# Key Considerations for Frac Flowback /

Produced Water Reuse and Treatment

NJWEA Annual Conference

– Atlantic City, NJ

May 2012

# Today’s Agenda

• Overview of Hydraulic Fracturing Process



## • Water Quality

• Treatment Alternatives

2

# Hydraulic Fracturing

Source: ALL Consulting. Handbook on Coal Bed Methane Produced Water: Management and Beneficial Use Alternatives, July 2003. 

## • Frac Method: Typically

slick water frac

• Wells: 4 to 8 wells per pad



## • Frac Water Volume: 4 to 6

million gallons per well

(95k to 142k bbl)



## • Flowback : 15

– 35% return

3

# Composition of a Fracturing Fluid

• Fracturing solution consists of sand and water

• Additives include biocides, corrosion inhibitors, O2 scavengers,

friction reducers, surfactants, etc.

4

Reference: All Consulting 2009

# Frac Flowback Water Quality

All values in mg/L

Parameter Feed Water Flow back

pH 8.5 4.5 to 6.5

Calcium 22 22,200

Magnesium 6 1,940

Sodium 57 32,300

Iron 4 539

Barium 0.22 228

Strontium 0.45 4,030

Sulfate 5 32

Chloride 20 121,000

Methanol Neglible 2,280

TOC Neglible 5,690

TSS Neglible 1,211

TDS <500 182,273

5

# Typical Flowback Characteristics

The longer Frac

water is in the

formation, the

higher the TDS

levels may

become.

Source: Siemens AG 2009 6

# Wide Variation in Frac Flowback Chemistry

Parameter Frac 1 Frac 2 Frac 3 Frac 4

Barium 7.75 2,300 3,310 4,300

Calcium 683 5,140 14,100 31,300

Iron 211 11.2 52.5 134.1

Magnesium 31.2 438 938 1,630

Manganese 16.2 1.9 5.17 7.0

Strontium 4.96 1,390 6,830 2,000

TDS 6,220 69,640 175,268 248,428

TSS 490 48 416 330

COD 1,814 567 600 2,272

7 All values in mg/L

Ref: ProChemTech International, Inc.

# Total Dissolved Solids from the Produced

Water Database in the United States

• Typical Produced Water TDS Levels

– Selected Areas

– Powder River CBM

– 1,200 mg/l

– San Juan CBM

– 4,500 mg/l

– Greater Green River

– 8,000 mg/l

– Eagle Ford Shale

– 20,000 mg/l

– Fayetteville Shale

– 25,000 mg/l

– Barnett Shale

– 60,000 mg/l

– Woodford Shale

– 110,000 mg/l

– Haynesville Shale

– 120,000 mg/l

– Permian Basin

– 140,000 mg/l

– Marcellus Shale

– 180,000 mg/l

Source: USGS 8

# Key Water Management Concerns

• Wasting water

and general water

resource concern



### • Surface water

quality impacts

• Shallow groundwater

quality impacts



### • Long

- term soil

damage from salinity

• Transportation

–

100,000 bbl = 770 trucks 

## BOTTOM LINE:

• Huge unconventional gas

resources are driving

development; and

water solutions are key

• Water quality concerns leading to

more treatment and reuse



### • Solutions can be simple to very

complex

– Reduce, Reuse, Recycle

are key goals

9

# Design Basis

Critical First Step

• Feed Water Volume



## • Feed Water Quality

• Treated Effluent Requirements

• Site Specific



## Considerations

10

# Flowback / Produced Water Treatment Solutions

• Treatment for Reuse Without TDS Removal



## • Treat for Reuse / Discharge with TDS Removal

1112



# TREATMENT FOR REUSE



# WITHOUT TDS REMOVAL

# Range of Applicability vs. Cost

RO Evaporation Crystallization

3,000 40,000 260,000 1,000,000

Total Dissolved Solids ( mg/L TDS) $ Costs per Barrel

750 

### Treatment for Reuse TDS Removal

No TDS Removal

13

# Example Feed Water Quality

• Water May Also Contain:

– Polymers

– Other Organics

– Radium



### – Other Inorganics

(e.g., boron)

14 Parameter Feed Water

pH 6.09

Bicarbonate 144

Calcium 11,595

Magnesium 690

Sodium 33,250

Iron ( diss ) 76

Barium 2,775

Strontium 3,633

Chloride 81,000

TSS 295

TDS 132,265

# Example Treatment Requirements

• pH: 6.5 to 7.5



## • Iron: < 10 mg/L

• TSS: < 50 mg/L

• Bacteria: None



## • Treatment Residuals:

Non

- hazardous

• Mobile system required



## (5,000 to 10,000 BWPD)

15

# Keys Design Considerations

• Water Chemistry

– Presence of organics, oxygen, and

nutrients

will result in bacteria growth!

– Precipitation of barium sulfate



### will tend to adsorb radium, which may

cause the sludge to become hazardous



## • Treatment Selection

– Efficient solids / liquid separate

required (small footprint)

– Sludge management

– Chemical consumption / dosing

16 Pretreatment Clarifier Chemicals

Waste Sludge Produced

Water Reuse

# Treatment Technology Options

Technology Bact. CH3OH O/G DRO GRO TA HCO3

- TH Ca Mg Fe Ba St SO4 Cl TDS TSS Poly

mers

API Separators X

Dissolved Gas Flotation X X

Activated Carbon X X X X

Nut Shell Filters X

Organi

- Clay Adsorbants X

Chemical Oxidation X X X

UV Disinfection X

Biological Processes X X X

Air Stripper X X X

Chemical Precipitation X X X X X X X

Lime/Soda Softening X X X X X X X

Clariifers X

Settling Ponds X

Ion Exchange X X X X X X X X X

Multi

- Media Filtration X

Membrane Filtration X X

Greensand Filters X X

Cartridge Filters X

Reverse Osmosis X X X X X X X X

Evaporation X X X X X X X X X

Steam Stipping X X X

Acidification X X

17

# Example of Reuse Treatment Solution

Without TDS Removal

18 Sand Filter:

TSS Removal Frac

Flowback

Water Treated

Water

Chlorine

Dioxide Air Oil

Byproduct

Chemical

Oxidation Free Oil and

TSS Removal TSS and O/G

Polish Sludge for

dewatering/

disposal Chlorine

Dioxide

Disinfection

# Step 1. Chlorine Dioxide Oxidation

• Chlorine dioxide is strong



## oxidant that provides selective

chemical oxidation

• Breaks oil / grease emulsions

• Destroys friction reducers and

other chemical additives

• Kills Bacteria

• Oxidizes reduced compounds,



## such as Fe, Mn , Sulfide, etc.

• More efficient than bleach

–

does not react with ammonia

and many other organics

19 Ref: Sabre Technologies

# Step 2. Dissolved Air Flotation

• Fine bubble diffusion floats oil / grease and TSS to top



## • Skimmer potentially recovers saleable oil

• Covered designs also available for VOC emission control

• Skid

- mounted design

20 Ref: Pan America

Environmental Website NOTE: Dissolved Gas

or Induced Gas Flotation

may also be considered

# Step 3. Multi

- Media Sand Filtration

• Conventional sand filter



## removes TSS before reuse

• Acid or carbon dioxide addition

ahead of filter to reduce pH and

eliminate calcium carbonate scaling

• Periodically backwashed

with filtered water. BW

returned to front of system.

• Chlorine dioxide disinfection

of final product water

21

# Summary of Reuse Treatment

Without TDS Removal

• Simplest and least expensive form of treatment



## • Multiple technology and design options available

• Reduces fresh water makeup

requirements and off

- site disposal costs



## • Applicable only if drilling operations that

need frac flowback water are on

- going

• Bench and pilot

- scale testing recommended to



## select best treatment options and minimize cost

2223



# TREATMENT OPTIONS



# FOR TDS REMOVAL

# Viable TDS Removal Alternatives

• Membrane Treatment



## • Evaporation

• Crystallization

24

# Range of Applicability vs. Cost

RO Evaporation Crystallization

3,000 40,000 260,000 1,000,000

Total Dissolved Solids ( mg/L TDS) $ Costs per Barrel

750 

### Treatment for Reuse

25

# Reverse Osmosis

• Membrane separation technology that



## removes dissolved solids (TDS) from water

• Membrane is semi

- impermeable

- allowing only

water to pass; 99%+ of all ionized species are rejected

• Non

- selective

treatment process

• Degree of all ion

rejection is dictated

by size and charge

• NF is a loose RO membane

26

# Reverse Osmosis (continued)

• Maximum concentrate TDS is approx. 80,000 mg/L



## • Energy costs are 1/10 th 

## to 1/15 th



## the cost of mechanical evaporation

• Skid

- mounted, compact design



## • Operating pressures

up to 1200 psig

• Multiple membranes and



## manufacturers available

27

# Historical Problems with RO

Treatment for Produced Water

• Limited success due to inadequate pretreatment,



## resulting in fouling and scaling from:

– Calcium Hardness

– Iron

– Barium and Strontium

– Silica

– Microbiological Growth

– Organics

– Silt and Suspended Solids

28

# Scale Forming Salts

Salt 

### Saturation

Concentration (mg/L)

Calcium Carbonate (CaCO

3 ) 8

Calcium Fluoride (CaF

2 ) 29

Calcium Orthophosphate (CaHPO

4 ) 68

Calcium Sulfate (CaSO

4 ) 680

Strontium Sulfate (SrSO

4 ) 146

Barium Sulfate (BaSO

4 ) 3

Silica, amorphous (SiO

2 ) 120

# Key to Success: Efficient Pretreatment

• Pretreatment Steps:

– Organics removal (oil / grease, polymers, etc.)

– Efficient management of hardness and metals

– Particulate removal



### – Bacteria control

Result: Better pretreatment leads to less membrane fouling,

higher water recovery and a lower cost of brine disposal

30

# Example Treatment Solution for TDS Removal

31 RO:

TDS Removal Treated

Water

Anti

scalant Cartridge

Filtration:

TSS Polish Sulfite Brine

Conc. Sand Filter:

TSS Removal Frac

Flowback

Water

Chlorine

Dioxide Air Oil

Byproduct

Sludge for

dewatering/

disposal Chlorine

Dioxide

# Range of Applicability vs. Cost

RO Evaporation Crystallization

3,000 40,000 260,000 1,000,000

Total Dissolved Solids ( mg/L TDS) $ Costs per Barrel

750 

### Treatment for Reuse

32

# Evaporation

• Ideal TDS Range of Feed Water

is 40,000 to 120,000 mg/L

• Produces high quality distillate

and liquid brine concentrate

• Brine concentrate requires further

treatment or disposal (max TDS

concentration is approx. 260,000 mg/L)

• Evaporation systems more

energy intensive than RO

• Most evaporation systems

cannot handle any solids

33

# Types of Evaporation Systems

• Forced Circulation



## • Falling Film

• Rising Film

• Agitated Thin Film



## • Plate and Frame

34

# Selection Considerations

• Chemical Composition of Feed Stream



## • Scaling / Fouling Potential

• Foaming Potential

• Materials of Construction

– Chloride concentrations

– Temperature

35

# Economization

• Multiple Effects

– Vapor From Each Effect is used in the Next / Previous

Effect Depending on Set

- up to Reduce Steam Use



## • Vacuum

– Reduces Boiling Point

– Maximizes Efficiency When Used in Concert With Multiple Effects



## • Mechanical Vapor Recompression

– Recompresses the Vapor to Reduce Steam Use

– Usually Uses Just One Effect

36

# MVR Evaporator

Most Economical for this Application

37

# Range of Applicability vs. Cost

RO Evaporation Crystallization

3,000 40,000 260,000 1,000,000

Total Dissolved Solids ( mg/L TDS) $ Costs per Barrel

750 

### Treatment for Reuse

38

# Crystallizer

• Complex system capable of



## producing purified salt products

from impure solutions

• Multiple Types of

Crystallizers available

• Principals of Crystallization include:

– Evaporation to form

supersaturated solution

– Nucleation and

growth of salt crystals

– Harvesting, washing



### and drying of salt crystals

39Parameter Feed Water

pH 6.09

Bicarbonate 144

Calcium 11,595

Magnesium 690

Sodium 33,250

Iron ( diss ) 76

Barium 2,775

Strontium 3,633

Chloride 81,000

TSS 295

TDS 132,265 

# Application of a Crystallizer in the Marcellus

• Crystallizer Products:

– Calcium Chloride Liquid

– Sodium Chloride Dry Salt

– Distilled Water

40

# Crystallizer Block Flow Diagram

41 Pretreatment Feed

Water Evaporator Crystallizer

Chemicals

Waste

Sludge Centrifuge Reuse/Discharge

Drilling Fluid or

Road Deicing

Road Salt Distilled Water

Calcium Chloride

Liquid (28

- 40%)

Sodium Chloride

Dry Salt (99+%)

Liquid Waste

Purge

# Key Considerations

• Proper Design



## • Feed Water Management

• Economics

– Byproduct Chemical Sales (ASTM specifications)

42

# TDS Treatment Options Summary

• RO membranes have found little use in the Marcellus



## • Evaporation technology using Mechanical Vapor

Recompression most common form of TDS Treatment

• Crystallization technology is complex but can be cost



## effective with sale of commodity chemical byproducts

• All technologies generally produce some

amount of waste brine that requires disposal

43

# Questions and Answers

Robert J. Kimball, P.E., BCEE

Technical Director Produced



### Water Treatment

50 West 14 th 

### Street

Helena, MT 59601

406

- 441

- 1441 (office)

Kimballrj @cdmsmith.com (email)

44