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SALTON SEA SOLAR PONDS
PILOT PROJECT
Agrarian Research
162 East Line Street Suite E
Bishop, CA 93514
Under contract to:
Goal of Salinity Management
• Stabilize (or reduce slightly) the salinity of the Salton Sea by permanently removing from the Sea water all the salt that enters the Sea annually through inflowing water
• Manage and stabilize Sea elevation through selective removal of excess water
Scientific Goals of the Pilot Pond
Project
• Establish the evaporation rate from the brine
• Determine the leakage rate from unlined ponds
• Develop a brine concentration path that will
determine the salinity at which the Salton Sea
brine begins making solid salt, and which will
define the chemical composition of the bittern
• Determine the annual growth rate of the salt
Additional Goals of the Pilot
Pond Project
• Develop cost-effective strategies for design, construction, operation, and maintenance of a salt removal facility
• Allow for storage of the salt removed in an environmentally benign fashion
• Conduct research regarding any potential environmental liabilities
• Public education
WHY DO A PILOT PROJECT?
•On-the-ground experience
•Specific data for design
•Biological monitoring
•Public education and
stakeholder buy-in
Pilot Project demonstrated
feasibility in field…
Pilot project at Niland, CA
Solid salt beds forming
in crystallizers
…developed data with laboratory
experiments,Accelerated
evaporation of
brine in the
laboratory
resulted in
reliable data on
brine chemistry
and salt
precipitation
Evaporation
data were
collected on site,
as well as
collection and
analysis of solid
salt samples
from the ponds
GOAL Stabilize (or reduce slightly) the salinity of the Salton Sea by
permanently removing from the Sea water all the salt that
enters the Sea annually through inflowing water
Removal of salt from the Sea is accomplished by pumping Sea brine into a series of evaporation ponds that concentrate the brine to the point where solid salts precipitate
Concentrator
Pond 1Concentrator
Pond 2Concentrator
Pond 3
Solid salt
ponds
Water volume
Concentration
Scientific data are needed to
develop an optimum design for
solar ponds
• Evaporation rates
• Leakage rates
• Characteristics of feed brine
• Brine concentration path
Evaporation rates
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
12.0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
FW
0.135
0.980
4.000
6.250
Normal year evaporation (inches) at various
concentrations (expressed as percent magnesium)
Leakage rate
Leakage rate from infiltrometer
Leakage Inches/day
Avg 0.032
Max 0.042
Min 0.022
Change in Depth in Inch/Month (Feb to November )
piezometers
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
Pond 1 Pond 2 Pond 3 Pond 4 Pond 5 Pond 6 Pond 8 Pond 9 Pond 10
5 foot
10foot
Feed brine composition
Feed Brine (in weight percent)
SG Be Ca Mg SO4 Cl K Na
1.035 4.9 0.09 0.14 1.03 1.79 0.06 1.24
Brine concentration path
0
10
20
30
40
50
60
70
80
90
1001.1
25
1.1
30
1.2
53
1.2
69
1.2
98
1.2
51
1.2
78
1.2
76
1.2
85
1.2
99
1.3
10
1.3
11
1.2
90
1.2
91
1.2
85
1.2
93
1.3
18
1.2
97
1.3
23
1.3
26
1.3
19
1.3
32
1.3
40
Perc
en
t
EntrainNaClCarnaliteEpsomSaltCake
Entrain Brine
NaCl NaCl
Carnalite KCl*MgCl2*6H20
Epsom MgSO4*7H20
SaltCake Na2SO4
Growth Rate
of SaltTotal salt
deposition in
crystallizers is
about 1.5 feet
of mixed
(dominated by
NaCl) salt per
year
Develop cost-effective strategies for design,
construction, operation, and maintenance of
a salt removal facility
From the scientific
data, Agrarian
developed a model
that generates a
pond design
specific to the
brine, climate, and
soils. This design
is for a module
that would remove
1 million tons of
salt from the Sea
Agrarian’s model was developed
from equations that are
standardized in the salt industry,
and which we validated with
literature and calibrated in the
field. The model is non-
proprietary, and is available for
review by any interested parties.
Design parameters include differences in
seasonal performanceYield: Cubic Feet Brine per Acre
-
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
45,000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
CF In
To Crystal
To bittern
Salt Production in Crystalizers and MgSO4 Pond expressed
as TDS Tons per Acre of Concentrator
-
10.0
20.0
30.0
40.0
50.0
60.0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
-
10.0
20.0
30.0
40.0
50.0
60.0To Crystalizer
Discharge
Salt Formation
Bittern Salts
Pond systems with optimum yield can be designed
using the data generated from the pilot pond project.
Such ponds can effectively remove salt from the
Salton Sea. In-sea dikes increase cost, but can
minimize extra evaporative surface.
In-sea construction was utilized at the
Great Salt Lake production facility
Allow for storage of the salt removed in
an environmentally benign fashion
Solid salts can be
stored as landfill,
making shallow,
low pyramids
capped with soil.
This strategy is
similar to that used
for mine tailings.
Original salt bed First lift Second lift
Solid salt characteristics may make it
possible to construct dikes on top of
solid salt, resulting in cost savings
Biological monitoring is being
conducted in the ponds by Tetra-Tech
• What contaminants are present?
• What organisms are exposed to the
contaminants?
• How does the exposure occur (food, water,
and sediment intake)?
Contaminants
• Metals: elevated ones are boron, copper,
nickel, selenium, and zinc
• Pesticides: analyzed ones are 20
organochloride compounds
• PCB’s: analyzed ones are 8 aroclors
Risk Characterization
Food
intake
Water
intake
Sediment
intake
Total
intake
Toxicity
value
Risk+ + = =
Potential risks will be assessed by TetraTech with
standard formulas
Public education and stakeholder buy-in
Visits to the ponds by members of the
public and the press occur at least 2-3
times per month, and serve to educate the
public about on-going projects relating to
active initiatives for Salton Sea recovery
Value for Public Relations and
Research
• Frequent visits to the ponds indicate
continued public interest in activities being
conducted by the Authority for Salton Sea
recovery
• Biological monitoring can be on-going,
increasing confidence in the results
CONCLUSIONS
• Salt can effectively be removed from the
Salton Sea using solar evaporation ponds
• The data inform a model that predicts with
confidence the optimum design for a large
scale project
• There are no obvious environmental
liabilities associated with evaporation ponds