Treatment of Oil and Gas Wastewater in Colorado: Assessment of a Hybrid

Membrane System

Stephanie M. Riley, Tzahi Y. Cath Department of Civil and Environmental Engineering

Colorado School of Mines

2015 Annual Water Resources Conference November 18, 2015, Denver, CO

Personal Bio

Newman University B.S. Biology (2013)

Raymond Oil Co., Inc. Colorado School of Mines

M.S. Environmental Engineering Science (2015)

PhD Candidate (Current)

Presentation Overview

Unconventional oil and gas (O&G) development in the U.S.

Water management: recycling and reuse Advanced processes: bio-physical treatment

Biologically-active Filtration (BAF) Theory and application

Membrane Treatment Ultrafiltration (UF) Nanofiltration (NF)

Results and conclusions

O&G Development in the U.S.

Figure courtesy of Vengosh et al., 2014. Data obtained from Ceres analysis using WRI’s Aqueduct Water Risk Atlas.

Water Management: Inject or Reuse?

Estimated percent of recycled/reused water in main O&G basins

Fresh water use varies: 20-95%

Recycled/reused water use: often < 5%

Tinker, S. W., 2012. Oil & gas water use in Texas: update to the 2011 mining water use report, from http://www.twdb.state.tx.us/publications/reports/contracted_reports/doc/0904830939_2012Update_MiningWaterUse.pdf

Play / Region Type 2012

Permian Far West Recycled/reused 0% Brackish 80% Fresh 20%

Permian Midland Recycled/reused 2% Brackish 30% Fresh 68%

Anadarko Basin Recycled/reused 20% Brackish 30% Fresh 50%

Barnett Shale Recycled/reused 5% Brackish 3% Fresh 92%

Eagle Ford Shale Recycled/reused 0% Brackish 20% Fresh 80%

East Texas Basin Recycled/reused 5% Brackish 0% Fresh 95%

Produced Water Treatment Challenges Challenges

Salinity: ranging from < 10,000 ppm to >100,000 ppm Organics: Hydrocarbons, carbohydrates (gel), oil, grease Inorganics: silicates, borates, calcium, iron, NORM Varying volumes and characteristics

Treatment technologies Gravity separation, chemical treatment, hydrocyclones,

dissolved-air flotation, filtration, membranes (UF, NF, RO, FO), oxidation, air-stripping

Common hurdles… Need for (thorough?) pretreatment Biological processes?

Potential Treatment of O&G Wastewater: Biological and Membrane Treatment

Biological Treatment Removal of organic constituents Rejection of colloidal material Pretreatment for UF/NF reduced membrane fouling

Membrane Treatment Rejection of colloidal material Inorganics removal and desalination

Potential treatment of produced water (PW) for reuse in fracking operation, irrigation, livestock watering, streamflow augmentation

Biofiltration and Membrane Treatment

Processes

1

Biologically-Active Filtration (BAF) Attachment and growth of biofilm on filter media Biofilm consists of microorganisms and extracellular

polymeric substances (EPS) Microorganisms utilize oxygen and carbon sources to

degrade organic matter

Applications Industrial/municipal wastewater treatment Drinking water treatment

bacteria organic matter + O2 + nutrients CO2 + NH3 + C5H7NO2 + other end

products

(1) Photo courtesy of Nature Education

new cells

Ultrafiltration (UF) and Nanofiltration (NF) UF

Low-pressure membrane process Separates particulate matter (including microorganisms)

and macromolecules from impaired feed streams

NF Higher-pressure membrane process Desalination and softening* Produces high quality permeate suitable for reuse in

industrial or indirect potable applications

* For in-basin reuse in fracking operations, most operators typically require removal of suspended solids, microorganisms, hardness

BAF + UF + NF/RO

Scope of Research Treatment objectives

Optimization of BAF as a pretreatment through: Microbial acclimation and biofilm conditioning Biodegradation of organics Continuous feed of PW/FFB

Reduce fouling propensity of UF and NF membranes Characterization of effluent/permeate at all treatment

stages Evaluate membrane performance (rejection, water flux,

permeability) Optimize backwashing and chemical cleaning

Materials and Methods: BAF Granular activated carbon (GAC) media, 30- 36” depth Aeration Ambient temperature Feed water: PW, FFB Hydraulic loading rate = 1.0 gpm/ft2

Empty bed contact time: Batch mode: 20 min Continuous mode: 24- 48 hrs

Analyses Chemical oxygen demand (COD), dissolved oxygen (DO), dissolved

organic carbon (DOC), ion chromatography (IC), inductive coupled plasma (ICP), turbidity

Materials and Methods: UF

Hollow fiber membranes Membrane modules fabricated in the lab DOW PVDF capillary membranes (62.34 cm2) Koch Puron® PES capillary membranes (125 cm2)

Operation Feed Pressure: 5-7 psi or permeate vacuum Temp: 20 ± 0.5 °C Cross-flow velocity: ~17 cm/s Backwash (BW): UF permeate Chemical-enhanced backwash (CEB): NaOH

Integrity/ Permeability tests

Materials and Methods: NF

Membrane: DOW NF90 Active area: 139 cm2

Operating conditions Feed: BAF + UF treated Feed volume: 5 L batches Pressure: 150- 300 psi Flow rate: ~1.25 LPM Temp: 20 ± 0.25 °C

Membrane compaction before testing Cleaning

NaOH/HCl cycles

Materials and Methods: Feed water

TDS: 12,000 to 30,000 mg/L DOC: 200 mg/L to 2500 mg/L COD: 500 mg/L to 12,000 mg/L Alkalinity: >600 mg/L as CaCO3

Results and Discussion: BAF, UF, NF

BAF: DJ Basin PW Batch- mode, 10 L, raw

Decreased DOC adsorption Increased DOC degradation rates

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Continuous mode: 48 hr HRT 87% DOC removal Steady-state after ~150 hours

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BAF: Piceance Basin PW Continuous Mode:

7 mL/min raw PW makeup = 24 hr HRT 67% DOC removal (remaining is recalcitrant) Steady-state after 5 hours Effluent collected for UF

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76% 74%

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To UF

Ultrafiltration: Piceance Basin PW

10 L, 6 psi, CEB at 50% flux decline 1.57 NTU feed 0.3 NTU permeate High flux recovery after CEB

DOW hollow fibers BAF treated Piceance PW, 10 mg/L DOC

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CEB42%

CEB71%

2 x 10 L batches, 6 psi, BW every 6 hrs, CEB at 40 and 80 hrs

0.92 NTU feed 0.16 NTU perm Flux maintained > 20 LMH

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CEB50%

CEB68%

CEB82%

Nanofiltration: Piceance Basin PW

Permeate Flux. “A”= acid/base cleaning, “B”= feed replenishment (150 and 200 psi tests)

Tests at 150, 200, 250, and 300 psi ~1.25 LPM, 5 L batches Feed: TDS= 12 g/L, TOC= 9.6 mg/L,

TN= 7.3 mg/L, turbidity= 0.9 NTU

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BAF: DJ Basin PW

Continuous mode: 3.5 ml/min raw feed dose = 48 hr HRT 87% DOC removal Steady-state after ~150 hours Effluent collected for UF

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Ultrafiltration: DJ Basin PW DOW fouling experiment:

Feed: 10 L, 1.07 NTU Constant flux: 35-40 LMH BW: every 7 min for 60 sec CEB: after 48 hours operation Turbidity removal to 0.14 NTU

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Koch fouling experiment: Feed: 2x 10 L, 1.18 NTU Constant flux: ~20 LMH BW: every 5 min for 25 sec CEB: after 40, 60, 76, 80 hours Turbidity removal to 0.34 NTU

Nanofiltration: DJ Basin PW

Permeate Flux. “A”= acid/base cleaning, “B”= feed replenishment

Tests at 150, 200, 250, and 300 psi ~1.25 LPM, 5 L batches Increased flux/rej with pressure Feed: TDS= 14 g/L, TOC= 32 mg/L,

TN= 8.7 mg/L, turbidity = 0.45 NTU

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Summary: DJ Basin PW Pretreatment NF Permeate

Analyte Raw Feed BAF effluent/ UF feed

UF perm/ NF feed 150 psi 200 psi 250 psi 300 psi

turbidity 19.6 1.07 0.445 0.096 0.086 0.078 0.062 COD 1157 132 125 0.000 0.000 0.000 0.000 DOC 385 40.3 31.6 1.61 1.21 1.61 1.35 TN 26.6 13.3 8.72 2.27 1.98 1.29 1.02 B 9.85 9.85 7.28 6.33 5.18 4.17 3.71

Ba 2.52 2.52 4.80 0.072 0.056 0.026 0.015 Ca 43.3 43.3 41.9 0.841 0.515 0.27 0.220 K 526 526 520 119 61.3 46.1 37.3 Li 3.95 3.95 4.10 0.586 0.299 0.248 0.196

Mg 11.5 11.5 9.55 0.155 0.104 0.045 0.024 Na 4968 4968 4432 776 400 344 271 P 0.724 0.724 0.736 0.017 0.026 0.025 0.006 S 10.6 10.6 5.20 0.085 0.063 0.204 0.028 Si 5.63 5.63 3.31 0.292 0.188 0.454 0.182 Sr 4.98 4.98 7.59 0.113 0.080 0.022 0.016 Cl 8919 8919 8858 1595 785 717 568 Br 62.3 62.3 55.1 13.1 6.76 6.06 4.89

Anions (mg/L) 8982 8982 8913 1608 792 723 573 Cations (mg/L) 5588 5588 5036 903 468 397 312

TDS (mg/L) 14569 14569 13950 2512 1260 1120 885 % TDS Removal N/A 0.0% 4.3% 82.0% 91.0% 92.0% 93.7%

BAF: DJ Basin Frac Flowback Continuous mode:

3.5 ml/min raw feed dose 48 hr HRT

Increasing DOC/COD, low DO Optimizing aeration…

Batch mode: Feed tank aeration:

BAF 1: 0.5 LPM

Column aeration BAF 2: 0.05 LPM BAF 3: 0.1 LPM BAF 4: 0.25 LPM

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BAF: DJ Basin Frac Flowback Continuous mode:

4 columns in series 48 hr HRT 0.05 LPM aeration (BAF 1 & 3) 79% DOC removal Steady-state after 72 hours

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Ultrafiltration: DJ Basin Frac Flowback Feed: 2x10 L batches, turbidity = 24 NTU, COD = 277 mg/L

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DOW UF Membrane Constant flux: ~40 LMH BW: every 5 min Permeate turbidity 0.2 NTU Permeate COD 233 mg/L

Koch UF Membrane Constant flux: ~ 20 LMH BW: every 5 min Permeate turbidity 0.4 NTU Permeate COD 237 mg/L

Nanofiltration: DJ Basin Frac Flowback Tests at 200, 250, and 300 psi ~1.25 LPM, 5 L batches Feed: TDS= 29 g/L, TOC= 57 mg/L,

TN= 12 mg/L, turbidity = 0.59 NTU Nearly 2x the TDS and TOC of DJ PW

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Summary: DJ Basin Frac Flowback 3D fluorescence

Removal of dissolved organic matter a) Untreated flowback b) BAF effluent c) NF permeate- 200 psi d) NF permeate- 300 psi

a)

b)

c) d)

Conclusions BAF

Biofilm can be conditioned to treat PW and FFB Effectively removes organic matter and colloidal material

Batch mode PW: achieves > 90% DOC removal in 24 hours Batch mode FFB: achieves > 75% DOC removal in 50 hours Continuous mode: efficiently treats PW, FFB more challenging…

NF High rejection of organics and inorganics Minimal flux decline at 150 and 200 psi

UF Achieves > 95% water recovery Turbidity removal to < 0.1 NTU BW/CEB maintain and recover permeability

Future Research Improve efficiency of BAF

Treatment of FFB in continuous mode Pilot-size BAF being constructed Microbial analyses

Reduce membrane fouling (UF and NF) Optimization of chemical cleaning/backwashing Membrane characterization Membrane selection

Characterization of recalcitrant organics

Acknowledgements NSF/Sustainability Research Network US Department of Energy/RPSEA Aqwatec labmates