1

RPSEA 

Evaluation of the Aqua Pure Mechanical 

Vapor Recompression System in the 

Treatment of Shale Gas Flowback Water

Report No. 08122-05.11

Barnett and Appalachian Shale 

Water Management and Reuse 

Technologies

Contract 08122-05 

March 12, 2012

Principal Investigator Principal Investigator

Tom Hayes, Ph.D.

Coordinator, Environmental 

Engineering Solutions

Gas Technology Institute

1700 S. Mount Prospect Rd. 

Des Plaines, IL

Blaine F. Severin, Ph.D., P.E.

Senior Process Engineer

Environmental Process Dynamics, Inc.

4117 Spinnaker Ln.

Okemos, MI
LEGAL NOTICE

This report was prepared by the Gas Technology Institute as an account of work sponsored 

by the Research Partnership to Secure Energy for America, RPSEA. Neither RPSEA members 

of RPSEA, the National Energy Technology Laboratory, the U.S. Department of Energy, nor 

any person acting on behalf of any of the entities:

a. MAKES ANY WARRANTY OR REPRESENTATION, EXPRESS OR IMPLIED WITH 

RESPECT TO ACCURACY, COMPLETENESS, OR USEFULNESS OF THE INFORMATION 

CONTAINED IN THIS DOCUMENT, OR THAT THE USE OF ANY INFORMATION, 

APPARATUS, METHOD, OR PROCESS DISCLOSED IN THIS DOCUMENT MAY NOT 

INFRINGE PRIVATELY OWNED RIGHTS, OR

b. ASSUMES ANY LIABILITY WITH RESPECT TO THE USE OF, OR FOR ANY AND ALL 

DAMAGES RESULTING FROM THE USE OF, ANY INFORMATION, APPARATUS, 

METHOD, OR PROCESS DISCLOSED IN THIS DOCUMENT. 

THIS IS AN INTERIM REPORT. THEREFORE, ANY DATA, CALCULATIONS, OR CONCLUSIONS 

REPORTED HEREIN SHOULD BE TREATED AS PRELIMINARY. 

REFERENCE TO TRADE NAMES OR SPECIFIC COMMERCIAL PRODUCTS, COMMODITIES, OR 

SERVICES IN THIS REPORT DOES NOT REPRESENT OR CONSTIITUTE AND ENDORSEMENT, 

RECOMMENDATION, OR FAVORING BY RPSEA OR ITS CONTRACTORS OF THE SPECIFIC 

COMMERCIAL PRODUCT, COMMODITY, OR SERVICE. 
THIS PAGE INTENTIONALLY LEFT BLANK 
1

Contents

Contents............................................................................................................................................... 1

List of Figures...................................................................................................................................... 2

List of Tables....................................................................................................................................... 2

List of Photographs.............................................................................................................................. 3

Acronym and Abbreviations................................................................................................................ 3

1 Abstract........................................................................................................................................ 4

2 Introduction ................................................................................................................................. 5

3 Background.................................................................................................................................. 8

4 Maggie Spain Facility.................................................................................................................. 9

4.1 Preconditioning..................................................................................................................... 9

4.2 Mechanical Vapor Recompression ..................................................................................... 13

4.3 MVR Process Evaluation Results....................................................................................... 16

4.4 Energy Utilization............................................................................................................... 19

4.5 Fate of Various Chemical Constituents.............................................................................. 20

5 Discussion.................................................................................................................................. 24

5.1 Economics........................................................................................................................... 25

6 Summary.................................................................................................................................... 26

References ......................................................................................................................................... 27

Acknowledgements ........................................................................................................................... 27

Appendix ........................................................................................................................................... 28
2

List of Figures

Figure 1: MVR Process Flow Sheet, Maggie Spain Facility 11

Figure 2: Simplified Flow Diagram for the Aqua Pure Mechanical Vapor 

Recompression Process

14

Figure 3: Example of Daily Performance of a Single Nomad (No.3) MVR 17

Figure 4: Water Distribution between Distillate and Concentrate During 60 Day 

Sample Period

18

Figure 5: Distribution of Dissolved Salts between the Distillate and the 

Condensate Streams During 60 Day Sample Period

19

Figure 6: Standard Cubic Feet of Natural Gas Required to Treat Influent to 

Distillate (Composite Data Three MVR Units)

20

Figure 7: Fate of Total Dissolved Solids in the Maggie Spain Facility 21

Figure 8: Fate of Calcium, Magnesium, and Strontium in the Maggie Spain 

Facility

21

Figure 9: Fate of Barium, Boron, and Iron in the Maggie Spain Facility 22

Figure 10: Fate of Suspended Solids in the Maggie Spain Facility 23

Figure 11: Fate of Total Petroleum Hydrocarbons in the Maggie Spain Facility 23

Figure 12: Fate of Total BETEX in Maggie Spain Facility 24

List of Tables

Table 1: Influent and Post Clarifier Water Analysis 10

Table 2: Chemical Analysis of the Distillate and Concentrate Streams 

Combined Data from Three MVR’s

17
3

List of Photographs

Photo 1: Gas Driven Generator 10

Photo 2: Influent Storage Reservoir 10

Photo 3: Flash Mixer and Clarifier 12

Photo 4: Flash Mix Caustic Addition 12

Photo 5: Chemical Storage Facility 12

Photo 6: Details of the Lamella Clarifier 12

Photo 7: Filter Presses and Tote Systems 12

Photo 8: Plate and Frame Filter Press 13

Photo 9: Typical Dewatered Sludge Cake 13

Photo10: View of a Single Nomad System 13

Photo 11: Pretreatment (L), Engine (C), Evaporator (R) 13

Photo 12: Compressor Engine Skid 15

Photo 13: Evaporator Plates 15

Photo 14: Evaporator Skid 15

Photo 15: Anti-foam and Corrosion Control with Pretreatment Skid in 

Background

16

Acronym and Abbreviations 

bbl Barrel = 42 US gallons

BETX Benzene, ethylbenzene, xylene, toluene

BOD Biochemical oxygen demand

COD Chemical oxygen demand

kWh Kilowatt-hour

mg/l milligram per liter, approximately part per million by weight

MVR Mechanical vapor recompression

POTW Publicly Owned Treatment Works

SCF cubic foot of natural gas at standard temperature and pressure

TDS Total dissolved solids (mg/l)

TOC Total organic carbon 

TPH Total petroleum hydrocarbons
4

1 Abstract

This report is part of an overall effort to advise and support the natural gas industry in 

the evaluation and selection of treatment equipment and processes for the treatment and 

reuse of water used and generated by the industry. 

Extensively used by the food, chemical, and pharmaceutical industries, the 

mechanical vapor recompression (MVR) process is viewed by a number of shale gas 

companies as one of the most reliable methods of recovering demineralized water from 

concentrated brines. For this reason, Devon Energy has supported the demonstration of 

three modular NOMAD units that are manufactured by Aqua-Pure Ventures and operated 

in the field by Fountain Quail Water Management. This report presents process data on a 

commercial-scale (6,000-6,800 bbl/day) mechanical vapor recompression distillation 

(MVR) processing plant treating shale gas hydro-fracture flowback and produced water in 

North Central Texas (Barnett shale region). Process data were collected during a 60 day 

period during summer 2011. The pretreatment at this plant included caustic addition and 

clarification for total suspended solids and iron control. Pretreated water was distilled with 

three Aqua Pure MVR units, each rated at 2,000-2500 bbl/day. Distilled water recovery 

averaged 72.5% of the influent to the MVR’s The influent total dissolved solids (TDS) fed 

to the MVR’s averaged just under 50,000 mg/l. More than 99% of the TDS was captured 

in the concentrate stream. The distillate averaged about 171 mg/l TDS. The fate of 

multivalent cations, total petroleum hydrocarbons (TPH), and benzene, toluene, 

ethylbenzene and xylenes (BTEX) throughout the treatment system was determined. Most 

of the iron (90%) and TPH removal (84%) occurred in the clarification step. The removal of 

iron, magnesium, calcium, barium, and boron from the distillate exceeded 99%. BTEX 

removal from the distillate exceeded 95%. The power at the facility was provided by two 

natural gas generators, plus the three generators on the MVR units, making isolation of the 

MVR energy requirements problematic. Best-fit correlations between treated water and 

distillate production versus total plant utilization of natural gas indicated that there was a 

base power load throughout the facility of about 120-140 thousand standard cubic feet of 

gas per day. Approximately 48 SCF per barrel influent water treated (or 60.5 SCF per 

barrel distillate produced) was required; this represents an energy cost of less than 25 

cents per barrel treated and about 30 cents per barrel of distillate product generated 

(assuming a natural gas cost of $5/mmBtu). Performance in terms of water recovery and 

product water quality was stable throughout the 60-day test. The treatment process is 

available throughout the shale gas industry; Fountain Quail Water Management provides 

the complete equipment package and operation of the integrated MVR treatment facility on 

a price per barrel basis. Cost factors and approximate pricing for example applications are 

included in the report. 
5

2 Introduction

As shale gas emerges as one of the world’s most abundant, affordable and cleanburning sources of energy, sustained growth in the development and production of these 

resources will require intensive levels of sourcing and management of water. In most 

shale plays, hydraulic fracturing is a necessary step for initiating economical energy 

production. During the hydraulic fracturing process, between 1 and 4 million gallons of 

water are mixed with sand (which serves as propant) and chemical additives (e.g. friction 

reducer polymers, corrosion inhibitors, scale inhibitors, biocides, etc.), and the mixture is 

injected “down hole” as a necessary step in the well completion process. Vertical wells 

(representing less than 10% of the wells installed in the Barnett Play) require 

approximately 1 million gallons and horizontal wells (representing 90% of the wells) require 

3-4 million gallons according to a survey among Barnett Shale Producers (Galusky, 2007). 

About 10 to 50 percent of this water is recovered during the months that follow a well 

completion. The recovered fluid can contain elevated concentrations of dissolved salt 

(picked up from mineral solubilization), suspended solids, oils and greases, soluble 

organics, and low concentrations of chemical additives. Therefore, recovered flowback 

water and produced water streams present a water management challenge, as well as a 

significant cost factor in the operation of the well. 

The dimensions of water management for each shale gas developer can be more 

clearly seen when considering that current trends favor the construction and completion of 

10 to 30 wells from one or two well pads in each well field (an effort requiring 1-3 years). 

The installation of dozens or hundreds of well fields within a development area that is 

roughly the size of a county, could require more than a decade. Under full scale 

development, hundreds of millions of gallons of fresh water must be found and transported 

to well sites each year using tens of thousands of truckloads. In addition, the management 

of flowback water and produced water collected from an ever growing population of 

completed wells requires options for the transportation and management of thousands of 

truckloads of brine that usually range in salt content from 30,000 mg/l of TDS (as seen in 

early flowback water) to more than 150,000 mg/l TDS (as seen in many produced water 

streams). 

Shale gas developers of the Barnett Shale and Marcellus Shale regions have long 

recognized the potential benefits of reusing flowback water and produced waters for 

conducting hydraulic fractures of future shale gas well completions. The practice of water 

reuse usually involves collecting and treating the flowback water from a completed shale 

gas well and blending that water with supplemental freshwater for use in completing 

another shale gas well. Benefits of reuse include: 1) The reduction the shale gas 

industry’s demand for fresh water supplies (water conservation is of high importance to 

drought prone regions such as the Barnett Shale); 2) Significant reduction in volumes of 

brine requiring final disposal (a particularly attractive benefit to Marcellus Shale companies 

in Pennsylvania that lack ready access to deep well injection facilities and are prevented 

from obtaining permits for controlled brine discharges to publicly owned treatment works or 

POTW’s); 3) A significant decrease in water transport truckloads; and, 4) Improved 

environmental factors that arise from decreased trucks on the road (e.g. traffic congestion, 

emissions, carbon footprint, etc.). 
6

In view of these advantages, the shale gas industry has explored various options for 

brine water reuse. In principle, the flowback water and produced water of a completed 

well are collected, treated and blended with supplemental fresh water at the impoundment 

that supplies water for the next hydraulic fracture completion of another shale gas well. In 

the area of treatment for purposes of shale gas water reuse, there are mainly two schools 

of thought that exist in the industry. One school of thought says: “Clarify the brine and 

control constituents that cause operational problems without removing the salt.” This 

approach applies primary treatment (settling and filtering) and chemical disinfection for the 

control of suspended solids, oils and greases, bacteria and scale forming ions (i.e. 

constituents that potentially interfere with equipment and infrastructure maintenance with 

no separation of salts (desalination) prior to reuse. Currently, this approach is being used 

within the Marcellus Shale as the predominant shale gas water management practice. In 

practice, flowback and produced waters are processed using primary treatment at the 

wellhead or in near-field locations at a central processing facility; the clarified brine is then 

transported to the next shale gas well completion site where the brine is blended with 

freshwater (at a ratio of about 3-5:1) resulting in a water mixture with salinity of greater 

than 5,000 mg/l TDS (a salt concentration level of regulatory concern in most states). In 

working with brine blends, water conveyance and storage impoundments need to be of 

higher integrity in construction to reduce the likelihood of release of mobile salts (e.g. 

sodium chloride) into the environment; this, of course, adds to the cost for these 

components. 

The other school of thought says: “Recover demineralized water from the brine for 

reuse so that water-blend handling equipment and storage structures do not have to be 

designed to control salt releases.” This approach requires much of the above processing 

for the removal of suspended solids, oils and greases and scale forming constituents plus 

the treatment step of demineralization which results in the recovery of a low-TDS water 

stream that can be easily handled, transported, stored and blended for reuse in hydraulic 

fracturing. The advantage of this approach would be reduced regulatory concern over 

minor water releases that might occur with water handling, conveyance and storage 

systems since the salt content of water blends would be well below 2,000 mg/l TDS. 

Although demineralization of water adds a cost for flowback and produced water 

treatment, this approach does allow maximum latitude in using low-cost storage systems 

and piping systems for inter-field or near-field management of water associated with shale 

gas developments. 

Demineralization of shale gas waters can be performed by several types of processes, 

including membranes and thermal treatment systems; these classes of separations have 

been considered by shale gas developers due to their successful historical implementation 

in the desalinization of sea water and their extensive use for various industrial applications. 

Membrane-based processes, such as reverse osmosis (RO), have been evaluated, but 

these processes are limited in application to waters of less than 40,000 mg/l TDS (CSM, 

2009; Gaudlip, et al., 2008) if water recoveries of more than 60 percent are to be realized 

at reasonable pressure drops under 900 psi. Since a good fraction of flowback streams 

and produced waters can be far higher than 40,000 mg/l TDS, it is necessary to consider 

alternative demineralization processing based on thermal-mechanical separation. 

One of the most efficient thermal processes used for the recovery of water from brine 

streams is the mechanical vapor recompression process (MVR). Extensively used by the 
7

food, chemical, and pharmaceutical industries, the mechanical vapor recompression 

(MVR) process is viewed by a number of shale gas companies as one of the most reliable 

methods of recovering demineralized water from concentrated brines. At a centralized 

brine processing location accepting flowback and produced waters from multiple well 

fields, the MVR process offers the potential of recovering substantial volumes of 

demineralized water from brine that can widely vary in quality. Demineralized water that 

contains less than 500 mg/l of TDS can then be conveyed and stored for future reuse with 

minimal regulatory concern for salt release to the environment. For this reason, Devon 

Energy, one of the largest natural gas developers of the Barnett Shale, has supported the 

demonstration of the MVR technology at a multiple locations over the past seven years as 

a part of a larger development effort to improve its near-field water management systems. 

The MVR system selected for evaluation includes the modular, mobile NOMAD skid units 

that are manufactured by Aqua-Pure Ventures and operated in the field by Fountain Quail 

Water Management. 

The purpose of this project was to systematically document the field performance of 

the NOMAD MVR system in the demineralization of shale gas waters in a near-field brine 

processing facility that was owned by Devon Energy and operated by Fountain Quail. 

Performance characterization included determination of mass flows, energy flows, fate of 

constituents of interest, product water yield and product water quality. Importantly, testing 

under real world conditions allowed the determination of actual field conditions (including 

feed water quality) on the stability and performance of the entire MVR system, including 

pretreatment and thermal skid units. Test plan development, coordination and data 

compilation and analysis were all coordinated by the Gas Technology Institute to provide a 

third party assessment of the MVR system in the demineralization of a blend of flowback 

and produced water from shale gas well fields in the Barnett. This report has been 

prepared by GTI to provide managers and engineers with a technical information base for 

decision making regarding the value and potential role of the MVR process in the long 

range management of brines and salts throughout the water-based life cycle of each shale 

gas development area. 

Specifically, this report presents process data on a full-scale (6,000-6,800 bbl/day) 

mechanical vapor recompression distillation (MVR) processing plant (Maggie Spain site) 

treating shale gas hydro-fracture flowback and produced water in North Central Texas 

(Barnett shale region). The Maggie Spain site is owned by Devon Energy Corporation and 

operated by Fountain Quail Management, a joint venture established between Aqua Pure 

and the Ellenburg Group. The processes at this site are designed to concentrate solids for 

deep well injection, and to maximize salt-free water for reuse. The treatment philosophy 

and management goals represent a proactive and progressive example of environmental 

stewardship in the shale gas industry. 
8

3 Background

Mechanical vapor recompression is a highly efficient distillation process wherein a 

mechanically-driven blower or compressor is used to increase the pressure of the vapor 

that is produced from the boiler in order to improve heat transfer efficiencies. An increase 

in the water vapor pressure increases the condensation temperature of the steam 

rendering it useable for heating the original mixture (in the boiler) in a heat transfer device

or heat exchanger. This results in the operation of a distillation process at a substantially 

lower energy demand. 

Mechanical vapor recompression has become a standard method of distillation since 

its commercial introduction in the 1960’s. The process has been employed at thousands 

of facilities for the desalination of sea water (Veil, 2008), the crystallization of sugars in the 

food industry, dewatering of products in the chemicals and pharmaceuticals industries 

(Becker and Zakak, 1985), and more lately, in the recovery of industrial wastewaters. 

The major advantage of mechanical recompression over conventional distillation is the 

ability to recycle the latent heat of flashed vapors to the bottom fluids, saving 10-15 % of 

the total energy of distillation. The recompressed vapors are saturated homogeneous 

fluids in thermodynamic equilibrium. Becker and Zakak (1985) describe three methods of 

application, recompression of the top vapors, the bottom vapors, or the intermediary vapor. 

The choice of the distillation style is dependent on the thermodynamics of the distillation 

components, and the goals of product recovery. The authors present a series of selection 

rules for the compressors. Economic case studies are presented for xylene recovery and 

isobutene extraction at refineries. Cost savings of up to 47% are claimed with payback 

periods of 1 to 2 years. 

Leatherman (1983) reported radical energy savings over conventional distillation by 

incorporation of MVR technology to the recovery of uranyl nitrate in uranium processing. 

Steam generation at the plant decreased by 50% and cooling water requirements 

decreased by 35% compared to conventional distillation. Shake-down tests required about 

133 kWh/1000 gallons distillate generated (5.6 kWh/bbl). Full production energy 

requirements were about 157 kWh/1000 gallons (6.6 kWh/bbl).

Concurrent Technologies (2001) described the advances in MVR technology that 

allow for the use of the Hadwaco process for treatment of metal finishing wastewater. 

These include more robust compressor screw designs, new inexpensive materials for heat 

exchanges to better collect low grade heat, and new evaporator designs with improved 

scale control. Advantages for the environmental arena are 1) extreme purity of distillate, 

2) concentration of all non-volatile components and 3) recovery of solids for recycle or 

disposal. The process allows for design of nearly complete recycle of process water. 

Potential disadvantages are high maintenance and operations costs, corrosion control, 

scaling, and cooling water availability.

In the follow-up to the Concurrent Technologies (2001) test plan, Gallerani, Brown, 

and Moore (2002) reported test results at a copper finishing plant producing 116,600,000 

liter/year (734,000 bbl/yr) wastewater. Influent to the MVR during the test period ranged 

from 600 to 2,600 mg/l TDS. Distillate recovery exceeded 95% of the influent. Copper 

and sulfate capture exceeded 98%, allowing recovery of 23,900 kg (53,600 lb) copper 

metal per year. The energy use for generated distillate was 13.9 kWh/1000 liters (6.3 

kWh/bbl). 
9

Veil (2008) presented a cursory evaluation of the Aqua Pure MVRs at the Devon 

Energy water reclamation facility in Decatur, Texas. This site (also called the “Maggie 

Spain Facility” which is the subject of the present report) treats flowback water and 

process water from Devon’s shale gas wells located at multiple well fields in Denton 

County. A general flowchart of the process was presented by Veil (2008) but previous 

literature has been limited in the amount of performance data that has been available on 

MVR units treating shale gas brines. This report is aimed at presenting performance 

information that addresses this information gap. 

4 Maggie Spain Facility 

The sections to follow in this report provide a more detailed description of the Maggie 

Spain process train and its performance during a 2-month period when samples and 

measurements were taken to characterize mass and energy flows throughout the entire 

treatment system. The Maggie Spain Facility is comprised of an influent impoundment 

and a water preconditioning train followed by multiple mechanical vapor recompression 

(MVR) modules. The MVR’s are operated in parallel to generate a demineralized product 

water stream and a concentrate stream. The diluate, representing >70% of the water flow 

is discharged to a product water impoundment. The concentrate, representing less than 

30% of the water flow and greater than 90% of the TDS is collected in effluent storage 

tanks for future disposal. Figure 1 shows a schematic of the entire Maggie Spain 

treatment facility incorporating the MVRs. This diagram shows the locations in the 

flowsheet where water samples were taken for analysis (sampling twice weekly). 

Analyses included conductance, total organic carbon, BTEX (benzene, toluene, ethyl 

benzene, and xylenes), TPH (total petroleum hydrocarbons), total heavy metals, total 

dissolved solids (TDS), suspended solids, pH, alkalinity, sulfate, total ammonia, and 

phosphorus. 

All of the energy required by the facility is supplied by natural gas that is provided by 

the shale gas wells of Devon Energy. The electricity required for pretreatment, and 

general site needs is supplied by two natural gas driven generators (Photo 1). Each 

NOMAD MVR skid is powered by an internal combustion engine fueled by natural gas 

(each engine capable of delivering up to 700 hp). Total energy demand measurements 

were obtained from daily readings of the natural gas utilization at the facility. 

4.1 Preconditioning

For the preconditioning portion of the facility, the treatment objective is to provide 

suspended solids removal, oil & grease control, iron removal, and calcium-stable water. 

Water is delivered daily by truck at a rate of approximately 4,000 to 6,000 bbl/d to a 1.4 

acre storage reservoir (Photo 2). The chemical analysis of the water leaving the reservoir, 

(representing influent water to the clarifier) is presented in Table 1. The average total 

dissolved solids are about 50,000 mg/l. The raw water contains a number of scale forming 

cations, including calcium, iron, strontium, magnesium and barium. Small amounts of total 

petroleum hydrocarbons and BTEX are also present. 
10

Table 1: Influent and Post Clarifier Water Analysis

All units (mg/l) except pH

And Conductance (mS/cm)

Influent Water Post Clarifier 

Average Median Standard 

Deviation

Average Median Standard 

Deviation

Specific Conductance 55,835 55,650 24,890 57,989 61,050 24,243

Total Dissolved Solids 49,550 44,900 10,959 49,133 46,900 9,921

Total Suspended Solids 1,272 357 3,443 140 132 45

pH NA 6.9 6.7 - 7.7 NA 3.7 3.1 - 4.6

Alkalinity 405 385 126 12 4 14

Total Organic Carbon 42 12 118 10 9 5

TPH* 388* 19 1,363 5 4 2

BTEX 3.3 2.9 1.4 2.3 2.1 0.8

Ammonia 84 84 26 81 84 24

Sulfate 309 316 153 221 205 123

Phosphorus 3 3 2 2 2 1

Barium 15 7 19 13 6 17

Boron 17 18 4 16 16 3

Calcium 2,916 2,570 975 2,876 2,705 922

Iron 28 27 10 3 2 3

Lithium 12 11 3 12 11 3

Magnesium 316 291 131 319 296 114

Potassium 484 296 524 504 349 494

Sodium 10,741 10,700 3,622 12,400 12,100 2,821

Strontium 505 467 182 528 483 161

Note(*) TPH data overwhelmed by a single event of 5,893 mg/l. 

The TPH average is 38 ± 43 when this event is disregarded.

Photo 1: Gas Driven Generator Photo 2: Influent Storage Reservoir
11

3 MVR Units

Flowback Delivery Storage Reservoir Flash Mixer

Lime and 

Polymer, pH 10 

Lamella

Separator

Concentrated Brine 

to Deep Well or 

Reuse

Surge Tank 

Acid to pH 4

2 Filter Presses

Product Water 

Storage

Product Water to 

Reuse or Discharge

Sludge Cake to Landfill

Filtrate 

Influent 

Sample

Post 

Clarifier 

Sample

Distillate 

Samples

(3)

Condensate 

Samples (3)

Figure 1: MVR Process Flow Sheet, Maggie Spain Facility
12

 Water from the storage reservoir is sent to a 

process unit containing a flash-mix chamber and 

a lamella clarifier (Photo 3). Caustic (NaOH) is 

added at the flash mixer (Photos 4 and 5) to 

increase in the pH of the water to about pH10. 

The shift in pH causes much of the iron to 

precipitate. Polymer is occasionally added to 

aide in the coagulation of the solids. 

Precipitated iron and other suspended solids 

are removed across a lamella plate clarifier 

(Photo 6). The clarifier removes about 90% of 

the suspended solids, including 90% of the 

influent iron. The chemical analysis of the post 

clarifier water is presented in Table 1.

The solids from the clarifier are dewatered 

with a pair plate and frame filter presses (Photos 

7 and 8). The solids contribution from the 

clarifiers to the filter is about 2,500 dry pounds 

per day. 

The cake solids produced (Photo 9) from the 

presses are about 20-25% dry matter, yielding a 

wetted solids stream of 10,000 to 12,500 pounds 

wet solids per day. A 20 yard tote is removed 

from the site about once per week. The solids 

are sent to a landfill. 

Clarified water is sent to a surge tank where 

the pH is adjusted to pH 4 to stabilize the scale 

forming cations, such as calcium. The pH 

adjusted water is the feed to the MVR units.

Photo 5: Chemical Storage Facility

Photo 3: Flash Mixer and Clarifier

Photo 6: Details of the Lamella

Clarifier

Photo 4: Flash Mix Caustic Addition

Photo 7: Filter Presses & Tote 

Systems
13

4.2 Mechanical Vapor Recompression

The Maggie Spain facility has three mechanical vapor recompression modules (Aqua 

Pure NOMAD systems) that are powered by natural gas, including the boiler that is used to 

bring the module up to temperature during startup and the 700 hp natural-gas-fueled 

internal combustion engine that drives the compressor. Electricity used for ancillary 

lighting, controls and data acquisition is supplied by one of the on-site generators (Photo 

1). The footprint of the NOMAD facility is modest; a three NOMAD processing facility 

occupies an area of about 250’ x 250’ (about 1.4 acres). Each module (Photo 10) has a 

processing capacity of up to 2,800 bbl/d of influent brine. 

Each Aqua Pure NOMAD system consists of chemical conditioning plus three skids.

1) Pretreatment Skid; 2) Engine Skid; and, 3) Evaporator Heat Exchanger Skid. The 

chemical conditioning consists of anti-foam agents and corrosion control. The pretreatment 

skid provides 5μ bag filtration and pre-heating economizers. The engine skid houses a 

mechanical compressor. The evaporator skid (Photo 15) provides the liquid-vapor heat 

exchangers, evaporator tank, and distillate collection tank. A simplified process flow 

diagram for the Aqua Pure MVR is presented in Figure 2 (Razzaghi and Spiering, 2002). 

Photo 8: Plate and Frame Filter 

Press

Photo 9: Typical Dewatered Sludge 

Cake

Photo10: View of a Single Nomad 

System

Photo 11: Pretreatment(L), Engine (C), 

Evaporator (R)
14

The process is initiated by heating a portion of water from the distillate collection tank 

with an auxiliary start-up boiler. When the process comes up to temperature, the boiler is 

extinguished. 

The mechanical compressor (Photo 12) is fed a balanced mixture of vapor (fresh 

distillate) from the vapor separating concentrate tank and water (existing distillate) from the 

distillate collection tank. The compressor increases the fluid pressure creating a saturated 

vapor. 

The saturated vapor enters a liquid/vapor heat exchanger (Photo 13) on the 

exchanger skid (Photo 14). The hot side of the exchanger is the saturated distillate vapor. 

The cool side of the exchanger is concentrated liquor fed from the vapor separating 

concentrate tank. The process is designed to vaporize about 10% of the concentrate 

liquor.

Mechanical 

Compressor

Liquid-Vapor

Heat Exchanger

Distillate Tank

Start-up Boiler

Start-up 

Feed 

Condensing 

Steam Return 

Distillate 

Return 

Distillate 

Cooling 

Vapor SeparatorConcentrate Tank 

Economizers

PreHeated 

Feed 

Vapor 

Feed

Concentrate 

Discharge 

Concentrate 

Liquor

Concentrate10

% Vapor 

Distillate

Discharge 

Figure 2: Simplified Flow Diagram for the Aqua Pure Mechanical

Vapor Recompression Process
15

The partially vaporized concentrate stream returns to the vapor separating concentrate 

tank. Vapor in this tank is the fresh distillate fed to the mechanical compressor in the 

continuing cycle. 

When the distillate recovery tank is sufficiently full, or the concentrate stream reaches 

a preset conductivity, then a portion of the distillate and/or the concentrate liquor is 

discharged. The discharged liquids pass through independent economizers to recover 

some of the sensible heat in these streams. 

Photo 13: Evaporator Plates Photo 14: Evaporator Skid

Photo 12: Compressor Engine Skid
16

The cool side of the economizers is the filtered feed and chemically conditioned water 

from the pretreatment skid (Photo 15). The preheated feed stock enters the vapor 

separating concentrate tank and becomes part of the concentrate/vapor distillate cycle. 

Technology features of the Aqua Pure MVR system represent an innovative adaption 

of conventional MVR processing to the highly-aggressive nature of shale gas waters that 

are characterized by the high levels of scale forming constituents (such as calcium and 

barium). A detailed discussion of these features is provided in a recent SPE article 

authored by Aqua Pure staff (Horner, et al., 2011) (see Appendix). 

4.3 MVR Process Evaluation Results

Maggie Spain process facility was monitored during a sixty day period during between 

June and August, 2011. Flow rates to each MVR and total natural gas utilization were 

measured daily. Water samples were collected twice weekly so that water chemistry data 

were obtained for eighteen of the sixty days. Chemical analyses included total dissolved 

solids, selected organic 

parameters, pH, and a broad 

range of cations. Summary 

data for influent to the MVR’s 

were presented in Table 1 

(clarifier effluent). Summary 

data for the effluent (distillate 

and concentrate streams) from 

the MVR’s are presented in 

Table 2.

The purpose of the 

mechanical vapor 

recompression process is to 

produce salt enriched brine 

(concentrate) and salt-free 

distillate. Cursory examination 

of Tables 1 and 2 shows this 

goal was accomplished. The 

average influent water 

contained about 45,000 mg/l TDS, the distillate contained about 1,900 mg/l, and the 

concentrate contained about 168,000 mg/l. 

Figure 3 is an example of TDS data for the influent, distillate and concentrate collected 

for Nomad No. 3 over sixty days. Data from the other two units was very similar (not 

presented). The overall performance of the MVR’s appeared very uniform throughout the 

entire sampling period. 

Photo 15: Anti-foam and Corrosion Control with 

Pretreatment Skid in Background
17

Table 2: Chemical Analysis of the Distillate and Concentrate Streams 

Combined Data from Three MVR’s

All units (mg/l) except pH

And Conductance (mS/cm)

Nomad MVR Distillate* Nomad MVR Concentrate

Average Median Standard 

Dev

Average Median Standard 

Dev

Specific Conductance 267 161 280 162,818 158,500 83,327

Total Dissolved Solids 171 103 179 168,465 162,000 29,239

Total Suspended Solids 9 4 12 617 519 319

pH NA 10.7 10.5-10.9 NA 6.7 6.3-6.8

Alkalinity 263 248 85 162 143 73

Total Organic Carbon 22 16 17 12 12 4

TPH 4.6 4.0 2.3 4.3 4.0 1.1

BTEX 0.2 0.1 0.2 0.0 0.0 0.0

Ammonia 68 64 26 113 114 50

Sulfate 6 5 2 887 793 631

Phosphorus 0.1 0.1 0.2 7 6 8

Barium 0.1 0.1 0.0 27 5 48

Boron 0.4 0.4 0.1 63 62 13

Calcium 3.2 0.8 6.8 9,699 8,960 2,485

Iron 0.1 0.1 0.0 4 2 4

Lithium 0.1 0.1 0.0 42 38 11

Magnesium 0.4 0.1 0.8 1,132 1,055 355

Potassium 0.5 0.1 1.4 2,028 1,675 1,576

Sodium 14.3 3.6 31.6 41,302 39,000 8,046

Strontium 0.5 0.1 1.0 1,739 1,735 430

*Distillate Concentration calculated from Specific Conductance

0

25,000

50,000

75,000

100,000

125,000

150,000

175,000

200,000

0 10 20 30 40 50 60

Day TDS (mg/l)

Post Clarifier (MVR Influent)

Concentrate Nomad No.3

Distillate Nomad No.3

Figure 3: Daily Operation Data for Nomad #3
18

The overall water balance for typical operation was generated by examining distribution of 

water between the distillate and concentrate of the individual MVR units. Figure 4 is a plot 

of distillate and concentrate volume versus the volume fed to each unit. The slope of each 

line represents the fraction of the influent recovered. The MVRs, as operated in this 

process period, generated 72.5% distillate and 27.5% concentrate. 

The overall salt balance for typical operation was generated by examining the 

distribution of TDS between the distillate and concentrate of the individual MVR’s. This 

evaluation is presented in Figure 5. The slope of each line represents the fraction 

recovered in that process stream. The plot shows that the concentrate reliably contains 

99.75% of the total salts while only 0.25% remains in the distillate.

Distillate

 Concentrate

Flow Distirbution

 Distillate = 72.5%

 Concentrate = 27.5% 

0

500

1,000

1,500

2,000

2,500

0 500 1,000 1,500 2,000 2,500 3,000

Barrels/Day Fed Per MVR Unit Barrels/Day Recovered Per MVR.

Nomad 2 Distillate

Nomad 3 Distillate

Nomad 9 Distillate

Nomad 2 Concentrate

Nomad 3 Concentrate

Nomad 9 Concentrate

Figure 4: Water Distribution between Distillate and Concentrate During 60 Day 

Sample Period
19

4.4 Energy Utilization 

Total daily natural gas consumption (SCFD) was measured for the entire Maggie 

Spain facility. Since energy consumption represents natural gas use for the entire plant, 

characterizing natural gas demand for individual MVR units becomes challenging; for this 

reason, total natural gas demand was plotted as a function of overall influent loading and 

product water yield to determine the overall energy requirement for the facility (including 

MVR operation plus electricity generation). Figure 6 is a graph of total SCF gas utilization 

as a function of treated water or distillate generated. The plots appear linear with respect 

to either total volume of water treated, or the volume of distillate produced. The slopes of 

the lines in this plot indicate that the process requires about 48 SCF/bbl influent or 60.5 

SCF/bbl distillate produced above the base loading. Some of the scatter in the data is 

inevitably due to other process loads on the generators, such as drive motors and 

hydraulic pumps on the clarifier and filter press skids, site lighting, and miscellaneous 

office and maintenance activities. The raw gas numbers also include inefficiencies in 

electricity generation and transmission. Assuming that the field efficiency of the gas 

generators is about 35% to produce the required electricity, then the value of 60.5 SCF/bbl 

distillate is equivalent to 6.4 kWh/bbl distillate. This is convincingly within the range of 

results reported for electrically driven MVR’s (Letterman, 1983; Gallarani et. al., 2002). If 

the apparent base load is added to the incremental processing energy requirements, the 

overall treatment requires 72 SFC per barrel treated, or 100 SCF per barrel distillate 

produced. 

Some of the scatter in the data is inevitably due to other process loads on the 

generators, such as drive motors and hydraulic pumps on the clarifier and filter press 

Figure 5: Distribution of Dissolved Salts between the 

Distillate and the Condensate Streams During 60 Day Sample 

Period

TDS Distribution

0.25% Distillate

99.75% Concentrate 0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

0 10,000 20,000 30,000 40,000 50,000 60,000

Pounds Salt (TSD) Per Day in Feed TDS in Concentrate or Distillate (lb/day)

Nomad 2 Distillate

Nomad 3 Distillate

Nomad 9 Distillate

Nomad 2 Concentrate

Nomad 3 Concentrate

Nomad 9 Concentrate
20

skids, site lighting, and miscellaneous office and maintenance activities. The raw gas 

numbers also include inefficiencies in electricity generation and transmission. Assuming 

that the field efficiency of the gas generators is about 35% to produce the required

electricity, then the value of 60.5 SCF/bbl distillate is equivalent to 6.4 kWh/bbl distillate. 

This is convincingly within the range of results reported for electrically driven MVR’s 

(Letterman, 1983; Gallarani et. al., 2002). If the apparent base load is added to the 

incremental processing energy requirements, the overall treatment requires 72 SFC per 

barrel treated, or 100 SCF per barrel distillate produced. 

4.5 Fate of Various Chemical Constituents 

The following six figures summarize the fate of important environmental constituent at 

various points in the Maggie Spain pretreatment and MVR processing. Data for these 

figures were generated from Tables 1 and 2.

Figure 7 re-examines the overall fate of total dissolved solids. The storage reservoir 

and clarification have no affect on TDS concentrations. The MVR’s concentrate the TDS, 

removing most salts from the distillate stream.

Figure 8 is a summary of the fate of calcium, magnesium, and strontium. These are 

potential scale forming components. This figure shows that the fate of these compounds 

is similar to that of the total dissolved solids. The storage reservoir and clarification have 

no affect on calcium, magnesium, and strontium concentrations. The MVR’s concentrates

these cations and removes them from the distillate stream.

Figure 6: Daily Natural Gas Demand Versus Influent 

Loading and Distillate Product Yield (Composite of Three 

MVR Units)

Natural Gas Utilization

SCF = 48 x Barrels + 120,000

SCF = 60.5 x Barrels + 143,000

0

100,000

200,000

300,000

400,000

500,000

0 2,000 4,000 6,000 8,000

MVR Loading or Distillate Yield (Barrels/Day)

Natural Gas Demand, SCFD

Treated Influent

Distillate Yield
21

Figure 9 is a summary of the barium, boron, and iron in the water. Barium and boron 

follow the familiar trend for TDS and are similar to calcium, magnesium, and strontium. 

Total Dissolved Solids

168,500

+/-

29,200

1,880

+/-

1470

49,130

+/-

9,900

49,550

+/- 

11,000

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

180,000

Influent Post Clarifier Distillate Concentrate

TDS (mg/l)

Figure 7: Fate of Total Dissolved Solids in the Maggie Spain Facility

Calcium, Magnesium, Strontium 9,700

+/-

2,500

4

+/-

1

2,900

+/-

900

2,900

+/-

1,000

1,150

+/-

350

0.4

+/-

0.1

320

+/-

120

320

+/-

130

1,740

+/-

430

0.5

+/-

1.0

530

+/-

160

500

+/-

180

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

Influent Post Clarifier Distillate Concentrate

Cation Concentration (mg/l) . 

Calcium

Magnesium

Strontium

Figure 8: Fate of Calcium, Magnesium, and Strontium in the

Maggie Spain Facility
22

The pretreatment has little affect, and the ions are captured in the MVR condensate 

stream. Iron, however, is precipiated by the initial caustic addition in the rapid mix tank 

and much (90%) is removed by the clarifier. Any remaining iron is prefferentially removed 

in the MVR condensate.

Suspended solids removal data are reproduced in Figure 10. About 90% is removed 

by the clarifier. The remaining suspended solids are removed to the concentrate stream. 

It is also possible that certain cations, such as barium and strontium, reach saturation 

equilibrium within the MVR concentrate stream and generate excess suspended material. 

The fate total petroleum hydrocarbons (TPH) is apparently intimiately tied to the initial 

suspended solids (Figure 11). More than 84% is removed by clarification, and presumably 

is removed with the sludge cake from the filter press. Note that TPH data are 

overwhelmed by a single event of 5,893 mg/l. The TPH average is 38 ± 43 when this 

event is disregarded. Figure 11 presents the amended value of 38 mg/l influent.

Barium, Boron, Iron

63

+/-

13

0.1

+/-

0.03

13

+/-

17

15

+/-

19

27

+/-

48

0.4

+/-

0.1

16

+/-

3

17

+/-

4

4

+/-

4

0.1

+/-

0.05

3

+/-

3

28

+/-

10

0

10

20

30

40

50

60

70

Influent Post Clarifier Distillate Concentrate

Cation Concentration (mg/l) . 

Barium

Boron

Iron

Figure 9: Fate of Barium, Boron, and Iron in the Maggie Spain Facility
23

Total BTEX (benzene, toluene, ethylbenzene, and xylene) represents a volatile fraction of 

the organic matter in the water stream. Some (30%) of the BTEX is removed between the 

influent and the end of the clarification process. Presumably, much of this removal occurs 

at the rapid mix tank from suface volatility. Much of the remaining BTEX is removed 

(additional 90-95%) in the MVR process. It is likely that this organic component is 

volatilized and expelled at degassing or pressure relief valves throughout the separator 

tank. Notably, the remaining BTEX is prefferentially found in the distilate, indicating that 

these volatile compounds remain with the vapor side of the MVR process.

Suspended Solids

1.270

+/- 

360

140

+/-

130

9

+/-

4

620

+/-

320

0

200

400

600

800

1000

1200

1400

Influent Post Clarifier Distillate Concentrate

Suspended Solids (mg/l)

Figure 10: Fate of Suspended Solids in the Maggie Spain Facility

Figure 11: Fate of Total Petroleum Hydrocarbons in the Maggie Spain 

y

Total Petroleum Hydrocarbons

4

+/-

4

5

+/-

2

5

+/-

2

38

+/- 

43

0

5

10

15

20

25

30

35

40

Influent Post Clarifier Distillate Concentrate

Total Petroleum Hydrocarbons (mg/l).
24

5 Discussion 

Mechanical vapor recompression has been touted as an attractive alternative for the 

treatment of various wastewaters, expecially when water or other resource recovery is 

paramount. This is the case in most Barnett well fields, where fresh water is precious and 

deep well injection is at a premium. 

The Maggie Spain facility discussed in this report is an excellent example of the MVR 

process as it pertains to the shale gas industry. All unit processes are mobile and can be 

operated on natural gas, an obvious advantage in a natural gas field. A case-in-point, this 

facility was moved to a new location prior to the completion of this report.

Advantages of the process are obvious from perusal of the analytical data. Most 

constituants of interest, including trace organics and multivalent metals, are effectively 

removed either in pretreatment, or in the distillation process. The distillate is sufficiently 

pure to be reused in place of fresh process water, or could be discharged to a receiving 

stream with little or no additional conditioning. The concentrate volume represents less 

than 28% of the original volume, resulting in lowered ultimate disposal costs.

One disadvantage of the process is the production of solid waste generated from the 

clarifier solids. This requires some operational expertise and maintenance time, plus 

additional landfill costs. 

The overall treatment (entire facility) requires 72 SFC per barrel treated, or 100 SCF 

per barrel distillate produced. MVR costs are more difficult to detail from the data as 

collected. However, best-fit correlations indicate that there is a base natural gas load to 

the facility requiring 120-140 thousand SCF per day. Energy need per incremental barrel 

of treating influent water and per barrel of distillate generated was estimated to be 48 SCF 

Total BTEX

Benzene, Ethylbenzene, 

Toluene, Xylene

3.3

+/- 

1.4

2.3

+/-

0.8

0.15

+/-

0.17

0.00

+/-

0.01

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Influent Post Clarifier Distillate Concentrate

Total BTEX (mg/l)

Figure 12: Fate of Total BETEX in the Maggie Spain Facility
25

and 60.5 SCF, respectively. Assuming 35% efficiency of electrical power generation from 

natural gas, the energy requirement is about 6.4 kWh/barrel distillate. The Maggie Spain 

Facility energy demand in the processing of shale gas waters appears to be as favorably 

low as the most efficient MVR processing cited in the literature for the treatment of far less 

aggressive waters in terms of organics and scale forming constituents. 

Distilled water recovery averaged 72.5% of the influent to the MVR’s. The influent 

total dissolved solids (TDS) fed to the MVR’s averaged just under 50,000 mg/l. The water 

recovery measured by this evaluation is very close to the 74% water recovery predicted by 

the AquaPure performance literature that graphically presented in Appendix B. 

5.1 Economics

As with the implementation of many water treatment processes, the “per-barrel” pricing 

for shale gas water treated in the mechanical vapor recompression water reclamation 

facility depends upon setting and a number of factors (e.g. overall water quality, average 

salinity of feed waters, actual deliveries of water versus capacity, year-by-year projection 

of flowback and produced water deliveries, etc.) that affect the efficiency and nature of the 

operation. 

Fountain Quail pioneered shale gas water recycling in the Barnett Shale alongside 

some of the earliest pioneers in shale gas development. Devon Energy acquired Mitchell 

Energy and George Mitchell is recognized as the spark that ignited the explosive shale 

development in North America. As such, Fountain Quail had the privilege of working with 

some of the founding pioneers behind the development of the Barnett Shale as a 

commercial gas field. The ability to adapt and react to the changing needs of this rapidly 

developing new industry is critical. 

In order to make recycling cost competitive to disposal in the Barnett Shale, 

recognized as one of the lowest cost shale plays for disposal, Fountain Quail evaluates 

each and every cost associated with recycling in an effort to reduce costs and increase 

efficiency. As such, Fountain Qail often reduces the chemical costs and increase the 

cleaning frequency if this allows a lower cost of operation. A very practical "oilfield-type" 

approach to recycling as been enacted: the equipment must be rugged, durable and easy 

to clean. One cannot afford to complain to the customer when an upset occurs 

(unexpected water composition, etc). The name of the game is to get back operational 

quickly. The equipment is designed with this in mind. For example, compressor efficiency 

was sacrificed by intentionally selecting a low speed engine-driven compressor which is 

very rugged and durable. 

Continuous improvement has also been made. If a certain piece of equipment (e.g. 

pump) causes significant downtime, it is replaced with a different design so that the overall 

runtime and efficiency of the system is improved. By remaining competitive in the Barnett 

Shale, Fountain Quail has developed a wealth of experience and knowledge that has 

allowed the company to expand into the Marcellus and Eagle Ford shales with NOMAD 

technology. For example, a new TSS-removal system called the ROVER has been 

developed, which is able to clean up brine for re-use where customers do not require fresh 

(distilled) water. The design for the ROVER is based on all the years of testing and trials 

of different equipment with Devon Energy in the Barnett Shale. Fountain Quail maintains 
26

that recycling must be simple, rugged, proven and cost-effective. ROVER treatment is 

generally <$1/bbl and NOMAD treatment can be from $3 to $5/bbl, including labor, 

chemical and equipment.

6 Summary

This report is part of an overall effort to advise and support the natural gas industry in 

the evaluation and selection of treatment equipment and processes for the treatment and 

reuse of water used and generated by the industry. 

This report presents process data on a commercial-scale (6,000-6,800 bbl/day) 

mechanical vapor recompression distillation (MVR) processing plant treating shale gas 

hydro-fracture flowback and produced water in North Central Texas (Barnett shale region). 

Process data were collected during a 60 day period during summer 2011.

The pretreatment at this plant included caustic addition and clarification for total 

suspended solids and iron control. Pretreated water was distilled with three Aqua Pure 

MVR units, each rated at 2,000-2500 bbl/day. 

Distilled water recovery averaged 72.5% of the influent to the MVR’s. The influent 

total dissolved solids (TDS) fed to the MVR’s averaged just under 50,000 mg/l. More than 

99% of the TDS was captured in the concentrate stream. The distillate averaged about 

171 mg/l TDS. 

The fate of multivalent cations, total petroleum hydrocarbons (TPH), and BTEX) was 

followed. Most of the iron (90%) and TPH removal ( 84%) occurred in the clarification 

step. The removal of iron, magnesium, calcium, barium, and boron from the distillate 

exceeded 99%. BTEX removal from the distillate exceeded 95%. 

The overall treatment (entire facility) required 72 SFC per barrel treated, or 100 SCF 

per barrel distillate produced. Best-fit correlations between treated water and distillate 

production versus natural gas utilization indicated that there was a base power load 

throughout the facility of about 120-140 thousand standard cubic feet of gas per day. 

Incremental power requirements above the baseline were approximately 48 SCF per 

barrel influent water treated (or 60.5 SCF per barrel distillate produced). 

A new TSS-removal system called the ROVER has been developed, which is able to 

clean up brine for re-use where customers do not require fresh (distilled) water. Fountain 

Quail maintains that ROVER (suspended solids removal) treatment is generally <$1/bbl 

and NOMAD treatment can be from $3-$5/bbl (distillation by mechanical vapor 

recompression), including labor, chemical and equipment.
27

References

1. Becker, F.E., and Zakak, A.I., (1985). Recovering Energy by Mechanical Vapor 

Recompression, Chemical Engineering Progress, Vol. 81, no. 7, pp. 49-53.

2. Concurrent Technologies (2001). Environmental Technology Verification Program for 

the Metal Finishing Pollution Prevention Verification Test Plan for the Evaluation of 

Hadwaco MVR Evaporator for the Metal Finishing Industry, U.S. EPA Testing and 

Verification Program (CR826492-01-0).

3. Drewes, J. (CSM). 2009. An Integrated Framework for Treatment and Management of 

Produced Water. RPSEA Report No. 07122-12.

4. Evaluation of Hadwaco MVR Evaporator for the Metal Finishing Industry. (2004). US 

EPA Testing and Verification Program (VR P2 01-04)

5. Gallerani, P.A., Brown,D., and Moore, G., Concurrent Technologies (2002). 

6. Environmental Technology Verification Program for the Metal Finishing Pollution 

7. Galusky, L.P. and Hayes, T.D. (2011). Feasibility Assessment of Early Flowback 

Water Recovery for Reuse in Subsequent Well Completions. RPSEA Report No. 

08122-05.07. October. 

8. Gaudlip, A.W., L.O. Paugh and T.D. Hayes. 2008. “Marcellus Shale Water 

Management Challenges in Pennsylvania.” Proceedings of the 2008 SPE Shale Gas 

Conference, Fort Worth, TX, November 16-18, Paper No. 119898-PP.

9. Horner, P., B. Halldorson, and J. Slutz. 2011. “Shale Gas Water Treatment Value 

Chain – A Review of Technologies, Including Case Studies.”, Proceedings of the 

2011 SPE Annual Technical Conference and Exhibition, Denver, October 30 –

November 2. 

10. Leatherman, H.R.(1983). Cost Effective Mechanical Vapor Recompression, Chemical 

Engineering Progress, Vol. 79, no. 1, pp. 40-42.

11. Razzaghi, M., and Spiering, R., (2002). Mechanical Vapor Recompression Separation 

Process, U.S. Patent 6,375,803.

12. Veil, J.A., (2008). Thermal Distillation Technology for Management of Produced Water 

and Frac Flowback Water, Argonne National Laboratory, Water Technology Brief # 

2008-1.

Acknowledgements 

The authors express their appreciation to Devon Energy staff -- including Jay Ewing, 

Rusty Werline and Anthony Smith -- for providing technical information on water 

management systems to GTI and for their role in the conduct of tours of the facility for 

visiting stakeholders. The authors also acknowledge Fountain Quail staff -- including 

Brent Halldorson and Jaime Roman -- for their cooperation in obtaining samples and 

information associated with the Maggie Spain Water Reclamation Facility; appreciation is 

also extended to Patrick Horner of AquaPure for his contributions of expertise and 

technical review to this evaluation effort. 
28

Appendix A

Information from Fountain Quail and Aqua Pure on the 

Mechanical Vapor Recompression System

Horner, et al., 2011
SPE 147264 

Shale Gas Water Treatment Value Chain - A review of Technologies, 

including Case Studies 

Patrick Horner, P. Eng., Aqua Pure Ventures and Brent Halldorson, P.Eng., Fountain Quail Water Mgmt and 

James Slutz, SPE, Global Energy Strategies LLC 

Copyright 2011, Society of Petroleum Engineers 

This paper was prepared for presentation at the SPE Annual Technical Conference and Exhibition held in Denver, Colorado, USA, 30 October–2 November 2011. 

This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been 

reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers, its 

officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Society of Petroleum Engineers is prohibited. Permission to 

reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of SPE copyright. 

Abstract 

North American shale gas plays discovered over the past ten years contain an abundant tcf of natural gas, providing a long 

term, low carbon domestic energy source. Drilling and completing techniques developed in the Texas Barnett Shale over the 

past ten years have unleashed an unprecedented new shale gas industry across North America. The most effective completion 

technique is known as hydraulic fracturing (or “fraccing”), a process that involves injecting a large volume (60,000 to 

140,000+ bbls) of fresh water underground to fracture the formation, increasing permeability and thus gas flow. After a frac 

is completed, a large portion of the frac fluid returns to the surface as “flowback” water which contains high concentrations 

of dissolved salts, frac chemicals, and formation minerals. 

The costs and logistics of managing both fresh and flowback water in shale gas plays are problematic. Development of 

North America’s shale gas resources will require well developed water management strategies that include the effective 

implementation of water recycling technologies. Treating flowback for re-use as frac fluid reduces the impact of key issues 

associated with shale gas water management including cost, truck traffic, water availability, and disposal availability. 

Factors including salinity, residual frac chemicals (polymers), H2S, NORM, carbonate scales, iron scales, and sulphate 

scales make the treatment and handling of flowback complex. The overall water management strategy is a function of water 

sourcing and disposal cost and availability, formation geology and how that impacts both flowback water chemistry and frac 

fluid compatibility, the regulatory environment, and the availability of commercialized and cost-effective technology. 

This paper explores the challenges associated with treating shale gas flowback for re-use and evaluates the role and cost 

of available commercial technology. Cases studies of technology applications that have been used during the past seven 

years in major shale basins will be included. 
2 SPE 147264 

INTRODUCTION 

North American shale gas plays discovered over the past ten years contain an abundant tcf of natural gas, providing a long 

term, low carbon domestic energy source. Drilling and completing techniques developed in the Texas Barnett Shale over the 

past ten years have unleashed an unprecedented new shale gas industry across North America. The most effective completion 

technique is known as hydraulic fracturing (or “fraccing”), a process that involves injecting a large volume (60,000 to 

140,000+ bbls) of fresh water underground to fracture the formation, increasing permeability and thus gas flow. After a frac 

is completed, a large portion of the frac fluid returns to the surface as “flowback” water which contains high concentrations 

of dissolved salts, frac chemicals, and formation minerals. The flowback water is highly variable and its composition is 

affected by factors such as the subsurface geology, the length of time the water has been in contact with the formation and the

chemical composition of the frac water used. The costs and logistics of managing both fresh and flowback water in shale gas 

plays are problematic. Development of North America’s shale gas resources will require well developed water management 

strategies that include the effective implementation of water recycling technologies. Water and the key role it plays in the 

development of non-conventional oil and gas reserves such as shale gas is becoming a very contentious public issue, 

particularly in light of the recent development of the Marcellus Shale in the northeast United States. This is emerging as a 

very important environmental issue for operators and indeed for the entire gas shale industry. By making the recovery of and 

beneficial re-use of a portion of the brackish produced water from these shales efficient and cost-effective, an environmental 

liability can be turned into an asset. 

FLOWBACK OVERVIEW 

Flowback is defined as the return of the fluid to the surface after a completion or frac job. The quality and quantity of the 

flowback is a function of a number of key factors: the quality of the initial source water used to make the frac fluid, the frac 

fluid chemical program, the formation geology, contact of the frac fluid with formation waters, and the time the fluid spends 

both underground and on the surface after the frac. The source water makes up over 99% of the total frac fluid and as a result

impacts the quality of the resulting flowback. Components in the source water such as dissolved salts, minerals, organic 

material and/or bacteria will either return to the surface in the flowback or have the potential to react with the frac or 

formation chemistry. Chemical additives (primarily polyacrilaymide friction reducers in shale gas slick fracs) are another 

key component of flowback. The type and amount of chemical additives varies depending on the specifics of the geology 

and the completion strategy. The chemical additives used during fraccing are designed to remain dissolved in the frac fluid 

under a wide range of conditions and, as a result, return to the surface in the flowback. The formation geology is another key

factor impacting flowback quality. The shale formations are a composite matrix of carbonate shale and salt crystals. During 

the frac operation, the frac fluid comes in contact with the formation geology and dissolves salt and formation minerals, 

returning these to the surface in the flowback. The amount of dissolved material in the flowback is a function of the 

formation geology and the length of time spent underground. The longer the flowback remains in the formation, the more 

contact it has with formation geology and, as a result, the more dissolved solids it will contain. The solubility of the 

formation is also a key factor impacting the amount of dissolved solids in the flowback. If the formation is in communication 

with an aquifer or other subsurface formation waters, the frac fluid will blend with this formation water. Formation waters in

contact with shale gas formations typically have very high levels dissolved solids (>100,000 mg/L). Flowback from 

completions in contact with formation waters is generally higher in levels of dissolved solids and volume. Time is another 

critical factor impacting the quality of flowback. As discussed, the time spent underground increases the level of dissolved 

solids. After the flowback returns to the surface, time is also an issue as bacteria will start to grow resulting in the breakdown 

of organic material and if sulphates are present, can cause the formation of hydrogen sulphide (H2S). 

When the flowback returns to the surface it contains dissolved salts, dissolved minerals, residual frac chemicals, frac 

chemical degradation products, bacteria, suspended solids, normally occurring radioactive material, volatile organics, 

hydrocarbons, and ammonia. The concentration of these materials varies from play to play from well to well within the same 

play and from day to day on the same well. Average flowback compositions from the Fayetteville, Marcellus, and Barnett as 

as follows: 
SPE 147264 3 

Flowback water is challenging to treat due to the high degree of variability, the high fouling potential and the wide range 

and concentration of key components. These fouling mechanisms can be broken down into the following five catagories: 

Suspended Solid Accumulation 

Residual suspended solids that are not removed in the pre-treatment system have the potential to settle at low 

velocity points or deposit on surfaces within the unit. Suspended solids can also precipitate (metal hydroxides, etc.) 

due to increases in temperature and concentration. 

Organic Fouling 

Organic material in the feed water, primarily polymers (friction reducer and residual flocculent) can precipitate 

with an increase in concentration and/or temperature. This material can deposit on surfaces and/or flocculate 

smaller suspended solid particles that wouldn’t otherwise be a problem. 

Carbonate Scale 

The presence of calcium and carbonate in sufficient concentrations can cause CaCO3 scale. The potential for 

CaCO3 scale formation increases as temperature and concentration increase. Carbonate scales are generally white, 

chalky and acid soluble. 

Sulphate Scale 

The presences of sulphate and barium, strontium, and/or calcium in sufficient concentrations can cause BaSO4, 

SrSO4 and/or CaSO4 scale. The potential for sulphate scales to form increase as concentration increases. Sulphate 

scales are generally white, hard or glass like, and acid insoluble. 

Silica Scale / Deposition 

Silica can precipitate out of solution and form solids in one of three ways: surface deposition (depositing directly 

to surfaces), bulk precipitation (colloidal particles collide to form larger particles), complexing (metal hydroxides 

bind with silica to form colloidal particles) and silica polymerization (silica molecules combine to form long 

strings). As silica fouling is greatly impacted by metal hydroxide precipitation, it’s potential increases with 

temperature, concentration, and is highly impacted by pH. Silica deposits can range from quartz-like hard scale to 

slimly deposits (generally white, grey, green or brown - the colour can vary depending on the type of metal 

hydroxides involved). Silica deposits are generally partially soluble in either high or low pH solutions. 

WATER MANAGEMENT DECISION FACTORS 

 An effective shale gas water management strategy is a balancing act between several key factors. Public safety is of 

paramount importance. There is no evidence to suggest that shale gas fraccing poses a risk to drinking or surface water 

contamination (assuming the well is properly constructed and cased), yet management of shale gas flowback on the surface 
4 SPE 147264 

does present handling risks including spillage, potential vehicle accidents and the possible release of flowback into surface 

water as the result. More fatal work injuries result from transportation incidents than from any other event. Highway 

incidents alone accounted for almost one out of every four fatal work injuries in 2008 (U.S. Bureau of Labor Statistics, U.S. 

Department of Labor, 2010). Reducing the truck traffic associated with water hauling is the most effective way to reduce the 

risk of both accidents and the release of flowback to the environment. Water hauling truck traffic is also one of the greatest

impacts to communities affected by shale gas development. The high level of truck traffic causes damage to existing road 

infrastructure (often not designed for heavy hauling), and can create high levels of traffic conjestion, pollution and dust. 

High truck traffic is often one of the greatest concerns for local communities and strategies that minimize traffic often 

improve the willingness of land owners and communities to cooperate with producers. The regulatory environment also 

influences how the overall water management strategy is put together. Regulations often dictate how much water can be 

stored on the surface, the type of containment needed for storage, the types of pipelines allowed (either temporary or 

permanent), and the rules around discharge and disposal. Environmental liability is another key concern. Spill related 

incidents related to the transportation and storage of flowback can be exteremly costly. Spill risk management is an 

important factor to take into consideration. Reducing the risk of flowback spills is a critical risk management objective. 

Clean-up of salt water spills, specifically in environmentally sensitive areas or near watersheds can be expensive. A 

management plan that reduces the potential for spills and releases will go a long way to reducing long term costs. Shared 

long term access to source water and disposal is also critical. Water and disposal sources often have sufficient supply in the

early stages of field development but this demand increases as activity increases, and the collective water demand can often 

exceed the supply. Producers need to look at long term overall supply with respect to the collective demand of all water 

users in the area, including other producers, other industries, agriculture, and municipal water supplies. Water supply issues

can become increasing complex in areas where competition for water sources is already high such as in arid climates, urban 

areas, or regions that require large volumes of water for industrial or agricultural use. Industrial or municipal waste water 

sources can often be used as source water for frac fluid with minimal treatment and facilities accepting flowback can be 

designed to accept other industrial waste which can reduce overall treatment costs and create more make-up water for re-use. 

The quality of water used to develop the frac fluid and how this impacts well production is a critical factor in developing 

a water management strategy. Multivalent ions (Fe, Ca, Mg, Ba, Sr) and chlorides in the water can limit friction reducer 

effectiveness and drive up horsepower costs for the producer’s frac pumping operation. The type and dose of friction reducer 

can be adjusted to accommodate for higher TDS water but at an added cost. Scaling tendency of the source water and/or poor 

compatability of source water with formation water, and/or poor compatability of re-use water with make-up water can result 

in scaling. The scaling can occur within the formation creating the potential for reduce permeability and ultimately reduced 

gas production. Scaling can also occur in equipment casing which can damage equipment or reduce the equipment 

functionality. Bacteria in the frac fluid can cause formation biofouling, reducing permeability and gas production. The 

presence of sulphate reducing bacteria (SBR) can form hydrogen sulphide (H2S), making the well sour, creating safety issues 

and increasing overall costs. Metals in the water, specifically iron, can oxidize and form deposits, reducing permeability and

gas production. Suspended solids in the frac fluid such as sand, silt, clays, and scale particles can lead to reduced 

permeability and gas production. As shale gas formations are a composite of carbonate shales and salt crystals, the use of 

low TDS frac fluid will increase dissolution of formation salts, potentially increasing reservoir permability and gas 

production. A qualitative understanding of the relationship between frac fluid water quality and long term well production is 

key to the cost / benefit analysis of the level of water treatment technologies encorporated into the water management plan. 

TREATMENT OPTIONS 

Flowback management strategies can be broken down into three key types: disposal, re-use and recycling. In disposal 

scenarios, fresh water is transported to site from available sources and flowback is transported to an injection well for 

disposal. The disposal scenario is often chosen if there is an inexpensive, abundant supply of fresh water nearby and nearby 

injection wells are able to handle the flowback disposal volumes. As fresh water availability decreases, costs increase and/or

distance to injection wells for disposal increases, the disposal scenario becomes less appealing. Re-use strategies involve 

primary treatment of the flowback to remove suspended solids and soluble organics and then blending the treated water with 

fresh water to generate the frac fluid for a new well. Re-use strategies reduce the amount of fresh water required and can 

eliminate the need for disposal provided all of the flowback can be treated and re-used. Re-use is often the least expensive 

strategy, especially in areas with high disposal costs. Recycling strategies involve high level treatment of the flowback water 

producing a fresh water quality product. The recycled water is blended with make-up water from freshwater sources to 

generate a low TDS flac fluid. Recycling is used when fresh water costs are high or a high quality, low TDS frac fluid is 

desired or when other logistics (such as fraccing schedules) do not permit re-use strategies. Producers that transfer the frac

fluid via temporary above ground pipelines (known as “fastlines”) may choose the recycling option to minimize the potential 

environmental liability from a spill or fastline rupture. 
SPE 147264 5 

The level of treatment required can vary depending on the quality of water required for frac fluid. Available levels of 

treatment as as follows: REUSE TREATMENT 

LEVEL 0 – No treatment, direct blending of flowback with make-up 

water. 

TSS – No Change 

TDS – No Change 

100% available for re-use 

LEVEL I – Basic TSS Removal. TSS - < 25 mg/L 

TDS – No Change 

100% available for re-use 

LEVEL II – Low Polish, basic TSS removal followed by media 

filtration. 

TSS – Filtered to 5 um 

TDS – No Change 

100% available for re-use 

LEVEL III – High Polish, basic TSS removal followed by membrane 

filtration. 

TSS – Filtered to < 1 um 

TDS – No Change 

100% available for re-use 

LEVEL IV – Selective Ion Removal, basic TSS removal followed by 

membrane filtration and ion exchange or nanofiltration. 

TSS – Filtered to < 1 um 

TDS – Divalent ions removed as required 

100% available for re-use 

RECYCLE TREATMENT 

LEVEL V – Distillation, basic TSS removal followed by MVR 

Evaporator (TDS removal). 

TSS - < 10 mg/L 

TDS < 100 mg/L 

60 to 90% Available for re-use 

LEVEL VI – Crystallization, basic TSS removal followed by MVR 

Evaporator and crystallizer (TDS removal) or direct fired evaporator. 

TSS - < 10 mg/L 

TDS < 100 mg/L 

100% available for re-use 

TSS – Total Suspended Solids TDS – Total Dissolved Solids 

RE-USE TECHNOLOGY 

During an active hydraulic fracturing program, natural gas producers are faced with inconsistent flowback water 

containing total suspended solids (TSS) ranging from 100 to 3,000 ppm and total dissolved solids (TDS or Salts) ranging 

from 5,000 to 100,000 ppm. Recent legislation enacted in Pennsylvania, heart of the Marcellus play, requires a maximum 

TSS of 250 ppm with a maximum combined TSS/TDS of 500 ppm to obtain a new or expanded discharge permit for treated 

flowback. Aqua-Pure piloted and tested 12 individual technologies in the development of a robust and adaptable clarifier 

applicable to the wide spectrum of oilfield conditions. The re-use technology in Aqua-Pure’s ROVER Mobile Clarifier has 
6 SPE 147264 

been in continuous and successful operation for 6+ years with a major gas producer. The re-packaging of this technology has 

enabled a mobile unit aligning with the natural portability of oilfield services. Aqua-Pure’s ROVER Mobile Clarifier consists 

of a low profile, clarification trailer and auxiliary support trailer. Flowback is pumped from the customers’ source (frac tank, 

pit, etc.) into the unit via an adaptable location feed pump. Suspended solids and organics are precipitated from the solution

using an adjustable chemical system. The solids settle to the bottom where they are collected and de-watered. Clean brine is 

pumped out of the system to a designated location specified by the customer. This mobile clarifier allows producers to 

recycle water on-demand, providing a powerful and flexible tool in managing oilfield operations. Capacity is 10,000 bbl/day 

of feed water. The unit is DOT approved for non-permitted transportation in the United States and Canada. Deployment of 

ROVER Mobile Clarification technology has many benefits for the industry. The direct costs associated with water 

transportation are significant and well documented. The social cost of water transportation, heavy truck traffic in often rural 

and small towns with limited road networks is an ongoing legal, public relations and insurance risk. Allowing water to be 

treated and recycled at or very near the wellhead reduces this impact by reducing water transportation needs. Availability, 

cost and the complex logitics of acquiring fresh water must be considered in the financial analysis of mobile clarification 

technology. Migration of the treatment process near the wellhead is quickly becoming an industry best practice and aligns 

closely with the risk management policies of many stakeholders. 

Figure 1. Aqua-Pure ROVER Mobile Clarifier 

RECYCLING TECHNOLOGY 

Recycling technologies for flowback generally include two main categories: (1) membrane-based systems, and (2) 

thermal (evaporator) systems. Membrane technologies have generally proven ineffective in shale gas flowback recycling to 
SPE 147264 7 

date and are not discussed in detail in this paper. Membrane systems are most effective when treating water with consistent 

levels of specific contaminants. Variations in the type and concentrations of contaminants will cause these systems to fail, 

requiring frequent cleaning or recalibration. Increasing the energy efficiency of thermal evaporator systems reduces operating 

costs and carbon emissions. Increasing the utilization factor allows for better use of all associated resources, ensuring that the 

maximum volume of water is recycled for fixed capital and operating costs. This reduces costs on a per volume basis so that 

recycling operations are economically sustainable and able to grow to meet market demand. In 2003 Fountain Quail made 

contact with shale gas producers in the Texas Barnett field and began a search for solutions to managing shale gas water. 

Aqua-Pure Ventures (“Aqua-Pure”) from Calgary (Canada) worked with Texas-based Fountain Quail Water Management 

(“Fountain Quail”) to design the NOMAD 2000 - a mobile, modular version of Aqua-Pure’s process patented Mechanical 

Vapor Recompression (“MVR”) evaporation technology, specifically for operation in shale gas fields. The Aqua-Pure MVR 

technology was already in use for heavy oil applications at that time, and the NOMAD 2000 design built on Aqua-Pure’s 

experience in handling oilfield produced water. Aqua-Pure eventually acquired Fountain Quail and established it as a service 

company based in Texas that owns and operates the equipment and charges producers for the water processed on a per 

volume basis. For the past seven years Fountain Quail has owned and operated its own equipment and used it in aggressive, 

high fouling water recycling applications. Fountain Quail monitored the performance and problems with the equipment 

designs and has made a series of design changes that have led to step improvements in both system efficiency and reliability. 

A high level of in-house knowledge has been accumulated on corrosion, metallurgy, scaling and fouling, water chemistry, 

process optimization, and innovative construction techniques. The NOMAD 2000 MVR Evaporator is a highly energy 

efficient process for producing distilled water from wastewaters contaminated with dissolved salts. Evaporative treatment 

involves boiling a solution such that contaminants remain in the liquid phase, while pure water vapor evaporates and can be 

condensed into distilled water. MVR evaporation differs from conventional evaporation in that a compressor is used to input 

the energy required to generate steam rather than a heat source such as a boiler. The high energy efficiency is achieved by 

utilizing the latent heat of the condensing steam as the primary energy source for boiling the wastewater. Conventional 

distillation requires 1,000 BTU/lb of steam, while MVR evaporation requires a theoretical 25 BTU/lb of steam produced. The 

energy input by the compressor for MVR evaporation is required to compensate for the difference in latent heat of 

vaporization between the boiling brine and condensing steam, heat losses in the pre-heat exchangers, and energy loss of the 

system to the environment. The NOMAD produces steam for approximately 50 to 75 BTU/lb (shaft input at the compressor). 

The NOMAD is designed to remove soluble dissolved salts from wastewater at the lowest possible energy cost while at the 

same time allowing for ease of cleaning and serviceability. Insoluble or sparingly soluble material such as oil, suspended 

solids, or mineral compounds suspected of forming high quantities of scale (that cannot be managed with inhibitors) must be 

removed prior to treatment with the NOMAD or fouling can occur, which reduces both the capacity and recovery efficiency 

of the unit. 

A primary innovation of the Aqua-Pure technology involves circulating concentrate through the evaporator side of the 

evaporator exchanger. This circulating concentrate will contain a precisely controlled vapor fraction from 1% to 50%. With 

this controlled low vapor fraction, the concentrated fluid within the evaporator exchanger is subjected to an additional 

localized concentration factor of less than 1.1, avoiding localized precipitation of scaling compounds. As the vapor fraction 

increases while passing through the evaporator exchanger, the steam velocities increase significantly, reducing the risk of 

fouling. The temperature rise of the evaporating side of the evaporator exchanger is kept very low, resulting in low energy for

compression. By adjusting the heat flux, the temperature of the wet surfaces for condensing and evaporating are maintained 

near that of the saturated steam condition. The type of boiling experienced will range from primarily forced convection to 

stable nucleate boiling of the wetted surfaces. 

A secondary innovation of Aqua-Pure technology involves the use of a highly efficient specialized plate and frame heat 

exchanger. The plate type exchanger used offers a low, fixed static head and very low pressure drop on the concentrate 

circulating fluid or evaporating side, while providing a relatively high heat transfer coefficient. The heat flux can be easily

adjusted by adding more surface area or plates in a given frame. The highly effective heat transfer coefficient allows the 

surface temperature to be very near to both fluid stream temperatures, reducing the risk of fouling. There are no hot or cold 

spots and no dead flow zones, which subsequently reduces the risk of fouling or scaling. The compact size can be provided 

cost effectively with exotic alloy plates (i.e. titanium) to resist fluid corrosion and stress corrosion cracking, common to 

desalination type evaporator applications. The compact size also allows for modular construction, reducing both overall size 

and capital cost. 

The NOMAD system has the ability to process highly variable oilfield wastewater and return to the producer 

approximately 85% of the feed volume as distilled freshwater that can be re-used (Barnett Shale example). The NOMAD 

evaporator system is truly revolutionary. It is a system capable of addressing one of the greatest challenges of economically 

treating contaminated water that is the challenge posed by the variable nature and concentration of oilfield wastewater 

contaminants. In order to control the level of dissolved solids in the concentrated boiling fluid, a constant stream is drawn off. 

This is called concentrate. All of the dissolved solid contaminants that enter the system in the Feed water leave the system in
8 SPE 147264 

the concentrate. For example, a Feedwater stream consisting of dissolved solids (Sodium Chloride (NaCl) Salt) will produce 

a distilled water stream and a stream of concentrated Sodium Chloride. 

Figure 2. MVR Evaporator Process Flow 

The Feedwater enters the NOMAD, breaks into two streams and flows through the Pre-Heat Exchangers. One Feedwater 

stream cross exchanges with the Distilled Water leaving the system and the other with the Concentrate leaving the system. 

Both the Distilled Water and Concentrate streams are very hot (near boiling) and transfer heat to the incoming Feedwater. 

The two hot Feedwater streams re-combine and pass through a De-Aerator. In the De-Aerator, dissolved gases (such as 

Carbon Dioxide) in the Feedwater are released and vented. The hot de-aerated Feedwater then enters the Recirculation Loop. 

The Recirculation Loop consists of boiling Concentrate flowing from the Separator to the Circulation Pump to the 

Evaporator Exchange and back to the Separator. The Circulation Pumps transfer the hot Concentrate from the Separator up 

through the Evaporator Exchange. In the Evaporator Exchanger, a portion of the hot Concentrate is boiled into steam. A 

mixture of Steam and boiling Concentrate exits the top of the Evaporator Exchanger and flows into the Separator. Inside the 

Separator the Steam is separated from the boiling Concentrate. The Steam is drawn from the Separator with the Compressor. 

The Compressor boosts the pressure of the Steam and this causes the temperature of the Steam to go up. The high 

temperature, high pressure Steam is driven down through the Evaporator Exchanger. As the high temperature, high pressure 

Steam condenses into Distilled Water, it passes heat to the boiling Concentrate making it boil into Steam. 

Hot Distilled Water flows from the bottom to the Evaporator Exchanger into the Distillate Receiver. The hot Distilled 

Water is pumped from the Distillate Receiver through the Feed/Distillate Pre-Heat Exchanger where it cools down, passing 

heat to the incoming Feedwater. The cool Distillate Water then exits the system and flows to the Distillate Pit. To prevent the

Salt concentration from getting too high in the Recirculation Loop, a constant stream of boiling Concentrate is drawn from 

the Separator with the Concentrate Pump. The boiling Concentrate is pumped through the Feed/Concentrate Pre-Heat 

Exchanger where it cools down, passing heat to the incoming Feedwater. The cool Concentrate then exits the system and 

flows into the Concentrate storage tanks. Boiling water on the stove requires 1,000 BTU of energy to product 1 pound of 

Steam. MVR Evaporation uses a theoretical 50 BTU of energy to produce 1 pound of steam (5% of the energy of 

conventional evaporation). 

The key to the success for the technology requires that the cost of treatment has to be less than the cost of disposal to 

make the technology viable. The success of the NOMAD technology is based on patented evaporator design allowing the unit 

to be portable, self sustaining and treating the water to allow reuse and recycle. Fountain Quail (Aqua-Pure) MVR 

Evaporators remain one of the only technologies operating in shale gas flowback recycling applications due to their high 

recovery efficiency and resistance to scaling and fouling. To date over 14,000,000 barrels of hydraulic fracturing flowack and 

produced waters have been recycled for re-use in the Barnett Shale. As other shale gas plays are being developed, Fountain 

Quail technology is being looked at as a leading example of effective shale gas water management recycling technology. 
SPE 147264 9 

Figure 3. Aqua-Pure NOMAD MVR Evaporator 

CASE STUDIES 

FOUNTAIN QUAIL BARNETT SHALE RECYCLING FACILITY 

Fountain Quail’s Barnett shale recycling facility consists of a level V treatment system (Pre-Treatment + MVR 

Evaporators). The facility is set-up in an area with high drilling density in the immediate vicinity. The photograph below 

provies a good overview of the recycling logistics. Three well pads surround the recycling facility. Each well pad contains 

four horizontal wells (twelve in total between the three pads). Fresh water is pumped via fast line (aluminum irrigation 

pipeline) from a fresh water pit directly to the frac. After the frac is completed, flowback is returned to the flowback pit at 

the recycling facility via a temporary 3” poly pipeline. The flowback is processed to distilled water quality at the recycling

facility and returned to the fresh water pit to be blended with make-up water for re-use. Locating the recycling facility this

close to the operation drastically reduced the number of trucks required to move in fresh water and haul out wastewater for 

disposal. As transporation is generally the largest cost associated with water management, the proximity of the recycling 

facility helped reduce overall completion costs significantly. Fountain Quail has operated up to four concurrent recycling 

operations in the Barnett Shale with a combined capacity of close to 20,000bbl/d of flowback treatment. 

Figure 4 – Fountain Quail Barnett Shale Recycling Facility with 2 NOMAD evaporators. There are 3 frac operations 

surrounding the facility. 
10 SPE 147264 

EUREKA RESOURCES MARCELLUS SHALE RECYCLING FACILITY 

Eureka Resources Marcellus shale recycling facility consists of a level V treatment system (Pre-Treatment + MVR 

Evaporators). Transporation to disposal is very expensive in the Marcellus shale due to the low availability of disposal wells. 

The Eureka facility is used to treat flowback to distilled water quality and discharge it to a municipal wastewater facility 

(POTW) that blends the distillate with treated municipal waste and discharges it to the river. The facility is located closer to 

the source of drilling than available disposal wells and as a result, reduces flowback transportation costs.

Figure 5 – Eureka Facility (Williamsport, PA) Utilizing Three Aqua-Pure NOMAD Evaporator Systems. 

Aqua-Pure technology and solutions can be customized to meet a wide range applications and capacities. 
29

Appendix B

Graph from Fountain Quail and Aqua Pure on the 

Water Recovery Performance of the 

Mechanical Vapor Recompression System

Brent Halldorson, 2012
40%

50%60%70%80%90%

100%

Distillate Recovery

MVR Evaporator Revovery as a function of Feed Gravity for Oilfie

Theoretical MVR MaximumNOMAD PotentialNOMAD Potential with Compressor Upgrade

0%

10%20%30%

1.000 1.010 1.020 1.030 1.040 1.050 1.060 1.070 1.080 1.090 1.100 1.110 1.120 1.130 1.140 1.150 1.160 1.170 1.180 1.19

Feed Specific Gravity