### MEMORANDUM

TO: Lisa Biddle, EPA

Karen Milam, EPA

FROM: Sarah Yates, ERG

Brent Ruminski, ERG

DATE: June 7 , 201 6

SUBJECT: Unconventional Oil and Gas (UOG) Drilling Wastewater Memorandum

(DCN SGE 01181 )

T his memorandum describes the data and methods that ERG used to compile oil and gas drilling wastewater volume s and characterization d ata for the Technical Development Document for Effluent Limitations Guidelines and Standards for Oil and Gas Extraction (TDD) ( DCN

SGE 01188 ). In addition to explanations of data compilation and analys e s, this memorandum provides discussions about types of oil and gas drilling fluids

, unconventional oil and gas ( UOG ) drilling wastewater volumes (per well)

, UOG drilling wastewater characteristics, and UOG drilling wastewater management practices

. The focus of this memorandum is on drilling wastewater generated by UOG wells. Table 1 lists the tables and figures in this memorandum along with the corresponding TDD table or figure number and underlying supporting memo from which the figure/table was generated. For those figures/tables ERG generated specifically for this memorandum, th e underlying data and analysis are contained in the Microsoft Excel A ttachment 1 (DCN SGE 01181 .A 0 1)

. Tables and figures that are pre sented in the TDD not listed in Table 1

e ither did not require calculations and/or analyses by ERG or are described in separate, supporting memoranda. The Crosswalk Memorandum between Proposed and Final Technical Development Document for Effluent Limitations Guidelines and Standards for Oil and Gas Extraction: Tables and Figures (DCN SGE01334) contains a crosswalk of all ta bles and figures in the TDD. Appendix F of the TDD contains the name of the relevant supporting memorandum for each TDD table and figure , where applic able. This memorandum is organized into the following sections:

 Section 1.0 overview of oil and gas drilling fluids

 Section 2.0 volumes and characteristics of UOG drilling wastewater

 Section 3.0 management of UOG drilling wastewater

 S ection 4.0 methodology used to generate Table 3 (TDD Table C

- 5) and Table 4 (TDD Tables C

- 10, C

- 12, C

- 14, C

- 16, and C

- 18) in this memorandum

 Section 5.0 describes ERG’s quality assurance procedures

 Section 6.0 lists the references used for these analyses

 Section 7.0 provides the attachment to this memorandum

For those figures/tables ERG generated specifically for this memorandum, the underlying data and analysis are contained in:Memorandum

June 7 , 2016 Page 2

 Attachment 1

– UOG Drilling Wastewater Volume and Characterization Data

Excel File (DCN SGE01181. A01).

For the tables/figures explained in more detail in this memorandum

, Table 1 provides the

TDD chapter , memorandum section, and attachment information.

Table 1 . List of Tables and Figures Discussed in this Memorandum

TDD Table or Figure

Number Memo Table or Figure Number and Title Memo.
Section Underlying

Supporting

Attachment

Figure C

- 1 Figure 2

. UOG Extraction Wastewater Volumes

Breakdown by Drill Type for UOG Wells in Pennsylvania (2004

– 201 4 ) 2.1 SGE 01182 .A 0 3 a

Table C

- 4 Table 2

. Average Drilling Wastewater Volumes for

Horizontal and Vertical Oil and Gas Wells in Pennsylvania 2.1 SGE 01182 .A 0 3 a

Table C

- 5 Table 3

. UOG Drilling Wastewater Volumes Generated

pe r Well by Formation 2.1 SGE 01181 .A 0 1 b

Table C

- 10, C

- 12, C

- 14,

C

- 16, and C

- 18 Table 4

. Concentrations of Constituents in UOG Drilling

Wastewater from Marcellus Shale Wells 2.2 SGE 01181 .A 0 1 b

Figure D

- 2 Figure 3

. UOG Drilling Wastewater Management and

Disposal Methods 3.0

-- a

Figure D

- 3 Figure 4

. Management of UOG Drilling Wastewater

Generated by UOG Wells in Pennsylvania (2008

– 201 4 ) 3.0 SGE 01182 .A 0 3 c

a

— This figure was generated by ERG for the purpose of this memorandum and the TDD but does not appear in any

attachment.

b

— These figures/tables were g enerated in this memorandum. The underlying data and analyses are contained in Attachment 1 (DCN SGE 01181 .A 0 1).

c

— These figures/tables were generated in another supporting memorandum (DCN SGE 01182 )

.

For definitions of common terms used throughout the TDD, the supporting memoranda, and memoranda attachments, please refer to the Glos sary in the introduction of the TDD.

1.0 O VERVIEW OF O IL AND G AS D RILLING F LUIDS

Drilling fluid is the circulating fluid used during the rotary drilling of oil and gas wells to clean and condition the hole and to counterbalance formation pressure. During drilling, well
operators circulate drilling fluids down the wellbore to cool the drill bit and to remove fragments of rock (i.e., drill cuttings) 1 from the wellbor e. O ther purposes of drilling fluids include: reduc ing friction between the drilling s tring and the sides of the hole, prevent ing inflow of fluids from the formation into the hole, cool ing the rotor and drill bit, transmit ting sensor readings from navigational tools, and providing stability to the borehole while drilling ( DCN SGE00090, DCN

SGE00 635 ; DCN SGE01009 ).

Figure 1 provides an overview of how oil and gas operators use drilling fluid. During the drilling process, drilling fluid (i.e., mud) is in jected down the well bore where it collects the drill

1 The particles generated by drilling into subsurface geologic formations and carried out from the wellbore with the drilling fluid.Memorandum

June 7 , 2016 Page 3

cuttings. The drilling fluids are circulated back up the well bore to the surface where the cuttings

are removed using shakers, desilters and centrifuges . The drilling fluid is then reinjected down

the wellbore. T he drilling fluids may be continuously recycled until the end of the drilling

process with this closed

- loop process while cuttings are managed and/or disposed of when they

are removed at the surface ( DCN SGE00090; DCN SGE00 635 ; DCN SGE01009 ).

Source: DCN SGE00801

Figure 1 . Drilling Fluid Circulation

1.1 Types of Drilling Fluids

There are four general types of drilling fluids:

 Compressed gases ;

 Water

- based drilling fluid ;

 Oil

- based drilling fluid ; and

 Synthetic oil

- based dri lling fluid

.Memorandum

June 7 , 2016 Page 4

Operators may use a combination of these drilling fluids while d rilling a single well. The drilling fluid used typically depends on the properties of the formation, well depth, associated regulations, and cost considerations ( DCN SGE01009 ) . W hile drilling, operators must ensure that the weight of the drilling fluid on the bottom of the well bore exceeds the pressure within the

formation. Pressures increase as well depth increases along with the likelihoo d of encountering gas pockets . At shallow depths during well drilling , where pressure and temperature are typically low, drillers use compressed gases because they are the least expensive

. As the well is drilled deeper

, pressures and temperatures increase

, requiring heavier drilling fluids (e.g., fresh water,

water

- based, or oil

- based fluids ) (DCN SGE00 635 )

.

The following list provides an overview of a typical drilling process in terms of the well depth versus the type of drilling fluid that operators might use

.

1. Shallow D epths: (e.g., 0

– 1,000 feet) Pressurized air is often used to drill vertically through the drinking water aquifer ( DCN SGE00 635 ; DCN SGE00345;

DCN SGE00280; DCN SGE00774 ; DCN SGE00090

, DCN SGE01009 )

.

2. Shallow to Medium Dep ths: (e.g., 1,000

– 3,500 feet) As the vertical sec tion of the well is drilled deeper, operators switch over to water

- based drilling fluids

. The purpose of the drilling fluid (e.g., cooling, stability) becomes more critical to account for increased pressure, temperature , and potential for pressurized gas pockets at these depths ( DCN SGE00 635 ).

3. Medium to Deep De pths: (e.g., 3,500 feet and deeper) At some depth, operators may switch to oil

- or synthetic

- based fluids as the vertical section of the well is drilled deeper a nd pressure , temperature , and potential for pressurized gas pockets continue to increase ( DCN SGE00 635 ). However, synthetic

- based fluids are not always used depending on the final depth and/or operator preference.

4. Formation D epth s ( i.e., Horizontal Leg ) : For horizontal ly

- or directional ly

drilled UOG wells, operators will continue to use the same drilling fluid they used at “medium to deep” depths for the directional or horizontal leg

. Operators may

use water

- , oil

- , or synthetic oil

- based drilling flu id s for this portion of the well drilling (DCN SGE00 635 )

.

Operators add chemicals to water

- and oil

- based drilling fluids to give the fluid its desired characteristics for drilling deeper, where pressure and temperature are higher relative to shallow depths. The following subsections describe the primary types of drilling fluids in more

detail

, including specific additives that may be used

.

1.1.1 Compressed Gases

Compressed or pressurized air is often used as drilling fluid fo r shallow wells, for drilling through the drinking water aquifer, or for rapid drilling through stable, hard rock formation s (DCN SGE00 635 )

. D ry air, nitrogen gas, mist, foam and aerated fluids are included in this
category (DCN SGE01009)

. The relatively l ow pressure of the gases (compared to water

- based drilling fluids) minimizes losses of drilling fluid into the ground and generates a rapid rate of penetration.Memorandum

June 7 , 2016 Page 5

1.1.2 Water

- based Drilling Fluid

Water

- based drilling fluids are more stable than compressed gases an d are used at

medium depths. However, they are also more expensive to use than compressed gases. Water

based fluids include water or a water miscible fluid as the suspending medium for solids. Water

based fluids may contain the following additives (DCN SGE 00 635 ; DCN SGE01009 ):

 Gels to enhance cutting

- carrying properties ;

 Lime to control pH ;

 Polymers to prevent exces sive seepage into the formation;

 Salt s to increase density and conductivity to allow the operator to analyze downhole

conditions via electric currents ; and/or

 Barite (barium sulfate), as needed, to add weight to the fluid

.

1.1.3 Oil

- based Drilling Fluid

Oil

- based drilling fluids use oil as their continuous phase with water as the dispers ed phase. The oil is often diesel or mineral oil

. Oil

- based fluids are more effective than water

- based

fluids at performing the primary functions of drilling fluids ; however, they are also more expensive. Oil

- based fluids better prot ect the formation from swelling, provide better weight

control , and degrade less rapidly than water

- based fluid. Oil

- based fluids may contain the following additives (DCN SGE 00 635 ; DCN SGE01009 ):

 Emulsifiers to keep water and fluid together ;

 Gels to enhance cutting

- carrying prop erties ; and/or

 Barite, as needed, to add weight to the fluid

.

1.1.4 Synthetic oil

- based Drilling Fluid

Operators may also use synthetic oil

- based drilling fluids which are technically equivalent to oil

- based drilling fluids described in Section 1.1.3 in that they are designed f or dri lling at deep depths (e.g., horizontal laterals of wells ) (DCN SGE01009). However, instead of using diesel oil and/or minera l oils, synthetic oil

- based drilling fluids use organic fluids (e.g., esters, polyeolefins, acetal, ether, and linear alkyl benzenes) that exhibit similar fluid properties

as diesel and mineral oils. Synthetic oil

- based drilling fluids have been referred t o as more environmentally friendly than oil

- based drilling fluids but are also more expensive ( DCN SGE01009)

. Synthetic oil

- based drilling fluids have lower toxicities, lower concentrations of certain priority pollutants 2 , lower bioaccumulation potential, and faster biodegradation rates than

oil

- based drilling fluid ( DCN SGE01006; DCN SGE01009 ). T he organic additives used in synthetic oil

- based drilling fluids are less toxic than the diesel and/or mineral oils used in oil

based drilling fluids (DCN SGE01009). Synthetic oil

- based drilling fluids also result in a smaller

volume of drilling wastewater to manage or dispose

.

2 These i nclude polynuclear aromatic hydrocarbons (PAHs) that are priority pollutants in Appendix A to 40 CFR
part 423. Thes e pollutants are constituents in oil

- based drilling fluids but not in synthetic oil

- based drilling fluids.Memorandum

June 7 , 2016 Page 6

2.0 V OLUMES AND C HARACTERISTICS OF UOG D RILLING W ASTEWATER

Drilling wastewater is the liquid waste stream separated from recovered drilling fluid 3 (mud) and drill cuttings during the drilling process

. As explained in Section 1.0 , operators are able to circulate the same drilling fluid down the w ellbore multiple times while drilling a single well. This is accomplished by removing the solids (i.e., drill cuttings) 4 from the drilling fluid on the well pad . However, at some point the drilling fluid is no longer usable and must be managed or disposed of by the operator

.

This section summarizes UOG drilling wastewater volume and characterization data from

available literature. Section 4.0 includes descriptions of the analyses that ERG performed to generate the data presented.

2.1 Volumes of UOG Drilling Wastewater

On a per well basis, UOG drilling wastewater accounts for a small portion of the total

UOG extraction wastewater compared to produced water. Figure 2 shows a breakdown of UOG extraction wastewater volumes generated from Marcellus shale wells in Pennsylvania based on data from Pennsylvania D epartment of Environmental Protection’s (PA DEP) statewide waste reports (DCN SGE0 1245 ) for all wells active between 2004 and 201 4

. An explanation of how ERG generated Figure 2 is described in a separate ERG memorandum: Analysis of PA DEP Waste Reports (DCN SGE 01182 ). 5 On average

, drilling wastewater contributes seven percent or less of total UOG extraction wastewater on a per well basis for UOG wells in Pennsylvania

. In Figure 2 , produced water is shown as its two primary components: flowback 6 and long

- term produced water 7

. The ratio of drilling wa stewater to flowback and long

- term produced water varies by formation and sometimes within the formation (DCN SGE 01188 ).

3 As described in Section 1.0 , drilling fluid is the circul ating fluid used in the rotary drilling of wells to clean and condition the hole and to counterbalance formation pressure.

4 The particles generated by drilling into subsurface geologic formations and carried out from the wellbore with the drilling fluid.

5 ERG analyzed the quantity and type of wastewater (e.g., drilling wastewater, long

- term produced water) as reported by operators in the PA DEP waste reports (DCN SGE01182).

6 Flowback is the produced water generated in the initial period after hydraulic f racturing (i.e., fracturing fluid, injection water, any chemicals added downhole, and varying amounts of formation water).

7 Long

- term produced water is the produced water generated during the production phase of the well after the initial flowback process . Long

- term produced water includes increasing percentages of formation water that make up the total volume of long

- term produced water.Memorandum

June 7 , 2016 Page 7

Source: DCN SGE 01182 ; DCN SGE 01182 .A 0 3

Figure 2 . UOG Extraction Wastewater Volumes Breakdown by Drill Type for UOG Wells

in Pennsylvania (2004

– 201 4 ) (TDD Figure C

- 1)

N early all of the drilling fluid used during drilling is recovered during the drilling process

as drilling wastewater (DCN SGE 00625). 8 The volume of drilling fluid require d in the drilling

process varies with the length of the wellbore

. The longer the wellbore, the more drilling fluid is required. For example, UOG wells that are drilled horizontally typically generate higher volumes of drilling wastewater than UOG wells tha t are drilled vertically

. Table 2

, based on PA DEP’s waste reports from 2004 to 201 4 (DCN SGE 01182 ) , supports these generalizations

.

Table 2

. Average Drilling Wastewater Volumes for Horizontal and Vertical Oil and Gas Wells in Pennsylvania (TDD Table C

- 4)

Resource Type Drill Type Average Drilling Fluid Volume per Well (gallons) Range of Drilling

Fluid Volume per Well (gallons) a Typical Total

Measured Depth b (feet) Number of Data

Points

UOG (shale) Horizontal 9 0 ,000 3, 4 00

– 200 ,000 7

, 300

– 13 ,000 3,961

UOG (shale) Vertical 8 3 ,000 5,000

– 190 ,000 6,000

– 7,000 230

Source: DCN SGE 01182

. A 0 3

a

— These ranges are based on the 10 th and 90 th percentile of volumes reported for individual wells.

b

— T otal measured depth is the true length of wellbore drilled (i.e., sum of the vertical and horizontal).

8 Some of the drilling fluid volume may be lost in the cuttings, to evaporation, and/or to seepage into the formation

b ut one operator reported these losses to be minimal.Memorandum

June 7 , 2016 Page 8

Table 3 shows volumes of drilling wastewater generated per well by UOG formation sorted from highest volume to lowest

. Existing l iterature often reports total drilling fluid volume used per well rath er than the drilling wastewater volume generated per well. As previously explained , operators confirmed that nearly all of the drilling fluid is recovered during the drilling
process as wastewater (DCN SGE 00625). Therefore, Table 3 presents all volumes as drilling wastewater volumes regardless of whether it was reported as drilling wastewater or drilling fluid

in the literature

. M ost data sources reported volumes without an indication of the well trajectory (i.e., hori zontal, vertical, directional). As explained above, drilling fluid/wastewater volumes generally increase with the total measured depth. Therefore

, Table 3 also presents the typical total measured depths for each formation that are reported in literature

.

Table 3

. UOG Drilling Wastewater Volumes Generated pe r Well by Formation (TDD

Table C

- 5)

Resource Type Formation Drilling Wastewater Volume (Gallons) Typical Total

Measured Well Depth b (feet) Number of

Data Points Range (Min

– Max) Median

Shale Haynesville &

Bossier 420,000

-

1,100,000 600,000 1 3 ,000

– 1 9 ,000 5

Tight Anadarko Basin 200,000

- 420,000 310,000

-- c 2

Shale Niobrara

-- a 300,000 7

, 5 00

– 1 3 ,000 1

Shale Barnett 170,000

- 500,000 250,000 8

, 5 00

– 1 4 ,000 6

Shale Permian 84,000

- 420,000 210,000

-- c 8

Tight Cleveland

-- a 200,000

-- c 1

Tight Granite Wash

-- a 200,000

-- c 1

Shale Eagle Ford 130,000

- 420,000 160,000 6 ,000

– 1 6 ,000 7

Shale Utica

-- a 100,000 6 ,000

– 1 9 ,000 1

Tight Mississippi Lime

-- a 100,000

-- c 1

Shale Marcellus 3,400

– 200,000 d 50 ,000 7

, 300

– 13 ,000 3,96 2

Source: See Attachment 1 (DCN SGE 01181 .A 0 1)

.

a

— ERG identified only one data point for these formations. Therefore, there is no range to display.

b

— Total measured depth is the true length of wellbore drilled (i.e., sum of the vertical and horizontal).

c

— Information is unknown.

d

— ERG used maximum and minimum volume data for all formations except for the Marcellus formation because of the limited number of data points that were identified in existing literature. Due to the large number of volume data points for the Marcellus formation, ERG calculated the 10th and 90th percentile values to display as the range as opposed to presenting maximum and minimum values

.

2.2 C haracteristics of UOG Drilling Wastewater

S everal categories of constituents are present in most types of oil and gas drilling

waste water (DCN SGE 00733):

Salt ( typically measured as total dissolved s olids or electrical conductivity); Oil and grease ; I norganic and organic compounds; and

C hemical additives used during drilling

.Memorandum

June 7 , 2016 Page 9

ERG has identified less i nformation in the public literature on UOG drilling wastewater

characteristics , as compared to information that has been found on UOG produced water

characteristics

. All of the data ERG located on UOG drilling wastewater was specific to the

Marcellus Sha le. Table 4 present s typical concentrations of select constituents that are frequently reported in UOG drilling wastewater from Marcellus shale wells

. Where multiple d ata points (i.e., samples) were available, Table 4 show s the range and median concentrations associated with each parameter and the associated number of data points. Constituents are grouped and sorted by pollutant categories. Table 4 contains all of the drilling wastewater characterization data provided in Table C

- 10, Table C

- 12, Table C

- 14, Table C

- 16, and Table C

- 18 of the TDD

.

As shown in Table 4

, TSS concentrations can vary significantly in drilling wastewater

. This is likely dependent on how efficiently the drill cuttings are removed by the operator during

the drilling process (see Figure 1 in Section 1.0 )

. Operators measured TSS c oncentrations as high

as 6 0 percent by mass in drilling was tewater

.Memorandum

June 7 , 2016 Page 10

Table 4

. Concentrations of Constituents in UOG Drilling Wastewater from Marcellus

Shale Wells

Constituent Category Parameter Units Range Median/Average a Number

of Samples Number

of

Detects

Classical and

Conventional Alkalinity (as

CaCO) mg/L 110

- 42,000 1,600 11 11

Ammonia mg/L 0.98

- 35 7 8 8

BOD 5 mg/L 80

- 1,100 390 8 8

Chloride mg/L 160

- 23,000 12,000 12 12

COD mg/L 150

- 9,300 1,800 8 8

Hardness mg/L 1,400

- 46,000 4,400 12 12

Oil and Grease mg/L ND

- 150 2.5 8 4

pH S.U. 6.8

- 12 9 12 12

Phosphate mg/L 16

- 16 16 4 4

Specific

Conductance uS/cm 1,100

- 60,000 19,000 10 10

TDS mg/L 560

- 80,000 31,000 14 14

TSS mg/L 120

- 600,000 28,000 16 16

Ions Contributing

to TDS Bromide mg/L 23

- 210 110 5 5

Sulfate mg/L ND

- 1,600 220 13 10

Organic s Benzene μg/L ND

- 40 ND 20 5

Ethylbenzene μg/L

-- b 9.6 4 4

Ethylene glycol mg/L

-- 500 1 1

Toluene mg/L ND

- 0.01 ND 8 1

Xylene (m,p) μg/L ND

- 80 ND 20 8

Xylene (o) μg/L

-- b 88 4 4

Metals Aluminum mg/L 1.7

- 6,900 38 12 12

Arsenic mg/L ND

- 4.2 ND 12 6

Barium mg/L 2.6

- 2,000 13 14 14

Beryllium mg/L ND

- 0.018 ND 8 2

Boron mg/L ND

- 2.7 0.17 8 4

Cadmium mg/L ND

- 0.005 ND 8 1

Calcium mg/L 150

- 15,000 1, 3 00 13 13

Chromium mg/L ND

- 11 0.01 12 8

Cobalt mg/L ND

- 1.8 ND 8 3

Copper mg/L ND

- 17 0.83 8 6

Iron mg/L 4.2

- 18,000 86 12 12

Lead mg/L ND

- 8 0.35 12 10

Lithium mg/L ND

- 1.2 ND 8 1

Magnesium mg/L ND

- 3,600 290 12 11Memorandum

June 7 , 2016 Page 11

Table 4

. Concentrations of Constituents in UOG Drilling Wastewater from Marcellus

Shale Wells

Constituent Category Parameter Units Range Median/Average a Number

of Samples Number

of

Detects

Manganese mg/L ND

- 350 4.3 12 11

Mercury mg/L ND

- 0.029 ND 8 2

Molybdenum mg/L

-- 0.1 1 1

Nickel mg/L ND

- 16 0.55 12 9

Potassium mg/L

-- b 8,800 4 4

Selenium mg/L ND

- 0.11 ND 8 3

Silver mg/L ND

- 0.01 ND 8 1

Sodium mg/L 170

- 16,000 2,900 12 12

Strontium mg/L 1.8

- 1,500 21 13 13

Zinc mg/L ND

- 38 2.1 12 10

Radioactive

Measurements Gross alpha pCi /L 17

- 3,000 130 5 5

Gross beta pCi/L 32

- 4,200 1,200 5 5

Source: See Attachment 1 (DCN SGE 01181 .A 0 1)

. ND

– non detect (n ot all sources report detection limit s ).

a

— Median value in the “Reported Measured/Average Value” column in the “UOG DF WW Chara. Data” tab

b

— Source only reported median value based on multiple samples

.

3.0 M ANAGEMENT OF UOG D RILLING W ASTEWATER

As detailed in Section D.2 of the TDD , historically, the oil and gas industry has most commonly managed UOG extraction wastewater , which includes drilling wastewater, by underground injection (DCN SGE 01188 ). T he UOG industry is increasingly turning to reuse/recycle

, and, in some geographic areas

, transfer to centralized waste treatment (CWT) facilities to manage growing volumes of UOG extra ction wastewater. The National Petroleum Council (NPC) describes oil and gas drilling wastewater management in three tiers (DCN

SGE 00733 ):

Tier 1: Waste Minimization

– The generation of waste is minimized by using closed loop circulation systems during dri lling , which reduces the total amount of waste that must be managed and/or disposed of in addition to minimizing costs.

Tier 2: Reuse/Recycle

– Operators can reuse/recycle drilling wastewater in subsequent drilling and/or fracturing jobs 9

.

Tier 3: Disposal

– When drilling wastewater cannot be managed via reuse/recycle,
operators must use other manage ment options, including dispos al

.

9 One operator reported that treated drilling wastewater using induced gas flotation (IGF) may be used for hydraulic

fracturin g base fluid (DCN SGE00625)Memorandum

June 7 , 2016 Page 12

Common methods for managing and /or disposing of drilling wastewater are listed below

and shown in Figure 3 ( DCN SGE00081 ).

 Transfer to a CWT facility 10 ;

 Dispos al via injection into Class II disposal well s 11 ;

 On

- site burial

– temporary fluid storage i n on

- site open earthen or lined pits with

burial of residual solids after fluids are solidified, removed from the top, or evaporated ;

 Disposal via l andfill

– fluids are solidified and then contained in constructed or

natural excavations within the landfil l ; and

 Land application (not shown in Figure 3 )

– spreading over land surface where natural bioremediation is enhanced by tilling and nutrient applications

.

Figure 3

. UOG Drilling Wastewater Management and Disposal Methods (TDD Figure D

- 2)

C urrently, the most detailed publicly available source of information on drilling
wastewater management and disposal practices is sp ecific to oil and gas extraction in Pennsylvania

. PA DEP periodicall y releases a database that captures the management of drilling

10 CWT facilities that accept UOG extraction wastewater are described in a separate ERG memorandum titled Analysis of Centralized Waste Treatment (CWT) Facilities Accepting UOG Extraction Wastewater (DCN

SGE0 1178 ).

11 Underground injection wells are described in a separate ERG memorandum titled Analysis of Active Underground Injection for Disposal Wells (DCN SGE0 1187 ).Memorandum

June 7 , 2016 Page 13

wastewater generated by all oil and gas wells (DCN SGE 01182 ) and Figure 4 shows a timeline of drilling wastewater management practices used by UOG operators in Pennsylvania for 200 8 through 201 4

. As can be seen in the figure, UOG drilling fluid volumes generated in creased substantially in 2009 due to development of the Marcellus shale. UOG operators utilized POTWs

from 2008 through 201 1 to manage drilling wastewater (indicated by red in the figure). However, the use of POTWs for the management of UOG drilling wastew ater (and produced water) stopped after 2011 with t he use of reuse/recycle increas ing starting in 2011

.

Note: As reported in the PA DEP Waste Reports, “Other” may include storage pending disposal or reuse and other (reported as “other”).

Source: DCN SGE 01182 ; DCN SGE 01182 .A 0 3

Figure 4

. Management of UOG Drilling Wastewater Generated by UOG Wells in

Pennsylvania (2008

– 201 4 ) (TDD Figure D

- 3)

4.0 M ETHODOLOGY FOR TDD F IGURES /T ABLES G ENERATED IN THIS M EMORANDUM

The fol lowing two subsections describe the methodology that ERG used to generate

Table 3 (TDD Table C

- 5) and Table 4 (TDD Tables C

- 10, C

- 12, C

- 14, C

- 16, and C

- 18) in thisMemorandum

June 7 , 2016 Page 14

memorandum. As previously explained, all other figures and tables (e.g., Figure 4 ) in this memorandum are described in other supporting memoranda

.

4.1 Table 3

– Drilling Wastewater Volumes Generated by UOG Wells by Formation

TDD Table C

- 5 “ UOG Drilling Wastewater Volumes Generated pe r Well by Formation ” ( i.e., Table 3 in Section 2.1 of this memorandum ) shows volumes of UOG drilling

fluid/wastewater generated per well for various formations . The raw data and analysis are

com piled in the “UOG DF WW Volume Data” and “UOG DF WW Volume Summary” tabs in Attachment 1 (DCN SGE 01181 .A 0 1 ) . The following two subsections explain how ERG generated this table

.

4.1.1 UOG Drilling Wastewater Volume Data Entry

ERG entered raw UOG drilling wastewat er volume data reported in literature into the

“UOG DF WW Volume Data” tab in A ttachment 1 (DCN SGE 01181 .A 0 1). Where available,

d ata fields entered included: 12

 Resource type ( i.e., s hale, tight )

 Formation

 Well trajectory ( i.e., horizontal, not reported )

 Volume (gallons)

– This is the reported volume of drilling fluid used or drilling wastewater generated per well in gallons. Some references report volumes used for drilling UOG wells as opposed to wastewater generated. ERG presented the results as drilling wastewater volumes. 13

 Number of data points

– This is the number of wells the volume data is based on , if reported. If not reported, ERG assigned this value as 1. In some cases, this is equivalent to the number of wells the reported data is based on. Howe ver, as explained above, not all references reported the number of wells

.

 Reference ( i.e., DCN number )

4.1.2 UOG Drilling Wastewater Volume Summary Calculations

After entering all data in the “UOG DF WW Volume Data” tab in Attachment 1 (DCN

SGE 01181 .A 0 1) , ERG c alculated the summary statistics that appear in the TDD Table C

- 5 ( i.e.,

Table 3 in Section 2.1 of this memorandum) in the “UOG DF WW Volume Summary” tab. ERG

calc ulated the following for each formation reported in the “UOG DF WW Volume Data” tab:

 Minimum value

– Smallest value in the “ Volume (gallons)” column in the “UOG DF

WW Volume Data ” tab.

12 ERG marked data elements that were not included in the literature as “not reported” in Attachment 1.

13 Based on communication with industry, ERG assumed that the volume of drilling fluid used is equal to the volume of drilling wastewater generated on a per well basis (DCN SGE 00625 ). ERG did not distinguish between reported volume of drilling fluid used and drilling wastewater generated in this analysis.Memorandum

June 7 , 2016 Page 15

 Maximum value

– Largest value in the “Volume (gallons)” column in the “ UOG DF

WW Volume Data ” tab.

 Range

– Combines the minimum and maximum values into a range.

 Median value

– Median value in the “Volume (gallons)” column in the “UOG DF

WW Volume Data ” tab.

 Number of data points

– Sum of the “N umber of Data Points” column in the data i n the “UOG DF WW Volume Data ” tab.

4.2 Table s 4 and 5

– Characteristics of Select Pollutants in UOG Drilling Wastewater

TDD Table s C

- 10, C

- 12, C

- 14, C

- 16, and C

- 18 (i.e., Table 4 in Section 2.2 of this

memorandum ) show concentrations of pollutants found in UOG drilling wastewater

. The raw data and analysis are compiled in the “UOG DF WW Chara

. Data” and “UOG DF WW Chara

. Summary” tabs in Attachment 1 (DCN SGE 01181 .A 0 1) . The following two subsections explain how ERG generated these tables

.

4.2.1 UOG Drilling Waste water Characteristics Data Entry and Standardization

ERG entered raw characterization data reported in literature into the “UOG DF WW
Chara. Data” tab in A ttachment 1 (DCN SGE 01181 .A 0 1). Data fields entered included: 14

 Formation;

 Cat egory [ of pollutant ] (e.g. , classical, metal) ;

 Measured parameter;

 Reported measured/average value ( i.e., value reported in literature);

 Uncertainty (applies to radioactive constituents);

 Number of samples;

 Units;

 Reference ( i.e., DCN number ) ; and

 Notes.

Because naming conventions , terminology, and measured units differed by data source

, ERG standardized each data field to allow for comparison and summary of data across the entire

data set . The following list provide s detail s on how ERG standardized data from literature in the

“UOG DF WW Chara. Data” tab

.

 Parameter Standardization and Pollutant Category Assignments

- ERG created a list of all parameters included in the various sources and consolidated parameter names to

account for different spellings or abbreviations. For example, “Co” and “Cobalt”
were standardized to “Cobalt.” Pollutant c ategories for each standard parameter name were also assigned to allow sorting of measured parameters. For example, aluminum

was assigned to the “Metals” category.

 Reported Measured/Average Value s

- In some cases, data sources indicated that minimum, median, and/or maximum values did not exceed the limit of detection. To standardize the data for aggregation, ERG assigned all reported non detect s as zero

14 ERG marked data elements that were not included in the literature as “not reported” in Attachment 1.Memorandum

June 7 , 2016 Page 16

values. After analyzing the data, any zero m inimum , median , or maximum values

were converted back to non detect in the TDD and memorandum tables

.

 Wastewater Description

– ERG only used literature that specifically reported the wastewater type associated with the characterization data as drilling was tewater. However, different sources may use different terms for drilling wastewater. ERG captured wastewater desc ribed as: “pit water”, “drilling”, and “mud”.

 Unit s of Measure Standardization

– ERG converted reported pollutant concentrations

to standardized units of measure appropriate for each parameter. For example, total suspended solids were sometimes reported as a percent . ERG converted these values to mg/ L by multiplying the percent by 1,000,000 (e.g., 38% would be converted by multiplying 0.38 by 1,000,000 to get the value of 380,000 mg/L )

.

4.2.2 UOG Drilling Wastewater Characteristics Summary Calculations

After consolidat ing and standardizing all data in the “UOG DF WW Chara. Data” tab,

ERG calculated summary statistics that appear in the “UO G DF WW Chara. Summary” tab in Attachment 1 (DCN SGE 01181 .A 0 1). ERG calculated the following for each parameter r eported

in the “UOG DF WW Chara. Data” tab :

 Min imum value

– Smallest value in the “ Reported Measured/Average Value ” column

in the “UOG DF WW Chara. Data” tab.

 Max imum value

– Largest value in the “ Reported Measured/Average Value ” column

in the “UOG DF WW Chara. Data” tab

.

 Range

– Combines the minimum and maximum values into a range.

 Median value

– Median value in the “ Reported Measured/Average Value ” column in

the “UOG DF WW Chara. Data” tab

. 15

 Number of data points

– Sum of the number of data points represented by the data in

the “UOG DF WW Chara. Data” tab

.

 Number of detects

– Sum of the n umber of data points that were not non

- detects or

zeros represented by the data in the “UOG DF WW Chara. Data” tab

.

5.0 Q UALITY C ONTROL P ROCEDURES

All of the analyses presented in this memorandum adhered to the Environmental Engineering Support for Clean Water Regulations Programmatic Quality Assurance Project

Plan (PQAPP) (DCN SGE00957) and the Unconventional Oil and Gas (UOG) Supplemental Quality Assurance Project Plan (SQAPP) (DCN SGE00 958 ), including collecting, evaluating, and analyzing existing data and information about drilling fluids and drilling wastewater

.

Specifically, ERG used the procedures described in Section 4 of the PQAPP to gather and manage existing data in support of the UOG rulemaking. ERG staff entered reference

information for relevant sources into the UOG Literature Review database. The ERG i ndex keeper reviewed all reference information, assigned each reference a Document Control Number

15 One source (SGE00774) provided the average measured result for four samples but did not provide the individual sample results. ERG did not w eight these values during the calculation of the median value.Memorandum

June 7 , 2016 Page 17

(DCN ), imported the reference information into the UOG Project File Index database, and saved referenced files in the Electronic Project File folder.

ERG also used the procedures described in Section 3 of the SQAPP when collecting existing data for use in the UOG rulemaking. ERG used a combination of sources, including reports, papers, and online databases from state regulatory agencies such as departments of

e nvironmental protection and oil and gas commissions. As shown in Table 5 in this memorandum, ERG assigned a source flag (A, B, C or D) to all referen ces used in these analyses. ERG defines each source flag as follows:

 Source Flag A

- J ournal articles and documents prepared by or for a government agency (e.g., site visit reports, industry meeting notes);

 Source Flag B

- Documents prepared by a verifie d source 16 that include citation information (e.g., operator reports, vendor documents, university publications);

 Source Flag C

- Documents prepared by a verified source that do not include citation information (e.g., operator reports, vendor documents, co nference presentations); and

 Source Flag D

- Documents prepared by a source that could not be verified and that

do not include citation information

.

EPA and ERG followed the procedures described in Section 7.0 of the PQAPP to generate, evaluate, and analy ze data using a spreadsheet. ERG conducted the following QA checks during the analyses:

 ERG performed a 20 percent check of all data entry.

 ERG performed a 100 percent check of all analyses and calculations, and documented

these in the internal version of the spreadsheet.

 ERG had a senior staff member familiar with ELGs and the UOG rulemaking review

the results from each analysis.

6.0 R EFERENCES

Table 5 provides DCNs and citations for references used in these analyses and their assigned source flag. Definitions for source flags are located in Section 3.0 of the SQAPP (DCN SGE00958) and also in Section 5.0 of this memorandum

.

16 ERG considered sources as “verified” if we were able to find information about the author outside of the reference document. ERG primarily verified information by looking for company/organiza tion websites that confirmed the author’s affiliation with the UOG industryMemorandum

June 7 , 2016 Page 18

Table 5 . References

DCN Reference Citation Source Flag a

SGE00010 Ground Water Protection Council. 2009. Modern Shale Development in the

United States: A Primer. A

SGE00081 API. 2009. Environmental Protection for Onshore Oil and Gas Production

Operations and Leases. B

SGE00090 NYSDEC. 2011. Suppl. Generic Env. Imp. Statement on Oil, Gas, & Soln. Mining

Reg. Prgm. Prelim. Rev. Draft. A

SGE00276 U.S. EPA. 2012. Meeting with XTO Energy, Inc. about Unconventional Oil and

Gas Sanitized. A

SGE00280 U.S. EPA. 2013. Site Visit Report: Anadarko Petroleum Corporation Marcellus

Shale Gas Operations. (January 9). A

SGE00298.A18 Don Warlick. 2012. Water Management for Shale Plays An Overview of the

Niobrara Shale. Warlick Energy. C

SGE00345 Lewis, Aurana. 2012. Wastewater Generation and Disposal from Natural Gas

Wells in Pennsylvania. Duke University

. B

SGE00368.A01 U.S. EPA. 2013. Key Documents About Mid

- Atlantic Oil and Gas Extraction.

(January 9) A

SGE00428 ERG. 2013. Notes on Penn State Webinar: The Utica Reservoir. B

SGE00625 U.S. EPA. 2015. Site Visit Report: Southwestern Energy Fayetteville Shale Gas

Operations. Sanitized. A

SGE00635 U.S. EPA. 2012. Site Visit Report Chesapeake Energy Corporation Marcellus

Shale Gas Operations Sanitized. A

SGE00639 Nicot et al. 2012. Oil & Gas Water Use in Texas: Update to the 2011 Mining

Water Use Report. Univ of TX at Austin. (September) A

SGE00641 Nicot, Jean

- Philippe. 2013. Geographical, Geological, and Hydrogeological

Attributes of Formations in the Footprint of the Eagle Ford Shale. A

SGE00691 U.S. EPA. 2013. Summary of the Technical Workshop on Water Acquisition

Modeling: Assessing Impacts Through Modeling and Other Means. (September). A

SGE00732 Huffmyer, Russell and Gehucheten, John. 2013. Recovering Valuable Byproducts

from Oil and Gas Wastes. HDR Engineering, Inc. IWC

- 13

- 37. (November 17). B

SGE00733 National Petroleum Council (NPC). 2011. Waste Management Paper #2

- 24.

Technology Subgroup of the Operations & Environment Task Group. (September 15). B

SGE00774 Ziemkiewicz, P. 2013. Water Quality Literature Review and Field Monitoring of

Active Shale Gas Wells. (February 15). A

SGE00801 Argonne National Laboratory (ANL). 2011. Drilling Waste Management

Information System A

SGE00957 ERG. 2013. Environmental Engineering Support for Clean Water Regulations

Programmatic Quality Assurance Project Plan (PQAPP). A

SGE00958 ERG. 2014. Unconventional Oil and Gas (UOG) Supplemental Quality Assurance

Project Plan (SQAPP). A

SGE00986 Rost, J. 2010. Municipal Authority of the City of McKeesport: Analysis of Gas

Well Wastewaters as Required Under the PADEP Admin Order Dated 10/23/08. A

SGE00987 Rost, J. 2010. Municipal Authority of the City of McKeesport Analysis of Gas

Well Wastewaters as Required Under the PA DEP AO Dated October 23, 2008. AMemorandum

June 7 , 2016 Page 19

Table 5 . References

DCN Reference Citation Source Flag a

SGE01006 U.S. EPA. 2000. D e v e l o p ment Doc ument Final Effl ue nt L i m i tat io ns G ui d e l i n e s &

St a nd a rds Synthetic

- Based Dri l l i ng Fluids & Oth e r Non

- Aqueous Dril li ng Fluids

in O&G Extr action P oi nt Source C a t e g o ry. A

SGE01009 Caen, R., Darley, et al. 2011. Composition and Properties of Drilling and

Completion Fluids. 6th edition. Gulf Professional Publishing: Waltham, MA. B

SGE01028 PA DEP. 2015. Technologically Enhanced Naturally Occurring Radioactive

Materials (TENORM) Study Report. A

SGE01178 ERG. 2016. Analysis of Centralized Waste Treatment Fa cilities (CWTs)

Accepting UOG Extraction Wastewater. A

SGE01182 ERG. 2016. Analysis of Pennsylvania Department of Environmental Protection’s

Oil and Gas Waste Reports. A

SGE01182.A03 ERG. 2016. Analysis of Pennsylvania Department of Environmental Protection’s

Oil and Gas Waste Reports

- Attachment 3

- Data Calculations. A

SGE01187 ERG. 2016. Analysis of Active Underground Injection for Disposal Wells. A

SGE01188 U.S. EPA. 2016. Technical Development Document for Effluent Limitations

Guidelines and Standards for Oil and Gas Extraction. A

SGE01245 ERG. 2015. Pennsylvania Department of Environmental Protection’s (PA DEP)

Statewide Oil and Gas Waste Reports. (November) A

SGE01334 ERG. 2016. Memorandum Providing a Crosswalk between Tables and Figures in

the Proposed and Final Technical Development Document for Effluent

Limitations Guidelines and Standards for Oil and Gas Extraction

. A

a

— ERG defines each source flag as follows:

 Source Flag A

- J ournal articles and documents prepared by or for a government agency (e.g., site visit reports, industry meeting notes);

 Source Flag B

- Documents prepared by a verified source that include citation information (e.g., operator reports, vendor documents, university publications);

 Source Flag C

- Documents prepared by a verified source that do not include citation information (e.g., operator reports, vendor documents, conference presentations); and

 Sou rce Flag D

- Documents prepared by a source that could not be verified and that do not include citation

information.

7.0 A TTACHMENTA TTACHMENT 1: UOG D RILLING W ASTEWATER V OLUME AND C HARACTERI ZATION
D ATA E XCEL F ILE (DCN SGE 01181 .A 0 1)