major cations and anions
listed above, RCRA EP toxicity, and bio-
accumulation potential.
The eight inorganic elements in the EP
toxicity test are arsenic, barium, cadmium,
chromium, lead, mercury, selenium, and
silver. Eight additional elements included
in water quality standards were also mea-
sured-antimony, beryllium, boron, copper,
lithium, nickel, strontium, and zinc.
Organic (priority pollutant) analyses and
bioaccumulation tests were performed on
both the acid and base/neutral fractions of
three samples (G12, G22-1 and G24-1)
known or suspected to have had organic
additives introduced.
Results
The results of the total sample bulk
composition analyses are shown in Table
2.
Corrosivity was determined by measur-
ing the pH of a 5-weight-percent slurry of
each solids sample or, in the case of brine
samples, by measuring the pH of the brine
directly. The values are listed in Table 3,
which also lists the Radium 226 values of
the same samples.
Table 4 lists the analyses of the eight
RCRA trace elements of the EP toxicity test
for both the acid and the ambient pH
extracts. Table 5 lists the analyses of the
additional eight water quality standards
constituents.
Table 6 presents the results of the
organic analyses of the three samples
-------
Sample
Phase
separation
40 CFR 250.13
Solid phase | Liquid phase
Phase
separation
40 CFR 250.13
0X2}
Solid phase 1 Liquid phase
Moisture
content/
TSS
n-226
st
E>
40 C
r
Bulk composition
analysis
1
Extraction
Extraction
deionized water
Corrosivity
test
40CFR
250.13fb)
Organic
analysis**
40CFR250.15
Bulk
composition
analysis
DWS species
analysis*
40CFR250.13
DWS species
analysis*
40CFR250.13
I
Bioaccumulation
potential**
40CFR250.1S
fa)f6J
Bioaccumulation
potential**
40CFR250.15
Organic
analysis**
40CFR250.15
Bulk
composition
analysis
*Plus additional water quality criteria trace elements.
**For those samples with organic additives only.
40 CFR references were those published 12/18/78. These references were, in general, replaced by final regulations dated 5/19/81.
40 CFR 250.13(b> became 40 CFR 261.22.
40 CFR 250.13(b)12)(ii) became 40 CFR 261.24, Appendix II.
40 CFR 250.15(a)(G) became part of 40 CFR 260.22.
Figure 1. Analytical scheme.
selected for these tests. The analyses
include priority pollutant screening and
tests for bioaccumulation potential.
A comparison of the analytical results
with the RCRA criteria shows that five of
the samples analyzed exceed one or more
of the criteria and thus could be defined as
hazardous wastes. The comparison is
summarized in Table 7. Note that all of the
samples which exceed the criteria came
from the Imperial Valley and that two of
them were brine samples.
Conclusions
1. This study cannot be used to generalize
about the hazardous character of ge-
othermal wastes outside the sites stud-
ied, without considerable qualification.
Data from this study support the con-
-------
Table 2. Bulk Composition of Total Sample
Imperial Valley
G-1
G-3
G-6
G-7 (brine)
G-8
G-9
G -10 (brine)
G-12
Gi ji /A*.*.***!
- 14 (brine)
G-1 6
The Geysers
G-1 9-2
G-20-1
G-22-1
GOO *
~^O~ /
G-24-1
G-26-1
G-27-1
Northwestern Nevada
G-30
G-31
G-32
% Silica
2
15
61
23
77
49
61
Trace
Not analyzed
Trace
10
i £.
41
Trace
59
33
31
32
Approx. % Approx. %
Na, K. Ca Fe, Mg. Al
Salts Oxides
70
10 10
35 10
10 10
10 15
IK 20
1 *J £.\J
60
Not analyzed Not analyzed
40
en
ou
20
70
15
m
i \j
10 10
Table 3. Corrosivity (pH) and Radium 226 Concentrations (radium on moisture-free basis.
except as noted a)
Sample No.
Imperial Valley
G-1
G-3
G-6
G-7 (brine)
G-8
G-9
G-W (brine)
G-12
G- 14 (brine)
G-16
The Geysers
G-1 9-2
G-20-1
G-22-1
G-23-1
G-24-1
G-26-1
G-27-1
Northwestern Nevada
G-30
G-37
G-32
PH
8.8
8.8
12.0
8.7
6.1
8.4
1.6
10.0
3.8
8.8
6.2
3.7
6.6
5.1
10.1
4.2
9.6
9.3
9.8
9.1
Radium 226 (pd/g)
3.0
1.5
1.0
.0s
78.
2.1
0.4"
1.1
1320"
5.9
0
0
0
0
0.5
0
0.4
1.0
1.6
3.8
elusions of other studies that each
geothermal resource must be considered
unique in its chemical and physical
character.
2. None of the samples of waste materials
collected at the commercial power plant
operations in The Geysers geothermal
steam fields and at the northern Nevada
exploration sites could be classified as
hazardous as defined by the criteria in
the Hazardous Waste regulations pub-
lished May 1 9, 1 980 in the Federal
Register.
3. Several samples, including brines, drill-
ing wastes, and settling pond solids
from geothermal exploration and de-
velopment sites in the Imperial Valley
could be classified as hazardous waste,
with characteristics exceeding the Haz-
ardous Waste criteria in one or more of
the categories of pH, radioactivity, EP
toxicity, and bioaccumulation.
4. The principal source of the hazardous
characteristics in the Imperial Valley is
the geothermal brine itself. Imperial
Valley brines generally have consider-
ably higher salinities than do geother-
mal fluids elsewhere. Hazardous waste
characteristics appear to be directly
related to salinity.
5. Since salinity is site-dependent it can
be concluded that the hazardous waste
character of geothermal solid wastes
will be site-dependent
6. Higher heavy metal concentrations were
always associated with low ambient
pH, but low pH did not guarantee high
heavy metal content.
7. High radioactivity (Radium 226) values
were generally associated with higher
metals content
The significance of the high bioac-
cumulation potential in one sample has
not been determined. The bioaccumu-
lating compounds were not identified.
a- not moisture-free basis; shown as pd/L .
-------
Table 4. RCRA Trace Elements in Acid Extracts and Ambient pH Extracts (mg/l)
Silver
Sample
Number
Imperial Valley
G-7
G-3
Gc
-o
G -7
G-8
Go
-y
Gif)
i \j
G-U
i*
G1A
- l*r
G-16
The Geysers
G1Q-9
t y ^
GO/V. J
4\J 1
G-J3-1
44 i
/?-?•?- 7
U £.*J 1
G.JA-1
^*r I
G -26- 1
G-27-1
svseriH.
AEP NEP
0.036 0.033
0.045 0.065
ND ND
0.3 1
0.23 0.23
0.063 ND
ND
0.10 NR
14
0.049 0.047
ND ND
0.087 0.068
ND ND
0. 1 10 0. 15
ND ND
0.02 0.034
ND 0.32
ooimni
AEP NEP
10.5 ND
3.8 0.60
1.4 ND
ND
5.0 5.4
1.8 ND
- 363
1.0 1.4
22
13 6.8
ND ND
ND ND
ND ND
ND ND
ND ND
ND ND
1.4 ND
\fO\tlllt\MIII
AEP NEP
ND ND
ND ND
ND ND
ND
NR NR
0.006 ND
0.07
ND ND
4
0.02 ND
ND ND
0.01 0.01
ND ND
NR NR
ND ND
0.008 0.007
ND ND
\jlllUIIIIUIII
AEP NEP
ND ND
ND ND
0.03 ND
ND
ND ND
ND ND
0.98
0.023 0.42
ND
ND ND
ND ND
0.029 0.023
ND ND
ND ND
ND ND
0.053 ND
0.07 ND
L.CI
AEP
ND
ND
ND
—
0.20
ND
—
ND
—
0.06
ND
0.14
0.02
0.07
ND
ND
ND
an
NEP
ND
ND
ND
ND
ND
ND
NR
0.20
83
ND
ND
0.18
0.05
0.05
ND
ND
ND
IVId
AEP
ND
ND
ND
—
ND
ND
—
ND
—
ND
ND
ND
ND
ND
ND
ND
ND
\,ui y
NEP
ND
ND
ND
ND
ND
ND
INT
INT
ND
ND
ND
ND
ND
ND
ND
ND
ND
tjffififii
AEP
ND
ND
ND
—
0.18
0.03
--
ND
—
0.10
ND
ND
ND
ND
ND
0.03
ND
NEP
ND
ND
ND
ND
0.22
0.02
ND
NR
5.1
0.12
ND
ND
ND
ND
ND
0.04
ND
AEP
ND
ND
ND
—
ND
ND
-
—
ND
ND
ND
ND
ND
ND
ND
ND
NEP
ND
ND
ND
ND
ND
ND
NR
ND
ND
ND
ND
ND
ND
ND
ND
ND
Northwest Nevada
G-30
G-31
G-32
0.06 0.26
ND 0. 14
ND ND
0.60 ND
0.060.50
0.50 ND
ND ND
0.006 0.005
ND ND
ND ND
ND 0.027
ND 0.039
ND
0.70
ND
ND
0.50
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.03
ND
ND
ND
ND
ND
ND
ND
ND
ND
AEP - Acid Extraction Procedure
NEP - Ambient pH (neutral) extraction procedure
ND - Not detected
NR -Not reported
- Not applicable
INT - Interference
Table 5. Additional Metals (Water Quality Standards) in Acid Extracts and Ambient pH Extracts (mg/l)
Nickel
Strontium
Sample
Number
Imperial Valley
G-7
G3
G-6
G-7
G-8
G-9
G-10
G-12
G-14
G-16
The Geysers
G-19-2
G*20-7
G-22-1
G-23-1
G-24-1
G-26-1
G-27-1
Northwest Nevada
G-30
G-37
G-32
nil til
AEP
0.18
ND
ND
—
ND
ND
..
ND
—
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
iivtiy
NEP
0.18
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.07
ND
ND
AEP
ND
ND
ND
..
ND
ND
—
ND
—
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
NEP
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AEP
ND
ND
ND
..
12.0
ND
..
ND
—
0.25
7.6
23.0
28.0
7.70
0.87
19.0
ND
0.30
ND
0.23
NEP
ND
ND
ND
ND
13.0
0.20
660
0.34
230
3.10
0.52
16.0
27.0
0.88
15.0
30.0
ND
0.57
ND
0.47
AEP
0.15
ND
ND
—
0.15
ND
-
ND
-
ND
ND
2.2
ND
60
ND
ND
ND
ND
ND
0.20
(JCI
NEP
ND
ND
ND
ND
ND
ND
7.4
0.23
ND
ND
ND
1.8
ND
33
ND
ND
ND
ND
0.10
0.10
AEP
0.22
0.17
ND
—
5.8
1.30
—
0.13
—
3.3
ND
ND
ND
ND
ND
ND
ND
0.50
0.05
0.30
NEP
0.14
0.13
ND
2.8
ND
1.10
NR
0.34
0.24
3.1
ND
ND
0.10
ND
ND
ND
ND
0.40
ND
0.20
AEP
ND
ND
ND
—
0.50
ND
-
ND
—
ND
ND
0.90
0.20
ND
0.30
0.40
ND
ND
ND
ND
NEP
ND
ND
ND
ND
ND
ND
0.30
ND
ND
ND
ND
0.70
ND
ND
0.50
0.40
ND
ND
ND
ND
AEP
ND
8.3
2.2
—
12.0
5.4
..
2.4
—
23.0
ND
ND
ND
ND
0.60
ND
3.5
1.0
3.0
2.6
NEP
ND
ND
ND
ND
15.0
1.5
1290
ND
1400
20.0
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AEP
0.70
0.11
0.15
—
6.4
1.3
-
0.25
-
7.0
0.20
6.2
0.06
7.5
0.30
9.0
0.08
0.12
0.42
0.14
NEP
ND
ND
ND
0.03
4.0
ND
NR
1.4
6000
ND
0.05
6.0
0.03
6.0
ND
14.0
ND
ND
0.28
0.05
AEP - Acid Extraction Procedure
NEP - Ambient pH (neutral) extraction procedure
ND - Not detected
NR - Not reported
- Not applicable
IT - Interference
-------
Table 6. Organic Analyses
Bioaccumulation Potential
Priority Pollutants
Sample
No.
G-12
G-12
G-22
G-22-1
G-24-1
G-24-1
Extract
Acid
Neutral
Acid
Neutral
Acid
Neutral
% of peak
area Log
0
72
0
0
0.39
1.8
Table 7. Comparison of Analytical Results
Sample
Number ,
Sample
Type
G8* Sludge
G/0* Brine
612" So/ids
G14* Brine
G16* Mud
All
Others **
Various
Waste Criteria
Constituent Analyzed
RCRA Limits:
Corrosivity
> 3 Potential
Negative
Positive
Negative
Negative
Negative
Negative
Compounds Concentration
Phenol
Phenol
4, 6- dinitrocresol
anthracene/
phenanthrene
Phenol
Benzo (kj
flouranthene
None detected
Phenol
2-nitro phenol
Phenol
4
2
8
0.4
14
3
2
640
with RCRA Criteria for Hazardous Wastes
Radioactivity
pH Radium-226
<2 or >12.5 >5 pCi/g or >50 pd/Lb
1.6
3.7 - 12
78 pd/g
1,320 pd/L
5.9 pCi/L
0 - 3.8 pd/g
OpCi/L
As Ba Cd
5.0 JOO.O 1.0
363
14 4
EP Toxicltya (mg/Lj
Cr Pb Hg
5.0 5.0 0.2
83
<0.020 <0.3 <0.005 <0.020 <0.020 <0.001
0.31 22 0.07 0.98 0.70
Bioaccumulation
Se Ag Log'p>3~
1.0 5.0 positive
peaks
Positive
5.1
<0.020 <0.020 Not analyzed
0.18 or zero
* Values presented only for exceedences of RCRA limits.
** Ranges presented for highest and lowest values (all within RCRA limits).
a Acid extracts and liquid sample filtrate.
b Radioactivity criteria proposed 12/18/78; not promulgated
E. L. Hagmann, D. D. Minicucci and C. D. Wolbach are with Acurex Corporation.
Energy and Environmental Division, 485 Clyde Avenue. Mountain View, CA
94042
Robert P. Hartley is the EPA Project Officer (see below).
The complete report, entitled "Analysis of Geothermal Wastes for Hazardous
Components," (Order No. PB83-188 680; Cost: $ 13.00, 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:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
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