TECHNICAL SUPPORT DOCUMENT FOR
INDUSTRIAL WASTEWATER TREATMENT:
FINAL RULE FOR MANDATORY REPORTING
OF GREENHOUSE GASES
Climate Change Division
Office of Atmospheric Programs
U.S. Environmental Protection Agency
June 2010

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CONTENTS
Page
1.	Introduction and Background	1-1
2.	Industry Description	2-1
2.1	Industrial Wastewater Treatment	2-1
2.2	Reporting Rule Applicability	2-3
2.2.1	Processes Included in the Reporting Rule	2-3
2.2.2	Industries Included in the Reporting Rule	2-4
3.	Emission Estimates	3-1
3.1	Pulp and Paper Mills	3-1
3.2	Food Processing Facilities	3-2
3.3	Ethanol Production Facilities	3-5
3.4	Petroleum Refineries	3-6
3.5	Summary	3-7
4.	Estimating Methane Generation from Wastewater Treatment	4-1
4.1	Flow Measurement	4-3
4.2	Organic Matter Concentration Measurement and Analysis	4-4
5.	Estimates of Methane Recovery	5-1
5.1	Biogas Flow Measurement	5-3
5.2	Biogas Composition Monitoring	5-3
6.	Methane Emissions Calculation	6-1
7.	Costs for GHG Reporting	7-1
8.	References	8-1
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LIST OF TABLES
Page
3-1 Values Used to Estimate Pulp and Paper CH4 Emissions	3-2
3-2 Values Used to Estimate Meat and Poultry Processing CH4 Emissions	3-4
3-3 Values Used to Estimate Ethanol Production CH4 Emissions	3-5
3-4 Values Used to Estimate Petroleum Refinery CH4 Emissions	3-6
3-5	Estimated Number of Plants Required to Report and Estimated Emissions	3-7
4-1	Emission Factors	4-3
6-1	Collection Efficiencies of Anaerobic Processes	6-2
7-1	Industrial Wastewater Treatment Monitoring Costs	7-2
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LIST OF FIGURES
Page
2-1 Diagram of Wastewater Treatment Inputs and Outputs	2-2
4-1	Methane Generation	4-1
5-1	Diagram of Biogas Recovery from Anaerobic Wastewater Treatment	5-1
5-2	Diagram of Biogas Recovery from Anaerobic Sludge Digestion	5-2
6-1	Diagram of Leakage From Anaerobic Sludge Digestion Biogas Recovery	6-1
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1. Introduction and Background
This document supports the Mandatory Reporting of Greenhouse Gases Final Rule
(Reporting Rule) for the industrial wastewater treatment source category. The rule is divided into
industry-specific categories and other categories that span industries. Categories that span
industries include stationary fuel combustion sources, industrial landfills, and industrial
wastewater treatment. EPA proposed reporting requirements for the wastewater treatment source
category in the Federal Register on April 10, 2009, under Subpart II. EPA received comments on
this subpart and revised the proposed regulation. The major changes from the proposed rule
include:
•	Renaming the source category Industrial Wastewater Treatment;
•	Clarifying the subpart's applicability;
•	Removing reporting requirements for petroleum refining oil/water separators and
petrochemical facilities; and
•	Revising monitoring requirements.
This document provides technical support for the final rule.
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2. Industry Description
The industrial wastewater treatment source category of the Reporting Rule specifically
applies to anaerobic processes used to treat industrial wastewater and industrial wastewater
treatment sludge at facilities that perform pulp and paper manufacturing, food processing,
ethanol production, and petroleum refining. This section describes industrial wastewater
treatment, including the anaerobic treatment operations covered under the Reporting Rule, and
explains how the Reporting Rule applies to this source category.
2.1 Industrial Wastewater Treatment
Wastewater treatment refers to processes that treat or remove pollutants and
contaminants, such as soluble organic matter, suspended solids, pathogenic organisms, and
chemical contaminants, from wastewater prior to its reuse or discharge from the facility. These
pollutants and contaminants are removed from wastewater using physical and chemical
processes (such as sedimentation and chlorine disinfection) and biological processes. Biological
wastewater treatment processes can produce C02 and anthropogenic CH4 and N20 emissions.
Industrial wastewater may be treated either on site at an industrial facility (industrial
wastewater treatment) or in combination with municipal wastewater at a centralized publicly
owned treatment plant (POTW) or privately owned treatment plant. Industrial wastewater is
defined as water that comes into direct contact with or results from the storage, production, or
use of any raw material, intermediate product, finished product, by-product, or waste product.
Examples of industrial wastewater include, but are not limited to, paper mill white water,
wastewater from equipment cleaning, wastewater from air pollution control devices, rinse water,
contaminated stormwater, and contaminated cooling water. Municipal wastewater treatment
refers to a series of treatment processes used to remove contaminants and pollutants from
domestic, business, and industrial wastewater collected in city sewers and transported to a
centralized wastewater treatment system such as a POTW.
Soluble organic matter is generally removed from wastewater using biological processes
in which microorganisms consume the organic matter for maintenance and growth. The resulting
biomass and other suspended solids, together known as sludge, are removed from the treated
wastewater before it is discharged to a receiving stream. Microorganisms can biodegrade soluble
organic material in wastewater under aerobic or anaerobic conditions. Anaerobic wastewater
treatment refers to the procedure in which organic matter in wastewater or other material is
degraded by microorganisms in the absence of oxygen, resulting in the generation of CO2 and
CH4.
Figure 2-1 shows a simplified diagram outlining the inputs and outputs from wastewater
treatment operations. Typically, treatment of wastewater begins with primary treatment using
processes such as screening or settling. Subsequently, wastewater may be biologically treated
either under aerobic or anaerobic conditions. Most biological treatment processes are designed to
separate solids from wastewater; often, these solids are treated further in sludge digesters, which
may be either aerobic or anaerobic.
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Primary Treatment
Aerobic or Anaerobic
Biological Wastewater
Treatment Operations
Aerobic or Anaerobic
Sludge Digestion
Raw
Wastewater
Liquids Returned to Treatment
Solids
CH4 co2 n2o
Solids
Treated
Wastewater
Solids to
Disposal
Figure 2-1. Diagram of Wastewater Treatment Inputs and Outputs
As shown in Figure 2-1, both biological wastewater treatment and sludge digestion
generate greenhouse gases (GHGs). Aerobic processes emit C02; however, these are not
considered anthropogenic emissions and therefore are neither included in Inventory of U.S.
Greenhouse Gas Emissions and Sinks (EPA, 2007) (hereafter referred to as the Inventory) nor in
the Reporting Rule. Because CO2 released from wastewater treatment is biogenic in origin (i.e.,
produced by biological processes), the Intergovernmental Panel on Climate Change (IPCC)
considers these CO2 emissions to be part of the natural carbon cycle.
Domestic and some industrial wastewaters contain nitrogen, usually in the form of urea,
ammonia, and proteins. These compounds are converted to nitrate (NO3) through the aerobic
process of nitrification. Denitrification occurs under anoxic conditions (without free oxygen),
and involves the biological conversion of nitrate into di-nitrogen gas (N2). N2O can be an
intermediate product of both processes, but is more often associated with denitrification.
Industrial wastewater is generally low in nitrogen and, as a result, its treatment generates little
N20. Emissions of N20 from industrial wastewater treatment are not included in either the
Inventory or the Reporting Rule. The IPCC has stated that the N2O emissions from industrial
sources are insignificant compared to emissions from domestic wastewater.
The only GHG accounted for in Subpart II of the Reporting Rule is CH4. The principal
factor in determining the CH4 generation potential of wastewater is the amount of degradable
organic material in the wastewater. Common parameters used to measure the organic component
of the wastewater are Biochemical Oxygen Demand (BOD5) and Chemical Oxygen Demand
(COD). BOD5 represents the amount of oxygen used by microorganisms to consume the organic
matter contained in the wastewater through aerobic decomposition processes in a 5-day period.
COD measures the total material available for chemical oxidation (both biodegradable and non-
biodegradable).
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2.2 Reporting Rule Applicability
The requirements of Subpart II apply to anaerobic processes used to treat industrial
wastewater and wastewater treatment sludges at pulp and paper mills, food processing facilities,
ethanol production facilities, and petroleum refineries. These are the only industries covered by
Subpart II. Further, Subpart II does not include emissions from:
•	Municipal wastewater treatment plants;
•	Separate treatment of sanitary wastewater at industrial facilities;
•	Oil/water separators; or
•	Aerobic and anoxic treatment of industrial wastewater.
2.2.1 Processes Included in the Reporting Rule
The anaerobic treatment processes covered by Subpart II are those processes in which
organic matter in wastewater or wastewater treatment sludge is degraded by microorganisms in
the absence of oxygen, resulting in biogas generation. "Biogas" refers to the combination of
CO2, CH4, and other gases produced by the biological breakdown of organic matter in the
absence of oxygen (Metcalf & Eddy, 1979).
Requirements for this source category require facilities to report CH4 emissions only
from anaerobic processes and related biogas destruction devices. Anaerobic processes are
biological processes that occur in the absence of oxygen (Metcalf & Eddy, 1979). Facilities are
required to report CH4 emissions from anaerobic reactors and anaerobic lagoons used to treat
industrial wastewater and from anaerobic sludge digesters used to treat industrial wastewater
treatment sludges. The sludges may be produced by either aerobic or anaerobic wastewater
treatment processes. Facilities are also required to report methane emissions from devices used to
destroy the biogas recovered from the anaerobic processes.
Anaerobic reactors. Anaerobic reactors are enclosed vessels used for anaerobic
wastewater treatment processes (Grady, Daigger, and Lim, 1999; Metcalf & Eddy, 1979). The
IPCC methodology for estimating CH4 emissions from industrial wastewater treatment identifies
two types of anaerobic reactors, anaerobic sludge blanket and fixed film (IPCC, 2006;
Table 6-8).
Anaerobic lagoons. Anaerobic lagoons are lined or unlined earthen basins used for
wastewater treatment, in which oxygen is absent throughout the depth of the basin, except for a
shallow surface zone (Metcalf & Eddy, 1979). Anaerobic lagoons are not equipped with surface
aerators. The IPCC methodology for estimating CH4 emissions from industrial wastewater
treatment classifies anaerobic lagoons into two depths: deep (depth more than 2 meters) or
shallow (depth less than 2 meters) (IPCC, 2006; Table 6-8).
Anaerobic sludge digesters. Anaerobic sludge digesters are enclosed vessels in which
wastewater treatment sludges are degraded by microorganisms in the absence of oxygen,
resulting in the generation of CO2 and CH4 (Metcalf & Eddy, 1979). The digested wastewater
treatment sludges may have been generated by aerobic treatment processes (e.g., the activated
sludge process). If the sludge digester is operated in the absence of oxygen, it is considered an
anaerobic process. Anaerobic sludge digesters are designed for CH4 recovery and are not
expected to emit methane directly from the digester. The IPCC methodology for estimating CH4
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emissions from industrial wastewater treatment includes a methodology for estimating emissions
from "anaerobic digester for sludge" (IPCC, 2006; Table 6-8).
Biogas destruction devices. Biogas destruction devices include flares, thermal oxidizers,
boilers, turbines, internal combustion engines, or any other combustion units used to destroy or
oxidize CH4 contained in biogas.
2.2.2 Industries Included in the Reporting Rule
Subpart II includes industries that both have high levels of BOD5 or COD in their
wastewater and frequently use anaerobic treatment. For these reasons, these industries are also
represented in the wastewater treatment sector of the U.S. GHG Inventory. These industries (pulp
and paper mills, food processing facilities, ethanol production facilities and petroleum refineries)
are described in more detail below.
Pulp and Paper Mills. Pulp and paper mills are facilities that produce market pulp (i.e.,
stand-alone pulp facilities), manufacture pulp and paper (i.e., integrated facilities), produce paper
products from purchased pulp, produce secondary fiber from recycled paper, convert paper into
paperboard products (e.g., containers), or operate coating and laminating processes (40 CFR
§98.270).
Wastewater treatment for the pulp and paper industry typically includes primary
treatment (such as screening, sedimentation, and flotation/hydrocycloning) to remove solids
(World Bank, 1999; Nemerow and Dasgupta, 1991), followed by secondary biological treatment
(such as activated sludge or anaerobic or aerobic lagoons). In the United States, primary
treatment is focused on solids removal, equalization, neutralization, and color reduction (EPA,
1993). The vast majority of pulp and paper mills with on-site treatment systems use mechanical
clarifiers to remove suspended solids from the wastewater. About 10 percent of pulp and paper
mills with treatment systems use settling ponds for primary treatment and most of these likely do
not perform secondary treatment (EPA, 1993). Negligible GHG emissions are assumed to occur
during primary treatment.
Approximately 42 percent of the BOD5 in pulp and paper wastewater passes on to
secondary treatment, which consists of activated sludge, aerated stabilization basins, or non-
aerated stabilization basins (EPA, 1997b). No anaerobic activity is assumed to occur in activated
sludge systems or aerated stabilization basins. However, for the Inventory, EPA assumes about
25 percent of the wastewater treatment systems used in the United States are nonaerated
stabilization basins. These basins are typically 10 to 25 feet deep and are classified as anaerobic
deep lagoons.
Food Processing Facilities. For the purpose of the Reporting Rule, food processing
facilities are defined as those that manufacture or process meat, poultry, fruits, and/or vegetables.
The North American Industry Classification System (NAICS) is the standard used by federal
statistical agencies in classifying business establishments for the purpose of collecting,
analyzing, and publishing statistical data related to the U.S. business economy. It was developed
in 1997 to replace the Standard Industrial Classification (SIC) system (NAICS, 2007).
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Meat or poultry processing or rendering facilities are those covered under NAICS code
3116 (which was SIC code 201, Meat Product Manufacturing). NAICS code 3116 (Animal
Slaughtering and Processing) is made up of the following subsectors:
•	31161 Animal Slaughtering and Processing
This industry comprises establishments primarily engaged in one or more of the
following: (1) slaughtering animals; (2) preparing processed meats and meat by-
products; and (3) rendering and/or refining animal fat, bones, and meat scraps.
This industry includes establishments primarily engaged in assembly cutting and
packing of meats (i.e., boxed meats) from purchased carcasses.
•	311611 Animal (except Poultry) Slaughtering
This U.S. industry comprises establishments primarily engaged in slaughtering
animals (except poultry and small game). Establishments that slaughter and
prepare meats are included in this industry.
•	311612 Meat Processed from Carcasses
This U.S. industry comprises establishments primarily engaged in processing or
preserving meat and meat by-products (except poultry and small game) from
purchased meats. This industry includes establishments primarily engaged in
assembly cutting and packing of meats (i.e., boxed meats) from purchased meats.
•	311613 Rendering and Meat By-product Processing
This U.S. industry comprises establishments primarily engaged in rendering
animal fat, bones, and meat scraps.
•	(311614 is not a valid 2007 NAICS code)
•	311615 Poultry Processing
This U.S. industry comprises establishments primarily engaged in (1) slaughtering
poultry and small game and/or (2) preparing processed poultry and small game
meat and meat by-products.
Fruit or vegetable processing facilities are facilities covered under NAICS code 3114
(which was SIC code 203, Fruit and Vegetable Preserving and Specialty Food Manufacturing).
NAICS code 3114 (Fruit and Vegetable Preserving and Specialty Food Manufacturing) includes
the following: (1) establishments that freeze food and (2) those that use preservation processes,
such as pickling, canning, and dehydrating. Both types begin their production process with inputs
of vegetable or animal origin.
NAICS 3114 (Fruit and Vegetable Preserving and Specialty Food Manufacturing) is
made up of the following subsectors:
•	31141 Frozen Food Manufacturing
This industry comprises establishments primarily engaged in manufacturing
frozen fruit, frozen juices, frozen vegetables, and frozen specialty foods (except
seafood), such as frozen dinners, entrees, and side dishes; frozen pizza; frozen
whipped toppings; and frozen waffles, pancakes, and french toast.
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•	311411 Frozen Fruit, Juice, and Vegetable Manufacturing
This U.S. industry comprises establishments primarily engaged in manufacturing
frozen fruits; frozen vegetables; and frozen fruit juices, ades, drinks, cocktail
mixes and concentrates.
•	311412 Frozen Specialty Food Manufacturing
This U.S. industry comprises establishments primarily engaged in manufacturing
frozen specialty foods (except seafood), such as frozen dinners, entrees, and side
dishes; frozen pizza; frozen whipped topping; and frozen waffles, pancakes, and
french toast.
•	31142 Fruit and Vegetable Canning, Pickling, and Drying
This industry comprises establishments primarily engaged in manufacturing
canned, pickled, and dried fruits, vegetables, and specialty foods. Establishments
in this industry may package the dried or dehydrated ingredients they make with
other purchased ingredients. Examples of products made by these establishments
are canned juices; canned baby foods; canned soups (except seafood); canned dry
beans; canned tomato-based sauces, such as catsup, salsa, chili, spaghetti,
barbeque, and tomato paste, pickles, relishes, jams and jellies, dried soup mixes
and bullions, and sauerkraut.
•	311421 Fruit and Vegetable Canning
This U.S. industry comprises establishments primarily engaged in manufacturing
canned, pickled, and brined fruits and vegetables. Examples of products made in
these establishments are canned juices; canned jams and jellies; canned tomato-
based sauces, such as catsup, salsa, chili, spaghetti, barbeque, and tomato paste;
pickles, relishes, and sauerkraut.
•	311422 Specialty Canning
This U.S. industry comprises establishments primarily engaged in manufacturing
canned specialty foods. Examples of products made in these establishments are
canned baby food, canned baked beans, canned soups (except seafood), canned
spaghetti, and other canned nationality foods.
•	311423 Dried and Dehydrated Food Manufacturing
This U.S. industry comprises establishments primarily engaged in (1) drying
(including freeze-dried) and/or dehydrating fruits, vegetables, and soup mixes and
bouillon and/or (2) drying and/or dehydrating ingredients and packaging them
with other purchased ingredients, such as rice and dry pasta.
The meat and poultry processing industry makes extensive use of anaerobic lagoons in
sequence with screening, fat traps, and dissolved air flotation when treating wastewater on site.
About one third of meat processing operations (EPA, 2002) and one fourth of poultry processing
operations (U.S. Poultry, 2006) perform on-site treatment in anaerobic lagoons.
Treatment of wastewater from fruits and vegetable processing includes screening,
coagulation/settling, and biological treatment (lagooning). The flows are frequently seasonal, and
robust treatment systems are preferred for on-site treatment. Effluent is suitable for discharge to
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the sewer. Like meat and poultry processing, this industry may also use anaerobic lagoons
(Nemerow and Dasgupta, 1991).
The food processing facilities covered by Subpart II are the same as those in the
industrial wastewater treatment sector of the Inventory. The Reporting Rule does not include the
manufacturing of food products, such as the manufacture of sugar from beets or sugar cane,
because these operations are not included in the definition of food processing.
Ethanol Production Facilities. The Inventory describes ethanol production facilities as
those that produce ethanol from the fermentation of sugar, starch, grain, or cellulosic biomass
feedstocks, or produce ethanol synthetically from petrochemical feedstocks, such as ethylene or
other chemicals. However, synthetic ethanol comprises only about 2 percent of ethanol
production (EPA, 2007).
Ethanol, or ethyl alcohol, is produced primarily for use as a fuel component, but is also
used in industrial applications and in the manufacture of beverage alcohol. Ethanol can be
produced from fermenting sugar-based feedstocks (e.g., molasses and beets), starch- or grain-
based feedstocks (e.g., corn, sorghum, and beverage waste), and cellulosic biomass feedstocks
(e.g., agricultural wastes, wood, and bagasse). Although the Department of Energy predicts
cellulosic ethanol production will increase in the coming years, it is currently only in
development in the United States. According to the Renewable Fuels Association, 82 percent of
ethanol production facilities use corn as the sole feedstock and 7 percent of facilities use a
combination of corn and another starch-based feedstock. Corn fermentation is the principal
ethanol production process in the United States and is expected to increase through 2012. (RFA,
2009).
Ethanol is produced from corn (or other starch-based feedstocks) primarily by two
methods: wet milling and dry milling. Historically, most ethanol was produced by the wet
milling process, but now the majority is produced by the dry milling process. The wastewater
generated at ethanol production facilities is handled in a variety of ways. Dry milling facilities
often combine the resulting evaporator condensate with other process wastewaters, such as
equipment wash water, scrubber water, and boiler blowdown, and treat the mixed wastewater in
anaerobic digesters. Wet milling facilities often treat their steepwater condensate in anaerobic
systems followed by aerobic polishing systems and may treat the stillage (or processed stillage)
from the ethanol fermentation/distillation process separately or together with steepwater and/or
wash water. CH4 generated in anaerobic digesters is commonly collected and either flared or
used as fuel in the ethanol production process (ERG, 2006). EPA estimates that one-third of wet
milling and three quarters of dry milling facilities treat wastewater anaerobically.
Petroleum Refineries. A petroleum refinery is any facility engaged in producing gasoline,
gasoline blending stocks, naphtha, kerosene, distillate fuel oils, residual fuel oils, lubricants, or
asphalt (bitumen) through distillation of petroleum or through redistillation, cracking, or
reforming of unfinished petroleum derivatives (40 CFR §98.250).
Many refineries use oil/water separators as a primary treatment method. These treatment
operations use gravity separation to remove oil from refinery wastewater and can emit volatile
organic compounds (VOCs). Although these VOCs are not GHGs, they convert to CO2 in the
atmosphere. Emissions from oil/water separators were included in the proposed rule but are not
included in the final because the purpose of the Reporting Rule is to collect direct GHG
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emissions data from downstream sources1 including industrial wastewater treatment. Therefore,
the rule does not require facilities to report indirect emissions such as VOCs that can convert to
CO2 once in the atmosphere. EPA expects no direct emissions of CO2 or other GHGs from these
oil/water separators. Following primary treatment, most refineries use biological treatment
systems that exhibit anaerobic conditions, resulting in CH4 production.
Other Facilities Not Covered by the Reporting Rule. Although other industrial facilities
may use anaerobic wastewater treatment processes that generate CH4, Subpart II applies only to
facilities in the four categories described above. EPA has not characterized anaerobic wastewater
treatment operations or estimated CH4 emissions in other industries. The petrochemical industry
was included in the proposed Reporting Rule, but is not included in the final rule because
petrochemical facilities are not known to use anaerobic wastewater treatment.
1 The rule requires fuel suppliers to report indirect emissions; however, downstream sources are not required to
report emissions of VOCs or other emissions that convert to C02 in the atmosphere.
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3. Emission Estimates
During the development of the Reporting Rule, EPA estimated the number of facilities in
each industry that will be required to report their industrial wastewater GHG emissions. EPA
also estimated the mass of emissions expected to be reported by each industry. For these
estimates, EPA used assumptions and methodologies developed for the Inventory.
Each industry covered by Subpart II of the Reporting Rule (40 CFR Part 98) has different
reporting requirements as outlined below:
•	Pulp and Paper: Mills are required to report their GHG emissions only if their
emissions exceed 25,000 tC02e per year in combined emissions from all
applicable source categories in the final Reporting Rule including pulp and paper
manufacturing, and, if present, stationary fuel combustion sources, industrial solid
waste landfills, industrial wastewater treatment, and any others that may apply.
•	Food Processing: Facilities are required to report their GHG emissions only if
they exceed 25,000 tC02e per year in combined emissions from all applicable
source categories, including, but not limited to stationary fuel combustion
sources, industrial solid waste landfills, and industrial wastewater treatment.
Process emissions are not included in determining the threshold, nor are facilities
required to report process emissions.
•	Ethanol Production: Facilities are required to report their GHG emissions only if
they exceed 25,000 tC02e per year in combined emissions from all applicable
source categories, including, but not limited to stationary fuel combustion
sources, industrial solid waste landfills, and industrial wastewater treatment.
Process emissions are not included in determining the threshold, nor are facilities
required to report process emissions.
•	Petroleum Refining: All petroleum refineries are required to report their GHG
emissions. Refineries must report emissions from their refinery operations and, if
present, from stationary fuel combustion sources, industrial solid waste landfills,
industrial wastewater treatment, and any other applicable source categories.
The procedures EPA used to estimate the number of facilities required to report and their
industrial wastewater treatment GHG emissions are described in the following subsections.
3.1 Pulp and Paper Mills
EPA estimated that there are 565 pulp and paper mills in the United States (EPA, 1993).
Using assumptions presented in the Inventory, EPA estimated that 25 percent (141) of these mills
have anaerobic secondary treatment and would be required to report their industrial wastewater
treatment CH4 emissions. EPA does not know the production or emissions from these mills, but
assumed that all facilities with anaerobic wastewater treatment would have total facility
emissions that exceed the 25,000 metric tons of C02e per year reporting threshold.
To estimate CH4 emissions from industrial wastewater treatment at pulp and paper mills,
EPA used the methodology presented in the Inventory, which is summarized in Equation 3-1:
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C02e= F x p x w x BOD x cf x TA x Bo x MCF x GWP
(3-1)
where:
C02e
= C02 equivalent of methane emissions for facilities required to report

(tC02e).
F
= Estimated fraction of facilities required to report (decimal).
P
= Total industry production (thousand metric ton/year).
W
= Wastewater outflow (m3/metric ton).
BOD
= Organic matter concentration in untreated wastewater, measured as BOD5

(kg/m3).
cf
= Factor for conversion of BOD to COD (unitless)
TA
= Fraction of wastewater BOD treated anaerobically in secondary treatment

(decimal).
Bo
= Maximum CH4-producing capacity (kg CH4/kg COD).
MCF
= Methane conversion factor for anaerobic treatment.
GWP
= Global warming potential for CH4.
EPA estimated that pulp and paper industrial wastewater treatment emissions amount to
4,075,044 tC02e, using the values listed in Table 3-1.
Table 3-1. Values Used to Estimate Pulp and Paper CH4 Emissions
Variable
Parameter
Value
Sou ree
F
Estimated fraction of facilities required to
report (decimal)
0.25
ERG, 2008
P
Total industry production (thousand metric
tons/year)
135,889
EPA, 2010
W
Wastewater outflow (m3/ton)
85
World Bank, 1999
Nemerow andDasgupta, 1991
BOD
Organic matter concentration in untreated
pulp and paper mill wastewater, as BOD5
(kg/m3)
0.4
EPA, 1997b
EPA, 1993
World Bank, 1999
cf
Factor for conversion of BOD to COD,
specific to pulp and paper mill wastewater
(kg COD/kg BOD)
2
EPA, 1997a
TA
Fraction of pulp and paper industry
wastewater BOD treated in secondary
treatment
0.42
EPA, 2010
Bo
Maximum CH4-producing capacity (kg
CH4/kg COD)
0.25
IPCC, 2006
MCF
Methane conversion factor for anaerobic
systems
0.8
IPCC, 2006
GWP
Global warming potential
21
EPA, 2010
3.2 Food Processing Facilities
Food processing facilities covered by Subpart II fall into three segments: fruits and
vegetables processing, meat processing, and poultry processing. EPA's estimates of the number
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of facilities in each segment required to report and their industrial wastewater treatment CH4
emissions are discussed below.
Fruits and vegetables processing. Based on information from the 2002 U.S. Economic
Census for Manufacturing (U.S. Census Bureau, 2002), EPA estimated that there are 1,746 fruits
and vegetable processing facilities in the United States. Using assumptions presented in the
Inventory, EPA estimated that 5 to 6 percent (100) of these facilities have anaerobic secondary
treatment resulting in emissions of 123,000 tC02e. Thus, for 100 facilities, the average emissions
are 1,230 tC02e per plant per year. Because this estimate is far below the 25,000 tC02e per year
threshold for reporting, EPA estimated that no fruits and vegetables processing facility would be
required to report its industrial wastewater treatment GHG emissions.
Meat processing. Meat processing facilities are required to report their GHG emissions if
they exceed 25,000 tC02e per year in combined emissions from stationary fuel combustion
sources, industrial solid waste landfills, and industrial wastewater treatment. EPA estimated the
number of meat processing facilities that would be required to report GHG emissions based on
emissions from industrial wastewater treatment only. EPA ignored the other sources because it
had no information about emissions from stationary fuel combustion sources or industrial solid
waste landfills at meat processing facilities.
EPA had no data on meat production or GHG emissions per plant. As a result, to estimate
the number of meat processing facilities that would emit more than 25,000 tC02e per year from
industrial wastewater treatment processes, EPA back-calculated the production rate that would
result in emissions of 25,000 tC02e using Equation 3-2.
P = t/(W x BOD x cf x Bo x MCF x GWP) x 1,000 kg/ton	(3-2)
where:
P	= Production resulting in GHG emissions above the reporting threshold
(ton/year).
W	= Wastewater outflow (m3/ton).
BOD = Organic matter concentration in the wastewater, measured as BOD, kg/m3.
cf	= Factor for conversion of BOD to COD (unitless)
B0	= Maximum CH4-producing capacity (kg CH4/kg COD).
MCF = Methane conversion factor (decimal).
GWP = Global warming potential.
t	= Reporting threshold (25,000 tC02e/yr).
Using the values listed in Table 3-2. EPA estimated that 133,000 metric tons/year of meat
production would result in industrial wastewater treatment CH4 emissions that would reach the
25,000 t C02e reporting threshold.
EPA had collected limited production information when it established national effluent
limitation guidelines and standards for this industry in 2004 (EPA, 2004a). At that time, EPA
estimated that there were 139 meat processors that processed more than 50 million pounds
(22,700 metric tons) per year. For the purpose of this estimate, EPA assumed that 40 facilities
processed more than 133,000 tons/year, the tonnage that reaches the reporting threshold. EPA
estimates that 33 percent of meat processing facilities have on-site anaerobic treatment. Thus,
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EPA estimated that 13 meat processing facilities would be required to report their industrial
wastewater treatment CH4 emissions and that none of these facilities recover biogas.
Table 3-2. Values Used to Estimate Meat and Poultry Processing CH4 Emissions
\ iiriiihk*
P;ir;imclcr
Mc.il Processing
Poulln Processing
Source
W
Wastewater outflow (m3/ton)
5.3
12.5
ARCADIS, 2004
EPA, 2004a
BOD
Organic matter concentration in the
wastewater, measured as BOD (kg/m3)
2.822
1.508
EPA, 2002
ARCADIS, 2004
cf
Factor for conversion of BOD to
COD, specific to meat and poultry
processing wastewater (kg COD/kg
BOD)
3
3
EPA, 1997a
Bo
Maximum CH4-producing capacity
(kg CH4/kg COD)
0.25
0.25
IPCC, 2006
MCF
Methane conversion factor
0.8
0.8
IPCC, 2006
GWP
Global warming potential
21
21
EPA, 2010
EPA estimated these 13 meat processing facilities each emit 25,000 tC02e per year, for a
total of 325,000 tC02e.
Poultry processing. Like meat processing facilities, poultry processing facilities are
required to report if their combined emissions from stationary fuel combustion sources, industrial
solid waste landfills, and industrial wastewater treatment exceed the threshold. As with meat
processing, EPA had no data on per plant poultry production or per plant GHG emissions. Again,
EPA back-calculated the production rate that would result in emissions of 25,000 tC02e using
Equation 3-2.
Using the values listed in Table 3-2, EPA estimated that 105,000 metric tons/year) of
poultry production would result in industrial wastewater treatment CH4 emissions that would
reach the 25,000 tCC^e reporting threshold.
EPA had limited production information collected when it established national effluent
limitation guidelines and standards for this industry in 2004 (EPA, 2004a). At that time, EPA
estimated that there were 206 poultry processors that processed more than 100 million pounds
(45,400 metric tons) per year. For the purpose of this estimate, EPA assumed that any of these
206 facilities that used anaerobic wastewater treatment processes would be required to report
their GHG emissions. EPA estimates that 25 percent of the 206 poultry processing facilities that
process more than 100 million pounds per year have on-site anaerobic treatment. Thus, EPA
estimated that 50 poultry processing facilities would be required to report their industrial
wastewater treatment GHG emissions.
EPA estimated these 50 poultry processing facilities each emit 25,000 tCC^e per year, for
a total of 1,250,000 tC02e.
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3.3 Ethanol Production Facilities
Ethanol production facilities are required to report their GHG emissions if they exceed
25,000 tCC^e per year in combined emissions from all applicable source categories, including,
but not limited to stationary fuel combustion sources, industrial solid waste landfills, and
industrial wastewater treatment. EPA estimated the number of ethanol production facilities that
would be required to report GHG emissions based on emissions from industrial wastewater
treatment only. For estimates of coverage based on combined emissions, see the TSD for Ethanol
Production.
Based on information from the Renewable Fuels Association (RFA, 2009), EPA
estimated that there are 170 ethanol production facilities in the United States. Of these, EPA
estimated that 85 percent use dry milling and 15 percent use wet milling (EPA, 2007). Using
production information provided in the RFA data and parameter values listed in Table 3-3, EPA
estimated CH4 emissions from industrial wastewater treatment at each ethanol production facility
using methodology presented in the Inventory and summarized in Equation 3-1.
Table 3-3. Values Used to Estimate Ethanol Production CH4 Emissions
Variable
Parameter
Wet Milling
Value
Dry Milling
Value
Sou ree
F
Facilities with anaerobic treatment
(decimal)
1
0.33
ERG, 2008
P
Total industry production (million
gallons/year)
1,494
5,006
EPA, 2010
W
Wastewater outflow (gal/gal ethanol)
10
1.25
Donovan, 1996
NRBP, 2001
Ruocco, 2006a
Ruocco, 2006b
Merrick, 1998
BOD
COD or BOD (kg/m3)
BOD = 1.5
COD = 3
Ruocco, 2006a
Ruocco, 2006a
Merrick, 1998
White and Johnson, 2003
cf
Factor for conversion of BOD to
COD, specific to ethanol production
wastewater (kg COD/kg BOD)
2
2
EPA, 1997a
Bo
Maximum CH4-producing capacity
(kg CH4/kg COD)
0.25
0.25
IPCC, 2006
MCF
Methane conversion factor
0.8
0.8
IPCC, 2006
GWP
Global warming potential
21
21
EPA, 2010
TA
Fraction of industry wastewater BOD
treated in secondary treatment
0.75
0.333
EPA, 2010
EPA determined that 12 facilities that use wet milling operations had sufficient
production to exceed the 25,000 tC02e reporting threshold. However, only one-third of facilities
that use wet milling are expected to use anaerobic treatment (ERG, 2008). Therefore, EPA
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estimated that four facilities with wet milling operations will be required to report GHG
emissions (based on emissions from industrial wastewater treatment only).
EPA assumed that all facilities that use dry milling operations had anaerobic treatment in
place and none operated a biomethanator2. In keeping with the Inventory estimation
methodology, EPA assumed that 75 percent of the facilities recovered biogas from their
anaerobic treatment processes. EPA estimated that no ethanol production facilities that use dry
milling operations would meet the reporting threshold based on emissions from industrial
wastewater treatment only.
3.4 Petroleum Refineries
All petroleum refineries are required to report their GHG emissions. Refineries must
report emissions from their refining operations and, if present, from stationary fuel combustion
sources, industrial solid waste landfills, and industrial wastewater treatment.
Based on information from the Energy Information Administration (EIA, 2009), EPA
determined that there are 150 petroleum refineries in the United States. Using assumptions
presented in 2007 Inventory, EPA estimated that 100 percent of the refineries use wastewater
treatment that exhibits anaerobic conditions, and thus they would be required to report their
industrial wastewater treatment CH4 emissions. Using production information from EIA (EIA,
2009) and parameter values listed in Table 3-4, EPA estimated CH4 emissions from industrial
wastewater treatment for petroleum refineries using methodology presented in the Inventory, as
summarized in Equation 3-1.
Table 3-4. Values Used to Estimate Petroleum Refinery CH4 Emissions
Variable
Parameter
Value
Source
F
Facilities with anaerobic treatment (decimal)
1
ERG, 2008
P
Total industry production (thousand barrels/year)
6,567,929
EPA, 2010
W
Wastewater outflow (gal/barrel produced)
35
CARB, 2007
Timm, 1985
COD
COD (kg/m3)
0.45
Benyahia el al (2006)
Bo
Maximum CH4-producing capacity (kg CH4/kg COD)
0.25
IPCC, 2006
MCF
Methane conversion factor
0.3 a
IPCC, 2006
GWP
Global warming potential
21
EPA, 2010
TA
Fraction of industry wastewater BOD treated in
secondary treatment
1
EPA, 2010
a - EPA assumes refineries operate trickling filters, rotating biological contactors, or other systems that exhibit
anaerobic conditions. Therefore, EPA selected a CH4 conversion factor of 0.3 for these treatment systems.
EPA assumed that no petroleum refineries recover biogas and estimated that petroleum
refinery industrial wastewater treatment emissions amount to 616,674 (tCC^e) per year (EPA,
2007).
2 A biomethanator is a specific type of anaerobic reactor, treating a higher fraction of industry wastewater BOD than
is typically treated in secondary treatment.
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3.5 Summary
Table 3-5 summarizes the number of plants EPA estimates will be required to report
under the Reporting Rule and their estimated emissions. These estimates were used to calculate
estimated cost of compliance, which can be found in Greenhouse Gas Reporting Rule, Industrial
Wastewater Treatments Source Category, Costs for Final Rule Monitoring Requirements -
Revised (ERG, 2010).
Table 3-5. Estimated Number of Plants Required to Report and Estimated Emissions
Category
No. of
Plants in
the U.S.
Estimated Plants with
Anaerobic Treatment
Estimated
No. of Plants
Required to
Report
Estimated No.
of Reporting
Plants with
CH4 Recovery
Estimated
Emissions Plants
are Required to
Report (tC02c)
Pulp and Paper
565
25%
141
0
4,075,044
Fruits and Vegetables
Processing
1,746
100% have anaerobic
treatment, but none (0)
exceed reporting
threshold
0
0
123,000
Meat Processing
3,337
33% have anaerobic
treatment, but EPA
estimates only 13 exceed
the reporting threshold
13
0
0
Poultry Processing
536
25% have anaerobic
treatment, but EPA
estimates not more than
50 exceed the reporting
threshold
50
0
1,250,000
Ethanol Production -
wet mill
15% of 170 mills
25
33% have anaerobic
treatment; of those
plants, half have enough
production to exceed the
reporting threshold
4
4
21,681
Ethanol Production -
dry mill
85% of 170 mills
145
100% but none exceed
reporting threshold
based solely on
wastewater treatment
0
0
0
Petroleum Refineries
150
100%
150
0
616,674
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4. Estimating Methane Generation from Wastewater Treatment
CH4 emissions from industrial wastewater treatment are a function of the concentration of
soluble organic material in anaerobically treated wastewater and an emission factor that
characterizes the extent to which waste becomes CH4 (IPCC, 2006). The emission factor is the
product of the maximum CH4 producing capacity of the wastewater (B0) and the methane
conversion factor (MCF) that accounts for the ability of the particular system to achieve that
maximum CH4 production. The 2006 IPCC Guidelines for National Greenhouse Gas Inventories,
Volume 5, Chapter 6, p.6.2.1, provide values of B0 for organic material measured as COD and as
BOD (see Table 4-1).
Most wastewater treatment systems will not produce the maximum amount of CH4
possible because the conditions in the systems are not ideal for CFLi production. The CH4
producing potential of a specific system is represented by a parameter known as the CH4
conversion factor (MCF). This value ranges from 0 to 100 percent and reflects the capability of a
system to produce the maximum achievable CH4 based on the organic matter present in the
wastewater. A higher MCF equates to a higher CH4 production. MCF values for various types of
treatment systems are presented in the 2006 IPCC Guidelines for National Greenhouse Gas
Inventories, Volume 5, Chapter 6, Table 6.8. The MCFs used in the Reporting Rule are listed in
Table 4-1.
Using the emission factors in Table 4-1 and measured concentrations of organic matter
and flow rates, facilities covered under the Reporting Rule are required to estimate the annual
mass of CH4 they generate from their anaerobic wastewater treatment processes3. Facilities must
measure both the wastewater flow and the concentration of organic material entering anaerobic
wastewater treatment processes (specifically anaerobic reactors and anaerobic lagoons) for this
calculation, as shown in Figure 4-1.
Primary Wastewater
Treatment
Anaerobic Wastewater
Treatment
Raw
Wastewater
Flow and COD or BOD
Measurement Location
CH4 Generated
Treated
Wastewater
Figure 4-1. Methane Generation
3 Operators of anaerobic sludge digesters are not required to report CH4 generated. Anaerobic sludge digesters are designed to
recover CH4 and not emit CH4 directly from the digester apparatus. Operators of anaerobic sludge digesters are required to report
the amount of CH4 recovered and emitted from the recovery system. See Sections 5 and 6 of this document for these
requirements.
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To reduce the reporting burden, the Reporting Rule allows facilities to use COD in
conjunction with Equation 4-1 or 5-day biochemical oxygen demand (BOD5) with Equation 4-2
to calculate CH4 generation. If facilities measure COD, they should estimate the annual mass of
CH4 generated by each anaerobic wastewater treatment process they operate, using Equation 4-1:
52
ch4g=]T[fi OW„ X CODw x Bo x MCF x 0.001 ]	(4-1)
w=l
where:
CH4G = Annual mass CH4 generated from the anaerobic wastewater treatment
process (metric tons).
Flown = Volume of wastewater sent to an anaerobic wastewater treatment process
in week n (m3/week).
CODn = Average weekly concentration of COD of wastewater entering an
anaerobic wastewater treatment process (for month n)(kg/m3).
B0	= Maximum CH4 producing potential of wastewater (kg CH4/kg COD), use
the value 0.25.
MCF = CH4 conversion factor, based on relevant values in Table 3-2.
0.001 = Conversion factor from kg to metric tons.
w	= Index for weekly measurement period.
If facilities measure BOD5, they should estimate the annual mass of CH4 generated by
each anaerobic wastewater treatment process they operate, using Equation 4-2:
52 r	i
CH4G = ^[Floww x BOD5 w x Bo x MCF x 0.001 J	(4-2)
w=l
where:
CH4G = Annual mass of CH4 generated from the anaerobic wastewater treatment
process (metric tons).
Flown = Volume of wastewater sent to an anaerobic wastewater treatment process
in week n (m3/week).
BOD5n = Average weekly concentration of 5-day BOD of wastewater entering an
anaerobic wastewater treatment process for month n (kg/m3).
B0	= Maximum CH4 producing potential of wastewater (kg CH4 /kg BOD5), use
the value 0.6.
MCF = CH4 conversion factor, based on relevant values in Table 3-2.
0.001 = Conversion factor from kg to metric tons.
w	= Index for weekly measurement period.
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Table 4-1. Emission Factors
Factors
Default Value
U nits
B0 - for facilities monitoring COD
0.25
kg CHz/kg COD
B0 - for facilities monitoring BOD5
0.60
kg CHVkg BOD5
MCF - anaerobic reactor (e.g., upflow anaerobic sludge blanket, fixed film)
0.8
Fraction
MCF - anaerobic deep lagoon (depth more than 2 m)
0.8
Fraction
MCF - anaerobic shallow lagoon (depth less than 2 m)
0.2
Fraction
To determine CH4 generation using Equations 4-1 or 4-2, facilities are required to
measure both flow and either the COD or BOD5 concentration of wastewater entering the
anaerobic wastewater treatment process once each calendar week that the process is operating,
with at least three days between measurements. Facilities must collect samples representing
wastewater influent to the anaerobic wastewater treatment process, following all preliminary and
primary treatment steps, as shown in Figure 4-1.
4.1 Flow Measurement
Flow can be measured with hydraulic structures such as flumes and weirs that are
inserted in open channel flow (flow in conduits that are not full). Flow can also be measured with
meters (e.g., electromagnetic, Venturi, ultrasonic) that are appropriate for closed channel flow
(flow in a liquid-full conduit). Facilities must measure the flow rate for the 24-hour period for
which they collect samples analyzed for COD or BOD5 concentration. Also, the flow
measurement location must correspond to the location used to collect samples analyzed for the
COD or BOD5 concentration.
Facilities may measure flow rate using one of the methods specified below:
•	ASME MFC-3M-2004 Measurement of Fluid Flow in Pipes Using Orifice,
Nozzle, and Venturi;
•	ASME MFC-5M-1985 (Reaffirmed 1994) Measurement of Liquid Flow in
Closed Conduits Using Transit-Time Ultrasonic Flowmeters;
•	ASME MFC-16-2007 Measurement of Liquid Flow in Closed Conduits with
Electromagnetic Flowmeters;
•	ASTM D1941 - 91(2007) Standard Test Method for Open Channel Flow
Measurement of Water with the Parshall Flume; or
•	ASTM D5614 - 94(2008) Standard Test Method for Open Channel Flow
Measurement of Water with Broad-Crested Weirs.
A facility may choose another method of measurement other than those listed above;
however, they must follow the manufacturer's instructions for the wastewater flow measurement
device.
Any chosen flow measurement system must measure the entire discharge flow; it must be
accurate and in working order, calibrated, and maintained. Facilities are required to calibrate all
wastewater flow measurement devices prior to the first year of reporting and recalibrate them
either biennially (every 2 years) or at the minimum frequency specified by the manufacturer.
Wastewater flow measurement devices must be calibrated using the procedures specified by the
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device manufacturer. For more information on flow measurement see the NPDES Compliance
Inspection Manual, Appendix O (U.S. EPA, 2004a).
4.2 Organic Matter Concentration Measurement and Analysis
To calculate CH4 generation, in addition to wastewater flow, facilities are also required to
measure organic matter concentration in the form of either BOD5 or COD. Facilities must collect
samples representative of the wastewater entering their anaerobic treatment systems. Wastewater
typically flows through a pipe or a conduit and both the flow rate and the concentration of
organic material in the wastewater varies over time. For example, wastewater may be discharged
intermittently after batch food processing operations, resulting in spikes of flow and pollutant
load into the anaerobic wastewater treatment system.
Wastewater samples are collected in three ways:
•	Grab sample: single samples collected at one time and place. Grab samples are
representative when the sampled stream does not vary in concentration over time.
•	Time-weighted composite sample: equal volume discrete sample aliquots
collected at constant time intervals into one container. A time-weighted composite
sample can be collected either manually or with an automatic sampler. Time-
weighted composites are representative of the sampled stream when the flow rate
does not vary over time.
•	Flow- proportional sample: equal volume discrete sample aliquots collected after
a fixed stream flow intervals into one container. This can be achieved by:
—	Collecting a constant sample volume at varying time intervals proportional
to the wastewater flow; or
—	Collecting a volume of each individual aliquot proportional to the flow,
while maintaining a constant time interval between the aliquots.
Flow proportional samples can be collected with an automatic sampler and a compatible
flow measuring device, with a flow chart and an automatic sampler capable of collecting discrete
samples, or manually by compositing individual grab samples by volume versus flow chart
readings.
EPA considered allowing facilities to collect grab samples if the wastewater influent to
the anaerobic wastewater treatment process represents the discharge from a well-mixed
wastewater storage unit (tank or pond), such that the COD or BOD5 concentration of the waste
stream does not vary in a 24-hour period. EPA also considered allowing facilities to collect time-
weighted composite samples if the flow rate of the wastewater influent to the anaerobic
wastewater treatment process does not vary more than ±50 percent of the mean flow rate for a
24-hour sampling period.
However, establishing that the sampled stream meets the conditions necessary for these
types of sampling would require the facility to collect additional samples. For this reason, the
final Reporting Rule requires facilities to collect a flow-proportional composite sample. The
Reporting Rule requires either a constant time interval between samples, keeping sample volume
proportional to stream flow, or a constant sample volume with the time interval between samples
4-4

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proportional to stream flow. The sample must represent the average COD or BOD5 concentration
of the waste stream over a 24-hour sampling period at a location similar to that specified in
Figure 4-1.
Facilities are required to collect a minimum of four samples per 24-hour period, which
should be combined for analysis. The requirement of the final Reporting Rule ensures that the
collected sample represents the wastewater influent to the anaerobic wastewater treatment
process, without imposing an unnecessary burden on reporters. For more information on
sampling, see the NPDESPermit Writer'sManual (U.S. EPA, 1996) and the NPDES
Compliance Inspection Manual (U.S. EPA, 2004b).
Facilities must determine the organic matter concentration in wastewater treated
anaerobically using analytical methods for COD or BOD5 specified in 40 CFR part 136.3
Table IB. When determining concentrations of wastewater influent to the anaerobic wastewater
treatment process to calculate CH4 generated, samples may be diluted to the concentration range
of the approved method. The concentration of the diluted sample must be multiplied by the
dilution factor to determine the concentration of the undiluted sample. The undiluted sample
concentration is used to calculate CH4 generation.
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5. Estimates of Methane Recovery
"Biogas" refers to the combination of C02, CH4, and other gases produced by the
biological breakdown of organic matter in the absence of oxygen. Some facilities recover some
or all of the biogas generated by anaerobic wastewater treatment and anaerobic sludge digestion
and route the recovered biogas to a destruction device. These devices include flares, thermal
oxidizers, boilers, turbines, internal combustion engines, or any other combustion units used to
destroy or oxidize CH4 contained in the biogas. Figure 5-1 depicts biogas recovery from
anaerobic wastewater treatment.
Primary Treatment
Anaerobic Wastewater
Treatment Operations
Biogas Destruction
Device
Raw
Wastewater
Solids to
Disposal
Solids
Solids
Biogas CH.
Recovery
Treated
Wastewater
Figure 5-1. Diagram of Biogas Recovery from Anaerobic Wastewater Treatment
Facilities that use aerobic processes to treat wastewater generate larger quantities of
waste sludge and may use anaerobic digestion to reduce the volume of sludge and recover the
biogas. Figure 5-2 depicts biogas recovery from anaerobic sludge digestion.
5-1

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Treated
Wastewater
Raw
Wastewater
Solids
Solids
Solids to
Disposal
Biogas (CH4) Recovery
Primary Treatment
Aerobic Wastewater
Treatment Operations
Anaerobic Sludge
Digestion
Biogas Destruction
Device
Figure 5-2. Diagram of Biogas Recovery from Anaerobic Sludge Digestion
Subpart II of the Reporting Rule requires facilities to calculate and report the amount of
CH4 they recover. They must calculate CH4 recovery using Equation 5-1.
M
R=	x CF1	(5-'>
m=l
where:
R	= Annual quantity of CH4 recovered from anaerobic reactor, digester, or
lagoon (metric tons CH4/yr).
M	= Total number of measurement periods in a year. Use M=365 (M=366 for
leap years) for daily averaging of continuous monitoring. Use M=52 for
weekly sampling.
m	= Index for measurement period.
Vm	= Cumulative volumetric flow for the measurement period in actual cubic
feet (acf). If no biogas was recovered during a monitoring period, use
zero.
(CCH4)m = Average CH4 concentration of biogas during the measurement period,
(volume %).
CF	= Correction factors for temperature, pressure, and/or moisture, if necessary.
For Equation 5-1, facilities must determine the volume of gas recovered during a
monitoring period and the CH4 concentration of the gas. These measured values may be
multiplied by a number of correction factors:
•	Volumetric moisture correction term for the measurement period, based on the
average moisture content of biogas during the measurement period;
•	Temperature at which flow is measured for the measurement period; and
•	Pressure at which flow is measured for the measurement period.
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If a facility continuously monitors the CH4 concentration and these correction factors
using a meter specifically for CH4 gas, they must use this system to calculate CH4 recovery. A
fully integrated system that directly reports CH4 content only requires the facility to sum the
results of all monitoring periods for a given year.
5.1	Biogas Flow Measurement
To estimate the annual mass of CH4 recovered, facilities are required to continuously
monitor the recovered biogas flow rate. Every facility with biogas recovery from anaerobic
wastewater treatment operations must use a gas flow meter capable of continuously measuring
the volumetric flow rate of the recovered biogas. Facilities may measure flow rate using one of
the methods specified below:
•	ASME MFC-3M-2004, Measurement of Fluid Flow in Pipes Using Orifice,
Nozzle, and Venturi;
•	ASME MFC-4M-1986 (Reaffirmed 1997), Measurement of Gas Flow by Turbine
Meters;
•	ASME MFC-6M-1998, Measurement of Fluid Flow in Pipes Using Vortex
Flowmeters;
•	ASME MFC-7M-1987 (Reaffirmed 1992), Measurement of Gas Flow by Means
of Critical Flow Venturi Nozzles;
•	ASME MFC-11M-2006 Measurement of Fluid Flow by Means of Coriolis Mass
Flowmeters;
•	ASME MFC-14M-2003 Measurement of Fluid Flow Using Small Bore Precision
Orifice Meters; or
•	ASME MFC-18M-2001 Measurement of Fluid Flow using Variable Area Meters;
or
•	Method 2A or 2D at 40 CFR part 60, appendix A-l.
A facility may measure biogas flow using a method other than those listed above;
however, they must follow the manufacturer's instructions for the gas flow measurement device.
Each gas flow meter must be calibrated every two years or at the minimum frequency specified
by the manufacturer.
A facility is required to determine temperature and pressure of the biogas weekly only if
its gas flow meter is not equipped with automatic correction for temperature, pressure, or, if
necessary, moisture content. A facility must measure moisture content weekly if the CH4
concentration is determined on a dry basis and biogas flow is determined on a wet basis, or vice-
versa, and the flow meter does not automatically correct for moisture content. All temperature,
pressure, and moisture content monitors must be calibrated using the procedures and frequencies
specified by the device manufacturer. If the device manufacture does not provide calibration
specifications, facilities may use an industry accepted or industry standard practice. All
equipment must be maintained to the manufacturer's specifications.
5.2	Biogas Composition Monitoring
The Reporting Rule allows either continuous or weekly monitoring of the biogas CH4
concentration. If a facility has equipment that continuously monitors the CH4 concentration, the
facility must use it. If a facility is not currently monitoring the biogas CH4 concentration, they
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must use either installed or portable equipment to monitor it weekly. Weekly monitoring
provides an adequate number of samples to evaluate the variability and uncertainly associated
with CH4 generation.
Facilities with biogas recovery from anaerobic processes must measure gas composition
with a monitor capable of measuring the concentration of CH4 in the recovered biogas using
either one of the methods specified below or as specified by the device manufacturer if they use
another device. The gas composition monitors must be calibrated prior to the first reporting year
and recalibrated either annually or at the minimum frequency specified by the manufacturer,
whichever is more frequent.
•	Method 18 at 40 CFR part 60, Appendix A-6;
•	ASTM D1945-03, Standard Test Method for Analysis of Natural Gas by Gas
Chromatography;
•	ASTM D1946-90 (Reapproved 2006), Standard Practice for Analysis of
Reformed Gas by Gas Chromatography;
•	GPA Standard 2261-00, Analysis for Natural Gas and Similar Gaseous Mixtures
by Gas Chromatography;
•	UOP539-97 Refinery Gas Analysis by Gas Chromatography; or
•	As an alternative to the gas chromatography methods, a facility may use total
gaseous organic concentration analyzers and calculate the CH4 concentration.
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6. Methane Emissions Calculation
In addition to reporting CH4 generation, facilities must report the amount of CH4 emitted
to the atmosphere. For facilities that do not recover biogas, total emissions equal the CH4
generation of each anaerobic reactor or lagoon and can be estimated using Equation 6-1.
CH4E = CH4G	(6-1)
where:
CH4E = Annual mass of CH4 emissions from the wastewater treatment process
(metric tons).
CH4G = Annual mass of CH4 generated from the wastewater treatment process, as
calculated in Equations 3-1 or 3-2 (metric tons).
Leakage. Facilities that recover biogas from either anaerobic wastewater treatment
operations or sludge digesters must take into account the inefficiency of the recovery process as
depicted in Figure 6-1. Leakage refers to the annual mass of CH4 that is generated but not
recovered.
Treated
Wastewater
Raw
Wastewater
Solids
~ CH4 Leakage
Solids
Solids to
Disposal
Biogas (CH4)
Recovery
CH4 Leakage
Biogas (CH4) Recovery ]
Anaerobic Sludge
Digestion
Primary Treatment
Anaerobic Wastewater
Treatment Operations
Biogas Destruction
Device
Figure 6-1. Diagram of Leakage From Anaerobic Sludge Digestion Biogas Recovery
For anaerobic processes with biogas recovery, facilities must calculate leakage using
Equation 6-2 by multiplying recovery (calculated using Equation 5-1) by a collection efficiency
factor in Table 6-1. This allows facilities to quantify the amount of CH4 that is not captured by
their destruction device.
CH4L = R x f~r ~ ll	(6-2)
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where:
CH4L = Leakage at the anaerobic process (metric tons CH4).
R	= Annual quantity of CH4 recovered from anaerobic reactor, anaerobic
lagoon, or anaerobic digester, as calculated in Equation 5-1 (metric tons
CH4).
CE	= CH4 collection efficiency of anaerobic process, as specified in Table 6-1
(decimal).
Table 6-1. Collection Efficiencies of Anaerobic Processes
Anaerobic Process Type
Cover Tvpc
Methane Collection Efficiency
Covered anaerobic lagoon (biogas capture)
Bank to bank, impermeable
0.975
Modular, impermeable
0.70
Anaerobic sludge digester; anaerobic reactor
Enclosed vessel
0.99
Destruction Efficiency. Biogas destruction devices, such as flares, thermal oxidizers,
boilers, turbines, internal combustion engines, and other combustion units destroy or oxidize
CH4 contained in the biogas, producing CO2 and water. However, biogas destruction devices
operate with less than 100 percent efficiency. This means the device exhaust gases will contain
some CH4. At facilities with biogas recovery, reported total emissions must take into account the
destruction of CH4 by these recovery devices. These facilities' total annual mass of CH4
emissions are equal to their leakage rate plus their total recovery multiplied by the recovery
device CH4 destruction efficiency (DE). Total emissions equal the quantity that leaks from the
anaerobic process plus the quantity not destroyed in the destruction device, as shown in
Equation 6-3.
CH4E = CH4L + R (1 - DE)	(6-3)
where:
ch4e
ch4l
R
DE
Annual quantity of CH4 emitted (metric tons/yr).
Leakage at the anaerobic process, as calculated in Equation 6-2 (metric
tons CH4).
Annual quantity of CH4 recovered from the anaerobic reactor digester, or
lagoon, as calculated in Equation 5-1 (metric tons CH4).
Destruction efficiency (i.e., the fraction of CH4 destroyed in the
destruction device (decimal)).
Destruction devices may be operated less than continuously. Also, a facility may operate
more than one destruction device (e.g., they may operate a primary destruction device and a
backup). Total emissions for facilities with biogas destruction devices must be estimated using
Equation 6-4.
CH4E = CH4L + R (1 - (DE,/fl)esl ,)) + R (1 - (DE2 x FDest 2))	(6-4)
where:
CH4E = Annual quantity of CH4 emitted (metric tons/yr).
CH4L = Leakage at the anaerobic process, as calculated in Equation 6-2 (metric
tons CH4).
6-2

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Annual quantity of CH4 recovered from the anaerobic reactor, digester, or
lagoon, as calculated in Equation 5-1 (metric tons CH4).
Primary destruction device CH4 destruction efficiency (lesser of
manufacturer's specified destruction efficiency and 0.99). If the gas is
transported off-site for destruction, use DE=1.
Fraction of hours the primary destruction device was operating (device
operating hours/8760 hours per year). If the gas is transported off-site for
destruction, use fDest=l-
Back-up destruction device CH4 destruction efficiency (lesser of
manufacturer's specified destruction efficiency and 0.99).
Fraction of hours the back-up destruction device was operating (device
operating hours/8760 hours per year).

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7. Costs for GHG Reporting
The Reporting Rule requires operators to monitor their CH4 -generating processes by
measuring the amount of wastewater entering the anaerobic treatment process, the concentration
of organic material in the wastewater prior to treatment, the volume of biogas recovered, and the
concentration of CH4 in the recovered biogas. To determine costs of the required monitoring,
EPA evaluated whether facilities are currently conducting this monitoring. For monitoring that is
not routinely conducted, EPA estimated the costs that a typical facility would incur to meet the
requirement.
The estimates include one-time capital costs to purchase and install monitoring devices
and recurring annual costs for analytical services, supplies, and labor. Table 7-1 summarizes the
total costs EPA estimates will be incurred by facilities in each industry covered by Subpart II.
EPA estimated that these monitoring requirements would cost, on average, $4,083 per year per
facility (total annualized costs) or $1.4 million for the 358 facilities estimated to incur
monitoring costs. For more information on the estimated costs of reporting for this Subpart,
please see found in Greenhouse Gas Reporting Rule, Industrial Wastewater Treatments Source
Category, Costs for Final Rule Monitoring Requirements - Revised (ERG, 2010).
7-1

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Table 7-1. Industrial Wastewater Treatment Monitoring Costs
Category
No. of
Plants
Required
to Report
%Plants
with
Anaerobic
Treatment
No. of
Plants
with
Anaerobic
Treatment
No. of
Plants
with CH4
Recovery
National (Scalcd-Up) Estimated Costs
National (Scalcd-Up) Estimated Costs
National (Scalcd-
Up) Estimated
Costs
WW
Monitoring
Costs -Cap
WW
Monitoring
Costs -
Annualized
Cap
WW
Monitoring
Costs -
Annual
WW
Monitoring
Costs -TAC
ch4
Recovery
Monitoring
Costs -Cap
CH,
Recovery
Monitoring
Costs -
Annualized
Cap
ch4
Recovery
Monitoring
Costs -
Annual
CH,
Recovery
Monitoring
Costs -
TAC
Total
(WW+CH4
recovery)
Monitoring TAC
Pulp and Paper
565
25%
141
0
$1,428,843
$134,873
$463,300
$598,173
0
$0
$0
$0.00
$598,173
Food Processing
63
100%
63
0
$455,805
$43,025
$206,640
$249,665
$0
$0
$0
$0.00
$249,665
Ethanol
Production - wet
mill
15% of 170 mills
4
100%
4
4
$17,064
$1,611
$13,120
$14,731
$23,600
$2,228
$3,600
$5,827.67
$20,558
Ethanol
Production - dry
mill
85% of 170 mills
0
75%
0
0
$0
$0
$0
$0
$0
$0
$0
$0.00
$0
Petroleum
Refineries
150
100%
150
0
$1,085,250
$102,440
$492,000
$594,440
$0
$0
$0
$0.00
$594,440
Total


358









$1,447,417
Cap - Capital costs.
TAC - Total annualized costs (annualized capital costs plus annual costs).
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8. References
ARCADIS. 2004. Memorandum from M. Doom, ARCADIS, to D. Pape, ICF, and E. Scheehle,
EPA. Response to ERG Review and New US M&P Estimates. August 16.
Benyahia, F., M. Abdulkarim, A. Embaby, and M. Rao. 2006. Refinery Wastewater Treatment:
A True Technological Challenge. Presented at the Seventh Annual U. A.E. University Research
Conference, April 2006.
CARB. 2007. Attachments C TO F - Supplemental Materials Document for Staff Report: Initial
Statement of Reasons for Rulemaking, Mandatory Reporting of Greenhouse Gas Emissions
Pursuant to the California Global Warming Solutions Act of 2006 (Assembly Bill 32),
Attachment E: Technical Attachment on Development of Emissions Reporting Requirements for
Oil Refineries and Hydrogen Plants. California Environmental Protection Agency Air Resources
Board. October 19. Available online at: http://www.arb.ca.gov/regact/2007/ghg2007/
suppisor.pdf.
Donovan. 1996. Siting an Ethanol Plant in the Northeast. C.T. Donovan Associates, Inc. Report
presented to Northeast Regional Biomass Program (NRBP). (April). Available online at:
http://www.nrbp.org/pdfs/pub09.pdf. Accessed October 2006.
Energy Information Administration (EIA). 2009. Number and Capacity of Petroleum Refineries.
Available online at: http://www.eia.doe.gov/dnav/pet/pet_pnp_capl_dcu_nus_a.htm
ERG. 2006. Memorandum from D. Bartram and S. Holman ERG, to Melissa Weitz, EPA.
Assessment of Greenhouse Gas Emissions from Wastewater Treatment of U.S. Ethanol
Production Wastewaters. October 10.
ERG, 2008. Memorandum from A. Aguiar and D. Bartram ERG to Melissa Weitz, EPA..
Planned Revisions of the Industrial Wastewater Inventory Emission Estimates for the 1990-2007
Inventory. August 10.
ERG 2010. Memorandum from B. Bicknell, A. Aguiar, and D. Bartram ERG, to Rachel
Schmeltz, EPA. Greenhouse Gas Reporting Rule, Industrial Wastewater Treatments Source
Category, Costs for Final Rule Monitoring Requirements - Revised. March 2010.
Grady, C.P.L., G.T. Daigger, and H.C. Lim. 1999. Biological Wastewater Treatment, Second
Edition. Marcel Dekker, New York.
IPCC. 2006. 2006 IPCC Guidelines for National Greenhouse Gas Inventories: Waste,
Intergovernmental Panel on Climate Change, National Greenhouse Gas Inventories Programme
(Volume 5, Chapter 6).
Merrick. 1998. Wastewater Treatment Options for the Biomass-to-Ethanol Process. Report
presented to National Renewable Energy Laboratory (NREL). Merrick & Company. Subcontract
No. AXE-8-18020-01. October 22.
Metcalf & Eddy, Inc. 1979. Wastewater Engineering: Treatment, Disposal, Reuse, Second
Edition, revised by George Tchobanoglous. McGraw Hill Book Company.
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NAICS. 2007. North American Industrial Classification System. Available online at:
http://www.census.gov/eos/www/naics/.
Nemerow, N.L. and A. Dasgupta. 1991. Industrial and Hazardous Waste Treatment. Van
Nostrand Reinhold. NY. ISBN 0-442-31934-7.
NRBP. 2001. Northeast Regional Biomass Program. An Ethanol Production Guidebook for
Northeast States. Washington, D.C. May 3. Available online at: http://www.nrbp.org/pdfs/
pub26.pdf. Date Accessed: October 2006.
RFA. 2009. Renewable Fuels Association (RFA). Ethanol Industry Overview. Available online
at: http://www.ethanolrfa.org/pages/statistics.
Ruocco. 2006a. Email correspondence from Dr. Joe Ruocco, Phoenix Bio-Systems to Sarah
Holman, ERG. Capacity of Bio-Methanators (Dry Milling). October 6.
Ruocco. 2006b. Email correspondence. Dr. Joe Ruocco, Phoenix Bio-Systems to Sarah Holman,
ERG. "Capacity of Bio-Methanators (Wet Milling)." October 16, 2006.
Timm, C.M. 1985. Water Use, Conservation and Wastewater Treatment Alternatives for Oil
Refineries in New Mexico. NMERDI-2-72-4628.
U.S. Census Bureau. 2002. 2002 Economic Census. Available online at: http://www.census.gov/
econ/census02/.
U.S. EPA. 1993. Development Document for the Proposed Effluent Limitations Guidelines and
Standards for the Pulp, Paper and Paperboard Point Source Category. EPA-821-R-93-019.
Washington, DC. October.
U.S. EPA, 1996. U.S. EPA NPDES Permit Writer's Manual. EPA-833-B-96-003, Washington,
D.C., December, 1996.
U.S. EPA. 1997a. Estimates of Global Greenhouse Gas Emissions from Industrial and Domestic
Wastewater Treatment. United States Environmental Protection Agency, Office of Policy,
Planning, and Evaluation. EPA-600/R-97-091, Washington, DC, September, 1997.
U.S. EPA. 1997b. Supplemental Technical Development Document for Effluent Guidelines and
Standards (Subparts B & E). EPA-821-R-97-011. Washington, DC. October.
U.S. EPA. 2002. Development Document for the Proposed Effluent Limitations Guidelines and
Standards for the Meat and Poultry Products Industry Point Source Category (40 CFR 432).
EPA-821-B-01-007. Washington DC. January 2002.
U.S. EPA. 2004a. Technical Development Document for the Final Effluent Limitations
Guidelines and Standards for the Meat and Poultry Products Point Source Category. EPA-821-R-
04-011. Washington DC.
U.S. EPA, 2004b. NPDES Compliance Inspection Manual. EPA-305x-04-01. Washington, D.C.,
July, 2004.
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U.S. EPA. 2007. Draft Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2005.
February.
U.S. EPA. 2010. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2008. EPA
430-R-10-006. April 15.US Poultry. 2006. Email correspondence from John Starkey,
USPOULTRY, to Deborah Bartram, ERG. August 30.
White and Johnson. 2003. White, P.J. and Johnson, L.A. Editors. Corn: Chemistry and
Technology. 2nd ed. AACC Monograph Series. American Association of Cereal Chemists.
St. Paul, MN.
World Bank. 1999. Pollution Prevention and Abatement Handbook 1998, Toward Cleaner
Production. The International Bank for Reconstruction and Development/The WORLDBANK.
ISBN 0-8213-3638-X Washington, DC.
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