Subpart II—Industrial Wastewater Treatment

§98.350 Definition of source category.

(a) This source category consists of anaerobic processes used to treat industrial wastewater 

and industrial wastewater treatment sludge at facilities that perform the operations listed in this 

paragraph.

(1) Pulp and paper manufacturing.

(2) Food processing.

(3) Ethanol production.

(4) Petroleum refining.

(b) An anaerobic process is a procedure in which organic matter in wastewater, wastewater 

treatment sludge, or other material is degraded by micro-organisms in the absence of oxygen, 

resulting in the generation of CO2 and CH4. This source category consists of the following: 

anaerobic reactors, anaerobic lagoons, anaerobic sludge digesters, and biogas destruction devices 

(for example, burners, boilers, turbines, flares, or other devices).

(1) An anaerobic reactor is an enclosed vessel used for anaerobic wastewater treatment 

(e.g., upflow anaerobic sludge blanket, fixed film).

(2) Ananaerobic sludge digester is an enclosed vessel in which wastewater treatment sludge 

is degraded anaerobically.

(3) Ananaerobic lagoon is a lined or unlined earthen basin used for wastewater treatment, 

in which oxygen is absent throughout the depth of the basin, except for a shallow surface zone. 

Anaerobic lagoons are not equipped with surface aerators. Anaerobic lagoons are classified as 

deep (depth more than 2 meters) or shallow (depth less than 2 meters).
(c) This source category does not include municipal wastewater treatment plants or separate 

treatment of sanitary wastewater at industrial sites.

§98.351 Reporting threshold.

You must report GHG emissions under this subpart if your facility meets all of the 

conditions under paragraphs (a) or (b) of this section:

(a) Petroleum refineries and pulp and paper manufacturing.

(1) The facility is subject to reporting under subpart Y of this part (Petroleum Refineries) or 

subpart AA of this part (Pulp and Paper Manufacturing).

(2) The facility meets the requirements of either §98.2(a)(1) or (2).

(3) The facility operates an anaerobic process to treat industrial wastewater and/or industrial 

wastewater treatment sludge.

(b) Ethanol production and food processing facilities.

(1) The facility performs an ethanol production or food processing operation, as defined in 

§98.358 of this subpart.

(2) The facility meets the requirements of §98.2(a)(2).

(3) The facility operates an anaerobic process to treat industrial wastewater and/or industrial 

wastewater treatment sludge.

§98.352 GHGs to report.

(a) You must report CH4 generation, CH4 emissions, and CH4 recovered from treatment of 

industrial wastewater at each anaerobic lagoon and anaerobic reactor.

(b) You must report CH4 emissions and CH4 recovered from each anaerobic sludge digester.

(c) You must report CH4 emissions and CH4 destruction resulting from each biogas 

collection and biogas destruction device.
(d) You must report under subpart C of this part (General Stationary Fuel Combustion 

Sources) the emissions of CO2, CH4, and N2O from each stationary combustion unit associated 

with the biogas destruction device, if present, by following the requirements of subpart C of this 

part.

§98.353 Calculating GHG emissions.

(a) For each anaerobic reactor and anaerobic lagoon, estimate the annual mass of CH4

generated according to the applicable requirements in paragraphs (a)(1) through (a)(2) of this 

section.

(1) If you measure the concentration of organic material entering the anaerobic reactors or 

anaerobic lagoon using methods for the determination of chemical oxygen demand (COD), then 

estimate annual mass of CH4 generated using Equation II-1 of this section.

Where:

CH4Gn = Annual mass CH4 generated from the nth anaerobic wastewater treatment process 

(metric tons).

n = Index for processes at the facility, used in Equation II-7.

w = Index for weekly measurement period.

Floww = Volume of wastewater sent to an anaerobic wastewater treatment process in week w 

(m3/week), measured as specified in §98.354(d).

CODw = Average weekly concentration of chemical oxygen demand of wastewater entering an 

anaerobic wastewater treatment process (for week w)(kg/m3), measured as specified in 

§98.354(b) and (c).

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 II-1 of this subpart.

0.001 = Conversion factor from kg to metric tons.

(2) If you measure the concentration of organic material entering an anaerobic reactor or 

anaerobic lagoon using methods for the determination of 5-day biochemical oxygen demand 

(BOD5), then estimate annual mass of CH4 generated using Equation II-2 of this section.

Where:

CH4Gn = Annual mass of CH4 generated from the anaerobic wastewater treatment process 

(metric tons).

n = Index for processes at the facility, used in Equation II-7.

w = Index for weekly measurement period.

Floww = Volume of wastewater sent to an anaerobic wastewater treatment process in week 

w(m3/week), measured as specified in §98.354(d).

BOD5,w = Average weekly concentration of 5-day biochemical oxygen demand of wastewater 

entering an anaerobic wastewater treatment process for week w(kg/m3), measured as 

specified in §98.354(b) and (c).

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 II-1 to this subpart.

0.001 = Conversion factor from kg to metric tons.

(b) For each anaerobic reactor and anaerobic lagoon from which biogas is not recovered, 

estimate annual CH4 emissions using Equation II-3 of this section.

Where:
CH4En = Annual mass of CH4 emissions from the wastewater treatment process n from which 

biogas is not recovered (metric tons).

CH4Gn = Annual mass of CH4 generated from the wastewater treatment process n, as calculated 

in Equation II-1 or II-2 of this section (metric tons).

(c) For each anaerobic sludge digester, anaerobic reactor, or anaerobic lagoon from which 

some biogas is recovered, estimate the annual mass of CH4 recovered according to the 

requirements in paragraphs (c)(1) and (c)(2) of this section. To estimate the annual mass of CH4

recovered, you must continuously monitor biogas flow rate and determine the volume of biogas 

each week and the cumulative volume of biogas each year that is collected and routed to a 

destruction device as specified in §98.354(h). If the gas flow meter is not equipped with 

automatic correction for temperature, pressure, or, if necessary, moisture content, you must 

determine these parameters as specified in paragraph (c)(2)(ii) of this section.

(1) If you continuously monitor CH4 concentration (and if necessary, temperature, pressure, 

and moisture content required as specified in §98.354(f)) of the biogas that is collected and 

routed to a destruction device using a monitoring meter specifically for CH4 gas, as specified in 

§98.354(g), you must use this monitoring system and calculate the quantity of CH4 recovered for 

destruction using Equation II-4 of this section. A fully integrated system that directly reports 

CH4 quantity requires only the summing of results of all monitoring periods for a given year.

Where:

Rn = Annual quantity of CH4 recovered from the nth anaerobic reactor, sludge digester, or lagoon 

(metric tons CH4/yr)

n = Index for processes at the facility, used in Equation II-7.
M = Total number of measurement periods in a year. Use M = 365 (M = 366 for leap years) for 

daily averaging of continuous monitoring, as provided in paragraph (c)(1)of this 

section. Use M = 52 for weekly sampling, as provided in paragraph (c)(2)of this 

section.

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.

(KMC)m = Moisture correction term for the measurement period, volumetric basis.

= 1 when (V)m and (CCH4)m are measured on a dry basis or if both are measured on a 

wet basis.

= 1−(fH2O)m when (V)m is measured on a wet basis and (CCH4)m is measured on a dry

basis.

= 1/[1−(fH2O)m] when (V)m is measured on a dry basis and (CCH4)m is measured on a 

wet basis.

(fH2O)m = Average moisture content of biogas during the measurment period, volumetric basis, 

(cubic feet water per cubic feet biogas).

(CCH4)m = Average CH4 concentration of biogas during the measurement period, (volume %).

0.0423 = Density of CH4 lb/cf at 520 °R or 60 °F and 1 atm.

520 °R = 520 degrees Rankine.

Tm = Average temperature at which flow is measured for the measurement period (°R). If the 

flow rate meter automatically corrects for temperature to 520° R, replace “520° R/Tm” 

with “1”.
Pm = Average pressure at which flow is measured for the measurement period (atm). If the flow 

rate meter automatically corrects for pressure to 1 atm, replace “Pm/1” with “1”.

0.454/1,000 = Conversion factor (metric ton/lb).

(2) If you do not continuously monitor CH4 concentration according to paragraph (c)(1) of 

this section, you must determine the CH4 concentration, temperature, pressure, and, if necessary, 

moisture content of the biogas that is collected and routed to a destruction device according to 

the requirements in paragraphs (c)(2)(i) through (c)(2)(ii) of this section and calculate the 

quantity of CH4 recovered for destruction using Equation II-4 of this section.

(i) Determine the CH4 concentration in the biogas that is collected and routed to a 

destruction device in a location near or representative of the location of the gas flow meter at 

least once each calendar week; if only one measurement is made each calendar week, there must 

be least three days between measurements. For a given calendar week, you are not required to 

determine CH4 concentration if the cumulative volume of biogas for that calendar week, 

determined as specified in paragraph (c) of this section, is zero.

(ii) If the gas flow meter is not equipped with automatic correction for temperature, 

pressure, or, if necessary, moisture content:

(A) Determine the temperature and pressure in the biogas that is collected and routed to a 

destruction device in a location near or representative of the location of the gas flow meter at 

least once each calendar week; if only one measurement is made each calendar week, there must 

be at least three days between measurements.

(B) If the CH4 concentration is determined on a dry basis and biogas flow is determined on 

a wet basis, or CH4 concentration is determined on a wet basis and biogas flow is determined on 

a dry basis, and the flow meter does not automatically correct for moisture content, determine the 
moisture content in the biogas that is collected and routed to a destruction device in a location 

near or representative of the location of the gas flow meter at least once each calendar week that 

the cumulative biogas flow measured as specified in §98.354(h) is greater than zero; if only one 

measurement is made each calendar week, there must be at least three days between 

measurements.

(d) For each anaerobic sludge digester, anaerobic reactor, or anaerobic lagoon from which 

some quantity of biogas is recovered, you must estimate both the annual mass of CH4 that is 

generated, but not recovered, according to paragraph (d)(1) of this section and the annual mass of 

CH4 emitted according to paragraph (d)(2) of this section.

(1) Estimate the annual mass of CH4 that is generated, but not recovered, using Equation II5 of this section.

Where:

CH4Ln = Leakage at the anaerobic process n (metric tons CH4).

n = Index for processes at the facility, used in Equation II-7.

Rn = Annual quantity of CH4 recovered from the nth anaerobic reactor, anaerobic lagoon, or 

anaerobic sludge digester, as calculated in Equation II-4 of this section (metric tons 

CH4).

CE = CH4 collection efficiency of anaerobic process n, as specified in Table II-2 of this subpart 

(decimal).

(2) For each anaerobic sludge digester, anaerobic reactor, or anaerobic lagoon from which 

some quantity of biogas is recovered, estimate the annual mass of CH4 emitted using Equation II6 of this section.
Where:

CH4En = Annual quantity of CH4 emitted from the process n from which biogas is recovered 

(metric tons).

n = Index for processes at the facility, used in Equation II-7.

CH4Ln = Leakage at the anaerobic process n, as calculated in Equation II-5 of this section (metric 

tons CH4).

Rn = Annual quantity of CH4 recovered from the nth anaerobic reactor or anaerobic sludge 

digester, as calculated in Equation II-4 of this section (metric tons CH4).

DE1 = Primary destruction device CH4 destruction efficiency (lesser of manufacturer's specified 

destruction efficiency and 0.99). If the biogas is transported off-site for destruction, use 

DE = 1.

fDest_1 = Fraction of hours the primary destruction device was operating calculated as the annual 

hours when the destruction device was operating divided by the annual operating hours 

of the biogas recovery system. If the biogas is transported off-site for destruction, use 

fDest = 1.

DE2 = Back-up destruction device CH4 destruction efficiency (lesser of manufacturer's specified 

destruction efficiency and 0.99).

fDest_2 = Fraction of hours the back-up destruction device was operating calculated as the annual 

hours when the destruction device was operating divided by the annual operating hours 

of the biogas recovery system.
(e) Estimate the total mass of CH4 emitted from all anaerobic processes from which biogas 

is not recovered (calculated in Eq. II-3) and all anaerobic processes from which some biogas is 

recovered (calculated in Equation II-6) using Equation II-7 of this section.

Where:

CH4ET = Annual mass CH4 emitted from all anaerobic processes at the facility (metric tons).

n = Index for processes at the facility.

CH4En = Annual mass of CH4 emissions from process n (metric tons).

j = Total number of processes from which methane is emitted.

§98.354 Monitoring and QA/QC requirements.

(a) For calendar year 2011 monitoring, the facility may submit a request to the 

Administrator to use one or more best available monitoring methods as listed in §98.3(d)(1)(i) 

through (iv). The request must be submitted no later than October 12, 2010 and must contain the 

information in §98.3(d)(2)(ii). To obtain approval, the request must demonstrate to the 

Administrator's satisfaction that it is not reasonably feasible to acquire, install, and operate a 

required piece of monitoring equipment by January 1, 2011. The use of best available monitoring 

methods will not be approved beyond December 31, 2011.

(b) You must determine the concentration of organic material in wastewater treated 

anaerobically using analytical methods for COD or BOD5 specified in 40 CFR 136.3 Table 1B. 

For the purpose of determining concentrations of wastewater influent to the anaerobic 

wastewater treatment process, samples may be diluted to the concentration range of the approved 

method, but the calculated concentration of the undiluted wastewater must be used for 

calculations and reporting required by this subpart.
(c) You must collect samples representing wastewater influent to the anaerobic wastewater 

treatment process, following all preliminary and primary treatment steps (e.g., after grit removal, 

primary clarification, oil-water separation, dissolved air flotation, or similar solids and oil 

separation processes). You must collect and analyze samples for COD or BOD5 concentration at 

least once each calendar week that the anaerobic wastewater treatment process is operating; if 

only one measurement is made each calendar week, there must be at least three days between 

measurements. You must collect a sample that represents the average COD or BOD5

concentration of the waste stream over a 24-hour sampling period. You must collect a minimum 

of four sample aliquots per 24-hour period and composite the aliquots for analysis. Collect a 

flow-proportional composite sample (either constant time interval between samples with sample 

volume proportional to stream flow, or constant sample volume with time interval between 

samples proportional to stream flow). Follow sampling procedures and techniques presented in 

Chapter 5, Sampling, of the “NPDES Compliance Inspection Manual,” (incorporated by

reference, see §98.7) or Section 7.1.3, Sample Collection Methods, of the “U.S. EPA NPDES 

Permit Writers' Manual,” (incorporated by reference, see §98.7).

(d) You must measure the flowrate of wastewater entering anaerobic wastewater treatment 

process at least once each calendar week that the process is operating; if only one measurement 

is made each calendar week, there must be at least three days between measurements. You must 

measure the flowrate for the 24-hour period for which you collect samples analyzed for COD or 

BOD5 concentration. The flow measurement location must correspond to the location used to 

collect samples analyzed for COD or BOD5 concentration. You must measure the flowrate using 

one of the methods specified in paragraphs (d)(1) through (d)(5) of this section or as specified by 

the manufacturer.
(1) ASME MFC-3M-2004 Measurement of Fluid Flow in Pipes Using Orifice, Nozzle, and 

Venturi (incorporated by reference, see §98.7).

(2) ASME MFC-5M-1985 (Reaffirmed 1994) Measurement of Liquid Flow in Closed 

Conduits Using Transit-Time Ultrasonic Flowmeters (incorporated by reference, see §98.7).

(3) ASME MFC-16-2007 Measurement of Liquid Flow in Closed Conduits with 

Electromagnetic Flowmeters (incorporated by reference, see §98.7).

(4) ASTM D1941-91 (Reapproved 2007) Standard Test Method for Open Channel Flow 

Measurement of Water with the Parshall Flume, approved June 15, 2007, (incorporated by 

reference, see §98.7).

(5) ASTM D5614-94 (Reapproved 2008) Standard Test Method for Open Channel Flow 

Measurement of Water with Broad-Crested Weirs, approved October 1, 2008, (incorporated by

reference, see §98.7).

(e) All wastewater flow measurement devices must be calibrated prior to the first year of 

reporting and recalibrated 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 device manufacturer.

(f) For each anaerobic process (such as anaerobic reactor, sludge digester, or lagoon) from 

which biogas is recovered, you must make the measurements or determinations specified in 

paragraphs (f)(1) through (f)(3) of this section.

(1) You must continuously measure the biogas flow rate as specified in paragraph (h) of this 

section and determine the cumulative volume of biogas recovered.

(2) You must determine the CH4 concentration of the recovered biogas as specified in 

paragraph (g) of this section at a location near or representative of the location of the gas flow 
meter. You must determine CH4 concentration either continuously or intermittently. If you 

determine the concentration intermittently, you must determine the concentration at least once 

each calendar week that the cumulative biogas flow measured as specified in paragraph (h) of 

this section is greater than zero, with at least three days between measurements.

(3) As specified in §98.353(c) and paragraph (h) of this section, you must determine 

temperature, pressure, and moisture content as necessary to accurately determine the biogas flow 

rate and CH4 concentration. You must determine temperature and pressure if the gas flow meter 

or gas composition monitor do not automatically correct for temperature or pressure. You must 

measure moisture content of the recovered biogas if the biogas flow rate is measured on a wet 

basis and the CH4 concentration is measured on a dry basis. You must also measure the moisture 

content of the recovered biogas if the biogas flow rate is measured on a dry basis and the CH4

concentration is measured on a wet basis.

(g) For each anaerobic process (such as an anaerobic reactor, sludge digester, or lagoon) 

from which biogas is recovered, operate, maintain, and calibrate a gas composition monitor 

capable of measuring the concentration of CH4 in the recovered biogas using one of the methods 

specified in paragraphs (g)(1) through (g)(6) of this section or as specified by the manufacturer.

(1) Method 18 at 40 CFR part 60, appendix A-6.

(2) ASTM D1945-03, Standard Test Method for Analysis of Natural Gas by Gas 

Chromatography (incorporated by reference, see §98.7).

(3) ASTM D1946-90 (Reapproved 2006), Standard Practice for Analysis of Reformed Gas 

by Gas Chromatography (incorporated by reference, see §98.7).

(4) GPA Standard 2261-00, Analysis for Natural Gas and Similar Gaseous Mixtures by Gas 

Chromatography (incorporated by reference, see §98.7).
(5) ASTM UOP539-97 Refinery Gas Analysis by Gas Chromatography (incorporated by 

reference, see §98.7).

(6) As an alternative to the gas chromatography methods provided in paragraphs (g)(1) 

through (g)(5) of this section, you may use total gaseous organic concentration analyzers and 

calculate the CH4 concentration following the requirements in paragraphs (g)(6)(i) through 

(g)(6)(iii) of this section.

(i) Use Method 25A or 25B at 40 CFR part 60, appendix A-7 to determine total gaseous 

organic concentration. You must calibrate the instrument with CH4 and determine the total 

gaseous organic concentration as carbon (or as CH4; K=1 in Equation 25A-1 of Method 25A at 

40 CFR part 60, appendix A-7).

(ii) Determine a non-methane organic carbon correction factor at the routine sampling 

location no less frequently than once a reporting year following the requirements in paragraphs 

(g)(6)(ii)(A) through (g)(6)(ii)(C) of this section.

(A) Take a minimum of three grab samples of the biogas with a minimum of 20 minutes 

between samples and determine the methane composition of the biogas using one of the methods 

specified in paragraphs (g)(1) through (g)(5) of this section.

(B) As soon as practical after each grab sample is collected and prior to the collection of a 

subsequent grab sample, determine the total gaseous organic concentration of the biogas using 

either Method 25A or 25B at 40 CFR part 60, appendix A-7 as specified in paragraph (g)(6)(i) of 

this section.

(C) Determine the arithmetic average methane concentration and the arithmetic average 

total gaseous organic concentration of the samples analyzed according to paragraphs 

(g)(6)(ii)(A) and (g)(6)(ii)(B) of this section, respectively, and calculate the non-methane organic 
carbon correction factor as the ratio of the average methane concentration to the average total 

gaseous organic concentration. If the ratio exceeds 1, use 1 for the non-methane organic carbon 

correction factor.

(iii) Calculate the CH4 concentration as specified in Equation II-8 of this section.

Where:

CCH4 = Methane (CH4) concentration in the biogas (volume %) for use in Equation II-4 of this 

subpart.

fNMOC = Non-methane organic carbon correction factor from the most recent determination of the 

non-methane organic carbon correction factor as specified in paragraph (g)(6)(ii) of 

this section (unitless).

CTGOC = Total gaseous organic carbon concentration measured using Method 25A or 25B at 40 

CFR part 60, appendix A-7 during routine monitoring of the biogas (volume %).

(h) For each anaerobic process (such as an anaerobic reactor, sludge digester, or lagoon) 

from which biogas is recovered, install, operate, maintain, and calibrate a gas flow meter capable 

of continuously measuring the volumetric flow rate of the recovered biogas using one of the 

methods specified in paragraphs (h)(1) through (h)(8) of this section or as specified by the 

manufacturer. Recalibrate each gas flow meter either biennially (every 2 years) or at the 

minimum frequency specified by the manufacturer. Except as provided in §98.353(c)(2)(iii), 

each gas flow meter must be capable of correcting for the temperature and pressure and, if 

necessary, moisture content.

(1) ASME MFC-3M-2004, Measurement of Fluid Flow in Pipes Using Orifice, Nozzle, and 

Venturi (incorporated by reference, see §98.7).
(2) ASME MFC-4M-1986 (Reaffirmed 1997), Measurement of Gas Flow by Turbine 

Meters (incorporated by reference, see §98.7).

(3) ASME MFC-6M-1998, Measurement of Fluid Flow in Pipes Using Vortex Flowmeters 

(incorporated by reference, see §98.7).

(4) ASME MFC-7M-1987 (Reaffirmed 1992), Measurement of Gas Flow by Means of 

Critical Flow Venturi Nozzles (incorporated by reference, see §98.7).

(5) ASME MFC-11M-2006 Measurement of Fluid Flow by Means of Coriolis Mass 

Flowmeters (incorporated by reference, see §98.7). The mass flow must be corrected to 

volumetric flow based on the measured temperature, pressure, and biogas composition.

(6) ASME MFC-14M-2003 Measurement of Fluid Flow Using Small Bore Precision 

Orifice Meters (incorporated by reference, see §98.7).

(7) ASME MFC-18M-2001 Measurement of Fluid Flow using Variable Area Meters 

(incorporated by reference, see §98.7).

(8) Method 2A or 2D at 40 CFR part 60, appendix A-1.

(i) All temperature, pressure, and, moisture content monitors required as specified in 

paragraph (f) of this section must be calibrated using the procedures and frequencies where 

specified by the device manufacturer, if not specified use an industry accepted or industry

standard practice.

(j) All equipment (temperature, pressure, and moisture content monitors and gas flow 

meters and gas composition monitors) must be maintained as specified by the manufacturer.

(k) If applicable, the owner or operator must document the procedures used to ensure the 

accuracy of measurements of COD or BOD5 concentration, wastewater flow rate, biogas flow 

rate, biogas composition, temperature, pressure, and moisture content. These procedures include, 
but are not limited to, calibration of gas flow meters, and other measurement devices. The 

estimated accuracy of measurements made with these devices must also be recorded, and the 

technical basis for these estimates must be documented.

§98.355 Procedures for estimating missing data.

A complete record of all measured parameters used in the GHG emissions calculations is 

required. Therefore, whenever a quality-assured value of a required parameter is unavailable 

(e.g., if a meter malfunctions during unit operation or if a required sample is not taken), a 

substitute data value for the missing parameter must be used in the calculations, according to the 

following requirements in paragraphs (a) through (c) of this section:

(a) For each missing weekly value of COD or BOD5 or wastewater flow entering an 

anaerobic wastewater treatment process, the substitute data value must be the arithmetic average 

of the quality-assured values of those parameters for the week immediately preceding and the 

week immediately following the missing data incident.

(b) For each missing value of the CH4 content or biogas flow rates, the substitute data value 

must be the arithmetic average of the quality-assured values of that parameter immediately 

preceding and immediately following the missing data incident.

(c) If, for a particular parameter, no quality-assured data are available prior to the missing 

data incident, the substitute data value must be the first quality-assured value obtained after the 

missing data period. If, for a particular parameter, the “after” value is not obtained by the end of 

the reporting year, you may use the last quality-assured value obtained “before” the missing data 

period for the missing data substitution. You must document and keep records of the procedures 

you use for all such estimates.

§98.356 Data reporting requirements.
In addition to the information required by §98.3(c), each annual report must contain the 

following information for each wastewater treatment system.

(a) Identify the anaerobic processes used in the industrial wastewater treatment system to 

treat industrial wastewater and industrial wastewater treatment sludge, provide a unique 

identifier for each anaerobic process, indicate the average depth in meters of each anaerobic 

lagoon, and indicate whether biogas generated by each anaerobic process is recovered. Provide a

description or diagram of the industrial wastewater treatment system, identifying the processes 

used, indicating how the processes are related to each other, and providing a unique identifier for 

each anaerobic process. Each anaerobic processes must be identified as one of the following:

(1) Anaerobic reactor.

(2) Anaerobic deep lagoon (depth more than 2 meters).

(3) Anaerobic shallow lagoon (depth less than 2 meters).

(4) Anaerobic sludge digester.

(b) For each anaerobic wastewater treatment process (reactor, deep lagoon, or shallow 

lagoon) you must report:

(1) Weekly average COD or BOD5 concentration of wastewater entering each anaerobic 

wastewater treatment process, for each week the anaerobic process was operated.

(2) Volume of wastewater entering each anaerobic wastewater treatment process for each 

week the anaerobic process was operated.

(3) Maximum CH4 production potential (B0) used as an input to Equation II-1 or II-2 of this 

subpart, from Table II-1 to this subpart.

(4) Methane conversion factor (MCF) used as an input to Equation II-1 or II-2 of this 

subpart, from Table II-1 to this subpart.
(5) Annual mass of CH4 generated by each anaerobic wastewater treatment process, 

calculated using Equation II-1 or II-2 of this subpart.

(6) If the facility performs an ethanol production processing operation as defined in §98.358 

of this subpart, you must indicate if the facility uses a wet milling process or a dry milling 

process.

(c) For each anaerobic wastewater treatment process from which biogas is not recovered, 

you must report the annual CH4 emissions, calculated using Equation II-3 of this subpart.

(d) For each anaerobic wastewater treatment process and anaerobic sludge digester from 

which some biogas is recovered, you must report:

(1) Annual quantity of CH4 recovered from the anaerobic process calculated using Equation 

II-4 of this subpart.

(2) Total weekly volumetric biogas flow for each week (up to 52 weeks/year) that biogas is 

collected for destruction.

(3) Weekly average CH4 concentration for each week that biogas is collected for 

destruction.

(4) Weekly average biogas temperature for each week at which flow is measured for biogas 

collected for destruction, or statement that temperature is incorporated into monitoring 

equipment internal calculations.

(5) Whether flow was measured on a wet or dry basis, whether CH4 concentration was 

measured on a wet or dry basis, and if required for Equation II-4 of this subpart, weekly average 

moisture content for each week at which flow is measured for biogas collected for destruction, or 

statement that moisture content is incorporated into monitoring equipment internal calculations.
(6) Weekly average biogas pressure for each week at which flow is measured for biogas 

collected for destruction, or statement that pressure is incorporated into monitoring equipment 

internal calculations.

(7) CH4 collection efficiency (CE) used in Equation II-5 of this subpart.

(8) Whether destruction occurs at the facility or off-site. If destruction occurs at the facility, 

also report whether a back-up destruction device is present at the facility, the annual operating 

hours for the primary destruction device, the annual operating hours for the back-up destruction 

device (if present), the destruction efficiency for the primary destruction device, and the 

destruction efficiency for the back-up destruction device (if present).

(9) For each anaerobic process from which some biogas is recovered, you must report the 

annual CH4 emissions, as calculated by Equation II-6 of this subpart.

(e) The total mass of CH4 emitted from all anaerobic processes from which biogas is not 

recovered (calculated in Equation II-3 of this subpart) and from all anaerobic processes from 

which some biogas is recovered (calculated in Equation II-6 of this subpart) using Equation II-7 

of this subpart.

§98.357 Records that must be retained.

In addition to the information required by §98.3(g), you must retain the calibration records 

for all monitoring equipment, including the method or manufacturer's specification used for 

calibration.

§98.358 Definitions.

Except as provided below, all terms used in this subpart have the same meaning given in the 

CAA and subpart A of this part.
Biogas means the combination of CO2, CH4, and other gases produced by the biological 

breakdown of organic matter in the absence of oxygen.

Dry milling means the process in which shelled corn is milled by dry process, without an 

initial steeping step.

Ethanol production means an operation that produces ethanol from the fermentation of 

sugar, starch, grain, or cellulosic biomass feedstocks, or the production of ethanol synthetically 

from petrochemical feedstocks, such as ethylene or other chemicals.

Food processing means an operation used to manufacture or process meat, poultry, fruits, 

and/or vegetables as defined under NAICS 3116 (Meat Product Manufacturing) or NAICS 3114 

(Fruit and Vegetable Preserving and Specialty Food Manufacturing). For information on NAICS 

codes, see http://www.census.gov/eos/www/naics/.

Industrial wastewater means water containing wastes from an industrial process. Industrial 

wastewater includes water which 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.

Industrial wastewater treatment sludge means solid or semi-solid material resulting from 

the treatment of industrial wastewater, including but not limited to biosolids, screenings, grit, 

scum, and settled solids.

Wastewater treatment system means the collection of all processes that treat or remove 

pollutants and contaminants, such as soluble organic matter, suspended solids, pathogenic 

organisms, and chemicals from wastewater prior to its reuse or discharge from the facility.
Wet milling means the process in which shelled corn is steeped in a dilute solution of 

sulfurous acid (sulfur dioxide dissolved in water) prior to further processing.

Weekly average means the sum of all values measured in a calendar week divided by the 

number of measurements.

Table II-1 to Subpart II of Part 98—Emission Factors

Factors Default value Units

B0—for facilities monitoring COD 0.25 Kg CH4/kg COD

B0—for facilities monitoring BOD5 0.60 Kg CH4/kg BOD5

MCF—anaerobic reactor 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.

Table II-2 to Subpart II—Collection Efficiencies of Anaerobic Processes

Anaerobic process type Cover type

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