NICHOLAS SCHOOL OF THE ENVIRONMENT | DUKE UNIVERSITY

Wastewater Generation and 

Disposal from Natural Gas 

Wells in Pennsylvania

 

By 

Aurana Lewis 

 

Dr. Martin Doyle, Adviser 

May 2012 

Masters Project submitted in partial fulfillment of the 

requirements for the Master of Environmental Management degree in 

the Nicholas School of the Environment of 

Duke University
 i

Abstract 

The recent boom in natural gas production in Pennsylvania has generated huge volumes of 

wastewater. Key drivers have been a combination of high prices for natural gas, advances in 

horizontal drilling, and hydraulic fracturing; a technique used to explore ‘unconventional’ gas 

formations. Using data gathered by the Pennsylvania Department of Environmental Protection, 

the volumes of waste generated and waste disposal methods were examined. 

Comparing wastewater and gas production from unconventional natural gas exploration in the 

Marcellus shale (hereafter ‘Marcellus wells’), and conventional natural gas (hereafter 

‘conventional wells’) found Marcellus wells were more efficient, producing approximately three 

times more natural gas per gallon of wastewater. Waste composition was similar between the 

two well types, but Marcellus wells produced an average of 1.355 million gallons (Mgal) of waste 

and 1,301 million cubic feet of natural gas (MMcf) over four years compared with an average of 

0.120 Mgal of waste and 32.2 MMcf from conventional wells for the same timeframe. While the 

Marcellus wells are more efficient, the unconventional drilling has created a boom in natural gas 

production in the northeast, dramatically increasing wastewater generation. 

A timeline looking at regulatory changes over this period, and the resulting shifts in disposal 

options, showed a transition from historical disposal methods, relying heavily on dilution, to the 

current framework relying on reuse, injection wells and advances in dissolved solid treatments. 

With growth expected in to continue in Pennsylvania and to spread to the neighboring states of 

West Virginia and Ohio, waste generation will continue increasing in the northeastern region. 

Based on this assessment of waste generation, disposal options, and future growth, the 

northeast needs to focus on improving wastewater recycling and advanced wastewater 

treatment options that remove dissolved constituents prior to disposal. Given the ecological 

damage seen as shale gas expanded into the northeast and the regulatory restrictions that have 

been created, well operators in the northeast must develop a system of reuse and treatment for 

wastewater if shale gas is to continue expanding.

 
 ii

Table of Contents 

Introduction: ..................................................................................................................................... 1 

History of Hydraulic Fracturing .................................................................................................. 4 

Outline of Topics ........................................................................................................................ 5 

Methods: .......................................................................................................................................... 7 

Section I: Waste Composition and Production ................................................................................. 9 

Drilling Fluids .............................................................................................................................. 9 

Fracturing Fluid and Brine ........................................................................................................ 11 

Brine ......................................................................................................................................... 14 

Basic Sediment/Spent Lubricant/Servicing Fluid ..................................................................... 16 

Gas production ......................................................................................................................... 16 

Section I – Conclusions on Waste Volume Production ............................................................ 18 

Section II: Waste Disposal Options and Utilization: ....................................................................... 20 

A Timeline of Waste Disposal from PA Wells........................................................................... 22 

Publically Owned Treatment Works (POTWs): ..................................................................... 23 

Centralized Waste Treatment (CWTs): ................................................................................. 24 

The Wave of the Future ........................................................................................................ 25 

Underground Injection Wells ............................................................................................... 26 

Reuse .................................................................................................................................... 28 

Advanced CWT ...................................................................................................................... 31 

Section II - Conclusion .............................................................................................................. 34 

Future Concerns - Landfill Disposal .......................................................................................... 35 

Proposed State and Federal Regulatory Changes: ................................................................... 35 

Section III: Projections: ................................................................................................................... 36 

Conclusions: .................................................................................................................................... 38 

References: ..................................................................................................................................... 39 

 
 iii

List of Figures 

Figure 1 - United States wellhead prices for natural gas since 1973 (EIA 2012a). .......................... 1 

Figure 2 - Gas and oil production estimates from the Pennsylvania Department of Environment’s 

Oil and Gas Database (EIA 2011; EIA 2012b). .................................................................................. 2 

Figure 3 - Wastewater production from conventional and Marcellus wells from 2003 to 2011.1 . 2 

Figure 4 - Media coverage of the term “hydraulic fracturing” from a variety of sources............... 3 

Figure 5 – Shale gas plays in the United States, including the Marcellus shale in the northeast 

(EIA 2010). ....................................................................................................................................... 6 

Figure 6 - Drilling waste volumes produced from conventional and Marcellus wells. ................. 10

Figure 7 - Ratios of water, sand, and chemicals for slick-water fracture fluid (Arthur et al. 2008)

 ....................................................................................................................................................... 11 

Figure 8- A histogram of water use for hydraulic fracturing in Bradford County. It is unclear 

whether the wells were drilled vertically or horizontally (Frac Focus 2011). ............................... 12 

Figure 9- Fracking fluid volumes produced from Marcellus and conventional wells. ................... 13 

Figure 10 - Brine volumes from Marcellus and conventional wells for each year of production. 14 

Figure 11 - Gas production from Marcellus and conventional wells by year. ............................... 17 

Figure 12 – Cumulative breakdown of waste by type for conventional and Marcellus wells from 

2001 to 2011.................................................................................................................................. 18 

Figure 13- A four-year profile of waste production from Marcellus and conventional wells. ...... 19 

Figure 14 - Volumes of wastewater disposed at POTW facilities over time. ................................ 23 

Figure 15 – Volumes of wastewater disposed at CWT facilities though time. .............................. 24 

Figure 16 – Injection well disposal volumes of oil and gas wastewater through time. ................ 27 

Figure 17 – Volumes of wastewater reused from oil and natural gas though time. ..................... 30 

Figure 18 - The two pie charts show the overall disposal method for 2009 and 2011 respectively, 

with side bars indicating the disposal method by CWT facility. (PA DEP 2012; Veil 2010; Hapchuk 

2012). ............................................................................................................................................. 32 

Figure 19 - Waste disposal trends overtime for conventional and Marcellus wastewater. ......... 34 

Figure 20 – Estimates of natural gas resource extraction over the next 20 years (EIA 2012c). .... 36 
 iv

List of Tables 

Table 1 – Brine production by year for Marcellus and conventional wells. .................................. 15 

Table 2 - Contaminant levels for Marcellus wastewater and regulatory discharge standards. .... 16 

Table 3 – Gas production by year for Marcellus and conventional wells. .................................... 17 

Table 4 – A four-year profile of waste and gas production for an average Marcellus and 

conventional well. ......................................................................................................................... 20 

Table 5 – The maximum levels of constituents that could be present to reuse waste fluids for 

hydraulic fracturing mixtures in 2007. .......................................................................................... 28 

Table 6 – The maximum levels of constituents that may be present to reuse waste fluids for 

hydraulic fracturing mixtures in 2011. .......................................................................................... 29 

Table 7 – Factors for various advanced treatment options to remove TDS. ................................ 33 

 
 v

List of Acronyms 

Bbl Oil barrel (42 US gallons) 

Bcf Billions of cubic feet 

Bcfe Billions of cubic feet equivalent for natural gas 

Bgal Billions of gallons 

BOGM Bureau of Oil and Gas Management 

CWT Centralized waste treatment 

Mcf Thousands of cubic feet 

Mgal Millions of gallons 

MHF Massive hydraulic fractures 

MMcf Millions of cubic feet 

NETL National Energy Technology Laboratory 

NORM Naturally occurring radioactive material 

PA DEP Pennsylvania Department of Environmental Protection 

POTW Publically owned treatment works 

RCRA Resource Conservation and Recovery Act 

SGEIS Supplemental generic environmental impact statement 

TDS Total dissolved solids 

TSS Total suspended solids 
 1

Introduction: 

Global energy demands are rising at a time when known energy reserves are declining. The 

cost of energy for the consumer is on the rise (see Figure 1; EIA 2012a). With that rise have 

come innovative methods to extract energy from unconventional sources. In the oil and natural 

gas industry this has meant a shift from conventional drilling, in which gas is drawn from a 

porous reservoir, to more intensive methods of extraction like hydraulic fracturing (CAPP 2011). 

Hydraulic fracturing is the process of injecting large volumes of water, sand, and chemicals into 

low porosity formations at high pressure, creating fractures that facilitate the migration of gas 

to a wellbore for collection (US DOE 2009). This enhances the recovery of natural gas from 

organic-rich formations with low permeability, like shale, a fine-grained sedimentary rock. 

Figure 1 - United States wellhead prices for natural gas since 1973 (EIA 2012a). 

Hydraulic fracturing, in combination with advances in horizontal drilling and the rise of 

natural gas prices, has resulted in the exponential growth of gas production in Pennsylvania (See 

Figure 2; EIA 2011; EIA 2012b). Pennsylvania sits over the Marcellus shale, the largest shale gas 

deposit in the United States, with an estimated 494 trillion cubic feet of available natural gas (US 

DOE 2009). During the peak of gas prices, gas production rose from both conventionally drilled 

wells (hereafter ‘conventional wells’) and unconventionally drilled wells in the Marcellus shale 

(hereafter ‘Marcellus wells’). Coupled with this growth was a substantial increase in wastewater 

production. Between 2004 and 2011 wastewater volumes from oil and natural gas wells 

increased by a factor of four, from around 200 million gallons (Mgal) to around 800 Mgal 

annually (See Figure 3). 
 2

Figure 2 - Gas and oil production estimates from the Pennsylvania Department of 

Environment’s Oil and Gas Database (EIA 2011; EIA 2012b).1

Figure 3 - Wastewater production from conventional and Marcellus wells from 2003 to 2011.1

The arrival of hydraulic fracturing in the northeastern United States has caused a dramatic 

increase in media attention (See Figure 4), placing it center stage in energy discussions. 

President Obama encouraged the use of ‘American-made’ energy, citing shale gas in his 2012 

 

1

 Bcf – Billions of cubic feet, Mgal – Millions of gallons 
 3

State of the Union address as a cleaner energy alternative that will create jobs in America 

(Obama 2012). France recently banned hydraulic fracturing despite suffering from a natural gas 

shortage during the 2011-2012 winter (Pilgram 2012; Casert 2012). Poland has embraced 

hydraulic fracturing, leasing approximately 1.1 million acres of mineral rights and encouraging 

the development of shale gas resources (Natural Gas Europe 2011). Britain suspended the use of 

hydraulic fracturing when a direct link was found between the production enhancement 

technique and a series of low-level earthquakes in Blackpool, England (Vukmanovic 2011). 

Countries around the world are deciding between an energy future with the exploration of 

unconventional resources using hydraulic fracturing or banning the development of resources 

using the controversial technique. The outcome could be crucial, risking either poorly 

understood and potentially permanent environmental damage or declines in economic growth 

due to growing energy costs. 

Figure 4 - Media coverage of the term “hydraulic fracturing” from a variety of sources.2

The controversy surrounding hydraulic fracturing rests on a series of poorly understood 

environmental impacts. The extraction of natural gas through hydraulic fracturing may have 

 

2

 Articles were counted by going to the publications website and searching for “hydraulic fracturing” by 

year in the publications archive. 
 4

direct impacts on the environment (Zoback 2010), but some of the largest impacts are from the 

generation of large quantities of wastewater. Current conventional on-shore oil and gas 

activities generate an estimated 848 billion of gallons (Bgal) of wastewater per year (Clark and 

Veil 2009). At present it is unclear how hydraulic fracturing and the development of 

unconventional gas resources may alter the volumes of wastewater being generated. Disposal of 

wastewater is one of the largest challenges facing the natural gas industry (Clark and Veil 2009). 

History of Hydraulic Fracturing 

Hydraulic fracturing has been used in oil and gas production since the 1940’s, although only 

recently has hydraulic fracturing been widely used to develop unconventional shale gas 

resources (Economics and Martin 2007). In additional to higher prices, advances in hydraulic 

fracturing fluid mixtures and better horizontal drilling techniques have both decreased the costs 

and increased the effectiveness of these practices (Boyer et al. 2006; Economides and Martin 

2007), leading to a widespread development of unconventional resources. 

The most common hydraulic fracturing method currently in use, called slick-water hydraulic 

fracturing, was developed for the Barnett shale in Texas in the 1990’s (Economides and Martin 

2007; Paktinat and O’Neil 2011). It was not until the mid-1980s that operators began using 

massive hydraulic fractures (MHF) in the Barnett shale, which used a gel-based fluid (2,270 m3) 

and sand (635,000 kg) to open the fractures (Boyer et al. 2006). In 1997 the focus shifted to the 

use of slick-water techniques, which uses a much higher ratio of water to chemicals than gels. 

For modern hydraulic fractures the ratio used is between 11,000 m3

 to 19,000 m3 of water, 

1300-2300 kg of sand, and 110-190 m3

 of chemicals on average per well (US DOE 2009).3 While 

well performance was only slightly improved using slick-water mixtures, costs were 

approximately 65% lower, prompting an almost complete shift to slick-water fracturing (Boyer 

et al. 2006). 

The second important technological advance was the ability to utilize horizontal drilling to 

focus on specific rock formations. The thickness of a shale beds is generally only 100 to 600 feet, 

greatly limiting the effect hydraulic fracturing can have in vertical wells (US DOE, 2009). 

 

3

 The ratios of water, sand, and chemicals were calculated based on information from Modern Shale Gas:

a Primer (US DOE 2009). Sand density was assumed to be 2.6 Kg/m3. 
 5

Horizontal drilling, developed in the 1990’s, allows operators to follow the bedding of shale 

formations, greatly increasing the surface area of the formation in contact with the well (EIA, 

1993). In the late 1990’s the combination of slick-water hydraulic fracturing and horizontal 

drilling began to be used in shale gas extraction (EIA 1993; Boyer et al. 2006). The need to 

fracture horizontally drilled wells led to a third development, multi-stage fractures, where a 

small section of the well could be segregated from the rest of the well bore for fracturing. Each 

of these advances has increased the amount of gas that can be produced from previously 

unviable formations (Economides and Martin 2007). 

Gas production is greatest immediately following hydraulic fracturing and then declines 

steeply, with a 5 to 10 year period of viable production (King 2010). Re-fracturing, where an 

older well is hydraulic fractured again to increase production, is common when dealing with 

wells fractured using a gel-treatment. The older gel treatments were not as effective and refracturing has increased well production considerably (King 2010). Re-fracturing slick-water 

fractured wells was initially less successful (Boyer et al. 2006), but has not been dismissed (King 

2010). Research is being done to improve re-fracturing in slick-water fractured wells (Zoback et 

al. 2010). The ability to re-fracture wells will be important in determining how much water a 

well uses over the course of its life. The re-fracturing process would require a similar volume of 

water as the initial fracturing and would result in similar wastewater production. 

Outline of Topics 

The relative waste volumes generated from conventional and unconventional wells remain 

poorly understood. This paper will present an analysis of gas and wastewater production from 

unconventional wells drilled in the Marcellus Shale (‘Marcellus wells’) and conventionally drilled 

wells from Pennsylvania (‘conventional wells’). The Marcellus shale is located under 

Pennsylvania, New York, West Virginia, Ohio, and Maryland (See Figure 5, DOE 2009) with most 

of the current development in the Marcellus region is located in Pennsylvania (PA). 
 6

Figure 5 – Shale gas plays in the United States, including the Marcellus shale in the northeast 

(EIA 2010). 

In Section I, I will address differences in waste generation and relative efficiencies between 

conventional wells and Marcellus wells. I will examine disposal practices and the effects of 

regulation overtime in Section II. Pennsylvania is of particular interest because it faces unique 

challenges for wastewater disposal. In most natural gas producing regions, the majority of 

wastewater is disposed of through injection wells, which re-injects the waste into the deep 

geologic formations (Veil and Clark 2010a). Limited injection well capacity within Pennsylvania 

has led to the disposal of wastewater through a variety of surface methods (Johnson 2011). 

Realizing some of these disposal practices may pose a risk to drinking water supplies and aquatic 

ecosystems (Volz et al. 2012), Pennsylvania has made regulatory changes that force well 

operators to consider alternative methods of disposal. I present a timeline of waste disposal 

trends and demonstrate how regulatory changes have shifted the landscape of disposal, as well 

as identify potential future trends for waste disposal. 

Finally, I include a brief discussion of potential growth in shale gas drilling in the 

northeastern United States to evaluate future waste volumes in Section III. The study uses 
 7

current estimated waste production, trends in waste disposal, and future growth scenarios to 

consider options for Pennsylvania’s growing wastewater disposal needs. 

Methods: 

Data were downloaded from the PA DEP oil and gas reporting website. The PA DEP Bureau 

of Oil and Gas Management (BOGM) collects data on well production and waste volumes in 

accordance with PA law (25 PA §78.121). Well reports are due annually for all wells, including 

the production volumes of hydrocarbons, types and volumes of waste, and waste disposal or 

reuse information (25 PA §78.121(a)). Well location, well type, and operator identification 

information is collected at the time of drilling (25 PA§78.122). The collected data had several 

errors that needed to be addressed. The following discusses errors and corrections to the data 

prior to analysis. 

Information was collected annually from conventional well operators. Marcellus operators 

reported annually until March 2010, when a new law required reporting of Marcellus well 

production and waste volumes bi-annually (PA S.B. 297). Data from Marcellus wells were 

reported twice during the transition in the period from July 2009 to December 2009. Although 

the reported gas and waste records overlapped for this period, waste records were not 

duplicated in the reported data (Roger Dietz, PA DEP, personal communication). Gas production 

was duplicated over the period and required re-calculation. The database included days of 

production, allowing estimates of production in the overlapping period. 

The data contained numerous wells that reported no production of gas, oil or condensate. 

These wells were removed from the analysis, leaving the 2,240 Marcellus wells and 81,718 

conventional wells. 

Data were reported for each well by waste type and accepting disposal facility for each year. 

In a given year a well could produce multiple types of waste and deliver to multiple facilities, 

with separate entries for each waste type and facility. In cases where a single volume of 

wastewater was sent to multiple facilities, the volume of wastewater appeared to be overreported. Several wells recorded the same amount of waste for a single period going to multiple 

waste facilities, and, upon closer review, the total waste volumes for these records appeared 
 8

abnormally high. Considering reasons for this error, the most feasible explanation appears to be 

the total volume of waste was reported disposed to each facility, where in reality only a portion 

of the waste went to each facility. This would multiply the waste volume generated at any 

individual well by the number of facilities used, giving a falsely high waste volume. Given this 

assumption the waste amount was divided evenly between all the accepting facilities. The 

analysis looked for wells with identical waste volumes during individual periods (yearly or biyearly) being delivered to multiple facilities. For waste deliveries meeting these criteria, the 

waste volume was divided by the number of disposal facilities and this new volume was 

reported for each facility. 

The wells also reported a waste by type, classifying the waste by 8 residual waste codes 

defined by the Bureau of Waste Management (BWM 2001). Only 6 of the wastes refer to liquid 

waste, Brine, Drilling Waste, Fracking Fracking waste (sometimes called Frac Fluid), Basic 

Sediment, Servicing Fluid and Spent Lubricant Waste. A description of these waste types will be 

discussed in Section I. All waste types were assumed to be correctly identified in the reporting. 

For each waste record, the disposal facility name, address and geographic coordinates were 

provided. Additionally, operators reported a ‘Disposal Method’ indicating the type of facility 

receiving the waste. Several reported fields for disposal facilities had significant problems. 

Common errors included misspellings in the facility name, lack of location information, and 

multiple ‘disposal methods’ identified for a single facility. Clean-up of the data focused on 

correctly identifying Municipal Treatment Facilities or publically owned treatment works 

(POTW), centralized waste treatment facilities (CWT) and injection wells. Similar disposal facility 

names and geographic locations were checked against data gathered from Google Earth, the PA 

DEP, Argonne National Laboratory, and facility websites. 

After correcting the data, statistical analyses were performed to assess differences in 

wastewater volumes generated by conventional and Marcellus wells. Because the data were 

often non-normally distributed, comparisons were made using 95% bootstrapped confidence 

intervals. 

To create a timeline of waste disposal, overall waste disposal volumes were totaled by year. 

While some conventional wells also produce substantial quantities of oil, all conventional wells 
 9

were included in the analyses because they all produced varying amounts of natural gas and 

because the wastewater is disposed of using the same methods regardless of how much oil a 

well produces. The total volumes were analyzed by waste type and year, and compared with a 

discussion of regulatory changes in Pennsylvania. 

The waste data from 2007 was permanently lost by the PA DEP and was not available for 

this analysis. 

Section I: Waste Composition and Production 

Wastewater is produced continuously throughout drilling, fracturing, and production 

phases. At different stages the chemical composition of waste can vary greatly. The wastewater 

entered into the Pennsylvania DEP database is separated into 6 categories that indicate what 

part of the process the waste is produced in (BWM 2010). The following section will discuss how 

waste is generated, estimates of waste volumes, and consider general contaminants for each 

waste type. Although the following section will discuss how errors may occur in the labeling of 

waste, all of the waste labels are assumed to be correct for this analysis. 

Drilling Fluids 

The first type of waste is drilling fluid, also called drilling mud. Drilling fluid is used during the

drilling process to lubricate the drill bit, control any upwelling pressure in the well, and support 

the well bore while removing drill cuttings (Caen et al. 2012; NYSDEC 2011). There are a variety 

of potential drilling fluids that can be used by well operators, including air-based, water-based, 

petroleum-based and synthetic-oil (‘food-grade’) based drilling fluids (Caen et al. 2012). In 

Pennsylvania the surface area of the well, from the surface to 50 feet below fresh groundwater 

or 50 feet into consolidated rock (whichever is deeper), must be drilled with air, freshwater or 

freshwater based drilling fluid (25 PA § 78.83(a); 25 PA § 78.83(c)). Below this depth, there are 

no regulations requiring or banning the use of any particular type of drilling fluid, but 

petroleum-based drilling fluid is rarely used by industry due to environmental protection laws 

and costs (OH EPA 2012; Caen et al. 2012). However, the use of petroleum-based muds may 

occur in Marcellus shale drilling as they have recently been used in other shale gas fields (Mabile 

et al. 2011). 
 10

Figure 6 - Drilling waste volumes produced from conventional and Marcellus wells. 

On average, Marcellus wells generated more drilling fluid waste than conventional wells, 

with a mean drilling fluid disposal of 175,000 gallons ± 30,700 per Marcellus well. The range of 

drilling waste from conventional wells was much lower, with an average of 27,000 gallons ± 

1,600 per well. There are two possible explanations for the difference in waste volume from 

Marcellus and conventional wells. The first is depth. The Marcellus formation is one of deepest 

hydrocarbon formations in the area, lower than many of the conventional formations (Milici and 

Swezey 2006). An increase in drilling fluid would be expected from the deeper drilling required 

to reach the Marcellus formation. The second is the horizontal drilling used in many Marcellus 

wells, which extends the well bore.4

 As the length of the well bore increases, more drilling waste 

would be expected. Overall the confidence intervals for conventional and Marcellus drilling fluid 

volumes did not overlap, indicating that Marcellus drilling waste volumes were statistically 

larger than conventional volumes. 

This study assumes that similar drilling fluids are used for Marcellus and conventional wells, 

although it is unclear whether different formations would use the same type of drilling fluids 

 

4

 Marcellus data reported 2,758 wells listed as horizontally drilled with only 773 wells listed as vertical. 

Data reported for conventional wells listed 3,444 vertical wells and only 4 horizontal wells. 
 11

(Caen et al. 2012). The analysis of impacts unique to hydraulic fracturing for the supplemental 

generic environmental impact statement (SGEIS) prepared by the State of New York indicated 

that drilling fluid for hydraulically fractured wells was considered the same as historic drilling 

fluid types (NYSDEC 2011). Drilling muds may contain a number of hazardous contaminants, 

including heavy metals, organic pollutants, and hydrocarbons (Mall and Donnelly 2010). Drilling 

fluids are a one-time volume of waste, produced only during the creation of the well. 

Fracturing Fluid and Brine 

After drilling is complete, a well is ready for hydraulic fracturing stimulation. As previously 

described (See History of Hydraulic Fracturing) hydraulic fracturing is a water intensive process 

that produces large volumes of saline, chemically contaminated wastewater. Slick-water 

fracturing fluids are a mix of around 91% water, 7.5% sand and 0.50% chemicals (See Figure 7; 

Arthur et al. 2008). The specific composition of slick-water fluids differs between well operators 

and shale formations. 

Figure 7 - Ratios of water, sand, and chemicals for slick-water fracture fluid (Arthur et al. 2008) 

The amount of water needed to fracture a well is variable depending on the characteristics 

of the well and the geologic formation. The common range listed is 3 to 5 million gallons for a 

horizontal well in the Marcellus shale (US DOE 2009), but values as high as 9 million gallons have 

been reported (DAERS 2010). A survey of 158 voluntarily reporting wells drilled in Pennsylvania 

during 2010 and 2011 showed significant variability, with a mean volume of 4.8 Mgal and range 

from 0.9 to 8.4 Mgal (See Figure 8; FracFocus 2011). 
 12

Figure 8- A histogram of water use for hydraulic fracturing in Bradford County. It is unclear 

whether the wells were drilled vertically or horizontally (Frac Focus 2011). 

After the hydraulic fracturing process, the pressure in the well is reversed and a portion of 

the injected fluid is recovered. The second waste type, called flowback or fracking fluid, is 

considered to be the recovery of these fluids. Estimates of fracking fluid recovery range widely, 

with a national estimate of 10-70% of injected fluids (API 2010). Regional estimates for flowback 

volumes from the Marcellus shale are much lower with a range of 9-35%, however, data for 

these estimates are limited (NYSDEC 2011). Fracking fluid is generally recovered between 2 to 8 

weeks after the fracturing of the well is complete (NYSDEC 2011), but there are no specific rules 

regarding separation between fracking fluid and the later stage fluid called brine (BWM 2010; 

Adam 2012). Marcellus wells require hydraulic fracturing to be commercially viable, but 

conventional wells may also be fractured to improve performance (Economides and Martin 

2007; CAPP 2011). 
 13

Figure 9- Fracking fluid volumes produced from Marcellus and conventional wells. 

When comparing the two well types, Marcellus wells produce significantly more fracking 

fluid waste, around 460,000 gallons ± 46,000 on average, while conventional wells produce 

around 28,000 gallons ± 1,500. The increased volume of waste may be related to differences in 

fracturing method between the two wells, the depth of the formations, or the length of the 

wellbores due to horizontal drilling (Economides and Martin 2007; Milici and Swezey 2006). The 

confidence intervals for fracking fluid from the two well types do not overlap indicating the fluid 

volumes are statistically different. 

Like drilling fluid, fracking fluid is considered a one time volume of waste that occurs after 

hydraulic fracturing. While hydraulic fracturing may be repeated on the same well to increase 

gas production a second time, the re-fracturing time period is long enough (between 7-10 years) 

that no re-fracturing is expected to have occurred on wells from the Marcellus shale (Blauch et 

al. 2009; King 2010). If re-fracturing occurs, the volumes of waste are expected to be similar to 

the volumes of waste produced during the first fracturing job (King 2010). 

Fracking fluid many contain a wide variety of residual chemicals used during the hydraulic 

fracturing fluid (Colburn 2011). Fracking fluid is initially low in total dissolved solids (TDS) or 
 14

salts, naturally occurring radioactive material (NORM), and heavy metals similar to the fluid 

injected into the well. Overtime the fracking fluid becomes a saline brine through contact with 

the rocks and mixing with in situ formation fluids (Blauch et al. 2009). The shift from fracking 

fluid to brine, the final type of waste fluid produced, occurs gradually and with separation 

determined by the well operator (J. Adams, personal communication, March 8, 2012). 

Brine 

Brine is commonly produced in many types of oil and gas exploration (EPA 1987). In 

conventional wells brine is generally considered to originate from within the formation and is 

recovered during the gas production process (Veil 2004). For wells subject to hydraulic 

fracturing, brine may be a mix of naturally occurring liquid and some remaining hydraulic 

fracturing fluid. Brine can continue to flow for anywhere from 2 years after drilling to the end of 

the well’s life (Blauch et al. 2010). 

Figure 10 - Brine volumes from Marcellus and conventional wells for each year of production. 

For conventional wells, the number of gallons of brine produced decreased slightly over 

time (See Figure 10). The average brine produced during the first year of operation in 
 15

conventional wells was 26,500 gallons ± 2,140 and declined between 2,000 to 10,000 gallons 

each year for the first 4 years (Table 2). While other studies have observed increases in 

conventional well brine production in other regions through time, we observe a significant 

decline in conventional wells’ brine production in PA (Clark and Veil 2004). For Marcellus wells, 

the results showed a more extreme decline (See Figure 10). The average production declined in 

an exponential fashion, with 360,900 gallons ± 40,200 in the first year and only 19,730 gallons ± 

10,600 produced by the fourth year (See Table 2). A four-year profile is shown in Figure 10. This 

time period was chosen because there are few Marcellus wells reporting more than four years 

of data. 

Table 1 – Brine production by year for Marcellus and conventional wells. 

Brine tends to be highly saline, with salinity often more than twice seawater. Table 2 

displays a range of contaminants in brine samples from Marcellus shale wastewater (NYSDEC 

2011). Because fracking fluids and brine are difficult to differentiate and are often collected 

together, this range indicates the level of contaminants that may be present in fracking fluid, 

brine, or a combination of the two. Shown with the brine ranges are the requirements for 

contaminants from the BOGM and a new PA regulation, started in August 2010. Disposal of oil 

and gas waste has consistently required the removal of oil and grease, TSS, iron, and pH 

adjustment, shown in Table 2 (BOGM 2001). In 2010, PA created a new regulation to address 

common contaminants from oil and natural gas wastewater, including salts called total dissolved 

solids (TDS) (PA Ch. § 95.10). The new TDS regulations set discharge levels for TDS, chloride, 

barium, and strontium prior to disposal. These regulatory limits are shown in Table 2 to give an 

indication of ecologically protective levels for surface disposal. 

Brine Production in gallons First Year Second Year Third Year Fourth Year

Marcellus Mean 360,900 247,300 91,640 19,730 

Confidence Interval 40,200 62,700 25,400 10,600 

Conventional Mean 26,500 16,370 14,120 11,150 

Confidence Interval 2,140 1,140 1,300 1,030 
 16

Table 2 - Contaminant levels for Marcellus wastewater and regulatory discharge standards. 

a) NYSDEC 2011, b) BOGM 2001, c) PA § 95.10 

Basic Sediment/Spent Lubricant/Servicing Fluid 

These three fluids , basic sediment, spent lubricant, and servicing fluid, represent 0.039% of 

the total waste disposed for both conventional and Marcellus wells. The largest group is basic 

sediment, which is identified as “oil and gas production storage impurities/sediment”, amounts 

to a total of 1.08 Mgal since 2004 (BWM 2010). The next two groups, spent lubricant, composed 

of waste drilling lubricants, and servicing fluids, from maintenance or work over fluids, produced 

less than 0.5 Mgal of waste total since 2004. Because these fluid types are minimal, no 

discussion of contaminants or specific disposal options will be presented. 

Gas production 

Typically, natural gas production from shale gas, like Marcellus wells, shows an exponential 

decline curve (King 2010). While conventional wells can have more stable gas production 

overtime, impacted by various actions taken by the well operator, shale gas wells produce gas at 

a rate set by the fracturing in the well. Figure 11 (below) shows the rate of gas production from 

Marcellus and conventional wells in Pennsylvania. 

Range (mg/L) Median (mg/L)

pH 0 - 8.5 6.6 6 - 8

TDS 1,530 - 337,000 63,800 500

TSS 16 - 2,080 129 30

Chloride 287 - 228,000 56,900 250

Barium 0.553 - 15,700 1,450 10

Iron 0 - 810 29.2 3.5

Oil and Grease 5 - 1,470 17 15

Strontium 0.501 - 5,841 1,115 10

Analysis

Maximum Discharge 

Levelb,c (mg/L)

Marcellus (WV and Northern PA)a
 17

Figure 11 - Gas production from Marcellus and conventional wells by year. 

Considerably more gas was produced from Marcellus wells relative to conventional wells, 

especially in the first two years. The first year is typically not a complete calendar year and, 

therefore, volumes for year one are likely underestimated. Thus the slight increase in the 

second year for both Marcellus and conventional wells may have resulted because the second 

year is the first full year of production. After the first full year, Marcellus wells show an 

exponential decline over time, where conventional wells have only a small decrease in gas 

production. Table 3 shows the average gas production for the two well types by year of 

production. 

Table 3 – Gas production by year for Marcellus and conventional wells. 

Gas Production in Mcf First Year Second Year Third Year Fourth Year

Marcellus Mean 396,100 439,600 138,700 56,510 

Confidence Interval 25,900 35,100 17,900 14,600 

Conventional Mean 7,019 10,090 8,223 6,650 

Confidence Interval 304 376 1,056 2,720 
 18

Section I – Conclusions on Waste Volume Production 

The total volumes of waste production are calculated both as cumulative waste and as the 

average waste produced from individual Marcellus and conventional wells. Figure 12 shows the 

breakdown of the cumulative waste volume by type of waste for wells from 2001 to 2011. The 

first Marcellus wells were drilled in 2004, so no waste was produced from Marcellus wells until 

2004. Conventional wells are dominated by brine production (86.9%), with only a small amount 

of fracturing fluid (8.2%) and drilling fluid (4.7%). Marcellus wells are a combination of brine 

(46.8%), fracturing fluid (37.7%) and drilling fluid (15.4%), with brine slightly dominating. These 

profiles are an amalgamation of waste from wells of different ages, so they will not reflect the 

waste profile for an individual well. 

Figure 12 – Cumulative breakdown of waste by type for conventional and Marcellus wells 

from 2001 to 2011. 

For individual wells, overall waste volume is very different between Marcellus wells and 

conventional wells, while waste composition is only slightly different if both wells types are 

hydraulic fractured. Figure 13 shows a four-year profile of waste from an average Marcellus well 

and an average conventional well. The creation of this profile assumes drilling, fracking fluid, 

and brine waste are generated by both of the two well types. While Marcellus wells would be 

expected to have all three waste fluids at every well, conventional wells do not always use 
 19

hydraulic fracturing and may not generate fracking fluid waste (Economides and Martin 2007). 

Because few of wells in the PA DEP database report all three fluid types, these profiles are based 

on the three separate mean volume estimates of the different waste types. 

Figure 13- A four-year profile of waste production from Marcellus and conventional wells. 

In figure 13, the pie charts are sized to show the difference in the amount of waste 

production, with Marcellus wells producing approximately 11.3 times more waste per well than 

conventional wells. However, as shown in Table 4, Marcellus wells also produce approximately 

40 times more gas in 4 years on average than conventional wells. As a result Marcellus wells are 

significantly more efficient than conventional wells in terms of waste production, with about 

three times as much gas produced for each gallon of wastewater. This ratio may go down 

slightly over time as gas production from hydraulically fractured wells decreases, but even with 

no gas production beyond the fourth year and steady brine production mirroring the fourth year 

brine values, Marcellus wells remain more efficient than conventional wells. 
 20

Table 4 – A four-year profile of waste and gas production for an average Marcellus and 

conventional well. 

The difference in waste production between the two wells types is important because the 

increase in Marcellus drilling quickly increased waste volumes to record levels. However, the 

increased efficiency means gas production is increasing more rapidly than waste production. 

Figure 2 and Figure 3 showed the increased gas production and the increased waste production 

respectively. Pennsylvania dramatically increased its production of natural gas producing 10 

times more natural gas in 2011 than 2004, with only 4 times more waste production. 

Section II: Waste Disposal Options and Utilization: 

As waste production in Pennsylvania has increased, disposal options were also changing 

rapidly, with various disposal options gaining favor as regulations shift. There are four major 

options for well operators to handle wastewater. 

The first is publically owned treatment works (POTWs), which are generally municipal or 

county wastewater treatment facilities designed to handle household sewer flows. These plants 

have historically accepted mostly brine, but also fracturing fluid and drilling wastes. POTWs are 

designed to remove biological contaminants and some heavy metals using filtration, 

coagulation, settling ponds and a purifying step like chlorine or ultra-violet light (Veil 2010b). 

The second option is centralized waste treatment (CWT) facilities, which are private 

commercial wastewater treatment operations that handle industrial waste. These facilities have 

handled all the types of waste fluids produced from oil and gas operations. CWT facilities may 

use a wide variety of treatment options, but historically have not addressed dissolved 

contaminants (Veil 2010b). 

Waste Type Marcellus (Mgal) Conventional (Mgal)

Drilling 0.175 0.027

Frac Fluid 0.460 0.028

4-yr Brine Total 0.720 0.068

4-yr Waste Total 1.355 0.120

4-yr Gas Total 1,031 (MMcf) 32.2(MMcf)
 21

The third option is injection wells, where waste is injected into a deep subsurface formation 

for permanently disposal. Injection wells are not impacted by waste type or contaminants 

during disposal. 

The fourth option is recycling, where wastewater is blended with fresh water and hydraulic 

fracturing chemicals for use in subsequent hydraulic fracture treatments. Recycling is growing in 

popularity, but has limitations on the amounts of TDS, barium and other contaminants that can 

be present for the waste to acceptable for reuse in hydraulic fracturing fluids (NYSDEC 2011). 

Recycling waste is easiest when it has low concentrations of TDS and heavy metals, such as 

fracturing fluid, but may also be used for brine or drilling fluid if the waste is treated. 

In choosing disposal options it is important to note that these waste fluids are being handled 

and disposed of as non-hazardous waste, although in some cases the wastes may contain 

hazardous materials that pose a risk to human health (EPA 1987). The hazardous materials 

present in wastes are regulated under the Resource Conservation and Recovery Act (RCRA), 

which classifies waste as hazardous (subtitle C) or non-hazardous (subtitle D) (40 CFR Part 261). 

Although oil and gas waste fluids often contain contaminants that are considered hazardous or 

may have hazardous characteristics, Congress specifically exempted these wastes from a 

hazardous classification in the Solid Waste Disposal Act Amendments section 3001(b)(2)(A) (EPA 

1987; SWDA 3001(b)(2)(A)). 

The implications of this exemption for waste disposal from oil and gas exploration are 

profound for both disposal and handling of waste fluids. Without this exemption it is unclear 

whether either conventional or Marcellus production wastes could be disposed at POTW or 

landfills, and CWT facilities would not be allowed to treat the waste as it is currently being 

managed. 

Another result of this classification is that the majority of the solid waste material from 

drilling and production, as it is not considered hazardous material, can be disposed of onsite 

with appropriate permits (PA Ch. 25§ 78.62). Waste disposed of onsite must be solid material 

that has limited hazardous leaching properties (PA Ch. 25§ 78.62(b)). Only limited solid waste 

products are disposed of offsite from oil and gas drillers in Pennsylvania, less than 1 million tons 

a year of solid waste generally. 
 22

A Timeline of Waste Disposal from PA Wells 

Historically, the major disposal option used by oil and gas operators in Pennsylvania was 

treatment and disposal to surface waters. From 2001 to 2004, the majority of waste disposal 

was handled by CWT, with some reliance on a variety of other disposal options including 

POTWs, injection wells, and reuse. Effluent limits for oil and gas waste at POTW and CWT 

facilities followed state and federal guidelines, with mandatory requirements for total 

suspended solids (TSS), oil and grease, total iron, acidity, and pH (BOGM 2001; 40 CFR 435.32). 

 Waste volumes during this time were relatively small with approximately 144 Mgal ± 17.4 

produced each year. In 2004 and 2005 waste volumes began to increase with a dramatic jump in 

2008 to 428 Mgal, more than double the historic disposal volumes. The increase was driven by 

both record breaking natural gas prices and the increasing exploration of the Marcellus shale, 

using advanced drilling techniques, driving up both conventional and Marcellus waste volumes. 

The 2008 surge in waste alerted Pennsylvania to the first major regulatory issue in oil and gas 

waste disposal. 

Even meeting the state and federal discharge requirements, many POTWs and CWTs are not 

designed to remove common conventional pollutants found in produced water. The most 

important are the extremely high concentrations of TDS (See Section II). In 2010, the National 

Energy Technology Laboratory (NETL) conducted a survey of POTW and CWT facilities that 

accept Marcellus wastewater (Veil 2010). The survey contacted 18 out of the 32 POTWs shown 

to be accepting oil and gas wastewater5

 and found none of the 18 POTWs surveyed removed 

TDS during treatment (Veil 2010). Given the types of treatment that are required for the 

removal of TDS, it is assumed that none of the POTW plants have any TDS removal treatment. 

The survey also contacted many of the largest CWT facilities as well. For the ten largest CWT 

facilities, processing approximately 90% of wastewater sent to CWT, only 1 had installed a pretreatment plan that removed TDS and chlorides (Veil 2010b). 

 

5 The PA DEP database listed 32 POTW facilities accepting oil and gas wastewater. 
 23

Publically Owned Treatment Works (POTWs): 

Much of the increased waste volumes generated in 2008 were sent to POTW facilities (See 

Figure 14). In October of 2008 the PA DEP received reports of elevated TDS in the Monongahela 

River, impacting drinking water and industrial usage (Hopey 2008). The PA DEP stated that, 

“approximately 40 percent of the problem appears to be due to the high volumes of water from 

deep gas well drilling” (Hopey 2008). After the incident in the Monongahela, the PA DEP 

contacted POTWs along the Monongahela River, and potentially others in state, and limited 

their oil and gas wastewater acceptance volume (Kasey 2008). Several POTWs were limited to a 

maximum of 1% oil and natural gas wastewater disposal per day and many continue to operate 

with this as an official limit (Veil 2010b). 

Figure 14 - Volumes of wastewater disposed at POTW facilities over time. 

POWTs historically accepted approximately 6% of the waste being disposed of from oil and 

gas wells, with an average disposal from 2002 to 2006 of 7.0 Mgal ± 3.7. In 2008 POTW handled 

29% of the waste volume, increasing the treated waste volume to 120 Mgal. After 2008, the 

volume dropped to around to 12.7 Mgal in 2011, similar to the pre-surge volume of waste. The 

majority of waste treated by POTWs has historically been brine, with some fracking fluid and 

drilling fluid from Marcellus operators being accepted in 2008, 2009, and 2010. 
 24

Centralized Waste Treatment (CWTs): 

After 2008 the volume of waste continued to rise, but in 2009 much of the waste disposal 

shifted to CWT facilities, with an increase from around 150 Mgal in 2008 to 450 Mgal (See Figure 

15). Despite being commercial facilities, many CWTs did not treat TDS (Veil 2010b) and in 

August of 2009, the water quality in the Monongahela was impaired again (Sapien 2009). The PA 

DEP looked at the assimilative capacity of streams in Pennsylvania to dilute the highly saline 

wastewater and found many streams were almost at capacity for meeting water quality 

standards for TDS (Sapien 2009; Aunkst and Pine 2010). Pennsylvania decided to address the 

issue with regulations, limiting TDS discharge from new or existing facilities. The regulations 

were announced in April 2009, and took effect in August of 2010, effectively capping the 

amount of waste that could be accepted by POTW or CWT facilities (Rathburn 2009; PA DEP 

2011). The regulations limited waste disposal at CWT facilities in 2010 to around the 2009 levels, 

with an increase of only 34 Mgal, still five times higher than historic disposal levels from 2004 

(See Figure 15). 

Figure 15 – Volumes of wastewater disposed at CWT facilities though time. 

The Pennsylvania TDS regulations set limits on new or expanding discharges of wastewater, 

separating the waste into natural gas wastewater and all other industrial wastewater. Surface 
 25

discharges of waste from natural gas wells must have TDS less than 500mg/L, chloride less than

250 mg/L, and strontium and barium less than 10mg/L (PA 95.10). The new discharges must also 

comply with New Source Performance Standard under 40 CFR 437.45(b), the standards for CWT 

accepting several types of industrial waste. These standards cover a suite of metals, organics, 

and some conventional parameters (40 CFR 437.45(b)). 

The TDS regulations address only new and expanding loading of TDS. All previously 

permitted sources, called ‘grandfathered’ facilities, are allowed to continue discharging, until an 

expansion (>5,000 mg/L average per day increase) occurs (PA DEP 2011). Because the majority 

of CWT and POTW facilities did not have TDS criteria in their discharge permits, PA DEP used 

historic data to estimate the TDS loading from the facilities. 

The Wave of the Future 

As natural gas drilling expanded it became clear that surface water disposal was having a 

negative impact on water quality (Spear and Kenderes 2009). While the historic amount of oil 

and gas wastewater could be assimilated into streams without damage, the increased volumes 

of waste could no longer be diluted for disposal. State and federal regulatory agencies focused 

on reducing wastewater discharges to surface waters. 

In 2011 the EPA addressed pretreatment requirements for waste sent to POTWs, designed 

to prevent damage to the facility or the release of untreated pollutants. The EPA argues that oil 

and gas waste fails both the pass-through requirement, which bans the flow of pollution that 

passes through the waste treatment facility unchanged (40 CFR 403.3(p)), and interference, 

where waste either inhibits the treatment process or affects the disposal of sewage sludge (40 

CFR 403.3(k)). The first argument, that TDS is a pass-through pollutant, may have been negated 

by Pennsylvania’s authorizing TDS levels for POTW plants through the 2010 TDS regulations (40 

CFR 403.5(a)(2)(ii)). However, the argument that oil and gas wastewater may cause interference, 

harming the biological processes in POTW plants and reducing the effectiveness of biological 

treatments, is still valid (Hanlon 2011). Because the EPA regulates waste to POTWs at a national 

level, disposal at POTWs may be soon be barred in all states, a consideration for others in the 

northeastern region with limited waste disposal options (Hanlon 2011). 
 26

The PA DEP also identified additional contaminants of concern in oil and gas wastewater. In 

April 2011, the PA DEP requested that drilling operators voluntarily cease delivering wastewater 

to 15 ‘grandfathered’ POTW and CWT facilities (Perry 2011).6 A study of downstream impacts 

from a facility had shown elevated bromide levels in state waters (Perry 2011). Elevated 

bromide levels have been shown to increase cancer causing disinfection byproducts at water 

treatment facilities (Pressman et al. 2010; Perry 2011). 

Although some ‘grandfathered’ facilities are still discharging oil and gas wastewater to 

streams without treatment, the regulatory focus is driving a shift to other waste disposal 

options. Of the developing disposal options two were already in use, injection wells and reuse, 

and a third option, CWT or mobile treatment units that can reduce TDS, became available very 

recently. 

Underground Injection Wells 

Underground inject is the mostly commonly used disposal method for onshore oil and gas 

wastewater, but underground injection wells are limited in Pennsylvania, with only 6 operating 

wells (Clark and Veil 2004; Johnson 2011). Pennsylvania may have additional capacity for 

injection wells, but it uses many underground areas for natural gas storage, with the majority of 

potential injection well sites already in use for other purposes (GMSAC 2011). 

Ohio has significant number of injection wells and is the major acceptor waste for injection 

disposal. Based on the analysis of injection well disposal sites included in the database, Ohio 

accepts 92% of injected waste. West Virginia has identified only 2 commercial injection disposal 

wells (Manchin 2010) and has limited records for injection well disposal volumes, accepting only 

3% of injection well waste. 

Costs have been rising for waste injection in Ohio, with a regulation in 2010 that increased 

the disposal price from $0.05 per barrel to $0.20 per Bbl for out of ‘region’ waste (OLSO 2010). 

Additionally, a series of earthquakes were linked to an injection well in Youngstown, leading to 

stricter regulations and mounting public concern (OH DNR 2012). 

 

6 See Appendix A for the list of operators. 
 27

Figure 16 – Injection well disposal volumes of oil and gas wastewater through time. 

Despite increased cost and regulations, injection wells are the fastest growing disposal 

method behind reuse. The technologies needed to treat brine for disposal at a limit of 500 mg/L 

TDS are expensive and reuse poses its own challenges (See Reuse and Advanced CWT). In 2008 

approximately 0.3% of Marcellus waste was disposed of in injection wells, while in 2010 and 

2011 the amount was around 10% of total waste volumes. Injection wells are able to accept any 

of the waste types for disposal, with the vast majority of waste at injection wells being brine 

waste. This is expected because of the cost of disposal at injection wells does not depend on the 

waste quality. 

The ability for injection wells to accept waste both in Pennsylvania and surrounding states is 

constrained, with a limited number of injection-well formations available and growing concerns 

about the safety of these wells. Potential growth in oil and gas production in Ohio and West 

Virginia may lead to higher demand for injection wells in those states. With high transport costs 

to injection wells and potentially rising costs for disposal, injection wells may soon be pricier and 

less available for waste acceptance. 
 28

Reuse 

Recycling is one of the fast growing disposal methods, with considerable political weight 

encouraging recycling options for natural gas wastewater disposal (GMSAC 2011). In 

Pennsylvania, the new TDS rules have increased the push to recycle more wastewater. 

During reuse, the wastewater is commonly blended with fresh water for a future hydraulic 

fracturing job (Mantell 2010). Other reuse options that are not feasible in Pennsylvania due to 

waste quality are agricultural uses, where low-TDS brine wastes are reused for irrigation or 

livestock operations, or industrial reuses where lower quality water can be replace high quality 

water in certain processes (IOGCC 2006; Hum et al. 2005). While these options are possible, 

generally they require a very low level of TDS and other constituents, limiting the feasibility for 

the majority of Marcellus waste even outside of Pennsylvania (IOGCC 2006). 

Initial efforts to reuse wastewater in hydraulic fracturing faced difficulty creating a high 

quality fracturing fluid from re-used water (Bryant et al. 2010; Economides and Martin 2007; See 

Table 5). The high salt, chemicals and metals in wastewater limited the ability to reuse the water 

as the contaminants impacted the effectiveness of hydraulic fracturing chemicals (Bryant et al. 

2010). Pressure to reuse wastewater came from two directions. Areas like Pennsylvania, with 

limited disposal options, looked to recycling wastewater to reduce overall wastewater volumes 

and prevent the use of potentially contaminating disposal practices (GSMAC 2011). Area like 

Texas, with limited freshwater supplies, focused on recycling to reduce the need for freshwater 

sources to mix into the fracking fluids (Pierce et al. 2010). 

Table 5 – The maximum levels of constituents that could be present to reuse waste fluids 

for hydraulic fracturing mixtures in 2007. 

pH 6-8

Iron <10 ppm

Oxidizing Agents None

Reducing Agents None

Carbonates < 300 ppm

Bicarbonates < 300 ppm

Bacteria None

Cleanliness Reasonable

Econmides and Martin 2007

2007 Water Level Criteria for Hydraulic Fracturing 
 29

Over time new fracturing chemicals have been developed specifically to address the 

chemistry of recycled fluids, but there are still limitations on the constituents that may be 

present in mixing a high quality hydraulic fracturing fluid with recycled water. The most current 

list of limitations was taken from the New York SGEIS, shown in Table 6, which came out in 

September 2011 (NYSDEC 2011). 

Table 6 – The maximum levels of constituents that may be present to reuse waste fluids 

for hydraulic fracturing mixtures in 2011. 

Several parameters required for reuse, most notably TDS, have increased dramatically since 

reuse for hydraulic fracturing was initially considered. However, based on the range of 

contaminates shown in fracking and brine wastewater (See Table 2) much of the waste must be 

treated in some way prior to reuse. Conventional treatments are similar to treatment in many 

industries, filtration to remove suspended solids or coagulation to remove oil and grease, and 

are regularly conducted at the well site (Mantell 2010). Because of the changes in fracking 

chemical blends, many wastewaters can now be used in fracturing mixtures with only 

conventional filtration treatments (Mantell 2010). 

Advanced treatment options, to remove dissolved constituents, may also be used for reuse 

depending on the quality of the waste streams. Advanced treatment options are available in 

mobile units at well sites or in advanced CWT facilities (Horn 2009; Veil 2010b). The advantage 

of using advanced treatments for reuse is the quality needed is much lower than for surface 

disposal, especially in Pennsylvania, which can reduce the costs of advanced treatment options 

(Veil 2010b; See Advanced CWT). 

2011 Waste Level Criteria for Hydraulic Fracturing

Chlorides 3,000-90,000 mg/L

Calcium 350-1,000 mg/L

Suspended Solids <50 mg/L

Entrained oil and soluble organics <25 mg/L

Bacteria < 100 cells/100mL

Barium Low levels 

NYSDEC 2011
 30

Figure 17 – Volumes of wastewater reused from oil and natural gas though time. 

Reuse increased dramatically in 2010 and 2011, becoming the most commonly used method 

for disposing of waste in 2011 (See Figure 17). There are clear advantages to the reuse of 

wastewater, reducing the volumes of fresh water that must be used by drillers while also 

reducing the volumes of waste produced. However, in the very long term, reuse must be 

considered a complex form of storage. Reusing wastewater will alter wastewater volumes, but 

will still eventually require the disposal of waste fluids. Reuse also requires potentially long-term 

storage of fluid in pits or tanks on site. There are currently regulations limiting long-term storage 

of waste fluids in the majority of states containing the Marcellus formation (Wiseman 2010). 

These regulations range from 45 days (New York) to 9 months (Pennsylvania), but they may be 

adjusted to promote increased recycling (Wiseman 2010). When considering longer term 

storage in pits several problems are presented, including infiltration from rainwater, the offgassing of chemicals, and wildlife contact with wastewater pits (BOGM 2001; Colburn 2011; 

Ramirez 2009). Several oil and gas drillers store wastewater in tanks, which limits air/water 

contact, prevents contact with wildlife and blocks infiltration from rain flow (Mantell 2010; Atlas 

2011; Cabot 2011). 
 31

 When considering reuse as an option, well operators evaluate the economics of reuse: how 

much does water acquisition, transport, and disposal cost relative to any storage, treatment and 

transport that must occur for wastewater reuse (Mantell 2010). The quantity and timing of 

waterwater recovery from wells can strongly impact these costs, especially given that brine 

volumes must be collected over long periods (Mantell 2010). As shown in Figure 17, reuse of 

fracking and drilling fluid is relatively higher than reuse of brine due partly to waste quality and 

partly to the timing of waste generation (Mantell 2010). 

The limitations of reuse are found in the need for additional drilling, the quality of 

wastewater relative to hydraulic fracturing needs, and storage of materials. While reuse is an 

excellent option for reducing waste volumes, it requires a mixture of treatment, storage and 

continued fracturing to be a functional waste handling method. While the projections of growth 

are extremely large, it is unclear whether reuse will be a viable option for all operators in all 

locations. 

Advanced CWT 

During the later period of gas production, after 2009, a much wider range of CWT facilities 

were proposed or built with advanced waste treatment technologies to reduce TDS prior to 

reuse or disposal (Veil 2010b). Figure 18 shows the shift in CWT facilities from 2009 to 2011. In 

2009, 69% of waste was disposed in CWT facilities and of that 90% was discharged to surface 

waters without TDS treatment. By 2011, only 31% of waste was disposed in CWT facilities, with 

only 48% being discharged to surface waters without TDS treatment. The zero liquid discharge 

facilities, which are approximately 23% of CWT disposal in 2011, use conventional and advanced 

treatment options to generate only re-usable salts and distilled water products, and thus do not 

discharge fluids (Veil 2010b). The development of advanced CWT facilities to treat TDS protects 

surface waters, but can have high costs and high energy needs. The use of these facilities is 

much more expensive than POTW or historic CWT facilities (CSM 2009). 
 32

Figure 18 - The two pie charts show the overall disposal method for 2009 and 2011 

respectively, with side bars indicating the disposal method by CWT facility. (PA DEP 2012; Veil 

2010; Hapchuk 2012). 

There are a variety of different treatment technologies that are used by advanced CWT 

facilities, and of these have different energy, quality, and cost requirements. The most 

commonly discussed advanced treatment options are reverse osmosis, thermal distillation, 

electro-dialysis, and ion exchange (NYSDEC 2011). Of the available treatment options, only 

thermal distillation and reverse osmosis are being considered for use in the Marcellus shale (Veil 

2010b). Currently other advanced treatment options are only able to manage relatively low 

levels of TDS in influent, or have large energy costs relative to TDS levels (CSM 2009; See Table 

7). 
 33

Table 7 – Factors for various advanced treatment options to remove TDS. 

1

 URS 2011, 2 TRRC 2011, 3 Horn 2009, 4 NETL 2012, 5 CSM 2009, 6 Veil 2010b 

Most advanced treatment technologies require pre-treatment to remove oil and grease, 

TSS, and some dissolved constituents that may cause scaling. The most common type of pretreatment appears to be filtration (NYSDEC 2011). After filtration, the waste is may be treated 

with chemicals to precipitate dissolved contaminants that can form scale or salt precipitates 

during treatment (NYSDEC 2011). 

Thermal distillation makes no distinctions between waste quality, but requires a very high 

input of energy. Thermal distillation is already in use in the Barnett shale in Texas, treating 

waste in mobile units at well sites (TRRC 2011). Two facilities in the Marcellus are already using 

thermal distillation, and several other zero liquid discharge facilities in the Marcellus are using a 

combination of extensive pretreatment and thermal distillation (Veil 2010b). 

Reverse osmosis uses advanced membranes with pressure gradients to separate dissolved 

contaminants (URS 2011). Reverse osmosis is limited to TDS levels around 45,000 mg/L, 

although higher level TDS may be treated with a reduction in efficiency and increased 

membrane impacts (CSM 2009). Reverse osmosis has been used extensively in desalinating 

seawater and occasionally on produced water in other areas of the country, but is only under 

consideration for the Marcellus (CSM 2009; URS 2011). 

Treatment

Energy 

cost1

Energy Input 

Relative 

to TDS1

Applicable 

to1

Pretreatment 

Requirement1

Final 

Water 

TDS1In Use?

Ion Exchange Low

Low 

increase All Waste Filtration

200-500 

mg/L

Yes, Montana and 

Wyoming 4

Reverse 

Osmosis Moderate Increase

Moderate 

TDS Extensive

200-500 

mg/L

Yes, Texas and 

proposed 

Pennsylvania1,6

Eletrodialysis 

Reversal High

High 

Increase High TDS Filtration

200-1000 

mg/L

Thermal 

Distillation High Indepen. High TDS Minimal <10 mg/L

Yes, Texas and 

Pennsylvania 2,6

Ozone/ 

Ultrasonic/ 

Ultraviolet Low Increase All Water Filtration Variable Yes, Texas 3

a

 Feed TDS >20,000 mg/L
 34

Section II - Conclusion 

Figure 19 - Waste disposal trends overtime for conventional and Marcellus wastewater. 

Over time different disposal method have gained favor with well operators or disfavor with 

regulators. Disposal has shifted from historical disposal methods, mostly to surface waters, to 

dispose of fluids through reuse, injection wells and advanced CWT (See Figure 19). Surface 

disposal still occurs, especially for waste fluids from conventional natural gas wells. 

It is unclear whether the state regulatory system, or a federal regulatory system being 

considered by the EPA, would be the best solution for this problem. Considerations in this area 

include issues of waste quality, availability of disposal options, and costs/feasibility of treatment 

options. The current regulatory standards of 500 mg/L encourage drillers to dispose of waste 

through reuse or injection wells because the disposal standard requires intensive treatment. A 

better solution might be to set a higher TDS level for treatment plants and remove any 

authorization of historic waste disposal or differences between conventional and Marcellus 

waste. This would use the assimilative capacity of Pennsylvania streams to the highest extent 

without over or under treating waste from different waste streams. 
 35

Future Concerns - Landfill Disposal 

Landfills play an important role in waste disposal, as they are often the acceptors of 

byproduct waste from CWT and POTW facilities (Veil 2010, Alexander and Shilling 2011). There 

are growing concerns around landfills accepting waste sludge from treatment plant operators 

disposing of significant amounts oil and gas wastewater. One of the largest concerns for landfill 

acceptance of waste is the presence of elevated levels of NORM in waste material, especially 

sewage sludges (Urbina 2011; NYSDOH 2009). Pennsylvania already has a requirement for 

landfills to have a Radiation Protection Action Plan (PA § 270.140a). Under the radiation plans, 

waste disposed at landfills has been screened for radioactive material, but at present no waste 

has exhibited radioactive levels that would require further action by the landfill (Alexander and 

Shilling 2011). 

A second question is the disposal of saltcake, the waste sludge from CWT facilities with TDS 

treatment systems that handle large volumes of oil and gas waste. At present it is unclear 

whether landfill disposal of large volumes of salt-rich sewage sludge could have negative 

impacts. Studies of the impact of salt on landfill clay liners indicate that there are potential 

increases in hydraulic conductance or swelling of the liner (Arasan et al. 2010). No studies have 

been conducted directly on the impact of natural gas salts on landfill liners or the potential 

impacts of a shift to facilities producing large volumes of salt cake on landfills. 

Proposed State and Federal Regulatory Changes: 

At present the EPA has not promulgated any regulations for shale gas effluent (or other 

onshore oil and gas wastewater disposal), but the EPA has noted that it will develop effluent 

limits for both coal-bed methane and shale gas wastewater (EPA 2011). The new regulations are 

currently being scoped and it is unclear what pollutants would be included or what treatment 

would be required for disposal (B. Damico, personal communication, February 13, 2012). The 

effluent limits would be applied under the requirements for direct discharges and will probably 

include some level of TDS or chloride control, although the process is still in planning and list of 

considered pollutant is not available (B. Damico, personal communication, February 13, 2012). 

Although these regulations will be important, it must be noted that rise in gas prices in 2008 
 36

launched an increase in conventional oil and natural gas waste disposal. The conventional well 

waste would not be required to meet shale gas effluent requirements, limiting the surface water 

protection provided by these regulations. 

Pennsylvania’s Water Resource Advisory Committee is currently reviewing a draft proposing 

more stringent chloride, dissolved oxygen and sulfate requirements (WRAC 2012). These limits 

would create stringent standards for some of the disposal parameters commonly found in TDS 

and would probably be applied to plants grandfathered into the TDS regulations (WRAC 2012). 

Section III: Projections: 

Shale gas production has increased dramatically in recent years, with a 17% growth rate 

from 2000 to 2006 and a 48% growth rate from 2006 to 2010 (EIA 2012c; See Figure 20). This 

growth rate is only expected to increase in the future, with a range for shale gas production in 

2035 from 5.5-17.1 trillion cubic feet (EIA 2012c). The largest of the shale gas reserve available 

is the Marcellus (EIA 2008) and, although Pennsylvania was the first state to significantly 

develop this resource, surrounding states have the potential for major gas reserves as well 

(Soeder and Kappel 2011). 

Figure 20 – Estimates of natural gas resource extraction over the next 20 years (EIA 2012c). 
 37

Pennsylvania is expected to continue extensive production of natural gas from the 

Marcellus. The highest predictions show a continued strong growth, with estimates of 12.0 

billion cubic feet equivalents (bcfe) per day in 2015 and 17.5 bcfe/day in 2020, a growth of rate 

around 100% of production per year (Considine et al. 2011). Comparing the short-term 

estimates from the report to production, the report estimates 3.5 bcfe per day in 2011 while 

calculated Marcellus production was 2.88 bcfe per day in 20117 (Considine et al. 2011). 

West Virginia began shale gas exploration in the Marcellus in 2005, but lagged behind 

Pennsylvania in the authorizing of shale gas permits after 2008 (WV DEP 2012). At present West 

Virginia has 727 active Marcellus wells, but 2,072 permits for Marcellus wells have been 

approved and have permits increased by 25% from 2010 to 2011 (WV DEP 2012). 

Ohio also predicts growth, in both the Marcellus and the Utica shale, which lies below the 

Marcellus (Weinstein and Partridge 2011; See Figure 5). At present Ohio has 33 wells drilled, 

with 4 wells in active production in the Utica shale (Thomas et al. 2012). Estimates of future 

drilling ranges from 1,918 wells by 2014 (Thomas et al 2012) to 4,000 wells by 2015 (Kleinhenz 

2011) with some advocating for even lower estimates due the lower price for natural gas and 

potential impacts of industry funding on report results (Weinstein and Partridge 2011). 

At present New York State has banned high volume hydraulic fracturing, defined as greater 

than 80,000 gallons and is currently working on a final SGEIS for hydraulic fracturing and shale 

gas extraction (NYSDEC 2012). No predictions of shale gas exploration can be made until a clear 

regulatory picture emerges. 

The lowest projections see shale gas as an unsustainable bubble, with high over-head costs 

requiring a much higher wellhead price ($7.00/Mcf) for sustained growth (Burman 2010). Under 

these circumstances, limited growth for shale gas could be met by CWT facilities, but recycling 

might decrease due to limited availability of fracture jobs to reuse wastewater. Additionally, the 

cost of disposal at advanced CWT facilities may be especially burdensome, leading to waste 

being redirected of older ‘grandfathered’ facilities. 

 

7

 Calculates natural gas equivalent as 5.8 Mcf per barrel of oil or condensate produced. 
 38

The majority of predictions indicate continued growth in Marcellus drilling. Estimates range 

across the states ranges from around 4,000 wells in total to more than 15,000 wells in the three 

states allowing drilling. These increases would generate enormous volumes of waste. Given the 

current strains being seen in the disposal system, the growth of shale gas will require continued 

efforts to find safe disposal methods. 

Conclusions: 

The expansion of natural gas drilling into the Marcellus shale formation has vastly increased 

both gas and wastewater production in Pennsylvania. A comparison between Marcellus wells 

and conventional wells shows that natural gas production from the Marcellus shale is more 

efficient than from conventional formations, with approximately three times as much gas 

produced per gallon of wastewater. Despite the increased efficiency, Pennsylvania currently 

produces much higher volumes of wastewater because the production of natural gas has 

dramatically increased, mostly due to Marcellus shale wells. 

The increase in wastewater overwhelmed available disposal methods during the early 

period of drilling from 2004 to 2009, with consequences for surface water quality. Overtime 

regulations were put into place to address waste disposal, shifting treatment methods from 

surfaces discharges to reuse, injection wells, and advanced waste treatment. Each of these 

options will be needed to address future growth in natural gas extraction, but injection wells are 

very limited in the northeast and cannot absorb significantly more waste. Reuse has already 

proven very flexible at absorbing large quantities waste, with an enormous increase between 

2009 and 2011. However, reuse does not permanently dispose of waste and has limitations 

regarding the quality and timing of wastewater recovery. Advanced waste treatment options are 

gaining in popularity, but remain expensive and energy intensive. 

Given the anticipated future growth in shale gas production in the northeast, reuse and 

advanced treatment options must be promoted to protect surface water quality. Regulatory 

agencies need to consider how to encourage safe, viable alternatives to surface discharges by 

supporting reuse and advanced waste treatment to manage ever increasing wastewater 

volumes. 
 39

References: 

Alexander, J and L. Shilling. 2011. The Impacts of the Natural Gas Industry on Landfill Operations. Penn 

State Extension Webinar with Jay Alexander, General Manager of Wayne Township Landfill and Larry 

Shilling, Regional Vice President of Casella Waste Systems. Retrieved from 

http://extension.psu.edu/naturalgas/webinars/recorded/impacts-of-natural-gas-industry-on-landfilloperations. 

American Petroleum Institute (API). 2009. Hydraulic Fracturing Operations – Well Construction and 

Integrity Guidelines. October 2009. Retrieved from 

http://www.api.org/~/media/Files/Policy/Exploration/API_HF1.ashx

American Petroleum Institute (API). 2010. Water Management Associated with Hydraulic Fracturing. June 

2010. Retrieved from http://www.api.org/~/media/Files/Policy/Exploration/HF2_e1.ashx. 

American Petroleum Institute (API). 2011. Horizontal Shale Gas [Video]. Licensed from John Perez 

Graphics and Design. Retrieved from http://www.api.org/policy-and-issues/policyitems/hf/drilling_video.aspx

Arasan, S., Akbulut, R.K., Yetimoglu, T., and G. Yilmaz. 2010. Swelling Pressure of Compacted Clay Liners 

Contaminated with Inorganic Salt Solutions. Environmental and Engineering GeoScience. Vol. 16(4) 401-

409. 

Arthur, D., Bohm, B., and M. Layne. 2008. Hydraulic Fracturing Consideration for Natural Gas Wells of the 

Marcellus Shale. All Consulting. Retrieved from 

http://www.thefriendsvillegroup.com/HydraulicFracturingReport1.2008.pdf

Atlas Resources (Atlas). 2011. RE: EPA Request for Information on Marcellus Shale Flowback Water. 

Communication from Atlas Resources to Jaqueline Morrison, Land and Chemicals Division of EPA Region 

3. May 25, 2011. Retrieved from http://www.epa.gov/region3/marcellus_shale/pdf/responses2info-req5-

12-11/atlas1-208.pdf

Aunkst, D. and E. Pine. 2010, November 18. PA Dept of Environmental Protection’s Regulatory Update. 

Penn State Extension Webinar with Dana Aunkst and Eugene Pine from the Pennsylvania Department of 

Environmental Protection [Video]. Retrieved from 

http://extension.psu.edu/naturalgas/webinars/recorded/pa-dept-of-environmental-protectionsregulatory-update. 

Blauch, M.E., Myers, R.R., Moore, T.R., and B.A. Lipinski. 2009. Marcellus Shale Post-Frac Flowback 

Waters – Where is all the Salt Coming From and What are the Implications? Society of Petroleum 

Engineers. SPE 125740. 

Boyer, C., Kieschnick, J., Suarez-Rivera, R., Lewis, R. and G. Walters. 2006. Producing Gas from Its Source. 

Oilfield Review, Autumn 2006. Retrieved from 

http://www.slb.com/~/media/Files/resources/oilfield_review/ors06/aut06/producing_gas.ashx. 
 40

Burman, A. 2010. Shale Gas—Abundance or Mirage? Why The Marcellus Shale Will Disappoint 

Expectations. Energy Bulletin. Retrieved from http://www.firstenercastfinancial.com/pdfs/100101.pdf. 

Bureau of Oil and Gas Management (BOGM). 2001. Oil and Gas Wastewater Permitting Manual. 

Pennsylvania Department of Environmental Protection. (Doc. Num. 550-2100-002). 

Bureau of Waste Management (BWM). 2010. Residual Waste Codes (RWC). Pennsylvania Department of 

Environmental Protection. August 2010. Retrieved from 

http://www.elibrary.dep.state.pa.us/dsweb/Get/Document-80896/2540-PM-BWM0404.pdf. 

Bryant, J., Welton, T., and J. Haggstrom. 2010. Will flowback or produced water do? Exploration and 

Production. September 2010. Retrieved from 

http://www.halliburton.com/public/pe/contents/Papers_and_Articles/web/A_through_P/0910HEP_Sand

_HAL.PDF

Cabot Oil & Gas Corporation (Cabot). 2011. RE: EPA Request for Information on Marcellus Shale Flowback 

Water. Communication from Cabot Oil & Gas Corporation to Jaqueline Morrison, Land and Chemicals 

Division of EPA Region 3. May 25, 2011. Retrieved from 

http://www.epa.gov/region3/marcellus_shale/pdf/responses2info-req5-12-11/cabot.pdf

Caen, R., Darley, H.C.H., and G. R. Gray. 2011. Composition and Properties of Drilling and Completion 

Fluids 6 edition. Gulf Professional Publishing: Waltham, MA. 

Canadian Association of Petroleum Producers (CAPP). 2011. Upstream Dialogue: The Facts on Natural Gas.

September 2011. Retrieved from http://www.capp.ca/getdoc.aspx?DocId=196037&DT=NTV. 

Capacasa, J. 2011. Administrative Order for Compliance and Request for Information. Example Letter sent 

to 13 Facilities in Pennsylvania by the Water Protection Division of the EPA Region 3 Office. September 28, 

2011. Retrieved from http://www.epa.gov/region03/marcellus_shale/pdf/resource-extorders/alleghenyvalley.pdf. 

Casert, R. 2012. EU prepares for potential gas crisis. Associated Press. February 3, 2012. Accessed 

February 5, 2012. Retrieved from 

http://www.google.com/hostednews/ap/article/ALeqM5gxiKUuzNhdwlfof9zS4fZWJSVyNA?docId=6431e2

6b541d43de9fa5ee94c21925cd

Clark, C.E. and J.A. Veil. 2009. Produced Water Volumes and Management Practices in the United States. 

Argonne National Laboratory. U.S. Department of Energy, Oak Ridge, TN. Retrieved from 

http://www.evs.anl.gov/pub/doc/ANL_EVS__R09_produced_water_volume_report_2437.pdf 

Colborn T, Kwiatkowski C, Schultz K, Bachran M. (in press). Natural gas operations from a public health 

perspective. International Journal of Human & Ecological Risk Assessment. Retrieved 

from http://www.endocrinedisruption.com/files/NaturalGasManuscriptPDF09_13_10.pdf 

Colorado School of Mines (CSM). 2009. An Integrated Framework for Treatment Management of 

Produced Water: Technical assessment of produced water treatment technologies. Retrieved from 

http://www.rpsea.org/attachments/contentmanagers/3447/07122-

12_Technical_Assessment_of_Produced_Water_Technologies_First_Edition_P.pdf. 
 41

Considine, T.J., R.Watson and S. Blumsack. 2011. The Pennsylvania Marcellus Natural Gas Industry: Status, 

Economic Impacts and Future Potential. Pennsylvania State University. Retrieved from 

http://marcelluscoalition.org/wp-content/uploads/2011/07/Final-2011-PA-Marcellus-EconomicImpacts.pdf. 

Department of Agricultural Economics and Rural Sociology (DAERS). 2010. Marcellus Education Fact Sheet: 

Withdrawals for Development of Marcellus Shale Gas in Pennsylvania. Pennsylvania State University. 

Accessed: Nov 1, 2010. Retrieved from http://pubs.cas.psu.edu/FreePubs/pdfs/ua460.pdf. 

Economides, M.J. and T. Martin. 2007. Modern Fracturing: Enhancing Natural Gas Production. ET 

Publishing: Houston, TX. 

Energy In Depth. 2010. History of Hydraulic Fracturing. Online, accessed Nov 1, 2010, Retrieved from 

http://www.energyindepth.org/in-depth/frac-in-depth/history-of-hf/

Energy Information Administration (EIA). 1993. Drilling Sideways – A Review of Horizontal Well 

Technology and Its Domestic Application. Retrieved from 

http://www.eia.doe.gov/pub/oil_gas/natural_gas/analysis_publications/drilling_sideways_well_technolo

gy/pdf/tr0565.pdf 

Energy Information Administration (EIA). 2011. Annual Pennsylvania Field Production of Crude Oil. Online, 

updated July 28, 2011, accessed Jan 15, 2012. Retrieved from 

http://www.eia.gov/dnav/pet/hist/LeafHandler.ashx?n=PET&s=MCRFPPA1&f=A

Energy Information Administration (EIA). 2012a. U.S. Natural Gas Wellhead Prices. Online, updated 

January 1, 2012 Retrieved from http://205.254.135.7/dnav/ng/hist/n9190us3m.htm. 

Energy Information Administration. (EIA). 2012b. Annual Pennsylvania Natural Gas Gross Withdrawals. 

Online, updated January 30, 2012, accessed February 5, 2012. Retrieved from 

http://www.eia.gov/dnav/ng/hist/n9010pa2a.htm. 

Energy Information Administration. (EIA). 2012c. Annual Energy Outlook 2012 Early Release Overview. 

Released January 23, 2012. Retrieved from http://www.eia.gov/forecasts/aeo/er/early_introduction.cfm. 

Environmental Protection Agency (EPA). 1987. Report to Congress: Management of Wastes from 

Exploration, Development, and Production of Crude Oil, Natural Gas, and Geothermal Energy. EPA 530-

SW-88-003. Washington, D.C. 

Environmental Protection Agency (EPA). 2011. Technical Support Document for the 2010 Effluent 

Guidelines Program Plan. Retrieved from 

http://water.epa.gov/lawsregs/lawsguidance/cwa/304m/upload/tsd_effluent_program_10_2011.pdf 

Frac Focus. 2011. Well Data taken from wells fracturing in Bradford Country from 2010 to 2011. Accessed 

December 2011. Retrieved from http://www.hydraulicfracturingdisclosure.org/fracfocusfind/. 

Governor’s Marcellus Shale Advisory Commission (GMSAC). 2011. Governor’s Marcellus Shale Advisory 
 42

Commission Report. Released July 22, 2011. Retrieved from 

http://www.mde.state.md.us/programs/Land/mining/marcellus/Documents/MSAC_Final_Report.pdf. 

Hanlon, J. 2011. Natural gas drilling in the Marcellus Shale under the NPDES program. Attachment to 

memorandum from James Hanlon, Direct of EPA’s Office of Wastewater Management to EPA Regions. 

March 16, 2011. 

Hapchuk, Inc. 2012. LAD – Treatment Facility Plant. Summary of LAD treatment facility technology. Online, 

accessed February 20, 2012. Retrieved from http://www.hapchukinc.com/lad.php. 

Horn, A. 2009 . Breakthrough Mobile Water Treatment Converts 75% of Fracturing Flowback Fluid to 

Fresh Water and Lowers CO2. Society of Petroleum Engineers. SPE 121104-MS. 

Hopey, D. 2008. DEP Seeks Cause of River Pollution. Pittsburgh Post-Gazette. October 22, 2008. Retrieved 

from http://www.uppermon.org/news/Pgh-Alleg/PG-DEP_seeks-22Oct08.htm. 

Hum, F., Tsang, P., Kantzas, A. and T. Harding. 2005. Is it possible to treat produced water for recycle and 

beneficial reuse? Society of Petroleum Engineers. PS2005-316. 

Humphries, H. 2009. DEP detects total dissolved solids over standards in Monongahela River. 

Pennsylvania Department of Environmental news release. October 14, 2009. Retrieved from 

http://www.portal.state.pa.us/portal/server.pt/community/newsroom/14287?id=2390&typeid=1

Interstate Oil and Gas Compact Commission (IOGCC) and All Consulting. 2006. A Guide to Practical 

Management of Produced Water from Onshore Oil and Gas Operations in the United States. Prepared for 

U.S. Department of Energy and National Petroleum Technology Office. 

Johnson, K. 2011. Underground Injection Wells as an option for disposal of shale gas wastewater policies 

and practicality. Penn State Extension Webinar with Karen D. Johnson, Chief, Ground Water and 

Enforcement Branch, US EPA, Region 3, Philadelphia. Retrieved from 

https://meeting.psu.edu/p28484535/?launcher=false&fcsContent=true&pbMode=normal. 

Kasey, P. 2008. PA Sewage plants ordered to refuse gas well drilling water. The State Journal. November 

14, 2008. Retrieved from http://www.uppermon.org/news/charleston/SJ-PA_Drilling_water14Nov08.htm. 

King, G.E. 2010. Thirty Years of Gas Shale Fracturing: What Have We Learned? Society of Petroleum 

Engineers. SPE 133456. 

Kleinhenz and Associates (Kleinhenz). 2011. Ohio‘s Natural Gas and Crude Oil Exploration and Production 

Industry and the Emerging Utica Gas Formation. September 2011. Retrieved from 

http://www.oogeep.org/downloads/file/Economic%20Impact%20Study/Ohio%20Natural%20Gas%20and

%20Crude%20Oil%20Industry%20Economic%20Impact%20Study%20September%202011.pdf. 

Long, S. 2009. Wastewater Woes: Will DEP for Wastewater with high Total Dissolved Solids. The River 

Reporter Climate Challenge. Online, accessed January 15, 2011. Retrieved from 

http://www.riverreporter.com/issues/09-04-23/head1-wastewater.html. 
 43

Mabile, M., Richardson, D., Garner, S., Broussand, and R. Smith. 2011. Holistic Drilling Fluid and Waste 

Management in the Fayetteville Shale. Society of Petroleum Engineers. SPE 144036. 

Mall, A. and D. Donnelly, 2010. Petition for Rulemaking Pursuant to Section 6974(a) of the Resource 

Conservation and Recovery Act Concerning the Regulation of Wastes Associated with the Exploration, 

Development, or Production of Crude Oil or Natural Gas or Geothermal Energy. Petition to Lisa Jackson,

Administrator of the U.S. Department of Environmental Protection from the National Resource Defense 

Council. September 8, 2010. Retrieved from http://docs.nrdc.org/energy/files/ene_10091301a.pdf

Manchin, J. 2010. Industry Guidance Gas Well Drilling/Completion, Large Water Volume Fracture 

Treatments. West Virginia Department of Environment (WVDEP). Retrieved from 

http://www.dep.wv.gov/oil-and-gas/GI/Documents/Marcellus%20Guidance%201-8-10%20Final.pdf

Mantell, M.E. 2011. Produced Water Reuse and Recycling Challenges and Opportunities Across Major 

Shale Plays. Presented at EPA Hydraulic Fracturing Study Technical Workshop #4. March 29-30, 2011; 

Arlington, VA. Retrieved from http://www.epa.gov/hfstudy/09_Mantell_-_Reuse_508.pdf. 

Milici, R. and Swezey, C. (2006). Assessment of Appalachian basin oil and gas resources: Devonian shale - 

middle and upper Paleozoic total petroleum system. U.S. Geological Survey, Open-File Report, pp. 2006-

1237.

National Energy Technology Laboratory (NETL). 2012. Produced Water Management Fact Sheet – Ion 

Exchange. Accessed April 16, 2011. Retrieved from 

http://www.netl.doe.gov/technologies/pwmis/techdesc/ionex/index.html. 

Natural Gas Europe. 2011. Exxon to Proceed with Hydraulic Fracturing in Poland. September 28, 2011. 

Retrieved from http://www.naturalgaseurope.com/exxonmobil-poland-hydraulic-fracturing

New York State Department of Environmental Conservation (NYSDEC). 2011. Revised Draft Supplemental 

Generic Environmental Impact Statement on the Oil, Gas and Solution Mining Regulatory Program: Well 

Permit Issuance for Horizontal Drilling and High-Volume Hydraulic Fracturing to Develop the Marcellus 

Shale and Other Low-Permeability Gas Reservoirs. September 7, 2011. Retrieved from 

http://www.dec.ny.gov/data/dmn/rdsgeisfull0911.pdf

New York State Department of Environmental Conservation (NYSDEC). 2012. SGEIS on the Oil, Gas, and 

Solution Mining Regulatory Program. Accessed April 12, 2012. Retrieved from 

http://www.dec.ny.gov/energy/47554.html. 

New York State Department of Health (NYSDOH). 2009. Bureau of Environmental Radiation Protection 

Comments “Supplemental Generic environmental Impact Statement on the Oil and Gas regulatory 

Program Well permit issuance for Horizontal Drilling and High-Volume Hydraulic Fracturing to Develop the 

Marcellus Shale and other Low-Permeability Gas Reservoirs. July 21, 2009. Retrieved from 

http://s3.amazonaws.com/propublica/assets/natural_gas/nysdoh_marcellus_concerns_090721.pdf

Niquette, M. 2012. Ohio Tries to Escape Fate as a Dumping Ground for Fracking Fluid. Bloomberg. 

February 1, 2012. Retrieved from http://www.bloomberg.com/news/2012-02-01/ohio-tries-to-escapefate-as-a-dumping-ground-for-fracking-fluid.html
 44

Obama, B. 2012. Transcript: Obama’s 2012 State of the Union. FoxNews. January 24, 2012. Retrieved from 

http://www.foxnews.com/politics/2012/01/24/transcript-obamas-2012-state-union/. 

Ohio Department of Environmental Protection (OH EPA). 2012. Shale Oil and Gas Drilling – Glossary of 

Terms. Accessed March 3, 2012. Retrieved from http://www.epa.ohio.gov/shale.aspx. 

Ohio Department of Natural Resources (OH DNR). 2012. Preliminary report on the Northstar 1 Class II 

Injection Well and the seismic events in the Youngstown, Ohio area. 

Ohio Legislative Service Commission (OLSC). 2010. Final Analysis: Senate Bill 165. Effective June 30, 2010. 

Retrieved from http://www.lsc.state.oh.us/analyses128/10-sb165-128.pdf. 

Paktinat, J. and B. O’Neil. 2011. High Brine Tolerant Polymer Improves the Performance of Slickwater Frac 

in Shale Reservoirs. Society of Petroleum Engineers. SPE 144210. 

Pennsylvania Code. Chapter 95 Wastewater Treatment Requirements. Section 10 Treatment 

requirements for new and expanding mass loadings of Total Dissolved Solids (TDS). Retrieved from 

http://www.pacode.com/secure/data/025/chapter95/chap95toc.html. 

Pennsylvania Department of Environmental Protection (PA DEP). 2011. Policy and Procedure for NPDES 

Permitting of Discharges of Total Dissolved Solids (TDS) – 25 Code 2011) Doc. Num. 385-2100-002. 

Retrieved from http://www.elibrary.dep.state.pa.us/dsweb/Get/Document-85967/385-2100-

002%20tech%20guidance.pdf

Pennsylvania Department of Environmental Protection (PA DEP). 2012. Records from Oil and Gas 

Management database. Accessed February 12, 2012. Retrieved from 

https://www.paoilandgasreporting.state.pa.us/publicreports/. 

Perry. S. 2011. Letter From Scott Perry to SM Energy Co. and other gas companies regarding elevated 

bromide levels. July 11, 2011. Retrieved from http://www.epa.gov/region3/marcellus_shale/pdf/letterpadep-to-epa7-26-11.pdf. 

Pierce, D., Bertrand, K. and C.C. Vasiliu. 2010. Water Recycling Helps with Sustainability. Society of 

Petroleum Engineers. SPE 134137 

Pilgram, S. 2011. French lawmakers ban controversial shale gas drilling. France24, November 11, 2011. 

Retrieved from http://www.france24.com/en/20110511-france-votes-ban-shale-gas-drilling-frackingump-sarkozy; 

Pressman, J.G. et al. 2010. Concentration, Chlorination, and Chemical Analysis of Drinking Water for 

Disinfection Byproduct Mixtures Health Effects Research: U.S. EPA’s Four Lab Study. Environmental 

Science and Technology. 44: 7184-7192. 

Rathbun, T. 2009 DEP Sets New Standards for Wastewater with high Total Dissolved Solids. Memo 

released April 16, 2009. Retrieved from 

http://www.portal.state.pa.us/portal/server.pt/community/newsroom/14287?id=2178&typeid=1. 
 45

Ramirez, P. 2009. Reserve Pit Management: Risks to Migratory Birds. U.S. Fish and Wildlife Region 6. 

Retrieved from http://www.fws.gov/mountain-prairie/contaminants/documents/ReservePits.pdf

Sapien, J. 2009. With Natural Gas Drilling Boom Pennsylvania Faces an Onslaught of Wastewater. 

Propublica. October 3, 2009. Retrieved from http://www.propublica.org/article/wastewater-from-gasdrilling-boom-may-threaten-monongahela-river. 

Shapiro, S., Dinske, C. and C. Langenbruch. 2010. Seismogenic index and magnitude probability of 

earthquakes induced during reservoir fluid stimulation. Society of Exploration Geophysicists. Vol 29(3) 

304-309. 

Soeder, D. and W. Kappel. 2009. Water Resources and Natural Gas Production from the Marcellus Shale. 

USGS Fact Sheet. Retrieved from http://pubs.usgs.gov/fs/2009/3032/pdf/FS2009-3032.pdf

Spear, R. and G. Kenderes. 2009. Cause and Effect Survey South Fork Tenmile Creek. Pennsylvania 

Department of Environmental Protection. February 2, 2009. Retrieved from 

http://files.dep.state.pa.us/Water/Wastewater%20Management/WastewaterPortalFiles/MarcellusShale

WastewaterPartnership/south_fork_tenmile_feb_2009.pdf

Texas Railroad Commission (TRRC). 2011. Water Use in the Barnett Shale. Updated January 24, 2011, 

accessed April 16, 2012. Retrieved from 

http://www.rrc.state.tx.us/barnettshale/wateruse_barnettshale.php. 

Thomas, A.R., Lendel, I., Hill, E.W., Southgate, D. and R. Chase. 2012. An Analysis of The Economic 

Potential for Shale Formations in Ohio. Funded by Ohio Shale Coalition. Retrieved from 

http://media.cleveland.com/business_impact/other/Shale%20Final%20Report.pdf. 

Urbina, I. 2011. Regulation Lax as Gas Wells’ Tainted Water Hits Rivers. New York Times February 26, 

2011. Retrieved from http://www.nytimes.com/2011/02/27/us/27gas.html?pagewanted=all#. 

URS Corporation (URS). 2011. Water-Related Issues Associated with Gas Production in the Marcellus 

Shale. Prepared for NYSERDA, Albany, NY. March 25, 2011. 

U.S. Department of Energy (US DOE). National Energy Technology Laboratory (DOE). 2009. Modern Shale 

Gas Development in the United States: A Primer. National Energy Technology Laboratory. Retrieved from 

http://www.netl.doe.gov/technologies/oil-gas/publications/EPreports/Shale_Gas_Primer_2009.pdf 

Veil, J.A., M.G. Puder, D. Elcock, and R.J. Redweik, Jr. 2004. A white paper describing produced water from 

production of crude oil, natural gas, and coal bed methane. DOE W-31-109-Eng-38. 

Veil, J.A. and C.E. Clark. 2010a. Produced Water volumes estimates and management practices. Society of 

Petroleum Engineers. SPE 125999-MS. 

Veil, J.A., 2010b, Water Management Technologies Used by Marcellus Shale Gas Producers. Argonne 

National Laboratory, Office of Fossil Energy, National Energy Technology Laboratory, July 2010. Retrieved 

from http://www.evs.anl.gov/pub/doc/Water%20Mgmt%20in%20Marcellus-final-jul10.pdf. 
 46

Volz, C., Ferrar, K., Michanowicz, D., Christen, C., Kearney, S., Kelso, M. and S. Malone. 2011. Contaminant 

Characterization of effluent from Pennsylvania Brine Treatment Inc., Josephine Facility being released into 

Blacklick Creek, Indiana County, Pennsylvania: Implications for disposal of oil and gas flowback fluids from 

brine treatment plants. Center for Health Environments, Department of Environmental and Occupational 

Health, University of Pittsburgh. March 25, 2011. Retrieved from

http://ia700608.us.archive.org/6/items/ContaminantCharacterizationOfEffluentFromPennsylvaniaBrineTr

eatment/Josephine_V2_CHEC_2011.pdf

Vukmanovic, O. 2011. UK firm says shale fracking caused earthquakes. Reuters. November 2, 2011. 

Retrieved from http://uk.reuters.com/article/2011/11/02/greenbiz-us-gas-frackingidUKTRE7A160020111102

Water Resource Advisory Council (WRAC). 2012. January 11, 2012 - Meeting Agenda. Harrisburg, PA. 

Retrieved from

http://files.dep.state.pa.us/PublicParticipation/Advisory%20Committees/AdvCommPortalFiles/WRAC/Ag

enda/1-11-12%20Agenda.pdf. 

Weinstein, A. and M.D. Partridge. 2011. The Economic Value of Shale Natural Gas in Ohio. Ohio State 

University. December 2011. Retrieved from http://aede.osu.edu/sites/drupalaede.web/files/Economic%20Value%20of%20Shale%20Dec%202011.pdf. 

West Virginia Department of Environmental Protection (WV DEP). 2012. Oil and Gas Database, records 

from the “Marcellus” formation. Accessed March 18, 2012. Retrieved from

https://apps.dep.wv.gov/oog/wellsearch_new.cfm

Wiseman, H. (2009) Untested Waters: The Rise of Hydraulic Fracturing in Oil and Gas Production and the

Need to Revisit Regulation. Fordham Environmental Law Review 115. 

Ziemkiewicz, P. 2008. High TDS in the Monongahela River: Analysis of the Chemical Data. Water Research

Institute. Accessed February 8, 2012. Retrieved from http://www.uppermon.org/Marcellus_Shale/MonOct-Dec-2008.htm 

Zoback, M., Kitasei, S., and B. Copithorne. “Addressing the Environmental Risks from Shale Gas 

Development,” World Watch Institute, July 2010. Retrieved from http://blogs.worldwatch.org/revolt/wpcontent/uploads/2010/07/Environmental-Risks-Paper-July-2010-FOR-PRINT.pdf