# 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 2010i CONTENTS

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1. I NTRODUCTION AND B ACKGROUND ..................................................................................1-1

2. I NDUSTRY D ESCRIPTION ...................................................................................................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. E MISSION E STIMATES .......................................................................................................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. E STIMATING M ETHANE G ENERATION FROM W ASTEWATER T REATMENT .........................4-1 4.1 Flow Measurement...............................................................................................4-3 4.2 Organic Matter Concentration Measurement and Analysis.................................4-4

5. E STIMATES OF M ETHANE R ECOVERY ...............................................................................5-1 5.1 Biogas Flow Measurement ..................................................................................5-3 5.2 Biogas Composition Monitoring..........................................................................5-3

6. M ETHANE E MISSIONS C ALCULATION ...............................................................................6-1

7. C OSTS FOR GHG R EPORTING ............................................................................................7-1

8. R EFERENCES .....................................................................................................................8-1ii LIST OF TABLES

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3-1 Values Used to Estimate Pulp and Paper CH 4 Emissions................................................ 3-2

3-2 Values Used to Estimate Meat and Poultry Processing CH 4 Emissions.......................... 3-4

3-3 Values Used to Estimate Ethanol Production CH 4 Emissions......................................... 3-5

3-4 Values Used to Estimate Petroleum Refinery CH 4 Emissions ........................................ 3-6

3-5 Estimated Number of Plants Require d 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 Treat ment Monitoring Costs........................................................ 7-2iii LIST OF FIGURES

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2-1 Diagram of Wastewater Treat ment 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 .................... 6-11-1 1. I NTRODUCTION AND B ACKGROUND
This document supports the Mandatory Re porting of Greenhouse Gases Final Rule (Reporting Rule) for the industrial wastewater trea tment source category. The rule is divided into industry-specific categories and other categories that span industries. Categories that span industries include stationary fuel combusti on sources, industrial la ndfills, 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 regulati on. The major changes from the proposed rule include:

 Renaming the source category Indu strial Wastewater Treatment;

 Clarifying the subpart ’s applicability;

 Removing reporting requirements for petrol eum refining oil/water separators and petrochemical facilities; and

 Revising monitoring requirements.

This document provides technical support for the final rule.2-1 2. I NDUSTRY D ESCRIPTION

The industrial wastewater treatment source ca tegory of the Reporting Rule specifically applies to anaerobic processes us ed to treat industrial wastewat er and industrial wastewater treatment sludge at facilities that perform pulp and paper manufacturing, food processing, ethanol production, and petroleu m refining. This section desc ribes industrial wastewater treatment, including the anaerob ic treatment operations covere d under the Reporting Rule, and explains how the Reporting Rule ap plies to this source category.

2.1 Industrial Wastewater Treatment

Wastewater treatment refers to processe s 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 di sinfection) and biological processes. Biological wastewater treatment processes can produce CO 2 and anthropogenic CH 4 and N 2 O emissions.

Industrial wastewater may be tr eated either on site at an industrial facility (industrial wastewater treatment) or in combination with mu nicipal wastewater at a centralized publicly owned treatment plant (POTW) or privately owne d 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, fi nished 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 c ooling water. Municipal wastewater treatment refers to a series of treatment processes us ed to remove contaminants and pollutants from domestic, business, and industria l wastewater collected in city sewers and transported to a centralized wastewater treatment system such as a POTW.

Soluble organic matter is generally removed fr om wastewater using biological processes in which microorganisms consume the organic ma tter for maintenance and growth. The resulting biomass and other suspended solids, together kno wn as sludge, are removed from the treated wastewater before it is discharged to a receiv ing stream. Microorganisms can biodegrade soluble organic material in wastewater under aerobic or anaerobic conditions. Anaerobic wastewater treatment refers to the procedure in which orga nic matter in wastewater or other material is degraded by microorganisms in the absence of oxygen, resulting in the generation of CO 2 and CH 4
. Figure 2-1 shows a simplified diagram outlining the inputs and outputs from wastewater
treatm ent operations. Typically, tr eatment of wastewater begins with primary treatment using processes such as screening or settling. Subsequently, wastewat er may be biologically treated either under aerobic or anaerobic conditions. Most bi ological treatment processes are designed to separate solids from wastewater; often, these solids are treated further in sl udge digesters, which may be either aerobic or anaerobic.Figure 2-1. Diagram of Wastewat er Treatment Inputs and Outputs

As shown in Figure 2-1 , both biological wastewater treatm ent and sludge digestion generate greenhouse gases (GHGs ). Aerobic processes emit CO 2; however, these are not considered anthropogenic emissions a nd 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 CO 2 released from wastewater treatme nt is biogenic in origin (i.e., produced by biological processe s), the Intergovernmental Panel on Climate Change (IPCC) considers these CO 2 emissions to be part of the natural carbon cycle.

Domestic and some industrial wastewaters co ntain nitrogen, usually in the form of urea, ammonia, and proteins. These comp ounds are converted to nitrate (NO 3 ) through the aerobic process of nitrification. Denitr ification occurs under anoxic c onditions (without free oxygen), and involves the biological conversion of nitrate into di-nitrogen gas (N 2 ). N 2 O 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 resu lt, its treatment generates little N 2 O. Emissions of N 2 O from industrial wastewater treatment are not included in either the Inventory or the Reporting Rule. The IPCC has stated that the N 2 O 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 CH 4 . The principal factor in determining the CH 4 generation potential of wastewat er is the amount of degradable organic material in the wastew ater. Common parameters used to measure the organic component of the wastewater are Biochemical Oxygen Demand (BOD 5 ) and Chemical Oxygen Demand (COD). BOD 5 represents the amount of oxygen used by microorganisms to consume the organic matter contained in the wastewater through aerob ic decomposition processes in a 5-day period. COD measures the total material available fo r chemical oxidation (bot h biodegradable and nonbiodegradable).

2-22-3 2.2 Reporting Rule Applicability

The requirements of Subpart II apply to an aerobic processes used to treat industrial wastewater and wastewater trea tment sludges at pulp and paper m ills, food processing facilities, ethanol production facilities, a nd petroleum refineries. These ar e 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 treatm ent processes covered by Subpart II are those processes in which organic matter in wastewater or wastewater tr eatment sludge is degraded by microorganisms in the absence of oxygen, resulting in biogas generation. “Biogas” re fers to the combination of CO 2 , CH 4 , and other gases produced by the biologi cal breakdown of organic matter in the absence of oxygen (Metcalf & Eddy, 1979).

Requirements for this source categor y require facilities to report CH 4 emissions only from anaerobic processes and related biogas de struction devices. Anaerobic processes are biological processes that occur in the absen ce of oxygen (Metcalf & Eddy, 1979). Facilities are required to report CH 4 emissions from anaerobic reactors an d 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 enclos ed vessels used for anaerobic wastewater treatment processe s (Grady, Daigger, and Lim, 1999; Metcalf & Eddy, 1979). The IPCC methodology for estimating CH 4 emissions from industrial wa stewater treatment identifies two types of anaerobic reactors, anaerobi c sludge blanket and fixed film (IPCC, 2006; Table 6-8).

Anaerobic lagoons. Anaerobic lagoons are lined or un lined earthen basins used for wastewater treatment, in which oxygen is absent throughout the de pth of the basin, except for a shallow surface zone (Metcalf & Eddy, 1979). An aerobic lagoons are not equipped with surface aerators. The IPCC methodology for estimating CH 4 emissions from industrial wastewater treatment classifies anaerobic lagoons into two depths: deep (depth more than 2 meters) or shallow (depth less than 2 mete rs) (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 CO 2 and CH 4 (Metcalf & Eddy, 1979). The digested wastewater treatment sludges may have been generated by ae robic treatment processes (e.g., the activated sludge process). If the sludge digester is operate d in the absence of oxygen, it is considered an anaerobic process. Anaerobic sludg e digesters are designed for CH 4 recovery and are not expected to emit methane directly from the digester. The IPCC methodology for estimating CH 42-4 emissions from industrial wastewater treatmen t includes a methodology for estimating emissions from “anaerobic digester for sludge” (IPCC, 2006; Table 6-8).

Biogas destruction devices. Biogas destruction devices incl ude flares, thermal oxidizers, boilers, turbines, internal combustion engines, or any other combustion units used to destroy or oxidize CH 4 contained in biogas.

2.2.2 Industries Included in the Reporting Rule

Subpart II includes industries that both have high levels of BOD 5 or COD in their wastewater and frequently use anaerobic treatment. For these r easons, these industries are also represented in the wastewater tr eatment sector of the U.S. GHG Inventory . These industries (pulp and paper mills, food processing facilities, ethano l production facilities and petroleum refineries) are described in more detail below.

Pulp and Paper Mills. Pulp and paper mills are faciliti es that produce market pulp (i.e., stand-alone pulp facilities), manuf acture pulp and paper (i.e., integrat ed facilities), produce paper products from purchased pulp, produce secondary fibe r from recycled paper, convert paper into paperboard products (e.g., contai ners), or operate coating and laminating processes (40 CFR §98.270).

Wastewater treatment for the pulp and pa per industry typically includes primary treatment (such as screening, sedimentation, a nd flotation/hydrocycloning) to remove solids (World Bank, 1999; Nemerow and Dasgupta, 1991) , followed by secondary biological treatment (such as activated sludge or anaerobic or ae robic lagoons). In the United States, primary treatment is focused on solids removal, equaliz ation, 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 th e wastewater. About 10 percent of pulp and paper mills with treatment systems use settling ponds fo r primary treatment and most of these likely do not perform secondary treatment (EPA, 1993). Neg ligible GHG emissions are assumed to occur during primary treatment.

Approximately 42 percent of the BOD 5 in pulp and paper wastewater passes on to secondary treatment, which consists of activat ed sludge, aerated stab ilization basins, or nonaerated stabilization basins (E PA, 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 system s 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 Re porting Rule, food processing facilities are defined as those that manufacture or process meat, poultry, fru its, and/or vegetables. The North American Industry Classification Syst em (NAICS) is the standard used by federal statistical agencies in cla ssifying business establishments for the purpose of collecting, analyzing, and publishing statistica l data related to the U.S. bus iness economy. It was developed in 1997 to replace the Standard Industrial Classification (S IC) system (NAICS, 2007).2-5 Meat or poultry processing or rendering faci lities are those cove red under NAICS code 3116 (which was SIC code 201, Meat Product Manufacturing). NAICS code 3116 (Animal Slaughtering and Processing) is ma de up of the following subsectors:

 31161 Animal Slaughtering and Processing This industry comprises establishments pr imarily engaged in one or more of the following: (1) slaughtering animals; (2) preparing processed meats and meat byproducts; and (3) rend ering and/or refining animal fat, bones, and meat scraps. This industry includes establishments pr imarily 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 establishm ents primarily engaged in slaughtering animals (except poultry and small game). Establishments that slaughter and prepare meats are includ ed in this industry.

 311612 Meat Processed from Carcasses This U.S. industry comprises establishmen ts primarily engaged in processing or preserving meat and meat by-products (e xcept 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 establishm ents 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 establishmen ts primarily engaged in (1) slaughtering poultry and small game and/or (2) prep aring processed poultry and small game meat and meat by-products.

Fruit or vegetable processing facilities ar e 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 Preservi ng 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 producti on process with inputs of vegetable or animal origin.

NAICS 3114 (Fruit and Vegetable Preservi ng 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 vege tables, and frozen specialty foods (except seafood), such as frozen di nners, entrees, and side dish es; frozen pizza; frozen whipped toppings; and frozen waffles, pancakes, and french toast.2-6  311411 Frozen Fruit, Juice, and Vegetable Manufacturing This U.S. industry comprises establishm ents primarily engaged in manufacturing frozen fruits; frozen vegetables; and fro zen fruit juices, ades, drinks, cocktail mixes and concentrates.

 311412 Frozen Specialty Food Manufacturing This U.S. industry comprises establishm ents primarily engaged in manufacturing frozen specialty foods (except seafood), such as frozen dinners, entrees, and side dishes; frozen pizza; frozen whipped toppi ng; and frozen waffles, pancakes, and french toast.

 31142 Fruit and Vegetable Ca nning, Pickling, and Drying This industry comprises establishments primarily engaged in manufacturing canned, pickled, and dried fruits, vegetabl es, and specialty fo ods. 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; ca nned soups (except seafood); canned dry beans; canned tomato-based sauces, such as catsup, salsa, chili, spaghetti, barbeque, and tomato paste, pickles, relis hes, jams and jellies, dried soup mixes and bullions, and sauerkraut.

 311421 Fruit and Vegetable Canning This U.S. industry comprises establishm ents primarily engaged in manufacturing canned, pickled, and brined fruits and vege tables. Examples of products made inthese establishments are canned juices; canned jams and jellies; canned tomatobased sauces, such as catsup, salsa, chili, spaghetti, barbeque, and tomato paste; pickles, relishes, and sauerkraut.

 311422 Specialty Canning This U.S. industry comprises establishm ents primarily engaged in manufacturing canned specialty foods. Examples of produc ts 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 establishm ents primarily engaged in (1) drying (including freeze-dried) and/or dehydrati ng fruits, vegetables, and soup mixes and bouillon and/or (2) drying and/or dehydr ating ingredients and packaging them with other purchased ingredients, such as rice and dry pasta.

The meat and poultry processing industry ma kes extensive use of anaerobic lagoons in sequence with screening, fat trap s, and dissolved air flotation wh en 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 a nd vegetable processing includes screening, coagulation/settling, and biological treatment (lagooning). The flows are frequently seasonal, and robust treatment systems are preferred for on-site tr eatment. Effluent is suitable for discharge to2-7 the sewer. Like meat and poultry processing, th is industry may also use anaerobic lagoons (Nemerow and Dasgupta, 1991).

The food processing facilities covered by Subpa rt 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 ma nufacture 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 pr oduction facilities as those that produce ethanol from the fermentation of sugar, starch, grai n, or cellulosic biomass feedstocks, or produce ethanol synt hetically from petrochemical f eedstocks, 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 beve rage alcohol. Ethanol can be produced from fermenting sugar-based feedstocks (e.g., molasses and beets), starch- or grainbased feedstocks (e.g., corn, sorghum, and bevera ge waste), and cellulosic biomass feedstocks (e.g., agricultural wastes, wood, and bagasse). Although the Department of Energy predicts cellulosic ethanol production wi ll 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 so le 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 produ ced by the dry milling process. The wastewater generated at ethanol production facilities is handl ed in a variety of ways. Dry milling facilities often combine the resulting evaporator condensat e with other process wa stewaters, such as equipment wash water, scrubber water, and boil er 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 ma y treat the stillage (or processed stillage) from the ethanol fermentation/distillation process se parately or together with steepwater and/or wash water. CH 4 generated in anaerobic digesters is co mmonly 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 fa cilities treat wastewater anaerobically.

Petroleum Refineries. A petroleum refinery is any facili ty engaged in producing gasoline, gasoline blending stocks, naphtha, kerosene, distillate fuel oils, re sidual fuel oils, lubricants, or asphalt (bitumen) through distillation of petrol eum or through redist illation, cracking, or reforming of unfinished petrol eum 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 CO 2 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 GHG2-8 emissions data from downstream sources 1 including industrial wastewat er treatment. Therefore, the rule does not require facilities to report indire ct emissions such as VOC s that can convert to CO 2 once in the atmosphere. EPA expects no direct emissions of CO 2 or other GHGs from these oil/water separators. Following primary treatment, most refineries use biological treatment systems that exhibit anaerobi c conditions, resulting in CH 4 production.

Other Facilities Not Covered by the Reporting Rule. Although other indu strial facilities may use anaerobic wastewater treatm ent processes that generate CH 4 , Subpart II applies only to facilities in the four categories described above. EPA has not char acterized anaerobic wastewater treatment operations or estimated CH 4 emissions in other industri es. 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 em issions; however, downstream sources are not required to report emissions of VOCs or other emissions that convert to CO 2 in the atmosphere.3-1 3. E MISSION E STIMATES
During the development of the Reporting Rule, EPA estimated the number of facilities in each industry that will be requi red 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 an d methodologies developed for the Inventory

. Each industry covered by Subpart II of the Reporting Rule (40 CFR Pa rt 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 tCO 2 e per year in combined emissions from all applicable source categories in the fina l Reporting Rule including pulp and paper manufacturing, and, if present, stationary fuel combusti on sources, industrial solid waste landfills, industrial wa stewater treatment, and any others that may apply.

 Food Processing: Facilities are required to report their GHG emissions only if they exceed 25,000 tCO 2 e per year in combined emissions from all applicable source categories, includi ng, but not limited to sta tionary fuel combustion sources, industrial solid wa ste landfills, and industrial wastewater treatment. Process emissions are not included in dete rmining the threshold, nor are facilities required to report process emissions.

 Ethanol Production: Facilitie s are required to report their GHG emissions only if they exceed 25,000 tCO 2 e per year in combined emissions from all applicable source categories, includi ng, but not limited to sta tionary fuel combustion sources, industrial solid wa ste landfills, and industrial wastewater treatment. Process emissions are not included in dete rmining the threshold, nor are facilities required to report process emissions.

 Petroleum Refining: All petroleum refine ries are required to report their GHG emissions. Refineries must report emissions from their refinery operations and, if present, from stationary fuel combusti on sources, industrial solid waste landfills, industrial wastewater treatment, and a ny other applicable source categories.

The procedures EPA used to estimate the num ber 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 pa per mills in the United States (EPA, 1993). Using assumptions presented in the Inventory , EPA estimated that 25 percent (141) of these mills have anaerobic secondar y treatment and would be required to report their industrial wastewater treatment CH 4 emissions. EPA does not know the production or emissions from these mills, but assumed that all facilities with anaerobic wa stewater treatment would have total facility emissions that exceed th e 25,000 metric tons of CO 2 e per year reporting threshold.

To estimate CH 4 emissions from industrial wastewater treatment at pulp and paper mills, EPA used the methodology presented in the Inventory , which is summarized in Equation 3-1:3-2 CO 2 e = F × P × W × BOD × cf × TA × B 0 × MCF × GWP (3-1)

where: CO 2 e = CO 2 equivalent of methane emissions for facilities required to report (tCO2e). F = Estimated fraction of facilities required to report (decimal). P = Total industry production (thousand metric ton/year). W = Wastewater outflow (m 3 /metric ton). BOD = Organic matter concentration in untreated wastewater, measured as BOD 5 (kg/m 3 ). cf = Factor for conversion of BOD to COD (unitless) TA = Fraction of wastewater BOD treated anaerobically in secondary treatment (decimal). B 0 = Maximum CH 4 -producing capacity (kg CH 4 /kg COD). MCF = Methane conversion fa ctor for anaerobic treatment. GWP = Global warming potential for CH 4
. EPA estimated that pulp and paper industria l wastewater treatment emissions amount to 4,075,044 tCO 2 e, using the values listed in Table 3-1

. Table 3-1. Values Used to Estimate Pulp and Paper CH 4 Emissions

Variable Parameter Value Source
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 (m 3 /ton) 85 World Bank, 1999 Nemerow and Dasgupta, 1991
BOD Organic matter concentration in untreated pulp and paper mill wastewater, as BOD 5 (kg/m 3 ) 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

B 0 Maximum CH 4 -producing capacity (kg CH 4 /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 poul try processing. EPA’s estimates of the number3-3 of facilities in each segment required to repor t and their industrial wastewater treatment CH 4 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 Unite d States. Using assumptions presented in the Inventory , EPA estimated that 5 to 6 pe rcent (100) of thes e facilities have anaerobic secondary treatment resulting in emissions of 123,000 tCO 2 e. Thus, for 100 facilities, the average emissions are 1,230 tCO 2 e per plant per year. Because this estimate is far below the 25,000 tCO 2 e per year threshold for reporting, EPA estimated that no fruits and vegetables processing facility would be required to report its industrial wa stewater treatment GHG emissions.

Meat processing. Meat processing facilities are requi red to report their GHG emissions if they exceed 25,000 tCO 2 e per year in combined emissions from stationary fuel combustion sources, industrial solid waste la ndfills, and industrial wastewater treatment. EPA estimated the number of meat processing facilities that w ould be required to report GHG emissions based on emissions from industrial wastewater treatmen t only. EPA ignored the other sources because it had no information about emissions from stationa ry fuel combustion sources or industrial solid waste landfills at meat processing facilities.

EPA had no data on meat production or GHG emissi ons per plant. As a result, to estimate the number of meat processing faciliti es that would emit more than 25,000 tCO 2 e per year from industrial wastewater treatment processes, EPA back-calculated the prod uction rate that would result in emissions of 25,000 tCO 2 e using Equation 3-2.

P = t/(W × BOD × cf × B 0 × MCF × GWP) × 1,000 kg/ton (3-2)

where: P = Production resulting in GHG emi ssions above the reporting threshold (ton/year). W = Wastewater outflow (m 3 /ton). BOD = Organic matter concentration in the wastewater, measured as BOD, kg/m 3

. cf = Factor for conversion of BOD to COD (unitless) B 0 = Maximum CH 4 -producing capacity (kg CH 4 /kg COD). MCF = Methane conversion factor (decimal). GWP = Global warming potential. t = Reporting threshold (25,000 tCO 2 e/yr).

Using the values listed in Table 3-2 . EPA estimated that 133,000 me tric tons/year of m eat production would result in industr ial wastewater treatment CH 4 emissions that would reach the 25,000 t CO 2 e reporting threshold.

EPA had collected limited production information when it established national effluent limitation guidelines and standa rds for this industry in 2004 (E PA, 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, EP A assumed that 40 facilities processed more than 133,000 tons/year, the tonna ge that reaches the reporting threshold. EPA estimates that 33 percent of meat processing fa cilities have on-site an aerobic treatment. Thus,3-4 EPA estimated that 13 meat processing facilities would be required to re port their industrial wastewater treatment CH 4 emissions and that none of th ese facilities recover biogas.

Table 3-2. Values Used to Estimate Meat and Poultry Processing CH 4 Emissions

Variable Parameter Meat Processing Poultry Processing Source
W Wastewater outflow (m 3 /ton) 5.3 12.5 ARCADIS, 2004 EPA, 2004a
BOD Organic matter concentration in the wastewater, measur ed as BOD (kg/m 3 ) 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

B 0 Maximum CH 4 -producing capacity (kg CH 4 /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 tCO 2 e per year, for a total of 325,000 tCO 2 e.
Poultry processing. Like meat processi ng facilities, poultry processing facilities are required to report if their combin ed emissions from stationary fu el combustion sources, industrial solid waste landfills, and industria l wastewater treatment exceed the threshold. As with meat processing, EPA had no data on pe r plant poultry production or per plant GHG emissions. Again, EPA back-calculated the production rate th at would result in emissions of 25,000 tCO 2 e 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 in dustrial wastewater treatment CH 4 emissions that would reach the 25,000 tCO 2 e reporting threshold.

EPA had limited production inform ation collected when it established national effluent limitation guidelines and standa rds for this industry in 2004 (E PA, 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, EP A assumed that any of these 206 facilities that used anaerobic wastewater tr eatment 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 ha ve 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 proce ssing facilities each emit 25,000 tCO 2 e per year, for a total of 1,250,000 tCO 2 e.3-5 3.3 Ethanol Production Facilities

Ethanol production facilities ar e required to report their GHG emissions if they exceed 25,000 tCO 2 e per year in combined emissions from all applicable source categories, including, but not limited to stationary fuel combusti on sources, industrial soli d waste landfills, and industrial wastewater treatment. EPA estimated th e number of ethanol prod uction 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 Renewa ble Fuels Association (RFA, 2009), EPA estimated that there are 170 etha nol production facilities in the United States. Of these, EPA estimated that 85 percent use dry milling a nd 15 percent use wet milling (EPA, 2007). Using production information provided in the RFA data and parameter values listed in Table 3-3 , EPA estim ated CH 4 emissions from industrial wastewater treatm ent 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 CH 4 Emissions

Variable Parameter Wet Milling Value Dry Milling Value Source
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/m 3 )

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

B 0 Maximum CH 4 -producing capacity (kg CH 4 /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 us e wet milling operations had sufficient production to exceed the 25,000 tCO2e reporting thresh old. However, only one-third of facilities that use wet milling are expected to use an aerobic treatment (ERG , 2008). Therefore, EPA3-6 estimated that four facilities with wet milli ng operations will be required to report GHG emissions (based on emissions from i ndustrial wastewater treatment only).

EPA assumed that all facilities that use dry milling operations had anaerobic treatment in place and none operated a biomethanator 2 . In keeping with the Inventory estimation methodology, EPA assumed that 75 percent of the facilities recovered biogas from their anaerobic treatment processes. EPA estimated th at no ethanol production f acilities that use dry milling operations would meet the reporting th reshold based on emissions from industrial wastewater treatment only.

3.4 Petroleum Refineries

All petroleum refineries ar e required to report their GHG emissions. Refineries must report emissions from their refini ng operations and, if present, fr om stationary fuel combustion sources, industrial solid wa ste landfills, and industrial wastewater treatment.
Based on information from the Energy In formation 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 re quired to report their industrial wastewater treatment CH 4 emissions. Using production in formation from EIA (EIA, 2009) and parameter values listed in Table 3-4 , EPA estimated CH 4 emissions from industrial wastewater treatment for petroleum refi neries using methodology presented in the Inventory , as summarized in Equation 3-1.

Table 3-4. Values Used to Estimate Petroleum Refinery CH 4 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/m 3 ) 0.45 Benyahia et al (2006)

B 0 Maximum CH 4 -producing capacity (kg CH 4 /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 wa stewater BOD treated in secondary treatment 1 EPA, 2010

a – EPA assumes refineries operate trickling filters, rota ting biological contactors, or other systems that exhibit anaerobic conditions. Therefore, EPA selected a CH 4 conversion factor of 0.3 for these treatment systems.

EPA assumed that no petroleum refineries recover biogas and estimated that petroleum refinery industrial wa stewater treatment emissions amount to 616,674 (tCO 2 e) per year (EPA, 2007).

2 A biomethanator is a specific type of anaerobic reactor, treating a higher fraction of indus try wastewater BOD than is typically treated in secondary treatment.3-7 3.5 Summary

Table 3-5 summarizes the number of plants EPA estim ates will be required to report under the Reporting Rule and their estimated emissions. These estimates were used to calculate estimated cost of complian ce, 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 Requi red 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 CH 4 Recovery Estimated Emissions Plants are Required to Report (tCO 2 e) 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 0 616,6744. E STIMATING M ETHANE G ENERATION FROM W ASTEWATER T REATMENT

CH 4 emissions from industrial wastewater treatm ent are a function of the concentration of soluble organic material in an aerobically treated wastewater and an emission factor that characterizes the extent to which waste becomes CH 4 (IPCC, 2006). The emission factor is the product of the maximum CH 4 producing capacity of the wastewater (B 0 ) and the methane conversion factor (MCF) that accounts for the abil ity of the particular system to achieve that maximum CH 4 production. The 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Volume 5, Chapter 6, p.6.2.1, provide values of B 0 for organic material measured as COD and as BOD (see Table 4-1 ).

Most waste water treatment systems will not produce the maximum amount of CH 4 possible because the conditions in the systems are not ideal for CH 4 production. The CH 4 producing potential of a specific system is represented by a parameter known as the CH 4 conversion factor (MCF). This value ranges from 0 to 100 percent and reflect s the capability of a system to produce the maximum achievable CH 4 based on the organic matter present in the wastewater. A higher MCF equates to a higher CH 4 production. MCF values for various types of treatment systems are presen ted 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 em ission factors in Table 4-1 and measured concentrations of organic matter and flow rates, facilities cove red under the Reporting Rule ar e required to estim ate the annual mass of CH 4 they generate from their anaerobic wastewater treatment processes 3 . Facilities must measure both the wastewater flow and the concen tration of organic mate rial entering anaerobic wastewater treatment processes (s pecifically anaerobic reactors and anaerobic lagoons) for this calculation, as shown in Figure 4-1

.

Figure 4-1. Methane Generation

3 Operators of anaerobic sludge digesters are not required to report CH 4 generated. Anaerobic sludge digesters are designed to recover CH 4 and not emit CH 4 directly from the digester apparatus. Operators of anaerobic sludge digesters are required to report the amount of CH 4 recovered and emitted from the recovery system. See Sections 5 and 6 of this document for these requirements.
4-1To reduce the reporting burden, the Reporting Rule allows facilities to use COD in conjunction with Equation 4-1 or 5-day biochemical oxygen demand (BOD 5 ) with Equation 4-2 to calculate CH 4 generation. If facilities measure COD, they should estimate the annual mass of CH 4 generated by each anaerobic wastewater treatmen t process they operate, using Equation 4-1:

(4-1) 

##  

## 

   52

1w ow w 4 0.001 MCF BCOD Flow GCH 

## 

where: CH 4 G = Annual mass CH 4 generated from the anaerob ic wastewater treatment process (metric tons). Flow n = Volume of wastewater sent to an anaerobic wast ewater treatment process in week n (m 3 /week). COD n = Average weekly concentration of COD of wastewater entering an anaerobic wastewater treatment process (for month n)(kg/m 3 ). B 0 = Maximum CH 4 producing potential of wastewater (kg CH 4 /kg COD), use the value 0.25. MCF = CH 4 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 BOD 5 , they should estimate the annual mass of CH 4 generated by each anaerobic wastewater treatment pro cess they operate, using Equation 4-2:

(4-2) 

#   

   52

1w ow5, w 4 0.001 MCF B BOD Flow GCH

where: CH 4 G = Annual mass of CH 4 generated from the anaerobic wastewater treatment process (metric tons). Flow n = Volume of wastewater sent to an anaerobic wast ewater treatment process in week n (m 3 /week). BOD 5,n = Average weekly concentration of 5-day BOD of wastewater entering an anaerobic wastewater treatment process for month n (kg/m 3 ). B 0 = Maximum CH 4 producing potential of wastewater (kg CH 4 /kg BOD 5 ), use the value 0.6. MCF = CH 4 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.

4-24-3 Table 4-1. Emission Factors

Factors Default Value Units
B 0 – for facilities monitoring COD 0.25 kg CH 4 /kg COD

B 0 – for facilities monitoring BOD 5 0.60 kg CH 4 /kg BOD 5 MCF – anaerobic reactor (e.g., upflow anaerobic slu dge 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 CH 4 generation using Equations 4-1 or 4-2, facilities are required to measure both flow and either the COD or BOD 5 concentration of wast ewater 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 anaer obic wastewater treatment proce ss, following all preliminary and primary treatment steps, as shown in Figure 4-1

.
4.1 Flow Measurement

Flow can be measured with hydraulic struct ures such as flumes and weirs that are inserted in open channel flow (flow in conduits th at are not full). Flow can also be measured with meters (e.g., electromagnetic, Venturi, ultrasonic) that are appropriate fo r closed channel flow (flow in a liquid-full conduit). Fa cilities must measure the flow rate for the 24-hour period for which they collect samples analyzed for COD or BOD 5 concentration. Also, the flow measurement location must correspond to the loca tion used to collect samples analyzed for the COD or BOD 5 concentration.

Facilities may measure flow rate usi ng one of the methods specified below:

 ASME MFC–3M–2004 Measurement of Flui d Flow in Pipes Using Orifice, Nozzle, and Venturi;

 ASME MFC–5M–1985 (Reaffirmed 1994) Me asurement 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 inst ructions for the wastewater flow measurement device.

Any chosen flow measurement system must me asure the entire discharge flow; it must be accurate and in working order, calibrated, and main tained. Facilities are re quired to calibrate all wastewater flow measurement devices prior to th e first year of reporting and recalibrate them either biennially (every 2 year s) or at the minimum frequency specified by the manufacturer. Wastewater flow measurement devices must be calibrated using the procedures specified by the4-4 device manufacturer. For more inform ation 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 CH 4 generation, in addition to wastewater flow, facilities are also required to measure organic matter concentratio n in the form of either BOD 5 or COD. Facilities must collect samples representative of the wast ewater entering their anaerobic treatment systems. Wastewater typically flows through a pipe or a conduit and both the flow ra te 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 samp led stream does not vary in concentration over time.

 Time-weighted composite sample: equa l 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. Timeweighted composites are repres entative 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 individu al aliquot proportional to the flow, while maintaining a constant time interval between the aliquots.

Flow proportional samples can be collected w ith an automatic sampler and a compatible flow measuring device, with a fl ow chart and an automatic sample r 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 BOD 5 concentration of the waste stream does not vary in a 24-hour period. EPA also considered allowi ng facilities to collect timeweighted 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 stre am meets the conditions necessary for these types of sampling would require the facility to collect additional sample s. For this reason, the final Reporting Rule requires facilities to co llect a flow-proportional composite sample. The Reporting Rule requires either a constant time in terval between samples, keeping sample volume proportional to stream flow, or a constant sample volume with the time interval between samples4-5 proportional to stream flow. The sample must represent the average COD or BOD 5 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 co llect a m inimum of four sa mples 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 in fluent to the anaerobi c wastewater treatment process, without imposing an unnecessary burden on reporters. For more information on sampling, see the NPDES Permit Writer’s Manual (U.S. EPA, 1996) and the NPDES Compliance Inspection Manual (U.S. EPA, 2004b).

Facilities must determine the organic ma tter concentration in wastewater treated anaerobically using analytic al methods for COD or BOD 5 specified in 40 CFR part 136.3 Table 1B. When determining concentrations of wa stewater influent to th e anaerobic wastewater treatment process to calculate CH 4 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 th e concentration of the undilute d sample. The undiluted sample concentration is used to calculate CH 4 generation.5. E STIMATES OF M ETHANE R ECOVERY
“Biogas” refers to the combination of CO 2 , CH 4 , and other gases produced by the biological breakdown of organic ma tter in the absence of oxygen. So me facilities recover some or all of the biogas generated by anaerobic wast ewater treatment and anaerobic sludge digestion and route the recovered biogas to a destruction device. These de vices include flares, thermal oxidizers, boilers, turbines, internal combustion e ngines, or any other co mbustion units used to destroy or oxidize CH 4 contained in the biogas. Figure 5-1 depicts biogas recovery from anaerob ic wastewater treatment.

Figure 5-1. Diagram of Biogas Recovery from Anaerobic Wastewater Treatment

Facilities that use aerobic processes to trea t 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.

5-1Figure 5-2. Diagram of Biogas Recovery from Anaerobic Sludge Digestion

Subpart II of the Reporting Rule requires fac ilities to calculate and report the amount of CH 4 they recover. They must calculate CH 4 recovery using Equation 5-1.

(5-1) 

##  

## 

  M

1m mCH4 m CF )(C (V) R 

## 

where: R = Annual quantity of CH 4 recovered from anaerobic reactor, digester, or lagoon (metric tons CH 4 /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. V m = Cumulative volumetric flow for the measurement period in actual cubic feet (acf). If no biogas was reco vered 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 determ ine the volume of gas recovered during a monitoring period and the CH 4 concentration of the gas. These measured values may be multiplied by a number of correction factors:

 Volumetric moisture correction term fo r 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.

5-25-3 If a facility continuously monitors the CH 4 concentration and these correction factors using a meter specifically for CH 4 gas, they must use this system to calculate CH 4 recovery. A fully integrated system that directly reports CH 4 content only requires the facility to sum the results of all monitoring pe riods for a given year.

5.1 Biogas Flow Measurement

To estimate the annual mass of CH 4 recovered, facilities ar e required to continuously monitor the recovered biogas flow rate. Every fa cility 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 fl ow rate using one of the methods specified below:

 ASME MFC-3M-2004, Measurement of Fl uid Flow in Pipes Using Orifice, Nozzle, and Venturi;

 ASME MFC-4M-1986 (Reaffirmed 1997), Me asurement of Gas Flow by Turbine Meters;

 ASME MFC-6M-1998, Measurement of Fl uid Flow in Pipes Using Vortex Flowmeters;

 ASME MFC-7M-1987 (Reaffirmed 1992), Me asurement of Gas Flow by Means of Critical Flow Venturi Nozzles;

 ASME MFC-11M-2006 Measurement of Fl uid Flow by Means of Coriolis Mass Flowmeters;

 ASME MFC-14M-2003 Measurement of Fl uid Flow Using Small Bore Precision Orifice Meters; or

 ASME MFC-18M-2001 Measurement of Flui d Flow using Variable Area Meters;

or

 Method 2A or 2D at 40 CFR part 60, appendix A-1.

A facility may measure biogas flow using a method other than those listed above; however, they must follow the manufacturer’s inst ructions for the gas flow measurement device. Each gas flow meter must be calibrated every tw o years or at the minimum frequency specified by the manufacturer.

A facility is required to determine temperatur e 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 CH 4 concentration is determined on a dry basis and bioga s flow is determined on a wet basis, or viceversa, and the flow meter does not automatically correct for moistu re 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 indu stry 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 CH 4 concentration. If a facility has equipm ent that continuously monitors the CH 4 concentration, the facility must use it. If a facility is not currently monitoring the biogas CH 4 concentration, they5-4 must use either installed or portable equipment to monitor it weekly. Weekly monitoring provides an adequate number of samples to eval uate the variability and uncertainly associated with CH 4 generation.

Facilities with biogas recove ry from anaerobic processes must measure gas composition with a monitor capable of measuring the concentration of CH 4 in the recovered biogas using either one of the methods specified below or as specified by the device ma nufacturer 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 mini mum 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), Sta ndard Practice for Analysis of Reformed Gas by Gas Chromatography;

 GPA Standard 2261-00, Analysis for Natura l 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 CH 4 concentration.6. M ETHANE E MISSIONS C ALCULATION
In addition to reporting CH 4 generation, facilities must report the amount of CH 4 emitted to the atmosphere. For facilities that do not recover biogas, total emissions equal the CH 4 generation of each anaerobic reactor or lagoon and can be estimated using Equation 6-1.

CH 4 E = CH 4 G (6-1)

where: CH 4 E = Annual mass of CH 4 emissions from the wastewater treatment process (metric tons). CH 4 G = Annual mass of CH 4 generated from the wastewat er treatment process, as calculated in Equations 3- 1 or 3-2 (metric tons).

Leakage. Facilities that recover biogas fr om either anaerobic wastewater treatment operations or sludge digesters must take into account the inefficien cy of the recovery process as depicted in Figure 6-1 . Leakage refers to the annual mass of CH 4 that is generated but not recovered.

Figure 6-1. Diagram of Leak age From Anaerobic Sludge Digestion Biogas Recovery

For anaerobic processes with biogas recover y, facilities must calculate leakage using Equation 6-2 by multiplying recovery (calculated us ing Equation 5-1) by a collection efficiency factor in Table 6-1 . This allows facilities to quantify the am ount of CH 4 that is not captured by their destruction device.

     

 1 CE

1 RLCH 4 (6-2)

6-16-2 where: CH 4 L = Leakage at the anaerob ic process (metric tons CH 4 ). R = Annual quantity of CH 4 recovered from anaerobic reactor, anaerobic lagoon, or anaerobic digester, as calculated in Equation 5-1 (metric tons CH 4 ). CE = CH 4 collection efficiency of anaerob ic process, as specified in Table 6-1 (decim al).

Table 6-1. Collection Efficienci es of Anaerobic Processes

Anaerobic Process Type Cover Type Methane Collection Efficiency Bank to bank, impermeable 0.975 Covered anaerobic lagoon (biogas capture) 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 unit s destroy or oxidize CH 4 contained in the biogas, producing CO 2 and water. However, biogas destruction devices operate with less than 100 percent efficiency. This means the device exhaust gases will contain some CH 4 . At facilities with biogas r ecovery, reported total emissions must take into account the destruction of CH 4 by these recovery devices. These facilities’ total annual mass of CH 4 emissions are equal to their leakage rate plus their total recovery multiplied by the recovery device CH 4 destruction efficiency (DE). Total emissions equal the quantity that leaks from the anaerobic process plus the quant ity not destroyed in the destruction device, as shown in Equation 6-3.

CH 4 E = CH 4 L + R (1 – DE) (6-3)

where: CH 4 E = Annual quantity of CH 4 emitted (metric tons/yr). CH 4 L = Leakage at the anaerobic process, as calculated in E quation 6-2 (metric tons CH 4 ). R = Annual quantity of CH 4 recovered from the anaerobic reactor digester, or lagoon, as calculated in E quation 5-1 (metric tons CH 4 ). DE = Destruction efficien cy (i.e., the fraction of CH 4 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 ma y operate a primary destruction device and a backup). Total emissions for facilities with bioga s destruction devices must be estimated using Equation 6-4.

CH 4 E = CH 4 L + R (1 – (DE 1 ×f Dest_1 )) + R (1 – (DE 2 × F Dest_2 )) ( 6

- 4 )

where: CH 4 E = Annual quantity of CH 4 emitted (metric tons/yr). CH 4 L = Leakage at the anaerobic process, as calculated in E quation 6-2 (metric tons CH 4 ).6-3 R = Annual quantity of CH 4 recovered from the anaerobi c reactor, digester, or lagoon, as calculated in E quation 5-1 (metric tons CH 4 ). DE 1 = Primary destruction device CH 4 destruction efficiency (lesser of manufacturer’s specified destruction efficiency and 0.99). If the gas is transported off-site for destruction, use DE=1. f Dest_1 = Fraction of hours the primary destru ction device was operating (device operating hours/8760 hours per year). If the gas is transported off-site for destruction, use f Dest =1. DE 2 = Back-up destruction device CH 4 destruction efficiency (lesser of manufacturer’s specified dest ruction efficiency and 0.99). f Dest_2 = Fraction of hours the back-up destru ction device was operating (device operating hours/8760 hours per year).7-1 7. C OSTS FOR GHG R EPORTING
The Reporting Rule requires operators to monitor their CH 4 -generating processes by measuring the amount of wastewater entering the anaerobic treatment pro cess, the concentration of organic material in the wastew ater prior to treatment, the volum e of biogas recovered, and the concentration of CH 4 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 th at a typical facility w ould incur to meet the requirement.

The estimates include one-time capital costs to purchase and install monitoring devices and recurring annual costs for analyt ical services, supplies, and labor. Table 7-1 summarizes the total costs EPA estim ates will be incurred by f acilities in each industry covered by Subpart II. EPA estimated that these monitoring requireme nts would cost, on aver age, $4,083 per year per facility (total annualized costs) or $1.4 m illion 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, Industria l Wastewater Treatments Source Category, Costs for Final Rule Monitoring Requirements – Revised (ERG, 2010).7-2Table 7-1. Industrial WastewaterTreatment Monitoring CostsNational (Scaled-Up) Estimated CostsNational (Scaled-Up) Estimated CostsNational (ScaledUp) EstimatedCostsCategoryNo. ofPlantsRequiredto Report%PlantswithAnaerobicTreatmentNo. ofPlantswithAnaerobicTreatmentNo. ofPlantswith CH4RecoveryWWMonitoringCosts -CapWWMonitoringCosts -AnnualizedCapWWMonitoringCosts -AnnualWWMonitoringCosts -TACCH4RecoveryMonitoringCosts -CapCH4RecoveryMonitoringCosts -AnnualizedCapCH4RecoveryMonitoringCosts -AnnualCH4RecoveryMonitoringCosts -TACTotal(WW +CH4recovery)Monitoring TACPulp and Paper56525%1410$1,428,843$134,873$463,300$598,1730$0$0$0.00$598,173Food Processing63100%630$455,805$43,025$206,640$249,665$0$0$0$0.00$249,665EthanolProduction - wetmill15% of 170 mills4100%44$17,064$1,611$13,120$14,731$23,600$2,228$3,600$5,827.67$20,558EthanolProduction - drymill85% of 170 mills075%00$0$0$0$0$0$0$0$0.00$0PetroleumRefineries150100%1500$1,085,250$102,440$492,000$594,440$0$0$0$0.00$594,440Total358$1,447,417Cap – Capital costs.TAC – Total annualized costs (annualized capital costs plus annual costs).8-1 8. R EFERENCES

ARCADIS. 2004. Memorandum from M. Doorn, ARCADIS, to D. Pape, ICF, and E. Scheehle, EPA. Response to ERG Review and New US M&P Estimates. August 16.

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