considerations for brackish groundwater use as a water supply for small water systems and...

Considerations for Brackish Considerations for Brackish Groundwater Use as a Water Supply Groundwater Use as a Water Supply

for Small Water Systems and for Small Water Systems and MunicipalitiesMunicipalities

Eddie C. Livingston, MSCE, Eddie C. Livingston, MSCE, P.E.P.E.

Livingston Associates, P.C.Livingston Associates, P.C.NM Brackish Groundwater Aquifer Assessment WorkshopNM Brackish Groundwater Aquifer Assessment Workshop

Albuquerque, NMAlbuquerque, NM

January 15, 2004January 15, 2004

LIVINGSTON ASSOCIATES, P.C.Consulting Engineers


Saline GW in NMSaline GW in NM

20% fresh <1,000 ppm TDS20% fresh <1,000 ppm TDS 50% brackish water 1,000 - 3,000 TDS50% brackish water 1,000 - 3,000 TDS 25% brackish water 3,000 - 10,000 TDS25% brackish water 3,000 - 10,000 TDS 5% saline water >10,000 ppm TDS5% saline water >10,000 ppm TDS

– (source: NM Bureau of Mines & Mineral (source: NM Bureau of Mines & Mineral Resources, 1965, Mineral and Water Resources, 1965, Mineral and Water Resources of New Mexico: Bulletin 87)Resources of New Mexico: Bulletin 87)


Establish Water Quality Establish Water Quality GoalsGoals

Meet USEPA/NMED primary and Meet USEPA/NMED primary and secondary drinking water standardssecondary drinking water standards

TDS <500 mg/LTDS <500 mg/L Sulfate <250 mg/LSulfate <250 mg/L or will <1,000 mg/L TDS be or will <1,000 mg/L TDS be

acceptable?acceptable? Match current quality?Match current quality? End user decisionEnd user decision


Desalting TechnologiesDesalting Technologies

Reverse Osmosis (RO) - Pressure driven Reverse Osmosis (RO) - Pressure driven membrane ion separation processmembrane ion separation process

Electrodialysis Reversal (EDR) - Low Electrodialysis Reversal (EDR) - Low voltage electrical ion separation processvoltage electrical ion separation process

Ion Exchange (IX) - Replaces select ions Ion Exchange (IX) - Replaces select ions for another (sodium for hardness)for another (sodium for hardness)

various thermal (distillation) processesvarious thermal (distillation) processes New technologiesNew technologies


RO MembraneRO Membrane

FEED SIDE(HIGH PRESSURE)

SALTS SALTS

MEMBRANE

PERMEATE SIDE(LOW PRESSURE)


Ion RejectionIon RejectionTypical Reverse Osmosis Membrane Ion RejectionsIon Reject Ion Reject Ion Reject Ion RejectAluminum 99%+ Chloride 95-97% Magnesium 96-98% Silver 85-97%Ammonium 88-95% Chromate 90-98% Manganese 98-99% Sodium 95-98%Arsenic 94-96% Chromium 96-98% Mercury 96-98% Strontium 96-99%Barium 96-98% Copper 98-99% Nickel 98-99% Sulfate 99%+Bicarbonate 95-96% Cyanide 90-95% Nitrate 93-96% Sulfite 98-99%Borate 35-70% Ferrocyanide 99%+ Phosphate 99%+ Thiosulfate 99%+Boron 60-70% Fluoride 94-96% Potassium 95-97% Zinc 98-99%Bromide 94-96% Hardness 96-98% Selenium 96-98%Cadmium 96-98% Iron 98-99% Silica 85-90%Calcium 96-98% Lead 96-98% Silicate 95-97%


RO TermsRO Terms

Feed water (BW supply)Feed water (BW supply) Permeate (product) treated waterPermeate (product) treated water Brine (concentrate) rejected salt Brine (concentrate) rejected salt

streamstream Recovery: percent of product water Recovery: percent of product water

to feed water (ie; if feed = 100 to feed water (ie; if feed = 100 gallons, and product = 75 gallons gallons, and product = 75 gallons then recovery is 75%)then recovery is 75%)


Example RO PerformanceExample RO Performance

FeedFeed TDS = 2,250 mg/LTDS = 2,250 mg/L Cl = 189 mg/LCl = 189 mg/L SOSO4 4 = 1,220 mg/L= 1,220 mg/L Ca = 353 mg/LCa = 353 mg/L Hard = 1404 mg/LHard = 1404 mg/L pH = 7.3pH = 7.3

ProductProduct 25 mg/L25 mg/L 5 mg/L5 mg/L 5 mg/L5 mg/L 3 mg/L3 mg/L 12 mg/L12 mg/L 6.06.0


WELL

HIGH PRESSUREPUMP

PRE-FILTERS

CHEMICAL FEED (ACID, SCALE

INHIBITOR)

RO ARRAY

BRINE DISPOSAL

RO

PERMEATE

POST-TREATMENT

TO DISTRIBUTION

WELL BY-PASS

FOR BLENDING


Horizon City 6 MGD ROHorizon City 6 MGD RO


MEMBRANE SCALINGMEMBRANE SCALING

Scale formation on Scale formation on membrane surfacemembrane surface

Sparingly soluble Sparingly soluble salts (CaSOsalts (CaSO44, BaSO, BaSO44))

Will cause “tail-end” Will cause “tail-end” membrane scalingmembrane scaling

Increased operating Increased operating pressure and pressure and decrease in salt decrease in salt rejectionrejection


BWRO Problem SaltsBWRO Problem Salts

CaSOCaSO44

BaSOBaSO44

SrSOSrSO44

CaCOCaCO33

CaFCaF

FeFe MnMn AlAl SiOSiO22


Concentrate DisposalConcentrate Disposal

Concentrate 3X to 5X feed TDSConcentrate 3X to 5X feed TDS Concentrate flow 20% to 50% feedConcentrate flow 20% to 50% feed Sewer system to WWTPSewer system to WWTP Deep well injectionDeep well injection Evaporation ponds, playasEvaporation ponds, playas Concentrated for zero-dischargeConcentrated for zero-discharge Beneficial uses, land applicationBeneficial uses, land application


RO EquipmentRO Equipment

Pre-engineered “skid” mounted incl. Pre-engineered “skid” mounted incl. pumps, pre-filters, chem feed, RO pumps, pre-filters, chem feed, RO array and controlsarray and controls

For small systems from 15,000 gpd For small systems from 15,000 gpd to around 500,000 gpdto around 500,000 gpd

Can be containerized or placed in a Can be containerized or placed in a buildingbuilding

Modular for expansionModular for expansion


Relative Desalination Costs vs. Plant Capacity(AWWA)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

1 5 10 20 40

Plant Capacity Factor

Co

st

Fa

cto

r

Unit Capital Cost

Unit O&M Cost


O&M CostO&M Cost

PowerPower 10% to >50%10% to >50% LaborLabor 80% to <15%80% to <15% MembranesMembranes <15% to 25%<15% to 25% ChemicalsChemicals <10% to >25%<10% to >25%

Concentrate disposalConcentrate disposal Higher TDS, greater O&MHigher TDS, greater O&M


Desalination Cost Desalination Cost ConsiderationsConsiderations

Target BW in lower TDS range (<5,000)Target BW in lower TDS range (<5,000) Maximize recovery, utilize scale inhibitorMaximize recovery, utilize scale inhibitor Maximize blending potential, integrateMaximize blending potential, integrate Evaporate or land apply concentrateEvaporate or land apply concentrate Use shallow wells near roads and powerUse shallow wells near roads and power Gravity flow delivery system, exist routeGravity flow delivery system, exist route Use economies of scale, regionalUse economies of scale, regional


BGW Quality Data NeededBGW Quality Data Needed

TDSTDS ConductivityConductivity pHpH TempTemp Major Cations/AnionsMajor Cations/Anions Fe/Mn/Al/SiFe/Mn/Al/Si


Possible StrategiesPossible Strategies

ID potential users, small and largeID potential users, small and large Evaluate opportunity for Regional Evaluate opportunity for Regional

supply where possiblesupply where possible Characterize BW resources within a Characterize BW resources within a

practical radius, power and routespractical radius, power and routes Rank based on quality, yield, volumeRank based on quality, yield, volume Perform RO pilot study for costing Perform RO pilot study for costing


Ft. Stockton, TexasFt. Stockton, Texas

6 MGD RO Plant (3 MGD blend)6 MGD RO Plant (3 MGD blend) TDSTDS 16001600 800800 mg/Lmg/L SulfatesSulfates 430430 215215 mg/Lmg/L HardnessHardness 600600 300300 mg/Lmg/L RecoveryRecovery 80%,80%, brine to WWTPbrine to WWTP CostCost = $0.30/kGal (blended)= $0.30/kGal (blended)


Ft. Stockton 6 MGD ROFt. Stockton 6 MGD RO


WSMR Stallion Site EDRWSMR Stallion Site EDR

150,000 GPD150,000 GPD Feed TDS 3,600 ppmFeed TDS 3,600 ppm Product TDS 500 ppmProduct TDS 500 ppm Recovery 65%Recovery 65% Costs $2.00 per KgalCosts $2.00 per Kgal Brine evaporated in Brine evaporated in

pondpond


Alamogordo, NMAlamogordo, NM

6 MGD RO Plant; expand to 13 MGD.6 MGD RO Plant; expand to 13 MGD. TDS of GW 2,200 mg/L to 800 mg/LTDS of GW 2,200 mg/L to 800 mg/L Blend 60% RO to 40% GWBlend 60% RO to 40% GW Recovery approx. 84%, brine to Recovery approx. 84%, brine to

evap.evap. Capital Cost = $8 M (plant/pond)Capital Cost = $8 M (plant/pond) Delivered Cost = $0.65/kGalDelivered Cost = $0.65/kGal


Gallup (White Cliffs)Gallup (White Cliffs)

15,000 GPD RO Plant15,000 GPD RO Plant TDS*TDS* 3,0003,000 150150

mg/Lmg/L RecoveryRecovery 85%,85%, brine to brine to

WWTPWWTP Capital CostCapital Cost = $50,000= $50,000

* - varies* - varies


Questions?Questions?

considerations for brackish groundwater use as a water supply for small water systems and...

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