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TECHNICAL MEMORANDUM

Deskins Greenhouse Gas Comparison Study PREPARED FOR:

F. D. Deskins, Inc.

PREPARED BY:

CH2M HILL

DATE:

March 19, 2010

Introduction Greenhouse Gas (GHG) mitigation and regulation are becoming focal points for many municipalities and utilities across the United States and around the world. Representatives from utilities are now requesting that carbon footprint be added to criteria for alternative evaluation to focus on system sustainability and to receive stimulus funding that has been set aside for “green” projects. Many utilities will have to report their emission inventories annually, and their GHG emissions may be regulated in the future. Therefore, it is important to evaluate the carbon footprint of potential wastewater treatment plant (WWTP) liquid treatment and biosolids processing facilities to address these potential regulatory issues and avoid negative environmental impacts. This technical memorandum (TM) provides a summary of the comparison of the GHG emissions associated with the construction and operation of three commonly used wastewater biosolids dewatering processes: the Deskins filter bed system (new and retrofitted), a belt filter press dewatering system, and a centrifuge dewatering system. Process assumptions, using common thickening and digestion facilities, were made to develop generic 5, 10 and 20 MGD WWTP GHG comparisons of the three selected dewatering system alternatives. Although no two WWTPs are entirely alike and these facilities do not actually exist, this approach provides a common basis for comparison, and the general results from this comparison are applicable to many actual facilities throughout the United States. This approach assuming average and typical design criteria and operating conditions was used for evaluation of the biosolids dewatering systems in order to present the F. D. Deskins, Inc. Company (Deskins Company) with independent and unbiased GHG emission data.

Overall Greenhouse Gas Emissions Accounting Methodology The methodology used to develop readily comparable estimates of GHG emissions from the design criteria for the various wastewater biosolids dewatering systems is largely based on the General Reporting Protocol (v1.0) published by The Climate Registry modified to include significant supply chain GHG emissions and GHG emissions during construction. This methodology is largely consistent with ISO 14040 Life Cycle Assessment and ISO 14064-1 Greenhouse Gases, but is not designed to include those life cycle sources deemed de minimis. Some downstream GHG emissions are neglected, but assumed to be substantially

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equivalent for the alternatives. The methodology is designed to be largely compatible with PAS-2050, Bilan Carbone, and other global standards but not entirely equivalent.

CH2M HILL Parametric Cost Estimating System The CH2M HILL Parametric Cost Estimating System (CPES) is a proprietary tool developed by CH2M HILL staff, capable of producing parametric facility designs. The tool allows users to specify each component, or module, of the facility including treatment technologies, chemicals, electric power, natural gas, and others. Each individual module within CPES has been developed using generic design parameters and materials quantities developed from previous projects. These parameters allow for dimensional accuracy in regards to the building footprint associated with each module. Once the modules have been selected that will compose the proposed facility, the user then enters design criteria specific to the project. These criteria can vary from flow or loading rates to the number and size of the biosolids dewatering equipment. Once all pertinent design criteria have been entered into CPES, material quantities and facility dimensions are calculated. These values provide a summary for all materials, equipment, and construction activities required to produce the proposed facility. The approximate capital cost, if needed, can also be calculated. This allows the user to determine the carbon footprint associated with all construction activities required to produce the completed facility. Another feature of CPES is the life cycle analysis tool. The life cycle module imports data from the parametric facility design and cost estimate to produce a summary of annual costs and resource consumption associated with the operations and maintenance (O&M) of the proposed facility. Resource consumption such as energy, fuel, chemicals, and replacement of consumable materials are calculated and reported on an annual basis within the life cycle tool. This allows the user to quantify the carbon footprint associated with O&M activities at the facility for a full year of operation. The CPES life cycle module differs from ISO 14040 in that it is not a full four phase assessment process. The module only addresses the inventory analysis phase. The tool simply creates an inventory of materials that can be further analyzed according to the four phase assessment. Scope definition, impact assessment, and interpretation are all contained to the greenhouse gas module discussed below. Both the parametric facility design and life cycle analysis modules are linked to the Greenhouse Gas (GHG) Calculation Module, also developed by CH2M HILL staff. The values obtained from the parametric facility design and life cycle modules are directly imported into the GHG module so that all emissions from construction and O&M can be quantified. However, no comparative capital, annual or present worth costs were generated using the CPES for the three biosolids dewatering systems for the three generic WWTPs in accordance with the scope of work of this project.

Documentation and Assumptions Given the complexity and scope of the proposed facilities and alternatives, some assumptions were required in order to develop the facility designs and accountings of GHG emissions. The following section includes a summary and discussion of these assumptions,

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and provides documentation of the emission factors and values used in the emission calculations.

General In order to compare emissions from varying sources, all emissions must be converted into a common unit. The commonly accepted unit is carbon dioxide equivalents, or CO2e, due to the abundance of CO2 in the atmosphere. When looking at the concentrations of GHG in the atmosphere, CO2 is by far the most abundant. Converting gases in smaller quantities to CO2e allows for the simplest calculation of total GHG emissions. These emission factors are applied uniformly within the GHG module. The two factors below in Exhibit 1 are the global warming potentials (GWP) for the non-carbon dioxide (CO2) gases of concern, methane (CH4) and nitrous oxide (N2O). The GWPs are based on the degradation time of each molecule in the atmosphere in comparison to the most prevalent GHG, CO2. By multiplying each gas by its GWP, that gas can then be converted to CO2e.

EXHIBIT 1

Global Warming Potential Gas

Global Warming Potential (GWP)

CO2

1

CH4

21

N2O

310

Source: California Climate Action Registry, General Reporting Protocol, Reporting Entity Wide Greenhouse Gas Emissions, Version 3.0, April 2008

GHG Emissions Categories Direct Direct emissions are GHG sources which the entity directly owns or controls. These emissions are put into four categories: stationary combustion, mobile combustion, processrelated, and fugitive emissions. Direct emissions are commonly referred to as scope 1 emissions by many reporting protocols.

Indirect These emissions are a result of the purchase and consumption of electricity. Although these emissions are outside the organization’s boundary, most reporting protocols require quantification of these emissions in order to provide incentives for energy efficiency and conservation. Indirect emissions from electrical purchase are typically referred to as scope 2 emissions in most reporting protocols.

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Indirect (Optional) Optional indirect emissions are sources in which an organization has significant control or influence, and occur within its boundaries. Most of these GHG emissions result from contracted services for upstream and downstream activities such as product manufacturing, transportation, and disposal. These emissions sources are referred to as optional indirect, or scope 3 emissions, because most reporting protocols do not require organizations to report these emissions as a part of their inventory.

De Minimis De Minimis emissions are considered to be sources that are small or negligible in comparison to the overall inventory of the organization. Typically, most protocols do not require any documentation or supporting data regarding these emissions.

Direct Emissions from Mobile Combustion GHG emissions associated with transportation are a Scope 1, or direct emission. The GHG module also accounts for Scope 3 optional indirect emissions from transportation. This is done by taking into account transportation for outsourced activities such as hauling and delivery of construction materials and chemicals. These emissions are not required in all reporting protocols, but these emissions have a significant impact on the total carbon footprint for the facility and should be calculated whenever possible. All transportation associated with hauling and delivery of materials is assumed to be optional indirect emissions. The only direct emissions accounted for within the module are those associated with on-site construction activities such as excavation and backfill. These emissions are discussed further below. The emission factors for mobile combustion emissions, along with the assumptions for vehicle fuel economy are summarized in Exhibit 2.

EXHIBIT 2

Emission Factors for Mobile Combustion Item

Value

Truck Type

Heavy Duty

Percentage of Highway Driving

55

Percentage of City Driving

45

Highway Fuel Economy (miles/gal)

10

City Fuel Economy (miles/gal)

8

CO2 Emission Factor (lbs/gal)

21.958

CH4 Emission Factor (tons/mile)

5.51X10

-6

N2O Emission Factor (tons/mile)

6.61X10

-6

Source: California Climate Action Registry, General Reporting Protocol, Reporting Entity Wide Greenhouse Gas Emissions, Version 3.0, April 2008

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For the Scope 1 emissions for on-site activities, as well as the Scope 3 emissions related to outsourced activities such as hauling and delivery of materials, assumptions were made for travel distances for each category. These mileage assumptions are kept the same for all scenarios and alternatives evaluated for this study. These assumptions are listed in Exhibit 3.

EXHIBIT 3

Assumptions for Transportation Item

Miles

Chemical Delivery

100

Concrete Delivery

25

Structural Backfill Delivery

50

Haul Distance of Excess Dirt

25

Process Piping Delivery

100

Biosolids Hauling to Landfill/Land Application

25

Note: All distances are one way, not roundtrip. Roundtrip distances are accounted for in the module.

The last source for mobile combustion is diesel consumption related to earthwork activities such as excavation, backfill and the biosolids retrieving tractor usage for the Deskins filter bed process. In order to calculate total diesel consumption to complete all earthwork activities, assumptions were made in regards to the efficiency of these machines in varying types of soil. These assumptions are listed below in Exhibit 4.

EXHIBIT 4

Assumed Efficiency of Earthwork Activities Load Factor

Efficiency

Medium Load Factor (Natural Bed Clay) Deskins Biosolids Retrieving Tractor

25 cy/gal 1.63 gal/hr; 45 HP

Source: Means Productivity Standards for Construction, Third Edition, 1994

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Direct Emissions from Solids Disposal at Landfill or Beneficial Use as Fertilizer/Soil Condition on Agricultural Land GHG emissions associated with disposal of the dewatered biosolids at a landfill were calculated based on volume of the biosolids cake assuming the total cake solids concentration and the biological content of the solids. It was assumed that all dewatered solids would be sent to a landfill site located a one-way distance of 25 miles from the generic WWTP. Offsite GHG emissions from the landfill were included in the total GHG emissions estimate. However, these offsite GHG emissions were negligible compared to the onsite GHG emissions and were considered equal for the three biosolids dewatering alternatives. The offsite GHG emissions would be the same if the biosolids were beneficially land applied as a fertilizer/soil conditioner versus disposed of in a landfill.

Indirect Emissions from Electricity The purchase of electricity, considered scope 2 indirect emissions, must be considered when accounting for the GHG emissions of a facility under most globally-accepted reporting protocols. To determine the total CO2e from the purchase of electricity, CH2M HILL staff uses the Environmental Protection Agency’s (EPA) eGRID data that averages emission factors for twenty-six sub regions across the United States. See Exhibit 5 below for the United States national average emission factors used in this study. It should be noted that eGRID factors are defined for a specific point in time. No adjustments in these factors were made due to a potentially changing mix of power supply fuels over the life cycle of the alternatives. Some standard global protocols call for the analysis of operating and build margins to derive these factors. It was assumed for this analysis the EPA eGRID factors would suffice.

EXHIBIT 5

Emission Factors for Electrical Consumption Emission Factor

Value (lbs/MWh)

CO2

1363.00

CH4

0.0196

N2O

0.0298

Source: Environmental Protection Agency Climate Leaders, Greenhouse Gas Inventory Protocol Core Guidance Module, Indirect Emissions from Purchases/Sales of Electricity and Steam, June 2008.

Optional Indirect Emissions from Chemical Consumption The optional indirect emissions from chemical consumption are considered to be scope 3 emissions. These emissions account for the production of the chemical, primarily polymer for this study, at the manufacturing site, and transportation of the chemical to the facility for DESKINS GHG COMPARISON TM COPYRIGHT 2010 BY CH2M HILL, INC. • COMPANY CONFIDENTIAL

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consumption. These emission factors account for the production of the chemical from existing materials and do not account for emissions associated with obtaining or producing the raw materials required production. As discussed in Exhibit 3 above, a one-way chemical transportation distance of 100 miles was assumed for all chemicals. The emission factors for the production of chemicals associated with these proposed facilities are listed in Exhibit 6.

EXHIBIT 6

Emission Factors for Chemical Production (Polymer) Chemical

Emission Factor (lbs CO2/lb chemical)

Liquid Emulsion Polymer

2.082

Source: Life-cycle Energy and Emissions for Municipal Water and Wastewater Services: Case Studies of Treatment Plants in the U.S., Malavika Tripathi, April 2007.

Design Criteria for Biosolids Dewatering Systems In order to estimate the GHG emissions for each alternative, the facility components specific to each scenario must be specified. Once these assumptions were made, the CPES modules were built. These assumptions address system capacity, equipment selection, and biosolids thickening, storage and stabilization requirements. Three WWTP capacity scenarios – 5, 10 and 20 MGD - were evaluated for each dewatering system. The assumptions for the solids thickening and anaerobic digestion processes that preceded dewatering common to each generic 5, 10 and 20 MGD WWTP were as follows: 1.

Primary and activated sludge liquid stream treatment

2.

A 40:60 ratio of primary to secondary waste activated sludge.

3.

Total combined solids production of 2,000 pounds per million gallons of WWTP capacity

4.

Primary solids thickened in primary clarifiers to 5 percent solids concentration with 80% volatile solids concentration

5.

Secondary waste activated sludge thickened in gravity belt thickeners to 5 percent solids concentration with 75 percent volatile solids concentration

6.

Anaerobic digestion of combined primary and WAS sized for 15 day SRT with 30 minute turnover time for hydraulic mixing and 2.5% feed solids concentration to dewatering

7.

50% volatile solids destruction of combined primary and WAS

8.

A class “B” biosolids product was achieved from the anaerobic digestion process.

8.

One story 37.5 foot by 23 foot building assumed for polymer storage and feeding equipment for Deskins filter beds

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9.

One story building (exact building dimensions included in the following tables) assumed for belt filter press and centrifuge equipment.

A summary of the facility component assumptions for each alternative is shown in the following exhibits.

New Deskins Filter Bed System The design criteria for the new Deskins Filter Bed biosolids dewatering system are shown in Exhibit 7. EXHIBIT 7

New Deskins Filter Bed System - Design Criteria 5 MGD Component

10 MGD

20 MGD

Value

Units

Value

Units

Value

Units

8,610

lbs/d

17,220

lbs/d

34,440

lbs/d

Feed Solids Concentration to Deskins Filter Beds

2.5

%

2.5

%

2.5

%

Deskins Filter Bed Solids Loading Rate

2.0

lbs/sf

2.0

lbs/sf

2.0

lbs/sf

Deskins Filter Bed Length

100

ft

100

ft

100

ft

Deskins Filter Bed Width

80

ft

80

ft

80

ft

Number of Deskins Filter Beds

4

#

8

#

15

#

Solids Capture

99

%

99

%

99

%

Dewatered Biosolids Cake Concentration from Deskins Filter Beds (percent as dry weight basis)

30

%

30

%

30

%

Deskins Filter Bed Drying Cycle Time

7

days

7

days

7

days

1.5

BHP

1.5

BHP

1.5

BHP

Hours of Operation (per week) for retrieving biosolids cake material

8

hr

14

Hr

24

hr

Polymer Consumption

11

lbs/dry ton

11

lbs/dry ton

11

lbs/dry ton

Anaerobically Digested Biosolids to Deskins Filter Beds

Total Electrical Load

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Belt Filter Press The design criteria for the belt filter press (BFP) biosolids dewatering system are shown in Exhibit 8. EXHIBIT 8

Belt Filter Press – Design Criteria 5 MGD

10 MGD

20 MGD

Component

Value

Units

Value

Units

Value

Units

Anaerobically Digested Biosolids to BFPs

8,610

lbs/d

17,220

lbs/d

34,440

lbs/d

Percent Dry Solids to BFP

2.5

%

2.5

%

2.5

%

BFP Solids Loading Rate

600

lbs/hr/m

600

lbs/hr/m

600

lbs/hr/m

BFP Hydraulic Loading Rate

50

gpm/m

50

gpm/m

50

gpm/m

BFP Belt Width

2.0

M

2.0

m

2.0

m

Number of Operating Belt Filter Presses

1

#

1

#

2

#

Dewatering Building Length

78

ft

78

ft

90

ft

Dewatering Building Width

56

ft

56

ft

80

ft

Dewatered Biosolids Cake Concentration from BFP (percent on dry weight basis)

17

%

17

%

17

%

Solids Capture

90

%

90

%

90

%

Total Electrical Load

3.1

BHP

6.3

BHP

7.9

BHP

Hours of Operation (per day)

7

hr

7

hr

14

hr

Polymer Consumption

15

lbs/dry ton

15

lbs/dry ton

15

lbs/dry ton

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Centrifuge The design criteria for the centrifuge biosolids dewatering system are shown in Exhibit 9. EXHIBIT 9

Centrifuge – Design Criteria 5 MGD Component

10 MGD

20 MGD

Value

Units

Value

Units

Value

Units

8,610

lbs/d

17,220

lbs/d

34,440

lbs/d

Percent Dry Solids to Centrifuge

2.5

%

2.5

%

2.5

%

Centrifuge Solids Loading Rate

1435

lbs/hr

1435

lbs/hr

1435

lbs/hr

Centrifuge Hydraulic Loading rate

115

gpm

115

gpm

115

gpm

Centrifuge Power

125

BHP

125

BHP

125

BHP

Number of Operating Centrifuges

1

#

1

#

2

#

Centrifuge Bowl Diameter

20

in

20

in

20

in

Centrifuge Bowl Length

100

In

100

in

100

in

Centrifuge Building Length

77

Ft

77

ft

77

ft

Centrifuge Building Width

77

Ft

77

ft

77

ft

Solids Capture

95

%

95

%

95

%

Dewatered Biosolids Cake Concentration from centrifuge (percent as dry weight basis)

22

%

22

%

22

%

Total Electrical Load

131

BHP

131

BHP

259

BHP

Hours of Operation (per day)

6

Hr

11

hr

11

hr

Polymer Consumption

20

lbs/dry ton

20

lbs/dry ton

20

lbs/dry ton

Anaerobically Digested Biosolids to Centrifuges

Results CH2M HILL staff calculated GHG emissions associated with the construction and operation of three commonly used wastewater biosolids dewatering processes: the Deskins filter bed system (new and retrofit), a belt filter press dewatering system, and a centrifuge dewatering system based on the design criteria and GHG assumptions presented in the previous sections of this memorandum.

Deskins Filter Bed Biosolids Dewatering System The GHG emissions associated with the Deskins filter bed system (new and retrofit) for the three capacity scenarios are shown in Exhibit 10. The average breakdown of GHG emissions for the annual O&M activities for the three capacity scenarios for the new Deskins filter bed system is shown in Exhibit 11.

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The GHG emissions from the construction activities are a one-time event that should not be added to the GHG emissions from the annual O&M activities. Specific to the Deskins process, the majority (average of 47 percent) of the overall annual O&M emissions for each of the three plant capacities are a result of polymer use; while the second highest (average of 20 percent) was from diesel fuel use by truck transport of the biosolids and land application of the biosolids; and the third highest (average of 19 percent) was from power consumption of the biosolids feed pump and polymer system equipment and heat, cool, ventilate and illuminate the polymer storage and feed building.

EXHIBIT 10

Deskins Filter Bed System GHG Summary 5 MGD

10 MGD

20 MGD

Emissions

Emissions

Emissions

Units

Electrical Power

14.52

14.64

14.76

Tons CO2e/yr

Chemicals (Polymer)

18.37

36.49

72.47

Tons CO2e/yr

Biosolids Retriever Tractor Diesel Emissions

5.86

11.71

21.97

Tons CO2e/yr

Offsite GHG Emissions (Solids Transport to and application at Agricultural/ Landfill Site)

12.41

15.37

21.29

Tons CO2e/yr

Total Annual O&M GHG Emissions

51.16

78.21

130.49

Tons CO2e/yr

New

42.75

80.78

145.17

Tons CO2e/yr

Retrofit

9.05

14.00

19.00

Tons CO2e/yr

GHG Category

Construction GHG Emissions

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Exhibit 11 Average Annual O&M GHG Emissions Chart for the Deskins Filter Bed System

Belt Filter Press Biosolids Dewatering System A summary of the GHG emissions associated with the belt filter press biosolids dewatering system is shown in Exhibit 12. The average breakdown of GHG emissions from annual O&M activities for the three capacity scenarios for the BFP system is shown in Exhibit 13. The majority of the overall emissions (66 percent) are attributed to the power required to operate the biosolids feed pump, polymer system, and BFP equipment and heat, cool, ventilate and illuminate the BFP dewatering building; while GHG emissions as a result of polymer use is the second highest at 26 percent. However, as the generic plant size increases in capacity from 10 to 20 MGD, GHG emissions as a result of electrical power generation become a smaller percentage (57 percent) of the overall GHG emissions.

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EXHIBIT 12

Belt Filter Press GHG Summary 5 MGD

10 MGD

20 MGD

Emissions

Emissions

Emissions

Units

Electrical Power

111.76

119.03

163.92

Tons CO2e/yr

Chemicals (Polymer)

25.21

49.64

99.28

Tons CO2e/yr

Offsite GHG Emissions (Solids Transported to and application at Agricultural/Landfill Site)

12.56

15.66

21.86

Tons CO2e/yr

Total Annual O&M GHG Emissions

149.53

184.33

285.06

Tons CO2e/yr

17.9

18.04

23.91

Tons CO2e/yr

GHG Category

Construction Activities

Exhibit 13 Average Annual O&M GHG Emissions Chart for the Belt Filter Press Dewatering System

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Centrifuge Biosolids Dewatering System A summary of the GHG emissions associated with the centrifuge biosolids dewatering system is shown in Exhibit 14. The average breakdown of GHG emissions resulting from annual O&M activities for the three capacity scenarios for the centrifuge system is shown in Exhibit 15. The majority of the overall average emissions (75 percent) are attributed to the power required to operate the equipment (significantly higher for the centrifuge compared to the other two dewatering alternatives) and heat, cool, ventilate and illuminate the centrifuge dewatering building; while GHG emissions as a result of polymer use is the second highest at 20 percent. In fact, the GHG emissions that result from electrical power consumption for the centrifuge alternatives is 2.8 to 5.5 times higher than the GHG emissions associated with polymer use.

EXHIBIT 14

Centrifuge GHG Summary 5 MGD

10 MGD

20 MGD

Emissions

Emissions

Emissions

Units

Electrical Power

185.47

270.39

366.38

Tons CO2e/yr

Chemicals (polymer)

33.45

66.35

132.47

Tons CO2e/yr

Offsite GHG Emissions (Solids Transported to and application at Agricultural/Landfill Site)

12.50

15.55

21.64

Tons CO2e/yr

Total Annual O&M Emissions

231.42

352.29

520.49

Tons CO2e/yr

Construction Activities

40.78

40.78

40.78

Tons CO2e/yr

GHG Category

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Exhibit 15 Average Annual O&M GHG Emissions Chart for the Centrifuge Dewatering System

Comparison of GHG Emissions for Biosolids Dewatering Systems CH2M HILL staff compared the GHG emissions for the three biosolids dewatering systems including Deskins filter beds, belt filter press dewatering and centrifuge dewatering for 5, 10 and 20 MGD WWTPs. The comparison is divided into two sections: 1) GHG emissions from construction activities, and 2) GHG Emissions from annual O & M activities.

GHG Emissions from Construction Activities The GHG emissions that are a result of the one-time construction activities are shown in Exhibit 16. The GHG emissions that are associated with the construction of new Deskins filter beds are equal to or significantly higher than the GHG emissions those are a result of the construction of the BFP and centrifuge dewatering buildings for the three WWTP scenarios. Note that the construction of 4, 8 and 15 Deskins filter beds, each with an area of 80,000 square feet, are required for the 5, 10 and 20 MGD WWTP scenarios, respectively. However, nearly 60 percent of the total Deskins filter bed projects involve the retrofitting of existing drying or evaporation beds rather than the construction of new filter beds. GHG emissions from construction activities resulting from retrofitting existing drying beds to Deskins filter beds are much lower than GHG emissions from construction of new filter beds. A separate estimate of GHG emissions from construction activities related to DESKINS GHG COMPARISON TM COPYRIGHT 2010 BY CH2M HILL, INC. • COMPANY CONFIDENTIAL

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retrofitting of existing drying beds to Deskins filter beds (includes removal of existing media and installation of new media, drainage panels, PVC liner and piping and adding taller concrete walls to side of the filter beds) is also included in Exhibit 16. Note that the GHG emissions from the construction activities resulting from retrofitting of existing drying beds to Deskins filter beds is 4.7 to 7.6 times less than the GHG emissions from construction of similar sized new Deskins filter beds. In addition, the GHG emissions from construction activities resulting from retrofitting of existing drying beds with new Deskins filter beds are the lowest of all the three dewatering alternatives and approximately 1.3 to 4.5 times less when compared to belt filter presses and centrifuges. The one story BFP Dewatering Building dimensions range from approximately 80 foot X 80 foot to 80 foot by 90 foot; while the one story Centrifuge Dewatering Building dimensions are 80 foot X 80 foot for all three scenarios. Also, the GHG emissions that are a result of the construction of the BFP dewatering building are lower the GHG emissions from the construction of the centrifuge dewatering building because the structural requirements (structural excavation, backfill and slab thickness) are less. Exhibit 16 Comparison of GHG Emissions from Construction Activities

GHG Emissions from Annual O&M Activities A summary of the annual O&M emissions for each of the dewatering alternatives is shown in Exhibit 17. This summary includes GHG emissions that result from the following: 1) electrical power consumption, 2) chemical (polymer) use, 3) biosolids retriever tractor diesel fuel use, and 4) diesel fuel use by truck transport of the biosolids and land application of the biosolids. The GHG emissions from the annual O & M activities do not include GHG emissions from one-time construction activities.

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DESKINS GREENHOUSE GAS COMPARISON STUDY

Exhibit 17 shows that the Deskins filter bed dewatering system should produce significantly less GHG emissions as a result of annual O & M activities compared to belt filter press and centrifuge dewatering systems. The Deskins filter bed system should produce 2.2 to 2.9 times less GHG emissions compared to BFP dewatering systems and 4 to 4.5 times less GHG emissions when compared to a centrifuge dewatering system that are a result of annual O & M activities for 5, 10, and 20 MGD WWTPs. Exhibit 17 Comparison of GHG Emissions from Annual O&M Activities

Summary and Conclusions The Deskins filter bed biosolids dewatering system produces less overall annual O & M GHG emissions compared to both a belt filter press system and a centrifuge dewatering system for 5, 10, and 20 MGD WWTPs, based on the reasonably and well accepted generic WWTP solids processing facility design criteria and GHG emission assumptions in this Technical Memorandum. When GHG emissions from annual O&M activities are examined, it is apparent that the Deskins filter bed biosolids dewatering system will be “greener” and have a significantly smaller impact on the environment compared to belt filter press and centrifuge biosolids dewatering systems. This is largely due to the relatively small electrical load (only biosolids feed and polymer feed pumps) required for the Deskins system if the filtrate from the process can be discharged by gravity. The GHG emissions that result from the use of electrical power to operate the equipment and to heat, cool, ventilate and illuminate the dewatering buildings for the belt filter press and the centrifuge alternatives are significant. Only a small building to house polymer storage and feed systems that will use minimal electrical power is required for the Deskins filter bed system.

DESKINS GHG COMPARISON TM COPYRIGHT 2010 BY CH2M HILL, INC. • COMPANY CONFIDENTIAL

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DESKINS GREENHOUSE GAS COMPARISON STUDY

The GHG emissions that are associated with the construction of new Deskins filter beds are significantly higher than the GHG emissions those are a result of the construction of the BFP and centrifuge dewatering buildings for the three WWTP scenarios. However, much lower GHG emissions will result from the construction activities from retrofitting of existing drying beds to Deskins filter beds compared with the GHG emissions that will result from the activities from construction of new Deskins filter beds, belt filter press or centrifuge dewatering facilities. As municipalities attempt to decrease GHG emissions from WWTPs in the near future, it is now important to consider GHG emissions from solids processing facilities. As our study shows, it is beneficial to consider and choose the Deskins filter bed system as a biosolids dewatering system over a belt filter press or a centrifuge biosolids dewatering system if the reduction of GHG emissions is a priority and cost and other criteria are considered approximately equal or less for the Deskins filter bed system.

This effort is not intended to endorse the Deskins Company or any other biosolids dewatering processes and should not be presented on the Deskins Company literature or on the website as such. The Deskins Company is to submit the summary of this study for review and approval by CH2M HILL prior to using it in any Company literature or on the website. This letter report is to be distributed as a complete document.

DESKINS GHG COMPARISON TM COPYRIGHT 2010 BY CH2M HILL, INC. • COMPANY CONFIDENTIAL

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