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ENVIRONMENTAL PROTECTION AGENCY
Environmental Protection Agency
CFR Citation: 40 CFR Part 63
RIN ID: RIN 2060-AE-94
OAR ID: [OAR-2003-0191; FRL-7780-7]
NOTICE: PROPOSED RULES
ACTION: Air pollutants, hazardous; national emission standards:
DOCUMENT ACTION: Proposed rule; amendments.
SUBJECT CATEGORY:
Biodegraded (F
DATES: Comments. Comments must be received on or before August 30, 2004.
Public Hearing. If anyone contacts EPA requesting to speak at a public hearing by July 20, 2004, a public hearing will be held on July 30, 2004. Persons interested in presenting oral testimony or inquiring as to whether a hearing is to be held should contact JoLynn Collins, Waste and Chemical Processes Group, Emissions Standards Division (C439 03), U.S. EPA, Research Triangle Park, NC 27711, telephone (919) 541 5671 at least 2 days in advance of the public hearing.
DOCUMENT SUMMARY: This action proposes amendments to appendix C to 40 CFR part
63. Appendix C defines the procedures for an owner or operator of a
facility that generates wastewater to calculate the sitespecific
fraction of organic compounds biodegraded (F
SUMMARY: Biological treatment unit; determination of fraction biodegraded (Fbio),
SUPPLEMENTAL INFORMATION
Regulated Entities. The proposed amendments could possibly apply to a large number of industries that could be using the provisions of 40 CFR part 63, appendix C, to demonstrate compliance with an air standard. Therefore, we have not listed specific affected industries or their North American Industrial Classification System (NAICS) codes here. If you have any questions regarding the applicability of this action to a particular entity, consult the person listed in the preceding FOR FURTHER INFORMATION CONTACT section. Outline. The information presented in the preamble is organized as follows:
I. Background
II. Summary of the Proposed Amendments
III. Statutory and Executive Order Reviews
A. Executive Order 12866, Regulatory Planning and Review
B. Paperwork Reduction Act
C. Regulatory Flexibility Act
D. Unfunded Mandates Reform Act
E. Executive Order 13132, Federalism
[[Page 39384]]
F. Executive Order 13175, Consultation and Coordination with Indian Tribal Governments
G. Executive Order 13045, Protection of Children from Environmental Health & Safety Risks
H. Executive Order 13211, Actions Concerning Regulations that Significantly Affect Energy Supply, Distribution, or Use
I. National Technology Transfer Advancement Act
I. Background
Appendix C to 40 CFR part 63 provides procedures for calculating
F
Wastewater streams from SOCMI processes can contain hundreds of
organic wastewater compounds (OWWC). For these wastewater streams,
identifying all (or the predominant constituents) of the OWWC would
require costly analytical testing. To provide for a more costeffective
evaluation of wastewater streams with multiple OWWC, the proposed
amendments to appendix C to 40 CFR part 63 add a procedure for
determining an overall F
II. Summary of the Proposed Amendments
The proposed amendments to appendix C to 40 CFR part 63 add a non speciated, aerated draft tube reactor test to the existing batch test procedures described in section III.D of appendix C. The proposed non speciated test procedure uses the same approach as the aerated reactor test, but also includes procedures that are related to evaluating individual components in a wastewater stream without having to identify these components or make separate measurements of the characteristics of the components.
The proposed test procedure relies on establishing correlations between peak areas of unidentified compounds resulting from gas chromatography (GC) analysis with the measured concentrations of the unidentified compounds in the draft tube headspace. Automated gas sampling or solid phase microextraction (SPME) fibers are used to collect samples of the gas in the headspace of the draft tube over the time period of the test. Compounds in the gas samples are measured using a gas chromatography/flame ionization detector (GC/FID).
The change in each VOC concentration in the headspace of the draft
tube is related to the decrease in aqueous phase concentration of each
VOC over time. This correlation is used to calculate biodegradation
rates for each VOC. Also, an overall F
Today's proposed nonspeciated aerated draft tube reactor test
method is an appropriate addition to appendix C to 40 CFR part 63 to
provide a more costeffective option for compliance demonstrations for
activated sludge biological treatment units affected by wastewater
rules regulating VOC. While we consider this to be a costeffective
option, the nonspeciated method also provides an accurate procedure
for demonstrating biodegradation as opposed to volatilization for an
activated sludge biological unit. Although appropriate for rules such
as the proposed SOCMI Wastewater NSPS that would regulate OWWC, the
nonspeciated aerated method may not be appropriate for other rules. In
the case of the proposed SOCMI Wastewater NSPS, the regulated
pollutants would be OWWC which comprise all of the organic compounds in
the wastewater streams that may volatilize, i.e., compounds with a
Henry's law constant greater than 0.1 atmosphere per mole fraction. For
rules requiring destruction of hazardous air pollutants (HAP), other
appendix C procedures are preferred because they require identification
and quantification of HAP, ensuring the overall F
In addition to the nonspeciated aerated draft tube reactor test,
the proposed amendments also make minor revisions to clarify the
existing batch test procedures in section III.D of appendix C to 40 CFR
part 63. We are clarifying that the batch test procedures are headspace
characterization methods. Also, we are clarifying that the equilibrium
verification required by the aerated reactor test must be demonstrated
for one or more of the most volatile compounds to be tested for biodegradation.
III. Statutory and Executive Order Reviews
A. Executive Order 12866, Regulatory Planning and Review
Under Executive Order 12866 (58 FR 51735, October 4, 1993), EPA
must determine whether the regulatory action is ``significant'' and,
therefore, subject to review by the OMB and the requirements of the
Executive Order. The Executive Order defines ``significant regulatory
action'' as one that is likely to result in a rule that may:
(1) Have an annual effect on the economy of $100 million or more or
adversely affect in a material way the economy, a sector of the
economy, productivity, competition, jobs, the environment, public
health or safety, or State, local, or tribal governments or communities;
(2) create a serious inconsistency or otherwise interfere with an action taken or planned by another agency;
(3) materially alter the budgetary impact of entitlements, grants,
user fees, or loan programs, or the rights and obligations of recipients thereof; or
(4) raise novel legal or policy issues arising out of legal
mandates, the President's priorities, or the principles set forth in the Executive Order.
We have determined that the proposed amendments are not a ``significant regulatory action'' under the terms of Executive Order 12866 and do not impose any additional control requirements. The proposed amendments add an additional, potentially lesscostly option for compliance demonstration for certain biological treatment units. Therefore, the proposed amendments are not subject to review by OMB. B. Paperwork Reduction Act
The proposed amendments to appendix C to 40 CFR part 63 do not
impose or change any information collection requirements. Therefore,
the requirements of the Paperwork Reduction Act do not apply to the proposed amendments.
[[Page 39385]]
C. Regulatory Flexibility Act
The Regulatory Flexibility Act generally requires an agency to prepare a regulatory flexibility analysis of any rule subject to notice and comment rulemaking requirements under the Administrative Procedure Act or any other statute unless the agency certifies that the rule will not have a significant impact on a substantial number of small entities. Small entities include small businesses, small government organizations, and small government jurisdictions.
For purposes of assessing the impacts of today's rule on small entities, small entity is defined as: (1) A small business with up to 1,000 employees; (2) a small governmental jurisdiction that is a government of a city, county, town, school district or special district with a population of less than 50,000; and (3) a small organization that is any notforprofit enterprise which is independently owned and operated and is not dominant in its field.
After considering the economic impacts of today's proposed rule on small entities, I certify that this action will not have a significant economic impact on a substantial number of small entities. Today's proposed amendments do not increase the cost of compliance because: (1) The proposed amendments do not impose requirements independent of the proposed SOCMI Wastewater NSPS; (2) we proposed using appendix C to 40 CFR part 63 to demonstrate compliance with the proposed SOCMI Wastewater NSPS in the supplement to the proposed rule; (3) the cost of compliance demonstrations is accounted for in the proposed SOCMI Wastewater NSPS; and (4) the procedure we are proposing to add to appendix C provides another, less expensive, alternative to the procedures currently available in appendix C. We continue to be interested in the potential impacts of the proposed rule on small entities and welcome comments on issues related to such impacts. D. Unfunded Mandates Reform Act
Title II of the Unfunded Mandates Reform Act of 1995 (URMA), Public Law 1044, establishes requirements for Federal agencies to assess the effects of their regulatory actions on State, local, and tribal governments and the private sector. Under section 202 of the UMRA, the EPA generally must prepare a written statement, including a cost benefit analysis, for proposed and final rules with ``Federal mandates'' that may result in expenditures by State, local, and tribal governments, in the aggregate, or by the private sector, of $100 million or more in any 1 year. Before promulgating an EPA rule for which a written statement is needed, section 205 of the UMRA generally requires EPA to identify and consider a reasonable number of regulatory alternatives and adopt the least costly, most costeffective, or least burdensome alternative that achieves the objectives of the rule. The provisions of section 205 do not apply when they are inconsistent with applicable law. Moreover, section 205 allows EPA to adopt an alternative other than the least costly, most costeffective, or least burdensome alternative if the Administrator publishes with the final rule an explanation why that alternative was not adopted. Before EPA establishes any regulatory requirements that may significantly or uniquely affect small governments, including tribal governments, it must have developed, under section 203 of the UMRA, a small government agency plan. The plan must provide for notifying potentially affected small governments, enabling officials of affected small governments to have meaningful and timely input in the development of EPA's regulatory proposals with significant Federal intergovernmental mandates, and informing, educating, and advising small governments on compliance with the regulatory requirements.
The EPA has determined that the proposed amendments do not contain a Federal mandate that may result in expenditures of $100 million or more for State, local, and tribal governments, in the aggregate, or the private sector in any 1 year. Thus, the proposed amendments are not subject to the requirements of section 202 and 205 of the UMRA. In addition, EPA has determined that the proposed amendments do not contain regulatory requirements that might significantly or uniquely affect small governments because the proposed amendments do not impose any additional regulatory requirements. Therefore, the proposed amendments are not subject to the requirements of section 203 of the UMRA.
E. Executive Order 13132, Federalism
Executive Order 13132 (64 FR 43255, August 10, 1999) requires EPA to develop an accountable process to ensure ``meaningful and timely input by State and local officials in the development of regulatory policies that have federalism implications.'' ``Policies that have federalism implications'' is defined in the Executive Order to include regulations that have ``substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.''
The proposed amendments do not have federalism implications. The
proposed amendments will not have substantial direct effects on the
States, on the relationship between the national government and the
States, or on the distribution of power and responsibilities among the
various levels of government, as specified in Executive Order 13132.
The proposed amendments will not impose substantial direct compliance
costs on State or local governments, and they will not preempt State
law. Thus, Executive Order 13132 does not apply to the proposed amendments.
F. Executive Order 13175, Consultation and Coordination With Indian Tribal Governments
Executive Order 13175 (65 FR 67249, November 9, 2000) requires EPA to develop an accountable process to ensure ``meaningful and timely input by tribal officials in the development of regulatory policies that have tribal implications.''
The proposed amendments do not have tribal implications and will
not have substantial direct effects on tribal governments, on the
relationship between the Federal government and Indian tribes, or on
the distribution of power and responsibilities between the Federal
government and Indian tribes. Thus, Executive Order 13175 does not apply to the proposed amendments.
G. Executive Order 13045, Protection of Children From Environmental Health & Safety Risks
Executive Order 13045 (62 FR 19885, April 23, 1997) applies to any rule that (1) is determined to be ``economically significant'' as defined under Executive Order 12866, and (2) concerns an environmental health or safety risk that EPA has reason to believe may have a disproportionate effect on children. If the regulatory action meets both criteria, the EPA must evaluate the environmental health or safety effects of the planned rule on children, and explain why the planned regulation is preferable to other potentially effective and reasonably feasible alternatives considered by EPA.
The EPA interprets Executive Order 13045 as applying only to those
regulatory actions that are based on health or safety risks, such that
the analysis required under section 5501 of the Executive Order has
the potential to influence the rule. The proposed amendments are not subject to
[[Page 39386]]
Executive Order 13045 because they are based on technology performance
and not on health and safety risks. Also, the proposed amendments are not ``economically significant.''
H. Executive Order 13211, Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use
The proposed amendments are not subject to Executive Order 13211 (66 FR 28355, May 22, 2001) because they are not a significant regulatory action under Executive Order 12866 and because they will not have an adverse effect on the supply, distribution, or use of energy. I. National Technology Transfer Advancement Act
Section 12(d) of the National Technology Transfer and Advancement Act (NTTAA) of 1995, (Public Law 104113; 15 U.S.C. 272 note) directs EPA to use voluntary consensus standards in their regulatory and procurement activities unless to do so would be inconsistent with applicable law or otherwise impractical. Voluntary consensus standards are technical standards (e.g., material specifications, test methods, sampling procedures, business practices) developed or adopted by one or more voluntary consensus bodies. The NTTAA directs EPA to provide Congress, through annual reports to OMB, with explanations when an agency does not use available and applicable voluntary consensus standards.
The proposed amendments include technical standards and requirements for taking measurements. Consistent with the NTTAA, we conducted searches for applicable voluntary consensus standards that could be used in addition to the method proposed in this action by searching the National Standards System Institute (NSSN) database. We searched for methods and tests required by the proposed amendments, all of which are methods or tests previously promulgated. No potentially equivalent methods for the methods and tests in the proposal were found in the NSSN database search. Therefore, we do not propose to use any voluntary consensus standards. The search and review results are documented in Dockets No. OAR20030191 and A9432.
List of Subjects in 40 CFR Part 63
Environmental protection, Administrative practice and procedure,
Air pollution control, Hazardous substances, Intergovernmental relations, Reporting and recordkeeping requirements.
Dated: June 24, 2004.
Michael O. Leavitt,
Administrator.
For reasons cited in the preamble, title 40, chapter I, part 63 of the Code of Federal Regulations is proposed to be amended as follows: PART 63[AMENDED]
1. The authority citation for part 63 continues to read as follows:
Authority: 42 U.S.C. 7401 et seq.
2. Appendix C is amended by revising Section III Procedures for
Determination of F
* * * * *
III. Procedures for Determination of F
* * * * *
Procedure 4 explains three types of batch tests which may be used to estimate the first order biodegradation rate constant. * * * * * * * *
3. Appendix C is amended by revising section III.D to read as follows:
D. Batch Tests (Procedure 4)
Three types of batch tests which may be used to determine kinetic parameters are: (1) The aerated reactor test, (2) the sealed reactor test, and (3) the nonspeciated aerated draft tube reactor test. The nonspeciated aerated draft reactor test is appropriate for compliance demonstrations with rules that regulate volatile organic compounds (VOC). Where there is a limited specific list of HAP compounds of concern one of the other batch tests or procedures is preferable. The aerated reactor test is also known as the BOX test (batch test with oxygen addition). The sealed reactor test is also known as the serum bottle test. These batch tests should be conducted only by persons familiar with procedures for determining biodegradation kinetics. Detailed discussions of batch procedures for determining biodegradation kinetic parameters can be found in references 14. A detailed discussion of the nonspeciated aerated draft tube reactor test can be found in reference 9.
For the batch test approaches, a biomass sample from the
activated sludge unit of interest is collected, aerated, and stored
for no more than 4 hours prior to testing. To collect sufficient
data when biodegradation is rapid, it may be necessary to dilute the
biomass sample. If the sample is to be diluted, the biomass sample
shall be diluted using treated effluent from the activated sludge
unit of interest to a concentration such that the biodegradation
test will last long enough to make at least six concentration
measurements. It is recommended that the tests not be terminated until the compound concentration falls below the limit of
quantitation (LOQ). Measurements that are below the LOQ should not
be used in the data analysis. Biomass concentrations shall be
determined using standard methods for measurement of mixed liquor volatile suspended solids (MLVSS) (reference 5).
The change in concentration of a test compound may be monitored by either measuring the concentration in the liquid or in the reactor headspace. The analytical technique chosen for the test should be as sensitive as possible. For the batch test procedures using headspace characterization described in this section, equilibrium conditions must exist between the liquid and gas phases of the experiments because the data analysis procedures are based on this premise. To use the headspace sampling approach, the reactor headspace must be in equilibrium with the liquid so that the headspace concentrations can be correlated with the liquid concentrations. Before the biodegradation testing is conducted using headspace analysis, the equilibrium assumption must be verified. A discussion of the equilibrium assumption verification is given below in sections D.1 and D.2 since different approaches are required for the two types of batch tests.
To determine biodegradation kinetic parameters in a batch test,
it is important to choose an appropriate initial substrate
(compound(s) of interest) concentration for the test. The outcome of
the batch experiment may be influenced by the initial substrate
(S
S
[GRAPHIC] [TIFF OMITTED] TP30JN04.016
Where:
S
S
X = biomass concentration in the batch test (g MLVSS/liter) 1.42 = Conversion factor to convert to COD units
For the batch tests described in this section, the
S
1. Aerated Reactor Test. An aerated draft tube reactor may be
used for the biokinetics testing (as an example see Figure 2 of
appendix C). Other aerated reactor configurations may also be used.
Air is bubbled through a porous frit at a rate sufficient to aerate
and keep the reactor uniformly mixed. Aeration rates typically vary
from 50 to 200 milliter per minute (ml/min) for a 1 liter system. A
mass flow rate controller is used to carefully control the air flow
rate because it is important to have an accurate measure of this
rate. The dissolved oxygen (DO) concentration in the system must not fall below 2 milligram per liter (mg/liter) so that the
biodegradation observed will
[[Page 39387]]
not be DOlimited. Once the air flow rate is established, the test
mixture (or compound) of interest is then injected into the reactor
and the concentration of the compound(s) is monitored over time.
Concentrations may be monitored in the liquid or in the headspace. A
minimum of six samples shall be taken over the period of the test.
However, it is recommended to collect samples until the compound
concentration falls below the LOQ. If liquid samples are collected,
they must be small enough such that the liquid volume in the batch reactor does not change by more than 10 percent.
Before conducting experiments with biomass, it is necessary to
verify the equilibrium assumption using one or more of the more
volatile components from the list of volatile components that will
be tested. A demonstration of equilibrium with the most volatile components that will be tested is expected to assure that
equilibrium is also achieved with the less volatile components. The
number of volatile components needed to demonstrate equilibrium
depends on experimental uncertainty, literature measurement
uncertainty, and the availability of previous demonstrations of equilibrium using similar equipment. If the most volatile
component(s) that will be tested have a Henry's constant of less
than 0.1 (y/x), then a demonstration of equilibrium with those components is not required if a previous demonstration of
equilibrium is available using similar equipment. The equilibrium
assumption can be verified by conducting a stripping experiment
using the effluent (no biomass) from the activated sludge unit of
interest. Effluent is filtered with a 0.45 micrometer (um) or
smaller filter and placed in the draft tube reactor. Air is sparged
into the system and the compound concentration in the liquid or
headspace is monitored over time. This test with no biomass will
provide an estimate of the Henry's law constant. If the system is at
equilibrium, the Henry's law constant may be estimated with the following equation:
ln(C/C
Where:
C = concentration at time, t (min)
C
G = volumetric gas flow rate (ml/min)
V = liquid volume in the batch reactor (ml)
K
A plot of ln(C/C
The concentration of a compound decreases in the bioreactor due
to both biodegradation and stripping. Biodegradation processes are
typically described with a Monod model. This model and a stripping
expression are combined to give a mass balance for the aerated draft tube reactor:
[GRAPHIC] [TIFF OMITTED] TP30JN04.007
Where:
s = test compound concentration, mg/liter
G = volumetric gas flow rate, liters/hr
K
V = volume of liquid in the reactor, liters
X = biomass concentration (g MLVSS/liter)
Q
Equation App. C3 can be integrated to obtain the following equation:
[GRAPHIC] [TIFF OMITTED] TP30JN04.008
where:
A = GK
B = GK
S
This equation is used along with the substrate concentration
versus time data to determine the best fit parameters (Q
K
The compoundspecific biorate constants are then measured using
Form XII. The stripping constant that was determined from Form XI
and a headspace correction factor of 1 are entered on Form XII. The
aerated reactor biotest may then be run, measuring concentrations of
each compound of interest as a function of time. If headspace
concentrations are measured instead of liquid concentrations, then
the corresponding liquid concentrations are calculated from the
headspace measurements using the K
The concentration data on Form XII may contain scatter that can adversely influence the data interpretation. It is acceptable to curve fit the concentration data and enter the concentrations on the fitted curve instead of the actual data. If curve fitting is used, the curvefitting procedure must be based upon the Equation App. C 4. When curve fitting is used, it is necessary to attach a plot of the actual data and the fitted curve to Form XII.
If the stripping rate constant is relatively large when compared
to the biorate at low concentrations, it may be difficult to obtain
accurate evaluations of the firstorder biorate constant. In these
cases, either reducing the stripping rate constant by lowering the
aeration rate, or increasing the biomass concentrations should be
considered. The final result of the batch testing is the measurement
of a biorate that can be used to estimate the fraction biodegraded,
f
2. Sealed Reactor Test. This test uses a closed system to
prevent losses of the test compound by volatilization. This test may
be conducted using a serum bottle or a sealed draft tube reactor
(for an example see Figure 3 of appendix C). Since no air is
supplied, it is necessary to ensure that sufficient oxygen is
present in the system. The DO concentration in the system must not
fall below 2 mg/liter so that the biodegradation observed will not be DOlimited. As an
[[Page 39388]]
alternative, oxygen may be supplied by electrolysis as needed to
maintain the DO concentration above 2 mg/liter. The reactor contents
must be uniformly mixed, by stirring or agitation using a shaker or
similar apparatus. The test mixture (or compound) of interest is
injected into the reactor and the concentration is monitored over
time. A minimum of six samples shall be taken over the period of the
test. However, it is necessary to monitor the concentration until it falls below the LOQ.
The equilibrium assumption must be verified for the batch
reactor system that depends on headspace characterization. In this
case, K
The concentration of a compound decreases in the bioreactor due to biodegradation according to Equation App. C5:
[GRAPHIC] [TIFF OMITTED] TP30JN04.009
where:
s = test compound concentration (mg/liters)
V
K
t = time (hours)
X = biomass concentration (g MLVSS/liter)
S
Equation App. C5 can be solved analytically to give: [GRAPHIC] [TIFF OMITTED] TP30JN04.010
This equation is used along with the substrate concentration
versus time data to determine the best fit parameters (Q
If the sealed reactor test is used, Form X is used to determine
the headspace correction factor. The disappearance of a compound in
the sealed reactor test is slowed because a fraction of the compound
is not available for biodegradation because it is present in the
headspace. If the compound is almost entirely in the liquid phase,
the headspace correction factor is approximately one. If the
headspace correction factor is substantially less than one, improved
mass transfer or reduced headspace may improve the accuracy of the
sealed reactor test. A preliminary sealed reactor test must be
conducted to test the equilibrium assumption. As the compound of
interest is degraded, simultaneous headspace and liquid samples should be collected and Form X should be used to evaluate
K
The compoundspecific biorate constants are then calculated
using Form XII. For the sealed reactor test, a stripping rate
constant of zero and the headspace correction factor that was
determined from Form X are entered on Form XII. The sealed reactor
test may then be run, measuring the concentrations of each compound
of interest as a function of time. If headspace concentrations are
measured instead of liquid concentrations, then the corresponding
liquid concentrations are calculated from the headspace measurements using K
The concentration data on Form XII may contain scatter that can adversely influence the data interpretation. It is acceptable to curve fit the concentration data and enter the concentrations on the fitted curve instead of the actual data. If curve fitting is used, the curvefitting procedure must be based upon Equation App. C6. When curve fitting is used, it is necessary to attach a plot of the actual data and the fitted curve to Form XII.
If a sealed collapsible reactor is used that has no headspace, the headspace correction factor will equal 1, but the stripping rate constant may not equal 0 due to diffusion losses through the reactor wall. The ratio of the rate of loss of compound to the concentration of the compound in the reactor (units of per hour) must be evaluated. This loss ratio has the same units as the stripping rate constant and may be entered as the stripping rate constant on line 1 of Form XII.
If the loss due to diffusion through the walls of the collapsible reactor is relatively large when compared to the biorate at low concentrations, it may be difficult to obtain accurate evaluations of the firstorder biorate constant. In these cases, either replacing the materials used to construct the reactor with materials of low permeability or increasing the biomass
concentration should be considered.
The final result of the batch testing is the measurement of a
biorate that can be used to estimate the fraction biodegraded,
f
The number on Form XII line 9 will equal the Monod firstorder biorate constant if the fullscale system is operated in the first order range. If the fullscale system is operated at concentrations above that of the Monod firstorder range, the value of the number on line 9 will be somewhat lower than the Monod firstorder biorate constant. With supporting biorate data, the Monod model used in Form XII may be used to estimate the effective biorate constant K1 for use in Form III.
If a reactor with headspace is used, analysis of the data using
Equation App. C6 is valid only if V
If there is no headspace (e.g., a collapsible reactor), Equation App. C6 is independent of V
restrictions on the liquid volume. If a membrane or bag is used as
the collapsiblevolume reactor, it may be important to monitor for
diffusion losses in the system. To determine if there are losses,
the bag should be used without biomass and spiked with the
compound(s) of interest. The concentration of the compound(s) in the
reactor should be monitored over time. The data are analyzed as described above for the sealed reactor test.
3. Nonspeciated aerated draft tube reactor test. This method is
appropriate for compliance demonstrations with rules that regulate
VOC. The aerated draft tube reactor test is used for assessing the
F
[[Page 39389]]
with the nonspeciated draft tube test, with the exception of
special procedures that are related to the limited information
available for identifying the waste components, the volatility of
the components, and the amount of the components that are present in
the waste. The nonspeciated test method described here is based
upon evaluating individual components in a waste without the need to
identify the name of the component or make separate measurements of the characteristics of the components.
3.1 Purpose of the method. The following sections identify specific purposes for which the nonspeciated method is used. For each purpose identified in sections 3.1.1 through 3.1.6, a correlation between the peak area of the compound in the GC analysis and the concentration in the draft tube headspace must be available as discussed in section 3.10.
3.1.1 Henry's law constant for each nonspeciated organic compound. One run of the nonspeciated method without biomass is used to obtain estimates of the Henry's law value for each individual organic compound identified in the waste. For each volatile organic component, correlations of the vapor phase concentration and the stripping times are developed. A Henry's law value is determined for each component. See section 3.6.
3.1.2 Nonspeciated organic compound concentration. One run of the nonspeciated method without biomass is used to evaluate the individual organic compound concentrations in the waste. The amount of each component initially present in the waste is determined from the Henry's law value and the correlation between the peak area and the gas correlation. See section 3.9.
3.1.3 Total concentration of nonspeciated organic compounds. One run of the nonspeciated method without biomass is used to obtain estimates of the individual organic compound concentrations in the waste. These individual concentrations are summed to obtain the total concentration of organic compounds. See section 3.11.
3.1.4 Biodegradation rate for each nonspeciated organic
compound. Two runs of the nonspeciated method, one with biomass and one without biomass are used to obtain estimates of the
biodegradation rate for each individual organic compound identified in the waste. The stripping rates from the run without
biodegradation is compared to the air stripping run with
biodegradation. The difference in the rates of removal in the two
runs is used to calculate the biodegradation rate. See section 3.7.
3.1.5 Individual values of f
3.1.6 Overall F
These individual F
A weighted summation of these individual estimates of biological and air emission removal is used to obtain an overall
F
3.2 Reactor configuration. An aerated draft tube reactor is used for the biokinetics testing for the nonspeciated reactor test (as an example see Figure 2 of appendix C). Other aerated reactor configurations may also be used if equivalent to the aerated draft tube reactor. Air is bubbled through a porous frit at a rate sufficient to aerate and keep the reactor uniformly mixed. A discussion of the setup and the operation of the aerated draft tube reactor is presented in Section D.1.
3.3 Reactor sampling. Concentrations of volatile compounds are
only monitored in the headspace in the nonspeciated aerated draft
tube reactor test. The headspace may be monitored with solid phase
microextraction (SPME) fibers or with automated gas sampling. A
minimum of six headspace samples shall be taken over the period of
the test for each individual run and analyzed by gas chromatography.
Sufficient gas samples will be taken to provide at least 3 data
samples for each relevant component for each air stripping run. It is necessary to collect enough samples to quantify the
characteristics of the individual volatile compound peaks in the
system; therefore, in some cases it is possible to reduce the total
number of headspace samples by sampling more frequently at the beginning of the run.
3.4 Reactor equilibrium verification. It is necessary to verify the equilibrium assumption for the nonspeciated aerated draft tube reactor test as discussed in section D.1, using Equation C2.
A plot of ln(C/C
characterization of nonspeciated peaks. Nonspeciated compound
peaks that demonstrate Henry's law constants less than 0.1 (y/x) in
the test are excluded from the analysis. If the aerated draft tube
reactor cannot be demonstrated to be at equilibrium, modify the reactor design and/or operation.
3.5 Two reactor runs. The concentration of a compound in the
bioreactor is measured in the headspace in two different runs, first
with air stripping only and then second with both biodegradation and
air stripping. A first order biodegradation rate model is used to
model the biodegradation in the aerated draft tube reactor. Since
the measurement of the first order biodegradation rate constant is a
function of concentration, it is important to have concentrations of
nonspeciated compounds in this test that closely represent the
conditions in the fullscale biodegradation unit that you are
evaluating. Since the components and concentrations are generally
unknown for this nonspeciated method, samples of actual wastewater
should be obtained from the applicable location in the fullscale
facility, or as close to these conditions as practicable, such as a
sample of wastewater from a pilot plant, a fullscale process from
another site, etc. This model and a stripping expression are
combined to give a mass balance for the aerated draft tube reactor: [GRAPHIC] [TIFF OMITTED] TP30JN04.011
where:
s = test compound concentration, mg/liter
G = volumetric gas flow rate, liters/hr
K
V = volume of liquid in the reactor, liters
X = biomass concentration (g MLVSS/liter)
K
Equation App. C7 can be integrated to obtain the following equation:
[[Page 39390]]
[GRAPHIC] [TIFF OMITTED] TP30JN04.012
where:
Peakarea
Peakarea
GK
K
If ln(Peakarea) is plotted on the y axis and t is plotted on the
x axis, the data should form a straight line with a slope that
equals the negative of the terms in parenthesis on the right of
Equation App. C8 and the intercept of this line on the y axis equals ln (Peakarea
A discussion of Equation App. C8 is provided in reference 9. This equation is used to analyze the two stripping runs, with and without biodegradation. Evaluate the slope for each nonspeciated peak for both the run without biodegradation and the run with biodegradation.
3.6 Henry's law constants. To evaluate the Henry's law constant
for each unspeciated VOC, you obtain the slope for the run without
biodegradation and then equate this slope (with a negative value) to
GK
3.7 Biodegradation rate constant. To evaluate the first order
biorate constant, use the slope for each nonspeciated peak for the
run without biodegradation and subtract the corresponding slope of
the nonspeciated peak with biodegradation. This difference equals
K
3.8 Accuracy concerns. The nonspeciated compound peak data may contain scatter that can adversely influence the data
interpretation. In the case of significant data scatter for a
specific compound that will limit the ability to determine the
difference in slopes from the two runs, it is possible to use
conventional statistics to estimate the accuracy of the difference
in slopes. When it is not possible to demonstrate a significant
difference in the slopes of the two runs for a nonspeciated
compound, the value of K
K
If the stripping rate constant is relatively large when compared to the biorate, it may be difficult to obtain an accurate evaluation of the firstorder biorate constant. In these cases, either reducing the stripping rate constant by lowering the aeration rate, or increasing the biomass concentrations should be considered. If the aeration rate is changed, the equilibrium assumption will have to be verified again. Equilibrium conditions are typically more difficult to obtain at greater aeration rates, but lower aeration rates could result in difficulty in achieving equilibrium conditions due to poorer mixing.
3.9 The concentration of each compound. The amount of each
individual nonspeciated organic compound is calculated by measuring
the initial area of the chromatographic peak of the individual
compound, Peakarea
The equation used for the SPME method is as follows: [GRAPHIC] [TIFF OMITTED] TP30JN04.013
where:
C
P
K
K
F = the ratio of the peak area to the mass on the extraction fiber, (area counts/mg).
The equation used for the automatic headspace sampling alternative is as follows:
[GRAPHIC] [TIFF OMITTED] TP30JN04.014
where the symbols are defined above, and Fc is the ratio of the peak
area count to the concentration in the gas phase, (mg/L). This number depends on the sampling and analysis setup.
3.10 SPME fiber partition correlation. If automatic gas sampling is used, it is not necessary to account for SPME fiber partition effects, but it is necessary to use gas chromatographic calibration factors for the compounds of interest. Reference 9 presents additional details on the use of gas chromatographic calibration factors and SPME fiber partition factors.
The SPME fiber partition factor is obtained by preparing an
aqueous solution or solutions with known compounds of varying
volatility and chemical characteristics that are representative of
the waste stream of concern. The detector peak areas and retention
times are then obtained with the SPME method for these known
compounds. The mass of compound is calculated from the area counts
of the GC compound peak, and the concentration in the headspace is
calculated from the Henry's law factor and the known liquid
concentration. The fiber partition factor K
The SPME fiber partition factor correlation for a series of petrochemical compounds that is provided in Figure 4 of reference 9 can be used with verification of the correlation with a few compounds if the chemicals in that correlation are representative of the waste stream of concern. The fiber recovery of the compound is correlated with the volatility (aqueous Henry's law constant) as a result of the experimental measurements of the headspace
concentrations by the fiber extraction method.
If some characterization is available for the waste stream of concern, such as a compound identification of more than 25 percent of the major compounds present in the waste, it is recommended that selected members of these identified compounds are included in the measurements for the determination of the sitespecific SPME fiber partition factor correlation.
In some cases, after concluding the nonspeciated method runs for the waste with and without biomass, the SPME partition factor correlation may appear to be inappropriate for the waste stream. Some of the reasons for this could include incorrect compound concentration for a known compound, incorrect concentration ratios of known compounds, or test data outside the applicable range of the correlation. When there are problems with the SPME partition factor correlation, the correlation may be improved without the need to rerun the nonspeciated method runs for the waste with and without biomass.
If, unlike the petroleum compound set evaluated in reference 9, you are unable to obtain a single correlation for use in
interpreting the data that you obtain from this method, you should
consider the use of two or more correlations with multiple
correlations and multiple detectors/fiber types. A discussion of the
methods used in this multiple correlation technique alternative is
outside the scope of this discussion. This alternative of more than
one correlation should not be used without supporting experimental
investigations to verify the technical approach that you are using.
The EPA Method 25D describes the use of two different types of gas [[Page 39391]]
chromatograph detectors to more completely characterize the
compounds in the waste. You may wish to consider the use of
automatic direct headspace sampling in the case of difficulty with identifying adequate SPME correlations.
3.11 Calculation of the total nonspeciated compound concentration. The measured individual organic compound
concentrations are summed to obtain the total nonspeciated compound
concentration. Certain compounds may be excluded from this total.
Examples of components that may be excluded from the total summation procedures are the following:
3.12 Calculation of fe and fbio for each compound. The site
specific biodegradation unit characteristics are used with the measured values of the compound Henry's law value and the
biodegradation first order rate constant to estimate f
3.13 Calculation of the overall fe and fbio for the total
volatile waste components. The individual organic compound
concentrations are used with individual values of f
Reference 9 presents examples of the use of the above procedures to evaluate the fraction biodegraded for two types of biotreatment units.
3.14 Computer assisted calculations. It is possible to use
computer assisted data acquisition and data analysis in order to
reduce the extensive labor requirements to perform the above
procedures manually. You may use either manual methods, electronic
spreadsheets, or compiled programs that can directly import the gas
chromatographic computer files. Present the results for each non speciated component, the summary of the weighted average
f
4. Quality Control/Quality Assurance (QA/QC). A QA/QC plan outlining the procedures used to determine the biodegradation rate constants shall be prepared and a copy maintained at the source. The plan should include, but may not be limited to:
1. A description of the apparatus used (e.g., size, volume, method of supplying air or oxygen, mixing, and sampling procedures) including a simplified schematic drawing.
2. A description of how biomass was sampled from the activated sludge unit.
3. A description of how biomass was held prior to testing (age, etc.).
4. A description of what conditions (DO, gasliquid equilibrium, temperature, etc.) are important, what the target values are, how the factors were controlled, and how well they were controlled.
5. A description of how the experiment was conducted, including preparation of solutions, dilution procedures, sampling procedures, monitoring of conditions, etc.
6. A description of the analytical instrumentation used, how the instruments were calibrated, and a summary of the precision for that equipment.
7. A description of the analytical procedures used. If appropriate, reference to an ASTM, EPA or other procedure may be used. Otherwise, describe how the procedure is done, what is done to measure precision, accuracy, recovery, etc., as appropriate.
8. A description of how data are captured, recorded, and stored.
9. A description of the equations used and their solutions, including a reference to any software used for calculations and/or curvefitting.
3. Appendix C is amended by revising section III.E to read as follows:
E. Multiple Zone Concentration Measurements (Procedure 5)
Procedure 5 is the concentration measurement method that can be
used to determine the f
\1\ This is a mathematical division of the actual unit; not addition of physical barriers.
The estimated mass transfer coefficient for each compound in
each zone is obtained from Form II using the characteristics of each
zone. A computer model may be used. If the Water7 model or the most
recent update to this model is used, then use Form IIA to calculate
KL. The TOXCHEM or BASTE model may also be used to calculate KL for
the biological treatment unit, with the stipulations listed in
procedure 304B. Compound concentration measurements for each zone
are used in Form XIII to calculate the f
4. Appendix C is amended by revising equation C7 in section IV to read as follows:
IV. Calculation of fbio
* * * * *
[GRAPHIC] [TIFF OMITTED] TP30JN04.015
where:
M = compound specific average mass flow rate of the organic compounds in the wastewater (Mg/Yr)
n = number of organic compounds in the wastewater
* * * * *
5. Appendix C is amended by revising the references to read as follows:
1. Rajagopalan, S., R. van Compernolle, C.L. Meyer, M.L. Cano, and P.T. Sun. ``Comparison of methods for determining biodegradation kinetics of volatile organic compounds.'' Wat. Env. Res. 70: 291 298.
2. Ellis, T.G., D.S. Barbeau, B.F. Smets, C.P.L. Grady, Jr. 1996. Respirometric technique for determination of extant kinetic parameters describing biodegradation. Wat. Env. Res. 68: 917926.
3. Pitter, P. and J. Chudoba. Biodegradability of Organic Substances in the Aquatic Environment. CRC Press, Boca Raton, FL. 1990.
4. Grady, C.P.L., B. Smets, and D. Barbeau. Variability in kinetic parameter estimates: A review of possible causes and a proposed terminology. Wat. Res. 30 (3), 742748, 1996.
5. Eaton, A.D., et al. eds., Standard Methods for the Examination of Water and Wastewater, 19th Edition, American Public Health Association, Washington, DC, 1995.
6. Chudoba P., B. Capdeville, and J. Chudoba. Explanation of biological meaning of the So/Xo ratio in batch cultivation. Wat. Sci. Tech. 26 (\3/4\), 743751, 1992.
7. Technical Support Document for Evaluation of Thoroughly Mixed Biological Treatment Units. November 1998.
8. Technical Support Document for the Evaluation of Aerobic Biological Treatment Units with Multiple Mixing Zones. July 1999.
9. Saterbak, A., M.L. Cano, M.P. Williams, M.E. Huot, I.A.
Rhodes, R. van Compernolle, and C.C. Allen, 1999. Aerated draft tube
reactor test for assessing nonspeciated volatile organic compound
(VOC) biodegradation in activated sludge. Proceedings of the Water Environment
[[Page 39392]]
Federation 72nd Annual Conference and Exposition, New Orleans, LA, October 913.
[FR Doc. 0414826 Filed 62904; 8:45 am]
BILLING CODE 656050P
FOR FURTHER INFORMATION CONTACT Mary Tom Kissell, Office of Air and Radiation, Emission Standards Division (C43903), U.S. EPA, Research Triangle Park, North Carolina 27711, telephone number (919) 5414516, fax number (919) 6853219, email: kissell.mary@epa.gov.
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