July 2013 I www.epa.gov/hfstudy

Summary of the Technical Workshop on

Wastewater Treatment and Related Modeling

April 18, 2013
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

ii

Disclaimer 

This report was prepared by EPA with assistance from Eastern Research Group, Inc., an EPA 

contractor, as a general record of discussions during the April 18, 2013, technical workshop on 

wastewater treatment and related modeling. The workshop was held to inform EPA’s Study of 

the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources. The report 

summarizes the presentations and facilitated discussions on the workshop topics and is not 

intended to reflect a complete record of all discussions. All statements and opinions expressed 

represent individual views of the invited participants; there was no attempt to reach consensus on 

any of the technical issues being discussed. Except as noted, none of the statements in the report 

represent analyses or positions of EPA.

Mention of trade names or commercial products does not constitute endorsement or 

recommendations for use.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

iii

Table of Contents

Meeting Agenda ............................................................................................................................ 1

List of Meeting Participants......................................................................................................... 4

Introduction................................................................................................................................... 6

Summary of Presentations for Session 1: Hydraulic Fracturing Wastewater Treatment..... 7

Summary of Discussions Following Session 1: Hydraulic Fracturing Wastewater 

Treatment .................................................................................................................................... 10

Summary of Presentations for Session 2: Current and Future Trends in Hydraulic 

Fracturing Wastewater Management....................................................................................... 12

Summary of Discussions Following Session 2: Current and Future Trends in Hydraulic 

Fracturing Wastewater Management....................................................................................... 14

Concluding Remarks.................................................................................................................. 16

Appendix A. Extended Abstracts from Session 1: Hydraulic Fracturing Wastewater 

Treatment .................................................................................................................................. A-1

Overview of EPA’s Hydraulic Fracturing Wastewater Research .......................................... A-2

Achieving Zero Discharge of Water from Non-Conventional Oil & Gas Hydrofracturing 

Activities.............................................................................................................................. A-11

From Pilot Study to Daily Processing Warren, Ohio’s Documentary to Hydraulic Fracturing 

Wastewater Treatment ......................................................................................................... A-21

Reducing Fresh Water Use in Upstream Oil and Gas Hydraulic Fracturing ....................... A-37

Treatment for the Beneficial Reuse of Produced Water and Hydraulic Fracturing Flowback 

Water.................................................................................................................................... A-44

Marcellus Wastewater Treatment: Case Study .................................................................... A-56

Appendix B. Extended Abstracts from Session 2: Current and Future Trends in Hydraulic 

Fracturing Wastewater Management..................................................................................... B-1

Successful Oilfield Water Management: Five Unique Case Studies..................................... B-2

Produced Water Management in the Marcellus................................................................... B-13

Mid-Continent Water Management for Stimulation Operations ......................................... B-14

Utilizing Models Developed for Water Management and Risk during Carbon Storage to 

Improve Water Management during Unconventional Gas Exploration and Production ..... B-19
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

iv

Appendix C. Poster Abstracts................................................................................................. C-1

Sustainable Water Treatment, Recycling & Disposal Practices in the Marcellus Shale Basin

................................................................................................................................................ C-2

Feasibility of In Situ Sequesteration of Toxic Metals in Flowback Water from Hydraulic 

Fracturing. ............................................................................................................................ C-10

Wastewater Made Clear with Green Technology ................................................................ C-15

Oil and Gas Water Purification using Switchable Polarity Solvent Forward Osmosis 

(SPS-FO).............................................................................................................................. C-19
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

1

Meeting Agenda

Technical Workshop on Wastewater Treatment and Related Modeling

April 18, 2013

U.S. EPA Research Triangle Park Campus

“C” Building Auditorium

Research Triangle Park, NC

8:00 am Registration/Check-in

8:30 am Welcome and Introductions...............................................................................Ramona Trovato, US EPA 

8:40 am Opening Remarks.......................................................................Glenn Paulson, Science Advisor, US EPA

8:45 am Purpose of Workshop ................................................................................................Workshop Co-Chairs:

Cynthia Sonich-Mullin, US EPA

Thomas Starosta, PA DEP

Session 1: Hydraulic Fracturing Wastewater Treatment

8:55 am Panel Presentations:

1. Overview of Hydraulic Fracturing Wastewater Research ...................... Cynthia Sonich-Mullin and

Christopher Impellitteri, US EPA

2. Zero Water Discharge: Management for Hydrofracturing Activities............................Carl Adams, 

ENVIRON International Corporation

3. From Pilot Study to Daily Processing: Warren, Ohio's Documentary to Hydraulic Fracturing 

Water Treatment ..................................................................... Thomas Angelo, City of Warren, Ohio, 

Water Pollution Control Department

4. Reducing Fresh Water Use in Upstream Oil & Gas Hydraulic Fracturing ........... Michael Dunkel, 

Pioneer Natural Resources

5. Treatment for Beneficial Use of Produced Water and 

Hydraulic Fracturing Flowback Water........................ David Stewart, Energy Water Solutions, LLC

6. Marcellus Wastewater Treatment – Case Study ..................... Daniel Ertel, Eureka Resources, LLC

Questions of Clarification

Break (10 minutes)

Facilitated discussion among workshop participants focusing on key questions: 

 What are some modern and potential future trends in reuse, recycling, zero-liquid discharge and 

commercial transport? 

 How to manage, dispose and characterize residuals of hydraulic fracturing? 

 What are the consequences of disposal via landfills or beneficial reuse?
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

2

11:45 am Summary of Session 1................................................................................................Workshop Co-Chairs:

Cynthia Sonich-Mullin, US EPA

Thomas Starosta, PA DEP

12:00 pm Lunch (on your own) and Poster Session

Session 2: Current and Future Trends in Hydraulic Fracturing Wastewater Management

 1:30 pm Panel Presentations

1. Successful Oilfield Water Management: Five Unique Case Studies..................... Brent Halldorson,

Fountain Quail Water Management

2. Produced Water Management in the Marcellus....................................................... Meagan Mauter,

Carnegie Mellon University

3. Mid-Continent Water Management for Stimulation Operations ........................... D. Steven Tipton, 

Newfield Exploration Company

4. Utilizing Models Developed for Water Management and Risk during Carbon Storage to 

Improve Water Management during Unconventional 

Gas Exploration and Production....................................................................... Enid J. (Jeri) Sullivan,

Los Alamos National Laboratory

Questions of Clarification

Facilitated discussion among workshop participants focusing on key questions: 

 What are the contributions of selected contaminants from hydraulic fracturing relative to other 

potential sources of contamination? 

 What are some applications of surface and subsurface modeling?

 How much flowback or produced water is created, and what happens to it? 

 How do we currently monitor wastewater disposition? 

 How do the projected volumes of wastewater compare to wastewater management capacity, including 

underground injection wells and treatment systems? 

 What are the regional differences in wastewater quantity and quality and potential impacts on 

drinking water sources? 

3:45 pm Summary of Session 2........................................................................................... ... Workshop Co-Chairs:

Cynthia Sonich-Mullin, US EPA

Thomas Starosta, PA DEP

3:55 pm Closing Remarks............................................................................................... Ramona Trovato, US EPA

4:00 pm Adjourn
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

3

Poster Session

Sustainable Water Treatment, Recycling and Disposal Practices in the Marcellus Shale Basin

Matthew Bruff, Altela, Inc.

Feasibility of In Situ Sequestration of Toxic Metals in Flowback Water from Hydraulic Fracturing

Andrew Stack, Oak Ridge National Laboratory

Use of Switchable Solvents as Forward Osmosis Draw Solutes

Aaron Wilson, Idaho National Laboratory

Wastewater Made Clear with Green Technology

Patricia Werner-Els, Advanced Waste & Water Technology
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

4

List of Meeting Participants

Carl Adams*

ENVIRON International Corporation

Thomas Angelo*

Water Pollution Control Department 

(Warren, OH)

John Bailey

Arkansas Department of Environmental 

Quality

William Bates

US EPA Region 5

Lisa Biddle

US EPA Office of Water, Office of Science 

and Technology

Matthew Bruff

Altela, Inc.

Lawrence Cenegy

Hess Corporation

Thomas Chambers

Southwestern Energy Company

Nancy Coleman

Environmental Consultants

George DeVaull

Shell Global Solutions US, Inc.

Michael Dunkel*

Pioneer Natural Resources

Daniel Ertel*

Eureka Resources, LLC

Peter Fyfe

Southwestern Energy Company

Ganesh Ghurye

ExxonMobil Upstream Research Company

Marc Glass

Downstream Strategies, LLC

Brent Halldorson*

Fountain Quail Water Management

Christopher Harto

Argonne National Laboratory

Thomas He

West Virginia University

Jason Heath

Ohio River Valley Water Sanitation 

Commission

Chris Impellitteri*

US EPA ORD/National Risk Management 

Research Laboratory

Thomas Kropatsch

Wyoming Oil and Gas Conservation 

Commission

Dennis Lamb

Wyoming Department of Environmental 

Quality

John Lucey

Heckmann Corporation

Allison MacKay

University of Connecticut, Storrs, CT

Lisa Matthews

US EPA Office of Research and 

Development

Earl Mattson

Idaho National Laboratory

Meagan Mauter*

Carnegie Mellon University
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

5

Rick McCurdy

Chesapeake Energy Corporation

Kent McManus

Eureka Resources, LLC

Pete Miller

Range Resources-Appalachia, LLC

Jennifer Orme-Zavaleta

US EPA ORD/National Exposure Research 

Laboratory

Glenn Paulson

US EPA, Science Advisor

Yves Pollart

Rettew Flowback, Inc.

Vikram Rao

Research Triangle Energy Consortium

Emily Reader

California Department of Conservation

Susan Sharkey

US EPA Office of Research and 

Development

Cynthia Sonich-Mullin* (co-chair)

US EPA ORD/National Risk Management 

Research Laboratory

Andrew Stack

Oak Ridge National Laboratory

Thomas Starosta (co-chair)

Pennsylvania Department of Environmental 

Protection

David Stewart*

Energy Water Solutions, LLC

Enid Jeri Sullivan*

Los Alamos National Laboratory

D. Steven Tipton*

Newfield Exploration Mid-Continent, Inc.

Ramona Trovato

US EPA Office of Research and 

Development

Denise Tuck

Halliburton Energy Services, Inc.

Jim Weaver

US EPA ORD/National Risk Management 

Research Laboratory

Patricia Werner-Els

Advanced Waste and Water Technology

Drue Ann Whittecar

National Oilwell Varco

Aaron Wilson

Idaho National Laboratory

Lloyd Wilson

New York State Department of Health

Scott Wilson

US EPA Office of Water, Office of 

Wastewater Management

Gary Wolinsky

Chevron Energy Technology Company

* Presenter
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

6

Introduction

At the request of Congress, the U.S. Environmental Protection Agency (EPA) is conducting a 

study to better understand the potential impacts of hydraulic fracturing on drinking water 

resources. The scope of the research includes the full cycle of water associated with hydraulic 

fracturing activities. In the study, each stage of the water cycle is associated with a primary 

research question:

Water acquisition: What are the possible impacts of large volume water withdrawals 

from ground and surface waters on drinking water resources?

Chemical mixing: What are the possible impacts of hydraulic fracturing fluid surface 

spills on or near well pads on drinking water resources?

Well injection: What are the possible impacts of the injection and fracturing process on 

drinking water resources?

Flowback and produced water: What are the possible impacts of surface spills on or 

near well pads of flowback and produced water on drinking water resources?

Wastewater treatment and waste disposal: What are the possible impacts of 

inadequate treatment of hydraulic fracturing wastewaters on drinking water resources?

In 2013, EPA hosted a series of five technical workshops related to its Study of the Potential 

Impacts of Hydraulic Fracturing on Drinking Water Resources. The workshops included

Analytical Chemical Methods (February 25, 2013), Well Construction/Operation and Subsurface 

Modeling (April 16–17, 2013), Wastewater Treatment and Related Modeling (April 18, 2013), 

Water Acquisition Modeling (June 4, 2013) and Hydraulic Fracturing Case Studies (July 30, 

2013). The workshops were intended to inform EPA on subjects integral to enhancing the overall 

hydraulic fracturing study, increasing collaborative opportunities and identifying additional 

possible future research areas. Each workshop addressed subject matter directly related to the 

primary research questions.

For each workshop, EPA invited experts with significant relevant and current technical 

experience. Each workshop consisted of invited presentations followed by facilitated discussion 

among all invited experts. Participants were chosen with the goal of maintaining balanced 

viewpoints from a diverse set of stakeholder groups, including industry; nongovernmental 

organizations; other federal, state and local governments; tribes; and the academic community.

The Wastewater Treatment and Related Modeling workshop was co-chaired by Cynthia SonichMullin (EPA) and Thomas Starosta (Pennsylvania Department of Environmental Protection 

[PADEP]). A morning session addressed Hydraulic Fracturing Wastewater Treatment, while the 

afternoon session focused on Current and Future Trends in Hydraulic Fracturing Wastewater 

Management. In addition, several experts shared technical knowledge during a poster session 

(Appendix C).
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

7

Summary of Presentations for Session 1:

Hydraulic Fracturing Wastewater Treatment

Susan Hazen, Hazen Consulting and Support Services, opened the workshop. She noted that 

EPA was looking for individual participants’ frank input and opinion and was not trying to reach 

consensus on the topics; the workshop was not held under the rules of the Federal Advisory 

Committee Act (FACA). Dr. Glenn Paulson, Science Advisor to the EPA Administrator, and 

Ramona Trovato, Associate Assistant Administrator of EPA’s Office of Research and 

Development, welcomed the participants and thanked them for contributing their knowledge and 

experience to help answer the wastewater management research questions in EPA’s drinking 

water study. Workshop Co-Chairs Cynthia Sonich-Mullin, Director, EPA’s National Risk 

Management Research Laboratory (NRMRL), and Thomas Starosta (PADEP) explained that 

the purpose of the workshop was to obtain input from experts and understand the current state of 

technology in a rapidly changing industry. They added that the workshops are designed to foster 

collaboration, and that EPA intends for the published drinking water study to reflect the input 

from all the technical workshops. 

Ms. Sonich-Mullin and Dr. Christopher Impellitteri, EPA, presented an overview of the 

hydraulic fracturing wastewater research in EPA’s drinking water study. Ms. Sonich-Mullin 

noted that the overall goals for EPA’s study are to assess whether hydraulic fracturing may 

impact drinking water resources, and to identify any driving factors that may influence the 

severity and frequency of any potential impacts. For the water treatment and waste disposal stage 

of the hydraulic fracturing water cycle, EPA’s secondary research questions are:

What are the common treatment and disposal methods for hydraulic fracturing 

wastewater and where are these methods practiced?

How effective are conventional publicly owned treatment works (POTWs) and 

commercial treatment systems in removing organic and inorganic contaminants of 

concern in hydraulic fracturing wastewater? 

What are the potential impacts from surface water disposal of treated hydraulic fracturing 

wastewater in drinking water treatment facilities?

Dr. Impellitteri described the research projects associated with these research questions. These 

projects include literature review, well file review, FracFocus analysis, wastewater treatability 

studies, surface water modeling, source apportionment studies and brominated disinfection 

byproduct precursor studies. He noted that water quality issues vary greatly from state to state, 

play to play and even well to well. He also said that the most challenging aspects of this research 

are the rapid changes in how hydraulic fracturing wastewaters are managed and treated.

Dr. Carl Adams, ENVIRON International Corporation, discussed achieving zero discharge of 

water from unconventional oil and gas hydraulic fracturing activities by recycling 100 percent of 

the combined flowback and produced waters for subsequent hydraulic fracturing activities. He 

described a project in which wastewater is managed using traditional industrial wastewater 

management protocols. He stated that, in his opinion, high concentrations of total dissolved 

solids (TDS) are not a treatment problem if biological treatment was considered as an option, 

citing the example of wastewater with 18 percent salt being treated in the North Sea and in 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

8

several Middle Eastern industrial situations. He said that the recycling issue could be managed 

with chemistry and conventional technology solutions, such as filtration. More expensive and 

complex technologies, such as membranes, chemical oxidation and evaporation, are not 

warranted. He stated his view that the economics of recycling hydraulic fracturing wastewaters 

depend on the possible complications from the residual chemical content of the recycled 

wastewaters. 

Dr. Adams stated that, based on data characterization for both flow and quality, a cost-effective 

water management approach has been developed to recycle flowback and produced water—

blended with fresh water in appropriate quantities for TDS control—for use in subsequent 

hydraulic fracturing well activity. Dr. Adams said that zero discharge might be obtained by 

operating a staged and/or parallel pretreatment to remove constituents from separate or combined 

wastewaters and making chemical adjustments to maintain constituents, such as naturally 

occurring radioactive material (NORM) and heavy metals in solution. Also, pretreatment would 

be designed to remove only selected compounds that may interfere with subsequent recycling, 

while avoiding precipitation of large quantities of excess sludge for disposal.

Dr. Adams’ company performed comprehensive technology evaluations and undertook a 

selection process to develop a reliable process train. The company also developed an economic 

model to compare costs with traditional approaches. Dr. Adams stated that 100-percent recycling 

of hydraulic fracturing wastewater may be achievable if the process train is confirmed in benchscale and field-scale trials. Potential benefits include lower operating costs; reduced presence of 

sulfide; reduced trucking; an operator-friendly process; and a more reliable, predictable and 

environmentally sensitive program.

Thomas Angelo, City of Warren, Ohio, Water Pollution Control Department, described a pilot 

study involving treatment of hydraulic fracturing wastewater in Warren, Ohio. In 2009, Warren 

began a pilot study to identify the amount of brine that its wastewater treatment plant (WWTP) 

could receive without causing WWTP or water quality issues. The pilot study determined that if 

a consistent amount of brine water were discharged over an extended period of time, there would 

be no adverse effects on the WWTP or adverse changes to the quality of the discharges of treated 

water based on limits in the existing discharge permit. Mr. Angelo described the model for daily 

processing of flowback brine water, including requirements for pretreatment, limits on the 

volume of brine water treated daily, limits on TDS discharged into the WWTP and testing for 

pollutants of concern (e.g., heavy metals, radiation, volatile organic compounds). Mr. Angelo 

stated his view that 21⁄2 years of operational data using this model have shown that it is a safe and 

viable option that complements other disposal options.

Michael Dunkel, Pioneer Natural Resources, described an initiative to reduce fresh-water use in 

upstream oil and gas hydraulic fracturing. He described a study of three shale plays in Texas 

aimed at determining the water quality needed for hydraulic fracturing. Recommendations varied 

in the three cases but included removing total suspended solids (TSS) and blending with 50 to 80 

percent fresh water to reduce the impact of specific minerals on hydraulic fracturing design. Mr. 

Dunkel presented some information about water treatment technologies and pilot tests, indicating 

that different processes give different results. He described the logistics, economics and 

environmental aspects of produced water transportation and storage. Using brackish water, he 

stated, can be more expensive than using ground water but is less costly than recycling. 

Additionally, brackish water is more plentiful in some areas of Texas than fresh ground water. 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

9

Mr. Dunkel also discussed preventing evaporation from storage using pond covers that float on 

the surface, and indicated that in hot, dry climates, this can be more economical than recycling 

and could be one component in the effort to conserve fresh water. 

Dr. David Stewart, Energy Water Solutions, LLC, discussed treatment of produced and 

flowback water for beneficial reuse. Water reuse and recycling, he stated, will become an 

increasingly significant issue for developing oil and gas shale plays in the United States, and this 

country could potentially become a world leader in technologies for recycling and reuse. Dr. 

Stewart stated that, while water use for hydraulic fracturing is a small percentage of overall water 

use, it represents a large amount of water consumed and is especially significant in areas dealing 

with drought conditions. He discussed constituents of concern for water reuse and the need to 

develop criteria for reuse. He stated that chemical control of the brine stream, which can contain 

50,000 to 300,000 mg/L TDS, is the most difficult issue in recycling/reuse. According to Dr. 

Stewart, if the scale-forming chemicals can be removed, this type of water potentially could be 

used for drilling operations or for manufacturing hydrochloric acid or bleach solution and 

sodium hydroxide. He also indicated that treatment technologies that fit the final reuse and 

recycling criteria (different for each field) will need to be deployed economically, and that 

byproduct capture (e.g., lithium) can be a cost-effective aspect of recycling and reuse.

Dan Ertel, Eureka Resources, LLC, presented a case study on centralized treatment of Marcellus 

wastewater to maximize recycling and protect water quality. He described an approach for 

centralized treatment of hydraulic fracturing wastewaters that has the flexibility to provide the 

level of the treatment needed to promote reuse of treated water. He indicated that this method

can provide the following for potential reuse: pretreated water, distilled water, concentrated brine 

purge, salt, calcium chloride brine and treated water meeting Pennsylvania dewasting standards 

(i.e., water that is no longer considered an industrial waste product and may be stored in less 

stringently regulated impoundments). Mr. Ertel described the unit processes in pretreatment, 

secondary treatment (distillation and crystallization) and tertiary treatment (biological/reverse 

osmosis), saying that co-product reuse studies are underway, focusing on beneficial reuse of dry 

sodium chloride and liquid calcium chloride.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-10

Summary of Discussions Following Session 1:

Hydraulic Fracturing Wastewater Treatment

Following some clarifying questions, participants were asked to consider the following questions 

during the discussion: 

What are some modern and potential future trends in reuse, recycling, zero-liquid 

discharge and commercial transport? 

How can the residuals of hydraulic fracturing be managed, disposed of and 

characterized? 

What are the consequences of disposal via landfills or beneficial reuse?

Key themes from Session 1 discussion:

Potential drinking water impacts. A participant asked about the relationship between the 

wastewater treatment issue and potential drinking water impacts, stating his view that the 

brackish water being discussed is not a drinking water resource and never has been. An EPA 

participant noted that water used initially is sometimes from drinking water sources, that 

discharge of wastewater to surface waters could potentially impact drinking water sources, and 

that increased reuse and recycling will probably lessen the impacts on drinking water and 

drinking water sources because it will likely result in less discharge.

Reuse and Recycling. Several participants stated that there is a clear industry trend toward reuse 

and recycling of produced and flowback water. One participant noted that five years ago, 

industry believed that only fresh water could be used for hydraulic fracturing fluid, but the 

quality of water that industry is using is changing rapidly due to developments in fracturing 

water formulation, improvements in wastewater treatment/reuse technologies and an increased 

need for low-cost water. Several participants noted issues that affect the need or ability to reuse 

or recycle, including wastewater storage, transport and economics (e.g., gas prices). A participant 

also noted that water availability is a huge issue in the West, necessitating water reuse. While 

one participant described close to 100-percent reuse in some locations, others stated that 

economic and technology barriers still exist, and it will take several years to determine which 

technologies are viable. A participant suggested consulting with well owners/operators about

their experience to understand the varying perspectives on limits to reuse. Several participants 

noted that there is no single solution to water management; it needs to be considered on a sitespecific basis. A participant said that in some areas, hydraulic fracturing may have amplified 

water management issues, but it did not create them. A participant suggested an industrial 

process approach to increasing reuse and decreasing use of fresh water. 

Chemical issues for water reuse. Several participants discussed the need to look at solubility 

and scale-forming criteria. One participant said that a Texas A&M study and U.S. Geological 

Survey (USGS) program on scale formation could be useful. Another participant noted that 

boron can be a problem because it crosslinks the gel fractures; he added that industry is 

investigating boron removal, which currently is expensive. One participant recommended future 

research and development to look at the buildup (accumulation) of boron, calcium and 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-11

magnesium. A participant also stated that an industry consortium is looking at which chemicals 

are toxic and at what concentrations, and whether there are “green” alternatives. 

Transport and mobile treatment. Some participants discussed transport costs associated with 

recycling, which they said can be 25 to 75 percent of the total cost of handling water. Onsite 

treatment, it was noted, may be a solution for reducing these costs, depending on the location. A 

participant stated that multiple pads in a concentrated area facilitate centralized treatment, while 

in areas where drilling operations are more sparse, mobile and/or onsite treatment may be 

preferable.

Sharing water. A participant asked whether operators could collaborate and share water to help 

solve storage and downtime issues. Someone stated that there might be an opportunity to work 

with a wastewater treatment plant as a “brokerage” (e.g., there have been legal and liability 

questions, with operators prohibited from transporting to other operators or sites in some areas). 

A participant noted that Texas has changed its rules to allow operators to share water, and that 

produced water is starting to be viewed as an asset. Another participant stated that, in the future,

there will be networked systems with shared pipelines and storage.

Beneficial reuse of residuals. Some participants noted an industry trend toward more beneficial 

use of produced and flowback water and treatment residuals (e.g., sodium chloride, calcium 

chloride, recovered metals). Several participants said that the potential health and environmental 

impacts of beneficial use must be carefully considered, and that meeting the regulations may not 

be sufficient. One participant stated that waste streams from hydraulic fracturing are not yet fully 

characterized. Another participant stated that selective removal of constituents is problematic 

because of the hazardous sludge it might create. He stated that it might be better to keep 

chemicals in solution and put them back down the hole than to create more hazardous 

wastewaters and residual solids. 

Several participants raised issues regarding reuse of calcium brine (e.g., levels of bromide, 

volatile organic chemicals, barium and radioactive materials). A participant noted that the trade 

secret aspect of hydraulic fracturing fluids can make beneficial use difficult from the regulator’s 

perspective. A participant recommended that more research and development be focused on 

ways to turn wastes into assets.

Disposal via landfills. Several participants discussed issues with residuals going to municipal 

solid waste facilities. One participant described a practice of adding sawdust to mud for landfill 

disposal, which does not prevent leaching. It was noted that there may be a trend toward using 

landfills that take industrial wastes, which are different from subclass C (“hazardous waste”) 

landfills. One participant described a wastewater treatment plant that has set up a partnership to 

reuse methane and drill cuttings, and cautioned about sending residuals to power generation

facilities because of the potential impacts of inorganics on waste-to-energy processes. A 

participant noted a need to develop best practices for treating and managing the waste streams.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-12

Summary of Presentations for Session 2:

Current and Future Trends in Hydraulic Fracturing Wastewater 

Management

Brent Halldorson, Fountain Quail Water Management, presented five case studies highlighting 

five different scenarios for successful oilfield water management. Two of the examples involved 

using fresh water, two involved reusing saltwater and one involved using brackish water. 

Selecting salt water or fresh water is the initial, fundamental choice that must be made for water 

management. Using fresh water costs more but involves lower risks during storage and transport; 

using salt water is less expensive but is logistically more difficult. After the initial water 

selection is made, the next step involves setting simple, achievable goals and selecting a 

treatment partner or technology with a proven track record. New trends include using pit covers 

to prevent evaporation, combining recycling and disposal, using more brackish and salt water, 

having commonsense discussions among parties involved in water management and offering 

incentives for recycling. Mr. Halldorson emphasized the importance of sharing both positive and 

negative results and experiences to improve water management.

Dr. Meagan Mauter, Carnegie Mellon University, discussed research to quantify the impacts of 

produced water management in the Marcellus. She said that water transport generates significant 

regional impacts, some highly visible. Initial results from analysis of PADEP data show 

significant variations in waste management practices among companies, with much of the 

variation due to the waste disposal methods selected, the level of company experience in the 

Marcellus and the drilling practices implemented. Dr. Mauter stated that a key intervention 

affecting produced water management is “clustering.” Companies that drill their wells in clusters 

reuse a larger percentage of waste and reduce waste transport distances.

Steven Tipton, Newfield Exploration Company, discussed water use and reclamation for the 

stimulation of the Granite Wash tight reservoirs and the shale oil reservoirs of the Cana 

Woodford Shale, both in the Anadarko Basin. These areas have evolved as drilling activity has 

increased and changed, and an infrastructure has been created to support completion operations 

and the need for water. Mr. Tipton presented an overview of the water sources, transport, 

storage, treatment and reuse, and disposal, and identified challenges to recycling. He indicated 

that in Granite Wash, more than 80 percent of water used is recycled and that the flowback and 

produced water has low chloride content. Water is transported to recycling pits through poly 

lines. Mr. Tipton said that there are plans to recycle produced water from Cana Woodford, 

transporting water to a recycling facility by truck. He noted that reusing produced water saves 

fresh water, is environmentally responsible and improves a company’s “social license.”

Dr. Enid Sullivan, Los Alamos National Laboratory, discussed using models developed for 

water management and risk during carbon storage to improve water management during 

unconventional gas exploration and production. Dr. Sullivan presented some results from 

applying the CO2PENS (Predicting Engineered Natural Systems) model to produced water (with 

the addition of transport costs and organic pretreatment capability). The results indicate that 

thermal treatment methods may be more cost effective than membrane methods in many cases. 

She also described using large-scale computational models to predict carbon storage contaminant 

fate and transport to evaluate hydraulic fracturing impacts on drinking water quality over large 

scales and timeframes. In addition, she discussed using large-scale computational models 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-13

(ASCEM and AMANZI) to predict environmental contaminant fate and the impacts of climate 

on water resources, as well as potentially using these models to evaluate hydraulic fracturing 

impacts on drinking water quality over large scales and timeframes. Dr. Sullivan indicated that 

industry data and feedback are needed to build these models properly.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-14

Summary of Discussions Following Session 2:

Current and Future Trends in Hydraulic Fracturing Wastewater 

Management

Following clarifying questions, participants were asked to consider the following questions 

during the discussion:

What are the contributions of selected contaminants from hydraulic fracturing relative to 

other potential sources of contamination? 

What are some applications of surface and subsurface modeling?

How much flowback or produced water is created, and what happens to it? 

How do we currently monitor wastewater disposition? 

How do the projected volumes of wastewater compare to wastewater management capacity, 

including underground injection wells and treatment systems? 

What are the regional differences in wastewater quantity and quality and the potential 

impacts on drinking water sources?

Key themes from Session 2 discussion:

Relative contributions of hydraulic fracturing contaminants versus other contaminants. A 

participant noted that determining relative source contributions can be difficult. One participant

recommended looking at load allocations. Another suggested reviewing watershed studies for 

sources such as runoff, mining, TDS and bromides from pharmaceuticals. A participant noted 

that an important source of bromides is scrubber discharge from coal-fired power plants. A 

participant discussed using potential markers of hydraulic fracturing impacts, such as 

radioisotopes (tritium), which are not found in produced water before reuse. A participant stated 

that chloride may be a useful marker for ground water but may be useless for surface waters,

where there are many other sources. A participant noted that for risk management, the total daily 

maximum load (TDML) is useful, but for forensics, there are many sources of the contaminants 

assessed at very low concentrations. One participant recommended a tiered approach (i.e., first

measuring simple parameters such as conductivity and turbidity, then following up with 

methane, barium, etc. if needed). Looking at a suite of chemicals (as opposed to looking at 

chemicals singly) was also suggested.

Modeling applications. One participant emphasized the importance of establishing the science 

basis when applying models (i.e., characterizing different sources of contaminants in the 

watershed). Applications for modeling discussed by participants included the impact of using 

brackish water on nearby freshwater aquifers, impacts from unlined construction and demolition 

debris (C&D) landfills and impacts from landfill leachate going to POTWs. Also mentioned was 

the potential application of agent-based economic models combined with system-based dynamic 

models to look at social and economic issues surrounding reuse decisions.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-15

Water volumes and disposition. A participant noted that the amount of flowback water varies 

across plays and geographic areas and also changes over the life of the well. Several participants 

asked about the desirability of having more flowback water; one participant stated that the 

productivity of the well is the driver for the amount of flowback water. A participant stated that 

industry has an efficient system, building additional disposal wells or treatment capacity when 

needed. 

Several participants discussed the issue of reporting and tracking the disposition of hydraulic 

fracturing wastewater, noting that reporting standards and the accessibility of data are very 

different among the states. A participant noted that in some states, operators are required to have 

the data but not necessarily to report them. Several participants recommended more consistent 

reporting; according to one participant, reporting on a regular basis could help prevent unsafe 

disposal practices. The practical aspects of tracking in a large, complex system were noted.

One participant stated that operators are very skilled at gathering data on wastewater volume and 

disposition, and that they track carefully because of costs. Another participant said that it would 

be better for industry and the environment if new operators could learn from other operators in a 

formation rather than only from their own experience. The importance of long-term water 

resource management plans and collaboration between industry and government to obtain 

needed data were discussed by several participants. 

Disposal via underground injection. A participant stated that disposal through treatment 

facilities is still at a fairly low volume in the Marcellus, and that the dominant pathway for final 

disposal of wastewaters produced (after reuse and recycle options are exhausted) is underground 

injection in Ohio. A participant expressed concern about the capacity of Ohio injection wells to

meet the ongoing demand for final disposal, should Ohio have cause to restrict this pathway, or if 

it reaches saturation for any reason.

Regional differences. A participant stated that the Utica and Marcellus formations are using 

much more water than in the West, and that the volumes per well and overall are increasing 

substantially. One participant also noted that slick water fracturing uses more water than gel 

fracturing by a factor of two or three. In formations like the Bakken, less water is used and less 

water is returned. A participant also stated that the northeast Marcellus wastewater has high TDS 

but low volume; Oklahoma has a wide variation in water quality across plays. 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-16

Concluding Remarks

Ms. Trovato and Dr. Glenn Paulson, EPA, thanked the participants for attending and sharing 

their knowledge and experience, noting that the workshop discussions highlighted the rapid 

changes in the industry, which are essential for EPA’s study to address. They reminded the 

participants that once the technical workshops are completed, the technical roundtables will be 

reconvened to further inform the drinking water study. They noted that this ongoing stakeholder 

engagement will help ensure that human health and the environment are protected while the 

nation receives the economic and energy security benefits that unconventional oil and gas 

extraction can provide. 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-1

Appendix A.

Extended Abstracts from Session 1:

Hydraulic Fracturing Wastewater Treatment
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-2

Overview of EPA’s Hydraulic Fracturing Wastewater Research

Cynthia Sonich-Mullin and Christopher Impellitteri

US EPA

Information presented in this abstract is part of the U.S. Environmental Protection Agency’s ongoing 

study and cannot be used to draw conclusions about potential impacts to drinking water resources from 

hydraulic fracturing. Any mention of trade names or commercial products does not constitute 

endorsement for use.

Introduction

Natural gas plays a key role in our nation’s clean energy future. The United States has vast 

reserves of natural gas that are commercially viable as a result of advances in horizontal drilling 

and hydraulic fracturing technologies, which enable greater access to gas in rock formations deep 

underground. These advances have spurred a significant increase in the production of both 

natural gas and oil across the country. Responsible development of America’s oil and gas 

resources offers important economic, environmental, and energy security benefits. However, as 

the use of hydraulic fracturing has increased, so have concerns about its potential human health 

and environmental impacts; especially for drinking water.

In response to public concern, the U.S. House of Representatives requested that the U.S. 

Environmental Protection Agency (EPA) conduct scientific research to examine the relationship 

between hydraulic fracturing and drinking water resources (USHR, 2009). In 2011, EPA began 

research under its “Plan to Study the Potential Impacts of Hydraulic Fracturing on Drinking 

Water Resources.” (US EPA, 2011). The purpose of the overarching study is to assess the 

potential impacts of hydraulic fracturing on drinking water resources, if any, and to identify the 

driving factors that may affect the severity and frequency of such impacts. Scientists are focusing 

primarily on hydraulic fracturing of shale formations to extract natural gas, with some study of 

other oil- and gas-producing formations, including tight sands, and coalbeds. EPA has designed 

the scope of the research around five stages of the hydraulic fracturing water cycle, each 

associated with a primary research question:

Water Acquisition: What are the possible impacts of large volume water withdrawals 

from ground and surface waters on drinking water resources?

Chemical Mixing: What are the possible impacts of hydraulic fracturing fluid surface 

spills on or near well pads on drinking water resources?

Well Injection: What are the possible impacts of the injection and fracturing process on 

drinking water resources?

Flowback and Produced Water: What are the possible impacts of flowback and produced 

water (collectively referred to as “hydraulic fracturing wastewater”) surface spills on or 

near well pads on drinking water resources?

Wastewater Treatment and Waste Disposal: What are the possible impacts of inadequate 

treatment of hydraulic fracturing wastewater on drinking water resources?
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-3

The purpose of this presentation is to summarize ongoing research on hydraulic fracturing 

wastewater and related modeling within this study.

Background

Flowback and produced water, collectively referred to as “hydraulic fracturing wastewater1,” is 

generally stored onsite before being transported for treatment, recycling or disposal. Most 

hydraulic fracturing wastewater is disposed in underground injection control wells (UIC) wells. 

In Pennsylvania, however, wastewater has been treated in wastewater treatment facilities 

(WWTFs), which subsequently discharge treated wastewater to surface water bodies. The extent 

to which common treatment technologies used in WWTFs effectively remove chemicals found in 

hydraulic fracturing wastewater is currently unclear. Depending in part on the concentration of 

chemicals in the effluent, drinking water quality and the treatment processes at public water 

systems (PWSs) that are downstream from WWTFs might be negatively affected. For example, 

bromide in source waters can cause elevated concentrations of brominated disinfection 

byproducts (BR-DBPs) in treated drinking water (Brown et al., 2011; Plewa et al., 2008), which 

are regulated by the National Primary Drinking Water Regulations2.

To learn more about impacts to downstream PWSs, the Pennsylvania Department of the 

Environment asked 25 WWTFs that accept Marcellus wastewater to monitor effluent in March 

2011, for parameters such as radionuclides, total dissolved solids (TDS), alkalinity, chloride, 

sulfate, bromide, gross alpha, radium-226 and -228, and uranium (PA DEP, 2011). The 

department also asked 14 PWSs with surface water intakes downstream from WWTFs that 

accept Marcellus wastewater to test for radionuclides, TDS, pH, alkalinity, chloride, sulfate, and 

bromide (PA DEP, 2011). Bromide and radionuclides are of particular concern in discharges 

because of their carcinogenicity and reproductive and developmental affects.

Wastewater treatability research activities summarized here include an assessment of efficacy of 

common wastewater treatment processes on removing selected chemicals found in hydraulic 

fracturing wastewater and the potential for brominated compounds present in the wastewater to 

form brominated disinfection byproducts (Br-DBPs) during drinking water treatment processes. 

Surface water modeling is considering bromides and radium at public water supplies downstream 

from wastewater treatment facilities that discharge treated hydraulic fracturing wastewater to

surface waters. Finally, source apportionment modeling studies are considering the 

identification and quantification of the source(s) of high bromide and chloride concentrations at 

public water supply intakes downstream from wastewater treatment plans discharging treated 

hydraulic fracturing wastewater to surface waters. As ongoing research activities, results and 

conclusions will not be presented here, but the approach and current status will be summarized.

Wastewater Treatability Studies

The EPA is conducting laboratory experiments to assess the efficacy of conventional wastewater 

treatment processes on selected chemicals found in hydraulic fracturing wastewater. This is 

being dome to provide data to inform the research question: How effective are conventional 

 

1

Produced water is produced from many oil and gas wells and not unique to hydraulic fracturing.

2 Authorized by the Safe Drinking Water Act.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-4

POTWs and commercial treatment systems in removing organic and inorganic contaminants of 

concern in hydraulic fracturing wastewater?

This project focuses on the efficacy of treatment processes at publicly owned treatment works 

(POTWs) and centralized waste treatment facilities (CWTs), since discharge of treated 

wastewater to surface waters provides an opportunity for chemicals found in the effluent to be 

transported to downstream PWS intakes. The fate and transport of chemicals will be examined 

through conventional POTW treatment processes and commercial chemical coagulation/settling 

processes. The objective of this work is to identify the partitioning of selected chemicals between 

solid and aqueous phases and to assess the biodegradation of organic constituents. In addition, 

microbial community health will be monitored in the reactors to identify the point where 

biological processes begin to fail. Contaminants that can pass through treatment processes and 

impact downstream PWS intakes will be identified.

The US EPA will initially analyze the fate and transport of selected hydraulic fracturing–related 

contaminants in wastewater treatment processes, including conventional processes (primary 

clarifier, aeration basin, secondary clarifier), commercial processes (chemical precipitation/ 

filtration and evaporation/distillation), and water reuse processes (pretreatment and filtration). 

The initial phase of this work will involve bench-scale fate and transport studies in a primary 

clarifier followed by 10 liter chemostat reactors seeded with microbial organisms from POTW 

aeration basins. In bench- scale work relevant to CWTs, similar fate and transport studies will be 

performed in chemical coagulation, settling, and filtration processes. In addition to analyzing 

water samples before and after treatment, concentrations and chemical speciation of inorganic 

contaminants in treatment residuals will be examined.

Initial bench-scale studies will focus on establishing thresholds of TDS tolerance in chemostat 

bioreactors. Once the basic salt thresholds have been established, selected chemicals from the 

26R Forms (Chemical Analysis of Residual Waste Annual Reports) will be added to the salt 

stock solutions. Salt concentrations will be kept below the thresholds where effects on the 

biological processes were observed. Potentially biodegradable pollutants (e.g., organics) will be 

measured, and the EPA will attempt to identify breakdown products.

Constituents that are not biodegradable (e.g., elements and anions) will be tracked through the 

treatment process by analyzing system effluent using the appropriate EPA Methods, and by 

analyzing residuals from the primary clarifier and the bioreactors. The results of these benchscale studies will be applied to a pilot-scale system that would target compounds identified in 

bench- scale studies as being the most problematic due to their lack of degradation or removal in 

the treatment process.

For studies on commercial treatment systems using chemical addition/settling, the EPA plans to 

conduct jar tests that employ coagulants/flocculants at appropriate contact and settling times. The 

jar tests will be conducted at the bench-scale using actual hydraulic fracturing wastewater 

samples. EPA will also attempt to mimic evaporative/distillation processes by using thermal 

treatment on actual hydraulic fracturing wastewater samples. Elements in the residuals will also 

be characterized via X-ray diffraction and X-ray absorption microscopy.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-5

Brominated Disinfection Byproduct Precursor Studies

The EPA is assessing the ability of hydraulic fracturing wastewater to contribute to DBP 

formation in drinking water treatment facilities, with a particular focus on the formation of 

brominated DBPs. This work will inform the research question: What are the potential impacts 

from surface water disposal of treated hydraulic fracturing wastewater on drinking water 

treatment facilities?

Wastewaters from hydraulic fracturing processes typically contain high concentrations of TDS, 

including significant concentrations of chloride and bromide. These halogens are difficult to 

remove from wastewater; if discharged from treatment works, they can elevate chloride and 

bromide concentrations in drinking water sources. Upon chlorination at a drinking water 

treatment facility, chloride and bromide can react with naturally occurring organic matter (NOM) 

in the water and lead to the formation of DBPs. Because of their carcinogenicity and 

reproductive and developmental affects, the maximum contaminant levels (MCLs) of the DBPs 

bromate, chlorite, haloacetic acids, and total trihalomethanes (THMs) in finished drinking water 

are regulated by the National Primary Drinking Water Regulations2.

Increased bromide concentrations in drinking water resources can lead to greater total THM 

concentrations on a mass basis and may make it difficult for some PWSs to meet the regulatory 

limits of total THM listing in Table 44 in finished drinking water. As a first step, this project is 

examining the formation of brominated THMs during drinking water treatment processes, 

including bromoform (CHBr3), dibromochloromethane (CHClBr2), and bromodichloromethane 

(CHCl2Br). The formation of haloacetic acids (HAAs) and nitrosamines during drinking water 

treatment processes is also being investigated.3

Reactions of brominated biocides, used in hydraulic fracturing operations with typical drinking 

water disinfectants associated with chlorination or chloramination, are also being explored. 

Brominated biocides are often used in fracturing fluids to minimize biofilm growth. The 

objective of this work is to assess the contribution, if any, to brominated DBP formation and 

identify degradation pathways for brominated biocides.

Three treatments will be applied to high-TDS wastewater samples: (1) in order to account for 

dilution effects, samples will be blended with deionized water at rates that mimic discharge into 

varying flow rates of receiving water; (2) samples will be blended with deionized water with 

NOM additions at concentration ranges typically found in surface waters; and (3) samples will be 

blended with actual surface water samples from rivers that receive treated hydraulic fracturing 

wastewater discharges. All samples will be subjected to formation potential experiments in the 

presence of typical drinking water disinfectants associated with chlorination or chloramination. 

Formation potential measures will be obtained separately for THMs, HAAs, and nitrosamines. 

DBP formation in surface water samples will be compared with DBP formation in deionized 

water. In addition, they will be compared to deionized water fortified with several NOM isolates 

 

3 Nitrosamines are byproducts of drinking water disinfection, typically chloramination, and currently unregulated by the EPA. 

Data collected from the second Unregulated Contaminant Monitoring Rule indicate that nitrosamines are frequently being found 

in PWSs. Nitrosamines are potentially carcinogenic.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-6

from different water sources in order to examine the effects of different NOM on DBP 

formation.

The brominated biocides 2,2-dibromo-3-nitropropionamide and 2-bromo-2-nitrol-1,3-

propanediol, employed in hydraulic fracturing processes, are being subjected to chlorination 

conditions encountered during drinking water treatment. These experiments should provide 

insight on the potential formation of brominated THMs from brominated biocides.

Surface Water Modeling

EPA is using established surface water transport theory and models to identify concentrations of 

selected hydraulic fracturing-relevant chemicals at public water supply intakes located 

downstream from wastewater treatment facilities that discharge treated hydraulic fracturing 

wastewater to rivers. This work is expected to provide data that will be used to answer the 

research question: What are the potential impacts from surface water disposal of treated 

hydraulic fracturing wastewater on drinking water treatment facilities?

Mass balance, empirical, and numerical computer models will be used to estimate generic 

impacts of bromide and radium in wastewater discharges. The models will be based on the 

presence of these chemicals in discharge data from WWTFs in Pennsylvania, impacts to 

downstream PWSs’ ability to meet National Primary Drinking Water Regulations for DBPs and 

radionuclides, and the potential human health impacts from the chemicals.4 Uranium, also a 

radionuclide, was frequently not detected by analytical methods for the discharges, and therefore 

not considered for simulations.

The results of the mass balance model simulate possible impacts during a large volume, high 

concentration discharge without natural attenuation of contaminants. The empirical model and a 

hybrid empirical-numerical model estimate impacts in a more realistic setting with variable 

chemical concentrations, discharge volumes, and flow rates of the receiving surface water. The 

numerical model confirms the results of the empirical and hybrid models. The numerical 

modeling is based on an approach developed for this study from existing methods (Hairer et al., 

1991; Leonard, 2002; Schiesser, 1991; Wallis, 2007). Application of these three types of models 

provides a panoramic view of possible impacts and enhances confidence in the study results.

The generic model results are designed to illustrate the general conditions under which 

discharges might cause impacts on downstream public water supplies. The analysis will include 

the effect of distance to the PWS, discharge concentration, and flow rate in the stream or river, 

among others. The uncertainties in these quantities will be addressed through Monte Carlo 

analysis. A steady-state mass balance model provides an upper-bound impact assessment of the 

transport simulation, and a partially transient approach simulates the temporal variation of 

effluent concentration and discharge. Key data collected to model the transport of potential 

contaminants include actual effluent data from WWTF discharges and receiving water body flow 

rates. Effluent data can be obtained from National Pollutant Discharge Elimination System 

(NPDES) monitoring data reported to states by the dischargers.5 NPDES information also 

documents the design of the industrial treatment plants, which can give insights into the 

 

4 Discharge data for four WWTFs in Pennsylvania that accepted oil and gas wastewater during 2011 are available on the EPA’s 

website at http://www.epa.gov/region3/marcellus_shale/.

5

Information on WWTF discharges in Pennsylvania can be found at https://www.paoilandgasreporting.state.pa.us/.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-7

capabilities of these and similarly designed treatment plants. The U.S. Geological Survey 

(USGS) provides limited water quality and flow rate data from monitoring stations within the 

watersheds of the receiving water bodies. The surface water modeling results will directly 

address the applicable research question by evaluating the possible impacts from a permitted 

release of treated effluent on both a downstream drinking water intake, and in a watershed where 

there may be multiple sources and receptors.6

Currently, sufficient data have been identified to perform generic simulations for the steady-state 

mass balance simulations and hybrid empirical-numerical models with variable effluent 

concentration and plant discharge. For two WWTFs in Pennsylvania, USGS flow data have been 

compiled for segments of the rivers that reach downstream to drinking water intakes (50 to 100 

miles downstream) for the two locations. These data will be used to generate realistic model 

inputs to assess, in a generic sense, the potential impacts of discharges from realistic treatment 

plants.

The EPA-developed hybrid empirical-numerical model has been favorably compared against a 

tracer experiment used by Jobson (1996) in developing the original empirical formulas. 

Calibration or other parameter adjustment was unnecessary for the hybrid model to produce 

accurate results. EPA plans to compare the hybrid model to five more of the tracer experiments 

to cover the range of flow conditions used by Jobson (1996). Additionally, data from the more 

recent Yellowstone River experiment (McCarthy, 2009) are being prepared for testing the hybrid 

model. Similar comparisons of empirical to tracer experiments were performed by Reed and 

Stuckey (2002) for streams in the Susquehanna River Basin. EPA’s Water Quality Simulation 

Package numerical model was set up to simulate the same tracer experiment performed for the 

hybrid model. Additional calibration is planned to refine the results from the Water Quality 

Simulation Package. After completing the evaluation of the hybrid model, the WWTF 

simulations will be completed.

A description of the EPA-developed empirical-numerical model and application of the empirical, 

numerical, and mass balance models to tracer experiments is being developed by EPA scientists, 

and are expected to be submitted for publication in a peer-reviewed journal. The results from 

testing of the models and the analysis of the WWTF effluent data will be included in another 

peer-reviewed journal article.

Source Apportionment Modeling

US EPA is combining data collected from samples of wastewater treatment facility discharges, 

as well as receiving waters with existing modeling programs, to identify the proportion of 

hydraulic fracturing wastewater that may be contributing to contamination at downstream public 

water system intakes. This work has been designed to help inform the research question: What 

are the potential impacts from surface water disposal of treated hydraulic fracturing wastewater 

on drinking water treatment facilities?

 

6

Impacted watersheds may also have other sources of compounds of interest, possibly acid mine drainage and coal-fired utility 

boilers.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-8

This project’s overall goal is to establish an approach whereby surface water samples may be 

evaluated to determine the extent to which hydraulic fracturing wastewaters (treated or 

untreated) may be present, and to distinguish whether any elevated bromide and chloride in those 

samples may be due to hydraulic fracturing or other activities. To accomplish this goal, US EPA 

is (1) quantifying the inorganic chemical composition of discharges in two Pennsylvania river 

systems from WWTFs that accept and treat flowback and produced water, coal-fired utility 

boilers, acid mine drainage, stormwater runoff of roadway deicing material, and other industrial 

sources; (2) investigating the impacts of the discharges by simultaneously collecting multiple 

upstream and downstream samples to evaluate transport and dispersion of inorganic species; and 

(3) estimating the impact of these discharges on downstream bromide and chloride levels at PWS 

intakes using mathematical models.

In this effort, water samples are being collected at five locations on two river systems; each river 

has an existing WWTF that is currently accepting hydraulic fracturing wastewater for treatment. 

Source profiles for significant sources, such as hydraulic fracturing wastewater, WWTF effluent, 

coal-fired utility boiler discharge, acid mine drainage, and stormwater runoff from roadway 

deicing, will be developed from samples collected from these sources during the study. 

Computer models will then be used to compare data from these river systems to chemical and 

isotopic composition profiles obtained from potential sources.

US EPA will analyze the river samples and effluent samples according to existing US EPA 

methods. Inorganic ions (anions and cations) are being determined by ion chromatography. 

Inorganic elements are being determined using a combination of inductively coupled plasma 

optical emission spectroscopy for high-concentration elements, and high-resolution magnetic 

sector field inductively coupled plasma mass spectrometry for low concentration elements. 

Additionally, the characteristic strontium (Sr) ratios (87Sr/86Sr; 0.7101– 0.7121) in Marcellus 

Shale brines are extremely sensitive tracers, and elevated concentrations of readily water soluble 

strontium are present in the hydraulic fracturing wastewaters (Chapman et al., 2012). Isotope 

analyses for 87Sr/86Sr are being conducted on a subset (~20%) of samples by thermal ionization 

mass spectrometry to corroborate source apportionment modeling results.

US EPA is using the data gathered through the analyses described above to support source 

apportionment modeling. This effort will use peer-reviewed receptor models to identify and 

quantify the relative contribution of different contaminant source types to environmental 

samples.7EPA-implemented models and commercial off-the-shelf software are being used to 

analyze the data from this particular study (e.g., Unmix, Positive Matrix Factorization, chemical 

mass balance). These models have previously been used to evaluate a wide range of 

environmental data for air, soil, and sediments (Cao et al., 2011; Pancras et al., 2011; 

Soonthornnonda and Christensen, 2008), and are now being used for emerging issues, such as 

this application.

River samples collected near PWS intakes are being evaluated to discern the contributing sources 

(e.g., hydraulic fracturing wastewater or acid mine drainage) of bromide and chloride to those 

stream waters. Receptor models require a comprehensive analysis of environmental samples to 

provide a sufficient number of constituents to identify and separate the impacts of different 

 

7

The receptor model, Positive Matrix Factorization, was peer-reviewed in 2007 (version 1.1) and 2011 (version 4.2), and Unmix 

(version 5.0) underwent peer review in 2007.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-9

source types. Contaminant sources may be distinguished by unique ranges of chemical species 

and their concentrations; the models provide quantitative estimates of the source type 

contributions along with robust uncertainty estimates.

Summary

The ongoing wastewater treatment and related modeling activities that are part of US EPA’s 

“Plan to Study the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources,” 

have been summarized here. Using a variety of laboratory and bench-scale experiments, as well 

as modeling tools, these research activities focus on key factors of concern related to hydraulic 

fracturing wastewater, such as bromides and radionuclides. More information about each of these 

study activities can be found in “EPA’s Study of the Potential Impacts of Hydraulic Fracturing 

on Drinking Water Resources: Progress Report.” (US EPA, 2012). Results from these research 

projects will be included in the final report of the EPA study, which is expected to be released 

for public comment and peer review in 2014.

References

Brown, D., Bridgeman, J. and West, J. R. (2011). “Predicting chlorine decay and THM 

formation in water supply systems.” Reviews in Environmental Science and 

Biotechnology 10 (1): 79-99.

Cao, J., Li, H., Chow, J. C., Watson, J. G., Lee, S., Rong, B., Dong, J. G. and Ho, K. F. (2011). 

“Chemical composition of indoor and outdoor atmospheric particles at Emperor Qin's 

Terra-cotta Museum.” Aerosol and Air Quality Research, 11 (1): 70-79.

Chapman, E. C., Capo, R. C., Stewart, B. W., Kirby, C.S., , Hammack, R. W., Schroeder, K. T. 

andEdenborn, H. M. (2012). “Geochemical and strontium isotope characterization of 

produced water from Marcellus shale natural gas extraction.” Environmental Science & 

Technology, 46 (6): 3545-3553.

Hairer, E., Norsett, S. P. and Wanner, G. (1991). “Solving Ordinary Differential Equations I: 

Nonstiff Problems.” Springer-Verlag, Berlin, Germany.

Jobson, H. E. (1996). “Prediction of Traveltime and Longitudinal Dispersion in Rivers and 

Streams.” Water-Resources Investigations Report 96-4013. U.S. Geological Survey. 72 p. 

<http://water.usgs.gov/osw/pubs/wrir964013header.html>

Leonard, B. P. (2002). “Stability of explicit advection schemes. The balance point location rule.” 

International Journal for Numerical Methods in Fluids, 38 (5): 471-514.

McCarthy (2009). “Travel Times, Streamflow Velocities, and Dispersion Rates in the 

Yellowstone River, Montana.” Scientific Investigations Report 2009-5261. U.S. 

Geological Survey. 25 p. < http://pubs.usgs.gov/sir/2009/5261/>

Pancras, J. P., Vedantham, R., Landis, M. S., Norris, G. A. and Ondov, J. M. (2011). 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-10

“Application of EPA unmix and non-parametric wind regression on high time resolution 

trace elements and speciated mercury in Tampa, Florida aerosol.” Environmental Science 

& Technology, 45 (8): 3511-3518.

Pennsylvania Department of Environmental Protection (PA DEP) (2011). “Letter from 

Pennsylvania Department of the Environment to US EPA Region 3 Administrator Shawn 

Garvin.” <http://www.epa.gov/region3/marcellus_shale/Shawn_Garvin_LetterApril_6_2011.pdf> Attachments: 

<http://www.epa.gov/region3/marcellus_shale?#inforeqsbyPA DEP> (Accessed April 6, 

2011).

Plewa, M. J., Muellner, M. G., Richardson, S. D., Fasano, F., Buettner, K. M., Woo, Y.-T., 

McKague, B. and Wagner, E. D. (2008). “Occurrence, synthesis and mammalian cell 

cytotoxicity and genotoxicity of haloacetamides: an emerging class of nitrogenous 

drinking water disinfection byproducts.” Environmental Science & Technology, 42 (3): 

955-961.

Reed, L. A. and Stuckey, M. A. (2002). “Prediction of Velocities for a Range of Streamflow 

Conditions in Pennsylvania.” Water-Resources Investigations Report 01-4214. U.S. 

Geological Survey. 13 p. <http://pa.water.usgs.gov/reports/wrir01-4214.pdf>

Schiesser, W. E. (1991). “The Numerical Method-of-Lines: Integration of Partial Differential 

Equations.” Academic Press, San Diego, California.

Soonthornnonda, P. and Christensen, E. (2008). “Source apportionment of pollutants and flows 

of combined sewer wastewater.” Water Research 42 (8-9): 1989-1998

U.S. Environmental Protection Agency (US EPA) (2012). “EPA’s Study of the Potential Impacts 

of Hydraulic Fracturing on Drinking Water Resources: Progress Report.” U.S. 

Environmental Protection Agency, Washington, D.C., Pub No. EPA 601/R-12/011. 

<http://www2.epa.gov/hfstudy/study-potential-impacts-hydraulic-fracturing-drinkingwater-resources-progress-report-0>

U.S. Environmental Protection Agency (US EPA) (2011). “Plan to Study the Potential Impacts 

of Hydraulic Fracturing on Drinking Water Resources.” U.S. Environmental Protection 

Agency, Washington, D.C., Pub. No. EPA 600/R-11/112. 

<http://www2.epa.gov/hfstudy/plan-study-potential-impacts-hydraulic-fracturingdrinking-water-resources-epa600r-11122>

U.S. House of Representatives (2009). “Appropriations Committee Report for the Department of 

the Interior, Environment, and Related Agencies Appropriations Bill, HR 2996.” 

<http://www.gpo.gov/fdsys/pkg/CRPT-111hrpt180/pdf/CRPT-111hrpt180.pdf> 

(Accessed December 6, 2012).

Wallis, S. (2007). “The numerical solution of the advection-dispersion equation: a review of 

some basic principles.” Acta Geophysica, 55 (1): 85-94.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-11

Achieving Zero Discharge of Water from

Non-Conventional Oil & Gas Hydrofracturing Activities

Carl E. Adams, Jr.

ENVIRON International Corporation

Introduction/Background

The rapid expansion of non-conventional oil and gas hydraulic fracturing activities has created 

anxiety in inexperienced or local citizens in the vicinity of the activities. Foremost among these 

concerns are potential water sustainability issues, especially surface contamination from 

stormwater and spills and insufficient management of the water from the fractured well itself. In 

June 2012, the concept presented herein was initiated to enhance sustainability and minimize all 

environmental impacts, particularly water-related issues.

Emerging policy on hydraulic fracturing activity is being debated between the various agencies 

(US EPA, states, local municipalities). The major debate will focus on pretreatment for 

municipal and commercial treatment vs. injection back into new and expired hydraulic fracturing 

wells. The process described herein is flexible to adapt to emerging and more stringent criteria.

The major objectives of this project were to:

Reduce trucking and acquisition costs of freshwater supplement

Reduce off-site trucking and disposal costs of associated wastewaters (Flowback & 

Produced Waters)

Reduce quantity of chemical additives into the fracturing fluids

Organize and implement the project along Industrial Wastewater Management 

methodology protocols

Approach

ENVIRON’S approach to this complex project was to organize and manage it as a traditional 

Industrial Wastewater Management project. This brought a perspective that other practitioners 

had not incorporated into their project organization.

The basic agenda was to meet with on-site operators, hydraulic fracturing water managers, global 

chemical suppliers and technology providers, especially various filtration manufacturers. The 

team collected, assimilated and correlated available data, consistent with industrial wastewater 

management protocols. 

The inlet characteristics and outlet criteria (for both recycle and discharge disposal) were 

evaluated and comprehensive data correlations assembled to allow evaluation of chemistry 

techniques and application of appropriate, cost-effective technologies. A comprehensive 

technology evaluation and selection process was then conducted to develop a technically reliable 

and operationally predictable process train. An economic model was then developed to compare 

capital and operational costs of current and predicted management approaches. Over 90 wells 

were surveyed and utilized for the data processing
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-12

Results and Discussion

The most significant parameters for a process design are: 1) water flow rate; 2) water volume 

accumulation during a fracture; and, 3) water constituent quality. The significance of these 

design elements is:

Flow Rate

o Influences sizing and capital cost of surge/handling/pretreatment facilities

Accumulative Flow Volume

o Influences required equalization/storage requirements

o Influence on blending management of TDS concentrations in recycled Flowback 

and Produced Water

Water Constituent Concentration

o Influences supplemental chemical additives

o Defines technology required for discharge or recycle

o Influences selected pretreatment technology used for reinjection/recycle of 

wastewaters

o Major influence on on-going operational costs

Water Flow Rate and Volume Accumulation: Flowback and Produced Waters

From the beginning, the project was treated as a traditional industrial wastewater management 

activity. Over 90 wells in the Marcellus shale formations were evaluated based on available data. 

A database was developed on controlled and uncontrolled water sources and outlets (Water 

Lifecycle) as shown below:

Controlled Sources in the Water Lifecycle

o Surface water (river, lake, POTW treated effluent, mining wastewater)

o Subsurface (groundwater: potable, non-potable)

Uncontrolled Sources

o Rain/Storm water (collected and utilized)

Controlled Outlets in the Water Lifecycle

o Trucked/Piped to disposal 

 Injection well

 POTW

 Commercial Disposal

 On-site treatment and direct discharge to receiving surface water

o Reused on site

o Reused at another site

o Sanitary & utilities

Uncontrolled Outlets

o Loss to formation

o Leaks & spills

o Evaporation
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-13

Figures 1, 2 and 3 present the flow data for Flowback Water and statistical analysis to develop 

surge and forward flows required for process design. The same approach was used for Produced 

Water. The correlated flow results are given in Table 1.

Figure 1. Water Flow Rates During Flowback Period (2-3 Weeks)

Figure 2. Water Rate Statistical Summary

At an online pumping rate of 100 bbls/

hr (70 gpm) will accumulate 70 x 0.5

bblsx70 hrs = 102,000 gals. A

Containmen t 0f 200,000 gals would

be suitable.

Differential

pumping rate = 70

bbls/hr (49 gpm) 

Time of differential

pumping = 70 hrs

An economical option to the surge tank

would be a control valve on the well

discharge, restricting flow top 100 bbls/

day. Thus, rather than surging the flow for

~80 hours, the flow could be constrained

for 200 hours at 70 gpm then reduced for

the remaining Flowback period.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-14

Figure 3. Water Flow Accumulation During Flowback Period (2-3 Weeks)

Table 1. Summary of Water Flow Rates during Flowback and Produced Water Periods

Water Category Average Maximum Typical

Fracturing Injection Water (gallons)1520,0000 9,000,000 6,500,000

Flowback Water in First 1-3 Weeks

% of Water Injected 8.9% 20.0% 10.0%

Flowback Cumulative 360,000 780,000 650,000

Produced Water (gpd/days to 1 mil gal)2

21 days to 50 days 3652 / 273 12,713 6,300 / 158

50 days to 250 days 1,001 / 1,000 1,990 3,780 / 264

250 days to 1 year 452 / 2,212 1,066 2,630 / 380

1 year to end of well 96 / 10,416 13,158 1,300 / 769

1

Flowback statistics based on 25 wells

2 Produced Water statistics based on 64 wells

Water Quality Constituents: Flowback and Produced Waters

Many chemicals can be considered in hydraulic fracturing activities, which are naturally 

occurring or which are added to enhance or protect the integrity of the fracturing process. 

Basically, the chemicals, which occur in the hydraulic fracturing wastewaters, either originate in 

the strata from ages of dissolution or are added to enhance the hydraulic fracturing process.

1. Major Water Quality Constituents: Naturally occurring (equilibrium from dissolution, 

only a little from acid dissolution)

a. Calcium

b. Barium
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-15

c. Magnesium

d. Iron, ferrous 

e. Chlorides

f. Total Dissolved Solids

g. Total Suspended Solids

h. NORM (radium, thorium, strontium, radon, etc.)

i. Heavy Metals e.g., As, Cd, Cr+6, Cu, Hg, Se, Zn 

Figure 4 is an example of the inorganic ion concentrations as they accumulate due in the 

Flowback Water due to equilibrium dissolution. Table 2 summarizes the Flowback and Produced 

Water ionic concentrations that can be expected in the return water to the surface.

Figure 4. Flowback Water Chemistry Interactions

2. Chemicals added to injected water to enhance/stabilize hydraulic fracturing activities.

The major chemical additives and cost comparisons to facilitate gas completion are:

a. Friction Reducers (decreases water flow head loss): 50-70% of cost

b. Biocides (prevents odors and sulfide corrosion): 20-30% of cost

c. Anti-Scalants (minimizes precipitation and scaling, specifically, Calcium, 

Barium, Magnesium, Iron): 10-15% of cost

d. Remaining chemicals: 5-10% of cost

Costs are for additive chemicals only, do not include sand or guar.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-16

Table 2. Summary Flowback & Produced Water Quality Concentrations

Parameter Units

Flowback Water Produced Water

Average Minimum Maximum 50th

Percentile

95th

Percentile Average Maximum

Total 

Hardness

mg/L 3,077 116.1 104,090 27,624 89,698 15,100 29,000

Total 

Alkalinity

mg/L 428 16.0 3,301 400 863 -- --

Total 

Dissolved 

Solids

mg/L 10,9156 10,013 331,202 102,550 298,289 114,449 177,310

Chlorides mg/L 69,315 5,999 196,956 65,985 187,158 70,400 104,000

Sulphates mg/L 8.4 0.0 500 0.0 30 -- --

Calcium mg/L 9,861 30.5 36,671 8,737 31,461 13,767 26,400

Magnesium mg/L 1,330 5.8 17,014 1,118 3,160 1,333 2,600

Sodium mg/L 27,617 1.0 96,975 24,700 83,695 27,500 40,500

Potassium mg/L 174 1.0 500 200 300 690 1,600

Total Iron mg/L 145 0.6 4,600 43 688 753 2,200

Barium mg/L 6,506 95.0 96,000 2,300 55,800 6 10

Suspended 

Solids

mg/L 896 20.0 4,110 900 1,792 109 150

Ferrous 

Iron

mg/L 11.0 0.0 108 4.3 44 -- --

Biochemica

l Oxygen 

Demand

mg/L -- -- -- -- -- 1,100 1,400

Notes:

1) Statistics based on all samples reported as “Flowback” in EXCO Pa Database.

2) Statistics based on 3 samples representing 2 locations in Pennsylvania from September 1986 as reported by the 

American Petroleum Institute.

3) Numbers in red are calculated.

Comments on Water Chemistry Friction Reducers: The concern with friction reducers is the 

biggest issue in reuse of a high salinity (TDS) water from a blend of Flowback and Produced 

Waters. Generally, a form of anionic polyacrylamide is preferred to control friction during the 

injection of pressurized water. Divalent cations are considered a major problem, and, if so, 

cationic polyacrylamides might resolve the issue. These cationic polymers are more expensive, 

but fewer chemicals are required. Polymers are not a fouling issue due to tight shale; they are a 

surface fouling phenomenon only. The higher TDS, anticipated in this project, may actually aid 

in friction reduction. Polymeric and non-polymeric scaling inhibitors have also had value as 

friction reducers.

Biocides: Biocides are used to control bioactivity of sulfate reducers (heterotrophic bacteria in 

an oxygen-depleted environment), and the resulting “souring” and corrosion from hydrogen 

sulfide (odors) production transforms to sulfuric acid (corrosion) at compatible pH values. 

The most common biocide during hydraulic fracturing is Gluteraldehyde + Quaternary Amines. 

Sometimes THPS is utilized. Oxidizers, such as chlorine, bromine or ozone, have side effects or 

are prohibitally expensive. These oxidants are very effective biocides, but can be consumed 

inefficiently in the presence of organics. The presence of dissolved organics will substantially 

increase the cost of oxidizing biocides, as well as generate dechlorinated and brominated toxic 

organics.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-17

Peracetic acid is an effective non-oxidizing biocide without the disadvantages of non-selective 

oxidation. However, there is limited residual inhibition of bioactivity with peracetic acid. It may 

be cost-effective to use an economical non-oxidant biocide (peracetic acid, etc.), followed with 

lower dosages of a traditional longer acting biocide.

It may even be feasible to add an electron acceptor, such as nitrate (as sodium nitrate or nitric 

acid) to eliminate sulfate as a problem. Nitrate is preferred over sulfate by anoxic biomass, 

containing sulfate and nitrate reducing bacteria (same microbes), and releases harmless nitrogen 

gas instead of toxic and corrosive sulfide.

Anti-Scalants: Classical scalants in hydraulic fracturing are Calcium, Barium, Magnesium and 

Iron. Scaling forms from flash precipitation on a surface, and there is software available to 

reliably predict implications of scalants in varied waters. It is feasible to utilize a scaling model 

to scan various conditions.

The prevailing thought is that the high concentrations of ionic scalants in Flowback Water are 

due to equilibrium dissolution and will not increase substantially with recycle. Thus, only a slight 

amount of Flowback may require pretreatment for scalant precipitation and removal by filtration.

Summary of Discussion

Based on the data characterization (both flow and quality), a cost-effective water management 

concept was developed. This concept realizes that all of the Flowback and Produced Waters, 

blended in appropriate quantities, can be recycled into subsequent well activity. It is also 

promising that some of the chemical additives can be recycled, and the need for other chemical 

additions may be reduced due to correct blending of high TDS waters (friction reducers) and 

pretreatment of bioactivity with oxidants (biocides, e.g., peracetic acid).

Technology Evaluation and Selection

Based on the summary observations noted above, complete recycle of all Flowback and 

Produced Waters is the most appealing option. It is recommended that this option be pursued to 

develop a reliable performance and cost estimate. This option is referred to herein as the 

“Achieving Zero Discharge of Water Initiative.”

For the Technology Review and Evaluation, every proven technology that has been piloted or 

implemented full-scale was examined and only those, which were deemed to fit the selection 

criteria, were chosen for further consideration. The major technology categories evaluated were:

Adsorption/Exchange

Chemical/Catalytic Conversion

Chemical Oxidation

Concentration/Volume Reduction

Membrane Processes

Physical Separation
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-18

Thermal/Catalytic Destruction

Biological Oxidation/Reduction/Conversion (presented at end)

Miscellaneous

The constituents to be treated via two optional outlets, i.e., pretreated (recycle) or final treated 

(discharge to receiving water, POTW or commercial industrial treatment facilities) are given 

below:

Processes For Treatment & Discharge to Receiving Water, 

POTW or Commercial Treatment Facilities

Processes For Recycle

pH adjustment

Oil removal

Suspended solids removal

Metals removal (including NORM radioactivity)

Evaporation (some cases)

Solids handling & disposal

Inorganic salts removal

Soluble organics removal

pH adjustment

Oil removal

Suspended solids removal

Scalant removal

Solids handling & 

disposal

Technology Evaluation Categories

Technical Feasibility

Cost-Effectiveness

Operational Reliability

Environmental Issues

Aesthetic Considerations

Achieving Zero Discharge of Water from Hydrofracturing Activities

The main premise of this concept is to operate a suspended solids removal pretreatment step of 

all combined wastewaters. The contaminants, such as NORM, heavy metals, mercury, organics 

and TDS, etc., can be chemically adjusted to remain in solution and, thus, be reinjected into 

subsequent well activities. It is emphasized that 80 to 90% of the injected fracturing water (on 

the order of 5.4 mil gallons) will remain in the shale strata, and only 0.4 to 0.8 mil gallons will 

resurface as Flowback Water. This Flowback Water will be blended with a small percentage (10 

to 30%) of Produced Water and, then combined with 4 to 5 mil gallons of Fresh Water for the 

new “fracture.”

Thus, the technology review was oriented towards those technologies and methodologies that are 

most effective for this option, specifically, filtration alternatives. Oxidation, tight membranes 

(both micro and nano membrane filtration were considered) and biocide oxidants were evaluated.

All containment will possess floating roofs so that no air is emitted and no rain or wind spillage 

or overflow can occur. The pad will be “bathtubbed” so that all pad spills (truck loading, etc.) 

and stormwater will be contained and routed to a sump for recycle. This concept will involve:
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-19

Minimal containment (with no environmental exposure to air or surface/ground water or 

soils).

Pumped blending of Flowback and Produced Waters to maintain a predictable TDS 

blend.

Chemical addition to preferentially precipitate selected constituents, if required.

Cost-effective, staged filtration (plate & frame or belt press, followed by polishing filter)

Ease of residual solids handling, with either on-site or off-site disposal

Final Process Train

1. Surge / Containment Tanks

a. Bladder & swimming pool

b. Plastic, covered

c. Erected within lined earthern basin

2. Various Pumps

a. Materials designed for high brine concentration

3. In-line pH Control System

4. In-line Chemical Addition System for Pretreatment (not fracturing chemicals)

a. Coagulant, chelation, polymer, etc.

5. Filter /Dewatering Equipment: one step solids handling

6. Straining Filtration Polishing to Low Levels of Suspended Constituents for Reinjection

The process train is schematically presented in Figure 5.

Figure 5. Concept: Achieving Zero Discharge of Water
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-20

The implementation goals were all achieved:

1. 100% achievement of performance and operations

2. Environmentally sound with no contact with air, groundwater, surface water and soils

3. Cost-effective

4. Maximum flexibility to apply to any hydraulic fracturing activity globally

5. Modularly expandable to accommodate emerging regulatory criteria

Thus, the achievement of a 100% recycle or Zero Discharge of Water Initiative has been 

achieved, subject to treatability screening and confirmation. In sum, the final program will result 

in:

1. A reliable, predictable and environmentally sensitive program, 

2. A cost-effective solution

3. De-risking the hydraulic fracturing process

4. Increased and improved gas completion

5. Facilitating environmental permitting while reducing public concerns for future hydraulic 

fracturing activities.

A reasonable bench-scale screening investigation will be conducted to effectively delineate the 

performance conformation and cost-effective feasibility of the Achieving Zero Discharge of 

Water.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-21

From Pilot Study to Daily Processing Warren, Ohio’s Documentary to Hydraulic 

Fracturing Wastewater Treatment

Thomas A. Angelo

City of Warren, Ohio

The statements made during the workshop do not represent the views or opinions of EPA.

The claims made by participants have not been verified or endorsed by EPA.

Overview

In May of 2009, The City of Warren and Patriot Water Treatment LLC began discussions with 

the Ohio Environmental Protection Agency (OEPA) to initiate the treatment of brine water from 

the Marcellus Shale. A series of letters and meetings culminated to a letter issued to Warren by 

OEPA to perform an eight (8) week pilot study to “clearly identify the amount of brine that 

Warren can receive without causing WWTP or water quality issues.”

Charged with this task, Warren first had a whole effluent toxicity (WET) test accomplished on 

September 4, 2009 to determine the ceiling of brine water acceptance. This demonstrated that the 

facility could accept up to 664,000 gallons of brine water at 50,000 mg/l TDS before toxic 

conditions caused a water flea kill. This was based on an 8 MGD flow. Knowing that typical 

flow rates are approximately 13.38 MGD allowed for a protective buffer of 5.38 MGD dilution 

ratio.

An organizational meeting was held January 8, 2010 to review current information and to set 

guidelines for the pilot study. The guidelines were set as follows:

Patriot Water Systems would supply ten 20,000 gallon frac tanks.

The tanks would be connected together to create one 100,000 gallon mixing system.

Brine water would be re-circulated in the combined tanks to create a homogeneous mix.

The initial mix will be tested for the parameters as defined by OEPA.

The City will sample influent, effluent, upstream and downstream prior to the discharge 

of brine water to develop a baseline concentration of TDS.

The City would conduct a live, 8 week, phased in trial to monitor and record effects on 

treatment processes, accumulation loading and receiving stream TDS.

The maximum amount of TDS in the brine water will not exceed 50,000 mg/l.

Brine water will be phased in as follows (all flows will be over an 8 hour period):

o Week 1 – 5 days at 20,000 gallons 

o Week 2 – 5 days at 40,000 gallons

o Week 3 – 5 days at 60,000 gallons

o Week 4 – 5 days at 80,000 gallons

o Week 5 – 5 days at 100,000 gallons

o Week 6 – 5 days at 100,000 gallons

o Week 7 – 5 days at 100,000 gallons

o Week 8 – 5 days at 100,000 gallons

Testing will be accomplished as defined in Addenda 3 (revised 3/1/10).
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-22

The pilot study was initiated on Tuesday, February 9, 2010. This required a deviation from the 

schedule because the first week did not start on a Monday. As a result, week 1 only had 4 days 

of discharge. The pilot was postponed mid-way through week 2 because source water wasn’t 

available due to extreme weather conditions making the remote well site locations inaccessible 

to truck traffic. The pilot study resumed on March 1, 2010 at 40,000 gallons per day and 

followed the documented schedule throughout the remainder of the study.

Baseline Sampling

Initial baseline testing was accomplished on the river and plant flow to determine TDS levels 

prior to start-up of the pilot study. The baseline levels are as follows:

Baseline Levels TDS Chloride

Raw 584 143

Final 599 157

Up 336 70

Down 332 60

Liquid Sludge 296

Initial radioactivity sampling

Collect date 2/17/10

Parameter Results Units

Gamma Scan All other nuclides <LLD pCi/L

K-40 2.6E+02 +/- 2.6E+01 pCi/L

Ram Chandrasekar, Ph. D., Manager of Lab Operations for the Bureau of Public Health 

Laboratories, Ohio Department of Health, provided this explanation on why Thorium tests were 

not conducted:

Subject: Thorium versus Gross Alpha

ODH Lab methods for radiological testing includes gross alpha screen which includes alpha 

emitted by Thorium nuclides. Hence if the gross alpha value is below the threshold value, there 

is no need to perform the Thorium estimation. When the initial gross alpha value is high, 

separate Thorium determination is required to identify the level.

Pilot Study

The pilot study commenced as scheduled with no other interruptions except for the one noted 

above. Sampling was accomplished as scheduled. OEPA was on site March 17, and March 31, 

2010 and conducted sampling. At the time of this writing, the results of these samples have not 

been received.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-23

TDS Overview 

Sludge 

Three (3) sludge samples were tested for Chlorides during the pilot study. The results of these 

samples are: 

Sample Date Chloride mg/Kg

2/17/2010 250

4/05/2010 184

4/16/2010 456

The increase in Chlorides in the sludge potentially can be a result of TDS becoming colloquial 

solids and settling. However, one data point does not provide sufficient evidence to make a clear 

determination. Therefore, additional observations will be necessary in order to see if this is 

actually occurring. If this is a fact, than a percentage of the brine water is actually being treated. 

Additional observations will allow for a percentage of treatment to be determined if this 

continues as a trend.

Raw Influent 

The average raw TDS did not increase significantly over the 8 week pilot study. Raw TDS 

average increased to 679 mg/l which is approximately 16% over the baseline of 584 mg/l. Raw 

chlorides averaged 239 mg/l which is approximately 67% more than the baseline of 143 mg/l. 

These increases are most likely due to seasonal fluctuations within the collection system as a 

result of user operations or seasonal runoff from spring rains. (Raw does not have any Patriot 

Influence or plant return flows) 

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Raw TDS

TDS
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-24

0

500

1000

1500

2000

2500

3000

2.12.10

3.2.103.4.103.8.10

3.10.103.12.103.16.103.18.103.22.103.24.103.26.103.30.10

4.1.104.5.104.7.104.9.10

4.13.104.15.10

Raw Conductivity

Conductivity

Final Effluent 

The average final effluent TDS increased by 47.8% above the baseline to 885 mg/l and the 

average final effluent Chlorides increased by 122% over the baseline to 348 mg/l. This was 

expected as most of the TDS would pass through the system. However, since raw chlorides 

increased at a greater percentage than raw TDS, it cannot be ruled out that seasonal fluctuations 

within the collection system, as a result of user operations and spring rains, may be causing these 

increases. The higher increases in chlorides in both the raw and final could have resulted from 

runoff water from the roads entering the collection system during early spring rains. These rains 

would have carried additional salt that had acuminated from winter de-icing procedures and was 

washed off the roads with the spring rains. Infiltration and Inflow into the collection system 

would have allowed this additional source of salts to add to the overall total. While the timeline, 

0

200

400

600

800

1000

1200

2.10.102.12.10

3.2.103.4.103.8.10

3.10.103.12.103.16.103.18.103.22.103.24.103.26.103.30.10

4.1.104.5.104.7.104.9.10

4.13.104.15.10

Raw Chloride

Chloride
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-25

as demonstrated by the graphs below, suggest that this hypothesis may be accurate, it also 

coincides with the increase to 100,000 gallons per day discharge of brine. Additional 

observations, during this critical period of time, will help to establish if the hypothesis is 

accurate.

0

500

1000

1500

2000

2500

3000

3500

Final Conductivity

Conductivity

0

500

1000

1500

2000

2500

Final TDS

TDS
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-26

River - Upstream 

The average Upstream River TDS of 348 mg/l remained close to the baseline value of 336 mg/l. 

This represents an increase of 3.6%. However, the average chlorides, at 123 mg/l, were 76% 

higher than the baseline of 70 mg/l. This is most likely due to seasonal de-icing practices where 

salts applied to roadways were washed into the river from storm outlets. 

0

200

400

600

800

1000

1200

2.10.102.12.10

3.2.103.4.103.8.10

3.10.103.12.103.16.103.18.103.22.103.24.103.26.103.30.10

4.1.104.5.104.7.104.9.10

4.13.104.15.10

Final Chloride

Chloride

0

100

200

300

400

500

600

700

800

900

Upstream Conductivity

Conductivity
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-27

0

50

100

150

200

250

2.9.10

2.12.102.16.102.17.102.19.10

2.23.10*

2.24.102.26.10

3.1.103.2.103.5.103.8.103.9.10

3.12.103.15.103.17.103.19.103.22.103.24.103.26.103.29.103.31.10

4.2.104.5.104.6.104.9.10

4.12.104.14.10

Upstream Chloride

Chloride

0

100

200

300

400

500

600

2.9.10

2.12.102.16.102.17.102.19.10

2.23.10*

2.24.102.26.10

3.1.103.2.103.5.103.8.103.9.10

3.12.103.15.103.17.103.19.103.22.103.24.103.26.103.29.103.31.10

4.2.104.5.104.6.104.9.10

4.12.104.14.10

Upstream TDS

TDS
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-28

River – Downstream 

The average Downstream River TDS of 364 mg/l remained close to the baseline value of 332 

mg/l. This represents an increase of 9.7%. However, the average chlorides, at 121 mg/l, were 

81% higher than the baseline of 67 mg/l. The majority of this increase is most likely due to 

seasonal de-icing practices where salts applied to roadways were washed into the river from 

storm outlets. This is evidenced by the deviation as already noted in the Upstream Chlorides. The 

additional increase of 5% from Upstream to Downstream would include chlorides from nonpoint sources along the river way and the introduction of chlorides from the brine water study. 

0

100

200

300

400

500

600

700

800

2.9.10

2.12.102.16.102.17.102.19.10

2.23.10*

2.24.102.26.10

3.1.103.2.103.5.103.8.103.9.10

3.12.103.15.103.17.103.19.103.22.103.24.103.26.103.29.103.31.10

4.2.104.5.104.6.104.9.10

Downstream Conductivity

Conductivity
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-29

0

100

200

300

400

500

600

Downstream TDS

TDS

0

20

40

60

80

100

120

140

160

180

200

Downstream Chloride

Chloride
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-30

Toxicology 

Date Ceriodaphnia dubia Pimephales promelas

TUa TUc TUa TUc

February 20, 2010 AA AA - -

March 6, 2010 AA AA - -

March 13, 2010 AA AA - -

March 20, 2010 AA AA - -

March 27, 2010 AA AA - -

April 3, 2010 AA 1.8 - -

April 10, 2010 AA AA - -

April 17, 2010 AA AA AA AA

Patriot Water Treatment in conjunction with Warren WWTP performed 8 weeks of chronic toxicity 

testing to determine whether the release of brine from Patriot Water Treatment would impact the water 

quality of Warren WWTP effluent discharged from Outfall 001. Due to the fact that increased salt 

concentrations impact Ceriodaphnia dubia more readily than the Pimephales promelas, the water fleas 

were the primary species used in this study, however, during the last week of testing the minnows were 

subjected to the brine water also to investigate any potential impacts. The largest impacts were observed 

in the upstream water which is outside of the influence of the effluent. These effects are not indicative of 

toxicity as a result of Warren’s effluent or Patriot’s brine water. The two testing events that indicated 

toxicity in the upstream receiving water showed that the toxicity was reduced or no longer present in the 

far field water samples. Overall the results of this study have indicated that if Patriot Water Treatment 

discharges a consistent amount of brine water over an extended period of time then there will be no 

adverse changes in the water quality of Warren WWTP or in the Mahoning River downstream of outfall 

001.

Daily Chloride Loading to the River

This information provides a better model of loading in terms of pounds of chlorides to the river. To 

achieve this, I obtained the chart from USGS that shows the Mahoning River flow in cubic feet per 

second. I than broke out the dates that the study occurred and totaled the flow, dividing by the total 

number of days to establish an average daily flow in cubic feet per second. I converted this number to 

million gallons per day and used this to calculate pounds applied. The following tables demonstrate the 

results of these calculations.

BASELINE DAILY CHLORIDE LOADINGS

Upstream Downstream Plant

Avg Avg Avg

Avg Daily Daily Daily

River Flow Load Load Load

MGD lbs/day lbs/day lbs/day

867.27 506,314.39 484,615.20 20,439.42
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-31

STUDY RESULTS - DAILY CHLORIDE LOADINGS

Upstream Downstream Plant Effluent

Avg Peak Avg Peak Avg Peak

Avg Daily Daily Daily Daily Avg Daily Daily

River Flow Load Load Load Load

Plant 

Flow Load Load

MGD lbs/day lbs/day lbs/day lbs/day MGD lbs/day lbs/day

867.27 852,488.76 1,612,972.97 873,134.10 1,446,612.53 15.61 46,867.46 118,995.12

% Over Baseline 168.37 318.57 180.17 298.51 229.30 582.18

Lbs. Over Baseline 346,174.38 1,106,658.59 388,518.90 961,997.33 26,428.04 98,555.70

This information demonstrates that the river was able to assimilate a peak daily load of chloride 318% 

greater than the baseline loading without any toxicology issues. In total pounds applied this means that an 

additional 1,106,658 pounds of chlorides over baseline was assimilated without adverse effects to the 

river biology. Warren’s highest peak daily loading of chloride was only 118,995 pounds.

2010 Pilot Study Conclusion

The 8 week Pilot Study demonstrated that a controlled discharge of brine water into Warren’s 

WWTP did not have adverse water quality impacts to the treatment facility or receiving stream. 

The Study supports the initial toxicology test that indicated that Warren would be able to accept 

up to 664,000 gallons per day of brine water at a maximum limit of 50,000 mg/l TDS at 8 MGD 

daily plant flows. The 8 MGD is set as the low flow limit that can occur in mid-summer at 

3:00am..

Based on the results of the Pilot Study, Warren should be able to accept brine water at the initial 

rate of 100,000 gallons per day at a concentration of 50,000 mg/l TDS (41,700 lbs. TDS) and 

increase flow at a controlled rate, while sampling, to determine final ceiling concentration.

The Pilot Study was completed in April of 2010 and the report provided to OEPA by May of 

2010. OEPA did not issue a modified NPDES to Warren to allow for treatment of flowback brine 

until December of 2010.

Daily Processing

Ohio’s whole model for the treatment of low TDS flowback brine wastewater is based on the 

observance of issues that was witnessed during 2009 through 2010 by treatment plants that was 

processing brine wastewater in Pennsylvania. The following matrix highlights the differences 

between Pennsylvania and Ohio for acceptance and treatment of Hydraulic Fracturing 

Wastewater Treatment:
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-32

Pennsylvania had been accepting Oil & Gas Well Industry brine water since approximately 1984. 

This initial water was not from the Marcellus Shale Play but from traditional vertical drilling 

processes where hydraulic fracturing was not being used. Some of this early process water was 

being discharged into local municipal wastewater treatment facilities. 

The practice continued throughout the 80’s, 90’s and early part of 2000 without incident, 

oversight or concern. When the boom occurred on the Marcellus Shale Play in 2008, the volume 

of brine water that needed to be disposed of increased significantly. As a result of this increase, 

35 municipal wastewater treatment plants began directly accepting brine water. Because of over 

20 years of practice accepting brine water without incident, no limits on volume or pollutants 

were set and no additional testing requirements were initiated. The practices that were employed 

were:

Direct discharge to the municipal wastewater treatment facility.

No limit set on volume of brine water being discharged.

No limit set on total suspended solids (TDS) in the brine water.

No screening of the brine water for heavy metals, radiation, organic or volatile compounds.

No toxicity testing on combined flow discharge.

No baseline testing initiated to determine facility of receiving stream current levels of 

pollutants.

Ohio’s approach was completely different. In 1985, USEPA mandated the requirement of 

Industrial Pretreatment. Prior to 1985, large amounts of heavy metals, volatile and organic 

compounds were routinely discharged into a municipal wastewater facility. The mandate for 

pretreatment required an industry to develop treatment practices that removed pollution of 

concern at the point source to a level that was set through federal categorical and local limits. 

These limits were designed to allow a municipal treatment facility to safely discharge wastewater 

into a receiving stream with pollutant concentrations at or below acceptable levels. The 

implementation of this procedure substantially improved water quality.

This is the method that Ohio employed for the handling of brine water. Ohio initiated the 8 week, 

live process, pilot study to determine the feasibility of brine water treatment. The pilot study led 

to the treatment practices as follows:

Only Flowback, muddy and brackish brine water will be allowed for treatment. No Produced water 

will be allowed.

Direct discharge to a municipal wastewater treatment plant will not be allowed. Brine water must 

go to a centralized waste treatment facility (CWF) for pretreatment prior to discharging to a 

municipal wastewater treatment facility (MWTF). The CWF will remove heavy metals, suspended 

solids and other pollutants to categorical and local limits and adjust pH prior to discharge.

Pennsylvania Ohio

Direct discharge to the municipal wastewater treatment facility Direct discharge to a municipal wastewater treatment plant will not be allowed

No limit set on volume of brine water being discharged A limit will be set on the total volume of brine water that can be treated daily

No limit set on total suspended solids (TDS) in the brine water A limit of no greater than 50,000 mg/l of TDS in the flow will be allowed 

No testing of the brine water All brine water will be regularly tested 

No toxicity testing on combined flow discharge Quarterly toxicity testing will be accomplished 

No baseline testing initiated Baseline levels will be established
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-33

A limit will be set on the total volume of brine water that can be treated daily. This limit will be 

established based on the ability of the treatment facility to assimilate without toxic conditions or 

water quality conditions occurring.

A limit of no greater than 50,000 mg/l of TDS in the flow will be allowed to be discharged from 

the CWF into the MWTF.

All brine water will be regularly tested for heavy metals, radiation and volatile compounds and 

will be summarized in a daily operational report.

Quarterly toxicity testing will be accomplished by the MWTF. 

Ohio’s method uses the time proven technique of centralized point source pretreatment with 

structured limits and testing requirements where Pennsylvania’s method basically had no 

controls at all. 

In October of 2010, OEPA issued a PTI to Patriot Water Treatment LLC to install and operate a 

centralized waste treatment facility for brine water treatment. In September of 2010, OEPA 

issued a draft NPDES modification to Warren that would allow for the acceptance and treatment 

of low TDS flowback brine wastewater from a CWF. The limits set did not take into 

consideration the data accumulated from the Pilot Study and appeared to be an arbitrary number 

set by the confines of the final limits used in the Pilot Study; 100,000 gallons per day at a 

concentration of 50,000 mg/l. However, the Pilot Study did not run for a full 24 hr. day but was 

constrained to the hours when Warren management was on site. This resulted in an 8 hour “day.” 

Therefore the Pilot Study had clearly demonstrated that Warren could accept 300,000 gallons of 

flowback brine at a concentration of 50,000 mg/l TDS during a 24 hr. period without upset to the 

plant or receiving stream. 

This was pointed out to OEPA in a series of letters between the months of September –

December 2010. Another issue of concern was that while the NPDES permit was limiting the 

volume of flowback brine that could be treated to 100,000 gallons at 50,000 mg/l TDS, the 

restriction was based on gallons accepted not pounds of pollutant received. 

The fundamental problem with this is the discharge limit of 100,000 gallons per day had no 

referential scientific or reasonable basis. If a finite number was being assigned to a facility, the 

number should be pounds applied not volume. OEPA did not accept these concerns and without 

explanation, issued a final NPDES permit revision on December 1, 2010 to allow the POTW to 

accept brine waste water generated during oil and gas well drilling, development and production. 

The brine waste water must be discharged from a Centralized Waste Treatment (CWT) facility. 

The waste water discharged from a CWT to the Warren POTW had the limitations set at a total 

acceptance of 100,000 gallons of flowback brine per day at a maximum concentration of 50,000 

mg/l TDS.

TDS levels in the receiving stream would be a major concern to the overall acceptance and 

success of the treatment model. Warren’s receiving stream, the Mahoning River, flowed into 

Pennsylvania where the state had recently enacted new in-stream TDS limitations. These 

limitations required OEPA to ensure that river levels at the Ohio/PA border remain at or below 

500 mg/l TDS. Realizing that the overall success of this program depended on how TDS would 

impact river quality, Warren initiated a self-imposed river sampling program that monitored TDS 

levels throughout the watershed. The initial program sampled locations upstream and 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-34

downstream of New Castle, PA, a community just across the state border that was receiving gas 

& oil well brine water for treatment at their Wastewater Plant which discharged into the 

Mahoning River and locations on the Shenango River which flowed immediately east of New 

Castle and joined with the Mahoning south of the community to form the Beaver River. This 

sampling program was initiated on November 1, 2010 before OEPA had even issued Warren the 

NPDES modification to allow for brine water treatment.

Additional locations upstream and downstream of Warren were added to better model point and 

non-point source river levels throughout the watershed. Over the course of the last two years, 

more locations were added that extended into PA and eventually down to the Ohio River which 

the Beaver River is tributary to. A total of 8 locations were finally part of the sampling regiment. 

This allowed for a more complete modeling of the watershed. Initially only TDS was being 

analyzed as a whole but we began to analyze for both Chlorides and Sulfides to better develop 

origination sources of the TDS. Pennsylvania has a very developed and active Mining Industry 

that contributes to the overall load of TDS in the rivers. The dominant dissolved mineral from 

this activity would be Sulfides whereas Chlorides would constitute the majority of dissolved 

solid from oil & gas brine waste.

In May of 2010 we began to analyze for Bromide when it was determined that it was a potential 

pollutant of concern from oil & gas brine wastewater due to the development of Trihalomethanes 

in the presence of Chlorine in drinking water treatment facilities. All of these testing regimens 

are self-imposed and not required by OEPA. All sampling is conducted once a week by our 

Industrial Pre-treatment Coordinator. With the monitoring protocol in place Warren began 

accepting 100,000 gallons per day of pre-treated flowback brine water with a maximum 

concentration of 50,000 mg/l TDS from Patriot Water Treatment LLC on December 27, 2010. 

This process has continued to date uninterrupted except for a 3 month period in 2012 when 

OEPA issued a new NPDES Permit that removed Warren’s ability to accept brine water.

In December 2010, Warren filed an appeal with the Environmental Review Appeals Commission 

(ERAC) to the NPDES modification challenging the 100,000 gallon per day limit as the 

controlling parameter. In May of 2011, OEPA issued a letter to the Ohio Department of Natural 

Resources (ODNR) indicating that the permits issued to Warren and Patriot were in violation of 

ORC 1509.22 and would not renew the modification when Warren’s current permit expired on 

December 31, 2011. This resulted in a legal battle that raged for the remaining part of 2011 but at 

no time did either OEPA or ODNR issue an order to Warren or Patriot to stop treatment. During 

the next year and 4 months, Warren continued to accept pre-treated brine water from Patriot 

without any plant or receiving stream violations or upsets. OEPA did not issue a new NPDES to 

Warren until April 1, 2012 where OEPA inserted a new Section BB that stated:

Beginning on the effective date of this permit, the permittee shall stop accepting brine 

wastewater from oil or gas drilling, exploration or production. Disposal of brine 

wastewater from oil or gas drilling, exploration or production through a wastewater 

treatment plant and discharge to waters of the state is not an authorized method of 

disposal under R.C. 1509.22(C)(1) unless and until it is approved by the Chief of the 

Division of Oil and Gas Resources Management for testing or implementing a new 

technology or method of disposal. If such an approval is granted under R.C. 

1509.22(C)(1) by the Chief of the Division of Oil and Gas Resources Management, the 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-35

permittee must submit an NPDES Permit Modification application to Ohio EPA for 

approval prior to acceptance of brine wastewater. The permittee may not accept brine 

wastewater from oil or gas drilling, exploration or production until after an NPDES 

Permit Modification authorizing acceptance of the material is approved.

This caused Warren to order Patriot to cease discharging brine water to its Municipal 

Wastewater Plant effectively shutting down Patriot. Warren immediately appealed the 

new NPDES to ERAC and asked them to enjoin it with the existing appeal. ERAC denied 

the enjoinment based on the previous appeal was for a modification that did not exist and 

rendered the appeal mote, but allowed the appeal of the new permit to be placed into 

proceeding schedules already established for the previous appeal. This allowed a hearing 

on the new NPDES permit to begin in April of 2012 and was completed in early May of 

2012. On July 3, 2012 ERAC determined that Section II, BB of the 2012 Warren NPDES 

was both unlawful and unreasonable. In so holding, ERAC unilaterally modified 

Warren’s NPDES to remove Section II, BB in its entirety. ERAC also upheld Patriot’s 

2010 PTI which contained an express provision allowing Patriot to send oil and gas 

waters to Warren. Warren issued a letter to Patriot to start up operations in July of 2012 

and Warren has continued to receive daily discharges from Patriot since that time without 

a single water quality violation or facility upset. 

On September 12, 2011 through September 16, 2011, USEPA Region 5 conducted a compliance 

inspection to determine that the Warren WPCC was only accepting brine waste water generated 

from the oil and gas industry from one CWT facility (Patriot), and that the POTW had not 

experienced any of the following conditions since accepting the brine waste water: 

1. Diminished or inhibited performance of the biological treatment processes, 

2. Adverse impacts to the downstream water quality, 

3. Adverse impacts to the quality of the facility’s biosolids. 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-36

Both Warren and Patriot were inspected and numerous tests were conducted. Overall, 

approximately 950 pages of documents were generated from the report. A summary of the key 

constituents of concern is shown below:

In addition to a complete metals analysis, radiological screening was accomplished. The 

inspection included sampling of the influent and effluent at the Warren POTW and Patriot and 

sludge press samples from Patriot and Warren were analyzed for RCRA levels. The report 

concluded that all sampling indicated the discharge for Warren’s POTW was in compliance with 

the NPDES permit limitations for Final Outfall – 001and that none of the sludge sample results 

were above the RCRA Regulatory Toxicity Levels. 

Daily Processing Summary

`The waste treatment model used in Warren has almost 2 1⁄2 years of operational data that 

demonstrates that it is a safe and viable alternative disposal that compliments other disposal 

options including deep well injection. The model requires both a CWT and a POTW. It requires 

extensive testing by both entities which are mandated and voluntary. It only allows for a small 

percentage of hydraulic fracturing wastewater to be accepted. The water that this model accepts; 

low TDS, pit, flowback, muddy and storm waters are also the waters that are most problematic 

for deep well injection.

Not all POTWs will be able to develop a program that will allow this model to be implemented. 

A POTW must have dilution capacity, historical low TDS influent levels, receiving stream 

assimilation capacity and a very capable Pretreatment Program. It must also be willing to submit 

itself to mandatory and voluntary testing beyond typical NPDES requirements. While this model 

uses dilution as a control mechanism, it is the same mechanism currently used to handle like 

waste loads for other industrial sources such as Steel Mills, Food Processing Facilities, 

Pharmaceutical manufactures, paper producers and other high TDS dischargers. None of these 

industrial flows are fully treated in a conventional POTW.

Properly implemented, this model can become a catalyst for enhanced TDS treatment that all 

other industries could benefit from. Enhanced treatment technologies are available but are 

currently very costly to implement and operate. Working in partnership with the private sector, 

this model can be a bridge to better treatment. As has already occurred in other industrial

treatment areas, this model provides a revenue stream that can support research and 

development. Developing programs with targeted goals for waste load reduction over a 

determined timeline can create the synergy necessary to achieve enhanced waste recovery 

systems that will be economical to install and operate.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-37

Reducing Fresh Water Use in Upstream Oil and Gas Hydraulic Fracturing

Michael Dunkel

Pioneer Natural Resources USA, Inc.

The statements made during the workshop do not represent the views or opinions of EPA.

The claims made by participants have not been verified or endorsed by EPA.

Hydraulic fracturing (HF) uses water as a carrier fluid for the sand or ceramic that props open the 

fractures. Typically, fresh groundwater or fresh surface water is used as a source of this water. 

Pioneer Natural Resources embarked on a multi-year initiative to conserve fresh water by 

reducing its use in HF.

Key definitions of water types include:

1. Fresh water – surface or ground water with total dissolved solids (TDS) less than 1,000 

milligrams per liter (mg/l)

2. Produced water – naturally occurring water that is produced with the oil and gas and is 

normally high in TDS. This includes the initial water production that is occasionally 

referred to as flowback water.

3. Brackish Water – naturally occurring groundwater with TDS greater than 1,000 mg/l (not 

from an oil and gas reservoir)

The primary components of the study address:

1. Water quality needed for HF if using treated produced water or blended water

2. Water treatment technologies currently available that effectively treat produced water for 

reuse or recycling

3. Logistics of transporting produced water from its source to treatment site and on to the 

well for HF

4. Economics and environmental aspects of storing, transporting and treating water

5. Naturally occurring brackish water as a substitute for fresh water

6. Prevention of evaporation from storage 

The variable natural of the formation rock and formation fluids requires different technical and 

economic solutions to conserve fresh water. This abstract evaluates some of the factors 

impacting HF and the potential solutions.

Water quality needed for HF

A third-party consultant was contracted to study the types of waters being used, types of fracture 

treatments being performed and possible fresh or brackish waters which could be used with 

treated produced water for three areas operated by Pioneer in Texas. The type of fracture design 

may dictate the quality of the water needed for the fracture fluid. For example, hydraulic 

fracturing technologies can vary between slickwater (mostly water-like fluid) and gels (fluids 

that create a gel-based fluid that holds the proppant.

The three areas used a variety of hydraulic fracturing designs, had varying water qualities that 

included higher concentrations of some naturally occurring minerals than optimal for the HF 

design. The solutions for all of the areas included removal of the total suspended solids (TSS). 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-38

The individual minerals needed to be addressed in some cases before the water could be re-used 

effectively.

The overall conclusion is water treatment levels need to be evaluated based on specific hydraulic 

fracturing design and available water quality. None of the recommended solutions require 

removing total dissolved solids (TDS) to replicate “fresh” water. The optimal solution may vary 

within a state or even within the basin or field.

Water treatment technologies

Pioneer has tabulated over 100 companies marketing water management and water treatment 

technologies. The technologies are generally established methods applied for use in water 

treatment operations which can be applied to oil field applications. Some technologies/systems 

include electrocoagulation (EC), flocculation, membrane filtration, chemical treatments and 

evaporative/distillation systems.

Pioneer tested the technologies employed by twelve companies during 2011 and 2012. Six of the 

representative pilot treatment results are shown in Table 1 below. The companies’ names and 

certain identifying factors are hidden for confidentiality purposes. This data demonstrates most 

technologies removed some analytes, but effectiveness varied significantly. The red highlighted 

cells indicate effluent did not meet Pioneer’s requirements for use in a HF application, while the 

green highlighted cells indicate treatment results were sufficient for HF use.

Analyte guidelines are set to prevent interference with hydraulic fracturing gels. This table 

suggests quality control of water treatment is difficult and variable. TSS, the most significant 

component, had observed reductions of 44% to 98% from influent TSS.

Ceramic Coated MembraneUltrafiltration, 

Chemical, 

Forward Osmosis

Ultrafiltration, 

Chemical

ElectrocoagulationReverse 

Osmosis, 

Nanofiltration

ElectrocoagulationElectrocoagulation

Constituent Units

Avg. Change Inf 

to Eff

Avg. Change Inf 

to Eff

Avg. Change 

Inf to Eff

Avg. Change 

Inf to Eff

Avg. Change 

Inf to Eff

Avg. 

Change Inf 

Avg. Change 

Inf to Eff

Barium mg/L 9% -27% -92% -9% -86% 217% -7%

Boron mg/L 8% -15% -54% -4% -25% 3% -12%

Calcium mg/L 20% -12% -97% 1% -79% 58% -8%

Chloride mg/L -4% 63% -38% -4% -28% 42% -5%

Iron mg/L -24% -44% -100% 71% -98% -100% -100% Magnesium mg/L 18% -22% -44% 2% -92% 45% -8%

Oil & Grease HEM mg/L -87% -83% 0% 48% 0% 0% -100%

SiO2, Silica mg/L 2% -19% -80% -5% -45% -72% -84%

Sodium mg/L 19% 64% -4% 0% -24% 38% -1%

Strontium mg/L 2% -15% -81% 3% -85% 140% -5%

Sulfate mg/L -15% 148% 33% -30% 426% -10% -18%

Total Dissolved Solids mg/L 0% 46% -28% -3% -51% 58% 17%

Total Suspended Solids mg/L -48% -44% -93% 113% -98% -81% -49%

Treatment Passed PXD Guidelines

Treatment Failed PXD Guidelines

Table 1. Water Technologies Tested during 2011 and 2012.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-39

Figure 1. Electrocoagulation unit Figure 2. Membrane Unit

Logistics of transporting produced water

Logistics of transporting and storing produced water is a significant portion of operations of

water recycling in oil and gas operations. In a typical centralized treatment scenario, produced 

water must first be gathered from individual wells or to the centralized location where treatment 

occurs. Gathering water to a central location allows a critical mass which often translates to

lower treatment costs. However, additional collection lines must be installed before recycling 

may commence. Alternatively, trucking of produced water is often employed for smaller 

volumes of water.

Once produced water is collected at a central site, treatment should immediately commence, so 

this water can be stored and available for immediate reuse. Typically, the HF process requires 

water at high rates and may use a majority of stored water in a short time. Often, temporary lines 

are used to transport treated produced water from central storage to a new well to be fractured. 

Produced water requires lines which do not leak, but can also be easily installed and moved to a

new site at the end of HF treatment.

Economics and environmental aspects

Economics of recycling produced water in oil and gas operations are highly variable depend on:

1. Quality of water needed for planned HF design, 

2. Quality of produced water, 

3. Concentration of planned new HF wells to nearby produced water, and 

4. Availability/accessibility to water disposal wells. 

Typically, based on an available volume of water, produced water must first be accumulated in a 

central site where it can be treated. Small volumes of water are generally very expensive to treat; 

thus the desire to accumulate larger volumes in a central location makes sense. Often, additional 

water pipelines are needed to transport produced water to a central location. Capital cost 

increases with increasing distance and size of the pipeline, and can be highly variable. Whereas, 

operating cost of the pipeline is usually minimal. Alternatively, produced water can be trucked 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-40

to a central site for treatment. Trucking costs may range from $1 to $3 per barrel depending on 

local conditions and distance transported.

At a central site, produced water may be treated by a variety of technologies designed to remove

bacteria, eliminate any residual hydrocarbons and suspended solids, reduce potential scaling (a 

solid precipitation when minerals combine) caused by mixing different types of water, and, in 

some cases, removal of the majority of minerals through desalination. The type of fracture 

design may dictate the quality of water needed for fracture fluid. For example, hydraulic 

fracturing technologies can vary between slickwater (mostly water-like fluid) and gels (fluids 

under certain temperatures, pressures and chemical combinations, create a gel-based fluid that 

holds the proppant). The volume of water processed per day highly influences the cost to treat 

produced water to usable levels. This is partly due to a need to have operating personnel on 

location for water treatment. This effectively limits minimal volume of daily throughput for 

recycling to be economically viable to thousands of barrels of water per day; which can be the 

production from 10’s to 100’s wells. This reinforces why the accumulating phase of this process 

is so important. Treatment cost for minimal water treatment (not desalination) may range from 

$2 per barrel for high volumes to multiples of $2 per barrel for smaller volumes of water (which 

is more common). To desalinate produced water to a drinking water standard, costs may vary 

from $4 to multiples of $4 per barrel depending on the volume per day and the quality of inlet 

water being treated.

Once produced water is treated, it needs to be stored in tanks or a pond. An earthen pond is often 

more practical than having a large number of tanks. For saline water storage, water ponds often 

have more stringent construction criteria to assure safe storage of more environmentally sensitive 

water. The saline water ponds may cost $500,000 to an order of magnitude higher, compared to 

one third to one tenth for an equivalent sized storage designed for fresh water.

The last stage of the recycling process is to transport treated produced water from a central 

storage area to a HF site. Transportation of water is normally accomplished with a temporary 

no-leak line to the HF site which can stretch to five or more miles. Landowner approval is 

required and would typically include a payment for temporary access which could last two to 

four weeks. Because recycling involves produced water, the pipeline cost is typically twice the 

cost of fresh water pipeline transport.

An economic decision to recycle produced water is often driven by the cost of a next best 

alternative, which is typically disposal into a class 2 injection well. The cost of trucking water to 

a disposal well and the cost of disposing of fluid into a class 2 well vary depending on regional 

geology, availability of roads and the distance involved in trucking. Trucking and disposal costs 

may range from $1 per barrel of water to an order of magnitude higher in various parts of the 

United States.

Environmental factors, such as availability of water for HF, are very important in consideration 

for recycling produced water. If water is limited in an area, a company may decide to recycle 

produced water for strategic reasons, even if it costs more than sourcing fresh water. Additional 

environmental factors may need to be considered if recycling involves increased environmental 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-41

exposure due to the storage or transport of produced water. Often, additional environmental risk 

can be mitigated by higher design standards and practices.

Naturally occurring brackish water as a substitute for fresh water

In some areas where HF is being employed, recycling produced water is significantly more 

costly than disposal of produced water into class 2 injection wells. In an effort to conserve fresh 

water, naturally occurring brackish water is sourced. Brackish water is generally defined as 

groundwater, not produced water, from an oil or gas reservoir, having a concentration of total 

dissolved solids (TDS) over 1,000 milligrams per liter (mg/l). Brackish water can be used 

directly for HF source water, in some cases. Although sometimes, it is blended with fresh water 

depending on the HF design and water quality.

Brackish water is not found everywhere. Usually brackish water is found deeper than fresh 

groundwater, and often produces at lower rates than shallower fresh groundwater. Because of 

these factors, brackish water may be more costly to source than fresh groundwater. The oil and 

gas industry has significantly increased use of brackish water in Texasi.

Estimated at more than 2.7 billion acre-feet, brackish groundwater constitutes an important water 

supply option in Texasii. “Much of the water in the state’s aquifers is fresh; however, brackish 

groundwater is more common than fresh groundwater in the southern Gulf Coast area and in 

large parts of West Texasiii.” 

Prevention of evaporation from storage

Large numbers of water storage ponds are used for HF operations. The majority of water in 

Texas is fresh water stored in lined ponds to prevent leakage/loss. In hot dry climates, 

evaporation from water storage can be significant. The Texas Water Development Board 

(TWDB) estimates evaporation by county by month in Texasiv. 

Pioneer verified the evaporation rate in North Texas in July 2012 and found good agreement 

with the data on the TWDB website. Figure 4 shows the primitive, yet effective, evaporation 

testing bucket. Figure 5 is an installed pond cover in west Texas with a pump to move rainwater 

from above the cover to below the cover in an attempt to reduce/eliminate evaporation of water.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-42

Figure 3. Testing a pond for evaporation Figure 4. Pond Cover over freshwater storage

Subsequent economic evaluation indicates that the potential cost of covering a water pond may 

save enough water in some cases to pay back the cost of covering it. Cost of water and estimated 

life of the storage pond are significant inputs to the results. Operationally, the covers must float 

on the surface and have a method to prevent water, including rain, from accumulating on top of 

the cover. Pond covers must also be durable enough to withstand high winds and provide a 

practical operational solution. Assuming an operational and economic solution is found, current 

thinking indicates that storage covers may become one component in the effort to conserve fresh 

water. 

Conclusions

Oil and gas uses a significant volume of water for HF. Until recently, the vast majority of water 

utilized for HF activities has been fresh surface water and fresh groundwater. The variable 

natural of the formation rock and formation fluids requires different technical and economic 

solutions to conserve fresh water. Although the most practical solutions to vary by region, the 

oil and gas industry is making strides to reduce fresh water consumption by reusing/recycling 

produced water, sourcing brackish water and preventing evaporation.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-43

References

 

i Nicot, Jean-Philippe, P.E., P.G., Reedy, Robert C., P.G., Costley, Ruth A., and P.E. Huang, Yun 

(2012) Oil & Gas Water Use in Texas: Update to the 2011 Mining Water Use Report

prepared for Texas Oil & Gas Association, Bureau of Economic Geology, The University of 

Texas at Austin.

ii Texas Water Development Board (2012) Brackish Resources Aquifer Characterization System 

(BRACS) funded by the 81st Texas Legislature, 2009.

iii George, Peter G., Ph.D., P.G., Mace, Robert E, Ph.D., P.G. and Petrossian, Rima, P.G., (2011) 

Aquifers of Texas, Report 380 for the Texas Water Development Board.

iv Texas Water Development Board and the National Weather Service data collected from 1954 

through 2011. Precipitation & Evaporation (2012)
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-44

Treatment for the Beneficial Reuse of Produced Water and 

Hydraulic Fracturing Flowback Water

David R. Stewart

Energy Water Solutions, LLC

The statements made during the workshop do not represent the views or opinions of the EPA.

The claims made by the participants have not been verified or endorsed by the EPA.

Introduction

Reuse of produced water and hydraulic flowback water will be a significant issue as the United 

States develops its oil and gas shale plays. Water is an essential component of the development 

of oil and gas wells, both in the development of the well and through the increased use of 

hydraulic fracturing techniques. Well development typically utilizes 60,000 to 650,000 gallons of 

water for the use of cuttings control and lubrication of the drill bit. Currently, 3 to 5 million 

gallons of water are utilized per hydraulic fracturing event per well.8 One issue is the source of

this water and its impact on the environment. The Colorado Division of Water Resources, 

Colorado Water Conservation Board, and the Colorado Oil and Gas Conservation Commission 

did a study on the amount of water used by energy companies. This amount was shown to be 

0.14–0.8 percent of the annual flow of water in Colorado.5 However, this would be close to what 

the City of Denver would use in 6 to 12 months. So, while this is a small percentage, it is a large 

volume of water, especially in drought conditions.

Several exploration and production (E&P) companies are embracing water reuse and recycling as 

part of their overall corporate structure.6 Energy companies that wish to conserve and reuse 

water will require methods of wastewater treatment developed to allow for reuse and recycling. 

This paper discusses the water treatment facilities we have developed for produced and flowback 

water and what considerations are important in the feasibility of this water reuse opportunity.

To discuss the reuse of produced water or hydraulic fracturing fluids, we must first define these 

terms. Produced water is the water that originates in an oil or gas well and is developed with the 

oil and/or gas resource. Hydraulic fracturing flowback (flowback) water is defined as the water 

that is released from the well after a hydraulic fracturing process. This flowback water normally 

will return between 50 to 80 percent of the water that was originally used in the hydraulic 

fracturing process and is returned over a 60- to 90-day period. Produced water will follow the 

flowback water after the initial 60- to 90-day period. Therefore, if 5 million gallons are used in 

the hydraulic fracturing process, then 2.5 to 4 million gallons will be returned as flowback water.

Another important issue in the reuse of produced and flowback water is water quality. Water 

quality is important due to the components of the produced or flowback water and the interaction 

of these components with either the hydraulic fracturing fluids or the formation water. In 

addition, water quality determines the ability to treat and eventually discharge produced or 

flowback water to the surface. The regulations that affect these water quality components are 

also discussed. However, E&P companies need to be aware that the compounds used in their 

 

8 Matthew E. Mantell, “Produced Water Reuse and Recycling Challenges and Opportunities Across Major Shale 

Plays,” Chesapeake Energy Corporation, March 29, 2011.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-45

operation can add to issues in treatment; therefore, any component added to their exploration 

fluids should be evaluated for its removal in wastewater treatment.

Water Quality

Produced and flowback water include water naturally occurring alongside hydrocarbon deposits 

as well as constituents injected into the formation. The following are the main contaminants of 

concern in produced and flowback water:7

Total dissolved solids (TDS), ranging from brackish water (>1,000 mg/l) to saturation 

levels (>300,000 mg/l)

Oil and grease

Suspended solids

Dispersed oil

Dissolved and volatile organic compounds (VOCs)

Heavy metals

Radionuclides

Dissolved gases and bacteria

Chemical additives, such as biocides, scale and corrosion inhibitors, guar gum, and 

emulsion/reverse-emulsion breakers

The amounts of these constituents vary considerably from the formation water to the mixture of 

chemical additives.8In the early development of the production well there will be higher 

concentrations of the chemical additives, and later in the well development the produced water 

will be closer to the formation water. A more detailed listing of the typical flowback water 

chemical additives is found in Attachment A.9

Facilities for the Beneficial Reuse of Produced Water and Hydraulic Flowback Water

One of the first facilities constructed for the beneficial use of produced water was conceived in 

2001 and constructed in 2005. The Wellington Water Works Produced Water Treatment Facility 

in northern Colorado, with a capacity of 5,000 bbl/day, has operated continuously since 2006 

and has provided water for agricultural use, hydraulic fracturing makeup water, and municipal 

drinking water supply augmentation. This facility is dedicated to the Wellington Oil field. 

A similar facility was developed for Harley Dome 1, LLC in Westwater, Utah. This facility is 

slated to start operation in June 2013 and has a capacity of 5,000 bbl/day with the potential to 

increase to 15,000 bbl/day. The facility is designed to discharge water to the Colorado River 

system but likely will sell most of the water as hydraulic fracturing makeup water.

We have worked on the design of treatment facilities for tight gas sand in Wyoming, coal bed 

methane (CBM) facilities in Wyoming and Colorado, and also oil production facilities in the 

Eagleford Field in Texas. All of these facilities have several common concepts for treatment.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-46

Impacts on the Water Market

Sixteen energy-related constituents (energy companies, federal and state agencies, academia, 

environmental NGOs) were surveyed regarding hydraulic fracturing operations.10 The top 

concerns from this survey were (1) water availability, (2) truck traffic, (3) surface spills and 

leaks, and (4) air pollution. These are the same issues identified by the EPA in their hydraulic 

fracturing studies. All of these issues can be resolved with proper water reuse facility treatment 

methods. 

Treatment Issues

In the past, most companies have either used fresh water or a blend of produced water and fresh 

water with limited treatment. However, the growing need or desire for a higher percentage of 

water for reuse or recycling necessitates higher levels of treatment. The areas that need to be 

considered are as follows: (1) the final use of the water, (2) difficult treatment issues, (3) 

chemicals used in hydraulic fracturing, (4) air pollution issues, (5) brine disposal, and (6) 

potential for harvesting of elements from water.

1.0 Final Use of the Produced Water or Hydraulic Flowback Water

There are several areas that will 

fit into the recycling or reuse of 

produced water or hydraulic 

flowback water. These include 

(1) makeup water for hydraulic 

fracturing fluid, (2) stream 

discharge of the water, and (3) 

augmentation of municipal water 

supplies. A good summary of 

this type of treatment evaluation 

is found in Figure 1. This chart 

indicates the type of treatment 

required for the removal of 

various constituents.

Makeup Water for Hydraulic 

Fracturing Fluid

An excellent reference for 

makeup water treatment and 

criteria is found in Attachment 

B, the PTAC Water Decision 

Tree.11 As noted on the chart, the 

items that need to be controlled are bacteria, scale formers, iron, corrosion parameters, and total 

dissolved solids. As long as these items are addressed, you can normally provide chemistry for 

the hydraulic fracturing fluid makeup to allow for successful operation.

Figure 1. Treatment Requirements
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-47

Water Discharge to Surface Water or Groundwater

Water reuse for either agricultural or municipal water augmentation will require discharge to a 

surface water or tributary groundwater, which will require a discharge permit. Under 40 CFR 

435, the EPA is allowed to regulate the discharge of wastewater from E&P operations under the 

Clean Water Act for industrial pretreatment categorical dischargers. However, currently the EPA 

only regulates discharge of produced water from offshore platforms. In 2010, Mr. Carry 

Johnston, of the EPA, investigated the potential for this regulation in the control of CBM waters. 

However, at this point, it appears to be a low priority for the agency.12 We worked with the State 

of Colorado to develop a statewide permit system for the discharge of produced water or 

hydraulic flowback water. The statewide permit allows for the discharge of water with a known 

discharge value from a treatment facility. The compliance point is at the point of discharge and 

therefore in-stream mixing is not allowed as part of the permitted process. The time line for 

obtaining this type of permit is approximately 2 months. In particular, the sodium absorption 

ratio (SAR, the ratio of sodium to calcium and magnesium) is typically below a value of 3, 

which will require the control of sodium in the discharge. The other items of concern are 

typically metals and some organics. In addition, the discharge needs to meet the Toxicity 

Effluent Limits testing protocol. However, if the discharge is controlled for SAR, then meeting 

the toxicity limits is normally not an issue.

2.0 Difficult Treatment Constituents

We break the area of difficult treatment constituents into two areas: organics and inorganics. In 

the organic area, we have found that waters containing asphaltines, heavy oils, and paraffins 

require a special treatment process. The inorganics are normally controlled through the use of 

membrane filtration. 

Organic Treatment Techniques

The organics are classified in two types. The first type is volatile organic compounds (VOCs). 

The VOCs are normally determined by benzene, toluene, ethyl-benzene, and xylene (BTEX). Of 

these compounds, the most difficult to treat for is benzene, due to the discharge limit of 0.001 

mg/l. The techniques of air stripping and activated carbon adsorption have worked well at the 

Wellington facility.

The second type, the heavy organics such as the asphaltines, is removed utilizing a walnut shell 

filter (WSF). This is a process that is typical to the oil fields and has been used for decades. If 

there is any type of membrane treatment in the process, it is necessary to remove these heavy 

organics prior to treatment.

One of the most significant issues in the reuse of 

produced water and especially flowback water is guar 

gum. The values that we have seen in the field range 

from 100 mg/l to over 20,000 mg/l of guar gum. 

Guar gum is a thixotrophic material that is used to 

move the silica sand or proppant to the end of the 

Figure 2. Guar Compound
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-48

fracture zone. This material is a significant hindrance to any filtration of this water. 

Treatment of the guar gum, which is a natural polymer, will require either a breakdown of the 

polymer by enzyme chemistry or a reaction of the polymer with a cation, such as iron. Therefore 

it is extremely important to understand the levels of guar gum in the flowback water, how these 

different concentrations react to filtration, and to be able to test for this chemical additive in the 

field as well as the laboratory.

The control of microorganisms is also very important. Microorganisms can be abundant (more 

than 1 x 109organisms per 100 ml) in produced water, depending on the formation. It is very 

important when considering reuse to control sulfate-reducing bacteria. 

Inorganic Treatment Techniques

Inorganic treatment is typically controlled by precipitation chemistry. The use of ion exchange 

for this type of treatment is normally not used due to the brine stream that is created. The 

exception is the use of the Higgins Loop technology in CBM waters. This has been used 

extensively in the Powder River basin area of Wyoming and Montana. However, it normally 

requires a water in which the majority of the TDS is in the form of carbonates. In the areas that 

we have been involved in, we have found that the produced water is normally sodium chloride–

laden water. The Higgins Loop is not useful for this type of water.13

We have found that the most useful treatment for inorganics is precipitation chemistry followed 

by ceramic microfiltration (CMF) and then either nanofiltration (NF) or reverse osmosis (RO). 

The precipitation chemistry can be performed utilizing the adjustment of pH and solubility or can 

also be accomplished by electrocoagulation (EC). Due to the concern of handling solids in the 

facility, the lowest pH possible to meet the NF/RO feed water criteria for precipitation is desired. 

This can normally be accomplished with the use of EC.

3.0 Overall Treatment Process

With the constraints identified above, we have developed the following treatment process 

stream:

VOC removal with air stripping

Oil/heavy organic removal with WSF

Precipitation chemistry utilizing EC

Removal of precipitated multivalent ions utilizing CMF

Removal of remaining VOCs with activated carbon

Monovalent ion removal utilizing NF/RO
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-49

Figure 3. EWS Treatment Process

The flowchart in Attachment B provides the criteria for which water quality parameters need to 

be examined and also provides the type of treatment required. The areas that we have found to be 

critical for reuse of water in hydraulic fracturing are:

pH

Boron

Barium

Iron

Calcium

Magnesium

Silica

Strontium

These parameters will determine the chemistry precipitation and also address the scale-formation 

chemicals. 

The other issue of concern is the scale-formation chemistry. As shown in Table 1, there are 

significant scale-formation constituents. These include barium sulfate, silicates, calcium, and 

magnesium. Therefore, if reuse is a consideration, the constituents that could form scales in the 

formation need to be removed so as not to impact the production well.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-50

Table 1. Scale Formation Concerns

In addition to the above issues, it is important to consider which compounds can lead to 

interference issues with the hydraulic fracturing chemistry. An example of this is boron, which is 

an accelerant of the fracturing fluids. Therefore, the boron concentration must be below 1 mg/l in 

the hydraulic fracturing fluid makeup water.

These three components—guar gum, scale-forming chemistry, and hydraulic fracturing chemical 

accelerants—are difficult items to remove and will be a challenge as the industry moves forward 

with water recycling and reuse. An example of the water quality goals for hydraulic fracturing 

fluid makeup water is provided in Table 2.

Table 2. Water Quality Goals for Hydraulic Fracturing Fluids

Bacteria 100,000 per 100 ml

Barium (mg/l) < 2

Bicarbonates (mg/l) 250 to 100,000

Calcium (mg/l) 300

Chlorides (mg/l) 2,000 to 40,000

Iron (mg/l) 10

Hydrogen sulfide (mg/l) ND

Magnesium (mg/l) 100

pH 6.5 to 8.0

Phosphates (mg/l) 10

Radionuclides (pCi/l) <15

Reducing agents (mg/l) ND

Silica (mg/l) <20

Strontium (mg/l) <10

Sulfate (mg/l) 400 to 1,000

Total Dissolved Solids (mg/l) 500 to 5,000
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-51

4.0 Air Pollution Issues

The control of VOCs is important for the discharge of water to surface water or groundwater. 

The suggested treatment is air stripping. However, air stripping will require an air permit for this 

discharge. At the Westwater, Utah facility, we have found that capturing these VOCs for energy 

reuse is a cost-effective way of handling this material and results in the facility’s being exempt 

from air permitting, except for the notification process.

5.0 Control of the Brine Stream

The control of the brine stream is currently the most challenging aspect in the overall reuse of 

produced water. The brine stream can have a TDS that ranges from 50,000 to 300,000 mg/l. 

This type of water can be reinjected into a Class II injection well. However, it appears that there 

can be other uses of this water if the scale-formation chemistry has been removed from the water 

stream, such as utilizing the brine as a makeup water for 10-pound brine used in the drilling 

process and the manufacturing of chemistry (hydrochloric acid or bleach solution and sodium 

hydroxide) in the chlor-alkali process. This area requires additional research, but would allow for 

a waste stream to become a usable by-product.

6.0 Potential for Harvesting of Elements from Water

We have also found potential for harvesting metals from this water. For example, in the CBM 

waters of southern Wyoming, the produced water contains a significant concentration of lithium. 

This lithium can be precipitated and captured for sale as a by-product. Additional research needs 

to be done to determine viability, but based on preliminary calculations, lithium recovery could 

be significant.

Lessons Learned from the Treatment of Produced Water and Hydraulic Flowback Water

The lessons learned from the treatment of produced water and hydraulic flowback water are as 

follows:

1. Economics is the primary driver for any type of reuse or recycling effort. If the energy 

company cannot process this water at a cost less expensive than the current disposal 

method, the likelihood of success is small. Therefore, it is important to take into account 

all of the costs, such as trucking, impact to the environment, water sourcing, etc. If these 

items are taken into account, the likelihood of reuse and recycling increases dramatically.

2. Organic removal, including microorganisms, is very important to the overall process. If 

membrane filtration is required, then the removal of heavy organics is necessary as well. 

We have found WSF is critical to this type of treatment process.

3. Organic removal of benzene will be required if the water is to be discharged from the 

facility. This will require air stripping and activated carbon.

4. Inorganic removal, for the control of scale formers and SAR, will be required if reused or 

recycled or discharged to the environment. 

5. If these steps are taken in the treatment of produced water or hydraulic fracturing 

flowback water, then reuse or recycling is certainly possible. This will also address the
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-52

primary concerns—water sources, truck traffic, spills, and air pollution—of the industry, 

regulatory agencies, and environmental groups.

Conclusions

Water reuse and recycling will become one of the controlling factors for hydraulic fracturing of 

oil and gas wells in the United States. It will be crucial for the energy industry to develop the 

criteria for water recycling and reuse and to develop the treatment technologies and testing 

techniques to implement these recycling and reuse projects.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-53

Attachment A. Typical Solution Used in Hydraulic Fracturing
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-54

Attachment B. PTAC Water Decision Tree 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-55

Notes

Matthew E. Mantell, “Produced Water Reuse and Recycling Challenges and Opportunities 

Across Major Shale Plays,” Chesapeake Energy Corporation, March 29, 2011.

“Water Sources and Demand for the Hydraulic Fracturing of Oil and Gas Wells in Colorado 

from 2010 to 2015,” Colorado Division of Water Resources, Colorado Water 

Conservation Board, and the Colorado Oil and Gas Conservation Commission, 2011.

“Sustainable Insight—Water Scarcity: A Dive into Global Reporting Trends”, KPMG, October 

2012.

“Challenges in Reusing Produced Water,” SPE White Paper, 2012.

David R. Stewart, “Analytical Testing for Hydraulic Fracturing Fluids—Water Recovery and 

Reuse,” EPA Workshop for Analytical Chemistry, February 2013.

“Modern Gas Shale Development in the United States: A Primer,” DOE, GWPC, 2009.

Heather Cooley and Kristina Donnelly, “Hydraulic Fracturing and Water Resources: Separating 

the Frack from Fiction,” Pacific Institute, June 2012.

PTAC Water Decision Tree, http://www.capp.ca/getdoc.aspx?DocId=222997&DT=NTV.

US EPA, “Technical Support Document for the 2010 Effluent Guidelines Program Plan,” EPA 

820-R-10-021, October 2011.

Severn Trent Services, http://www.environmental-expert.com/downloads/ion-exchange-systemhiggin-s-loop-brochure-247335.

 

5

“Water Sources and Demand for the Hydraulic Fracturing of Oil and Gas Wells in Colorado from 2010 to 2015,” 

Colorado Division of Water Resources, Colorado Water Conservation Board, and the Colorado Oil and Gas 

Conservation Commission, 2011.

6

“Sustainable Insight—Water Scarcity: A Dive into Global Reporting Trends”, KPMG, October 2012.

7

“Challenges in Reusing Produced Water,” SPE White Paper, 2012.

8 David R. Stewart, “Analytical Testing for Hydraulic Fracturing Fluids—Water Recovery and Reuse,” EPA 

Workshop for Analytical Chemistry, February 2013.

9

“Modern Gas Shale Development in the United States: A Primer,” DOE, GWPC, 2009.

10 Heather Cooley and Kristina Donnelly, “Hydraulic Fracturing and Water Resources: Separating the Frack from 

Fiction,” Pacific Institute, June 2012.

11 PTAC Water Decision Tree, http://www.capp.ca/getdoc.aspx?DocId=222997&DT=NTV.

12 US EPA, “Technical Support Document for the 2010 Effluent Guidelines Program Plan,” EPA 820-R-10-021, 

October 2011.

13 Severn Trent Services, http://www.environmental-expert.com/downloads/ion-exchange-system-higgin-s-loopbrochure-247335.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-56

Marcellus Wastewater Treatment: Case Study

Daniel Ertel, Kent McManus and Jerel Bogdan

Eureka Resources, LLC

The statements made during the workshop do not represent the views or opinions of EPA.

The claims made by participants have not been verified or endorsed by EPA.

Introduction

Natural gas represents an important energy source for the United States (US). According to the 

US Department of Energy’s (DOE’s) Energy Information Administration (EIA), over 20% of the 

country’s energy needs are provided by natural gas. Thanks to the development of new 

nonconventional technology, the development of huge pools of oil and gas reserves, once 

thought to be too deep and held too tightly in shale rock formations, is now happening at a 

feverish pace in several areas of the US and the world. One of the most prominent of these 

“basins” in the US is the Marcellus Shale Basin – underlying large swaths of New York, 

Pennsylvania, Ohio, West Virginia, and Maryland. In the highly competitive US shale gas 

market, it is important for oil and gas (O&G) exploration and production (E&P) companies to 

find efficient solutions to one of the high-cost aspects of production; treatment of development 

and produced waters. Due to scarcity of water resources as well as regulatory constraints and 

expensive treatment technologies, E&P companies must develop and implement innovative 

methods for re-use and adopt more localized and centralized water management systems. E&P 

companies in various shale plays across the US are now consistently seeking out new methods to

transport, dispose, and reuse development and produced water to maximize the profitability of 

shale gas production and remain competitive in a fast-growing market.

This paper covers the following topics with a focus on the Marcellus Shale Gas play in 

Pennsylvania:

History of Eureka

Future Plans

Reuse Strategy

Process Description

Co-Product Reuse Studies

Conclusions/Takeaways

History of Eureka

Eureka Resources, LLC (Eureka) currently provides centralized treatment, recycling and/or 

disposal of flowback/produced waters (wastewaters), as well as waste drilling fluids generated as 

a result of nonconventional natural gas exploration and development activities in the Marcellus 

play. Eureka placed its first centralized pretreatment facility in operation in November 2008 in 

Williamsport, PA with a capacity of approximately 4,800 barrels per day (bpd) or 200,000 

gallons per day (gpd). The facility was originally permitted by the PADEP Bureau of Waste 

Management under WMGR119. In 2010, Eureka opened an expanded centralized treatment 

facility which is currently capable of treating/recycling up to 10,000 bpd (420,000 gallons) of 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-57

flowback/produced wastewater daily. The facility permit was converted to a WMGR123 permit 

at this same time, as authorized by the PADEP Bureau of Waste Management. 

Eureka has the most comprehensive centralized wastewater treatment capabilities in the 

Marcellus play. Eureka’s customers currently have the choice of requesting various levels of 

treatment with the goal of maximizing recycle of:

Pretreated Water - water treated to reduce the suspended solids and heavy metals 

content and readily-settleable dissolved constituents. 

Distilled Water – water treated to remove more soluble dissolved solids,

Concentrated Brine – water very high in TDS which can be reused as a drilling 

fluid additive.

Figure 1. Eureka Oil and Gas Wastewater Facility
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-58

Future Plans

Eureka is in the process of planning, permitting, designing, and constructing facilities to provide 

the following additional wastewater treatment/disposal services in support of nonconventional 

E&P activities below and on Figure 2:

Concentrated Brine Management Options:

o Further centralized treatment using mechanical vapor recompression (MVR) 

crystallizers, with beneficial reuse of a dewatered sodium chloride, calcium 

chloride and other purge stream byproducts

o Deep well injection in Ohio and/or West Virginia

Tertiary treatment of distilled water using membrane biological reactors (MBR) 

followed by reverse osmosis (RO) to generate dewasted water for unrestricted reuse 

[Patent Pending].

Establishment of three more centralized treatment facilities in Pennsylvania, as well 

as possible additional centralized treatment facilities in Ohio and West Virginia.

Dedicated producer centralized or satellite treatment and/or storage facilities.

Figure 2. Eureka’s Expansion Plan
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-59

Reuse Strategy

Eureka’s long-term business strategy focuses on providing a centralized treatment facility for 

development and produced wastewaters that allows maximum flexibility for applying the level of 

treatment necessary to promote reuse of the treated water (see Figure 3). Using this approach, 

Eureka is able to provide the following for potential reuse by E&P companies:

Pretreated Water

Distilled Water

Dewasted Water ( meeting WMGR123 declassification effluent standards)

Concentrated Brine Purge

Dry Salt – Sodium Chloride (NACl) (< 3% moisture)

Calcium Chloride (CaCl2) Brine or Dry Prills

All of the Eureka facilities are permitted such that we can install all or some subset of our 

anticipated unit processes. Our existing Williamsport Facility has oil recovery, pretreatment and 

mechanical vapor recompression distillers (See Figure 4). Eureka’s Standing Stone facility 

(currently under construction) will have pretreatment and first phase (generating commercial 

grade sodium chloride) crystallization in 2013 and is expected to have second phase (generating 

commercial grade calcium chloride brine) crystallization and membrane biological 

reactor/reverse osmosis treatment capability in 2014 (See Figures 5 and 6). Descriptions of the 

unit processes employed by Eureka are summarized below:

Figure 3. Eureka’s Business Plan
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-60

PROCESS DESCRIPTION

Pretreatment:

- Receiving Water

Tanks– Before any 

received water is 

unloaded into the 

partially below grade 

concrete receiving 

water storage tanks, it is 

first evaluated by one 

of the Eureka operators. 

The water is tested for 

total dissolved solids 

(TDS), barium, 

settleable solids, and 

also visually inspected 

for oil. If it passes the 

visual inspection, the truck is unloaded into one of the three concrete receiving water 

storage tanks at the direction of the plant operator.

- Primary Settling Clarifiers/Oil Skimmers – Situated above the concrete receiving 

water storage tanks are three steel clarifiers which are used to collect and remove any 

rapidly settling solids and trap oil. Prior to pumping water into these tanks, the large 

mixers in the concrete receiving water tanks are turned on to fluidize the contents. The 

slurry is then pumped into one of the overhead clarifiers. The heavy solids settle in these 

clarifiers, and the liquid 

overflows a weir and 

pours into a partially 

below grade concrete raw 

water transfer tank by 

gravity. The pump in the 

raw water transfer tank is 

used to transfer the water 

into one of the indoor 

storage tanks. The 

overflow weirs on the 

primary clarifiers are 

setup such that any free 

oil in the clarifier is 

collected at the surface of 

the tank by skimmers and 

stored in portable totes, 

and thus prevented from 

entering downstream 

treatment processes.

Figure 5. Planned Standing Stone Unit Processes

Figure 4. Eureka Existing Williamsport Unit Processes
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-61

- Oil Separation/Recovery Facilities – The oil recovery system consists of a dedicated 

treatment process to treat oil-containing wastewater. A series of aboveground storage 

tanks are used to separate/recover waste oil material that is incorporated into certain types 

of incoming oil and gas 

wastewater received at the 

plant. Incoming oil and 

gas wastewater known to 

contain oil material is not 

discharged to the concrete 

receiving tanks like other 

wastewaters brought to 

the facility. Instead, it is 

directed to one of two 

receiving tanks located in 

the interior space 

immediately adjacent to 

the receiving water tanks. 

As the material in the 

tanks is allowed to 

equilibrate, the oil and water 

components begin to separate. 

Free water is drawn off of the 

bottom of the tanks by pumps and recycled back to the concrete receiving tanks.

The remaining oil/water emulsion is conveyed to a heated tank. Free water forming on 

the bottom of the tank is drawn off by pumps and recycled back to the concrete receiving 

tanks. The remaining oil in the tank is pumped to a recovered oil storage tank. The 

recovered oil is offloaded into tanker trucks and sold. A pre-engineered heater-treater 

system is utilized to provide additional throughput and heat treatment capacity when 

necessary. Oil recovered in the heater-treater is pumped to the recovered oil storage tank, 

and subsequently offloaded into tanker trucks and sold. Water from the heater-treater is 

recycled back to the concrete receiving tanks.

- Indoor Raw Water Storage Tanks – Each of the 10 indoor above grade steel raw water 

storage tanks is equipped with a designated fill line from an overhead manifold that 

allows operators to select which tank to fill from the pump in the raw water transfer tank. 

When in operation, these tanks can also be isolated from the process along a common 

header that supplies a process feed pump. These two features enable operators to 

selectively fill and draw from a given tank or set of tanks in order to manage variable 

water quality. The process feed pumps deliver water from the specified raw water tank 

into pH adjustment/chemical addition tank No. 1 in either Pretreatment Train A or B, 

where chemical treatment begins.

Over time, some solids settle/accumulate in the raw water storage tanks. There are two 

diaphragm pumps connected to the header at the bottom of the raw water storage tanks 

that can be used to transfer solids from the tanks directly into the sludge holding tanks. 

Figure 6. Future Standing Stone Unit Processes 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-62

This is done periodically in order to prevent the accumulation of unmanageable solids 

levels in the tanks.

There is a third header that can be used to put water into each tank individually from the 

final equalization tank in the process. If there is a process upset, this allows operators to 

recycle water from the end of the process back to the raw water tanks in order to manage 

out of spec water.

Chemical Precipitation:

- pH Adjustment/Chemical Addition Tanks – Prior to the secondary clarifiers, there are 

three pH adjustment/chemical addition tanks. Acid (hydrochloric) or alkali (caustic soda) 

can be added to each of these tanks in order to lower or raise the pH when necessary to 

achieve proper metals removals/settling. The second pH adjustment/chemical addition 

tank is used for pH polishing only. In the third pH adjustment/chemical addition tank, a 

coagulant can be added in order to aid in the removal of suspended particles.

- Secondary Clarifiers – Following pH adjustment and chemical addition, the process 

water flows into a clarifier. The settleable particles fall to the bottom of the clarifier 

before being pumped into sludge holding tanks. The resultant clarified pretreated water 

rises to the top of the clarifier from which it flows directly to a final equalization tank.

- Pretreated water is conveyed to Final EQ/Pretreated Water Transfer Tanks. The EQ tank 

serves as a wastewater transfer tank, where pretreated effluent is pumped to pretreated 

water holding tanks. 

Sludge Dewatering:

- Sludge Holding Tanks – The solids from the bottom of the clarifier drains into a sump 

and are then pumped into sludge thickening tanks. The clear water that rises to the top of 

the thickening tanks is decanted by gravity back to one of the pH tanks.

- Sludge Dewatering – Thickened sludge is dewatered using either a plate-and-frame filter 

press, a rotary press or a centrifuge. The dewatered sludge cake is stored in sludge roll-off 

containers, which are hauled away for disposal when filled. The filtrate from the 

dewatering system is recycled back to one of the pH adjustment processes.

Secondary Treatment - Distillation:

- Pretreated Water Holding Tanks – Above grade steel pretreated water storage tanks 

are equipped with a designated fill line from an overhead manifold that allows operators 

to select which tank to fill from the pump at the pretreated EQ tank. Process feed pumps 

deliver water from the pretreated water tanks to NOMAD units. Eureka designs each 

facility with the option to use the process feed pumps to pump the pretreated effluent to 

tanker trucks to allow for reuse of pretreated effluent (i.e., physical-chemical treatment 

only without additional treatment through the NOMAD mechanical vapor recompression 

units) by gas drillers and producers for the extraction of natural gas from various shale 

gas drilling operations. Over time, some solids settle/accumulate in the pretreated water 

storage tanks. Two diaphragm pumps connected to a header at the bottom of the 

pretreatment tanks are used to transfer solids from the tanks directly into the existing 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-63

sludge holding tanks, as necessary.

- NOMAD Units – If distillation treatment is needed, pretreated water is pumped from the 

Pretreatment Tanks into the NOMAD units. The feed water passes through the Feed 

Filter where any residual solids are removed. The feed water flow is then split into two 

streams and directed to the Feed/Distillate Preheat Exchanger and Feed/Concentrate 

Preheat Exchanger with the Feed Control Valves. The feed water heats up to near boiling 

as it recovers sensible heat from the hot distilled water and hot concentrate leaving the 

NOMAD. After the Preheat Exchangers, the two feed water streams combine to a single 

stream and the feed water enters the De-Aerator where non-condensable gases are 

stripped from the feed water and vented to atmosphere.

The feed water drops to the bottom of the De-Aerator column where it combines with a 

large volume of hot re-circulating concentrate. The feed water blends with the recirculating concentrate and then pulled out of the Separator Vessel through a nozzle 

beneath the De-Aerator by Recirculation Pumps. The hot re-circulating concentrate is 

driven from the Recirculation Pumps up through the Evaporator Exchanger where 

approximately 5% of the liquid is vaporized into steam on the outside of the exchanger 

cassettes. The mixture of steam and hot concentrate exits the top of the Evaporator 

Exchanger and flows into the Separator Vessel through the inlet nozzle. Inside the 

Separator Vessel, the hot concentrate separates from the steam by gravity. A vane pack 

type mist eliminator inside the vessel removes small particles of liquid from the steam. 

The steam is drawn from the Separator Vessel through the steam discharge nozzle by the 

Compressor. The Compressor boosts the pressure and temperature of the steam by 

approximately 6 to 8 psi and 18 to 23 F. The hot, high-pressure steam is driven from the 

discharge of the compressor to the Evaporator Exchanger. The steam enters the 

Evaporator Exchanger through the top. As the steam moves down through the inside of 

the exchanger cassettes it condenses into distilled water. The latent heat energy given up 

by this compressed steam as it condenses transfers to the circulating brine vaporizing an 

equivalent amount of brine. The amount of energy required to vaporize the brine are 

equal to the energy needed to compress the steam. 

The hot distilled water is collected in the Distillate Receiver. The discharge pressure of 

the Compressor and steam is determined by the temperature approach required to 

maintain boiling in the exchanger. Operating pressure in the Separator Vessel is 

maintained by regulating the excess steam from the distillate receiver to hold separator 

pressure between 0.75 and 1.5 psi.

- Concentrated Brine Holding Tanks - To maintain a constant specific gravity of recirculating concentrate, a concentrate (or blow down) stream is drawn from the Separator 

Vessel with the Concentrate Pump. The hot concentrate flows to the Feed/Concentrate 

Preheat exchanger, where the concentrate cools down, passing its sensible heat to the 

incoming feed. The cool concentrated brine then flows out of the NOMAD and is 

pumped to concentrated brine holding tanks.

- Pretreated Effluent/Distillate Storage Tanks – The water stored in the distillate tanks 

is either trucked offsite by licensed/permitted haulers for beneficial reuse by gas well 

developers or, if reuse is not an option or under emergency conditions or during periods 

of low demand for treated effluent for reuse, discharged via indirect discharge permit.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-64

Secondary Treatment - Crystallization 

- Crystallizer Unit - The crystallizer unit is used to further process/dewater the brine 

concentrate currently produced by the NOMAD vapor compression distillation units or to 

process pretreated, high TDS wastewater. Brine stored in the concentrated brine holding 

tanks will be pumped to the crystallizer unit for treatment. The crystallizer is operated 

much the same way the distiller is operated using mechanical recompression technology. 

The crystallized salt material and possibly calcium chloride brine produced by the 

crystallization processes will be recovered and packaged for beneficial reuse or hauled to 

a landfill for disposal.

Tertiary Treatment:

− Membrane Biological Reactor (MBR)/Reverse Osmosis (RO) treatment [Patent 

Pending] – The MBR/RO system will allow Eureka to further treat the distilled water 

produced by distillers or crystallizers using biological treatment processes similar to those 

that are typically used at most municipal wastewater treatment plants (See Figure 7). 

Following treatment via these processes, the treated water will meet the declassification 

(dewasting) treatment standards set forth in Appendix A of the revised WMGR123 

regulation recently issued by the PADEP (i.e., it will no longer be regarded as a residual 

waste). In Pennsylvania, this will allow for storage of the effluent in an impoundment or 

other facility under the control of an oil and gas producer prior to reuse as hydraulic 

fracturing water, without required compliance with storage and transportation requirements 

in 25 PA Code Chapter 299. The distilled, dewasted effluent will either be immediately 

trucked offsite by 

licensed/permitted haulers 

for unrestricted beneficial 

reuse by gas well 

developers, or temporarily 

stored onsite to be hauled 

offsite for unrestricted 

beneficial reuse at a later 

date, or discharged directly 

to surface water via a 

direct discharge permit.

Membrane Biological 

Reactor (MBR) - The 

MBR system is 

designed to provide 

biological removal of 

chemical oxygen 

demand (COD) and 

ammonia in the 

distilled water feed. The MBR system consists of feed pumps, a mixed anoxic tank, 

two aeration tanks, the membrane separation system, sludge recycle pumps, an 

automatic sludge wasting system, and final effluent pumps. 

Reverse Osmosis (RO) - The RO system is used as a polishing step downstream of the 

MBR system to remove residual nitrate and sodium that may be in the MBR effluent. 

Figure 7. MBR/RO Implementation Status Summary
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-65

In the RO process, water under pressure will be forced across a membrane element, 

with a portion of the feed permeating (by diffusion) the membrane (“permeate”), and 

the balance of the feed water sweeping along the membrane surface and exiting without 

passing through the membrane (“reject”). During the diffusion process, the membrane 

will freely pass the water molecules but will reject most of the dissolved salts and metal 

ions, the small particles as well as organic compounds and some bacteria. The reverse 

osmosis process will typically convert, or “recover”, a certain percentage, 

approximately 80%, of the initial incoming feed water into “RO permeate”. The 

remaining by-product, or the “RO concentrate”, will contain/concentrate the salts 

rejected by the membrane.

The main single-pass RO system components include a pre-RO membrane cartridge 

skid (with one stainless steel membrane housing), a RO membrane cartridge skid (with 

six FRP membrane housings), one RO feed pump, permeate and reject storage tanks, 

chemical injection systems (for anti-scalant, acid, and sodium bisulfite feed), and a 

clean-in-place system, which will use an FRP tank and a centrifugal pump to circulate 

any one of a number of cleaning solutions used to remove either biological and/or salt 

scaling from the RO membranes.

CO-PRODUCT REUSE STUDIES

Eureka has initiated a co-product determination study designed in accordance with 25 PA Code 

Parts 287.1 and 287.8 (See Figure 8). The study which focuses on beneficial reuse of commercial 

grade dry sodium chloride and liquid calcium chloride is underway and is expected to be 

completed in early 2014.

CONCLUSIONS/TAKEAWAYS

Actual experience treating development and produced wastewaters generated in Pennsylvania as 

a result of the Marcellus Shale Gas play has indicated the following:

Figure 8. Co-Product Reuse Study Status
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

A-66

Eureka’s business plan focuses on locating centralized treatment facilities (employing 

technologies that maximize potential for recycle and beneficial reuse) in close 

proximity to major fairways of development activities to minimize logistics and 

associated costs.

Eureka has over four years of successful experience treating complex unconventional 

Marcellus play flowback and produced waters generated in Pennsylvania, by 

providing the following to their customers:

 Wide range of treatment levels available; allows for flexible wastewater 

treatment strategy.

 Focus on selecting the level of treatment to optimize reuse options and 

reducing impact on hydrologic cycle. 

 Forward-thinking strategic position to stay at forefront of emerging regulatory 

requirements; close dialogue with state regulators regarding the development 

of regulations and standards.

REFERENCES

General Permit WMGR123, Pennsylvania Department of Environmental Protection, March 24, 

2012.

“Permitting Strategy for High Total Dissolved Solids (TDS) Wastewater Discharges”, 

Pennsylvania Department of Environmental Protection.

“Modern Shale Gas Development in the United States: A Primer”, U.S. Department of Energy, 

April 2009.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-1

Appendix B.

Extended Abstracts from Session 2:

Current and Future Trends in Hydraulic Fracturing Wastewater 

Management
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-2

Successful Oilfield Water Management: Five Unique Case Studies

Brent Halldorson

Fountain Quail Water Management

The statements made during the workshop do not represent the views or opinions of EPA.

The claims made by participants have not been verified or endorsed by EPA.

Summary

Oilfield water management includes sourcing fresh water, recycling, disposal, water 

impoundment, conveyance (trucking or pipeline) while also taking into consideration 

environmental, public and regulatory issues. There are also potential reservoir and production 

impacts resulting from fracturing shale formations with different water compositions. Every 

shale play has unique water management issues.

Recycling wastewater associated with shale gas development is challenging due to the varying 

composition of the wastewater. The traditional solution has been to dispose of the wastewater via 

injection wells. While forming part of the solution, disposal alone is not sustainable and 

recycling is required to allow the industry to grow. Fountain Quail pioneered commercial oilfield 

water recycling in the Barnett (TX) and has since expanded into the Marcellus (PA) and Eagle 

Ford (TX). Results and challenges associated with recycling water from various shale plays will 

be discussed.

The ultimate water management plan for shale gas development will include variations of (1) onsite water re-use including TSS removal to allow re-fracturing of wells using saltwater; (2) 

desalination of brine using NOMAD or similar technology; and (3) disposal or beneficial re-use 

of residual wastes such as concentrated brine or salt. Success will require participation and 

cooperation between industry and regulators, a range of technology solutions and common sense.

Introduction 

Fountain Quail Water Management (“FQWM”) pioneered shale water recycling in the Barnett 

Shale and has worked continuously in this field to date. Additional experience has been gained 

through operations in the Marcellus (PA), Eagle Ford (TX) and Permian Basin (TX). Throughout 

this 10 year period water recycling has grown from an emerging new industry into a recognized 

component of developing unconventional oil and gas plays. Recycling has gone from a pilot 

project to an ever-more integral part of oilfield operations.

In this paper FQWM experience will be summarized and five very different case studies will be 

reviewed. For the sake of simplicity “unconventional oil and gas” development will simply be 

referred to as “shale” development, even though this is not strictly accurate. When “shale” is 

referred to in this paper it refers to any unconventional oil and/or gas play where large volume 

hydraulic fracturing is being utilized, regardless of whether it is a true shale or other formation 

(limestone, conglomerate, etc.) being developed.

Water Management – A Complicated Issue?

Water management can prove challenging in shale plays due to the variable nature of the water 

and the dynamic nature of shale development.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-3

In early stage shale plays the drilling program is often chaotic as production companies are 

forced to “drill-to-hold” acreage in order to meet lease commitments. Water management is very 

difficult when there is no structured completion program. Once out of the early “drill-to-hold” 

pattern producers settle into a more structured development program and water management 

becomes easier.

There are five main areas that dominate water management. These are far from allencompassing, however they give the reader an idea of the “big picture” forces at work when 

considering water management in particular shales.

1. Disposal. What is the availability and cost of disposal in the region (typically saltwater 

disposal wells hereafter referred to as “SWD”s)? Is there a possibility of induced 

seismicity due to the depth and formation used for saltwater disposal?

2. Freshwater. What is the availability and cost of freshwater? Often there are competing 

needs from other industries (agriculture) or municipalities.

3. Regulatory and Community. Shale development is occurring in areas that are unfamiliar 

with oil and gas development (PA, OH and possibly NY). Media and public opinion have

often impacted development in these areas, despite gross misinformation and fearmongering. This is a very real issue that needs to be dealt with and it impacts how water 

is managed in these regions.

4. Recycling and Re-Use. Due to the varying subsurface geology, the composition of 

flowback and produced water is radically different from shale to shale. Certain plays 

exhibit very high TDS wastewater (Marcellus, Bakken) and others have relatively low 

TDS wastewater (Fayetteville). The different levels of TDS, hardness and other factors 

impact the relative cost and efficiency of different types of treatment.

5. Transport. This is a simple but often overlooked component of water management.

Trucking is much more expensive than pipelines (on a per-bbl basis) for handling water.

The local terrain and weather have a large impact on the transportation and storage 

options open to producers in that region.

The above factors have different impacts depending on the shale. To demonstrate, 

The Marcellus Shale (PA) has 

very limited disposal, however 

it has abundant freshwater. In 

this shale the predominant 

water management strategy 

generally involves re-using 

saltwater in new hydraulic 

fracturing stimulations in order 

to avoid costly disposal. This 

Figure 1 – Dominant Water Issues

Figure 1. Dominant Water Issues
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-4

works well for early stage development where water is always in deficit (the volume to 

be disposed of can go into a new hydraulic fracturing stimulation), however as more and 

more wells are drilled the volume of produced water (“PW”) will eventually become a 

very real issue due to the limited disposal availability in this region.

The Barnett Shale in north Texas is the polar opposite of the Marcellus. The Barnett has 

abundant low cost disposal due to the Ellenburger formation (immediately below the 

Barnett Shale). The Barnett often struggles with freshwater availability, especially during 

times of prolonged drought as are inevitable in the region.

Coupled with the big picture water issues are the multitude of other water related issues. Certain 

producers may opt for the lowest cost and simply re-use flowback and produced water with 

minimal, if any, treatment. Experience has shown that re-using water with no treatment will 

negatively impact the decline curve of the well due to downhole scale deposition and/or plugging 

of the formation. The question becomes whether the impact on the well decline curve justifies 

water treatment or not. This is a question being addressed by the individual producers and is not 

a topic for this paper.

Other issues include permits for storage and withdrawal of water, NORM management, liability 

for potential saltwater leaks or spills, road damage from trucking water, pit closure costs, odor 

issues, downhole scaling, microbial control, etc. Many more could be listed.

These questions and many more can lead to paralysis and producers become bogged down in 

evaluating the details. It sometimes feels like an “endless DO Loop” with no resolution. Another 

complicating factor is water treatment companies that bombard the energy producers with 

ridiculous unscientific claims, often that make no sense at all or involve “black boxes”.

The point of this paper is to try to simplify these issues and chart a logical water management 

path.

The Big Question: Saltwater or Freshwater?

The fundamental question in shale water management is whether the producer wants to deal with 

(1) saltwater, or (2) freshwater. Once this question is addressed the decisions going forward 

become much easier to deal with. Case studies involving both saltwater and freshwater will be 

discussed later in the paper.

(1) Saltwater.

On the surface, the re-use of saltwater is a 

much lower cost alternative if it is 

practical. FQWM offers basic TSS removal 

utilizing its ROVER clarification system 

for the range of $1/bbl of water treated.

Other service providers offer technology 

such as electrocoagulation, dissolved air flotation (DAF) or filtration to meet customer needs for 

Figure 2. The Big Question: Saltwater or Freshwater?
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-5

saltwater re-use. These are generally high capacity, low cost systems that give back a certain 

quality of saltwater. FQWM prefers the ROVER as it can easily adapt to varying water 

composition and also can provide targeted treatment objectives (i.e.: it can selectively precipitate 

certain species the producer wants to eliminate). Saltwater can be re-used regardless of the TDS 

of the feed – the goal is generally to remove TSS and polymers so that the clean brine can be 

blended with make-up water for new fracture stimulations.

While the treatment options for saltwater are varied and generally low cost, the storage and 

handling of large volumes of saltwater can become very challenging. For example, in Texas the 

producer is required to have an H-11 approved pit to store large volumes of saltwater. The 

permitting and construction of such pits becomes significant for large volume fracs. Case studies 

‘C’ and ‘D below show examples of saltwater re-use scenarios.

(2) Freshwater.

There are very limited technology options for converting shale wastewater into freshwater for reuse. It is often deemed to be impractical and many customers feel it is too costly to consider as 

an option.

The two established technologies for TDS removal include (1) membrane based systems, and (2) 

thermal based systems. Membrane systems have generally struggled to prove effective in oilfield 

wastewater due to poor recovery coupled with susceptibility to membrane damage from 

organics. New developments such as Forward Osmosis (“FO”) show promise for addressing 

some of these issues. The traditional alternative to membranes is thermal distillation, which has 

often been misrepresented as being too costly.

As an example, FQWM offers its patented NOMAD treatment, which is a compact and efficient 

thermal evaporator, for a cost range of $3-$4/bbl (including power, labor, chemical and 

equipment). This is 3-4X the cost of ROVER treatment, however it returns freshwater to the 

customer for re-use rather than saltwater. Despite the higher treatment cost, the customer has (1) 

a predictable hydraulic fracturing water composition (freshwater), and (2) much less headache 

with water storage and transportation. Examples of areas where freshwater makes sense are 

shown below in case studies ‘A’, ‘B’ and ‘E’. 

A by-product of NOMAD treatment is clean, heavy brine (the leftover solution after maximum 

water recovery has been achieved). This “concentrate” often has value to producers that need 

10# brine for drilling and completions. In areas where re-using this heavy brine stream is 

advantageous it makes the freshwater scenario more cost effective. Once the decision as to 

saltwater or freshwater re-use has been made, the remaining decisions on how to implement a 

water management strategy become easier.

Charting a Logical Path Towards a Water Management Strategy

On either path, freshwater or saltwater, simple and achievable goals must be set. It may be 

desirable to start with very basic goals and expand them over time depending on the level of 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-6

success achieved. This should not be considered as “pilot” or “demonstration” treatment, but 

rather a phased in level of treatment starting with the very simple.

Regardless of the plan, both the producers and the treatment provider need to be adaptable and 

flexible. Solutions need to be capable of scaling up in size as the need increases.

Examples of water management goals include the following:

Reuse as much flowback and PW as possible in new fracs (saltwater example).

Eliminate the need for saltwater pits and allow the use of aluminum fastlines (freshwater 

example) without concern for environmental liability.

The overriding goals for each case study will be highlighted below.

Beware of Black Boxes

A complicating factor which has delayed the implementation of water recycling has been the 

entry of new technology solutions which are not based on real science. Often these gadgets make 

promises which cannot be delivered on or which contravene the laws of thermodynamics. For 

example, there are several companies today promoting that their solution is chemical free, uses 

no energy (some create energy!) and have no waste byproduct. In essence they are promoting 

dirty water in and clean water out without having any science behind it. Unfortunately many 

producers have tried these systems and it has left a bad taste for water recyclers in general. The 

old axiom holds true: “if it sounds too good to be true, it probably is.”

Experience trumps wild promises every time. Water recyclers must invest the time and energy in 

learning to treat this highly variable wastewater and customers should stop listening to vendors 

that cannot explain how their systems work.

Some producers are content to run an endless stream of pilot projects. This can gain some insight 

for the producer, however it makes more sense to work with a treatment company that has a real 

product based on real science and together work through the issues. Often the knowledge gained 

through a pilot leaves and has to be re-learned by the next vendor in line.

Case Study A – Freshwater, Devon Barnett Shale

In the early days of the Barnett Shale (north Texas), all the producers were fraccing with 

freshwater and that was the goal for treatment – to get back to freshwater. Fountain Quail was 

fortunate to begin work with Devon Energy in 2004 with the NOMAD evaporator system which 

was developed specifically for shale wastewater. The NOMAD was designed to achieve the 

highest possible recovery of freshwater from shale flowback and PW, while still being easily 

transportable. Devon Energy were pioneers in shale development (formerly Mitchell Energy), 

and their input was valuable in developing the technology.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-7

The objectives for this case study include the following:

(1) Move the recycling to be near the 

drilling activity. This essentially cuts 

the transportation of both the 

saltwater and freshwater by placing 

both in the midst of the current 

drilling activity.

(2) Hydraulic fracturing with freshwater 

alone. This allows for predictable 

hydraulic fracturing chemistry and 

reduced hydraulic fracturing costs 

(using saltwater requires slightly 

more hydraulic fracturing hp and 

additional chemical cost).

(3) Avoids the transport and storage 

issues associated with saltwater. All 

hydraulic fracturing fluid can be stored in freshwater pits (un-lined, non H-11) and can be 

transported via aluminum irrigation pipe.

(4) Water leaks are not a concern and there is no liability from animals drinking the water 

(NOMAD distilled water far exceeds EPA secondary drinking water), water fowl landing 

in the pits or odor issues.

(5) By placing the recycling in the midst of drilling activity, flowback and PW from nearby 

wells can be tied into the mobile recycling center via welded surface poly pipe (rather 

than trucking).

The operation continues today and the nearly 

10 years of experience have been valuable to 

both Devon Energy and FQWM. There have 

been over a dozen different locations 

throughout this time. With low cost disposal 

available in the Barnett Shale, FQWM learned 

to become very efficient so that recycling 

could remain competitive with low cost 

disposal.

In March 2012 the Gas Technology Institute 

(“GTI”) completed a third party evaluation of 

the NOMAD technology at a Devon Barnett 

Facility utilizing a RPSEA grant.[1.] This 

report demonstrates the technical and cost 

effectiveness of the NOMAD treatment system 

on shale wastewater.

Figure 3 – NOMAD Mobile Evaporator

Fountain	Quail	Mobile	 NOMAD	Recycling	Facility.	

3	Hydraulic	Fracture	S mula ons	

using	dis lled	&	fresh	water	

Figure 4 – Devon Recycling Site, Barnett Shale TX 

Figure 3. NOMAD Mobile Evaporator System

Figure 4. Devon Energy Recycling Site, Barnett Shale TX
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-8

Case Study B – Turning PW into Freshwater in West Texas

West Texas contains some of the best oil-producing formations in North America. One of the 

challenges in this area is a lack of available freshwater resources. This client has taken the bold 

approach of using their existing PW as the feedstock for a NOMAD system to create freshwater.

The objectives for this case study include the following:

(1) Reduce and even eliminate the producer’s reliance on groundwater. Use existing PW as 

the source water for development in the region.

(2) Reduce the SWD volume and extend the SWD life. This SWD is owned and operated by 

the producer. By recycling the majority of the PW back into freshwater, the existing 

SWD can now serve for disposal of the NOMAD concentrate alone (clean, nearly 

saturated brine without polymers or TSS).

(3) Utilize a portion of the NOMAD concentrate as 10# brine for drilling and completions in 

the region.

(4) Recover additional oil that is currently going down the SWD well.

(5) Have the ability to recycle high solids flowback from the local area that is currently being 

hauled long distance for disposal.

Disposal of brine and recycling are often viewed as two completely separate options. This case 

study demonstrates that recycling and disposal can be combined to (1) maximize the recovery of 

value-add products such as freshwater, heavy brine and oil, while simultaneously (2) protecting 

and extending the life of the disposal well.

Case Study C – Saltwater Re-Use, Eagle Ford Shale TX

New shale plays initially follow 

chaotic development as producers 

“drill-to-hold” their acreage 

positions. This requires a highly 

flexible and adaptable water 

management strategy. The Eagle 

Ford Shale in south Texas offers an 

example of this type of play.

FQWM developed the ROVER for 

this purpose – to allow customers 

to re-use their brine in a highly 

mobile package at a very low cost.

In its more basic form it is 

removing TSS and polymer using a 

high pH clarification process. This 

is the same pre-treatment that 

FQWM has used ahead of its NOMAD systems for close to a decade. The system has proven 

Flowback 

Produced Water 

Other Treatable Water Streams 

Segregate, skim 

oil, remove

solids, treat water. 

Distilled Water 

(re-use for 

fracs) 

Clean Heavy 

Brine (re-use for 

drilling) 

Solids + any untreatable water 

for disposal.

Maximize Recovery of

Value-Add Products 

Oil ($$$) 

Recycling

Facility 

Optimize & Protect

SWD Capacity 

Figure 5 Recycling “Hub” Combining Disposal and

 Recycling 

Figure 5. Recycling “Hub” Combining Disposal and Recycling
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-9

capable of handling highly variable wastewater influent and delivering consistent, clean brine for 

re-use. Solids are de-watered on the system utilizing a built-in sludge thickener and filter press.

One of the key benefits to a system like this is the flexibility. If the producer wants to remove a 

certain scale forming species, then FQWM can usually precipitate it by varying the chemical 

addition or softening. The cost may go up slightly, however it is still targeting the specific 

treatment needs of the customer at the lowest 

possible cost. In this case study the customer 

wanted to treat flowback and produced water.

The goal was to effectively remove polymer, 

TSS and iron. The ROVER system was 

delivered to site and was completely rigged 

up and operational within 12 hours of arrival.

The system treated all of the flowback and 

PW available. Results from the recycling are 

shown in the figures below.

Figure 6 – ROVER Mobile Clarifier

. '=%#0- 3(<0"> (! '- *1(Y$3%&**&%'"$3(

!

!

! 45674!*, ('&%$)!*, !7&<%$!- +2)!) $>%+; 3 $, '! !

Figure 6. ROVER Mobile Clarifier

Figure 7. Case Study C, ROVER Flowback Results Figure 8. Case Study C, ROVER PW Results
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-10

Case Study D – Saltwater Re-Use, Woodford/Cana OK

This case study shows how inventive producers have become at managing flowback and PW. In 

this case the producer drills all their wells in linear “rows”. As the wells are drilled and 

hydraulically fractured, the flowback is hard-piped along the row back to a tank. This flowback 

is blended with make-up water (fresh) and used to hydraulically fracture the next well (without 

treatment).

The objective of this case study was to evaluate whether or not to remove the TSS and polymer 

from the flowback prior to re-use. After studying the water, it was determined that the water was 

easily treatable with a ROVER mobile clarification system. The turbidity could be dropped from 

600 to 5 NTU. The ROVER treatment could achieve this goal for a budget price of $0.79/bbl.

The customer struggled to quantify whether the removal of the TSS and polymer (and reduced 

scaling index) would have a significant impact on their oil production.

In this case the customer opted to do nothing and continue without treatment. Sometimes this is 

the answer and recyclers need to understand and accept that “no treatment” might be part of a 

successful water management strategy. 

1	 2	 3	 4	 5	

Flow-	 Back	 Make- Up	

ROW 1 

Flowback from Well #1

100% Re-Use for Well #2

1	 2	 3	 4	 5	

ROW 2 

Complete	ROW,	Re-Using	Flowback	 Move Tanks When ROW Complete

Figure 9 – Case Study D, “Row” Development 

1	 2	 3	 4	 5	

ROW 1 

1	 2	 3	 4	 5	

Flow-	 Back	+	

PW	

Make- Up	 ROW 2 

Flowback from Well #1

100% Re-Use for Well #2

PW from ROW 1

Q: Should TSS, Fe & Polymer be removed

prior to re-use?

Figure 9. Case Study D, “Row” Development
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-11

Case Study E – Brackish Water Study, Wise County TX

This case study demonstrates a unique challenge and creative solution. The customer has limited 

freshwater in this Barnett Shale county (Wise county), however they do have “brackish” 

saltwater wells. Despite this, the customer still prefers to hydraulically fracture wells with 

freshwater.

In this case it makes sense to look at membrane technology to desalinate the brackish saltwater 

(consistent composition, no hydrocarbon). FQWM came up with the following “hybrid” solution 

utilizing an RO system to treat the brackish water and also using a NOMAD evaporator to treat 

the RO reject combined with flowback and PW in the region.

The customer continues to study this idea and may set up a small scale system initially. This 

demonstrates how different technologies can be combined to arrive at a solution. Texas has 

ample brackish water and there are many ways that it can be incorporated into a water 

management plan, either by using it directly or treating it to freshwater as demonstrated in this 

case study.

Conclusions

These case studies demonstrate how both freshwater and saltwater re-use can be successfully 

incorporated into an energy producer’s water management strategy. To arrive at a solution the 

customer must be prepared to answer the initial question: freshwater or saltwater? After this it is 

a matter of laying out simple and achievable goals and selecting a treatment partner or 

technology that is based on real science and has actual oilfield experience.

Both the producer and the treatment company must be committed to working jointly through the 

issues as they arise, and success will inevitably follow.

Distilled Water 

RO Permeate

RO Reject

Saltwater Well

RO System 

Flowback & PW

10# Brine

SWD

Bypass (up to 2,000mg/L) 

147gpm 

15gpm 

99gpm 114gpm 

33gpm 

77% RO 

recovery if you

factor in the

bypass.

Figure 10 – Case Study E, Brackish RO + NOMAD

Figure 10. Case Study E, Brackish RO + NOMAD
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-12

Acknowledgments

Devon Energy has been invaluable as a resource and partner for FQWM. Not only has Devon 

helped launch FQWM as a recycling service provider, it has tested dozens of other technologies 

and continues to be an example of pioneering new and better ways of developing oil and gas [2.].

Note: This paper has been re-printed with permission of the AADE.

Copyright 2013, AADE. This paper was initially presented at the 2013 AADE National Technical Conference and Exhibition held at the Cox Convention Center, 

Oklahoma City, OK, February 26-27, 2013. This conference was sponsored by the American Association of Drilling Engineers. The information presented in this 

paper does not reflect any position, claim or endorsement made or implied by the American Association of Drilling Engineers, their officers or members. Questions 

concerning the content of this paper should be directed to the individual(s) listed as author(s) of this work.

Nomenclature

DAF Dissolved Air Flotation.

FQWM Fountain Quail Water Management, LLC.

GTI Gas Technology Institute

NORM Naturally Occurring Radioactive Material.

NTU Nephelometric Turbidity Unit, Turbidity Measurement

RRC Texas Railroad Commission

TSS Total Suspended Solids (stated in mg/L or ppm).

TDS Total Dissolved Solids (stated in mg/L or ppm).

References

1. Hayes, Tom, Ph.D., Severin, Blaine F., Ph.D., PE.: “Evaluation of the Aqua-Pure Mechanical 

Vapor Recompression System in the Treatment of Shale Gas Flowback Water – Report 

#08122-05.11.” RPSEA Contract 08122-05. March 12, 2012.

2. Ewing, Jay R. PE, Werline, Rusty, PE: Devon “Culture of Achievement – Pioneering Water 

Recycling” video regarding water recycling projects, www.dvn.com.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-13

Produced Water Management in the Marcellus

Meagan S. Mauter1,2 and A. Patrick Behrer2

1

Engineering and Public Policy, Chemical Engineering, Carnegie Mellon University

2

John F. Kennedy School of Government, Harvard University

The statements made during the workshop do not represent the views or opinions of EPA.

The claims made by participants have not been verified or endorsed by EPA.

Controversy continues to surround the deployment of horizontal drilling and hydraulic fracturing 

technologies for natural gas extraction from sub-surface shale. Comparative life-cycle 

assessment has demonstrated reduced CO2e/mmBTU emissions from electricity produced from 

shale gas compared to coal, while highly localized impacts of hydraulic fracturing have been 

reported for fresh water aquifers within one mile radius of a wellhead. While global and local 

analyses are important for strategic management and regulation of shale gas resources, regional 

level impacts and benefits often drive state-level policy in resource extraction. Quantifying these 

regional impacts by summing over a set of regional wells also helps to define variance in single 

well impacts, which can hinge both on exogenous variables as well as on the management 

decisions, experience, risk aversion, and commitment of the operators. Determining the origins 

and magnitude of this variability is valuable to operators, regulators, land-holders, and 

environmental advocates alike.

We find significant variation in the waste management practices and drilling patterns of 

Marcellus firms. A large portion of this variance is attributed to waste disposal method, 

company experience operating in the Marcellus, and drilling practices suggesting that impact 

minimization is a function of firm-level decision making on a highly localized scale. Among the 

most important strategic interventions is the practice of synchronizing drilling operations in time 

and space, or clustering. Companies that drill their wells in clusters reuse a larger percentage of 

waste and minimize total waste transport.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-14

Mid-Continent Water Management for Stimulation Operations

D. Steven Tipton, P.E.

Newfield Exploration Mid-Continent, Inc.

The statements made during the workshop do not represent the views or opinions of EPA.

The claims made by participants have not been verified or endorsed by EPA.

Introduction: Water, its use and management is critical to the petroleum industry. It is the most 

common and heavily used fluid in the oil and gas business. In every jurisdiction in this country 

its use is regulated in some manner. The regulations and ownership of water is different in each 

area in which the industry works. In many areas of the country the use and handling of water 

have become emotionally charged. For this presentation, I will be concentrating on the water use 

and reclamation for the stimulation of the Granite Wash tight gas reservoirs in the Anadarko 

Basin and the shale oil reservoirs of the Cana Woodford Shale in the Anadarko Basin. Both areas 

have evolved as the drilling activity increased and changed. In each area an infrastructure has 

been created to support Newfield’s completion operations and the need for water. 

Water Management Cycle:

Source: Granite Wash – ground water

Woodford Shale – surface ponds

Cana Woodford – ground water, 

surface ponds, lakes, and streams

Transport: Fresh water is pumped through 

aluminum, poly pipe, PVC pipe, 

lay-flat hose or trucked. Recycled 

water is pumped through poly 

pipe, lay-flat hose or trucked to the 

well site.

Store: Fresh water is stored in ponds or lined pits. 

Recycled water is stored in lined pits or hydraulic fracturing tanks.

Stimulate: Halliburton, Schlumberger, BJ or other companies mix the water with proppant 

and other chemicals and pump it into the well to stimulate the reservoir.

Flowback: Flowback water is separated from any hydrocarbons at the well’s test or 

production facilities. It is then pumped or trucked to a recycle pit or a disposal 

well. 

Recycle Once at the recycle facility the flowback and/or produced water is processed and

or Disposal: cleaned up for reuse. The water that is not reused will be taken to a disposal well.

Figure 1. Water Management Cycle
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-15

NFX Granite Wash Operations: Newfield’s Britt Ranch and Briscoe 

fields were originally drilled for deep Morrow gas during the 1980’s. 

The Morrow is a conventional gas condensate reservoir. The Granite 

Wash is very tight laminated reservoirs in Western Oklahoma and the 

Texas Panhandle. From 2001 until 2008, Newfield drilled over 150 

vertical Granite Wash wells. Beginning in 2008, all of the wells 

Newfield drilled in the Granite Wash have been 

horizontal. Initially, hydraulic fracturing tanks or hydraulic fracturing 

pits were used at each well site for the completion operation. It soon 

became apparent that having central water supply pits was more 

economical. As the amount of water being used increased and the cost of 

potassium chloride went way up, it made economic sense to begin 

recycling flowback water. When Newfield started drilling and 

completing horizontal wells in this area the water usage went from 

approximately 80,000 barrels per completion for vertical wells to over 

250,000 barrels per completion for horizontal wells. 

Although in most areas 10” aluminum irrigation 

pipe is used to transport fresh water, Newfield uses 

its own HDPE (high density polyethylene) to move 

it from the water storage pits to the completions. 

The recycled water is transported through either 8” 

or 12” HDPE pipe. 

Newfield owns 38 miles of 8” poly, 4 miles of 12” and 10 miles of 4” poly to move water from 

pit to pit, from the pits to the wells being stimulated and from the wells back to the recycle pits. 

Generally three or four lines are used to deliver water from the hydraulic fracturing pits to the 

well being completed. Once the completion is finished and the well begins to flow back one poly 

line is left in place to pump the water back to the pit. Newfield also owns 6 water transfer pumps 

to move water from the flow back or production tanks to the recycle pits.

The water being produced into the recycle pits contains approximately the same TDS as the 

water used during the completion operation (15,000 to 20,000 mg/l) and is relatively clean. Any 

solids produced with the water will drop out in the flow back pits. By reusing the water, 

Newfield saves over $30 million per year in reduced water disposal costs, $8 million per year by 

not purchasing potassium chloride and another $1 million a year by not purchasing additional 

fresh water. The hydrocarbons not caught in the production equipment (less than 500 mg/l) are 

skimmed from the pits as is necessary and recycled through our disposal facilities.

Currently, Newfield recycles approximately 80% of the water it uses. The company would 

recycle more however not all of the wells produce back their entire load. In addition, the pits are 

permitted only for fresh or flowback water, so once the entire load is recovered the produced 

water must be trucked or piped to a SWD well. In the Britt Ranch area, the company has seven 

recycle pits with a total capacity of 2.4 million barrels and ten fresh water pits with a total 

Figure 4. Recycle Pump

Figure 2. Map of 

Anadarko Basin

Figure 3. HDPE
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-16

capacity of 1.3 million barrels. In the Briscoe area there are two recycle pits with a total capacity 

of 900,000 barrels. Due to the soil conditions and to protect the environment all of the pits are 

lined with geomembrane liners. 

The Texas Railroad Commission permits each of the recycle pits. The pits are inspected before 

they are used and then drained at least once a year and re-inspected. Some of the pits have been 

in use for more than five years without a leak or failure. 

As stated above, Newfield has a long history of drilling vertical wells in the Granite Wash. Since 

the Granite Wash has multiple pay zones the focus had been on drilling vertical wells and 

completing all of the zones using multiple hydraulic fracturing stages. Using this approach the 

best vertical well in the area had an initial production rate of 9.2 MMCFD and 48 BOPD with 

over a 90% initial decline rate when completing eight of the zones. An average vertical well 

initially produces at a rate of approximately 5 MMCFD with multiple zones completed. After

much work, a horizontal well was drilled and completed in the upper member of the Granite 

Wash during the fall of 2008. That well initially produced at a rate of 25 MMCFD and 1500 

BOPD and produced 2 BCF and 100,000 BO in its first four months. Since that time eleven 

individual zones have been tested in the Granite Wash with horizontal completions. The average 

initial production of 17 MMCFD and had a much lower decline rate than the vertical wells. As 

can be seen with these numbers, horizontal wells have substantially improved both the initial 

productivity and recoverable reserves from the Granite Wash. 

With the horizontal wells has come the demand for much more water. The average vertical well 

was completed using 80,000 to 100,000 barrels of water. The average horizontal well is using 

250,000 barrels of water or 25,000 barrels per hydraulic fracturing stage. Experiments have been 

conducted using different perforating schemes, water volumes (from 5,000 barrels to up to 

55,000 barrels per stage) and pumping rates 

(from 60 to over 100 barrels per minute). Since 

some of the zones are up to 600 feet thick, 

attempts have been made to see if the zones 

could be drilled with just one lateral and get 

sufficient height from the hydraulic fracturing to 

recover the reserves efficiently. Based on the 

hydraulic fracturing mapping, we have not been 

able to achieve the hydraulic fracturing height 

desired. These attempts to intentionally increase 

the hydraulic fracturing height have proven that 

in most cases getting more than 250 feet of 

height growth is very difficult. The probability 

of fracturing into a USDW zone more than 

10,000 feet above the reservoirs being 

stimulated is very implausible.

Due to the large amount of water required to complete some of the wells, the pits have been 

“daisy chained” together using poly pipe so that water can be moved from pit to pit. Using this 

approach two wells were recently completed on the same pad using over 800,000 barrels of 

Figure 5. Britt Ranch Piping Layout for 

800,000 bbl completion of 2 wells
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-17

water with the fracs being pumped at over 100 barrels per minute and water moved up to nine 

miles. The figure to the left depicts the pipe system used to connect the pits to each other and the 

wells being completed.

The approach Newfield has taken in its Granite Wash water management 

is being used as the model for new projects in Western Oklahoma, the 

Eagle Ford in South Texas, the Wasatch in Eastern Utah and the 

Marcellus. Other operators in the area are also copying Newfield’s model.

NFX Woodford Shale Operations: Newfield’s Woodford Shale 

operations are conducted over a 900 square mile area in the Arkoma Basin. 

The Woodford Shale was initially developed with vertical wells with the 

best initial production being 1,600 MCFD and the average well’s initial 

production ranged from 300 to 400 MCFD. Newfield began drilling and completing horizontal 

Woodford wells during the spring of 2005. During the last eight years the lateral lengths 

increased from 2500 feet to over 10,000 feet with corresponding increases in initial production 

rates. The average initial producing rate for Newfield’s Woodford wells is 7.0 MMCFD. At this 

time, operations in this play have been suspended due to low gas prices.

Fracturing volumes on the vertical wells were generally small (less than 10,000 bbl) and could be 

done from hydraulic fracturing tanks or a small fresh water pond. 

To achieve higher producing rates from the Woodford wells, 

much larger fracture stimulations with volumes increasing up to 

300,000 barrels per well were required. Some of Newfield’s four 

well pads have used up 1.2 million barrels of water during the 

completion operations.

As the horizontal play developed Newfield built over 60 fresh 

water ponds to collect run off from rainwater. The ponds ranged 

in size from 50,000 to over 750,000 bbls with a total capacity of 

over 8 million barrels. Fresh water was transferred from the 

pond to the well sites through 10” aluminum irrigation pipe. In 

cases where there was not enough fresh water in one pond they would be connected together 

using irrigation pipe and the water moved from pond to pond. Fresh water has been moved up to 

2.5 miles during the hydraulic fracturing operations. Recycled high chloride water was trucked 

from our Ecosphere water treatment facility to the well site where it was stored in hydraulic 

fracturing tanks. Fresh water was then mixed with the recycled water through the hydraulic 

fracturing blender to make an equivalent of one percent potassium chloride water.

Ecosphere is a company Newfield used to clean its flowback water for use as a potassium 

chloride substitute. The technology provided by Ecosphere Energy Services, LLC, uses ozone to 

oxidize hydrocarbons, residual chemicals and heavy metals in the flowback water. This process 

also kills any bacteria in the water, reduces the surface tension of the water and reduces sulfate 

and carbonate scaling tendencies. Their process also uses hydrodynamic cavitation, electro 

chemistry, acoustic cavitation and various types of filtration. Should it be desired to reduce the 

Figure 6.

Arkoma Basin 

Map

Figure 7. Fresh Water 

Hydraulic fracturing Pond
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-18

salinity the unit is equipped with reverse osmosis units. Newfield saved over $13 million per 

year in reduced chemical usage by using Ecosphere to clean its recycled water. 

Once the completion was finished and the well flowing back, the produced water was trucked to 

a salt water disposal facility. The Ecosphere equipment is located at one of Newfield’s salt water 

disposal wells and uses the water there as its source. The processed water was stored in hydraulic 

fracturing tanks until it is needed. At the time, only six percent of the hydraulic fracturing water 

in Newfield’s Arkoma Basin operation was recycled.

Until Newfield suspended its operations in the Arkoma Basin, 

it was working on locating a place for recycle pits and being 

able to use higher chloride water as a hydraulic fracturing fluid 

so that more water could be recycled.

NFX Cana Woodford Operations: For the last two years 

Newfield has been in the exploration phase of a program in an 

oil rich area covering 10,000 square miles in Central 

Oklahoma. Only fresh water is currently being used for its 

hydraulic fracturing fluids. Newfield has been able to cut its water use by 2/3 by changing from 

slick water hydraulic fracturing’s to cross-linked gel hydraulic fracturing’s. With the drought it is 

quite apparent that another source of water must be found and used. Newfield is working toward 

recycling the hydraulic fracturing water in areas where its infrastructure has grown to a point that 

it makes economic sense. Reuse of the cross linked gel water presents greater challenges than 

reuse of the slick water. Newfield and its vendors are in the process of working out the hydraulic 

fracturing fluid chemistry, water cleanup technology, and getting pits permitted for the use of 

recycled water.

Conclusion: Newfield has recycled over 50 million barrels of water and saved over $200 million 

in completion costs in its Britt Ranch operations. Newfield’s Granite Wash operation is a prime 

example of where recycling hydraulic fracturing water is environmentally responsible and 

economically feasible at the same time. This is a win-win for the landowners, the community, 

and the company. 

Figure 8. Fresh Water 

Hydraulic fracturing Pit
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-19

Utilizing Models Developed for Water Management and Risk during Carbon Storage to 

Improve Water Management during Unconventional Gas Exploration and Production

Enid J “Jeri” Sullivan1and Rajesh Pawar2

1Chemical Diagnostics and Engineering Group, Los Alamos National Laboratory

2Computational Earth Sciences Group, Los Alamos National Laboratory

The statements made during the workshop do not represent the views or opinions of EPA

The claims made by participants have not been verified or endorsed by EPA.

Introduction 

The extraction of produced water during carbon storage is used to control subsurface reservoir 

pressure gradients and the flow of stored CO2 plumes as a risk management strategy. Treatment 

and repurposing of this water creates a useful resource and reduces the volumes that must be 

disposed. Models have been developed to assist decision-making and acceptable risk policy 

making related to water production, treatment, and use during the carbon storage process [1-5]. 

Likewise, similar models are needed to support decision making and management related to 

water extraction and use during unconventional gas exploration and production.

Existing models (e.g., water treatment modules in CO2-PENS) derive their processes and 

substantiating data extensively from produced water databases, brackish and seawater treatment 

processes, enhanced oil recovery data, and other published literature and engineering studies 

related to oil and gas production. Many of the processes, including pretreatment, treatment, 

concentrate disposal, and transport, are applied to water qualities similar to or the same as those 

of oil and gas produced water and/or hydraulic fracturing fluids (collectively referred to here as 

PW). The resulting information informs us about the feasibility of the treatment and management 

systems chosen and the cost versus risk scenarios.

Our current work includes evaluation of transportation and storage costs, improvement and 

expansion of supporting data for cost values and ranges, and additional sensitivity analyses.

Because of the similarities that exist between carbon storage and hydraulic fracturing, including 

large extracted volumes, high salinities, and potential treatment methods, models used for carbon 

storage water extraction processes are anticipated to translate well into process models that can 

assist with volume management, pretreatment and treatment, transport and disposal, and use and 

reuse of water used in hydraulic fracturing and gas recovery. Utilization of existing models from 

carbon storage research will allow fast implementation and evaluation of processes, costs, and 

risks in the rapidly evolving hydraulic fracturing and unconventional energy production industry.

Model types, time scales, and system scales 

Pore-scale chemistry and flow models (e.g. PFLOTRAN) can be used for small-scale phenomena 

on shorter time scales (seconds to years), and can be used to measure mineral-fluid, fluidfracture, and porous-media interactions. Local or site-scale flow and transport models (e.g. 

Modflow) can evaluate local well impacts such as well bore leakage or fracturing return flows 

(days to years). Site- and local-scale system and process models (e.g. CO2-PENS; GTI 

spreadsheet model) can be used to integrate processes such as injection, extraction, treatment, 

and transport (days to years); then can be used to evaluate costs and risk impacts [6, 7]. Field-
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-20

scale (regional) and basin-scale flow and transport models and model platforms (e.g., Modflow, 

PFLOTRAN,mASCEM) are used to model water flow and balances, salt or contaminant 

transport, collective impacts of pore- or local-scale processes, and can be used for short or long 

time frames (days to years). We note the critical importance of real-time and historical field data 

to calibrate and verify models [7]. To date, several site-scale models have been developed, but 

large-scale modeling has not yet been attempted, at least not to the level done for carbon storage 

projects. Cross-scale linkages of models for carbon storage are feasible and are needed for 

hydraulic fracturing systems, for near- and long-term time scales [8].

Needs for models to address:

1. Fresh water (drinking water) management and impacts—predict use, reuse, losses via 

disposal or evaporation, impacts on other energy production (e.g., power plant intakes; 

ecological impacts; agricultural impacts)[9, 10].

2. Salt water management and impacts-use, reuse, spills, disposal to surface bodies, disposal 

to wells (volume and time limitations), outcomes, energy use, and costs of treatment;

transportation, reuse, and disposal; pipeline network expansion; impacts of regulation 

[11-14].

3. Salt and inorganic constituent inventories and management—extraction from shale via 

PW/flowback; treatment; creation of saline concentrate streams and solid salts; disposal 

to wells and formations; impacts to reuse from chemistry changes over multiple cycles [7, 

14].

4. Risk Modeling: similar to that done to evaluate risks for CO2 storage [8]; must be robust, 

up-to date, and flexible. Includes reservoir storage and potential leakage pathways, 

fracture propagation and effects of propagation including seismic and chemical 

interactions in subsurface; impacts on fresh water reservoirs. Also should include the 

effects of increased environmental regulation and linkages with economic analyses and 

the impacts of forecasted climate change [11].

5. Economic and cost analysis: Similar to that done to evaluate CO2 water management 

strategies [3]. Effects of system expansion, environmental regulations, impacts on 

producers and the market, impacts of the market on production, infrastructure costs; 

transportation costs, life-cycle analysis [11]. 

Here we discuss the site-scale water management tool within CO2-PENS, including current uses 

and future utilization for system modeling for hydraulic fracturing processes; We introduce the 

ASCEM model (developed for DOE-EM contaminant and environmental studies), and PFlotran 

(used for ecological and contaminant studies) as possible additional models for large regional 

scale assessments and linking pore- and fracture-scale phenomena to larger-scale models.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-21

Methods

We use a systems approach to evaluate treatment costs that are reasonable for the chemical and 

physical qualities (salinity, temperature, pH and turbidity) of water that could be extracted from 

target geologic carbon storage formations (Figure 1). The temperatures and salinities of water 

extracted during unconventional gas production 

fall within ranges evaluated for carbon storage. 

The system model was developed using the 

GoldSim©platform linked to a Fortran code 

[15]. GoldSim©provides utilities that can be 

used to develop analysis models designed to 

perform multi-realization, probabilistic 

simulations. The model also has various data 

elements to input user-specified parameters 

including stochastic distributions. The 

preliminary model captures all decision points

(Figure 2). 

We evaluated generalized cost scenarios based 

on data found in the literature for brackish (15,000 mg/L TDS) through highly saline (80,000 

mg/L TDS) water qualities, four electricity costs (0.04, 0.07, 0.10, and 0.20 $/kWh), and variable 

temperatures from 15-120 °C (to account for variation from cool stored surface water to 

superheated high-salinity waters). Several methods of treatment, including nanofiltration (NF), 

reverse osmosis (RO) and thermal methods (multistage flash distillation, multiple effect 

distillation, thermal vapor compression [MSF, MED, TVC]) are included in the model [3, 4]

(Figure 2). Recent model additions include organic pretreatment methods (oil/water separation, 

filtration, adsorption, oxidation) and transportation costs (pipelines, trucks). The user can select 

various choices of input volume, temperature, salinity, location, and electricity costs to obtain 

output treatment types and costs, and feasible concentrate disposal methods and costs [3]. 

Results and Discussion

Our data indicate that for waters extracted from carbon storage sites, salinities and temperatures

may often be higher than for municipal seawater and brackish water treatment scenarios (Figs. 1 

and 3). The temperatures and salinities of extracted waters are similar to that of unconventional 

PW. Thus, thermal treatment methods are more 

cost-feasible than membrane methods in many 

cases, although pressure recovery methods for 

RO can mitigate this. Treatment costs including

concentrate disposal fall within a range of

US$0.50 to US$2.50/ton CO2 injected, although

some costs can be much higher (up to 

US$30/ton CO2 under certain concentrate 

disposal cost ranges). These values can be 

converted to m3of water when CO2 density is 

known (Figure 3). A sensitivity analysis 

RO 2-3 

passes

RO 1 

pass

Minimum TDS for 

CO2 Sequestration 

Maximum 

TDS for 

RO, NF

Figure 1. Ranges of temperature and salinity 

for treatment options. 

Figure 2. Primary treatment conditions and 

selection criteria.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-22

showed that temperature is most important in determining costs, followed by selection of 

concentrate disposal method.

The Rock Springs Madison Fm. (Wyoming, Teapot Dome region) was chosen for modeling 

because the formation has a higher salinity range (>45,000 mg/L), thus ruling out RO treatment 

methods in the model. A produced water scenario was evaluated in order to include Class II well 

disposal costs (Figure 4). The model also selects an evaporation pond scenario for disposal; 

limiting factors include a humid climate and the availability of land area for ponds. While some 

high cost ranges are shown (up to $29/ton CO2) most costs fell below $2.50/ton CO2 using a 

$0.10/kWh electric cost input; these can be lowered if thermal energy can be designed to be a 

larger contributor to the energy costs at these sites.

Volumes of extracted water treated after carbon storage are predicted to be very large in some 

cases, ~1 km3over 50 years [16, 17]. The volumes of water extracted are very similar to those 

projected for fracture flowback during gas recovery phases. The large, and temporally variable, 

extracted volumes are projected to impact management and treatment costs considerably. We 

have evaluated volumes up to 10 mgd (37,854 m3) in our current scenarios. Methods for 

handling and storing such large quantities should be included in hydraulic fracturing system 

models to evaluate infrastructure and cost impacts.

While system models are convenient ways to make near-term management decisions, larger 

scale models are needed to look at longer term, multi-dimensional and multiphysics scenarios. 

CO2-PENS provides large scale system transport and pressure/chemistry interactions of gas and 

fluids. ASCEM is a state-of-the-art physics-based approach for predicting contaminant fate and 

transport. It is based on a modular, extensible, and open source design that leverages existing 

0.00

0.50

1.00

1.50

2.00

10000 15000 20000 25000 30000 35000 Cost to treat water ($/m^3 of output treated water)

TDS (ppm)

RO 50% treated RO 90% treated NF 50% treated NF 90% treated

Thermal 50% treated

Thermal 90% treated

Figure 3 (right). Cost to treat in $ per 

m

3

of output treated water with a 

constant injected CO2 density (water 

volume normalized to 37,854 m3or 10 

mgd). Variable TDS (<35,000 mg/L) 

and temperature (15°C to 65°C), 

desired treated water recoveries=50% 

and 90% of feed volume, energy cost 

=$0.10/kWh, MSF thermal rate, no 

pressure recovery, no disposal options 

included, 100 modeled realizations.

Figure 4 (left). Cost to treat in $/ton CO2

injected Formation=Rock Springs 

Weber Fm., variable TDS (15,000-35,000 

mg/L) and temperature (10-117°C), 

energy costs=$0.10/kWh, MSF thermal, 

Pelton pressure recovery included, 500 

realizations. 

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0 5000 10000 15000 20000 25000 30000 35000

TDS (ppm) Cost to treat water ($/ton of injected CO2)

Disp-Class I well

Disp-Class V well

Disp-Evap pond

Disp-ZLD

ElPaso_RO

Al Shoaiba_thermal
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-23

high-performance computing capabilities (many developed through DOE SC-ASCR). It 

currently provides a dynamic and evolving community platform across many DOE sites, for 

testing and integrating the processes behind large-scale contamination problems. The model 

integrates key tools into single framework, including simulation, data management, visualization, 

parameter estimation and uncertainty quantification. PFLOTRAN, a multi-scale chemistry and 

flow model, can be integrated with ASCEM. These models have been used for contaminant 

transport at DOE sites and understanding the evolution of permafrost melting and subsurface 

flow in the Arctic. In combination, the two can be used to promote understanding of the effects 

of unconventional gas extraction methods on basin scale resource use, while incorporating 

climate change, regulation, and economics parameters.

Acknowledgement 

This work was funded in part by the US DOE’s Office of Fossil Energy through the National 

Energy Technology Laboratory’s Carbon Sequestration Program.

References

1. Sullivan, E.J., et al., A system model of methods, processes, and costs for treatment of 

water produced during CO2 sequestration, in 9th Annual Carbon Capture and 

Sequestration Conference2010: Pittsburgh, Pennsylvania.

2. Sullivan, E.J., Chu, S., Stauffer, P. and Pawar, R.J., A CO2-PENS model of methods and 

costs for treatment of water extracted during geologic carbon sequestration, in 

Desalination for the Environment: Clean Water and Energy, M. Balaban, Editor 2012, 

European Desalination Society: Barcelona, Spain.

3. Sullivan, E.J., et al., A method and cost model for treatment of water extracted during 

geologic CO2 storage. International Journal of Greenhouse Gas Control, 2013. 12(0): p. 

372-381.

4. Klapperich, R.J., et al., IEAGHG, "Extraction of Formation Water from CO2 Storage", 

2012, IEAGHG: Cheltenham, GLOS, United Kingdom.

5. Kobos, P. Combining Power Plant Water Needs and Carbon Storage using Saline 

Formation: An Assessment Tool. in Eighth Annual Conference on Carbon Capture and 

Sequestraton-DOE/NETL. 2009. Pittsburgh, Pennsylvania.

6. Sullivan, E.J., Chu, S., Stauffer, P.H., and Pawar, R.J., Development of a system model of 

methods, processes, and costs for treatment of water extracted during carbon 

sequestration, in Energy Resources and Produced Water Conference 2010: University of 

Wyoming, Laramie, Wyoming.

7. Hayes, T., Keynote: DUG East Technical Workshop: Water Management and 

Environmental Procedures, 2011.

8. Middleton, R.S., et al., The cross-scale science of CO2 capture and storage: from pore 

scale to regional scale. Energy & Environmental Science, 2012. 5(6): p. 7328-7345.

9. U.S.EPA, Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water 

Resources: Progress Report, 2012: Washington, D.C. p. 278.

10. U.S.EPA, Plan to Study the Potential Impacts of Hydraulic Fracturing on Drinking 

Water Resources, 2011, Office of Research and Development: Washington, D.C. p. 190.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

B-24

11. Logan, J., et al., Natural Gas and the Transformation of the U.S. Energy Sector: 

Electricity, 2012, The Joint Institute for Strategic Energy Analysis: Golden, CO. p. 255.

12. Rassenfoss, S., From Flowback to Fracturing: Water Recycling Grows in the Marcellus 

Shale, in Journal of Petroleum Technology2011. p. 48-51.

13. IAEA, Desalination Economic Evaluation Program (DEEP), 2011, International Atomic 

Energy Agency.

14. Drewes, J.E., An Integrated Framework for the Treatment and Management of Produced 

Water, 2011, RPSEA: Boulder, Co. p. 65.

15. Goldsim Technology Group, GoldSim Probabilistic Simulation Environment User’s 

Guide, Version 10.5. Volumes 1 and 2., 2010, GoldSim Technology Group LLC: 

Issaquah, Washington.

16. Stauffer, P.H., et al., Greening Coal: Breakthroughs and Challenges in Carbon Capture 

and Storage. Environmental Science & Technology, 2011. 45(20): p. 8597-8604.

17. Stauffer, P.H., et al., A system model for geologic sequestration of carbon dioxide.

Environmental Science and Technology, 2009. 43(3): p. 565-570.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

C-1

Appendix C.

Poster Abstracts
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

C-2

Sustainable Water Treatment, Recycling & Disposal Practices 

in the Marcellus Shale Basin

Matthew J. Bruff

Altela, Inc.

The statements made during the workshop do not represent the views or opinions of EPA.

The claims made by participants have not been verified or endorsed by EPA.

Introduction

Recent technological innovations in hydraulic fracturing (well-stimulation) have transformed the 

nation’s shale formations from marginal producers of natural gas to substantial contributors to 

the nation’s energy supplies. At the same time, critical water resource problems have developed 

with respect to managing, treating and disposing of the significant volumes of hydraulic 

fracturing flowback waters in an environmentally safe manner. 

The Marcellus Shale is a thick sequence of Devonian age, sedimentary rocks in the Appalachian 

Basin that extends from southern New York across Pennsylvania, and into western Maryland, 

West Virginia, and eastern Ohio. Each Marcellus shale-gas well is hydraulically fractured with 

approximately five million gallons of water. Following fracturing of each well, significant 

amounts of hydraulic fracturing flowback water come to the surface and must be managed and 

disposed of in an environmentally responsible manner1. Historically in the Marcellus Shale, 

natural gas exploration and production companies have relied on either trucking the water to 

reinjection wells in Ohio where geologic formations support such high volume reinjection or 

sending the wastewater to commercial treatment facilities including publically owned treatment 

works (“POTWs”) to dilute this wastewater before releasing it into surface water bodies. There 

are many pollutants of concern in this hydraulic fracturing water which contains significant 

amounts of salt, metals, sulfates, and chlorides. In addition, certain constituents that are 

proprietary in nature are not fully disclosed on manufacturer’s safety data sheets. 

In response to these concerns, the Pennsylvania Department of Environmental Protection (“PA 

DEP”) developed new discharge standards. The PA DEP amended its Chapter 95 Wastewater 

Treatment Requirements effective August 21, 2010, to ensure that drinking water, waterways, 

and watersheds in the state were not impacted by high levels of total dissolved solids (“TDS”) 

including chlorides and sulfates2. These new discharge and recycling regulations have created 

challenges for the shale-gas industry due to the lack of proven treatment technologies that are 

able to economically treat hydraulic fracturing water to discharge water quality standards. 

Without such technological solutions, these new regulations may have the unintended 

consequence of curtailing the nation’s natural gas development through increased exploration 

and production costs. 

The purpose of this abstract is to provide a brief summary and update on efforts these past three 

years to develop an integrated water treatment technology solution for sustainable water resource 

management in the Marcellus Shale Basin. 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

C-3

Discussion 

NETL Project DE-FE0000833

The U.S. Department of Energy’s (“DOE”) Office of Fossil Energy’s, National Energy 

Technology Laboratory’s (“NETL”) primary goal is to enhance the responsible development of 

domestic natural gas and oil resources that supply the country’s energy. A specific objective is to 

accelerate the development and demonstration of technologies that will aid our country’s 

independent producers in dealing with use and treatment of water related to natural gas and oil 

production. 

In 2009, NETL selected nine new projects targeting environmental tools and technology for 

shale gas production. Altela, Inc. was selected as the lead team member with respect to Project 

DE-FE0000833 titled “An Integrated Water Treatment Technology Solution for Sustainable 

Water Resource Management in the Marcellus Shale”. The purpose of the field demonstration 

project was to provide an integrated approach aimed at addressing the increasing water resource 

challenges between natural gas production and other water stakeholders in shale gas basins. 

Specific goals of the project included: 1) deliver field-proof that the water treatment technology 

and protocol was actually capable of treating this highly challenged Marcellus hydraulic 

fracturing water to water quality standards required for discharge and/or applicable beneficial reuse, 2) deliver field-proof that the water treatment technology could economically treat the 

hydraulic fracturing water at a cost equal to or lower than current disposal methods, and 3) 

demonstrate that the regulatory environment would support implementation of the water 

treatment technology solution. 

The NETL field demonstration project successfully attained its goals. During nine continuous 

months of operation, the AltelaRain®system placed adjacent to a natural gas well treated 77 

percent of the hydraulic fracturing flowback and production wastewater on-site, providing 

distilled water as the product. The average treated water cost per barrel over the demonstration 

period was approximately 20 percent lower than the previous total conventional disposal costs at 

the site. The system also significantly reduced the need for trucking wastewater from the site 

thereby reducing truck mileage. Based on field data generated from the NETL demonstration, 

Altela increased the efficiency of its technology by more than 30%. All of the clean water 

produced at the demonstration site was suitable for beneficial re-use by well operators for 

additional stimulations and was also suitable to be discharged to surface waterways, thus 

reducing the economic and environmental impacts of clean water usage. Additional detailed 

information including complete water analyses, recovery rates and overall economics are 

included in the project’s final report dated June 30, 20113.

This DOE demonstration project accelerated the commercialization of the AltelaRain®system 

which has led to the development of several large centralized wastewater treatment, recycling 

and disposal facilities in the Marcellus including Casella-Altela Regional Environmental 

Services, LLC McKean Facility. 

Casella-Altela Regional Environmental Services, LLC (“CARES”)

In August 2011, Casella Waste Systems, Inc. and Altela, Inc. formed a joint venture, CasellaAltela Regional Environmental Services, Inc., to construct and operate water treatment, recycling 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

C-4

and disposal (“TRD”) facilities to support the natural gas drilling activity. The first facility is 

located in Sergeant Township near Mt. Jewett, Pennsylvania. The CARES McKean TRD 

Facility, (“CARES McKean Facility”)4is part of a larger initiative to transform the existing 

McKean County Landfill into a multi-purpose environmental services facility designed to serve 

the region's evolving recycling and disposal needs, create jobs, and reduce truck traffic. By colocating adjacent to a landfill and leveraging existing infrastructure, the CARES McKean 

Facility serves as a model for integrated and sustainable wastewater treatment, recycling, 

disposal and management in shale basins. 

One of the sustainability attributes of this co-gen facility is its ability to convert methane gas 

produced from the landfill into usable energy required for the wastewater treatment and 

desalination circuit. Designed to beneficially use landfill gas (“LFG”), the CARES McKean 

Facility employs LFG fired boilers to generate steam for the AltelaRain®thermal distillation 

circuit. In this manner, the facility’s energy operating costs are significantly reduced while also 

reducing certain air emissions from the LFG flare. The facility currently uses approximately 350 

standard cubic feet per minute of landfill gas with an average methane content of approximately 

52%. The methane gas is chilled prior to sending it in the transmission pipeline to the CARES 

facility using a multistage centrifugal blower. The landfill gas is regulated into either of two 9.8 

million BTU low pressure steam boilers at roughly 2 psi. The boiler manifolds were modified to 

support beneficial use of the landfill gas.

By utilizing this landfill gas, the thermal distillation circuit becomes economically viable to 

allow for TDS and related salt removal of the wastewater to support an open-loop facility. 

Following desalinization, the treated water meets NPDES requirements for discharge into the PA 

Commonwealth’s surface water bodies when recycling demand falls below supply. Without this 

open loop capability, out-bound water must be generally removed at the same rate as inbound 

wastewater in order to not reach storage constraints. 

Facility Description

The CARES McKean Facility has approximately 13 full and part-time employees and operates 

24/7 in varied shifts according to water acceptance demands. The 4-bay covered truck load-out 

area is designed for maximum receiving efficiency, convenience and ease of the driver. The 

facility has two 550,000 gallons storage tanks as well as three water storage impoundments. See 

site layout illustration below. 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

C-5

Figure 1. CARES McKean Site Plan

The wastewater entering the facility is processed through a variety of process systems, the first 

being a pre-treatment system that will yield Pretreated Frac Water (“PFW”). The PFW has two 

paths that it can take depending on the needs of the customer and the facility. The first path is to 

an outside storage facility where the PFW is mixed with Distilled Water (“DW”) to produce 

Certified Frac Water (“CFW”) for the customer to pick up for recycling. The second path for the 

PFW is to the AltelaRain®evaporation-condensation modules, which yields two liquid streams. 

The first stream which is the clean DW stream is as described above. The second steam which is 

the Concentrate Water (“CW”) stream is the residual liquid solution remaining after 

approximately 80% of the pure H2O has been removed via the recycling process. This residual 

CW solution will contain nearly 100% of the salt products, by weight that was contained in the 

original volume of Produced Water (“PW”) processed through the facility in a 24-hour period of 

time. 

Similar to nature's process for making rain, the AltelaRain®technology operates at low 

temperatures and low-grade steam. Ambient air flows up through brackish water in an 

evaporation chamber to strip contaminants into a concentrate. The air is then combined with 

steam and pushed down through a condensation chamber creating a clean distilled water product. 

The AltelaRain®technology does not require pressure which translates into lower OpEx and 

CapEx costs. As noted above, the process can be driven by low-grade heat, waste heat or natural 

gas thereby making it suitable for "co-generation" applications to reduce energy costs. 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

C-6

Figure 2. AltelaRain®Schematic

The clean DW produced during the recycling process is made available for beneficial re-use by 

oil and gas producers in on-going drilling operations, as make-up water for the boilers, or 

discharged, via the CARES McKean Facility’s approved NPDES permit. The residual CW, is reused as regulations permit (recycling, heavy brine water or road salt), can be solidified and 

disposed of as a solid waste in the landfill, or can be removed from the site and transferred to 

approved commercial produced water disposal facilities. Initial capacity of the facility is 500,000 

gallons per day (“GPD”) of PFW and 100,000 GPD of DW. See the general process schematic 

and floor plan figures below. The facility’s recycled hydraulic fracturing water can be supplied 

with varying level of customer-defined limits of removal of TSS, iron, barium, calcium, 

chlorides, TDS, sulfates, friction reducers, surfactants, biocides, radionuclides, etc. In this 

manner, valuable recycled water-based products can be offered to industry including recycled 

hydraulic fracturing water for reuse in hydraulic fracturing, clean distilled water and heavy brine 

for winterization. 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

C-7

Figure 3. CARES McKean General Process Schematic Overview

Figure 4. CARES McKean Floor Plan

Other capabilities of the facility include 1) separation and solidification services, 2) material 

sourcing including hydraulic fracturing sand supply, gravel for well-pad construction, and tanker 

cleaning and 3) storage and transportation services including interim water storage, centralized 

transportation network of rail and over-the-road trucking, and storage areas for lay-down yards.

Regulatory & Environmental Summary

The CARES McKean TRD Facility is a fully permitted centralized commercial wastewater 

treatment facility with the following primary permits: PA DEP WMGR123NW005 General 

Permit for the Processing and Beneficial use of oil and gas liquid waste, National Pollution 

Discharge Elimination System (“NPDES”) discharge permit PA0102288 (as amended), 

including attendant Water Quality Management Plan Part II Permit, and related PA DEP air
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

C-8

quality regulatory approvals. Following PA DEP’s recent Chapter 95 regulatory changes, the 

CARES McKean TRD facility’s technology is capable of meeting the required discharge 

requirements. These discharge requirements are summarized below:

Table 1. NPDES Discharge Requirements of Representative Outfall

NPDES 

CONSTIUENTS

Final 

Outfall 

001*

UNIT NPDES 

CONSTIUENTS

Final 

Outfall 

001*

UNIT

CBOD (avg mo) 48.5 mg/L TSS (avg mo) 11.3 mg/L

AmoniaNitrogen (avg mo) mg/L Uranium Report ug/L

" May 1-Oct 31 (avg mo) 2.1 Vanadium (avg mo) 0.0518 mg/L

" Nov 1-Apr 30 (avg mo) 6.3 Acetophenone (avg mo) 0.0562 mg/L

Arsenic (avg mo) 0.0102 mg/L 2-Butanone (avg mo) 1.85 mg/L

Barium (avg mo) 10 mg/L Carbazole (avg mo) 0.276 mg/L

Bromide Report mg/L Fluoranthene (avg mo) 0.0268 mg/L

Cadmium 0.0002 mg/L o-Cresol (avg mo) 0.561 mg/L

Chloride (avg mo) 250 mg/L n-Decane (avg mo) 0.437 mg/L

Chromium (avg mo) 0.0522 mg/L n-Octadecane (avg mo) 0.302 mg/L

Copper (avg mo) 0.0092 mg/L Phenol (avg mo) 1.08 mg/L

Gross Alpha Report pCi/L Pyridine (avg mo) 0.182 mg/L

Lead (avg mo) 0.0032 mg/L Osmotic Pressure (avg 

mo) 51.3 mOs/kg

Nickel (avg mo) 0.053 mg/L 2,4,6-Trichlorophenol 

(avg mo) 0.0018 mg/L

Oil & Grease (avg mo) 15 mg/L Acetone (NPDES (avg 

mo) 3.5 mg/L

pH 9-Jun SU Total Antinomy (avg 

mo) 0.0057 mg/L

Radium-226 + 228 Report pCi/L

Bis(2-

Ethylhexyl)Phthalate 

(avg mo)

0.0015 mg/L

Selenium (avg mo) 0.0051 mg/L Butyl Benzyl Phthalate 

(avg mo) 0.035 mg/L

Silver (avg mo) 0.0024 mg/L Total Cobalt (avg mo) 0.0194 mg/L

Strontium (avg mo) 10 mg/L Total Mercury (avg mo) 0.00005 mg/L

Tin (avg mo) 0.0367 mg/L p-Cresol (avg mo) 0.164 mg/L

Titanium (avg mo) 0.00612 mg/L Zinc (avg mo) 0.078 mg/L

TDS (avg mo) 818 mg/L

Numerous environmental controls are in place to ensure environmental protection and best 

business practice management including: 

Site Inspections: PA DEP inspects the facility on a periodic basis. Regular visual inspections are 

carried out by CARES employees monitoring levels within the on-site impoundments 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

C-9

Groundwater: Due to the site proximity to the adjacent McKean County Landfill, there is an 

established groundwater monitoring system with protocols approved by PA DEP under the 

landfill solid waste permit. 

Stormwater: The site has stormwater management controls in-place and approved by PA DEP. 

Spill Control: The facility has an approved PA DEP Pollution Prevention Contingency Plan 

outlining the spill control and prevention measures. 

Radiation Monitoring: The facility is equipped with stationary radiation monitors which screen 

each incoming truck to confirm that incoming loads do not exceed the facility’s radiation 

thresholds. Trucks exceeding the minimum radiation thresholds are not accepted at the facility.

Conclusions

Safe, reliable and cost effective water treatment is a key requirement for natural gas drilling 

companies. Developing the CARES McKean Facility near the Marcellus drilling activity and 

providing a safe and reliable option for treating and recycling the water reduces long-hauls to 

deep well injection sites and enables a back-haul of clean distilled water for beneficial re-use. 

This co-generation facility utilizing landfill gas to economically purify wastewater to discharge 

standards can set an environmental sustainability example for hydraulic fracturing water 

treatment and recycling in other emerging shale basins.

Acknowledgements 

Funding for NETL Project DE-FE0000833 was provided by U.S. Department of Energy’s Office 

of Fossil Energy. Project participants included Altela, Inc., Argonne National Laboratory, CWM 

Environmental and BLX, Inc. CARES McKean is a joint venture between Casella Waste 

Management Systems, Inc. and Altela, Inc. 

References

1. Soeder, Daniel J. and Kappel, William M.- U.S. Geological Survey (USGS-2009) USGS 

Fact Sheet 2009-3032 Water Resources and Natural Gas Production from the Marcellus 

Shale. http://pubs.usgs.gov/fs/2009/3032/pdf/FS2009-3032.pdf

2. PA DEP eLibrary-Chapter 95 – Total Dissolved Solids Statements of Policy Defining the 

Term “Authorization”.pdf 853-810-001.

http://www.elibrary.dep.state.pa.us/dsweb/Get/Document-86113/385-0810-001.pdf

3. National Energy Technology Laboratory-An Integrated Water Treatment Technology 

Solution for Sustainable Water Resource Management in the Marcellus Shale DEFE0000833 Final Scientific/Technical Report.

http://www.netl.doe.gov/technologies/oil-gas/publications/ENVreports/fe0000833-finalreport.pdf

4. Casella-Altela Regional Environmental Services, LLC www.caresforwater.com
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

C-10

Feasibility of In Situ Sequesteration of Toxic Metals in 

Flowback Water from Hydraulic Fracturing.

Andrew G. Stack

Oak Ridge National Laboratory

The statements made during the workshop do not represent the views or opinions of EPA. The 

claims made by participants have not been verified or endorsed by EPA.

Synopsis

Hydraulic fracturing is playing a dramatically increased role in natural gas and oil 

production in the United States (1,2), but environmental issues are currently delaying its 

development, e.g., the moratorium on hydraulic fracturing in the state of New York. 

Dissolved barium is one of the most significant toxic contaminants in produced brines 

from oil and gas operations, including water recovered during hydraulic fracturing of 

shales and sandstones (3,4). Radium is the primary NORM (Naturally Occurring 

Radioactive Material) in these fluids (5,6). Barite (BaSO4) ‘scales’ in wellhead and 

borehole equipment are radioactive due to radium incorporation (4) and above-ground 

barite precipitation has been employed as a treatment process for both contaminants (7). 

One possible method to significantly reduce the toxicity and radioactivity of produced 

waters and equipment could be to induce precipitation of contaminant as impurities in 

minerals directly in the subsurface geologic formations. 

The focus of this poster is to discuss what would work would need to be done to evaluate 

the feasibility of in situ radium-containing barite. Specific issues include: a) the 

efficiency of impurity metal incorporation under subsurface conditions in the presence of 

hydraulic fracturing fluids; b) the effect of pore-confinement in geologic media on the 

rates and locations of barite precipitation and permeability of the formation; and c) the 

applicability of models for predicting the performance of in situ precipitation schemes.

Significance

Subsurface fluids produced as wastewater in hydraulic fracturing activities, particularly 

from shale formations, are resulting in significant amounts of produced toxic and 

radioactive metal contaminants (3-7). Some natural gas wells in the Marcellus shale (PA) 

are producing up to 18,000 pCi/L dissolved radium (Ra2+) (8), whereas the U.S. EPA 

Safe Drinking Water Act Maximum Contaminant Limit (MCL) for this metal is 5 pCi/L. 

Barium (Ba2+) is a toxic metal often present in produced oil and gas field waters at levels 

of several thousand mg/L (8,4), far exceeding the EPA MCL of 2 mg/L (10-4.8 Molar). 

A novel strategy to reduce the concentration of contaminants such as radium and barium 

in produced waters in oil and gas fields is to promote the precipitation of a mineral phase 

that contains the toxic and/or radioactive contaminants directly in the subsurface. This 

method has been proposed for other subsurface contaminants such as uranium (9,10) and 

strontium (11,12). Due to the very low solubility of barite, dissolved Ba2+ concentrations 

below the EPA MCL may be achieved if dissolved SO4

2-

concentrations above ~10 mg/L 

can be maintained in the pore waters during the period of water recovery. It has already 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

C-11

been shown that incorporation of Ra2+ and Ba2+ as a major constituent or impurity in the 

highly-insoluble mineral barite (BaSO4) may be an effective potential strategy for aboveground post treatment (7,13). A more desirable approach would be to induce the 

precipitation of barite in situ in the subsurface production zone prior to or during 

flowback water production, as this would avoid bringing contaminated water to the 

surface. However, there is a significant gap in our fundamental understanding of how to 

predict and control the precipitation of barite in rock pores. The size distribution of pores 

in which the precipitation reactions preferentially occur is particularly poorly understood. 

This is important because using in situ precipitation as a sequestration method requires 

engineering the precipitation to occlude pore spaces uniformly without immediately 

clogging the aquifer or screened intervals of production wells and blocking the flow of 

the fluids through the rock (14,15).

In order to better predict and control in situ barium and radium mineral trapping, one 

question to be dealt is how efficiently Ra2+ and Ba2+ can be co-precipitated, and how the 

sequestration conditions affect the rate of precipitation and the efficiency. Both Ra2+ and 

Ba2+ form sulfate salts that are orders of magnitude less soluble than other common 

sulfate minerals such as gypsum (CaSO4•nH2O) (16). Although RaSO4 is only slightly 

less soluble than BaSO4 at room temperature, the concentration of Ba2+ in produced 

waters is much higher than Ra2+. Therefore it is reasonable to attempt to drive 

incorporation of Ra2+ into the barite crystal structure during its precipitation as a means 

of significantly reducing the concentrations of both species without precipitating other 

phases. Early free-drift studies(17-19) found that for the pure Ba-Ra-SO4 system, the 

reduction of Ra2+ concentration in solution correlates with the reduction in Ba2+. 

However, these studies did not yield a quantitative, predictive capability, nor did they 

account for competition by Ca2+, Sr2+ and other dissolved ions (Na+, Cl-) or compounds 

abundant in typical flowback water. Electrolyte composition and concentration can affect 

the kinetics of barite precipitation (20) and substantial amounts of incorporating ions 

(e.g., Ca2+, Sr2+ in barite) can inhibit the growth of a mineral (12,21). A field study of 

uranium mill tailings showed that the mobility of Ra2+ is entirely dominated by a 

disordered (Ra,Ba)SO4 barite phase (19). The solubility of this phase will be slightly 

higher than either of the two ideal end-member sulfates but it is not likely to exceed more 

than approximately 1.3-1.6 orders of magnitude that of pure barite (22), so it still will be 

only sparingly-soluble relative to other common sulfate minerals. In the long term, 

sulfate-reducing bacteria present in the (reducing) shale subsurface environment may 

reduce sulfate in the precipitated barite to sulfide, but release of radium and barium has 

not been shown to be substantial in the short term as a result of this process (23). Lastly, 

the scale inhibitors that are added to the hydraulic fracturing fluid inhibit growth of a 

minerals. Since in the proposed in situ precipitation strategy requires precipitation in 

situ, scale inhibitors should likely not be used and scale formation by other compounds 

besides sulfates (e.g., CaCO3) will need to be evaluated.

In addition to demonstrating that Ra2+ concentration can be efficiently reduced by coprecipitation in solutions containing much higher levels of Ba2+, Sr2+ and Ca2+, we need 

to develop an understanding of how pore size distribution, pore surface chemistry (e.g., 

shale mineralogy, surface coating by hydrocarbons, etc.) affects the sites and extent of 
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

C-12

barite precipitation in porous geologic media, while avoiding hindering or stopping fluid 

flow. The main constituents of shales are quartz, clays, and organics, although some 

shales also contain sizeable amounts of carbonates and other minerals. The distribution of 

barite between pores and exposed surfaces of these minerals is currently unknown but 

can be studied ex- and in-situ by X-ray and neutron scattering, using both synthetic 

model substrates as well as drill core samples from shale gas production sites. Finally, 

our ability to predict and control precipitation in the subsurface depends in part on 

applying a kinetics model measured in the laboratory under well-mixed conditions to a 

porous medium in the subsurface. Traditional geochemical kinetics models consider the 

rate of growth or dissolution of a mineral as a function of the saturation state of the 

system, but these models have been shown inadequate to describe reaction rates when the 

ratio of the aqueous form of the mineral’s constituent ions deviates from that to which the 

model was calibrated (11,24). An alternative is a “process-based” model that is built from 

reactions thought to occur on the mineral surface itself (25-27). Our recent work on 

calcite (CaCO3), has resulted in a process-based kinetics model that is suitable for direct 

inclusion into a reactive transport simulation used in porous media (28), which it may be 

possible to adapt to the Ra-Ba-SO4 system.

References

1) MIT Report (2011) The Future of Natural Gas.

2) National Petroleum Council Report (2011) Prudent Development: Realizing the 

potential of North America’s abundant natural gas and oil resources, Library of Congress 

Control #2011944162.

3) Veil, J.A., Puder, M.G., Elcock, D., Redweik, R.J. (2004) A white paper describing

produced water from production of crude oil, natural gas, and coal bed methane, Argonne 

National Laboratory Report, prepared for the U.S. Department of Energy under contract 

W-31-109-Eng-38.

4) Haluszczak, L.O., Rose, A.W., Kump, L.R. (2012) Geochemical evaluation of 

flowback brine from Marcellus gas wells in Pennsylvania, USA, Geochim. Cosmochim. 

Acta, DOI [10.1016/j.apgeochem.2012.10.002].

5) Rowan, E.L., Engle, M.A., Kirby, C.S., Kraemer, T.F. (2011) Radium content of oiland gas-field produced waters in the Northern Appalachian Basin (USA): Summary and 

Discussion of Data, U.S. Geological Survey Scientific Investigations Report 2011-5135.

6) Smith, K.P. (1992) An overview of naturally occurring radioactive materials (NORM) 

in the petroleum industry, Argonne National Laboratory Report ANL/EAIS-7.

7) Gregory, K.B., Vidic, R.D., Dzombak, D.A. (2011) Water management challenges 

associated with the production of shale gas by hydraulic fracturing, Elements, 7, 181-186.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

C-13

8) Urbina, I. (2011) "Regulation Lax as Gas Wells’ Tainted Water Hits Rivers" New 

York Times, Feb. 26, 2011.

9) Wright, K. E.; Hartmann, T.; Fujita, Y. (2011) Inducing mineral precipitation in 

groundwater by addition of phosphate. Geochem. Trans. 12:8.

10) Salome, K. R.; Green, S. J.; Beazley, M. J.; Webb, S. M. Kostka, J. E. Tailleferet, M. 

(2013) The role of anaerobic respiration in the immobilization of uranium through 

biomineralization of phosphate minerals. Geochim. Cosmochim. Acta, 106, 344-363.

11) Gebrihiwet, T. A.; Redden, G. D.; Fujita, Y.; Beig, M. S.; Smith, R. W. (2012) The 

Effect of the CO3

2-

to Ca2+ Ion activity ratio on calcite precipitation kinetics and Sr2+

partitioning. Geochem. Trans. 13:1. 

12) Bracco, J. N.; Grantham, M. C.; Stack, A. G. (2012) Calcite growth rates as a 

function of aqueous calcium-to-carbonate ratio, saturation index, and inhibitor 

concentration: Insights into the mechanism of reaction and poisoning by strontium. Cryst. 

Growth Des. 12, 3540-3548.

13) Curti, E. et al. (2010) "Radium uptake during barite recrystallization at 23 ± 2 °C as a 

function of solution composition: An experimental 133Ba and 226Ra tracer study" 

Geochim. Cosmochim. Acta, 74, 3553-3570.

14) Hornberger, G. M.; Mills, A. L.; Herman, J. S. (1992) Bacterial transport in porous 

media: Evalution of a model using laboratory observations. Water Resourc. Res., 28, 

915-938.

15) Borgia, A.; Pruess, K.; Kneafsey, T. J.; Oldenburg, C. M.; Pan, L. (2012) Numerical 

simulation of salt precipitation in the fractures of a CO2-enhanced geothermal system. 

Geothermics, 44, 13-22.

16) Frenier,W.W.; Ziauddin, M. "Formation, Removal, and Inhibition of Inorganic Scale 

in the Oilfield Environment" Society for Petroleum Engineers: Richardson, TX, 2008.

17) Germann, F.E.E. (1921) Adsorption of radium by barium sulfate, J. Am. Chem. Soc., 

43, 1615-1621.

18) Gordon, L., Rowley, K. (1957) Coprecipitation of radium with barium sulfate, Anal. 

Chem., 29, 34-37. 

19) Doerner, H., Hoskins, W. (1925) Co-precipitation of radium and barium sulfates, J. 

Am. Chem. Soc., 47, 662-675.

20) Becker, U.; Risthaus, P.; Bosbach, D.; Putnis, A. (2002) Selective attachment of 

monovalent background electrolyte ions and growth inhibitors to polar steps on sulfates 

as studied by molecular simulations and AFM observations. Molec. Sim. 28, 607-632.
EPA’s Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: 

Summary of April 18, 2013, Technical Workshop on Wastewater Treatment and Related Modeling

C-14

21) Wasylenki, L. E.; Dove, P. M.; Wilson, D. S.; De Yoreo, J. J. (2005) Nanoscale 

effects of strontium on calcite growth: An in situ AFM study in the absence of vital 

effects. Geochim. Cosmochim. Acta, 69, 3017-3027. 

22) Martina, A. J.; Crusiusb, J.; McNeea, J. J.; Yanfulc, E. K. (2003) The mobility of 

radium-226 and trace metals in pre-oxidized subaqueous uranium mill tailings. Appl. 

Geochem., 18, 1095-1110

23) Phillips, E. J. P.; Landa, E. R.; Kraemer, T.; Zielinski, R. (2001) Sulfate-reducing 

bacteria release barium and radium from naturally occurring radioactive material in oilfield barite. Geomicrobiol. J., 18, 167-182.

24) Stack, A. G.; Grantham, M. C. (2010) Growth Rate of Calcite Steps as a Function of 

Aqueous Calcium-to-Carbonate Ratio: Independent Attachment and Detachment of 

Calcium and Carbonate Ions. Crys. Growth Des., 10 (3), 1409-1413.

25) Larsen, K.; Bechgaard, K.; Stipp, S. L. S. (2009) The effect of the Ca2+ to CO3

2-

activity ratio on spiral growth at the calcite {10-14} surface. Geochim. Cosmochim. 

Acta, 74, 2099.

26) Nielsen, L. C.; DePaolo, D. J.; DeYoreo, J. J. Self-consistent ion-by-ion growth 

model for kinetic isotopic fractionation during calcite precipitation. Geochim. 

Cosmochim. Acta (2012) 86, 166-181.

27) Wolthers, M.; Nehrke, G.; Gustafsson, J. P.; Van Cappellen, P. (2012) Calcite growth 

kinetics: Modeling the effect of solution stoichiometry Geochim. Cosmochim. Acta, 77, 

121.

28) Bracco, J. N.; Steefel, C. I.; Stack, A. G. (in prep.) Bridging the Gap: Upscaling 

AFM Results From the Meso- to Macro- scales.
C-15

Wastewater Made Clear with Green Technology

Patricia Werner-Els

Advanced Waste & Water Technology

The statements made during the workshop do not represent the views or opinions of EPA. 

The claims made by participants have not been verified or endorsed by EPA.

Introduction

Electrocoagulation is the scientific discipline of utilizing electricity as the electromotive force to 

drive chemical reactions in a solution, suspension, or emulsion. A special form of direct current 

is introduced into the aqueous stream as it passes between predetermined electrodes in the 

electrocoagulation module. This energy from the electricity is the engine or driving force to shift 

the equilibrium of a reaction to less than equilibrium levels, thus providing a mechanism for 

removing dissolved, suspended or emulsified molecules, elements or ions to very minute levels 

in an aqueous stream.

Background

Electrochemical treatment can precipitate dissolved heavy metals by a combination of oxidation 

reduction reaction that in many cases produces oxide crystals that are very stable. Hexavalent 

chromium is reduced to trivalent chromium and removed as a precipitate. Copper, Lead, Zinc, 

Nickel and other metals are oxidized into oxide crystal form and can sometimes be concentrated 

and removed from the sludge stream to be recycled. Some metals require an anion to be present 

to form a precipitate such as calcium, magnesium, molybdenum, and others. Many times this

anion may already be present in the waste stream, but if not, it can generally be added very 

easily. These heavy metallic crystals can be a positive nucleus to attract the electron rich 

hydroxide floc and colloidal solids into a settle able precipitate. This precipitate can then be 

separated in a settling pond or in a clarifier after some of the heavy metals are classified and 

concentrated.

Electrocoagulation will break colloidal suspensions, which allows the precipitation and removal 

of suspended particles. The excess of electrons causes the colloidal particles to attract to a 

sacrificed metallic cation, which comes from the electrodes as the electric current passes through 

the electrode in accordance with Faraday's Law. This metallic cation acts as a nucleus to attract 

the electron laden colloidal particles together into a floc precipitate. This generates a larger 

heavier floc, which can then be separated by a secondary separation process such as settling, 

clarification or centrifugation.

Electrocoagulation will break oil emulsions and release the tied up emulsified oil to float to the 

surface where it can be skimmed off with a vacuum and recovered if viable. Oil becomes 

emulsified as shearing action from pumps or chemicals cause an open or broken bond in the 

hydrocarbon chain, which then attaches itself with a weak bond to the water molecule. Even 

though this is a weak bond, it is a protected bond and consequently very difficult to break by 

conventional means. As the electricity passes through the water being treated, electrons and 

energy are available as well as hydrogen ions or protons from the electrolysis of the water itself, 
C-16

and oxygen or hydroxide ions as a chemical feed stock for reaction completion. These 

subsequent reactions cause the weak bond to be broken and the oils to return to being a complete 

molecule and the emulsion is broken. At this point the oil again becomes hydrophobic and 

generally floats to the surface due to differences in specific gravity.

The Process

Electrochemical treatment is generally used on industrial waste streams to allow the reuse or 

discharge of an industrial waste stream. The process uses electricity rather than expensive, 

dangerous, and sometimes toxic chemicals to remove contaminants. Electrochemical treatment 

can be a pretreatment for other processes such as reverse osmosis, or a polish treatment for 

traditional treatment processes.

How Does Electrocoagulation Technology Work?

Electrocoagulation is the process of destabilizing suspended, emulsified or dissolved 

contaminants in aqueous medium by introducing a direct electrical current into the medium. The 

electrical current provides electromotive force to drive the chemical reactions.

When reactions are driven or forced, the elements or compounds will approach the most stable 

state. Generally, this state of stability produces a solid that is either less colloidal or less 

emulsified (or soluble) than the compound at equilibrium values. As this occurs, the 

contaminants form hydrophobic entities that precipitate and can easily be removed by a number 

of secondary separation techniques. Electrocoagulation neutralizes ions and particle charges, 

thereby allowing contaminants to precipitate. Colloids are then destabilized and aggregated and 

subsequently removed by sedimentation or filtration.

Under current wastewater treatment methods, a cocktail of chemicals is needed to treat large 

amounts of wastewater producing increased amounts of solids, which increase production costs 

and can create environmental problems when they are ultimately disposed. The negative impact 

on the environment is high using existing treatment methods. 

Electrocoagulation can often neutralize ions and particle charges, thereby allowing contaminants 

to precipitate. Colloids can be destabilized and aggregated and subsequently be removed by 

sedimentation or filtration. The amount of solids is substantially much less and environmentally 

friendly. 

This technology has been proven as one the most effective methods to treat large amounts of 

wastewater. The range of treatment is between 300 liters/hour to 600,000 liters/hour, depending 

on the site-specific requirements.

Electrocoagulation systems are part of a comprehensive treatment plan, as 75% of the water 

treatment is completed by this technology. For the remaining 25%, additional polishing systems 

would be added to meet the state and local discharge requirements.
C-17

For a range of wastewater treatment needs, electrocoagulation technology is a viable option. The 

technology itself has been successfully used for decades. The need for increased usage now is to 

help preserve and reuse our natural water resources. Droughts, natural disasters, municipal water 

needs and shale gas recovery will continue to put increased strain on our water resources and 

existing treatment facilities. 

For states in the western United States, electrocoagulation technology has had positive 

environmental impact while solving many existing concerns of wastewater and hydraulic 

fracturing fluid treatment. States such as Texas, Wyoming and Colorado have successfully used 

electrocoagulation technology for the treatment of a wide-range of industrial wastewater –

including hydraulic fracturing water. 

Results

Analytical testing has been done on a wide range of waste streams including municipal water, 

animal/dairy waste, and drilling/hydraulic fracturing fluids. The following table reflects some 

results on raw and electrocoagulation treated water from a hydraulic fracturing site located in 

Texas.

Constituents Units Raw Treated % reduction

Calcium, Ca mg/L 3,000 4.04 99.9

Magnesium, Mg mg/L 637 0.78 99.9

Sodium, Na mg/L 13,100 64.4 99.5

Potassium, K mg/L 313 2.56 99.2

Iron, Fe (total) mg/L 23 0.02 99.9

Bicarbonate, HCO3 mg/L 490 20 95.9

Chloride, Cl mg/L 28,000 97 99.7

Sulfate, SO4 mg/L 141 0.404 99.7

Sulfide, S mg/L 0.65 0.020 96.9

Boron, B mg/L 19.8 1.91 90.4

Barium, Ba mg/L 2.89 0.0032 99.9

Silica, SiO2 mg/L 65.6 0.546 99.2

Strontium, Sr mg/L 249 0.261 99.9

Totals (Sum) 46,042 171.93 99.6

Total Dissolved Solids mg/L 53,400 202 99.6

Calculated 

Hardness,CaCO3

mg/L 10,100 13.3 99.9

Total Alkalinity mg/L 490 20 95.9

Sodium Chloride, (total) mg/L 41,100 161.4 99.6

Sodium, Na (Calculated) mg/L 13,100 64.4 99.5

pH 6.14 7.3
C-18

Conclusions

Electrocoagulation is a technology that can be used in a variety of processes, is a “green” 

technology and may also produce beneficial by-products. Results indicate that water from a 

waste stream can be cleaned to most required discharge limits or reuse levels. 
C-19

Oil and Gas Water Purification using 

Switchable Polarity Solvent Forward Osmosis (SPS-FO) 

Aaron D. Wilson, Frederic F. Stewart, Mark L. Stone

Idaho National Laboratory, Biological and Chemical Processing

The statements made during the workshop do not represent the views or opinions of EPA. 

The claims made by participants have not been verified or endorsed by EPA.

Introduction

Oil and gas waters are very challenging feed solutions which vary greatly depended on source 

but often contain high total dissolved solid (TDS) in the form of salts and organics, suspended 

oils and solids, and feature a non-neutral pH. To apply reverse osmosis (RO) to oil and gas water 

feed solutions usually requires substantial pretreatment to prevent fouling and is only applicable 

to feed solution with a TDS below 47,000 ppm given RO practical limit of 70,000 ppm for it 

concentrate output.1Electrochemical methods such as reverse electrodialysis (RED) do not 

remove uncharged organics and are historically limited to brackish water (<8,000 ppm TDS) 

because of their relationship between processing cost and salinity.1 Distillation can treat high 

TDS but it is a mature field and has substantial cost; distillation is generally double the cost of 

RO for seawater desalination. An alternative is forward osmosis (FO) which moves water from a 

feed solution across a semi-permeable membrane to a draw solution based on an osmotic 

pressure differential.2 A forward osmosis (FO) process in which the osmotic draw solute is 

removed by means other than RO has the potential to address high TDS feed solutions. Such a 

next generation FO system would require a minimal amount of pretreatment when compared to 

competing methods and could have a significantly lower cost than distillation and RO. 

A number of next generation draw solutes have been explored including dissolved gases, 

hydroscopic organics, nanoparticles, inorganic salts, thermosensitive solutes, and thermolytic 

solutes. Each of these can each be removed by distillation or precipitation with the addition of 

salt mixtures, pH adjustments, temperature adjustments, or application of a magnetic field.3–18

Each of these systems has serious drawbacks, such as limited osmotic pressure and flux rate, 

limited recyclability, loss of the draw solute through diffusion through the FO membrane, and 

overall systems cost that have hindered their implementation. 

Switchable polarity solvents (SPS)

19–22, mixtures of carbon dioxide, water, and tertiary amines 

(Figure 1), are presented as viable forward osmosis (FO) draw solutes allowing a novel SPS-FO 

process.23 In this study substantial osmotic strengths of SPS are measured with freezing point 

osmometry and were demonstrated to induce competitive fluxes at high salt concentrations on a 

laboratory-scale FO unit utilizing a flat sheet cellulose triacetate (CTA) membrane. Under the 

experimental conditions the SPS degrades the CTA membrane; however SPS experiments with 

polyamide reverse osmosis (RO) membranes display greater stability towards SPS. Once the 

draw is diluted the major fraction of the switchable polarity solvent can be mechanically 

separated from the purified water after polar to nonpolar phase shift induced by introduction of 1 

atm carbon dioxide to 1 atm of air or nitrogen with mild heating. Trace amounts of SPS can be 

removed from the separated water with RO in a process that avoids solution concentration 
C-20

polarization. The separated nonpolar phase can be regenerated to a full strength draw and 

recycled with the re-addition of 1 atm of carbon dioxide.

Figure 1. A general example of an SPS from its nonpolar water immiscible 

form to its polar water miscible form.

An advantage of SPS-FO is the potentially low cost of operation, as compared to competing 

technologies that are reliant on expensive energy inputs from electricity, such as RO. SPS-FO 

functions at a fraction of the cost of other methods through a thermolytic cycle that avoids the 

distillation of water but still uses heat energy which costs a fraction of electrical energy. SPS-FO 

technology has the potential to address the water challenges presented by the most challenging 

produced water and flowback water feed solutions.

In addition a series of tertiary amines have been screened for their function as switchable polarity 

solvents (SPS). The relative ratios of tertiary amine and carbonate species as well as maximum 

possible concentration were determined through quantitative 1H and 13C NMR spectroscopy. The 

viscosities of the polar SPS solutions were measured and ranged from near water in the dilute 

systems through to the formation of a gel in specific systems at high concentrations. The van‘t 

Hoff indices for SPS solution were measured through freezing point depression studies as a 

proxy for the solutions osmotic strengths. A new form of SPS with an amine:carbonate ratio 

significantly greater than unity has been identified. Tertiary amines that function as SPS at 

ambient pressures appear to be limited to molecules with fewer than 12 carbons. 

RESULTS AND DISCUSSION

Initial SPS-FO Process Study

In their polar forms, many switchable polarity solvents (SPSs) form highly concentrated ionic 

solutions with substantial osmotic pressures that are well suited to act as a draw solute. For 

example, a 18.0 mol/kg (77 wt%) dimethylcyclohexylammonium bicarbonate [HN(Me)2Cy 

HCO3] solution is too concentrated to measure its osmolality through freezing point depression; 

however, diluted solutions can be measured as illustrated in Figure 2. Extrapolation from this 

dilute data predicts a fully concentrated 18.0 mol/kg [HN(Me)2Cy HCO3] solution has an 

osmotic strength of ~800 atm. This study used a 7.6 mol/kg [HN(Me)2Cy HCO3] draw solution 

with a projected osmotic pressure of ~335 atm, which at the time of the study was believed to be 

the maximum concentration of the [HN(Me)2Cy HCO3] solution.
C-21

Figure 2. Osmotic pressure measured through freezing point depression 

experiments based on (red squares) amine concentration and (blue 

diamonds) total solute amine and bicarbonate.

FO flux experiments were conducted to verify the osmotic pressure measured for the polar SPS 

with freezing point depression was accessible to drive osotic flux. Feed solutions of varying 

NaCl concentrations exposed to a 7.6 mol/kg [HN(Me)2Cy HCO3] draw solution across an HTI 

cellulose triacetate (CTA) FO membrane. Figure 3 presents the initial flux measured at each 

concentration. These initial results are promising with favorable flux observed through a 5.0 

mol/kg NaCl feed solution. A 5.0 mol/Kg NaCl feed solution is 10-times the concentration of 35 

salinity seawater with a 226,000 ppm TDS and an osmotic pressure of ~275 atm. Flux against a 

feed solution with a known ~275 atm osmotic pressure supports the projected ~335 atm for our 

7.6 mol/Kg draw solution and suggests that the full strength 18.0 mol/Kg draw solution (~800 

atm) should be able to pull water out of a fully concentrated sodium chloride solution (6.1 

mol/kg) which has an osmotic strength of ~340 atm.24 

Figure 3. Water flux using 7.6 mol/Kg [HN(Me)2Cy HCO3] draw solution 

against different concentrations of sodium chloride at 30°C, HTI CTA 

membrane in PRO mode (active layer draw solution).

y = 1.7274x - 0.0303

R2 = 0.9988

y = 0.8806x - 0.0303

R2 = 0.9988

0

0.5

1

1.5

2

2.5

3

3.5

4

0 1 2 3 4 5

Osm/Kg 

mol/Kg

0

5

1 0

1 5

2 0

2 5

3 0

3 5

0 1 2 3 4 5 6 flux (L/(M2hr)

NaCl (mol/Kg)
C-22

Conventional FO systems act primarily as pretreatment methods, homogenizing a water stream 

for ultimate purification through RO, or they must include their solute in the final product. An 

SPS-FO system is significantly different; FO is the primary water purification method in which a 

miscibility shift liberates the majority of the water from the draw. Once a draw solution is 

saturated with water or reaches a desired dilution, the carbon dioxide is removed from the 

solution driving a shift in the SPS to its nonpolar immiscible form, which phase separates from 

the water. The two phases then can be mechanically separated, resulting in water purified to 

greater than 98 wt% in a system using N(Me)2Cy (solubility 18 g/L). This switching process was 

demonstrated in Jessop’s initial report with the best result found using low grade heat of 60°C 

and a nitrogen purge.21

Trace amounts of SPS draw solute can be removed from the separated water through an RO 

process. This RO step is very different than the RO process involving a solution containing 

conventional solutes. During conventional salt RO, the volume of the feed solution is reduced as 

pure water is forced through the membrane, the reduction of volume corresponds to 

concentration polarization, which ultimately limits how much water can be obtained from the 

feed despite the application of pressures between 50 and 70 atm.25 At its 18 g/L solubility limit, 

N(Me)2Cy has a maximum osmotic pressure of 3.4 atm which it never exceeds. Thus, low 

osmotic pressure aids RO by minimizing required energy and pressure. An RO experiment 

conducted on a 16.7 g/L solution of N(Me)2Cy with a polyamide thin-film composite membrane 

achieved a stable 99.65% rejection of the organic over a 4-hour period to produce a solution with 

0.06 g/L N(Me)2Cy concentration.

A 0.06 g/L N(Me)2Cy concentration may be acceptable for some beneficial uses such as 

agriculture, microbial (algae) growth, solution mining, hydraulic fracturing water, and 

thermoelectric makeup water. There is no immediate toxicity concern from a 0.06 g/L solution at 

the oral LD50 rate of 425 mg/Kg, but it is likely still too high for human consumption over the 

long term. The RO treated water will need to be purified through an additional inline polishing 

step using an absorbent such as activated carbon.

Figure 4. Proposed SPS-FO water purification process.

The complete SPS-FO system illustrated in Figure 4 featuring six major components: an FO 

loop, carbon dioxide degasser, mechanical liquid separator, low pressure filtration cell (RO like), 

a finishing step such as a polishing column, and a gas contactor to recycle the SPS. In addition to 

these major items, there will be various pumps, heat exchangers, and holding tanks. The capital 

cost of this system is expected to be comparable to a double pass seawater reverse osmosis 
C-23

(SWRO) system. Based on current costs of heat ($3.00 MMBtu) and electricity ($0.10 kWh) and 

the capital cost the SPS FO system could cost half of SWRO per unit of water product while 

recovering a greater fraction of the water in a seawater feed >75% and economically treat higher 

concentration feeds. 

SPS-FO Comparison to Ammonia-CO2 Draw Solutions

There are other thermolytic draw solutes similar to the function of SPS most notably the 

ammonia-CO2 system actively developed since 2005.11–14 Fundamental theoretical energy

requirements for the SPS-FO are expected to be less than the ammonia-CO2 system (Table 1), 

however the real advantage is practical energy requirements. To sufficiently remove ammonia 

form water the ammonia-CO2 system must bring the aqueous solution near reflux regardless of 

the pressure.

15 In contrast preliminary experiment indicate that tertiary amines used in SPS 

effectively separate from water at much lower temperatures. Furthermore, both the draw and the 

feed solutions need to be heat stripped to remove ammonia in the ammonia-CO2 system due to 

the diffusion of ammonia from the draw solution into the feed solution.16 The tertiary amines 

used in SPS-FO are not expected to penetrate the FO membrane due to their greater molecular 

volume.

Table 1. Thermolytic draw solute energy requirements comparison.

Ammonia-CO2

kJ/mol

SPS-FO

kJ/mol

Carbamate decomposition

NR3HCO2NH2 → 2NH3(aq) + CO2(g)

72.3(X)

X = 0.1-0.8

0

Bicarbonate decomposition

NR3H2CO3 → NR3(aq) + CO2(g) + H2O

64.3(1-X)

1-X = 0.9-0.2

64.3*

NH3 heat of dissolution 30.5(1+X) ~0

Total 98.7 to 125.6 64.3

*X is the stoichiometric excess of NH3 used to maintain solute solubility.

Structure Function of Tertiary Amines for SPS-FO

A series of tertiary amines have been screened for their function as switchable polarity solvents 

(SPS).26 The relative ratios of tertiary amine and carbonate species as well as maximum possible 

concentration were determined through quantitative 1H and 13C NMR spectroscopy. A number of 

limitation on tertiary amines capacity to function as SPS have been identified. This includes a 

carbon:nitrogen ratio of 12:1 when working at ambient pressures. A non-osmotic form of SPS 

was also indentified, whose primary compositional feature is an amine to carbonate ratio greater 

than unity. These non-osmotic SPS systems dominate tertiary amines with a C:N ratio of 10:1 

through 12:1. The SPS that do function as osmotic SPS (C:N ratio of 6:1 through 8:1) have been 

demonstrated to be aggressive solvents that attack membranes as well as common polymers used 

in constructing water treatment systems. 

This chemical aggressiveness combined with the amines toxicities adds cost to any system 

designed around such tertiary amines. If the chemical aggressiveness the SPS can be addressed 

with existing membranes and materials then SPS-FO process is at a technological readiness level 

where the next step is an integrated lab-scale system followed by a pilot system. If the chemical 

aggressiveness cannot be overcome there are two promising research fronts for the selection of 
C-24

an optimal SPS for SPS-FO: 1) explore conditions that allow the tertiary amines with elevated 

C:N ratios to function as osmotic SPS and 2) exploration of SPS other than mono tertiary amines 

that are less toxic (nontoxic) and less chemically aggressive while still providing high osmotic 

pressures, low viscosity, and good phase transition behaviors at a reasonable cost. Based on our 

structure function study the SPS-FO process it should be possible to identify an optimal SPS and 

associated conditions for an effective SPS-FO process.

CONCLUSION

SPS draw solutes have been found to enable an entirely new SPS-FO process for purifying water 

and concentrating solutions. The osmotic pressure and FO water flux properties of SPS reported 

here are substantial; suggesting that high osmotic pressure feeds produced water may be 

dewatered using this method. The novel phase switching from a high osmotic pressure aqueous 

solution to purified water and a nonpolar liquid, which can be physically separated, is a 

potentially revolutionary advance.

ACKNOWLEDGEMENTS

This work was supported by the United States Department of Energy through contract DEAC07-05ID14517. Funding was supplied by Idaho National Laboratory via the Laboratory 

Directed Research and Development Fund (LDRD) and the Battelle Memorial Institute through 

Intellectual Property Development Fund (IDF). 

REFERENCES

(1) Jörg Drewes; Tzahi Cath; Jean Debroux; John Veil An Integrated Framework for Treatment and 

Management of Produced Water - Technical Assessment of Produced Water Treatment 

Technologies; Colorado School of Mines / Advanced Water Technology Center, 2009.

(2) Cath, T. Y.; Childress, A. E.; Elimelech, M. Forward osmosis: Principles, applications, and 

recent developments. Journal of Membrane Science 2006, 281, 70–87.

(3) George W. Batchelder United States Patent: 3171799 - Process for the demineralization of Water 

1965.

(4) David N. Glew United States Patent: 3216930 - Process for Liquid Recovery and Solution 

Concentration 1965.

(5) William Thomas Hough United States Patent: 3532621 - Process for Extracting Solvent from a 

Solution 1970.

(6) Frank, B. S. United States Patent: 3670897 - Desalination of Sea Water 1972.

(7) William Thomas Hough United States Patent: 3721621 - Forward-Osmosis Solvent Extraction 

1973.

(8) McGinnis, R. L. United States Patent: 6391205 - Osmotic desalinization process 2002.

(9) Noh, M.; Mok, Y.; Lee, S.; Kim, H.; Lee, S. H.; Jin, G.; Seo, J.-H.; Koo, H.; Park, T. H.; Lee, Y. 

Novel lower critical solution temperature phase transition materials effectively control osmosis 

by mild temperature changes. Chem. Commun. 2012, 48, 3845–3847.

(10) James E. Miller; Lindsey R. Evans SAND2006-4634 Forward Osmosis: A New Approach to 

Water Purification and Desalination; Sandia National Laboratory, 2006.
C-25

(11) McCutcheon, J. R.; McGinnis, R. L.; Elimelech, M. A novel ammonia--carbon dioxide forward 

(direct) osmosis desalination process. Desalination 2005, 174, 1–11.

(12) McCutcheon, J. R.; McGinnis, R. L.; Elimelech, M. Desalination by ammonia-carbon dioxide 

forward osmosis: Influence of draw and feed solution concentrations on process performance. 

Journal of Membrane Science 2006, 278, 114–123.

(13) Ray A. Neff United States Patent: 3130156 - Solvent Extractor 1964.

(14) McGinnis, R. L.; Elimelech, M. Energy requirements of ammonia-carbon dioxide forward 

osmosis desalination. Desalination 2007, 207, 370–382.

(15) Hancock, N. Engineered Osmosis for Energy Efficient Separations: Optimizing Waste Heat 

Utilization FINAL SCIENTIFIC REPORT DOE F 241.3 DE-EE0003467; 2013.

(16) McGinnis, R. L.; Hancock, N. T.; Nowosielski-Slepowron, M. S.; McGurgan, G. D. Pilot 

demonstration of the NH3/CO2 forward osmosis desalination process on high salinity brines. 

Desalination 2013, 312, 67–74.

(17) Ge, Q.; Su, J.; Chung, T.-S.; Amy, G. Hydrophilic Superparamagnetic Nanoparticles: Synthesis, 

Characterization, and Performance in Forward Osmosis Processes. Ind. Eng. Chem. Res. 2010, 

50, 382–388.

(18) Ling, M. M.; Wang, K. Y.; Chung, T.-S. Highly Water-Soluble Magnetic Nanoparticles as Novel 

Draw Solutes in Forward Osmosis for Water Reuse. Ind. Eng. Chem. Res. 2010, 49, 5869–5876.

(19) Jessop, P. G.; Heldebrant, D. J.; Li, X.; Eckert, C. A.; Liotta, C. L. Green chemistry: Reversible 

nonpolar-to-polar solvent. Nature 2005, 436, 1102.

(20) Jessop, P. G.; Phan, L.; Carrier, A.; Robinson, S.; Durr, C. J.; Harjani, J. R. A solvent having 

switchable hydrophilicity. Green Chem. 2010, 12, 809–814.

(21) Jessop, P. G.; Kozycz, L.; Rahami, Z. G.; Schoenmakers, D.; Boyd, A. R.; Wechsler, D.; 

Holland, A. M. Tertiary amine solvents having switchable hydrophilicity. Green Chem. 2011, 

13, 619–623.

(22) Jessop, P. G.; Mercer, S. M.; Heldebrant, D. J. CO2-triggered switchable solvents, surfactants, 

and other materials. Energy Environ. Sci. 2012, 5, 7240–7253.

(23) Stone, M. L.; Rae, C.; Stewart, F. F.; Wilson, A. D. Switchable polarity solvents as draw solutes 

for forward osmosis. Desalination 2013, 312, 124–129.

(24) Wilson, A. D.; Stewart, F. F. Deriving osmotic pressures of draw solutes used in osmotically 

driven membrane processes. Journal of Membrane Science 2013, 431, 205–211.

(25) Desalination of Seawater; American Water Works Association, 2011.

(26) Wilson, A. D.; Stewart, F. F. Structure-Function Study of Tertiary Amines as Switchable 

Polarity Solvents. manuscript in preparation 2013.