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## Overview of Hydraulic Fracturing Wastewater Research
Technical Workshop Series: Wastewater Treatment and Related Modeling

Cynthia Sonich

- Mullin & Christopher A. Impellitteri EPA

- Research Triangle Park • April 18, 20131 

## EPA Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources

EPA Study Goals:

• 

### Assess the potential impacts of hydraulic fracturing on drinking water
resources

• 

### Identify the driving factors that affect the severity and frequency of any impacts



## For more information: http://www.epa.gov/hfstudy2 

# Hydraulic Fracturing Water Cycle

WATER CYCLE STAGES Water Acquisition → Chemical Mixing → Well Injection → Flowback and Produced Water → Wastewater Treatment and Waste Disposal Water Acquisition Chemical Mixing

Well Injection Flowback and Produced Water Wastewater Treatment and Waste Disposal

Surface Water Ground Water Wellhead Recycling Facility

Disposal Well Wastewater Treatment Plant3 

# Primary Research Questions

Water Treatment and Waste Disposal 

### Water Acquisition

Chemical Mixing

Flowback and Produced Water



### Well Injection How might large volume water withdrawals from ground and surface water impact drinking water resources?

What are the possible impacts of releases of flowback

and produced water on drinking water resources? What are the possible impacts of the injection and fracturing process on drinking water resources? What are the possible impacts of releases of hydraulic fracturing fluids on drinking water resources ?

What are the possible impacts of inadequate treatment of hydraulic fracturing wastewaters on drinking water resources? Research Questions4 What are the potential impacts from surface water disposal of treated hydraulic fracturing wastewater on drinking water treatment facilities? What are the common treatment and disposal methods for hydraulic fracturing wastewater and where are these methods practiced?

How effective are conventional POTWs and commercial treatment systems in removing organic and inorganic contaminants of concern in hydraulic fracturing wastewater? Literature Review Wastewater Treatability Studies Literature Review Well File Review FracFocus Analysis

Literature Review Surface Water Modeling Source Apportionment Studies Brominated Disinfection By

- Product Precursor Studies Secondary Research Questions Research Projects 

# Secondary Research Questions5 

# Types of Research Projects

Analysis of Existing Data

Literature

Review

Spills Database Analysis

Service Company Analysis

Well File Review

FracFocus

Analysis Scenario Evaluations

Subsurface

Migration Modeling

Surface Water Modeling

Water Availability

Modeling Laboratory Studies

Source Apportionment Studies

Wastewater Treatability

Studies

Brominated Disinfection By

Product Studies

Analytical

Method Development Toxicity Assessment Case Studies

Retrospective Case Studies

Prospective Case Studies

4/18/20136 

### Objective: Collect information on wastewater treatment and disposal from hydraulic fracturing operations to inform project plans and interpretations of results 

# Literature Review **Analysis of Existing Data**

Research Progress

• Evaluate information on wastewater treatment and disposal from hydraulic fracturing operations from existing papers and reports, focusing on peer

- reviewed literature

• Follow procedures identified in study plan

Next Step

• Continue to review and assess literature related to wastewater treatment and disposal according to research questions in the study plan7 

### Objective: Assess well construction and hydraulic fracturing operations as reported by nine oil and gas operators Research Progress

• Well

- specific records:

o Provided by nine oil and gas operators (includes confidential business information)

o Includes hydraulic fracturing wastewater treatment and disposal practices for 332 wells hydraulically fractured in 2009 and 2010

• Extraction of available data from the well files is underway Next Steps

• Work with oil and gas operators to clarify information provided

• Analyze data to address research questions 

# Well File Review

**Analysis of Existing Data**8 

### Objective: Collect information on water volumes and sources as reported by oil and gas companies

Research Progress

• Extracted data, checked for quality issues, and organized in a database for analysis

• Developed draft queries to address research questions

Next Steps

• Analyze water usage

• Summarize data by water source or type 

# FracFocus Analysis **Analysis of Existing Data**9 

# Wastewater Treatability **Laboratory Studies**

Commercial Treatment Systems

• 

### Field studies

• 

### Collect influent, effluent, and residuals samples

• 

### Analyze concentrations of VOCs, SVOCs, anions, metals/inorganics, TDS, radionuclides Wastewater Treatment Facility/Biological Processes

• 

### Bench studies with chemostat reactors

• 

### Blend hydraulic fracturing wastewater with synthetic municipal wastewater

• 

### Collect influent and effluent samples

• 

### Monitor effects on biological processes within wastewater Objective : Assess effectiveness of wastewater treatment processes on selected chemicals found in hydraulic fracturing wastewater10 

### Objective : Identify possible concentrations of selected chemicals at public water system intakes downstream from wastewater treatment facilities

• 

### Collect model inputs from the National Pollutant Discharge Elimination System monitoring reports and USGS stream water quality and flow rate data

• 

### Use three modeling approaches to determine potential bromide and radium levels downstream 1) Steady

- state mass balance model
2) Transient empirical model
3) Hybrid empirical

- numerical model

• Run models with different discharge scenarios and stream flow scenarios based on data collected 

# Surface Water Modeling

**Scenario Evaluations**

Monte Carlo simulation used to estimate uncertainty in output

Confirm results with USGS tracer data and EPA Water Quality Simulation Package11 

### Objective : Identify proportion of hydraulic fracturing wastewater that may impact public water system intakes downstream from wastewater treatment facilities 

# Source Apportionment **Laboratory Studies**

Sample Analyses

• Field studies on two rivers

• Collect samples upstream and various distances downstream from discharge

• Analyze samples for suite of elements and ions including strontium 87/86 ratios 

### Modeling

• Compare two rivers using peer

reviewed models

• Identify and quantify contaminant source types using receptor models

• Receptor models include Unmix

, Positive Matrix Factorization, Chemical Mass Balance12 Sample Drinking Water Intake 

### Discharge Point Discharge includes hydraulic

fracturing wastewater, coal

fired power plant effluents, mining effluent, and road salt

Sample Upstream ISCO Sampler

Sample Downstream Sample Discharge 

# Source Apportionment **Laboratory Studies**13 

### Total Trihalomethanes

• Focus on the formation of brominated trihalomethanes

• Bench studies

• Compare equimolar concentrations of bromide in spiked laboratory water and blended effluents

• Maintain chloride:bromide ratio found in effluents in spiked waters

• Eliminate chloride:bromide ratio as a variable 

# Brominated Disinfection By

Product Precursor Studies **Laboratory Studies**

Objective : Assess the contribution of hydraulic fracturing wastewater to formation of brominated disinfection by

- products at public water systems14 

# Discussion

Are there other sources of data and/or samples which could be obtained for further study?

What are the most important future research topics regarding wastewater management and water reuse?