Solar Evaporator Solar Evaporator for Integrated onfor Integrated on--Farm Drainage Management (IFDM) Farm Drainage Management (IFDM)

System at Red Rock Ranch, System at Red Rock Ranch, San Joaquin Valley, CaliforniaSan Joaquin Valley, California

Jose I. Faria P.E., Jose I. Faria P.E., Special Investigations Branch, ChiefSpecial Investigations Branch, Chief

Department of Water Resources (DWR), San Joaquin DistrictDepartment of Water Resources (DWR), San Joaquin District

Principal Investigator: Alexander Begaliev Ph. D, Principal Investigator: Alexander Begaliev Ph. D, Project Collaborators:Project Collaborators:

Kathleen Buchnoff P.E. DWR, Vashek Cervinka Ph. D, Westside ResoKathleen Buchnoff P.E. DWR, Vashek Cervinka Ph. D, Westside Resources Conservation Districturces Conservation DistrictCollaborators: Mike Delamore, U.S. Bureau of Reclamation, John DCollaborators: Mike Delamore, U.S. Bureau of Reclamation, John Diener, Jose Lopez, Red Rock Ranch. iener, Jose Lopez, Red Rock Ranch.

ObjectivesObjectives

•• To develop and demonstrate the use of solar To develop and demonstrate the use of solar evaporators as an economic, simple, and evaporators as an economic, simple, and environmentally safe method to evaporate environmentally safe method to evaporate concentrated subsurface drainage water and store its concentrated subsurface drainage water and store its salts as terminal point of an IFDM system.salts as terminal point of an IFDM system.

•• Evaluate possible recovery of drainage salts for Evaluate possible recovery of drainage salts for beneficial use.beneficial use.

IFDM System at Red Rock Ranch

• Consists of 640 acres.• Contains four salinity zones, each with a subsurface drainage system to collect agricultural

drainage water from irrigated fields.• The IFDM system manages irrigation water on salt-sensitive high value crops (tomatoes,

wheat) and reuses drainage water to irrigate salt-tolerant crops (alfalfa, cotton, tall wheat grass), salt-tolerant trees, and halophyte (saltgrass, iodine bush) plants.

• Each sequential reuse reduces the volume of drainage water and increases the salt concentration.

• Drainage water (DW) too saline for irrigation is applied to the solar evaporator (SE).• Manage salts and drainage water on-farm.• Collect the salts for potential commercial and/or industrial reuse.

Methodology of Solar Evaporator ResearchMethodology of Solar Evaporator Research

--Evaluate surface configuration to enhance evaporation, prevent Evaluate surface configuration to enhance evaporation, prevent standing water and therefore access to wildlife; standing water and therefore access to wildlife;

--Evaluate gravel materials for solar evaporator surface for solarEvaluate gravel materials for solar evaporator surface for solarheat absorption and wildlife protection;heat absorption and wildlife protection;

--Evaluate and select water spray devices (spray patterns, angles,Evaluate and select water spray devices (spray patterns, angles,and pressures);and pressures);

--Estimate weather parameters for seasonal and optimal operation Estimate weather parameters for seasonal and optimal operation a solar evaporator; a solar evaporator;

--Measure and evaluate methods to control salt drift;Measure and evaluate methods to control salt drift;--Explore separation of usable salts;Explore separation of usable salts;--Determine preliminary costs and O&M procedures;Determine preliminary costs and O&M procedures;

Solar Evaporator Pilot ProjectSolar Evaporator Pilot Project

Evaluation of configuration, volume, slope and cover materialsEvaluation of configuration, volume, slope and cover materials

Reservoir with perforated PVC pipe and gravel cover

Nozzles

Pilot Solar Evaporator RRR

Slope 2%

Water discharge meter

Drainage water from sump

100 ft

100 ft

Coarse Gravel

Area 3A

Coarse Gravel

Area 3B

Mixed Gravel

Area 2A

Mixed Gravel

Area 2B

Exposed liner (no aggregate)

Area 1A

Exposed liner (no aggregate)

Area 1B

Pumps

Fence

Types of Gravel Evaluated

COARSE

MEDIUM

SMALL

Solar Evaporator Test: Evaporative Surfaces

Area covered by coarse gravelArea covered by mixed gravel

Exposed liner area

Nozzle stand

Return flow culvert

Spray Devices Tests at the Center for Irrigation Technology Spray Devices Tests at the Center for Irrigation Technology Testing Facility at California State University, FresnoTesting Facility at California State University, Fresno

Test Nozzles

BETE TF 24- 170

BETE TF 16-170

BETE TF 12-170 BETE TF 12-180

2.5 3 3.5 4 4.5 5Height of the nozzle position, ft

10

12

14

16

18

20

Wat

er m

ist r

adiu

s, ft

17

13

10

19

15

11

18

14

11

LegendWater pressure=10 psi/water discharge=11.03 gal/minWater pressure=20 psi/ Water discharge=16.9 gal/minWater pressure=30 psi/Water discharge=20.8 gal/min

Nozzles BETE TF-24-180 and TF-12-180 (water mist radius are measured for different nozzle risers, water flow discharges, and pressures)

2.5 3 3.5 4 4.5 5Nozzle riser height, ft

5.4

6

6.6

5.7

6.3

Wat

er m

ist

radi

us, f

t

666

666

666

Water pressure= 10 psi Water discharge=3.1 gpmWater pressure=20 psi Water discharge=4.3 gpmWater pressure=30 psi Water discharge=5.5 gpm

TF-12-180TF-24-180

Spray Nozzle Tests

Vertically oriented nozzle position with different riser heightswere tested in 2003 (riser=1.5 ft) note windbreak fence

Horizontally oriented nozzle position with different riser heights were tested in 2004 (riser=1.5 ft)

Nozzle positions with different angles and with varying riser heights were tested in 2003 (riser=1.0 ft)

Measuring Weather ParametersMeasuring Weather Parameters

CIMIS Station Components:Total solar radiation (pyranometer) Soil temperature (thermistor) Air temperature/relative humidity (HMP35) Wind direction (wind vane) Wind speed (anemometer) Precipitation (tipping-bucket rain gauge)

Evaporation by Pan (Five Point Station) and Evapotranspiration by CIMIS at RRR

0 0.5 1 1.5 2 2.50.25 0.75 1.25 1.75 2.25

Evaporation, inch/day

0

0.4

0.8

1.2

1.6

2

0.2

0.6

1

1.4

1.8

Evap

otra

nspi

ratio

n, in

ch/d

ay

Eto and EoETo=0.8Eo-0.02

Linear Equation ETo= 0.8Eo- 0.02 or Eo=1.25ETo-0.025

Number of data points used = 56

Average Eo= 1.01205

Average ETo= 0.785893

Residual sum of squares = 0.308747

Regression sum of squares = 10.1932

Coef of determination, R-squared = 0.970601

Residual mean square, sigma-hat-sq'd = 0.00571754

Eo=1.25ETo-0.025

Daily Evaporation by CIMIS at RRR, 2004

0 100 200 300 400Days of 2004

0

0.1

0.2

0.3

0.4

0.5

Evap

orat

ion,

inch

/day

Graph 1Evaporation, inch/day 2Y=-0.084+0.0048X-0.0000139X

•• Measuring Enhanced Solar EvaporationMeasuring Enhanced Solar EvaporationEstimated Daily Average Solar Radiation at Red Rock Ranch

BTU/(hr)(sq.ft.)

020406080

100120

1-Jan15-Jan

1-Feb15-Feb

1-Mar

15-Mar

1-Apr

15-Apr

1-May

15-May1-Jun

15-Jun1-Jul

15-Jul1-Aug

15-Aug

1-Sep

15-Sep

1-Oct

15-Oct

1-Nov

15-Nov1-Dec

15-Dec

Energy Demand for EvaporationEnergy Demand for Evaporation

•• Heat of Vaporization: Heat of Vaporization: 1,045.55 BTU/lb H1,045.55 BTU/lb H22OO

•• QQnetnet = Q= Qsolarsolar + Q+ Qairair + Q+ Qgrgr

•• Solar RadiationSolar Radiation•• Convective Heat Transfer from AirConvective Heat Transfer from Air•• Convective Heat Transfer from GravelConvective Heat Transfer from Gravel

Solar EvaporationSolar EvaporationExample Example –– mid Junemid June

•• SE area is 100 x 100 ftSE area is 100 x 100 ft•• Solar heat input = 27.12 million BTU/day Solar heat input = 27.12 million BTU/day •• Convective heat input from gravel = 6.7 million Convective heat input from gravel = 6.7 million

BTU/dayBTU/day•• Convective heat input from air = 9.26 million BTU/day Convective heat input from air = 9.26 million BTU/day •• Total heat input = 43.08 million BTU/dayTotal heat input = 43.08 million BTU/day•• Evaporate 41,200 lbs/day of waterEvaporate 41,200 lbs/day of water

= 4,935 gallons/day = 3.43 gallons/minute= 4,935 gallons/day = 3.43 gallons/minute= 14.9 gallons/minute acre= 14.9 gallons/minute acre

Pilot Experiment ResultsPilot Experiment Results

Nozzle riser= 1.5 ft

Nozzle riser= 1.0 ft

RRR - SOLAR EVAPORATOROPERATIONAL DATA

DATE/parameters DATE DATE DATE DATE DATE DATE6/9/2003 6/10/2003 6/11/2003 6/12/2003 6/13/2003 6/14/2003

Time,start 10.50 am 9.20 am 7.55 am Tomato 10.20 am 6.43 amTime,finish 11.10 am 9.40 am 8.20 pm Tank 10.30 am 7.08 amTime duration,min 20 min 20 min 25 min 10 min 25 minInput reading,start 67400 69600 72000 74800 75900Input reading,finish 69500 72100 74800 75900 78700Input gallons 2100 2500 2800 3160 1100 2800EC 13.83 14.5 17.3 61.5 17.63 16.21Tem, C 22.1 19.1 21.8 20.7 22.8 20.2PPT,garm/L 8.5 8.4 10.1 41.1 10.4 9.6

SE runningTime,start 11.15 am 9.40 am 8.30 am 8.30 am 10.40 am 7.20 amTime,finish 4.15 pm 5.40 pm 5.30 pm 7.30 pm 1.40 pm 4.20 pmTime duration,min 5 hour 8 hour 9 hour 11 hour 3 hour 9 hourOutput reading, start 650100 672400 701460 736800 781100 790100Output reading,finish 672000 701000 736300 780500 789700 822600Volume of running,gallons 21900 28600 34840 43700 8600 32500EC 49.51 46.54 39.15 92.8 69.3 60.5Tem, C 19.7 16.7 25.2 19.2 24.6 20.6PPT, gram/L 32.4 30.3 25.3 66.7 47.4 40.8Pressure,psi 58 58 58 58 58Evaporation rate,gallons/day 2100 2300 2560 700

TOMATO TANK, Time 10.40 am 9.06 am 7.20 am 6.30 am 9.46 am 6.50 amMoved volume,gallons 400 400 460 500 600 300EC 47.38 48.84 46.77 41.05 92.8 60.5Tem,C 23.7 19.8 16.6 20.1 19.2 20.5PPT, gram/L 30.8 31.8 30.5 26.3 66.7 40.7 TOMATO TANK, Time NORTH, SOUT WESTDATE 6/9/03 EC 68.4 67.9 66.7 TEM 23.4 23.5 23.4 PPT 46.7 46.7 45.6

JUNE, 2003

0.15 0.2 0.25 0.3 0.35 0.4 0.45Evaporation by pan (Eo=1.25ETo-0.025), inches/day

1

2

3

4

5

6

Sol

ar E

vapo

rato

r-Sal

t Con

cent

rato

r (Eo

-SE-

SC),

inch

es/d

ay

ln(Y)=2.12*X+0.74riser 2.5 ftln(Y)=2.7*X+0.26riser 2.0 ftln(Y)=3.128X-0.03riser 1.5 ftln(Y)=3.22*X-0.10riser 1.0 ftln(Y)=3.218X-0.22riser 0.50 ftln(Y)=3.22*X-0.31riser 0.25 ft

Relationship between actual pan evaporation (Eo pan) and enhanced evaporation

at the pilot solar evaporator RRR, March-October 2003.

0.16 0.2 0.24 0.28 0.32 0.36Evaporation (Eo) pan, Five Points, (ETo=1.25Eo-0.025), inch/day

1

1.5

2

2.5

3

3.5

Sol

ar E

vapo

rato

r-Sal

t Con

cent

rato

r (SE

-SC

) Eo,

inch

/day

riser 2.00 ln(Y)=2.66*X+0.234riser 1.50 ft ln(Y)=3.38*X-0.228riser 0.50 ft ln(X)=3.9*X-0.518riser 0.25 ft ln(Y)=4.02*X-0.581

Relationship between actual evaporation (Eo pan) and enhanced evaporation

at the pilot solar evaporation RRR, March-October 2004.

Salt Drift Evaluation:Salt Drift Evaluation:DWRDWRCSUCSU--FresnoFresno

Salt Drift Barrier Selected

Smaller droplets drift longer distances

Evaporator Salt Drift Evaporator Salt Drift DWR EvaluationDWR Evaluation

Glass plates were use to measure salt drifting outside the SE

Evaluation by DWR

DWR Evaluation Results

00.050.10.150.20.250.30.350.40.450.50.55

Pilot Solar Evapor a tor Module (30.5x30.5 m)

Salt-dirt deposition kg/square meter since 07/29/03 until 08/26/03

Salt-dirt deposition 13.0 kg/day or0.54 kg/hour (07/29/03-08/26/03)

-10 0 10 20 30 40 50

Dist ance, meter

-10 0 10 20 30 40 50

Dist ance, meter

0

10

20

30

40

50

0

0.1

0.2

0.3

0.4

0.5

0.6Pilot Solar EvaporatorModule (30.5x30.5 m)

Salt-dirt deposition kg/squar e meter since 07/29/03 until 08/26/03

2 D salt-dirt deposition contour map

3 D salt-dir t deposition surface map

Salt Drift EvaluationSalt Drift EvaluationCSUCSU--Fresno EvaluationFresno Evaluation

Evaluation by Professor Charles Evaluation by Professor Charles KrauterKrauter

0

10

20

30

40

50

60

70

Salt Deposition, mg/m2/hour

South

North

North

South

Solar Evaporator(30x30 meters or100x100 feet)

Solar Evaporator(30x30 meters or100x100 feet)

Total salt deposition 5.9 kg/day (09/20/2004)

Nozzles raised at 0.5 ft

0

20

40

60

80

100

120

140

160

180

Solar Evaporator(30x30 meters or100x100 feet)

Salt Deposition, mg/m2/hour

Nor th

South

North

South

Solar Evaporator(30x30 meters or100x100 feet)

Total salt deposition 10.4 kg/day (08/02/2004)

Nozzles raised at 1.5 ft

051015202530354045505560

Salt Deposition,mg/m2/hour

Solar Evapo rat or(30x30 m eters or100 x100 f eet)

Solar Evaporator(30 x30 me ters or100x10 0 fee t)

South

South

North

North

Total salt deposition 22.4 kg/day (09/07/2004) test 2

Nozzles raised at 2.0 ft

Pilot Solar Evaporator Salt Drift Results

0 0.5 1 1.5 2 2.50.25 0.75 1.25 1.75 2.25

Nozzle riser height, ft

0

0.4

0.8

1.2

1.6

2

0.2

0.6

1

1.4

1.8

Salt

Dep

ositi

on, k

g/ho

ur

Experimental data(Fresno State University, Dr. Krauter)

Experimental Data(Department of Water Resources) 2 Y=9.14-20.05*X+13.77*X

Salt Drift Evaluation ConclusionsSalt Drift Evaluation Conclusions

•• DWR and CSUF evaluations agree on measured drifted rates for 1.5DWR and CSUF evaluations agree on measured drifted rates for 1.5 nozzle nozzle height (0.5 height (0.5 vsvs 0.4 Kg/hr) but disagree on deposition distance 50 0.4 Kg/hr) but disagree on deposition distance 50 vsvs 200 200 meters. meters.

•• Approximate emission rates vary from 0.2 to 1.85 lb/hr dependinApproximate emission rates vary from 0.2 to 1.85 lb/hr depending on g on nozzle elevation (0.6% to 5.3% of total SE input)nozzle elevation (0.6% to 5.3% of total SE input)

•• The 6 ft fence decreases the total emissions by interfering withThe 6 ft fence decreases the total emissions by interfering with the wind the wind pattern at the nozzle level and by intercepting 99.4 to 94.7% ofpattern at the nozzle level and by intercepting 99.4 to 94.7% of the total the total emissions before they leave the SE perimeter. emissions before they leave the SE perimeter.

•• A established salt tolerant tree barrier (30 ft or higher) placeA established salt tolerant tree barrier (30 ft or higher) placed within 100 d within 100 yards of SE will contain nearly 99.9 % of salt that drifts outsiyards of SE will contain nearly 99.9 % of salt that drifts outside the SE. It de the SE. It will allow placement of nozzles at a higher elevation, thereforewill allow placement of nozzles at a higher elevation, therefore increasing increasing evaporation rates.evaporation rates.

Salt Accumulation and SeparationSalt Accumulation and Separation

Salt mixture on the solar evaporator surface

Extractable TDS ConstituentsExtractable TDS ConstituentsAverage % by Dry Weight:Average % by Dry Weight:

•• Sodium Sulfate Sodium Sulfate 37%37%•• Sodium Chloride Sodium Chloride 33%33%•• Calcium Sulfate Calcium Sulfate 16%16%•• Magnesium Chloride Magnesium Chloride 7%7%•• Sodium Nitrate Sodium Nitrate 3% 3% •• Calcium Carbonate Calcium Carbonate 2% 2% •• Boron Boron 1%1%•• Potassium Chloride Potassium Chloride 0.8% 0.8% •• Selenium Selenium 0.01%0.01%•• Other Other 0.19%0.19%

Sequence for Increasing Salt ConcentrationSequence for Increasing Salt Concentration

Sump “D” Water

Tomato tub # 2

Tomato tub # 1

Tomato tub # 3

Tomato tub # 4

Tomato tub tanks 3,000 gallons

Step 1- tomato tub # 1- salt concentrations 27-48 ppt

Step 2- tomato tub #2- salt concentrations 41-107 ppt

Step 3- tomato tub #3- salt concentrations 61-220 ppt

Step 4- tomato tub #4- salt concentrations 77-415 ppt

To Salt Crystallization (Solar Still or Solar Evaporator)

Increasing Salt Concentration Increasing Salt Concentration

Salt accumulated at a green house at RRR

Sodium sulfate is the dominating salt in the mixture

Approximate Value of Dissolved Salt ComponentsApproximate Value of Dissolved Salt ComponentsRRR Sump RRR Sump ““DD”” Drainage Water (10 af)Drainage Water (10 af)TDS: 10,000 mg/L with 1 mg/L SeTDS: 10,000 mg/L with 1 mg/L Se

<1%<1%$20$20$7.5/ton$7.5/ton2.8 tons/yr2.8 tons/yrCalcium BicarbonateCalcium Bicarbonate

12%12%$1690$1690$300/ton$300/ton5.6 tons/yr5.6 tons/yrSodium NitrateSodium Nitrate

16%16%$2,338$2,338$255/ton$255/ton9.2 tons/yr9.2 tons/yrMagnesium ChlorideMagnesium Chloride

8%8%$1,152$1,152$25/ton$25/ton46.1 tons/yr46.1 tons/yrSodium ChlorideSodium Chloride

$14,438$14,438$1,149$1,149

$6,898$6,898

$580$580

$610$610

MarketMarketValueValue

100%100%TotalTotal8%8%$52/lb$52/lb22 lbs/yr22 lbs/yrSeleniumSelenium

49%49%$134/ton$134/ton51.5 tons/yr51.5 tons/yrSodium SulfateSodium Sulfate

4%4%$30/ton$30/ton19.3 tons/yr19.3 tons/yrGypsum (Gypsum (calcinatedcalcinated))

4%4%$425/ton$425/ton1.4 tons/yr1.4 tons/yrBoronBoron

%%ValueValueUnit ValueUnit ValueQuantityQuantity

Source USGS Mineral Commodity Statistics (Prices are fob at mineSource USGS Mineral Commodity Statistics (Prices are fob at mine 2006)2006)

Solar Evaporator Estimated CostsSolar Evaporator Estimated Costs

Pilot Solar Evaporator Estimated Costs (1 Acre)

Gravel delivered and placed $7,500Tile Drain System and Sump $5,000Grading and Excavation $4,000Pumps $5,000Spray System inc. tips $2,000Corrugated Drain Pipes $2,500Drift Fence $6,250Land (SJV Westside) $5,000Engineering fees and permits (20%) $9,313

Total Capital Costs $46,563

Capital Costs 20 yr at 7% $4,395 yearPumping Costs $6,983 yearO&M $5,400 year

Total Combined Costs $16,778 year

Brine Water Evaporated 16.50 af per ac/yrTotal Unit Cost $1,017 per af

Conclusions

With fan sprinklers at 1.5 ft, the SE achieved 3.3 times the rate of pan evaporation.

A minimum of 16.5 acre-feet per acre per year of subsurface drainage water can be evaporated at the pilot SE.

Salt drift can be minimized with a screened 6-ft fence resulting in drift rates up to 1lb per hour of operation. This represents about 1% of the total salt volume.

At higher sprinkler elevations the evaporation rates can be increased substantially, but a taller barrier will be needed to control salt drift.

Pilot demonstration project results indicate that is feasible to design, construct, and operate a solar evaporator for IFDM.

It could be used to manage concentrate from desalination processes and effluent from industrial processes

Salts can be stored and separated in different components (need large salt volume to attract commercial operations)