Nanofiltration of a High Salinity Groundwater on the Hopi Reservation

8/13/2019 Nanofiltration of a High Salinity Groundwater on the Hopi Reservation

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NANOFlLTRATlON OF A HIGH SALINITY

GROUNDWATER ON THE

HOPI RESERVATION

WilbertOdemNorthern Arizona University

Flagstaff, AZ

Contract No. 14253-CR-81.19540

Water Treatment Technology Program Report No. 3

May 1995

U. S. DEPARTMENT OF THE INTERIORBureau of Reclamation

Denver OfficeTechnical Services Center

Environmental Resources Team

Water Treatment Engineering and Research Group


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NANOFlLTRATlON OF A HIGH SALINITY

GROUNDWATER ON THE

HOPI RESERVATION

WilbertOdemNorthern Arizona University

Flagstaff, AZ

Contract No. 14253-CR-81-19540

Water Treatment Technology Program Report No. 3

May 1995

U. S. DEPARTMENT OF THE INTERIORBureau of Reclamation

Denver OfficeTechnical Services Center

Environmental Resources Team

Water Treatment Engineering and Research Group


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Bureau of ReclamationMission Statement

The mission of the Bureau of Reclamation is to manage, develop, and protectwater and related resources in an environmentally and economically soundmanner in the interest of the American public.

U.S. Department of the Interior

Mission Statement

As the Nations principal conservation agency, the Department of the Interiorhas responsibility for most of our nationally-owned public lands and natural.resoumes. This includes fostering sound use of our land and water resources;protecting our fish, wihilife, and biological diversity; preserving theenvironmental and cultural values of our national parks and historical places;and providing for the enjoyment of lifethrough outdoor recreation. TheDepartment assesses our energy and mineral resources and works to ensurethat their development is in the best interests of all people by encouragingstewardship and citizen participation in their care. The Department also has

a major responsibility for American Indian reservation communities and forpeople who live in island territories under U.S. Administration.

Disclaimer

The information contained in this report regarding commercial products orfirms may not be used for advertising or promotional purposes and is not tobe construed as an endorsement of any product or firm by the Bureau of

Reclamation.

The information contained in this report was developed for the Bureau ofReclamation: no warranty as to the accuracy, usefulness, or completeness isexpressed or implied.


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I pIDject was funded under Contract No. 14253-CR-81-19540 through the Bureau ofReclamations Water Treatment Technology Program. I would like to express myappreciation to Stan Hightower for his assistance throughout this project. In addition Iwould like to thank Tony Laban and the Facilities Management staff of the Hopi Juniorand Senior High School for their cooperation and patience during the on-site testing. TheHopi Tribes Natural Resources and Water Resources staff have also been very generouswith their time and information

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CONTENTS

1.0 Introduction ....................................................................................................... 7

1 .1 Background ........................................................................................... 7

1 .2 Purpose ofStudy ................................................................................... 1 1

2.0 Methodology ......................................................................................................2 .1 Preliminary Work ..................................................................................

2.2 Phase One .............;.. .............................................................................2.3 Phase Two ............................................................................................

2.4 On-Site ..................................................................................................

1 21 21 2131 6

3.0 Results and Discussion ....................................................................................... 1 6

3.1 Phase One Testing ................................................................................. 1 6

3.2 Phase Two Testing ................................................................................ 20

3.3 On-Site Testing ..................................................................................... 20

4.0 Preliminary Design Estimates ............................................................................ 2 3

4 .1 Design One ........................................................................................... 2 54.2 Design Two .......................................................................................... 2 5

4.3 Brine Disposal ...................................................................................... 2 5

4.4 Pretreatment ......................................................................................... 2 5

5.0 Discussions and Meetings ................................................................................. 26

5.1 Meeting with High School Teachers ..................................................... 26

5.2 Meeting withOfftcials ......................................................................... 266.0 Conclusions and Recommendations .................................................................. 27

Title Page .......................................................................................................... 1

Acknowledgements ............................................................................................ 2

Table of Contents .............................................................................................. 3

Glossary ............................................................................................................ 5

Summary ........................................................................................................... 6

Bibliography ....................................................................................................28

Appendices ...................................................................................................... 29

Appendix A- Phase One Testing Results ............................................. 30Appendix B- Phase Two Testing Results ............................................ 3 8Appendix C- On-Site Testing Results ................................................. 4 1Appendix D -Water Quality Analysis for Preliminary Design . . . . . . . . . . . . . . 4 5

Estimates

Page

3


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CONTENTS Contd.

List of Figures PageFigure 1 - Location of Study Site. .................................................................................. 8Figure 2 - Extent of Navajo (N) Aquifer On The Hopi and Navajo Reservations. ......... 1 0Figure 3 - Fmnt View Schematic of the Membrane Testing Apparatus. ........................... 1 4Figure 4 - Side View Schematic of the Membrane Testing Apparatus. ............................. 1 5Figure 5 -Results of Phase One Testing, 6/7/94 & 6/14/94. ............................................ 1 7Figure 6 - Results of Phase One Teqting, 6/28/94. ........................................................... 19igure 7 -Results of Phase Two Testing,g/9/94. ............................................................ 2 1Figure 8 -Results of On-Site Testing,g/22/94. ............................................................... 2 2figure 9-Con~ptul Design of a Full Scale Production System. .................................... 24

List of Tables

Table 1 - Water Quality of the Hopi High School Wells. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .._................. 9

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GLOSSARY

ACRONYMS/ABBREVIATIONS

anDBSAMCL.NN FntuO&M

psiR OSD1SRTDSTOCu v

At+Baca+Ccl-Q2C rFez+Fe*Ii+HCG-Hz0HZso4K+wMn2+NaN i

NQ-Si@so,

centimetersDaniel B. Stephens and Associatesmaximum contaminant levelNewtonsnanofi.ltrationIlephelometric turbidity unitoperations and maintenancepounds per square inchreverse osmosis

silt density indexsalt rejectiontotal dissolved solidstotal organic caxbonultraviolet

CHEMICAL FORMULAS

ahminum ionbariumcalcium ioncalcium carbonatechloride ionchloxinechromiumferrous ionferric ionhydrogen ionbicarbonate ionwatersulfuric acid

potassium ionmagnesium ionmanganese ionsodium ionIliCkdnitrate ionsilicasulfate ion

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SUMMARY

Commercial nanofiltration membranes were evaluated using a pilot scale testing apparatus fortreatment of a high salinity groundwater used as a drinking water source at the Hopi Junior/SeniorHigh SchooL Based on short term testing results (pressure requirements and permeate quality) twoof the membranes were se ted for longer term testing in the labomtory and on-site. Both of thesemembranes provided satisfactory treatment results which indicate that in a fuU scale system eithermembrane would produce a drinking water which meets Federal and State standards for TDS.

Hopi Tribal oflick have expressed interest in the results of this testing. This information will beused to help determine their response to the water quality problems at the school. Officials of theBureau of Indian Affairs, which is responsible for factities at the high school, also have expressedinterest in the results.

Preliminary estimates for a full scale system indicate that the system costs, instahation costs, andfirst year checkout and monitoring will cost approximately S 125,000, or about $2.50 per installedgallonper day, based on a 50,000 gallon per day need. Operation and maintenance costs areestimated at approximately $0.95 per 1000 gallons. Assuming a 20-year project life, the totalcosts are approximately $1.29 per 1000 gallons.


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1 .O INTRODUCTION

Included in the Bureau of Reclamations Water Treatment Technology Pmgrams objectives is thedevelopment of effective and economic treatment of impaired quality water for rural America.According to the Program Plan the program wiJlemphasize substantial participation by the non-Federal desalting and water treatment communities and by academia. TheProgram Plan alsoemphasizes the importance of technology transfer to communities that can benefit from informationdeveloped through Program-sponsored research.

1.1 Background

Three water supply wells at the Hopi Junior and Senior High School serve the needs of the schooland of the adjoining teachers: community. The school is located approximately 7 miles (11.3 km)east of the town of Polacca on the Hopi Reservation, or about 150 miles (241.4 km) northeast ofFlagstaff, Arizona (Figure 1). Appmximately 500-600 students attend the school andapproximately 150 residents live in the teachers community. Additionally, the water is used forlandscaping and fields maintenance at the school. The three wells feed into an elevated storagetank located behind the school.The water from these wells is high in TDS (total dissolved solids),with high concentrations of sodium, chloride, and sulfate. The water quality does not represent ahealth threat, but has presented problems due to objectionable taste and corrosion of pipes andwater heaters, and has caused problems with maintenance of the school football fieldDulaney (1989) stated that the Navajo, or N, Aquifer has two chemically distinct types of water:1) a calcimn bicarbonate type of water found in the north and west portions of the aquifer system,and 2) a sodium-chloride-sulfate. typeof water near the east and southeast of the aquifer system(where the high school wells are located). Dulaney suggested that the high salinity associated withthe sodium-chloride-sulfate waters may be due to mixing with either the overlying DAquifer orthe underlying cAquifer. A report by the Council of Energy Resource Tribes (1989) on waterquality issues on the Hopi reservation presented mean water quality data for water from the NAquifer, the DAquifer, the CAquifer, and the alluvial aquifer. Data fromthe high schoolwells more closely resembles mean water quality from the D Aquifer, a lower quality source thanthe N Aquifer. However, ranges of data show that the high school water chemistry falls withinmaximum values presented for the ?\I Aquifer (CERT. 1989). Daniel B. Stephens & Associates(DBSA) compiled the Report of Year Two Activities EPA 106 Water Quality AssessmentPmgnunfor the Hopi Tribe. In this report DBSA addressed the problem of high sahnityin thethmehigh school wells and one in the nearby community of Polacca. A summary of water andanalyses for the three high school wells was presented and is shown in Table 1. Figure 2 shows amap of the IV Aquifer on the Hopi and Navajo Reservations.DBSA suggests two reasons for the lower quality N Aquifer water observed in these wells: 1) anatural mixing of waters fromthe N Aquifer and the DAquifer due to either faulting in thearea, or more likely, to the correlation of the high salinity wells with the south-southeast boundaryof the N Aquifer, or, 2) mixing of waters from the two aquifers due to poor construction of thehigh school wells. DBSA identified four possible mitigation options for addressing natural ormanmade degradation of N Aquifer water quality at the Hopi High School:

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TABLE 1. Water Quality of the Hopi High School Wells.

parameter Avg. Concentration Concentration Rangemgn W

ArsenicBaIiWIlcadmiumchlumiumFlUOlideLeadMercuryNitrateSeleniumSilver

Alkalinity (as CaCOs)CalciumChlOlideCopperHardnessIronMagnesium

MangPotassium

PHSilica (as SiOdsodium

SulfateTDS

E.C. (Wcm)


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* Down-hole geophysical and water quality studies to attempt to identify the sourceof saline water,8 Rehabilitation of existing wells;8 Dlilling of new wells; Installation of a water treatment (reverse osmosis type treatment system).

Down-hole testing has been completed for Well 3with results inconclusive as to the amount ofseepage that may be occurring fromthe Dto the N Aquifer. At this time the Hopi Tribe isconsidering the three remaining options for mitigating the salinity problem.

1.2 Purpose of Study

The purpose of the present study is to investigate the technical feasibility of using nanofiltration totreat the water supplied by the three wells at the Hopi High School. This project was proposed in

response to the Bureau of Reclamations Request for Proposals for a preliminary research study ofpossible desalination demonstration projects under the Water Treatment Technology Program. A

previous study by researchers at Northern Arizona University (Speidel, 1993) contained data thatsuggested that nanofiltration technology might provide a more cost effective approach to treatmentthan reverse osmosis. Nanofiltration is typically used to remove chemical compounds greater thana molecular weight of 500 Daltons. The advantage it offers over reverse osmosis is loweroperating pressures, less strict pretreatment requirements, and a less concentrated reject brinewhich may alleviate disposal problems. Continued progress in membrane development has

produced commercially available membranes that approach reverse osmosis rejection capabilities,but operate at lower pressures typical for nanofiltration. This study identified and testedcommercially available nanofiltraiionmembranes for heating the groundwater supplied by thewells at the Hopi HighSchool.

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2.0 METHODOLOGY

2.1 Preliminary Work

Prior tothe actual testing of the membranes initial work had to be performed as described in thefohwingtzisks:* determination of source water quality;* identification and acquisition of candidate membranes:* constructfon of pilot-testing apparatus.

The membranes selected for evaluation were as follows:

FilmTecNF90FilmTecNF45Desalination Systems Desal-5Desalination Systems DKHydranautics PVD 1Fluid Systems TFCS (two tested for replicability evaluation identified as 5956 and 5957)Purification Products Company NF 500

These membranes were chosen on the following bases: 1) commercial availability; 2) availability ofthe appropriate size membranes (diameter and length) to allow testing with our apparatus. Other

membranes from other manufacuturers or distributors have been identified after the project testingperiod. It may be desirable to do preliminary testing of these membranes prior to final membraneselection.

2.2 Phase One

Short term testing of the nanofiltration membranes was carried out in Phase One evaluations. Eachmembrane was tested over a 24-hour period in which the feed water was made up in the laboratoryusing the source water chemistry as a recipe. Table 1 contains water quality information for theHopi High School wells obtained from the DBSA report. We used worst case water quality datafor our laboratory recipes, knowing that though this doesnt reflect typical water quality at the highschools, it was prudent to put the system under the most rigorous conditions. Analyses are still

needed for strontium, total and dissolved iron, and hetemtrophic plate count. These will beobtained prior to full scale design Both reject and product streams were recycled back into thereservoir after passage through the membranes. Samples were obtained at 0.5, 1, 2, 4, 8, and 24hours. The samples were analyzed for the following parameten:

0 Feed Water: Electrical conductivity, pH,flow, pressure, Cl, SO,-. Ca,Mg;

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2 Permeate: Electrical conductivity, pH,flow, pressure, Cl. Sod, Ca.Mg2+;3) Reject: Flow, electrical conductivity.

Analyses of anions was conducted on a Wescan Ion Chromatograph or a Dionex IonChromatograph equipped with a conductivity detector. Cations were measured on a Perkln ElmerAtomic Absorption Spectrophotometer equipped with a flame furnace or a Hach DR 3000Spectmphotometer. Temperature and pH were measured on a Coining Model 340 pH meter.Electrical conductivity was measured on an Orion Model 160 Conductivity Meter using an OrionModel 012210 Conductivity Probe.

Flow was maintained at approximately three gal/mm, (11.4 liters/rnin) per membrane at 10%recovery. The two best performing membranes were retested under Phase One conditions withadditional specific ions analyses performed. Additionally, each membrane was tested to determineproduct recovery versus pressure variation.

Figures 3 and 4 show schematic diagrams of the membrane testing apparatus. The apparatus

consisted of the feed reservoir, 5 pm cartridge pie-filters, the high pressure pump, four membranepressure vessels, flow meters for the permeate and reject streams, pressure gauges associated witheach pressure vessel, and associated valves and tubing. The influentwater was introduced fromthe reservoir and delivered to the membranes by the high pressure pump. Pressure gaugesupstream fromeach pressure vessel measured infIuent pressure to the membranes. Both thepermeate and reject streams were recycled back to the reservoir.

2.3 Phase Two

The two best performing membranes (based on water quality of permeate and pressurerequirements) from the Phase One testing underwent longer term testing to evaluate possibleperformance changes over time. The coniiguration of the testing apparatus and feed reservoir werethe same as in Phase One testing (Figures 3 and 4). The reject and product streams were againrecirculated back into the feed reservoir.

Phase Two testing was conducted over a tenday time period. Flow was maintained atapproximately three gaVmin (11.4 liters/min) and the membranes operated at 10% recovery.Samples were taken at 0.5, 1, 2,4, 8, and every 24 hours thereafter. The samples were analyzedfor the following parameters:

1) Feed Water: Electrical conductivity, pH, pressure, temperature, flow,Ca2, MgZ,Na, SO,-, and Cl.2 Permeate: Electrical conductivity, PH. pressure, temperature, flow.Ca2, gl Na, SO,-, and Cl.3 ) Reject: Electrical conductivity, pH. flow.

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RONTM W

0.5000x3

TO PSI GAGE ANDFLOW METERS

r5.0000

TO MANI FOLD:

47, sooo

0 00 0 0 00 0 0 00 0.

0 0l I I 0 046, SOOO

Y 1. 500I l o5000

PRESSURE GAGE 85, 0000x4

- LOWMFTER

FROM

FROM

62,- PUMP

8

AANI FOLD

' EED TANK

ure3. Front View Schematic of the Membrane Testing Apparatus.


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LEFT SIDE VIEW

TO FEEDTANK

FROM

MEMBRANES

MANI FOLD- .

TO MEMBRANESA ND PSI GA GE

FROMFEED

TANK

TO MANIFOLDI -

I

1 I 3.0000x4MEEEETO

BRANES X4

FLOW METERS

37.0000-PUMP

4

87.00 0

gure4. Side View Schematic of the Membrane Testing Apparatus.


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2.4 On-Sip3The original proposal described testing only up through Phase Two evaluations. However, duringthe course of the project., communicafion was maintahdwith the Hopi Natural Resources andWater Resources agencies. Arnold Taylor, Director of Natural Resources, and Nat Nutongla,Head of Water Resources, were kept informed of the projects progress. We explored with themthe possibility of testing the membranes on site at the high school and were put in touch with TonyLaban, Facilities Manager at the Hopi High School. Mr. Laban, who works for the Bureau ofIndian Affairs, arranged for us to have access to the pump house at Well l. We were able toinstall the testing apparatus with modiftcations to the facilitys electrical and plumbing connections.Therefore, with much help from thetribal officials and facilities management staff at theschool,we were able to accomplish on-site testing, which was additional to theoriginal project scope. itshould be noted that this testing was done at no additional cost to the Bureau of ReclamationApproximately ten trips to the Hopi Reservation (ca. 300 miles, 482.8 km, round trip) wererequired for the setup and testing.

The two membranes tested in Phase Two were evaluated, along with one more membrane chosenfromthe original group of membranes. The tests were run for three days under conditions similarto Phase Two testing, i.e. approximately three gallons per minute, with 10% recovery. Additionaltesting was done on one of the membranes with the testing equipment reconfigured to run in seriesas opposed to in parallel. Three membranes of the same make were used to more closely simulatefull scale operations. Samples were analyzed for the same parameters as in Phase Two testing.

3.0 RESULTS AND DISCUSSION

3.1 Phase One Testing

The Phase One testing occurred on 6/7,6/14, and 6128. As described in the methodology sectionthis work consisted of membrane evaluation over a 24hour period. Measured parameters includedflow (influent, permeate, reject), system pressure, conductivity, SO,-, CT. Ca. Mg2, permeaterecovery, and salt rejection. The runs conducted on 6/7 and 6/14 included all eight membranes,while the 6/28 run was a replicate run for the two best performing membranes as determined by thetwo previous tests.

Results for the 6/7 and 6/14 runs are shown in Figure 5 and Appendix A. Also included are datasheets for all of the runs. The figures and the following synopsis of the data are based on the 24hour sample taken for each membrane. All of the membranes exceeded 90% rejection of SO4-.The FtiTec NF90 and the PPCM NF-500 rejected greater than 95% of the influent Mg. whilethe Mg2 rejection by the other membranes was as follows: Ruid Systems membranes (5956 and5957) greater than 90%; the DeSal DK approximately 88%; the Hydranautics PVDl80 ; theDeSal DL less than 65%; and the FrlmTec NP45 approximately 55%. Similar rejections wereobserved for Ca2 rejection except for the PPCM NF-500 membrane which had about a 60%

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SULFATE REMOVAL 6128influent Concentration = 290.5 mgil

lC0

A

NFW SBNFSXI

CALCIUM REMOVAL 6128lnfluent Concentration = 24.5 mg/i

:PNFW LBNFSW

SODIUM REMOVAL 6128lnhent Concentration = 300.0 m@ l100

MAGNESIUM REMOVAL 6/28Muent Concentration = 16.3 mg/llrn

CHLORIDE REMOVAL 6128lnftuent Concentration = 714.1 mgil

I iNFQ3 SBNFSOO

T.D.S. REMOVAL 6l28lnttuent Concenldon =3410 &km

Figurt6. ResultsofP mseOneTesthg 28 4


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3.2 Phase Two Testing

The Phase Two testing was begun on WV94 and lasted for ten days. Specific ion analyses wereperformed through the 24-hour sample. Thereafter only pH. conductivity, temperature, pressure,and flows were measured, except for the Xl-day sample which received the full suite of analyses.Figure 7 and Appendix B show the results of this nm. A small increase in conductivity of theNP90 permeate (72 to 119 us/cm) and no significant increase in the conductivity of the NP-500was observed, suggesting little increase in the specific ion concentrations. During this longer termtesting temperature again increased, stabilizing between 37 and 38 C (-99 F). This temperatureincrease was accompanied by a corresponding decrease in operating pressure, from 100 psi to 89psi (68.9 to 61.4 N/cm) for the PPCM NF-500 and 128 psi to 99 psi (88.3 to 68.3 N/cm2) for theFilmTec NF90. However, as noted above, the permeate quality did not deteriorate for the NF-500membrane and only decreased slightly for the NF90 membrane.At the ten-day sample a total dissolved solids rejection (as measured by conductivity) of 93% was

measured for the PPCM NF-500 membrane and 97% for the FilmTec IW90. The last sample forwhich specific ions were measured, the 24hour sample, showed rejections similar to the otherPhase One tests. lheNF90 membrane rejected slightly more of the Cl, Na. and TDS, while bothmembranes rejected almost 100% of the Ca2, Mg2, and SO,-.Pressure measurements showed that the membrane cleaning performed after the 6/28 run hadmixed results. The PPCM NP-500 membrane appears to have recovered completely, with aninitial pressure reading of 100 psi (68.9 N/cm2) for an approximately 10% recovery. This iscomparable to the initial pressures observed in the first run on 6/7, approximately 106 psi (73.1N/cm2) for the same recovery. However, the FilmTec NF90 membrane cleaning doesnt appear tohave been as successful, with an initial pressure reading of 128 psi (88.3 N/cm2) for anapproximate 10% recovery. This is a decrease from the 6/28 initial reading of 138 psi (95.1N/cm), but still greater than the 108 psi (74.5 N/cm) recorded on the 6/7 run. Normally wewould simply replace the slightly fouled membrane with a new one, but as the NP90 is stillconsidered developmental, we were not able to obtain any more membranes until November 1994,which was too late to run the tests again. However, the results ate still useful in interpreting themembrane capabilities, as the fouling did not appear to be excessive.

Both membranes performed as well in the longer term testing as they did in the short term tests.The FilmTecNE90 produces a higher quality permeate, while operating at a similar pressure.

3.3 On-Site Testing

On-site testing was conducted at the Hopi High School using three membranes: FilmTec NF90,PPCM NF-500, and Fluid Systems TPCS (5956). Ideally we would have been able to run the testfor ten days. However, at the time we were conducting the tests hvo of the three wells were out ofservice for testing and repairs. Additionally, we had to dispose of the test water by simply drainingit into an adjoining field., which may have caused some misperceptions about wasting water in thisarid climate. Therefore, our extended run lasted slightly over two days. Figure 8 and Appendix Cshow the results of this run Samples were taken at 0.5, 1.0, 2.0.4.0, and 52.0 hours and analyzedfor the same parameters as in Phase One and Phase Two testing. In addition to using the actual

2 0


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SULFATE REMOVAL 819bduentConcenlralion=44Z 4m~w

CALCIUM REMOVAL 819lnflut3nt Concentration = 13.4 mgA

1oD

:mNFW SNPSOD

SODIUM REMOVAL W=wmlQ1

jllNFW BNFFXX)

MAGNESIUM REMOVAL 8l9nflu nt Concentration = 7.8 mg/l

rwwmBcm5ii4ho

0

lmNFS0 :CBNFEW

CHLORIDE REMOVAL 819lnnuentconcentra tion=10592mgfl

T.D.S. REMOVAL 819hlfbentco-on=364o~un

IIINFW SNFSm

Figure 7. Rmuitsof Phase Two Tat W9 94


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SULFATE REMOVAL 9122lnfluent Concentration = 164.7 mg/I

CALClUlU REMOVAL 9122influent Concentration = 10.0 mgIl

1W

0

SODIUM REMOVAL 9/22l nf tuentConcentr ati on=760.0 mgA

1oD

0

MAGNESIUM REMOVAL 9122Influent Concentration = 0.80 mgA

0

CHLORIDE REMOVAL 9122lnfluent concentration = 386.4mgA

T.D.S. REMOVAL 9122bdhmtConcent rat i on=247O~cm

Figure6. Resultsof0nateTesun&snask


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gmundwater we were able to avoid the temperature effects that affected the laboratory testing. Thetemperature remained at about 22C (71.6 F) throughout the test.The 52-hour samples were used to evaluate rejections for each of the membranes. The NF90membrane achieved close to 100% rejections of Mg, Na, S04, and TDS. Rejection of Ca2+ wasonly 90%, however the influent Ca concentration was low, so any measureable amount in thepermeate (in this case 0.9 mg/l)wilI make the rejection appear somewhat low. This also occurredfor Mg2 and Ca 2 rejection by the PPCM NF-500 membrane (0.25 and 1.1 mg/l respectively), butwhich calculates as only a 68% and 90 % rejection The PPCM NF-500 rejected almost 100% ofthe SO,- and Na, and approximately 98% of the Cl- and TDS. The Fluid Systems TFCSmembrane rejected almost 100% of the Mg, 91% of the SO,-, 75% of the Cl- and Ca2, about70% of the Na, and more than 80% of the TDS.

All of the membranes requited higher pressures to achieve a 10% recovery during the on-site teststhan in the lab tests. The reason for this is not known at this time, but these pressures are still wellbelow those used for reverse osmosis membranes. Further membrane testing on-site with new

membranes would allow examination of this disparity in operating pressures.Theon-site testswere very informative for a number of reasons. These tests provided confirmation of laboratorydata, showing that the two best perfonning membranes also performed well in the field The testsalso showed that laboratory simulation of the treatment process provides a reasonable estimation ofon-site performance. It was also very informative to be able to interact with the people who areinvolved in this issue and to become aware of the various perspectives. These people included theHopi Natural Resources and Water Resources staff, the Hopi High School facilities staff and BIApersonnel, and the teachers, staff and students of Hopi High School.

In summary, it appears that the two membranes identified in the laboratory testing FiiTec NF90and PPCM NF-500) also performed well in the on-site evaluations. The FilmTecNF90 produces ahigher quality product water, achieving a higher Cl- and TDS removal than the PPCM NF-500.Both membranes operate at similar pressures, so there appears to be no economic basis withrespect to energy consumption to choose one over the other. Therefore, looking purely at permeatequality it would appear that the FilmTecNP90 would be the preferred membrane.

4.0 PRELIMINARY DESIGN ESTIMATES

Prelimharydesign estimates were solicited from two firms based on the two best performingmembranes. Summaries of these designs are presented below. Figure 9 shows a conceptual designfor a full scale system. The designs were based on a product water flow of 50,000 gallons per dayusing a water analysis performed on a 10/06/87 sampling. The pilot scale testing used the high endof concentrations observed to look at worstcase influent water quality. The preliminary designsare based on a more typical water quality analysis. This water quality analysis is presented inAppendix D.

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Mf CRON FILTERAU WUbIIOlbI:50,000 ga lday60 -70% Rtcovc

- P R E S S U R E G A U G E X 5, 7 ip P R E S S U R E G A U G E X 5IGH-HIGH-

PRESSUREPRESSURE

MEMBRANE MODULE X7I I I I I

1PRODUCT

R E J E C T

Figure 9. Conceptual Dedgn of Full Scale Production Sydem.


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5.0 Discussions and Meetings

Meetings were held with users of the water and with appropriate tribal and agency representativesto discuss the water treatment testing. Results of these meetings and discussions axe presentedbelow.

5.1 Meeting with High School Teachers

The high schools teachers live in the community adjacent to the high school and are connected tothe high schools water system. They have expressed concern about the water quality and manyuse bottled water and individual treatment systems. Ihe project PI gave a presentation anddemonstration for the teachers. A number of the teachers later filled water containers with productwater from the pilot scale treatment system.. There was strong interest by the teachers in finding

some resolution to the water quality problems they were experiencing.

5.2 Meeting with Officials

A meeting was held on-site attended by representatives of the Hopi Tribe, the Bureau of IndianAffairs, the Bureau of Reclamation. the high schools facilities management staff, and NorthernArizona University. Arnold Taylor, Manager of the Hopi Tribes Department of NaturalResources, indicated that his Water Resources group was actively investigating solutions to thehigh schools water quality problems. Alternatives included redrilling of the production wells,establishment of a new well field in a different part of the N Aquifer, and on-site treatment.Stanley Hightower of the Bureau of Reclamation discussed funding for the project with Mr. Taylor

and with the representative of the Bureau of Indian Affairs, who oversees facilities operations atthe high schooL The result of the meeting and discussions was that there appears to be sufficientinterest by all parties to investigate possible funding for the full scale system if it is shown that itcan successfully address the water quality problems at the high school.

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6.0 CONCLUSIONS AND RECOMMENDATiONS

8 Short and long term laboratory testing identified two nanofiltration membranes thatsignificantly reduced the TDS. sodium, chloride, and sulfate levels of the feed water.

* Additional pilot-testing conducted on-site at the high school showed that the twomembranes achieved significant reductions in the above parameters with the actual groundwater from the high school wells. Projections based on the on-site testing indicate that at80% recovery the final product water would have an electrical conductivity of 275-325US/WI (-250-300 mg/l TDS).

* Test data and information provided by the two design companies indicate the productionsystem will require the nanofihration system and a pretreatment system similar to the

conceptual design shown in Figure 9. The capital cost of this system. including installationand civil works is estimated to be $83,000 to $105,000.

8 The 0 & M costs for this water, including membrane and cartridge replacement andelectrical power is approximately 0.95/1000 gallons or $17,340 per year. This does notinclude the capital costs of approximately $105,000 and the costs for monitoring andcheckout for the first year by Northern Arizona University of approximately $20,000. The

capital costs and first year checkout costs amount to approximately $2.50 per installedgallon per day (based on 50,000 gpd production). Assuming these costs are covered byappropriate grants and/or matching funds and dont require amortization, over a 20-year

project life this will raise the cost of the treated water to approximately $1.29 per 1000gallons

* Based on meetings with Tribal officials and the Bureau of Indian Affairs representativethere appears to be sufficient interest to investigate funding for the full scale system.

l Design of a pilot demonstration facility or full-scale system should be preceded byadditional analysis of pre-treatment needs, which would include at a minimum analysis ofwell water for S3. HPC, SDI, total and dissolved iron, and silica. Longer term on-sitetesting may also be beneficial for evaluation of pre-treatment needs. Additionally, brinedisposal options would have to be investigated for both technical and regulatory viability.

2 7


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32/58

Bibliography

Council of Energy Resource Tribes, 1989. HO S Water Ouality Management Promam.CERTm-89-2594; Project No. 106-2594-O.

Daniel B. Stephens and Associates, 1993. Renort of Year Two Activities EPA106 Water OualityentProgTam,

Dulaney, Alan R., 1989. . TheGeochemists of the N Aquifer Svstem. Navaio and Hopi IndianResemadom, Northeastern Arizona. Masters Thesis, Northern Arizona University, 1989.

Speidel, Harold, 1993. Personal Communication.

U.S. Department of the Interior, Bureau of Reclamation, Research and Laboratory ServicesDivision, 1992. Desaltiwz Technolopv Pnxram. FY 92-98.

28


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34/58

APPENDICES


35/58


36/58

Appendix A

Phase 1 Testing Results

30


37/58


38/58


39/58


40/58


41/58


42/58


43/58


44/58

Run of 6128194

pPC d NF600 IFlLMTEC NF90PRESSURE

70

0090loo710120130140150

RECOVERY0.15

0.180.210.260.29

0.320.380.410.46

PRESSURE RECOVERY70 a17

80 0.1990 0.24100 a29110 0.32120 0.39130 0.42140 0.48750 0.52

CONOU

250242

CONOUCTIWW130.7118.7106.798.8

92.588.6

6604.884.4

Run of 8/9/94fessumvukbionr8sults

PPCM NF500 FILMTEC NF90PRESSURE RECOVERY

70 0.18a0 0.2490 a3

100 0.35110 0.4120 0.48130 0.53140 0.58150 asi

CONOUCllVlTY PRESSURE RECOVERY CONOUCllVlTY 70 0.16 114.580 0.19 134.325 9 90 0.22 119.2247 100 0.29 105.4237 110 0.34 102.5231 120 0.38 97.8

130 0.42 93.6140 0.48 93.4P5 150 0.52 92.5


45/58


46/58

Appendix B

Phase 2 Testing Results

38


47/58


48/58

Run of 8msMMEMBRANE: MFG. PPCM MODElAt NF500

(WI ClPHConductivity us/cm

20.28.6

3640

Cations (mgil)Ca 13.40

lu g 7.80Na 546.0

HOUR

0.51.0

2.04.08.0

24.0REJECT 24 hr

48.072.096.0

120.0144.0168.0192.0216.0240.0

REJECT 240 hr

HOUR Ca MS Na SO 4 CI0.5 0.263 0.113 45.80 87.7 199.00

1.0 0.088 0.063 45.40 38.3 131.30

2 0 0.100 0.063 39.50 26.5 104.90

4.0 0,113 0.075 38.50 24.3 108.00

8.0 0.100 0.630 42.80 12.5 64.5024.0 0.050 0.100 44.80 21.4 76.10

REJECT 24 hr 13.80 8.20 600.0 506.5 3267.50

21.60

21.905::27.30

31.0032.6035.7037.3037.9037.7037.8037.7037.9038.5036.10

8.90

8.988.908.988.80

8.448.638.718.808.328.628.908.719.029.109.09

COND.u-m354.0224.0221.0214.0243.0

250.03970267.0261.0252.0249.0242.0240.0248.0247.0247.04120

PRESS.PM100.0100.0

100.096.0092.00

89.0089.0086.0087.0087.0087.0086.0088.0089.0089.0089.00

Anions (mg/l)s o 4 4 2 2 . 4 0

C l 1059 .20

FLOW @pm)PERM. REJECT0.300.30

0.290.280.29

0.280.280.280.280.280.280.270.260.260.260.27

3.10

3.703.003.002.90

2.902.902.802.802.802.80z-22:802.702.60


49/58

Run of 8/09194MEMBRANE: MFG. Film&c MODEIS NF90FEEDW TERTemperature (de9 C

PHConductivity us/cm)

20.0

8.6

caths mmCa 13.40Mg 7.80

Na 546.0

PERMEATEH O U R

0.5

1.0

2.04.08.0

24.0REJECT24hr48.072.0

96.0120.0

144.0168.0

192.0216.0

240.0

RWECT24Ohr

HOUR ca

0.5 b/d1.0 b/d

2.0 b/d4.0 b/d

8.0 b/d24.0 b/d

REJECT24hr 10.40

TEMP.

(deg cl21so21.8022.70.24.2027.40

32.2032.5035.5037.30

38.0038.00

37.6037.5037.80

38.50

36.70

PH9.089.08

9.17

9.078.85

8.898.748.838.74

8.588.76

8.798.829.009.04

9.29

M 90.050.01

0.030.03

0.010.01

5.85

COND.

wm72.369.1

72.9

78.091.794.0

3990108.9111.9114.3

173.5

108.2110.1119.2

121.1119.1

4130

PRESS.

(psi)128.0128.0

129.0

124.0117.0

100.0

100.097.097.0

97.097.0

98.0

98.099.0

99.099.0

PERM. REJECT

0.26 2. 50

0.26 2.50

0.27 2.50

0.27 2.40

0.27 2.50

0.26 2.50

0.26 2.50

0.27 2.40

0.27 2.50

0.27 2.50

0.27 2.50

0.26 2.40

0.25 2.50

0.25 2.50

0.25 2.50

0.25 2.50

N a Cl13.8 5.9 17.412.3 30.3 22.913.3 3.8 20.714.1 n a n/a16.2 3.5

60.2

16.8 4.4 33.5916.0 372.9 868.1

Anions mg/lSO4 420.50

Cl 1059.20

FLOW gpm


50/58

Appendix C

On-Site Testing Resu Its


51/58


52/58

MEMBRANE: MFG. PPCM MODE 3 NF500FEEDWATER Cations (mgll)Temperature (deg C) 21 .l C a 10.0PH 8.6 Mg 0 . 8condudivity (us/cm) 2470 N a 760.0

Anions (mg/l)SO4 164.7

Cl 386.4

PERMEATEH OU R TEMP.

(deg cl PHCOND. PRESS.

(us/cm) @SOfiovv him)

PERM. REJECT

0 . 30 2.800.30 2.800.30 2.800 2 9 2.70

0.29 2.70

Cl

9 2 0

11.507 . 90

6 . 00

8 . 2

0.5 -2220- 8.75 58.31.0 21.90 7.85 66 . 72.0 22.60 8.05 33.24.0 22.40 8.08 46 . 6

52.0 n/a n/a n/aHOUR Ca fw N a

0 .5 1.10 0.10 3.301.0 1.10 0.10 3.702 .0 1.20 b/d 1.304 .0 1 2 0 b/d 0.60

52.0 1.00 0.25 4.63

140. 0137.0140.0140.0

140.0

S O 4

0.91

0.960.69

0.57

15.90

Run of g/22/94MEMBRANE: MFG. Fluid Svstems MODEL 5956FEEDWATERTemperature (deg C) 21 .lPH 8.63Conduct ii us/cm) 2 4 7 0

PH

Cations(mgll)C a 1 0 . 0

M g 0 . 8

N a 760 . 0

Anions (mgll)SO4 164.7

C l 3 8 6 . 4

PERMEATEHOUR TEMP.

0.5

1.02 . 04 . 0

52.0

w2 2 2 022.3022.60n/a

aw gpmP ER M. REJECTCOND. PRESS.

wm 563.0 181.0588.0 182.0491 .o 181.0389.0 179.0453.0 185.0

8.457.877.888.03n/a

026 2.300 2 6 2.300 .27 2.30

0 .26 2.600 2 4 2.30

HOUR Ca Mg Na0.5 12.50 2.50

1.0 5.00 b/d2.0 5.00 bid

4 . 0 5.00 b/d52.0 2.50 b/d

Cl

305.0 168.0

270.0 37.40

267.5 2 6 2 0

220.0 27.10235.0 14.70

97 . 80

110.40

86.0059 . 80

98.10


53/58

Runof msMEMBRANE= MFG. FilmTec

WwClP H

conductivity (us/cm)

PERMEATEHOUR

0.51.02. 04. 0

52.0

HOUR ca 0.5 0.90 bid1.0 1.10 W d

2. 0 1.00 W d4.0 1.10 W d

52.0 1.10 W d

21.18.63

2470

F&i21.9022.6022.50n/a

PH0.078.030.208.35n/a

MODEIS NF90catbns mmca 10.0

Mg 0.8

Na 760.0

COND.

Wy)

ii-f:33:225.9

PRESS.

(Psi)158.0

160.0 150.0

150.0n/a

Na SO4

0.50 0.640.60 0.552.60 0.433.80 0.364.30 0.49

FLOW cm)REJECTPERM.

0.29 2.800.29 2.600.28 2.800.27 2.70n/a n/aCl

4.504.503.502.603.50

nI ons owvs o 4 164.7

Cl 386.4


54/58

NF70 NF500

Run of g/22/94Pressure variation results

PRESS70

8090

100110

120130140

150160

170180

190200

( RECOVERY) ( RECOVERY)

REJECT PERM PRESS REJECT PERM4. 70 0. 09 70 4. 20 0. 12

4. 50 0. 10 80 4. 00 0. 134. 36 0. 13 90 3. 80 0. 16

4. 10 0. 15 100 3. 60 0. 19

3. 96 0. 18 110 3. 40 0. 21

3. 70 0. 19 120 320 024

3. 46 0. 21 130 290 028

3. 10 0. 25 140 2. 70 0. 30

280 0.28 i SO 250 0133260 0. 30 160 230 0.37

230 0. 32 170 210 0.39

1. 90 0. 34 180 1. 80 0. 42

1. 60 0. 38 190 1. 50 0. 45

1. 10 0. 39 200 1. 10 0. 48


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56/58

Appendix D

Water Quality Analysis for Preliminary Design Estimates

45


57/58


58/58

Inorganic Chemical Analysis

Lab Name and Address:

Western Technologies, Inc.3737 EasstBroadway Road

P.O. Box 21387Phoenix, AZ 85038

Hopi JrfSr.High School -Well No. 3 1O/06/87Contaminant Name Analvsis Results me/l

RrseniCBariumcadmium

alromiumFhlOlide

MercuryNitrates

seleniumSilveri4lkahityCalciumChlOliCkCopperHardnessIronMagnesium

Manganese

P HsbdilmlSulfateTDS

4.02

co. 1

co.005

CO.02

2.9

< 2CO.001co.1CO.005

CO 02260

8

760CO 05

28

0.3

7

CO 058.9

810

3202180

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Nanofiltration of a High Salinity Groundwater on the Hopi Reservation

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