User’s Guide for Estimating Methane and Nitrous Oxide Emissions from Wastewater Using the State Inventory Tool January 2023


User's Guide for Estimating
Methane and Nitrous Oxide
Emissions from Wastewater
Using the State Inventory
Tool

January 2023

Prepared by:
ICF

Prepared for:

State Energy and Environment Program,
U.S. Environmental Protection Agency

This section of the User's Guide provides instruction on using the Wastewater module of the
State Inventory Tool (SIT), and describes the methodology used for estimating greenhouse
gas (GHG) emissions from the treatment of wastewater at the state level.

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Module 10 - Wastewater Module

January 2023

Table of Contents

1.1	Getting Started	2

1.2	Module Overview	3

1.2.1	Data Requirements	5

1.2.2	Tool Layout	5

1.3	Methodology	6

1.4	Uncertainty	17

1.5	References	17

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.1

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Module 10 - Wastewater Module

January 2023

1.1 Getting Started

The Wastewater module was developed using Microsoft® Excel 2000. While the module will
operate with older versions of Excel, it functions best with Excel 2000 or later. If you are
using Excel 2007 or later, instructions for opening the module will vary as outlined in the
Excel basics below. Before you use the Wastewater module, make sure your computer
meets the system requirements. In order to install and run the Wastewater module, you
must have:

• IBM-PC compatible computer with the Windows 95 operating system or later;

• Microsoft® Excel 1997 or later, with calculation set to automatic and macros
enabled;

• Hard drive with at least 20MB free; and

• Monitor display setting of 800 x 600 or greater.

Microsoft Excel Settings

Excel 2003 and Earlier: For the SIT modules to function properly, Excel must be set to
automatic calculation. To check this setting, launch Microsoft Excel before opening the
Wastewater module. Go to the Tools menu and select "Options..." Click on the
"Calculations" tab and make sure that the radio button next to "Automatic" is selected, and
then click on "OK" to close the window. The security settings (discussed next) can also be
adjusted at this time.

Excel 2007 and Later: For the SIT modules to function properly, Excel must be set to
automatic calculation. Go to the Formulas ribbon and select "Calculation Options." Make
sure that the box next to the "Automatic" option is checked from the pop-up menu.

Microsoft Excel Security

Excel 2003 and Earlier: Because the SIT employs macros, you must have Excel security
set to medium (recommended) or low (not recommended). To change this setting, launch
Microsoft Excel before opening the Wastewater module. Once in Excel, go to the Tools
menu, click on the Macro sub-menu, and then select "Security" (see Figure 1). The Security
pop-up box will appear. Click on the "Security Level" tab and select medium. When set to
high, macros are automatically disabled; when set to medium, Excel will give you the choice
to enable macros; when set to low, macros are always enabled.

When Excel security is set to medium, users are asked upon opening the module whether to
enable macros. Macros must be enabled in order for the Wastewater module to work. Once
they are enabled, the module will open to the control worksheet. A message box will
appear welcoming the user to the module. Clicking on the "x" in the upper-right-hand
corner of the message box will close it.

Excel 2007 and Later: If Excel's security settings are set at the default level a Security
Warning appears above the formula box in Excel when the Wastewater module is initially
opened. The Security Warning lets the user know that some active content from the
spreadsheet has been disabled, meaning that Excel has prevented the macros in the
spreadsheet from functioning. Because SIT needs macros in order to function properly, the
user must click the "Options" button in the security message and then select, "Enable this

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.2

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Module 10 - Wastewater Module January 2023

content" in the pop-up box. Enabling the macro content for the SIT in this way only enables
macros temporarily in Excel but does not change the macro security settings. Once macros
are enabled, a message box will appear welcoming the user to module. Click on the "x" in
the upper right-hand corner to close the message box.

If the Security Warning does not appear when the module is first opened, it may be
necessary to change the security settings for macros. To change the setting, first exit out of
the Wastewater module and re-launch Microsoft Excel before opening the Wastewater
module. Next, click on the Microsoft Excel icon in the top left of the screen. Scroll to the
bottom of the menu and select the "Excel Options" button to the right of the main menu.
When the Excel Options box appears, select "Trust Center" in left hand menu of the box.
Next, click the gray "Trust Center Settings" button. When the Trust Center options box
appears, click "Macro Settings" in the left-hand menu and select "Disable all macros with
notification." Once the security level has been adjusted, open the Stationary Combustion
module, and enable macros in the manner described in the preceding paragraph.

Viewing and Printing Data and Results

The Wastewater module contains some features to allow users to adjust the screen view
and the appearance of the worksheets when they are printed. Once a module has been
opened, you can adjust the zoom by going to the Module Options Menu, and either typing in
a zoom percentage or selecting one from the drop-down menu. In addition, data may not all
appear on a single screen within each worksheet; if not, you may need to scroll up or down
to view additional information.

You may also adjust the print margins of the worksheets to ensure that desired portions of
the Wastewater module are printed. To do so, go to the File menu, and then select "Print
Preview." Click on "Page Break Preview" and drag the blue lines to the desired positions
(see Figure 2). To print this view, go to the File menu, and click "Print." To return to the
normal view, go to the File menu, click "Print Preview," and then click "Normal View."

Figure 1. Changing Security Settings

Figure 2. Adjusting Print Margins

D Microsoft Excel - Bookl

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1.2 Module Overview

This User's Guide accompanies and explains the Wastewater module of the SIT. The SIT
was originally developed in conjunction with EPA's Emissions Inventory Improvement

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.3

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Module 10 - Wastewater Module

January 2023

Program (EIIP) in order to automate the steps states would need to take in developing their
own emission estimates in a manner that was consistent with prevailing national and state
guidelines. The result was a user-friendly and comprehensive set of eleven modules that
help users estimate greenhouse gas emissions at the state level.

Because most state inventories developed today rely heavily on the SIT, User's Guides have
been developed for each of the SIT modules. These User's Guides contain the most up-to-
date methodologies that are, for the most part, consistent with the Inventory of U.S.
Greenhouse Gas Emissions and Sinks (EPA 2022a). Users can refer to the chapters and
annexes of the U.S. Inventory to obtain additional information not found in the SIT or in the
companion User's Guide.

In 2021, EPA began publishing the results of the Inventory of U.S. Greenhouse Gas
Emissions and Sinks disaggregated by U.S. state (EPA 2022b) to make consistent state-
level GHG data available for all states for use by states, researchers, and the general public.
However, EPA recognizes that there will be differences between the state-level estimates
published by EPA and inventory estimates developed by states using the SIT or other tools.
Inventories compiled by states may differ for several reasons, and differences do not
necessarily mean that one set of estimates is more accurate, or "correct." In some cases,
the Inventory of U.S. Greenhous Gas Emissions and Sinks may be using different
methodologies, activity data, and emission factors, or may have access to the latest facility-
level information through the Greenhouse Gas Reporting Program (GHGRP). In other cases,
because of state laws and regulations, states may have adopted accounting decisions that
differ from those adopted by UNFCCC and IPCC to ensure comparability in national reporting
(e.g., use of different category definitions and emission scopes consistent with state laws
and regulations). Users of state GHG data should take care to review and understand
differences in accounting approaches to ensure that any comparisons of estimates are
equivalent or an apples-to-apples comparison of estimates.

The Wastewater module calculates
methane (CH4) and nitrous oxide
(N2O) emissions from the treatment of
municipal and industrial wastewater.

The module provides default data for
most inputs, however other more
state-specific data may be used if available (see Box 1 for suggestions on where to find
data). If using outside data sources, or for a more thorough understanding of the tool,
please refer to the Methodology section below for data requirements and methodology.

Disposal and treatment of industrial and municipal wastewater often result in CH4 emissions.
Wastewater may be treated using aerobic and/or anaerobic technologies, or if untreated,
may degrade under either aerobic or anaerobic conditions. CH4 is produced when organic
material is treated in anaerobic environment and when untreated wastewater degrades
anaerobically, i.e., in the absence of oxygen.

N2O is emitted from both domestic and industrial wastewater containing nitrogen-rich
organic matter. N2O is produced through the natural processes of nitrification and
denitrification. Nitrification occurs aerobically and converts ammonia into nitrate, whereas
denitrification occurs anaerobically, and converts nitrate to N2O. Human sewage is believed
to constitute a significant portion of the material responsible for N2O emissions from
wastewater (Spector 1997).

Box 1: Wastewater Data Sources

In-state sources, such as state departments of
environmental protection, should be consulted first.
Otherwise, default data provided by the Wastewater
module may be used.

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.4

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Module 10 - Wastewater Module

January 2023

1.2.1 Data Requirements

To calculate greenhouse gas emissions from wastewater, the data listed in Table 1 are
required inputs (again, note that defaults are available for most of these data).

Table 1. Required Data Inputs for the Wastewater Module

Wastewater Sectors

Input Data

Municipal Wastewater: CH4
Emissions

Per capita 5-day biochemical oxygen demand (BOD5) (kg/day)
Fraction of wastewater BOD5 anaerobically digested
Emission factor (Gg CFU/Gg BOD5)

State population

Municipal Wastewater: Direct
N2O Emissions

Factor for non-consumption nitrogen
Fraction of population not on septic

Direct wastewater treatment plant emissions (g N20/person/year)

Municipal Wastewater: N2O
Emissions from Biosolids

Emission factor (kg INhO-N/kg sewage N produced)
Fraction of nitrogen in protein (FracNPR)

Protein content (kg/person/year)

Biosolids used as fertilizer (percentage)

Industrial Wastewater: Fruits
and Vegetables

Wastewater Outflow (m3/metric ton)

WW organic content - chemical oxygen demand (COD) (g/L)
Fraction of COD anaerobically degraded
Emission factor (g ChU/g COD)

Production processed (metric tons)

Industrial Wastewater: Red Meat

Industrial Wastewater: Poultry

Industrial Wastewater: Pulp and
Paper

Wastewater Outflow (m3/metric ton)

WW organic content - chemical oxygen demand (COD) (g/L)
Fraction of COD anaerobically degraded
Emission factor (g ChU/g COD)

Production processed of woodpulp and paper & paperboard
(metric tons)

1.2.2 Tool Layout

Because the methodology for estimating emissions from Wastewater treatment is complex,
it is important to understand the module's overall design. The layout of the Wastewater
module and the purpose of its worksheets are presented in Figure 3.

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.5

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Module 10 - Wastewater Module

January 2023

Figure 3. Flow of Information in the Wastewater Module

Control Worksheet



Individual Sector Worksheets

1. Select Sources to Analyze



4. Municipal Wastewater CH4 Emissions

2. Select a State



"! Enter state population

3. Select emission factors and other variables for/

5. Direct N,0 Emissions from Municipal Wastewater

Municipal Wastewater



J. State population from previous worksheet used

CH4 Emissions



6. Municipal Wastewater N20 Emissions

Direct N20 Emissions



i Enter protein consumption and percentage used as fertilizer

N20 Emissions from Biosolids



7. Industrial Wastewater CH4 - Fruits and Vegetables

Industrial Wastewater



1 Enter the amount of fruits and vegetables produced

Fruits and Vegetables



8. Industrial Wastewater CH4 - Red Meat

Red Meat /



J, Enter the amount of red meat produced

Poultry /



9. Industrial Wastewater CH4 - Poultry

Pulp and Paper /



I Enter the amount of poultry produced

4.-10. Complete Sector Worksheets r



10. Industrial Wastewater CH4 - Pulp and Paper





I Enter the amount of pulp and paper produced

11.	View Summary Data <	

12.	Export Data

	>

Summary Data

J Presented in both table and graphical formats in MMTC02E

Uncertainty

Review information on uncertainty associated with the default data

1.3 Methodology

This section provides a guide to using the Wastewater module of the SIT to estimate
greenhouse gas emissions from municipal and industrial wastewater treatment. The
methods used in this module are taken from the report by the Intergovernmental Panel on
Climate Change (IPCC) entitled IPCC Guidelines for National Greenhouse Gas Inventories
(IPCC 2006) and are presented as used in the Inventory of U.S. Greenhouse Gas Emissions
and Sinks (U.S. EPA 2022a).

There are twelve general steps involved in estimating emissions using the Wastewater
module: (1) select industrial wastewater sources; (2) select a state; (3) select emission
factors and other variables used throughout the module; (4) complete municipal wastewater
worksheet; (5) review direct N2O emissions from municipal wastewater treatment
worksheet; (6) complete municipal wastewater N2O emissions worksheet; (7) complete
industrial wastewater ChU- fruits and vegetables worksheet; (8) complete industrial
wastewater Chk- red meat worksheet; (9) complete industrial wastewater ChU- poultry
worksheet; (10) complete industrial wastewater ChU - pulp and paper worksheet; (11)
review summary information; and (12) export data. The Wastewater module will
automatically calculate emissions after you make choices on the control worksheet and
enter the required data on the individual sector worksheets. The tool provides default data
for most sectors.

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.6

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Module 10 - Wastewater Module

January 2023

Step (1) Select Industrial Wastewater Sources

To begin, select the industrial wastewater sources you would like to analyze in step 1 of the
control worksheet. Check the box to the left of the following industrial wastewater sectors
you would like to analyze: fruits and vegetables, red meat, poultry, and pulp and paper.

Step (2) Select a State

Next, select the state you are interested in evaluating. By selecting a state, the rest of the
tool will automatically reset to reflect the appropriate state default data and assumptions for
use in subsequent steps of the tool. Figure 4 shows an example of the control worksheet.

Figure 4. Example of the Control Worksheet in the Wastewater Module

E State Inventory Tool - Wastewater Module

: Sj gle Edit Module Options

0@fx|

Type a question for help

1 T

1 Store Inventory Tool - Wastewater Module

1. Select those sources you wish to analyze.

CH- from industrial wastewater
^ - Fruits and Vegetables
v - Ret! Meat
v - Poultry
I* - Pulp and Paper

2. Choose a State | Colorado
This is very important- it selects the correct default variables for your state.

3. Select emission factors and other variables used throughout this module:
Municipal Wastewater CHj Emissions

Per capita 5-day Biochemical Oxygen Demand (BOD;) (kg/day)
Fraction of wastewater BOD; anaerobically digested
Emission Factor (Gg CH^/Gg BOD;)

Municipal Wastewater Direct H*0 Emissions

Factor non-consumption nitrogen
Fraction of population not on septic

Direct wastewater treatment plant emissions (g N^O/person/year)

Municipal Wastewater ll*Q Emissions from Biosolids

Emission Factor (kg N^D-NAcg sewage N-produced)
Fraction of nitrogen in protein (Frac*PB)

Industrial Wastewater CHj Emissions - Fruits and Vegetables

| Consult EIIP Guidance |

Select Industrial Sectors

Choose a state

Reset ALL!

Clear / Select
All Defaults

Wastewater Outflow (m3/metric ton) 5.6

VWV Organic Content - Chemical Oxygen Demand (COD) (gfl) 5

n\r:nntml/ Mnniriral WW. TH4 / Mnnirinal WW. H7Q. riirnrt / MunirimI WW. N7Q. effluent / Tnri WW Fruit / Ind WW Maat / Tnrl WW Pnnltrv l<

_2_L

Step (3) Select Emission Factors and Other Variables Used Throughout the
Module

The next part of the control worksheet involves selecting default variables or entering state
specific variables in the yellow cells on the control worksheet, as seen in Figure 4. The
required inputs for each sector are discussed further in following steps. Box 2 explains
terminology used throughout the module. Default factors for all parameters are provided in
the control worksheet and may be selected by clicking the gray "Clear / Select All Defaults"
at the top of the worksheet. These factors are drawn from the Inventory of U.S. Greenhouse
Gas Emissions and Sinks (U.S. EPA 2022a) and are used to estimate emissions from
industrial wastewater. If the user-specific inputs do not match the default data in the
control worksheet (i.e., the default value is overwritten), the text will appear red.

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.7

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Module 10 - Wastewater Module

January 2023

Box 2: Wastewater Terminology

In highly organic wastewater streams, e.g., streams from food processing plants or pulp
and paper plants, the available oxygen in the water is rapidly depleted as the organic
matter decomposes. The organic content (sometimes known as "loading") of these
wastewater streams is expressed in terms of biochemical oxygen demand, or BOD. BOD
represents the amount of oxygen taken up by the organic matter in the wastewater during
decomposition. Alternatively, the chemical oxygen demand (COD) is often used to
characterize industrial wastewater. COD refers to the amount of oxygen consumed during
the oxidation of both organic matter and oxidizable /'^organic matter. Under the same
conditions, wastewater with a higher BOD or COD will produce more CH4 than wastewater
with a lower BOD/COD.

Cm from Municipal Wastewater

In the yellow cells for this sector on the control worksheet, enter total biochemical oxygen
demand (BODs)1 produced, the fraction of wastewater BODs anaerobically digested, and the
CH4 emission factor for municipal wastewater emissions.

Direct N2O from Municipal Wastewater

In the yellow cells for this sector on the control worksheet, enter the factor for non-
consumption nitrogen2, the fraction of your state population not on septic systems, and the
direct wastewater treatment plant emissions per person per year.

N2O from Biosolids

In the yellow cells for this sector on the control worksheet, enter the N2O emission factor for
biosolids (the solid potion of human sewage) and the fraction of nitrogen in protein
(FRACnpr).

Industrial Wastewater: Fruits and Vegetables, Red Meat, Poultry, and Pulp
and Paper

In the yellow cells for these sectors on the control worksheet, enter the wastewater outflow
of the particular industrial facility, the organic content of the wastewater, the fraction of
COD anaerobically degraded, and the ChU emission factor.

Step (4) Complete Municipal Wastewater Worksheet

Click on the gray navigational arrow in step 4 of the control worksheet to complete sector
worksheets and continue to the ChU from Municipal Wastewater worksheet. On this
worksheet, the annual state population is entered into the blue cells as seen in Figure 5.
Default data from U.S. Census (2021) is provided, if the "Select Default Data" button is
selected.

1 BOD represents the amount of oxygen that would be required to completely consume the organic
matter contained in the wastewater through aerobic decomposition processes (U.S. EPA 2022). A
standardized measurement of BOD is the "5-day test" denoted as BOD5.

2 This factor represents the nitrogen loading occurring from wastewater going directly into the waste
stream from residences (i.e. bathwater, laundry, and use of garbage disposals) as well as industrial
wastewater that is not included in the four industries analyzed in this module.

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.8

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Module 10 - Wastewater Module

January 2023

Figure 5. Example of the Municipal Wastewater ChU Emissions Worksheet

M N 0 P Q R~

E State Inventory Tool - Wastewater Module

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Type a question for help » _ 0 X |

u |VI w |>>

Al E I C |D| E |F| G |H| I Ul K HI

4. Colorado Municipal Wastewater Methane Emissions

1990

1991

1992

1993

1994

1995
199<

1997

1998

1999

2000

2001

2002

To calculate methane emissions from municipal wastewater treatment, the total annual BODs
production in metric tons is multiplied by the fraction that is treated anaerobically and by the
CHt produced per metric ton of BODSl converted to million metric tons carbon equivalent
(MMTCE), and converted to million metric tons carbon dioxide equivalent (MMTCO^). The
methodology and factors used for these calculations are discussed in detail in the
Wastewater Chapter of the User's Guide.

Continue to the
Next Sheet

>

i Select Default Data ;

State	Pei Capita	Unit

Population	BODi	Dags per Year Conversion

	(kgfday)	[days]	(metric tonsfkg)

VV BOD,
anaerobicallj
Emission Factor	digested	Emissions

(Gg ChVGg BODj)	(percent) (metric tons CH<|





Enter Population
Data





0.60

16.25%

10,551.5

Select Default
Data

Emissions

(MMTCE)

~|=|	0.060

X|	0.27	|=|	0.062

X |	0.27	| = |	0.063

x |	0.27	| = |	0.065

x |	0.27	|= |	0.067

X |	0.27	| = |	0.069

X |	0.27	| = |	0.070

x |	0.27	| = |	0.071

x |	0.27	| = [	0.073

x |	0.27	| = [	0.074

x |	0.27	| = [	0.079

x |	0.27	| = [	0.081

x |	0.27	| = [	0.083

~i \ Control \Municipal WW, CH4/ Municipal WW, N20, direct / Municipal WW, N20, effluent / Ind WW Fruit / Ind WW Meat / Ind WW Poultry |<

The ChU emissions from municipal wastewater treatment are calculated by multiplying the
state population by the total annual BODs production in metric tons, by the fraction that is
treated anaerobically, and by the Chk produced per metric ton of BODs (i.e. the emission
factor); the total is then converted to million metric tons carbon dioxide equivalent
(MMTCO2E). This calculation is shown in Equation 1.

Equation 1. CH4 Emissions from Municipal Wastewater Treatment

CH4 Emissions (MMTCO2E) =

State Population x BODs Production (kg/day) x 365 days/year x
0.001 (metric ton/kg) x Fraction Treated Anaerobically x Emission Factor (Gg
ChU/Gg BODs) x 10"6 (MMT/metric ton) x 25 (GWP)

Click on the gray navigational arrow to estimate direct N2O emissions from municipal
wastewater treatment.

Step (5) Review Direct N2O Emissions from Municipal Wastewater Treatment
Worksheet

There is no required data for this worksheet because the annual state population was
entered in Step (4). Direct N2O emissions from municipal wastewater treatment are
calculated by multiplying total population served, by the fraction of the population not using

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.9

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Module 10 - Wastewater Module

January 2023

septic systems, by an N2O emission factor per person per year, and then converting to
MMTCO2E as seen in Equation 2.

Equation 2. Direct N2O Emissions from Municipal Wastewater Treatment

Direct N2O Emissions (MMTCO2E) =

State Population x Fraction of Population not on Septic (%) x
Emission Factor (g N20/person/year) x 10"6 (metric ton/g) x
10"6 (MMT/metric ton) x 298 (GWP)

Click on the gray navigational arrow to estimate direct N2O emissions from biosolids in
municipal wastewater treatment.

Step (6) Complete Municipal Wastewater N2O Emissions Worksheet

Municipal wastewater N2O emissions from biosolids are calculated by multiplying the state
population by the total annual protein consumption, by the nitrogen content of protein and
fraction of nitrogen not consumed, and by an N2O emission factor per metric ton of nitrogen
treated, then subtracting direct emissions as well as the percentage of biosolids used as
fertilizer, and finally converting to MMTCO2E. Direct and biosolids N2O emissions are then
added to produce an estimate of total municipal wastewater treatment N2O emissions. This
calculation is shown below in Equation 3. Data on annual per capita protein consumption for
the United States have been published by the United States EPA in Table 7-34 of the
Inventory of U.S. Greenhouse Gas Emissions and Sinks (U.S. EPA 2022a).

Equation 3. N2O Emissions from Biosolids Municipal Wastewater Treatment

N2O Emissions (MMTCO2E) =

[State Population x Protein Consumption (kg/person/year) x
FRACnpr (kg N/kg protein) x Fraction of Nitrogen not Consumed
0.001 (metric ton/kg) - Direct N Emissions (metric tons)] x
[1 - Percentage of Biosolids used as Fertilizer (%)] x
Emission Factor (kg N20-N/kg sewage N produced) x
44/28 (kg N2O /kg N) x 10"6 (MMT/metric ton) x 298 (GWP) +

Direct N2O Emissions

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.10

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Module 10 - Wastewater Module

January 2023

Figure 6. Example of the Municipal Wastewater N2O Emissions Worksheet

E State Inventory Tool - Wastewater Module

0HBI

| i Sj File Edit Module Options

Type a question for help » _ 0 X |

A B	C D E F G H I J K L M N 0 P Q R S

6 Colorado Municipal Wastewater Nitrous Oxide Emissions (formerly Human Sewage)

T

Continue
Next Sheet

Select Default Data

to the\.
fleet

F

State Population Protein	Ftacarl

(kg/ person/ (kg W/kg
	year]	protein)

Fiaction Non-
Consumption

Diiect N
N in	Emissions from

Unit	Domestic	Domestic	Diosolids

Conversion Wastewater	Wastewater	Available N

(metric tons/kg) (metric tons)	(metric tons)	(metric tons)

Percentage
of Biosolids

Fertilizer	Emission Facta

(kg NjO-N/ kg sewa
	M-produced)

1**0
1**1
1**2
1**3
1**4
1**5
1**«
1**7
1**8
1***

2000

~ H\

Enter Percentage of Biosolids
Used as Fertilizer

4.327.409
Control / Municipal

41.94 Ix
WW, CH4 /

1.751 x | 0.001 |=| 44,581 |-|

x(1 -
] x (1 -
] X(1 -
I X(1 -

16%
Municipal WW.

1.751x1 0.001 l=l 50.816 l-l~	8 l = I 50.808 I x fl ¦ l~	11x1

N20, direct \ Municipal WW, N20, effluent / Ind WW Fruit / Ind WW Meat / Ind WW Poultry | <

Sewage sludge is often applied to agricultural fields as fertilizer. Emissions from this use
should be accounted for under Agricultural Soil Management. The Agriculture module of the
SIT is designed to calculate emissions from sewage sludge applied to land, but to be
consistent, users need to enter the percentage of sewage sludge applied to agricultural soils
in the second column of orange cells in order to not double-count emissions, as shown in
Figure 6. At this time, there is no default data for the percentage of biosolids used as
fertilizer.

Click on the gray navigational arrow to estimate ChU emissions from the industrial
wastewater sectors selected on the control worksheet.

Step (7) Complete Industrial Wastewater ChU - Fruits and Vegetables
Worksheet

This worksheet calculates emissions from wastewater used for fruits and vegetables. Please
enter the amount of fruits and vegetables processed in metric tons in the yellow cells, as
shown in Figure 7.

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.11

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Module 10 - Wastewater Module

January 2023

Figure 7. Example of Industrial Wastewater ChU - Fruits and Vegetables

Worksheet

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Emissions from treatment of industrial wastewater from fruit and vegetables is based annual metric tons produced and
factored by the volume of wastewater produced per unit production, the average organic matter content of wastewater
from those processes, a CH« emission factor, the percent treated anaerobically, converted to million metric tons carbon
equivalent (MMTCE), and converted to million metric tons carbon dioxide equivalent (MMTCCuE). The methodology and
factors used for these calculations are discussed in detail in the Wastewater Chapter of the User's Guide.



Continue to the^x
Next Sheet





\. are

avai loble.

/



Clear All Data



3

1

Production
Processed

VV Unit
Outflow Conversion

COD

Emission COD Unit
Factor Degraded Emissions Conversion Emissions

CH,
GVP



C/COz Emiss



4



(metric tons)

(m'fmetric ton) flfm']

(g CODJI)

(q ChMq COD) (percent)

qCH,l

(g'Tgl (Tgo

MMT cm

(CQi Eg.)



fMMT



b





6

19*0



>

5.6|x|

1,000 |x|

51 x

0.25 |x| 5%| = |

- M

1E-121 = |



t>

21

H

0.27 |=| (



/





8

1991





5.6H

1,000 |x|

51 x

0.25 |x| 5%| = |

- M

1E-121 = |





21

H

0.27 |=| (



y





10

1992



>

5.6 X

1,000 I x

51 x

0.25 | x | 5% | = |

- M

1 E-121 = |



• |x |

21

H

0.27 |=| (



11





12

1993



>

5.6 x

1,000 | x

5|x

0.25 |x | 5% | = |

- M

1 E-121 = |



• |x

21

H

0.27 |=| (



13





14

1994

<

IS.

5.61x1

1,000 | x

S|x

0.25 |x | 5% | = |

- M

1 E-121 = |





21

>[

0.27 |=| (



1b





16

1995





5.6X-[

0.27 | = | \

31





























32

2003 [



It

"ii]x|

1,000 |xf

51 x f

0.25 |x| 5%| = |

- It

1 E-121 = |





21

H

0.27 | = | (



H *

~ ~! \ Control / Municipal WW, CH4 / Municipal WW, N20, direct / Municipal WW, N20, effluent \lnd WW Fruit/ Ind WW Meat / Ind WW Poults] < |

Emissions from treatment of industrial wastewater from processing fruits and vegetables are
based on annual production in metric tons, multiplied by the volume of wastewater
produced per unit production, the average organic matter content of wastewater from those
processes, the ChU emission factor, the percent treated anaerobically, and then converted to
MMTCO2E as shown in Equation 4.

Equation 4. ChU Emissions from Industrial Wastewater for Fruits and Vegetables

CH4 Emissions (MMTCO2E) =

Production Processed (Metric Tons) x Wastewater Produced (m3/metric ton) x
1,000 (L/m3) x Organic Matter Content (g COD/L) x
Emission Factor (g ChU/g COD) x Percent Treated Anaerobically (%) x

1012 (MMT/g) x 25 (GWP)

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.12

-------
Module 10 - Wastewater Module

January 2023

Step (8) Complete Industrial Wastewater ChU - Red Meat Worksheet

This worksheet calculates emissions from wastewater from red meat processing. In the pink
cells, enter the amount of red meat processed in metric tons, as shown in Figure 8.

Figure 8. Example of Industrial Wastewater ChU - Red Meat Worksheet

P 0 I

~ State Inventory Tool - Wastewater Module

I File Edit Module Options

A | B

H

I

K

M N

~0®

Type a question for help •» _ i9 X

t IT v vT x

8 Colorado Industrial Wastewater Methane - Red Meat

Click here to find
where these data
are avai loble.

Emissions from treatment of industrial wastewater from red meat is based annual metric tons produced and factored by the volume of
wastewater produced per unit production, the average organic matter content of wastewater from those processes, a CHt emission
factor, the percent treated anaerobically, converted to million metric tons carbon equivalent (MMTCE), and converted to million metric
tons carbon dioxide equivalent (MMTCO-E). The methodology and factors used for these calculations are discussed in detail in the

Continue
Next

e to the\

J





Production



vv



Unit



Emission

COD





Unit





iSelectAllpefauftsj
CH,



3



Processed



Outflow



Conversion

COD

Factor

Degraded

Emissions



Conversion

Emissions



GVP CJCO,

Emissioi

4



(metric tons)

(mVmetric ton)

(I'm')

(q COOfl)

fqCH,fqCODl

(percent)

fq CHd



fq'Tq)

(TqorMMTCH,



(COs Eq.)

[MMTCE

5









x

X
X























6

19*0 |

720,997.20

*

8

1,000 | x |

4.1

0.25 | X

33% | = |

1,926,630,693

X

1E-121 =

0.00

X

21 |x| 0.27 |-

0.0

I































8

1991 |

795,523.68

*

8

1,000 | x |

4.1

0.25 | X

33% | = |

2,125,778,490

X

1E-121 =

0.00

X

21 |x| 0.27 |-

0.0

y































10

1992 |

878,577.84

*

8

1,000 |x|

4.1

0.25 | X

33% | = |

2,347,713,740

X

1 E-121 =

0.00

X

21 |x| 0.27 |-

0.0

11































12

1993 |

861,522.48

*

8

X

1,000 |x|

4.1

0.25 | X

33% | = |

2,302,138,833

X

1 E-121 =

0.00

X

21 |x| 0.27 |-

0.0

13































14

1994 |

885,74U2

X

8

X

1,000 |x|

4.1

0.25 | X

33% | = |

2,366,864,897

X

1 E-121 =

0.00

X

21 |x| 0.27 |-

0.0

1 b





























16

1995 |

917.26TO2

X



X

1.000 Ixl

4.1 |x

0.25 Ix

33% I = I

2,451,105,748

X

1 E-121 =

0.00

X

21 |x| 0.27 |-

0.0

17









Enter Production Processed















18

199$ |

921,034.80



8

2,461,166,167

X

1 E-121 =

0.00

X

21 |x| 0.27 |-

0.0

iy



































20

1997 |

919,311.12



8

X

1,000 |x|

4.1

0.25 | x

33% | = |

2,456,560,192

X

1 E-121 =

0.00

X

21 |x| 0.27 |-

0.0

21

































22

1998 |

887,014.80



8



1,000 |x|

4.1

0.25 | x

33% | = |

2,370,258,773

X

1 E-121 =

0.00

X

21 |x| 0.27 |-

0.0

23

































24

1999 |

969,751.44

»

8

X
X
X
X
X

1,000 |x|

4.1

0.25 | x

33% | = |

2,591,345,554

X

1 E-121 =

0.00

X

21 |x| 0.27 |-

0.0

2b































26

2000 |

975,421.44

X

8

1,000 |x|

4.1

0.25 | x

33% | = |

2,606,496,786

X

1 E-121 =

0.00

X

21 |x| 0.27 |-

0.0

21































28

2001 |

969,887.52

X

8

1,000 |x|

4.1

0.25 | x

33% | = |

2,591,709,184

X

1 E-121 =

0.00

X

21 |x| 0.27 |-

0.0

2y































30

2002 |

991,070.64

X

8

1,000 |x|

4.1

0.25 | x

33% | = |

2,648,314,187

X

1 E-121 =

0.00

X

21 |x| 0.27 | =

0.0

31































32

2003 I

898,989.84

*

8

1,000 |x|

4.1

0.25 | x

33% | = |

2,402,258,176

X

1 E-121 =

0.00

X

21 |x| 0.27 | =

0.0

~i \ Control I Municipal WW, CH4 / Municipal WW, N20, direct / Municipal WW, N20, effluent / Ind WW Fruit \lnd WW Meat/ Ind WW Poultry |<

Emissions from treatment of industrial wastewater from red meat are based on annual
production in metric tons, multiplied by the volume of wastewater produced per unit
production, the average organic matter content of wastewater from those processes, the
CH4 emission factor, the percent treated anaerobically, and then converted to MMTCO2E as
shown in Equation 5. Default data on red meat production are available from USDA (2022).

Equation 5. ChU Emissions from Industrial Wastewater for Red Meat

CH4 Emissions (MMTCO2E) =

Production Processed (Metric Tons) x Wastewater Produced (m3/metric ton) x
1,000 (L/m3) x Organic Matter Content (g COD/L) x
Emission Factor (g ChU/g COD) x Percent Treated Anaerobically (%) x

1012 (MMT/g) x 25 (GWP)

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.13

-------
Module 10 - Wastewater Module

January 2023

Step (9) Complete Industrial Wastewater ChU - Poultry Worksheet

This worksheet calculates emissions from wastewater used for poultry. The required input
is amount of production processed in metric tons in the purple cells, as shown in Figure 9.

Figure 9. Example of Industrial Wastewater ChU - Poultry Worksheet

E3 State Inventory Tool -

Wastewater Module





















¦a;

File Edit

Module Options





















1 Type a question for help

"fll- fi1 X



A B

C

Id

E |F|

G |H|

i |j|

K |L

M N



0

P

0 R

s

t u_|y w x

| Y *

1

9 Colorado Industrial Wastewater Methane -

Poultry

















































f Click here to find



Emissions from treatment of industrial wastewater from poultry is based annual metric tons produced and factored by
the volume of wastewater produced per unit production, the average organic matter content of wastewater from



Continue to th^\
Next Sheet



2

are available.

J

equivalent (MMTCE), and converted to million metric tons carbon dioxide equivalent (MMTCO^). The methodology and
factors used for these calculations are discussed in detail in the Wastewater Chapter of the User's Guide.



Clear All Data |



3



Production
Processed

VV Unit
Outflow Conversion

COD

Emission

COD
Degraded

Emissions



Unit CH,

Conversion Emissions GVP CfCOi

Emission

4

r

(metric tonsi

i (mVmetric ton)

fl'm'l

(q CCOI)

(gCH,fgCOD)

(percent)



(qCH,)



(g(Tg) (TqorMMTCH,) (COiEq.)

(MMTCE

b

1

6

19*0 [



M

17 |x |

1,000 |x|

4.1 | X |

0.25 | X

25.0%|= |





»

1E-121 = |



~\x\ 21 |x| 0.27 | =

on

I



8

1991 [



M

17|x |

1,000 |x|

4.1 | X |

0.25 | X

25.0%|= |







1E-121 = |



Jx 21 |x| 0.27 | =

0H

y



10

1992 [



M

17|x I

1,000 |x|

4.1 | X |

0.25 | X

25.0%|= |





*

1 E-121 = |



Jx 21 |x| 0.27 |.

OH

11



12

1993 [



M



1,000 |x|

4.11 x |

0.25 | x

25.0%|= |







1 E-121 = |



Jx 21 |x| 0.27 | =

OH

13



14

1994 [

1

: L



1,000 |x|

4.11 x |

0.25 | x

25.0%|= |





>

1 E-121 = |



Jx 21 |x| 0.27 | =

OH

15



16

1995 [



>r

j'lj

Enter Production Processed

¦

>

1 E-121 = |



Jx 21 |x| 0.27 |-

OH

17

J

	. .	. .	, .	. .	. .	

18

199< 1



M

17|x

' 1JJUU |x|

4.1 |i<|

im |y|

^b.U%| = |

	



Jxl

1 E-121 = |



Jx 21 |x| 0.27 |-

OH

19



20

1997 [



>r



1,000 |x[

4.1 |x[

0.25 |x[

25.0%| = \





>

1 E-121 = |



\x\ 21 |x| 0.27 | =

OH

21

1

22

1998 [



>r



1,000 |x|

4.1 |x[

0.25 | x [

25.0%| = |





>

1 E-121 = |



|x| 21 |x| 0.27 | =

OH

23



24

1999 [



>r



1,000 | x [

4.1 |x[

0.25 | x f

25.0%| = \





>

1 E-121 = |



|x| 21 |x| 0.27 | =

oot

25

1

26

2000 [





jC

1,000 |x|

4.1 |x[

0.25 | x [

25.0%| = \





>

1 E-121 = |



|x| 21 |x| 0.27 | =

oot

27



28

2001 [





171 x |

1,000 |x|

4.1 |x[

0.25 |x[

25.0%| = |





>

1 E-121 = |



\x\ 21 |x| 0.27 | =

oot

29



30

2002 [





171 x |

1,000 |x|

4.1 |x[

0.25 | x [

25.0%| = |





>

1 E-121 = |



\x\ 21 |x| 0.27 | =

oot

31



32

2003 [



>L



1,000 |x|

4.1 |x[

0.25 | x [

25.0%| = |





>[

1 E-121 = |



Jx\ 21 |x| 0.27 |-

OH































V

I< i

~ / Municipal WW, N20, direct / Municipal WW, N20, effluent / Ind WW Fruit / Ind WW Meat \lnd WW Poultry / Ind WW P&P / Summary / Un | <

>

Equation 6 shows that emissions from treatment of industrial wastewater from poultry are
based on annual production in metric tons, multiplied by the volume of wastewater
produced per unit production, the average organic matter content of wastewater from those
processes, the ChU emission factor, the percent treated anaerobically, with the total then
converted to MMTCO2E.

Equation 6. ChU Emissions from Industrial Wastewater for Poultry

CH4 Emissions (MMTCO2E) =

Production Processed (Metric Tons) x Wastewater Produced (m3/metric ton) x
1,000 (L/m3) x Organic Matter Content (g COD/L) x
Emission Factor (g ChU/g COD) x Percent Treated Anaerobically (%) x

1012 (MMT/g) x 25 (GWP)

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.14

-------
Module 10 - Wastewater Module

January 2023

Step (10) Complete Industrial Wastewater ChU - Pulp and Paper Worksheet

This worksheet calculates emissions from wastewater used for pulp and paper. The
required data (in the green cells) is the amount in metric tons of (1) woodpulp and (2)
paper and paperboard processed, as shown in Figure 10.

Figure 10. Example of Industrial Wastewater ChU - Pulp and Paper Worksheet

E State Inventory Tool -

Wastewater Module



















File Edit Module Options

















Type a question for help

E - B

X



A | B

|C| D

E

F G

H 11

J |K

L M

N 0



P |Q| R

1

| T |U| V

w

A

1

10

Colorado Industrial Wastewater Methane - Pulp & Paper















f Click here to fine
1 where these data
\. are available.



Emissions from treatment of industrial wastewater from pulp and paper production is based annual metric tons
produced and factored by the volume of wastewater produced per unit production, the average organic matter
content of wastewater from those processes, a CH4 emission factor, the percent treated anaerobically, converted to
million metric tons carbon equivalent (MMTCE), and converted to million metric tons carbon dioxide equivalent
(MMTCO-E). The methodology and factors used for these calculations are discussed in detail in the Wastewater



Continue to the
Next Sheet





2

)



Clear All Data |











Chapter of the User's Guide.



















3

~T



Production Processed VV

(metric tons) Outflow
Woodpulp Paper & Paperboard fmVmetric ton)

Unit
Conversion

(I'm')

BOD
Degraded

(g BOD i 1)

Emission

(gCH,fgBOD)

TA Emissions

(percent) (g CH,)



Unit 1
Conversion Emissions C

(g'Tg) [Tg or MMT CH,) (C



5





























6

1990



1E-121 = |

~c



y





























10

1992

<1

IH

1 > x|

851 x

1,000 | x

0.4 |x

0.6 | X

10.3% | = |

>

1 E-121 = |

u*\z



11





























12

1993

<1

J-L

1 > x|

851 x

1,000 | x

0.4 |x

0.6 | x

10.3% | = |

>

1 E-121 = |





13





























14

1994

<1



|) xf

851 x

1,000 | x

0.4 |x

0.6 | X

10.3% | = |

>

1E"12I =

ZI-II



15





























16

1995

<1

m



851 x

1,000 | x

0.4 |x

0.6 | X

10.3% | = |

>

1 E-121 = |

ZI-II



17





























18

199«

<1



^.1 »T



1,000 | x

0.4 |x

0.6 | x

10.3% | = |

>

1 E-121 = |





19









1 •









I	



20

1997

<1



1^

Enter Production Processed



|o.3% | = |

>

1 E-121 = |





21









1







	





22

1998

<1



l» x[

851 x

1,000 | x

0.4 |x

0.6 | x

10.3% | = |

>

1E"12I =





23





























24

1999

<1



|> xf

851 x

1,000 | x

0.4 |x

0.6 | x

10.3% | = |

>

1 E-121 = |

~ | X |



25





























26

2000

<1



|> xf

85 |x

1,000 | x

0.4 |x

0.6 | x

10.3% | = |

>

1 E-121 = |

~ | X |



27





























28

2001

<1

>11

|> xf

851 x

1,000 | x

0.4 |x

0.6 | x

10.3% | = |

>

1 E-121 = |

~ |x|



29





























30

2002

<1



|) xf

851 x

1,000 | x

0.4 |x

0.6 | x

10.3% | = |

>

1 E-121 = |

~ |x |



31





























32

2003

<1



|> xf

851 x

1,000 | x

0.4 |x

0.6 | x

10.3% | = |

>

1 E-121 = |

|x|

V

N *

~ h / Municipal WW, N20, direct / Municipal WW, N20, effluent / Ind WW Fruit / Ind WW Meat / Ind WW Poultry >, Ind WW P8

IP J Summary / Un | <

I) ill |

As shown in Equation 7, emissions from treatment of industrial wastewater from pulp and
paper are based on annual woodpulp, paper, and paperboard produced in metric tons,
multiplied by the volume of wastewater produced per unit production, the average organic
matter content of wastewater from those processes, the Chk emission factor, and the
percent treated anaerobically. The total emissions are then converted to MMTCO2E.

Equation 7. CH4 Emissions from Industrial Wastewater for Pulp and Paper

CH4 Emissions (MMTCO2E) =

[Production Processed Woodpulp (Metric Tons) + Production Processed Paper &
Paperboard (Metric Tons)] x Wastewater Produced (m3/metric ton) x 1,000
(L/m3) x Organic Matter Content (g BOD/L) x
Emission Factor (g ChU/g BOD) x Percent Treated Anaerobically (%) x

1012 (MMT/g) x 25 (GWP)

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.15

-------
Module 10 - Wastewater Module

January 2023

Step (11) Review Summary Information

The steps above provide estimates of total emissions from wastewater. The information
from the control worksheet and data entry worksheets is collected on the summary
worksheet, which displays results in MMTCO2E. Figure 11 shows the summary worksheet
that sums the emissions from all sectors in the Wastewater module. In addition, the results
are displayed in graphical format at the bottom of the summary worksheet.

Figure 11. Example of the Emissions Summary Worksheet in the Wastewater
Module

E State Inventory Tool - Wastewater Module

SJ File Edit Module Options

11. California Emissions Summary

Return to Control
Sheet

Review discussion of
uncertainty associated
with these results

Emissions were not calculated for the following sources: Industrial Fruits d Vegetables, and Industrial Pulp & Paper.

Emissions (MMTCO.E)

1»»0 19U 1»»2 im 1»»4 1*»S 1»*7 1*»8 2000 2001 2002 2003

Municipal CH,
Municipal NrO
Industrial CH,

Fruits A Vegetables
Red Meat
Poultry
Pulp 6 Paper

2.00 2.05 2.08 2.09

2.11 2.12 2.14

2.23
0.96

Total Emissions

2.84 2.91 2.97 2.99 3.02 3.03 3.07 3.10 3.15 3.21 3.30 3.37 3.39

Total Wastewater Emissions, 1990-2020

- Municipal CH4 -"—Municipal N20 —Industrial CH4

Methane Emissions from Industrial Wastewater

— Fruits & Vegetables —Red Meat k Pulp & Paper

1990-2020

Poultry

£ 0.03
f, 0.03
i 002

J 0.02

0.01
0.01

Step (12) Export Data

The final step is to export the summary data. Exporting data allows the estimates from
each module to be combined later by the Synthesis Module to produce a comprehensive
greenhouse gas inventory for the state.

To access the "Export Data" button, return
to the control worksheet and scroll down to
step 12. Click on the "Export Data" button
and a message box will open that reminds
the user to make sure all steps of the
module have been completed. If you make
any changes to the Wastewater module
later, you will then need to re-export the
results.

Note: the resulting export file should not be
modified. The export file contains a summary
worksheet that allows users to view the results, as well as
a separate data worksheet with an unformatted version of
the results. The second worksheet, the data worksheet,
contains the information that is exported to the Synthesis
Tool. Users may not modify that worksheet...
Adding/removing rows, moving data, or making other
modifications jeopardize the ability of the Synthesis
Module to accurately analyze the data.

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.16

-------
Module 10 - Wastewater Module

January 2023

Clicking "OK" prompts you to save the file. The file is already named, so you only need to
choose a convenient place to save the file. After the file is saved, a message box will appear
indicating that the data was successfully exported.

While completing the modules, you are encouraged to save each completed module; doing
so will enable you to easily make changes without re-running it entirely.

Following data export, the module may be reset and run for an additional state.

Alternatively, you may run the remaining modules of the SIT to obtain a comprehensive
profile of emissions for your state.

1.4 Uncertainty

In the upper right-hand corner of the summary worksheet is a button: "Review discussion of
uncertainty associated with these results." By clicking on this button, you are taken to a
worksheet that discusses the uncertainty surrounding the activity data and emission factors,
and how the uncertainty estimates for this source category affect the uncertainty of the
emission estimates for your state.

1.5 References

IPCC. 2006. 2006 IPCC Guidelines for National Greenhouse Gas Inventories, 5 volumes.
Intergovernmental Panel on Climate Change, United Nations Environment Programme,
Organization for Economic Co-Operation and Development, International Energy Agency.
Paris, France.

Spector, M. 1997. "Production and Decomposition of Nitrous Oxide During Biological
Denitrification." Unpublished, Lehigh University. Bethlehem, PA.

U.S. Census Bureau. 2021. National Population Totals and Components of Change: 2010-
2020. U.S. Census Bureau, Washington, DC. Available online at:
http://www .census, gov.

U.S. EPA. 2022a. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2020.

Office of Atmospheric Programs, U.S. Environmental Protection Agency. EPA 430-R-22-
003. Available online at: https://www.epa.gov/ohgemissions/inventorv-us-oreenhouse-
aas-emissions-and-sinks.

U.S. EPA. 2022b. Inventory of U.S. Greenhouse Gas Emissions and Sinks By State: 1990 -
2020. Office of Atmospheric Programs, U.S. Environmental Protection Agency. Available
at:

https://www.epa.aov/svstem/files/documents/202208/StateGHGI Methodology Report
August 2022.pdf.

USDA. 2022. Red Meat Production, U.S. Department of Agriculture, National Agriculture
Statistics Service, Washington, DC. September 2022. Data available online at:
https://guickstats.nass.usda.gov/.

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.17

-------
Module 10 - Wastewater Module	January 2023

State Greenhouse Gas Inventory Tool User's Guide for the Wastewater Module 1.18

-------