[Federal Register Volume 69, Number 125 (Wednesday, June 30, 2004)]
[Proposed Rules]
[Pages 39383-39392]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-14826]
[[Page 39383]]
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 63
[OAR-2003-0191; FRL-7780-7]
RIN 2060-AE-94
Appendix C to 40 CFR Part 63--Determination of the Fraction
Biodegraded (Fbio) in a Biological Treatment Unit
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule; amendments.
-----------------------------------------------------------------------
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 site-specific
fraction of organic compounds biodegraded (Fbio) in a
biological treatment unit. The proposed amendments to Appendix C would
add a non-speciated test procedure to the batch test procedures for use
in demonstrating compliance with wastewater rules that regulate
volatile organic compounds (VOC), such as the synthetic organic
chemical manufacturing industry (SOCMI) Wastewater new source
performance standards (NSPS). The proposed amendments would also make
minor editorial changes throughout appendix C.
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.
ADDRESSES: Comments. Submit your comments, identified by Docket ID No.
OAR-2003-0191, by one of the following methods to the docket. If
possible, also send a copy of your comments to Mary Tom Kissell by
either mail or e-mail as identified in the FOR FURTHER INFORMATION
CONTACT section.
1. Federal eRulemaking Portal: http://www.regulations.gov. Follow
the on-line instructions for submitting comments.
2. Agency Web site: http://www.epa.gov/edocket. EDOCKET, EPA's
electronic public docket and comment system, is EPA's preferred method
for receiving comments. Follow the on-line instructions for submitting
comments.
3. Mail: Air Docket, Environmental Protection Agency, Mailcode:
6102T, 1200 Pennsylvania Ave., NW., Washington, DC 20460. In addition,
please mail a copy of your comments on the information collection
provisions to the Office of Information and Regulatory Affairs, Office
of Management and Budget (OMB), Attn: Desk Officer for EPA, 725 17th
St. NW., Washington, DC 20503.
4. Hand Delivery: Air Docket, Room B-102, Environmental Protection
Agency, 1301 Constitution Avenue, NW, Washington, DC 20460. Such
deliveries are only accepted during the Docket's normal hours of
operation, and special arrangements should be made for deliveries of
boxed information.
Instructions. Direct your comments to Docket ID No. OAR-2003-0191.
The EPA's policy is that all comments received will be included in the
public docket without change and may be made available online at http://www.epa.gov/edocket, including any personal information provided,
unless the comment includes information claimed to be Confidential
Business Information (CBI) or other information whose disclosure is
restricted by statute. Do not submit information that you consider to
be CBI or otherwise protected through EDOCKET, regulations.gov, or e-
mail. The EPA EDOCKET and the Federal regulations.gov Web sites are
``anonymous access'' systems, which means EPA will not know your
identity or contact information unless you provide it in the body of
your comment. If you send an e-mail comment directly to EPA without
going through EDOCKET or regulations.gov, your e-mail address will be
automatically captured and included as part of the comment that is
placed in the public docket and made available on the Internet. If you
submit an electronic comment, EPA recommends that you include your name
and other contact information in the body of your comment and with any
disk or CD-ROM you submit. If EPA cannot read your comment due to
technical difficulties and cannot contact you for clarification, EPA
may not be able to consider your comment. Electronic files should avoid
the use of special characters, any form of encryption, and be free of
any defects or viruses.
Docket. All documents in the docket are listed in the EDOCKET index
at http://www.epa.gov/edocket. Although listed in the index, some
information is not publicly available, i.e., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, is not placed on the Internet and will be
publicly available only in hard copy form. Publicly available docket
materials are available either electronically in EDOCKET or in hard
copy at the Air and Radiation Docket, EPA/DC, EPA West, Room B102, 1301
Constitution Ave., NW, Washington, DC. This docket facility is open
from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal
holidays. The Air and Radiation Docket telephone number is (202) 566-
1742. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m.,
Monday through Friday, excluding legal holidays. The telephone number
for the Public Reading Room is (202) 566-1744.
Public Hearing. If timely requests to speak at a public hearing are
received, a public hearing will be held at the EPA Office of
Administration Auditorium, Research Triangle Park, North Carolina.
Persons interested in attending the public hearing must call JoLynn
Collins to verify the time, date, and location of the hearing. The
public hearing will provide interested parties the opportunity to
present data, views, or arguments concerning these proposed amendments.
FOR FURTHER INFORMATION CONTACT: Mary Tom Kissell, Office of Air and
Radiation, Emission Standards Division (C439-03), U.S. EPA, Research
Triangle Park, North Carolina 27711, telephone number (919) 541-4516,
fax number (919) 685-3219, e-mail: [email protected].
SUPPLEMENTARY 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
Fbio in a biological treatment system. The appendix
currently contains five procedures for determining Fbio:
bench-top reactors, site-specific system performance data, inlet and
outlet concentration data, batch tests, and multiple zone concentration
measurements. Each of the procedures in appendix C are compound-
specific (i.e., the individual compound fraction biodegraded
(Fbio) is determined for each identified compound and then
summed to obtain an overall Fbio). However, in developing
the new source performance standards for wastewater sources in the
synthetic organic chemical manufacturing industry, we realized that
Fbio determinations on an individual compound basis may be
problematic for sources demonstrating compliance for large numbers of
undefined VOC.
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 cost-effective
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 Fbio that does not require
identification of specific OWWC.
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 Fbio for the biological
treatment system is calculated from the sum of the individual organic
compound concentrations and individual Fbio values. Appendix
C to 40 CFR part 63 allows the use of manual or computer-assisted
methods to analyze the GC concentration data.
Today's proposed non-speciated aerated draft tube reactor test
method is an appropriate addition to appendix C to 40 CFR part 63 to
provide a more cost-effective option for compliance demonstrations for
activated sludge biological treatment units affected by wastewater
rules regulating VOC. While we consider this to be a cost-effective
option, the non-speciated 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
non-speciated 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 Fbio
reflects the actual destruction of the HAP and not the average of all
the organic compounds present in the wastewater. Therefore, today's
proposed non-speciated aerated draft tube reactor test method may only
be used to comply with rules that regulate VOC, such as the SOCMI
Wastewater NSPS.
In addition to the non-speciated 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 less-costly 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 not-for-profit 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 104-4, 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 cost-effective, 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 cost-effective, 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 5-501 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 104-113; 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. OAR-2003-0191 and A-94-32.
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 Fbio introductory text to read as follows:
Appendix C to Part 63--Determination of the Fraction Biodegraded
(Fbio) in a Biological Treatment Unit
* * * * *
III. Procedures for Determination of Fbio
* * * * *
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 non-speciated aerated draft tube reactor
test. The non-speciated 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 1-4. A detailed discussion of the non-speciated 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
(So) to biomass (Xo) ratio (see references 3,
4, and 6). This ratio is typically measured in chemical oxygen
demand (COD) units. When the So/Xo ratio is
low, cell multiplication and growth in the batch test is negligible
and the kinetics measured by the test are representative of the
kinetics in the activated sludge unit of interest. The
So/Xo ratio for a batch test is determined
with the following equation:
[GRAPHIC] [TIFF OMITTED] TP30JN04.016
Where:
So/Xo = initial substrate to biomass ratio on
a COD basis
Si = initial substrate concentration in COD units(g COD/
liter)
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
So/Xo ratio (on a COD basis) must be initially
less than 0.5.
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 DO-limited. 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/Co)=(GKeq/V)t (Eqn. App. C-2)
Where:
C = concentration at time, t (min)
Co = concentration at t = 0
G = volumetric gas flow rate (ml/min)
V = liquid volume in the batch reactor (ml)
Keq = Henry's law constant (mg/L-gas)/(mg/L-liquid)
t = time (min)
A plot of -ln(C/Co) as a function of t will have a
slope equal to GKeq/V. The equilibrium assumption can be
verified by comparing the experimentally determined Keq
for the system to literature values of the Henry's Law constant
(including those listed in this appendix). If Keq does
not match the Henry's law constant, Keq shall be
determined from analysis of the headspace and liquid concentration
in a batch system.
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
Keq = Henry's Law constant measured in the system, (mg/
liter gas)/(mg/liter liquid)
V = volume of liquid in the reactor, liters
X = biomass concentration (g MLVSS/liter)
Qm = maximum rate of substrate removal, mg/g MLVSS/hr
Ks = Monod biorate constant at half the maximum rate, mg/
liter
Equation App. C-3 can be integrated to obtain the following
equation:
[GRAPHIC] [TIFF OMITTED] TP30JN04.008
where:
A = GKeqKs + QmVX
B = GKeq
So = test compound concentration at t=0
This equation is used along with the substrate concentration
versus time data to determine the best fit parameters (Qm
and Ks) to describe the biodegradation process in the
aerated reactor. If the Aerated Reactor test is used, the following
procedure is used to analyze the data. Evaluate Keq for
the compound of interest with Form XI. The concentration in the
vented headspace or liquid is measured as a function of time and the
data is entered on Form XI. A plot is made from the data and
attached to the Form XI. Keq is calculated on Form XI and
the results are contrasted with the expected value of Henry's law
obtained from Form IX. If the comparison is satisfactory, the
stripping constant is calculated from Keq, completing
Form XI. The values of Keq may differ because the
theoretical value of Keq may not be applicable to the
system of interest. If the comparison of the calculated
Keq from the form and the expected value of Henry's law
is unsatisfactory, Form X can alternatively be used to validate
Keq. If the aerated reactor is demonstrated to not be at
equilibrium, either modify the reactor design and/or operation, or
use another type of batch test. This equilibrium testing must only
be demonstrated for one or more of the most volatile compounds to be
tested for biodegradation. Once it is demonstrated that the aerated
reactor achieves equilibrium, then Form IX is used to adjust
published or measured Henry's law constants for the other volatile
compounds to be tested.
The compound-specific 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 Keq determined on Form
XI and entered on Form XII.
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 curve-fitting 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 first-order 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,
fbio. The number transferred to Form III is obtained from
Form XII, line 9.
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 DO-limited. 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, Keq may be determined by simultaneously measuring
gas and liquid phase concentrations at different times within a
given experiment. The equilibrium testing must only be demonstrated
for one or more of the most volatile component(s) that will be
tested. A constant ratio of gas/liquid concentrations indicates that
equilibrium conditions are present and Keq is not a
function of concentration. This ratio is then taken as the
Keq for the specific component(s) in the test. It is not
necessary to measure Keq for each experiment. If the
ratio is not constant, the equilibrium assumption is not valid and
it is necessary to (1) increase mixing energy for the system and
retest for the equilibrium assumption, or (2) use a different type
of test that does not depend on headspace characterization (for
example, a collapsible volume reactor).
The concentration of a compound decreases in the bioreactor due
to biodegradation according to Equation App. C-5:
[GRAPHIC] [TIFF OMITTED] TP30JN04.009
where:
s = test compound concentration (mg/liters)
Vl = the average liquid volume in the reactor (liters)
Vg = the average gas volume in the reactor (liters)
Qm = maximum rate of substrate removal (mg/g MLVSS/hr)
Keq = Henry's Law constant determined for the test, (mg/
liter gas)/(mg/liter liquid)
Ks = Monod biorate constant at one-half the maximum rate
(mg/liter)
t = time (hours)
X = biomass concentration (g MLVSS/liter)
So = test compound concentration at time t=0
Equation App. C-5 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 (Qm
and Ks) to describe the biodegradation process in the
sealed reactor.
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
Keq. The ratio of headspace to liquid concentrations must
be constant in order to confirm that equilibrium conditions exist.
If equilibrium conditions are not present, additional mixing or an
alternate reactor configuration may be required.
The compound-specific 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 Keq from Form X and entered on Form XII.
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 curve-fitting procedure must be based upon Equation App. C-6.
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 first-order 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,
fbio. The number transferred to Form III is obtained from
Form XII, line 9.
The number on Form XII line 9 will equal the Monod first-order
biorate constant if the full-scale system is operated in the first-
order range. If the full-scale system is operated at concentrations
above that of the Monod first-order range, the value of the number
on line 9 will be somewhat lower than the Monod first-order 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. C-6 is valid only if Vl and Vg
do not change more than 10 percent (i.e., they can be approximated
as constant for the duration of the test). Since biodegradation is
occurring only in the liquid, as the liquid concentration decreases
it is necessary for mass to transfer from the gas to the liquid
phase. This may require vigorous mixing and/or reducing the volume
in the headspace of the reactor.
If there is no headspace (e.g., a collapsible reactor), Equation
App. C-6 is independent of Vl and there are no
restrictions on the liquid volume. If a membrane or bag is used as
the collapsible-volume 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. Non-speciated 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
Fbio for non-speciated VOC. The methods and procedures
that are used with the Aerated reactor test (described in section 1
above) are also used
[[Page 39389]]
with the non-speciated 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 non-speciated 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 non-speciated 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 non-speciated organic
compound. One run of the non-speciated 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 Non-speciated organic compound concentration. One run of
the non-speciated 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 non-speciated organic compounds.
One run of the non-speciated 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 non-speciated organic
compound. Two runs of the non-speciated 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 fe and fbio for
each non-speciated organic compound. The use of Form III or an
equivalent method is used to evaluate the fraction biodegraded
(individual Fbio) using the Henry's law value for each
component (3.6), the amount of each component (3.9), and the
biodegradation rate for each component (3.7), together with the
characteristics of the biotreatment unit. See section 3.12.
3.1.6 Overall Fe and Fbio for the total
concentration of non-speciated organic compounds. The use of Form
III or an equivalent method is used to evaluate the fraction
biodegraded (individual fbio) using the Henry's law value
for each component (3.6), the amount of each component (3.9), and
the biodegradation rate for each component (3.7), together with the
characteristics of the biotreatment unit.
These individual Fbio numbers for each of the
components are used to obtain an overall Fbio value for
the overall non-speciated waste. Non-speciated compounds with low
Henry's law constants of less than 0.1 mol fraction gas per mol
fraction in liquid at one atmosphere can be excluded from this
summation.
A weighted summation of these individual estimates of biological
and air emission removal is used to obtain an overall
Fbio and an overall Fe. See section 3.13.
3.2 Reactor configuration. An aerated draft tube reactor is used
for the biokinetics testing for the non-speciated 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 non-speciated 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 non-speciated aerated draft tube
reactor test as discussed in section D.1, using Equation C-2.
A plot of -ln(C/Co) as a function of t will have a
slope equal to GKeq/V. Verification of equilibrium can be
performed initially and periodically with a set of known volatile
compounds with known Henry's law constants. The selection of
compounds should represent the most volatile compounds in the waste
stream (at least as great as the experimentally measured Henry's law
constants for the top 5 percent of the non-speciated components, or
alternatively with Henry's law constants of 300 y/x). Experimentally
measured Henry's law values are available from the WATER7 (or any
subsequent update to the model) data base for a number of compounds.
In addition, the compounds that are selected for the verification of
equilibrium should be included in the determination of the SPME
fiber partition factor. Verification of equilibrium in the non-
speciated aerated draft tube reactor test under each set of
operating conditions is important because accurate measurement of
the Henry's law constant is necessary to permit accurate
characterization of non-speciated peaks. Non-speciated 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
non-speciated compounds in this test that closely represent the
conditions in the full-scale biodegradation unit that you are
evaluating. Since the components and concentrations are generally
unknown for this non-speciated method, samples of actual wastewater
should be obtained from the applicable location in the full-scale
facility, or as close to these conditions as practicable, such as a
sample of wastewater from a pilot plant, a full-scale 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
Keq = Henry's Law constant measured in the system, (mg/
liter gas)/(mg/liter liquid)
V = volume of liquid in the reactor, liters
X = biomass concentration (g MLVSS/liter)
K1 = first order biodegradation rate constant, liter/g
MLVSS/hr
Equation App. C-7 can be integrated to obtain the following
equation:
[[Page 39390]]
[GRAPHIC] [TIFF OMITTED] TP30JN04.012
where:
Peakareat = the area of the non-speciated compound peak
at time t,
Peakareao = the area of the non-speciated compound peak
at the beginning of the run,
GKeq/V = contribution to the slope from stripping only,
and
K1X = contribution to the slope from biodegradation.
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. C-8 and the intercept of this line on the y axis
equals ln (Peakareao).
A discussion of Equation App. C-8 is provided in reference 9.
This equation is used to analyze the two stripping runs, with and
without biodegradation. Evaluate the slope for each non-speciated
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
-GKeq. The value of Keq is then equal to the
product of the negative of the slope and V, divided by G.
3.7 Biodegradation rate constant. To evaluate the first order
biorate constant, use the slope for each non-speciated peak for the
run without biodegradation and subtract the corresponding slope of
the non-speciated peak with biodegradation. This difference equals
K1X. The value of K1 that is determined in
this manner is used to characterize the biodegradation rate under
the conditions in the full-scale biodegradation unit that you are
evaluating.
3.8 Accuracy concerns. The non-speciated 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 non-speciated
compound, the value of K1 is set to zero. A negative
value of K1 is never used. If the specific compound of
concern has a statistically significant negative value of
K1, this can be an indication of the formation of the
compound as a byproduct and is reported as an anomalous result. It
is necessary to provide documentation of data and calculations.
If the stripping rate constant is relatively large when compared
to the biorate, it may be difficult to obtain an accurate evaluation
of the first-order 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 non-speciated organic compound is calculated by measuring
the initial area of the chromatographic peak of the individual
compound, Peakareao, the ratio of the peak area to the
gas phase concentration, F, the SPME fiber partition factor,
Kfiber, and the partition coefficient, Keq.
The Peakareao is the intercept of the line with the y
axis (plot of ln Peakarea vs. time). If automatic gas sampling is
used for the analysis, a representative calibration of the gas
chromatographic peak area and the gas phase concentration is
required, and a correlation for the fiber partition factor is not
used because the SPME method is not used. For complex chemicals with
relatively poor biodegradation rates, it may be necessary to modify
the procedure using multiple columns or detectors.
The equation used for the SPME method is as follows:
[GRAPHIC] [TIFF OMITTED] TP30JN04.013
where:
CL = the concentration of the component in the water,
(mg/L),
PA = the integrated peak area of the component in the gas
chromatograph, (area counts),
Keq = the ratio of the concentration of the component in
the headspace to the concentration of the component in the water,
(mg/L per mg/L),
Kfiber = the ratio of the mass on the extraction fiber to
the concentration of the component in the headspace, (mg per mg/L),
and
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 Kfiber is the
ratio of the mass of compound to the concentration in the headspace
at equilibrium with the aqueous solution. A correlation is then
obtained between the value of Kfiber and the retention
time of the detector response.
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 site-specific SPME fiber
partition factor correlation.
In some cases, after concluding the non-speciated 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 non-speciated 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 non-speciated compound
concentration. The measured individual organic compound
concentrations are summed to obtain the total non-speciated 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:
Components that are present in the vapor phase in
concentrations too low to measure.
Components that are identified and have specific
regulatory exclusion.
Components that have gas chromatographic retention
times that are substantially greater than can be considered
characteristic of volatile components.
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 fe
and fbio for each compound.
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 fe and
fbio to obtain the total biological removal and the total
air emission removal from the treatment unit. In the case of an
ideal stirred tank reactor, the amount of each component entering
the reactor is calculated by multiplying the flow rate of the waste
(m3/s) by the concentration (g/m3) to obtain
the individual loading rate (g/s). For each compound that is not
excluded, the individual loading is summed to obtain the total
loading. The overall biological removal is the sum of the products
of the individual loading rate (g/s) and the individual value of
fbio. The overall air removal is the sum of the products
of the individual loading rates (g/s) and the individual values of
fe. The overall fbio value is the ratio of the
overall biological removal to the total loading. The overall
fe value is the ratio of the overall air emissions loss
to the total loading.
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
fbio using each relevant component, and supporting
quality assurance information. The slope and intercept of the
correlation curve, the correlation coefficient, and the number of
data points used for the correlation are examples of supporting
quality assurance information.
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, gas-liquid 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
curve-fitting.
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 fbio for units that are not
thoroughly mixed and thus have multiple zones of mixing. As with the
other procedures, proper determination of fbio must be
made on a system as it would exist under the rule. For purposes of
this calculation, the biological unit must be divided \1\ into zones
with uniform characteristics within each zone. The number of zones
that is used depends on the complexity of the unit. Reference 8, ``A
Technical Support Document for the Evaluation of Aerobic Biological
Treatment Units with Multiple Mixing Zones,'' is a source for
further information concerning how to determine the number of zones
that should be used for evaluating your unit. The following
information on the biological unit must be available to use this
procedure: (1) Basic unit variables such as inlet and recycle
wastewater flow rates, type of agitation, and operating conditions;
(2) measured representative organic compound concentrations in each
zone and the inlet and outlet; and (3) estimated mass transfer
coefficients for each zone.
---------------------------------------------------------------------------
\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 II-A 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 fbio. A copy of
Form XIII is completed for each of the compounds of concern treated
in the biological unit.
4. Appendix C is amended by revising equation C-7 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: 917-926.
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), 742-748, 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\), 743-751, 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 non-speciated 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 9-13.
[FR Doc. 04-14826 Filed 6-29-04; 8:45 am]
BILLING CODE 6560-50-P