[Comment: For dates of non-regulatory government
publications, publications of recognized organizations and associations,
federal rules and federal statutory provisions referenced in this rule, see
rule 3745-2-02 of the Administrative Code.]
(A) For each discharge that may require
the development of water quality-based effluent limitations (WQBELs), Ohio EPA
shall develop wasteload allocations (WLAs) for pollutants if any of the
following apply:
(1) The maximum projected
effluent quality (PEQ) determined for that discharge and pollutant is greater
than or equal to twenty-five per cent of the smallest of the applicable maximum
criteria, where the maximum PEQ is determined in accordance with paragraph (D)
of this rule and the criteria are determined in accordance with paragraph (E)
of this rule.
(2) The average PEQ
determined for that discharge and pollutant is greater than or equal to
twenty-five per cent of the smallest of the applicable average criteria, where
the average PEQ is determined in accordance with paragraph (D) of this rule and
the criteria are determined in accordance with paragraph (E) of this
rule.
(3) The discharge is
considered by Ohio EPA to be interactive with one or more other discharges to
the receiving water for this pollutant and one or more of the discharges will
require WLAs for this pollutant based on conditions other than this
condition.
(4) The pollutant has the
potential to threaten or impair the designated used of the receiving waters and
is known or expected to occur in the discharge during the applicable permit
period.
(5) A WQBEL is required
to meet other federal, state, or local regulations or as may be necessary to
implement surface water or NPDES permit programs.
(B) The following exceptions apply to
paragraph (A) of this rule:
(1) If all available
effluent data for a pollutant are below the analytical detection levels applied
to that data, then a maximum PEQ and an average PEQ cannot be calculated for
that pollutant and a determination of WLAs will not be required unless one or
more of the conditions in paragraphs (A)(3) to (A)(5) of this rule
apply.
(2) If Ohio EPA
determines that a WLA is required for a pollutant based on any one of the
conditions listed in paragraph (A) of this rule, Ohio EPA is not required to
evaluate the applicability of the other conditions.
(3) For pollutants that
include both dissolved and total recoverable numeric aquatic life criteria in
Chapter 3745-1 of the Administrative Code, Ohio EPA may use the total
recoverable criteria alone to determine the applicability of conditions in
paragraphs (A)(1) and (A)(2) of this rule.
(C) For discharges in the lake Erie
basin: For pollutants that require WLA determination based on paragraph (A)(4)
or (A)(5) of this rule, but do not have established numeric criteria in Chapter
3745-1 of the Administrative Code, Ohio EPA shall evaluate available data to
determine applicable numeric criteria. Ohio EPA shall also take the following
actions:
(1) If available data are
insufficient to determine numeric criteria and the pollutant is included in
table 6 of the "Final Water Quality Guidance for the Great Lakes
System" (40 C.F.R. 132), Ohio EPA shall use all available and relevant
information to estimate ambient screening values that will protect humans from
health effects other than cancer, and aquatic life from acute and chronic
effects.
(2) If the maximum PEQ is
greater than or equal to twenty-five per cent of the ambient screening value
for protection of aquatic life from acute effects, or the average PEQ is
greater than or equal to twenty-five per cent of the lowest of the ambient
screening values for protection of human health or aquatic life from chronic
effects, Ohio EPA shall develop WLAs based upon the ambient screening values
that are consistent with rule 3745-2-05 of the Administrative
Code.
(3) In accordance with
paragraph (B)(6) of rule 3745-2-06 of the Administrative Code, Ohio EPA shall
use the WLAs based on ambient screening values to determine if data must be
generated to develop numeric criteria for that pollutant.
(4) Ohio EPA shall not
use the WLAs based on ambient screening values to develop WQBELs.
(D) For each pollutant for which
discharge-specific effluent data is available and one or more data values equal
or exceed the analytical detection levels applied to that data, Ohio EPA shall
determine the maximum PEQ and the average PEQ to meet the following
requirements, unless otherwise exempt from determination by paragraph (B) of
this rule.
(1) The
discharge-specific effluent monitoring data shall be selected to best represent
the magnitude and variability of that pollutant in the discharge as projected
for the applicable period of the permit.
(a) The most recent five years of data shall be used unless an
alternate period of record better represents the projected effluent quality.
Such alternative periods of record may include, but are not limited to, shorter
time periods that reflect changes in discharge characteristics that result from
changes in manufacturing processes or wastewater treatment systems or their
operation.
(b) Extreme outliers and other data anomalies that result from
collection, analysis, or recording errors or non-repeatable plant operation or
discharge conditions may be eliminated from the data.
(c) The data shall be based on independent grab or twenty-four
hour composite effluent samples. If such data are unavailable, other
discharge-specific effluent data may be used if the discharger demonstrates
that the data properly represent the long-term daily variability of the
pollutant in the effluent, or Ohio EPA can adjust the data by a scientifically
defensible procedure to represent independent daily values.
(d) If available data do not adequately represent the projected
magnitude and variability of the pollutant, Ohio EPA may adjust the available
data or the PEQ calculation procedures to approximate the projected changes in
effluent quality provided these adjustments are scientifically
defensible.
(2) The maximum PEQ shall
be determined as the ninety-fifth percentile of the projected population of
daily values of the discharge-specific effluent monitoring data using a
scientifically defensible statistical method that accounts for and captures the
long-term daily variability of the effluent quality, accounts for limitations
associated with sparse data sets, and assumes a log-normal distribution of the
discharge-specific effluent data (unless another distribution can be
demonstrated to be more appropriate).
(3) The average PEQ shall
be determined as the ninety-fifth percentile of the projected population of
monthly averages of the discharge-specific effluent monitoring data using a
scientifically defensible statistical method that accounts for and captures the
long-term variability of the monthly average effluent quality, accounts for
limitations associated with sparse data sets, and assumes a log-normal
distribution of the discharge-specific effluent data (unless another
distribution can be demonstrated to be more appropriate).
(4) For pollutants with
numeric criteria representing the sum of two or more isomers or metabolites
(such as but not limited to halomethanes, polyaromatic hydrocarbons, and DDT),
the PEQ may be estimated as the sum of the PEQs determined for the individual
isomers or metabolites.
(5) In the absence of
reliable effluent data for a new or expanded discharge, the requested discharge
level will be used as the PEQ for use in reasonable potential
determinations.
(E) The numeric water quality criteria
applicable to the receiving waters are determined in Chapter 3745-1 of the
Administrative Code.
(1) For numeric criteria
that vary with water hardness, Ohio EPA shall calculate the applicable numeric
criteria based on a water hardness concentration that meets the
following:
(a) If water hardness data are available that represent the
concentration in the receiving water downstream of the mixing zone under the
applicable design conditions, as follows:
(i) The median of the
water hardness values shall be used if ten or more values are
available.
(ii) The arithmetic mean
of the water hardness values shall be used if less than ten values are
available.
(b) If water hardness data are not available that represent the
concentration in the receiving water downstream of the mixing zone under the
applicable design conditions, the annual twenty-fifth percentile of water
hardness data considered by Ohio EPA to be representative of the natural
background conditions for that receiving water shall be used.
(c) If discharge-specific data are available that adequately
represent the projected water hardness of the effluent over the applicable
permit period, a water hardness concentration based on the effluent data and
determined in accordance with paragraph (E)(1)(a) of this rule may be used to
determine the inside mixing zone maximum (IMZM) numeric criterion applicable to
that discharge provided that an area of initial mixing (AIM) is not applied to
this discharge.
(d) If an AIM is applied to the discharge, a concentration
representing the water hardness at the edge of the AIM may be used to determine
IMZM numeric criteria applicable to that discharge if the discharge meets all
of the following conditions:
(i) The concentration is
based on receiving water and discharge water hardness data that meet the
conditions specified in paragraphs (E)(1)(a) and (E)(1)(c) of this rule,
respectively.
(ii) The concentration is
calculated based on the dilution applicable at the edge of the
AIM.
(iii) Other factors that
may affect water hardness are accounted for, such as, but not limited to,
effluent and receiving water variability and chemical
interactions.
(2) For numeric criteria
that vary with pH (other than for ammonia), Ohio EPA shall calculate the
applicable numeric criteria based on a pH that meets the
following:
(a) If pH data are available that represent the long term daily
variation in the receiving water downstream of the mixing zone under the
applicable design conditions, the median of the pH values shall be
used.
(b) If pH data are not available that represent the long term
daily variation in the receiving water downstream of the mixing zone under the
applicable design conditions, the annual twenty-fifth percentile or
seventy-fifth percentile (whichever value results in the more stringent numeric
criterion) of pH data considered by Ohio EPA to be representative of the
natural background conditions for that receiving water shall be
used.
(c) If discharge-specific data is available that adequately
represents the projected pH of the effluent over the applicable permit period,
the median pH based on the effluent data may be used to determine the IMZM
numeric criterion applicable to that discharge provided that an AIM is not
applied to this discharge.
(d) If an AIM is applied to the discharge, a value representing
the pH in the receiving water at the edge of the AIM may be used to determine
IMZM numeric criteria applicable to that discharge if it meets the following
conditions:
(i) The pH is based on
receiving water and discharge water pH data that meet the conditions specified
in paragraphs (E)(2)(a) and (E)(2)(c) of this rule, respectively.
(ii) The pH is calculated
based on the dilution applicable at the edge of the AIM.
(iii) Other factors that
may affect pH are accounted for, such as, but not limited to, effluent and
receiving water variability and chemical interactions.
(3) For ammonia, unless
alternative periods are found to be necessary or appropriate in order to
maintain water quality criteria, Ohio EPA shall determine numeric criteria for
two seasonal periods, summer and winter. Ohio EPA shall calculate numeric
criteria for ammonia based on temperature and pH values that meet the
following:
(a) Temperature and pH shall be based on data collected during
the following periods:
(i) June through
September for the summer season.
(ii) December through
February for the winter season.
(iii) The period of data
that best represents the season for alternative seasonal periods.
(b) For each applicable season, temperature and pH statistics
shall be determined based on the available ambient data that best represents
the long-term daily variation in the receiving water downstream of the mixing
zone. The following statistics shall be used to determine the applicable
ammonia criteria:
(i) Seventy-fifth
percentile for temperature.
(ii) Seventy-fifth
percentile for pH.
(c) If data are not available for the receiving water, data from
another water body may be used if it can be demonstrated that the other water
body has similar temperature and pH related characteristics. If data are not
available for a similar water body, data considered by Ohio EPA to be
representative of the natural background conditions for that receiving water
may be used.
(4) Other methods for
determining the applicable water hardness, pH, and temperature may be allowed
by Ohio EPA provided the methods are scientifically defensible and can be
demonstrated to maintain all applicable water quality criteria.
(5) For WLA
determinations based on probabilistic analysis, as allowed by rule 3745-2-05 of
the Administrative Code, Ohio EPA shall consider the numeric water quality
criteria applicable to the receiving water to be maintained if the allowable
duration and frequency of exceedance recommended in the U.S. EPA
"Technical Support Document for Water Quality-based Toxics Control"
are met. Ohio EPA may allow an alternative duration and frequency of exceedance
if the duration and frequency are scientifically defensible and can be
demonstrated to provide sufficient protection of the designated water quality
uses of the receiving water.
(F) For metals that have both dissolved
and total recoverable aquatic life criteria in Chapter 3745-1 of the
Administrative Code and for which paragraph (A) of this rule applies, Ohio EPA
shall determine the appropriate criteria applicable to determining WLAs using
the following conditions:
(1) Except for hexavalent
chromium, Ohio EPA shall convert the dissolved aquatic life criteria to
effective total recoverable criteria by multiplying the applicable dissolved
criteria by the dissolved metal translator (DMT) applicable to that metal,
receiving water, and discharge, as defined in paragraphs (F)(4) to (F)(8) of
this rule.
(2) In the absence of an
applicable DMT, Ohio EPA shall apply the total recoverable aquatic life
criteria to determine WLAs for that metal as provided in Chapter 3745-1 of the
Administrative Code and determined in accordance with paragraph (E) of this
rule.
(3) For hexavalent
chromium, Ohio EPA shall apply the dissolved aquatic life criteria to develop
and express WLAs in dissolved form.
(4) For acute and chronic
aquatic life criteria, an applicable DMT shall represent the receiving waters
downstream of the chronic mixing zone under design conditions.
(5) For the IMZM
criterion, the DMT applicable to the acute aquatic life criterion shall be
applied, with the following exceptions:
(a) When the effluent is known or suspected to have a DMT
significantly lower than that applied to the acute aquatic life criterion,
either of the following apply:
(i) An effluent DMT may
be determined and applied if it meets the protocol provided in paragraph (G) of
this rule.
(ii) If an applicable
effluent DMT is not determined, the total recoverable IMZM criteria shall be
applied in accordance with paragraph (F)(2) of this rule.
(b) When the effluent is known to have a DMT higher than that
applied to the acute aquatic life criterion, an alternative DMT of up to the
effluent DMT may be applied if the discharger can demonstrate that it maintains
all applicable dissolved aquatic life criteria in the receiving water and the
effluent DMT is determined in accordance with paragraph (G) of this
rule.
(6) A discharge-specific
DMT for a metal may be determined by the discharger or Ohio EPA in accordance
with paragraph (G) of this rule. The discharge-specific DMT shall be applied by
Ohio EPA to determine the effective total recoverable criteria applicable to
that metal.
(7) Ohio EPA may
determine a DMT for a specific water body segment. If a
water-body-segment-specific DMT is available and applicable to the discharge
and receiving water and an acceptable discharge-specific DMT is not available,
Ohio EPA shall apply that water-body-segment-specific DMT to determine the
effective total recoverable criteria applicable to that metal.
(8) Ohio EPA may
determine a DMT applicable to water bodies in a specific region of the state of
Ohio. If a region-specific DMT is available and applicable to the discharge and
receiving water and an acceptable discharge-specific or
water-body-segment-specific DMT is not available, Ohio EPA shall apply the
region-specific DMT in determining effective total recoverable criteria
applicable to that metal.
(G) A discharge-specific DMT shall be
determined in accordance with the U.S. EPA document, "The Metals
Translator: Guidance For Calculating A Total Recoverable Permit Limit From A
Dissolved Criterion" (translator document) except as follows:
(1) Only those procedures
in the translator document which are intended for determination of
site-specific translators and are based on direct measurement of dissolved and
total recoverable metal concentrations may be applied in the determination of
discharge-specific DMTs.
(2) The
discharge-specific DMT shall be determined to represent the receiving water
downstream of the applicable mixing zone under the more restrictive of the
following conditions:
(a) The stream design flow and other receiving water and effluent
conditions applicable to the determination of WLAs for aquatic life criteria
pursuant to rule 3745-2-05 of the Administrative Code and paragraph (E) of this
rule.
(b) Other receiving water or effluent conditions that are
determined by Ohio EPA to be more critical in regard to the impact of dissolved
metals on aquatic life.
(3) The
discharge-specific DMT shall represent the ratio of the total recoverable
concentration of a metal to the dissolved concentration. An individual DMT
measurement shall be determined as the ratio of the total recoverable
concentration of a metal in a water sample to the dissolved concentration of
that metal in the same water sample or a separate sample collected at the same
time and location.
(4) Clean sampling and
analytical procedures in accordance with the U.S. EPA document "Method
1669: Sampling Ambient Water for Trace Metals at EPA Water Quality Criteria
Levels" shall be applied in the collection and analysis of the metals
concentrations used to determine a DMT measurement. Alternative sampling and
analytical procedures may be applied if the procedures can be shown to provide
sufficient protection from contamination, such that any contamination of the
samples that may occur will not be significant relative to the DMT
measurement.
(5) At a minimum, the
following measurements shall also be made at the same time and location as each
of the DMT measurements:
(a) Total suspended solids concentration.
(b) Water hardness.
(c) Water pH.
(d) Water temperature.
(e) Receiving water flow and effluent flow.
(6) If either or both of
the total recoverable and dissolved concentrations on which a DMT measurement
is based are less than the applicable practical quantification level (PQL),
then the DMT measurement shall not be used in determining the
discharge-specific DMT unless the inaccuracies associated with concentrations
less than PQL can be demonstrated to be insignificant or are accounted for
through application of scientifically defensible conservative measures.
Additionally, if either or both of the total recoverable and dissolved
concentrations on which a DMT measurement is based are less than the applicable
analytical detection level, the following requirements apply:
(a) If the total recoverable concentration, or both the total
recoverable and dissolved concentrations, are below the applicable detection
level, then the DMT measurement shall not be used in determining the
discharge-specific DMT.
(b) If only the dissolved concentration is below the applicable
detection level, then the DMT measurement may be used in determining the
discharge-specific DMT if the dissolved concentration is assumed to equal a
concentration no less than the applicable analytical detection
level.
(7) All DMT measurements
applicable to the discharge and receiving water shall be used in determining
the discharge-specific DMT, unless the DMT measurements are eliminated in
accordance with paragraph (G)(6) of this rule or the DMT measurements can be
demonstrated to be inaccurate or unrepresentative of the conditions applicable
under paragraph (G)(2) of this rule. A DMT measurement less than one, where the
observed dissolved metal concentration exceeds the total recoverable
concentration, shall not be eliminated unless the individual concentration
measurements can otherwise be demonstrated to be inaccurate.
(8) If the DMT
measurements were collected during receiving water and effluent conditions
approximating the conditions applicable under paragraph (G)(2) of this rule,
the following requirements apply to the determination of a discharge-specific
DMT.
(a) The discharge-specific DMT shall be calculated as the
geometric mean of the measured translators if all of the following conditions
are met:
(i) At least ten DMT
measurements are available and used in that calculation.
(ii) All DMT measurements
used in the calculation adequately represent the conditions applicable under
paragraph (G)(2) of this rule.
(iii) The observed
variation of the DMT measurements about the geometric mean will not result in
significant exceedances of the applicable aquatic life criteria if the
geometric mean is applied as the discharge-specific DMT.
(b) If the conditions in paragraph (G)(8)(a) of this rule are not
met, but sufficient data are available to accurately estimate the variability
of DMT measurements, the discharge-specific DMT shall be calculated by a
scientifically defensible method that accounts for the inaccuracies associated
with small data sets or data that may not represent the conditions applicable
under paragraph (G)(2) of this rule. Such methods may include, but are not
limited to, selection of a statistic that produces a DMT sufficiently lower
than the geometric mean in order to provide reasonable assurance that possible
inaccuracies in the discharge-specific DMT will not result in exceedance of
applicable aquatic life criteria.
(9) If DMT measurements
were collected over a range of receiving water and effluent conditions,
including conditions outside those applicable under paragraph (G)(2) of this
rule, a scientifically defensible method shall be applied to determine the
mathematical relationships between the DMT measurements and the other measured
factors, separately and in combination, including but not limited to stream
flow and total suspended solids concentrations. Scientifically defensible
methods shall also be used to determine the values for each measured factor
that will occur during the receiving water and effluent conditions applicable
under paragraph (G)(2) of this rule. The discharge-specific DMT shall be
determined based on the most significant of these relationships and values to
represent the conditions applicable under paragraph (G)(2) of this rule. These
methods shall account for any inaccuracies or uncertainties associated with the
data or the derived relationships so as to provide reasonable assurance that
possible inaccuracies in the discharge-specific DMT will not result in
exceedance of applicable aquatic life criteria.
(10) Before conducting a
discharge-specific DMT study, the discharger may complete a plan of study in
accordance with Chapter 5 of the translator document, as referenced in
paragraph (G) of this rule, and submit the study to Ohio EPA for review and
comment.
(11) After completion of
the discharge-specific DMT study, the discharger shall submit a final report to
Ohio EPA, including at a minimum the following information:
(a) A description of the field activities and, as applicable, any
variations from the plan of study.
(b) All data collected during the study.
(c) A discharge-specific DMT for each metal evaluated, calculated
based on the study and in accordance with paragraph (G) of this
rule.
(d) Descriptions and justifications for all analyses,
calculations, and assumptions made in the determination of the
discharge-specific DMT.
(12) Each
discharge-specific DMT calculated pursuant to the requirements of paragraph (G)
of this rule shall be used in determination of WLAs for that discharge in
accordance with paragraph (F) of this rule. If a discharge-specific DMT for a
metal was not calculated in accordance with the requirements of paragraph (G)
of this rule, Ohio EPA shall not apply that DMT in determination of WLAs, but
may take one of the following actions:
(a) Based on the discharge-specific DMT study and other available
information, Ohio EPA may determine and apply a discharge-specific DMT for that
metal, in accordance with this rule.
(b) Ohio EPA may allow the discharger to revise the study and
discharge-specific DMT for that metal to meet the requirements of this rule and
resubmit the final report.
(13) All studies and
reports required under paragraph (G) of this rule shall be in compliance with a
schedule agreed upon between Ohio EPA and the discharger such that the
discharge-based DMTs will be completed prior to the scheduled determination of
WLAs for that discharge.
(14) If sampling is
required as a condition of an NPDES permit to verify the continued validity of
an applied discharge-specific DMT for a metal (in accordance with paragraph (C)
of rule 3745-33-05 of the Administrative Code), the following requirements
shall apply:
(a) At least one DMT measurement shall be made during the permit
period that, in Ohio EPA's determination, adequately represents the
receiving water downstream of the mixing zone for the discharge under the
applicable design conditions and meets the requirements of paragraph (G) of
this rule.
(b) The DMT measurements shall be collected in accordance with a
schedule in the NPDES permit such that the results of the measurement will be
available prior to the next scheduled determination of WLAs for that
discharge.
(15) If Ohio EPA
determines, based on DMT measurements collected in accordance with paragraph
(G)(14) of this rule, that a discharge-specific DMT is still valid, Ohio EPA
may apply that discharge-specific DMT in determination of WLAs required for
NPDES permit renewal for that discharge.
(16) If Ohio EPA
determines, based on DMT measurements collected in accordance with paragraph
(G)(14) of this rule, that the applied discharge-specific DMT may no longer be
valid for that discharge, Ohio EPA may take one of the following
actions:
(a) Ohio EPA may require the discharger to collect additional DMT
measurements and redetermine an applicable discharge-specific DMT, in
accordance with this rule. Data from the original discharge-specific DMT study
may be included if the discharger demonstrates that the data are
applicable.
(b) Based on the new DMT measurements, the original DMT study,
and other available information, Ohio EPA may determine an appropriate
discharge-specific DMT in accordance with this rule.
(c) Ohio EPA may apply a discharge-specific DMT determined under
paragraph (G)(16)(a) or (G)(16)(b) of this rule to determine WLAs for that
discharge as required for renewal or a modification of an NPDES
permit.