South Carolina Code of Regulations
Chapter 61 - DEPARTMENT OF HEALTH AND ENVIRONMENTAL CONTROL
Subchapter 61-9 - Water Pollution Control Permits
Subchapter 61-9.403 - GENERAL PRETREATMENT REGULATIONS FOR EXISTING AND NEW SOURCES OF POLLUTION
Section 61-9.403.7 - Removal Credits
Universal Citation: SC Code Regs 61-9.403.7
Current through Register Vol. 48, No. 9, September 27, 2024
(a) Introduction.
(1) Definitions. For the
purpose of this section:
(i) "Removal" means
a reduction in the amount of a pollutant in the POTW's effluent or alteration
of the nature of a pollutant during treatment at the POTW. The reduction or
alteration can be obtained by physical, chemical or biological means and may be
the result of specifically designed POTW capabilities or may be incidental to
the operation of the treatment system. Removal as used in this subpart shall
not mean dilution of a pollutant in the POTW.
(ii) "Sludge Requirements" shall mean the
following statutory provisions and regulations or permits issued thereunder (or
more stringent local regulations): section405 of the Clean Water Act; the Solid
Waste Disposal Act (SWDA) (including Title II more commonly referred to as the
Resource Conservation and Recovery Act (RCRA) and State regulations contained
in any State sludge management plan prepared pursuant to Subtitle D of SWDA);
the Clean Air Act; the Toxic Substances Control Act; and the Marine Protection,
Research, and Sanctuaries Act, and the South Carolina Pollution Control
Act.
(2) General. Any
POTW receiving wastes from an Industrial User to which a categorical
Pretreatment Standard(s) applies may, at its discretion and subject to the
conditions of this section, grant removal credits to reflect removal by the
POTW of pollutants specified in the categorical Pretreatment Standard(s). The
POTW may grant a removal credit equal to or, at its discretion, less than its
consistent removal rate. Upon being granted a removal credit, each affected
Industrial User shall calculate its revised discharge limits in accordance with
subparagraph (4) of this paragraph. Removal credits may only be given for
indicator or surrogate pollutants regulated in a categorical Pretreatment
Standard if the categorical Pretreatment Standard so specifies.
(3) Conditions for authorization to give
removal credits. A POTW is authorized to give removal credits only if the
following conditions are met:
(i) Application.
The POTW applies for, and receives authorization from the Department to give a
removal credit in accordance with the requirements and procedures specified in
paragraph (e) of this section.
(ii)
Consistent removal determination. The POTW demonstrates and continues to
achieve consistent removal of the pollutant in accordance with paragraph (b) of
this section.
(iii) POTW local
pretreatment program. The POTW has an approved pretreatment program in
accordance with and to the extent required by this regulation; provided,
however, a POTW which does not have an approved pretreatment program may,
pending approval of such a program, conditionally give credits as provided in
paragraph (d) of this section.
(iv)
Sludge requirements. The granting of removal credits will not cause the POTW to
violate the local, State, and Federal Sludge Requirements which apply to the
sludge management method chosen by the POTW. Alternatively, the POTW can
demonstrate to the Department that even though it is not presently in
compliance with applicable Sludge Requirements, it will be in compliance when
the Industrial User(s) to whom the removal credit would apply is required to
meet its categorical Pretreatment Standard(s) as modified by the removal
credit. If granting removal credits forces a POTW to incur greater sludge
management costs than would be incurred in the absence of granting removal
credits, the additional sludge management costs will not be eligible for EPA
grant assistance. Removal credits may be made available for the following
pollutants.
(A) For any pollutant listed in
Appendix G-I for the use or disposal practice employed by the POTW, when the
requirements in R.61-9.503 for that practice
are met.
(B) For any pollutant
listed in Appendix G-II for the use or disposal practice employed by the POTW
when the concentration for a pollutant listed in Appendix G-II in the sewage
sludge that is used or disposed does not exceed the concentration for the
pollutant in Appendix G-II.
(C) For
any pollutant in sewage sludge when the POTW disposes all of its sewage sludge
in a municipal solid waste landfill unit that meets the criteria in 40 CFR Part
258 and R.61-107.
(v)
NPDES permit limitations. The granting of removal credits will not cause a
violation of the POTW's permit limitations or conditions. Alternatively, the
POTW can demonstrate to the Department that even though it is not presently in
compliance with applicable limitations and conditions in its NPDES permit, it
will be in compliance when the Industrial User(s) to whom the removal credit
would apply is required to meet its categorical Pretreatment Standard(s), as
modified by the removal credit provision.
(4) Calculation of revised discharge limits.
Revised discharge limits for a specific pollutant shall be derived by use of
the following formula:
y = x
-----
1 - r
Where:
x = pollutant discharge limit specified in the applicable categorical Pretreatment Standard
r = removal credit for that pollutant as established under paragraph (b) of this section (percentage removal expresses as a proportion, i.e., a number between 0 and 1)
y = revised discharge limit for the specified pollutant (expressed in same units as x)
(b) Establishment of Removal Credits; Demonstration of Consistent Removal.
(1)
Definition of Consistent Removal. "Consistent Removal" shall mean the average
of the lowest 50 percent of the removal measured according to paragraph (b)(2)
of this section. All sample data obtained for the measured pollutant during the
time period prescribed in paragraph (b)(2) of this section must be reported and
used in computing Consistent Removal. If a substance is measurable in the
influent but not in the effluent, the effluent level may be assumed to be the
limit of measurement, and those data may be used by the POTW at its discretion
and subject to approval by the Department. If the substance is not measurable
in the influent, the data may not be used. Where the number of samples with
concentrations equal to or above the limit of measurement is between 8 and 12,
the average of the lowest 6 removals shall be used. If there are less than 8
samples with concentrations equal to or above the limit of measurement, the
Department may approve alternate means for demonstrating Consistent Removal.
The term "measurement" refers to the ability of the analytical method or
protocol to quantify as well as identify the presence of the substance in
question.
(2) Consistent Removal
Data. Influent and effluent operational data demonstrating Consistent Removal
or other information, as provided for in paragraph (b)(1) of this section,
which demonstrates Consistent Removal of the pollutants for which discharge
limit revisions are proposed. This data shall meet the following requirements:
(i) Representative Data: Seasonal. The data
shall be representative of yearly and seasonal conditions to which the POTW is
subjected for each pollutant for which a discharge limit revision is
proposed.
(ii) Representative Data:
Quality and Quantity. The data shall be representative of the quality and
quantity of normal effluent and influent flow if such data can be obtained. If
such data are unobtainable, alternate data or information may be presented for
approval to demonstrate Consistent Removal as provided for in paragraph (b)(1)
of this section.
(iii) Sampling
Procedures: Composite.
(A) The influent and
effluent operational data shall be obtained through 24-hour flow-proportional
composite samples. Sampling may be done manually or automatically, and
discretely or continuously. For discrete sampling, at least 12 aliquots shall
be composited. Discrete sampling may be flow-proportioned either by varying the
time interval between each aliquot or the volume of each aliquot. All
composites must be flow-proportional to each stream flow at time of collection
of influent aliquot or to the total influent flow since the previous influent
aliquot. Volatile pollutant aliquots must be combined in the laboratory
immediately before analysis.
(B)
(1) Twelve samples shall be taken at
approximately equal intervals throughout one full year. Sampling must be evenly
distributed over the days of the week so as to include no-workdays as well as
workdays. If the Department determines that this schedule will not be most
representative of the actual operation of the POTW Treatment Plant, an
alternative sampling schedule will be approved.
(2) In addition, upon the Department's
concurrence, a POTW may utilize an historical data base amassed prior to the
effective date of this section provided that such data otherwise meet the
requirements of this paragraph. In order for the historical data base to be
approved, it must present a statistically valid description of daily, weekly,
and seasonal sewage treatment plant loadings and performance for at least one
year.
(C) Effluent
sample collection need not be delayed to compensate for hydraulic detention
unless the POTW elects to include detention time compensation or unless the
Department requires detention time compensation. The Department may require
that each effluent sample be taken approximately one detention time later than
the corresponding influent sample when failure to do so would result in an
unrepresentative portrayal of actual POTW operation. The detention period is to
be based on a 24-hour average daily flow value. The average daily flow used
will be based upon the average of the daily flows during the same month of the
previous year.
(iv)
Sampling Procedures: Grab. Where composite sampling is not an appropriate
sampling technique, a grab sample(s) shall be taken to obtain influent and
effluent operational data. Collection of influent grab samples should precede
collection of effluent samples by approximately one detention period. The
detention period is to be based on a 24-hour average daily flow value. The
average daily flow used will be based upon the average of the daily flows
during the same month of the previous year. Grab samples will be required, for
example, where the parameters being evaluated are those, such as cyanide and
phenol, which may not be held for any extended period because of biological,
chemical, or physical interactions which take place after sample collection and
affect the results. A grab sample is an individual sample collected over a
period of time not exceeding 15 minutes.
(v) Analytical methods. The sampling referred
to in paragraphs (b)(2)(i) through (iv) of this section and an analysis of
these samples shall be performed in accordance with the techniques prescribed
in 40 CFR Part 136 and amendments thereto. Where 40 CFR Part 136 does not
contain sampling or analytical techniques for the pollutant in question, or
where the Department determines that the Part 136 sampling and analytical
techniques are inappropriate for the pollutant in question, sampling and
analysis shall be performed using validated analytical methods or any other
applicable sampling and analytical procedures, including procedures suggested
by the POTW or other parties, approved by the Department.
(vi) Calculation of removal. All data
acquired under the provisions of this section must be submitted to the
Department. Removal for a specific pollutant shall be determined either, for
each sample, by measuring the difference between the concentrations of the
pollutant in the influent and effluent of the POTW and expressing the
difference as a percent of the influent concentration, or, where such data
cannot be obtained, Removal may be demonstrated using other data or procedures
subject to concurrence by the Department as provided for in paragraph (b)(1) of
this section.
(c) Provisional credits. For pollutants which are not being discharged currently (i.e., new or modified facilities, or production changes) the POTW may apply for authorization to give removal credits prior to the initial discharge of the pollutant. Consistent removal shall be based provisionally on data from treatability studies or demonstrated removal at other treatment facilities where the quality and quantity of influent are similar. Within 18 months after the commencement of discharge of pollutants in question, consistent removal must be demonstrated pursuant to the requirements of paragraph (b) of this section. If, within 18 months after the commencement of the discharge of the pollutant in question, the POTW cannot demonstrate consistent removal pursuant to the requirements of paragraph (b) of this section, the authority to grant provisional removal credits shall be terminated by the Department and all Industrial Users to whom the revised discharge limits had been applied shall achieve compliance with the applicable categorical Pretreatment Standard(s) within a reasonable time, not to exceed the period of time prescribed in the applicable Pretreatment Standard(s), as may be specified by the Department.
(d) Exception to POTW Pretreatment Program Requirement. A POTW required to develop a local pretreatment program by section403.8 may conditionally give removal credits pending approval of such a program in accordance with the following terms and conditions:
(1) All Industrial Users who are currently
subject to a categorical Pretreatment Standard and who wish conditionally to
receive a removal credit must submit to the POTW the information required in
section403.12(b)(1) through (7)(b)(1) through (7) (except new or modified
industrial users must only submit the information required by
section403.12(b)(1) through (6)(b)(1) through (6), pertaining to the
categorical Pretreatment Standard as modified by the removal credit. The
Industrial Users shall indicate what additional technology, if any, will be
needed to comply with the categorical Pretreatment Standard(s) as modified by
the removal credit:
(2) The POTW
must have submitted to the Department an application for pretreatment program
approval meeting the requirements of section403.8 and section403.9 in a timely
manner, not to exceed the time limitation set forth in a compliance schedule
for development of a pretreatment program included in the POTW's NPDES permit,
but in no case later than July 1, 1983, where no permit deadline
exists:
(3) The POTW must:
(i) Compile and submit data demonstrating its
consistent removal in accordance with paragraph (b) of this section;
(ii) Comply with the conditions specified in
paragraph (a)(3) of this section; and
(iii) Submit a complete application for
removal credit authority in accordance with paragraph (e) of this
section.
(4) If a POTW
receives authority to grant conditional removal credits and the Department
subsequently makes a final determination, after appropriate notice, that the
POTW failed to comply with the conditions in paragraphs (d)(2) and (3) of this
section, the authority to grant conditional removal credits shall be terminated
by the Department and all Industrial Users to whom the revised discharge limits
had been applied shall achieve compliance with the applicable categorical
Pretreatment Standard(s) within a reasonable time, not to exceed the period of
time prescribed in the applicable categorical Pretreatment Standard(s), as may
be specified by the Department.
(5)
If a POTW grants conditional removal credits and the POTW or the Department
subsequently makes a final determination, after appropriate notice, that the
Industrial User(s) failed to comply with the conditions in paragraph (d)(1) of
this section, the conditional credit shall be terminated by the POTW or the
Department for the non-complying Industrial User(s) and the Industrial User(s)
to whom the revised discharge limits had been applied shall achieve compliance
with the applicable categorical Pretreatment Standard(s) within a reasonable
time, not to exceed the period of time prescribed in the applicable categorical
Pretreatment Standard(s), as may be specified by the Department. The
conditional credit shall not be terminated where a violation of the provisions
of this paragraph results from causes entirely outside of the control of the
Industrial User(s) or the Industrial User(s) had demonstrated substantial
compliance.
(6) The Department may
elect not to review an application for conditional removal credit authority
upon receipt of such application, in which case the conditionally revised
discharge limits will remain in effect until reviewed by the Department. This
review may occur at any time in accordance with the procedures of
section403.11, but in no event later than the time of any pretreatment program
approval or any NPDES permit reissuance thereunder.
(e) POTW application for authorization to give removal credits and Department review.
(1) Who must apply. Any POTW that wants to
give a removal credit must apply for authorization from the
Department.
(2) To whom application
made. An application for authorization to give removal credits (or modify
existing ones) shall be submitted by the POTW to the Department.
(3) When to apply. A POTW may apply for
authorization to give or modify removal credits at any time.
(4) Contents of the Application. An
application for authorization to give removal credits must be supported by the
following information:
(i) List of pollutants.
A list of pollutants for which removal credits are proposed.
(ii) Consistent Removal Data. The data
required pursuant to paragraph (b) of this section.
(iii) Calculation of revised discharge
limits. Proposed revised discharge limits for each affected subcategory of
Industrial Users calculated in accordance with paragraph (a)(4) of this
section.
(iv) Local Pretreatment
Program Certification. A certification that the POTW has an approved local
pretreatment program or qualifies for the exception to this requirement found
at paragraph (d) of this section.
(v) Sludge Management Certification. A
specific description of the POTW's current methods of using or disposing of its
sludge and a certification that the granting of removal credits will not cause
a violation of the sludge requirements identified in paragraph (a)(3)(iv) of
this section.
(vi) NPDES Permit
Limit Certification. A certification that the granting of removal credits will
not cause a violation of the POTW's NPDES permit limits and conditions as
required in paragraph (a)(3)(v) of this section.
(5) Department Review. The Department shall
review the POTW's application for authorization to give or modify removal
credits in accordance with the procedures of section403.11 and shall, in no
event, have more than 180 days from public notice of an application to complete
review.
(6) EPA review of State
removal credit approvals. The Regional Administrator may agree in the
Memorandum of Agreement under 40 CFR Part 123.24(d) to waive the right to
review and object to submissions for authority to grant removal credits. Such
an agreement shall not restrict the Regional Administrator's right to comment
upon or object to permits issued to POTW's except to the extent
R.61-9.122.24(d)(d)allows such restriction.
(7) Nothing in these regulations precludes an
Industrial User or other interested party from assisting the POTW in preparing
and presenting the information necessary to apply for authorization.
(f) Continuation and withdrawal of authorization.
(1) Effect of authorization.
(i) Once a POTW has received authorization to
grant removal credits for a particular pollutant regulated in a categorical
Pretreatment Standard, it may automatically extend that removal credit to the
same pollutant when it is regulated in other categorical standards, unless
granting the removal credit will cause the POTW to violate the sludge
requirements identified in (a)(3)(iv) of this section or its NPDES permit
limits and conditions as required by (a)(3)(v). If a POTW elects at a later
time to extend removal credits to a certain categorical Pretreatment Standard,
industrial subcategory or one or more Industrial Users that initially were not
granted removal credits, it must notify the Department.
(ii) [Reserved]
(2) Inclusion in POTW permit. Once authority
is granted, the removal credits shall be included in the POTW's NPDES Permit as
soon as possible and shall become an enforceable requirement of the POTW's
NPDES permit. The removal credits will remain in effect for the term of the
POTW's NPDES permit, provided the POTW maintains compliance with the conditions
specified in paragraph (f)(4) of this section.
(3) Compliance monitoring. Following
authorization to give removal credits, a POTW shall continue to monitor and
report on (at such intervals as may be specified by the Department, but in no
case less than once per year) the POTW's removal capabilities. A minimum of one
representative sample per month during the reporting period is required, and
all sampling data must be included in the POTW's compliance report.
(4) Modification or withdrawal of removal
credits.
(i) Notice of POTW. The Department
shall notify the POTW if, on the basis of pollutant removal capability reports
received pursuant to paragraph (f)(3) of this section or other relevant
information available to it, the Department determines:
(A) That one or more of the discharge limit
revisions made by the POTW itself, no longer meets the requirements of this
section, or
(B) That such discharge
limit revisions are causing a violation of any conditions or limits contained
in the POTW's NPDES Permit.
(ii) Corrective Action. If appropriate
corrective action is not taken within a reasonable time, not to exceed 60 days
unless the POTW or the affected Industrial Users demonstrate that a longer time
period is reasonably necessary to undertake the appropriate corrective action,
the Department shall either withdraw such discharge limits or require
modifications in the revised discharge limits.
(iii) Public notice of withdrawal or
modification. The Department shall not withdraw or modify revised discharge
limits unless it shall first have notified the POTW and all Industrial Users to
whom revised discharge limits have been applied, and made public, in writing,
the reasons for such withdrawal or modification, and an opportunity is provided
for a hearing. Following such notice and withdrawal or modification, all
Industrial Users to whom revised discharge limits has been applied, shall be
subject to the modified discharge limits or the discharge limits prescribed in
the applicable categorical Pretreatment Standards, as appropriate, and shall
achieve compliance with such limits within a reasonable time (not to exceed the
period of time prescribed in the applicable categorical Pretreatment
Standard(s)) as may be specified by the Department.
(g) Removal credits in State-run pretreatment programs under section403.10(e)(e). Where the Department elects to implement a local pretreatment program in lieu of requiring the POTW to develop such a program (as provided in section403.10(e)(e), the POTW will not be required to develop a pretreatment program as a precondition to obtaining authorization to give removal credits. The POTW will, however, be required to comply with the other conditions of paragraph (a)(3) of this section.
(h) Compensation for Overflow. "Overflow" means the intentional or unintentional diversion of flow from the POTW before the POTW Treatment Plant. POTW which at least once annually overflow untreated wastewater to receiving waters may claim Consistent Removal of a pollutant only by complying with either paragraphs (h)(1) or (h)(2) of this section. However, paragraph (h) of this section shall not apply where Industrial User(s) can demonstrate that Overflow does not occur between the Industrial User(s) and the POTW Treatment Plant;
(1) The Industrial User
provides containment or otherwise ceases or reduces Discharges from the
regulated processes which contain the pollutant for which an allowance is
requested during all circumstances in which an Overflow event can reasonably by
expected to occur at the POTW or at a sewer to which the Industrial User is
connected. Discharges must cease or e reduced, or pretreatment must be
increased, to the extent necessary to compensate for the removal not being
provided by the POTW. Allowances under this provision will only be granted
where the POTW submits to the Department evidence that:
(i) All Industrial Users to which the POTW
proposes to apply this provision have demonstrated the ability to contain or
otherwise cease or reduce, during circumstances in which an Overflow event can
reasonably be expected to occur. Discharges from the regulated processes which
contain pollutants for which an allowance is requested:
(ii) The POTW has identified circumstances in
which an Overflow event can reasonably be expected to occur, and has a
notification or other viable plan to insure that Industrial Users will learn of
an impending Overflow in sufficient time to contain, cease, or reduce
Discharging to prevent untreated Overflows from occurring. The POTW must also
demonstrate that it will monitor and verify the data required in paragraph
(h)(1)(iii) of this section, to insure that Industrial Users are containing,
ceasing, or reducing operations during POTW System Overflow; and
(iii) All Industrial Users to which the POTW
proposes to apply this provision have demonstrated the ability and commitment
to collect and make available, upon request by the POTW, Department, or EPA
Regional Administrator, daily flow reports or other data sufficient to
demonstrate that all Discharges from regulated processes containing the
pollutant for which the allowance is requested were contained, reduced, or
otherwise ceased, as appropriate, during all circumstances in which an Overflow
event was reasonably expected to occur; or
(2)
(i) The
Consistent Removal claimed is reduced pursuant to the following equation:
rc = rm 8760 - Z
--------
8760
Where:
rm = POTW's Consistent Removal rate for that pollutant as established under paragraphs (a)(1) and (b)(2) of this section
rc = removal corrected by the Overflow factor
Z = hours per year that overflow occurred between the Industrial User(s) and the POTW Treatment Plant, the hours either to be shown in the POTW's current NPDES permit application or the hours, as demonstrated by verifiable techniques, that a particular Industrial User's Discharge overflows between the Industrial User and the POTW Treatment Plant; and
(ii) [Reserved.]
(iii) [Reserved.]
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