CONSOL Energy, Inc.

Measuring the Benefit of a State of the Art Water Treatment Facility to the Monongahela Basin

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WATER IMPACT INDEXAPPLIC ATION

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Innovative wastewater treatment is critical to ensuring a future with sufficient and clean water, a robust and secure economy, and an ever-improving quality of life. These goals are only attainable if growth and improvement, and the accompanying strain that they place on limited natural resources, is supported with sustainable practices.

This case study reviews how CONSOL Energy Inc., a leading energy sector company, partnered with Veolia Water, one of the world’s leading water treatment services and technologies companies, to develop a state-of-the-art mine water treatment facility.

The facility integrates chemical precipitation, reverse osmosis and thermal technologies developed by Veolia to maximize the recovery of clean water for return to the environment. A design-build-operate project delivery approach is used that allows CONSOL to focus on its core business while ensuring facility performance to the highest standards. The result is an enhancement of water resources in the Monongahela River basin in Northern West Virginia, which is the exact intent of sustainability, to protect the environment while supporting economic and quality of life needs.

To provide an accurate measure of the benefit provided by the facility, the Water Impact Index was applied. The Water Impact Index is a comprehensive water footprint indicator developed by Veolia Water. It integrates all the aspects of the water cycle, including water quality, water availability in the local environment, and volume to provide an accurate measure of environmental benefit.

This case study describes several elements of CONSOL’s mine water treatment project, including the treatment process, an introduction to the Water Impact Index, and the approach used to measure the benefit that treatment delivers to the Monongahela River basin.

Project DescriptionCONSOL’s mine water treatment facility is located near Mannington, West Virginia, and will treat mine water from its Blacksville #2, Loveridge, and Robinson Run mines. Total design capacity is 3,500 gallons per minute (gpm) for a centralized facility. The system applies chemical precipitation, reverse osmosis and thermal technologies that include:• pretreatment with softening and precipitation

chemistry • clarification and filtration polishing • sludge dewatering• reverse osmosis (RO) and return of the purified

permeate stream to the river basin • pretreatment of the RO reject with softening and

precipitation chemistry • evaporation of the softened stream and return of the distillate to the river basin• crystallization of the brine stream• crystallizer solids dewatering

This combination of technologies results in zero liquid waste as well as solids residuals that are safe for landfill, as shown in the block flow diagram below. More importantly, it improves effluent quality such that it not only meets the regulatory requirements, but leads to overall improvement of the local water resource as will be described below.

“ Partnering with Veolia on this project provides CONSOL with a turnkey system coupled with proven operator capabilities” – Katharine A. Fredricksen

CONSOL ENERGY

Introduction

CONSOL’s mine watertreatment facility nearMannington, West Virginia

Raw Water

FeedTank

MultimediaFilter

Aeration

Crystallization Tank

Clarifier

AL Precipitation

R.O. FeedTank

Sludge HoldingTank

Dewatering Equipment

Solids

R.O.

EvaporatorFeed Tank

Crystallization Tank

Clarifier

Evaporator

CrystalizerFeed Tank

CrystalizerSolids DewateringEquipment

Product Water

FinalEffluent

Tank

Technological innovation is not the only special aspect of this project. Cutting edge thinking also underscored CONSOL’s approach to project execution. After reviewing many options CONSOL selected a design build operate (DBO) project delivery approach. The approach provides a complete scope of services and maintains long term responsibility for performance through a single solutions supplier, in this case Veolia. The cornerstone of DBO project delivery is Veolia’s ability to take full responsibility for design, installation, and performance. DBO services are provided to maintain performance at the design basis, including capacity, effluent quality, availability, design build expense, operations expense, and project schedule. On the performance end, Veolia provides a dedicated management, operations and maintenance staff providing 24/7 coverage, operations, preventive and corrective maintenance, and chemicals and residuals dewatering. Together these commitments are delivered through a performance guarantee that is contractually supported by Veolia for the complete term of the project. CONSOL is protected from any shortcomings in plant performance, which are now the responsibility of Veolia.

Assessing the Effect on the Water Resource: the Water Impact IndexMost water footprint assessments focus on volume, a valid indicator to raise awareness but not necessarily sufficient to represent the impact on a water resource. In this particular case, measuring only water quantity would be misleading in that influent and effluent quantities are nearly equal, as depicted below. The influent volumes are projected to be 3,505 gpm or 1.840 billion gallons per year, and the corresponding effluent volumes are 3,490 gpm or 1.835 billion. This is essentially the same amount of water as CONSOL currently discharges from these mines. Consequently, an assessment based on volume alone does not accurately reflect the benefit to the water resource from this project.

Recognizing that water footprint assessments based on volume alone were no longer adequate, researchers at Veolia embarked on the development of an assessment tool that incorporates multiple variables that are important to the viability of the local water resource. In addition, Veolia wanted to develop an indicator that can

Recognizing that water footprint assessments based on volume alone were no longer adequate, researchers at Veolia embarked on the development of an assessment tool that incorporates multiple variables that are important to the viability of the local water resource. The result of Veolia’s effort is the Water Impact Index.

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The results of a volume-basedmeasurement

Raw Water

FeedTank

MultimediaFilter

Aeration

Crystallization Tank

Clarifier

AL Precipitation

R.O. FeedTank

Sludge HoldingTank

Dewatering Equipment

Solids

R.O.

EvaporatorFeed Tank

Crystallization Tank

Clarifier

Evaporator

CrystalizerFeed Tank

CrystalizerSolids DewateringEquipment

Product Water

FinalEffluent

Tank

Blacksville No. 2

Loveridge

Robinson Run

3505 gpm

Veolia Integrated Solution

Treatment Facility

3490 gpm

Landfill

MonongahelaBasin

Mannington•

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be used to support decision-making and communication, among other uses. The result of Veolia’s effort is the Water Impact Index, a comprehensive water footprint indicator that integrates all aspects of the water cycle, including water quality and availability in the local environment.

With the Water Impact Index, the physical water quantity balance for any product or process is weighted by a quality index and a water stress index, as seen above. The water quality index provides a means of measuring changes in water quality and the value of water treatment. The water stress index accounts for the level of stress on the resource. Together these factors, through the Water Impact Index, provide a means of measuring the full water impact. Indirect impacts from the production chain such as water use from energy, raw materials, chemicals, and waste generation are also incorporated into the balance.

The methodology is elegant in its simplicity. In essence, the Water Impact Index is a mass balance equation that compares the quantity, quality, and stress factor of the withdrawn water to the same parameters of the released water (see below). The equation multiplies the three values of volume, stress index, and quality index in the water volume withdrawn, and then subtracts the product of the same three factors for the water volume released.

There are several key points to realize in the mathematics. First, the quality index is based on a component of concern and the same one is used on both sides of the equation. Cref is a reference concentration for this component. It corresponds to the concentration that should be reached to ensure protection of the local

water resource for its intended uses. C is the actual concentration of the component in the withdrawn or released water. Second, the stress index is a dimensionless value between 0 and 1 that reflects the local scarcity of water. The stress index takes into consideration local water use and availability, seasonal variations in fresh water availability and storage capacity. These values have been mapped for most of the world by Pfister, Zurich in 2009.

The Water Impact Index is expressed in gallons equivalent. This is a mathematical representation of the three parameters and is not a true gallon of water. While this concept can appear abstract at first, it provides an optimal tool for decision making purposes. The lower the Index, the lower the impact to local water resources. A negative value implies that the process benefits local water resources. The Index can also be converted back to actual gallons. Using this information, the user of the tool has an idea of what needs to be addressed to lower the impact.

To provide the user with a better understanding of the tool, the following characteristics of the Water Impact Index are provided.

• An increase in the volume withdrawn increases the Index

• An increase in the volume released decreases the Index

• An increase in the stress index of water withdrawn increases the Index

• An increase in the stress index of water released decreases the Index

The Water Impact Index

Water Impact Index Equation

+VOLUME• Water Quality• Volume of

water used – withdrawn and released

STRESS• The Water Stress

Index• Local condition

of resource

QUALITY• Water quality –

withdrawn and released+

Stress Index Quality Index

Volume Withdrawn Volume Released

WIIX = [Wj x WSIj x minl [1; ]]– [ Rk x WSIk x minl [1; ]] CreflCk,l

CreflCj,l

∑ ∑j k

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• An increase in the quality index of the water withdrawn increases the Index

• An increase in the quality index of the water released decreases the Index

Because the methodology is rooted in life cycle concepts and methodologies, it also takes into account indirect water impacts of any process from “cradle to grave.” Considerations for indirect water impact commonly include chemicals and electricity consumed in the treatment process. The calculation is based on quality and stress indexes in the local area in which the electricity is generated or the chemicals are produced. While calculating the direct water impact is done by utilizing the Water Impact Index equation, it becomes cumbersome to calculate all of the indirect impacts with the same approach. To address this, a database of indirect water impact indexes is used. The calculations can be done for all steps in the life cycle of products and services and combined to determine a very comprehensive and informative value.

Applying the Water Impact Index to the Mine Water Treatment FacilityThe Water Impact Index can now be applied to evaluate the benefit of CONSOL’s mine water treatment facility on the local Monongahela River basin. To begin, the boundary conditions were set to the influent that feeds and the treated effluent that is discharged from the mine water treatment facility as shown on page 3. The boundary limits provide a water withdrawn value of 1.840 billion gallons per year and water released value of 1.835 billion, nearly identical. The analysis uses chloride as the component of concern in both the withdrawn and released streams; chloride is the parameter that drove the design of the treatment facility. The reference concentration used for chloride was 230 milligrams per liter (mg/l) based on a water quality standard published by the state of West Virginia for the protection of aquatic life. Both the withdrawal and release occur in the same locale in regard to stress factor index. Accordingly the same value of 0.0229 was used on both sides of the equation. Finally, for indirect inputs, it was assumed that the majority of the impact is related to the life cycle

of the chemicals and energy used to run the plant. The variables input into the equation for the manufacture and transport of chemicals assumed a West Virginia source. The variables used for electricity generation assumed an overall average for the U.S.

Results of AnalysisExamining the calculation results we first see that for the withdrawal part of the equation the direct index is relatively small at 6.4 million gallons eq/yr., as shown below. This is due to the relatively low quality (high chloride concentration compared to the reference concentration) of the water that is withdrawn.

Calculation Results

Indirect Water Impacts

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

5

10

Water withdrawn Water released Indirect WIIX

MG

eq/

year

-30.8 MG eq/year

6.4

-42

4.8

A new metric for assessing water impacts.

Direct WaterImpact Index

Indirect WaterImpact Index

Chemicals

Energy

Waste

METHODOLOGYA new metric for assessing water impacts.

Direct WaterImpact Index

Indirect WaterImpact Index

Chemicals

Energy

Waste

METHODOLOGY

A new metric for assessing water impacts.

Direct WaterImpact Index

Indirect WaterImpact Index

Chemicals

Energy

Waste

METHODOLOGY

Direct WIIX

Indirect WIIX

Energy Chemicals

A new metric for assessing water impacts.

Direct WaterImpact Index

Indirect WaterImpact Index

Chemicals

Energy

Waste

METHODOLOGY

A new metric for assessing water impacts.

Direct WaterImpact Index

Indirect WaterImpact Index

Chemicals

Energy

Waste

METHODOLOGYA new metric for assessing water impacts.

Direct WaterImpact Index

Indirect WaterImpact Index

Chemicals

Energy

Waste

METHODOLOGY

A new metric for assessing water impacts.

Direct WaterImpact Index

Indirect WaterImpact Index

Chemicals

Energy

Waste

METHODOLOGY

A new metric for assessing water impacts.

Direct WaterImpact Index

Indirect WaterImpact Index

Chemicals

Energy

Waste

METHODOLOGYA new metric for assessing water impacts.

Direct WaterImpact Index

Indirect WaterImpact Index

Chemicals

Energy

Waste

METHODOLOGY

Water withdrawnWater released

Indirect WIIXTotal WIIX

The net impact is -30.8 million gal eq/year,delivering a positive benefit to the environment

The lower the WIIX value, the greater the benefit

to the water resource.

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Note that withdrawing water from the ecosystem always increases the Water Impact index.

The calculation for water released is more telling. Although the volume is nearly unchanged between withdrawal and release, the significant improvement in the quality index dramatically reduces the direct index to -42 million gallons eq/yr. The quality index, or ratio of reference concentration to actual, goes from 0.15 for the influent water quality to a value of 1.0 for the effluent. Note that the quality index is limited to a value of one even if the quality of the water released is better than the quality required (the reference concentration), which is the case here. Since the larger multiple is on the right side of the equation, doing the mass balance subtraction leads to a negative value for the index. Recall that the lower or more negative the Water Impact Index the greater the benefit to the water resource, in this case the Monongahela River basin. Finally the indirect water impact associated with the chemicals and electricity consumed by the treatment facility is 4.8 million gallon eq/yr, which is mostly due to the electricity used. The net Water Impact Index, depicted graphically on page 5, is -30.8 million gallon eq/yr.

What does all of this mean? Recall we noted that the Water Impact Index can be converted to “real” gallons by backing the stress index out of the equation. In doing so the index value of -30.8 million gallon eq/yr translates to a net volume of 1.3 billion gallons of high quality water returned to the Monongahela River basin on an annual basis. By installing this treatment facility, CONSOL is making the water available to support other uses and contributing to an overall improvement in water quality in the basin.

Concluding SummaryIn conclusion, the objective of measuring the benefit of CONSOL’s mine water treatment facility to the Monongahela River basin has been achieved through the use of the Water Impact Index. A simple measure of the volume of water withdrawn and returned to the basin provides little insight into the true benefit that treatment provides. To expand on existing volume-based water measurement tools Veolia developed the Water Impact Index, a comprehensive water footprint indicator that integrates all the aspects of the water cycle, including water quality and availability in the local environment. In addition to volume, the Water Impact Index adds a quality index and local stress index to measure the impact of water withdrawn and released back into the local environment. The Index also takes into account indirect water impacts associated with chemicals and electricity consumed by the treatment facility.

Using this approach, the water withdrawn for treatment has a value of 6.4 million gallon eq/yr in comparison to a value of -42.0 million gallon eq/yr for the water returned. While the volume of water for both streams is roughly the same, the improved quality of the returned water brings more value to the basin than the water that is withdrawn, which is of much lower quality.

The indirect water impact from the use of chemicals and electricity at the treatment facility is 4.8 million gallon eq/yr which provides a net impact of -30.8 million gallon eq/yr and delivers a positive impact to the Monongahela River basin. The water impact can be converted back into “real” gallons by backing out the stress index used in the calculation, which converts the index back to 1.3 billion gallons of high quality water supplied to the Monongahela River basin each year. The result is that CONSOL’s Treatment Facility delivers a positive environmental impact back to the Monongahela River basin.

With over 9,000 employees, CONSOL Energy Inc. (NYSE: CNX) is the leading diversified energy producer headquartered in the Appalachian basin. Named one of America’s most admired companies by Fortune magazine, CONSOL Energy produces both natural gas and high-BTU coal. Together, natural gas and coal fuel two-thirds of the nation’s power.

Veolia Water, the water division of Veolia Environnement, is the world leader in water and wastewater services and technological solutions. Its parent company, Veolia Environnement (NYSE: VE and Paris Euronext: VIE), is the worldwide reference in environmental services. With more than 315,000 employees, Veolia Environnement recorded annual revenues of $38 billion in 2011.

Visit the company’s Web sites at: www.veolianorthamerica.com www.veoliawaterna.com www.veoliawaterstna.com Twitter: @veoliawaterna