401 KAR 5:057. KPDES pretreatment requirements.

401 KAR 5:057. KPDES pretreatment requirements.

RELATES TO: KRS 224.01-010, 224.01-070, 224.01-400, 224.70-100, 224.70-120, 224.99-010, 40 C.F.R. 1.25(e), 25, 130, 131, 136, 258, 261, Chapter I, Subchapter N, 401 et seq., 403 Appendices A, D, 503, 33 U.S.C. 1251 et seq., 1288, 1314(h), 1317(d), 1319(c)(4), (6), 1370, 1718, 1919(f), 42 U.S.C. 6901 et seq.

STATUTORY AUTHORITY: KRS 224.10-100, 224.16-050, 224.70-110, 224.73-120, 40 C.F.R. 1.25(e), 25, 130, 131, 136, 258, 261, Chapter I, Subchapter N, 401 et seq., 403 Appendices A, D, 503, 33 U.S.C. 1251 et seq., 1288, 1314(h), 1317(d), 1319(c)(4), (6), 1342, 1370, 42 U.S.C. 6901 et seq.

NECESSITY, FUNCTION, AND CONFORMITY: This administrative regulation implements Sections 204(b)(1)(c), 208(b)(2)(c)(iii), 301(b)(1)(A)(ii), 301(b)(2)(A)(ii), 301(h)(5) and 301(i)(2), 304(e) and (g), 307, 308, 309, 402(b), 405, and 501(a) of the Federal Water Pollution Control Act of 1977 (PL 95-217) or "the Act." It establishes responsibilities of the Commonwealth of Kentucky, local government, industry, and the public to implement the national pretreatment program to control pollutants which pass through or interfere with treatment processes in publicly owned treatment works (POTWs) or which may contaminate sewage sludge. Its objectives are to prevent the introduction of pollutants into POTWs which will interfere with the operation of a POTW, including interference with its use or disposal of municipal sludge; to prevent the introduction of pollutants into POTWs which will pass through the treatment works or otherwise be incompatible with the treatment works; and to improve opportunities to recycle and reclaim municipal and industrial wastewaters and sludges.

Section 1. Applicability. (1) This administrative regulation shall apply to:

(a) Pollutants from nondomestic sources which are discharged into or transported by truck or rail or otherwise introduced into POTWs;

(b) POTWs which receive wastewater from sources subject to national pretreatment standards; and

(2) This administrative regulation shall not apply to sources which lawfully discharge to a sewer which is not connected to a POTW treatment plant.

Section 2. Local Law. This administrative regulation shall not affect any pretreatment requirements, including any standards or prohibitions, established by local law as long as local requirements are not less stringent than those set forth in state or national pretreatment standards, or other requirements or prohibitions established under the Act or this administrative regulation.

Section 3. Pretreatment Standards: Prohibited Discharges. (1)(a) General prohibition. A user may not introduce into a POTW any pollutant which causes pass-through or interference. This general prohibition and the specific prohibitions in subsection (2) of this section shall apply to each user introducing pollutants into a POTW whether or not the user is subject to other national pretreatment standards or national or local pretreatment requirements.

(b) Affirmative defenses. A user shall have an affirmative defense in action brought against it alleging a violation of the general prohibitions established in paragraph (a) of this subsection and the specific prohibitions in subsection (2) of this section if the user demonstrates that:

1. It did not know or have reason to know that its discharge, alone or in conjunction with discharges from other sources, would cause pass-through or interference; and

2.a. A local limit designed to prevent pass-through or interference was developed in accordance with subsection (3) of this section for each pollutant in the user's discharge that caused pass-through or interference, and the user was in compliance with each local limit directly prior to and during the pass-through or interference; or

b. If a local limit designed to prevent pass- through or interference has not been developed in accordance with subsection (3) of this section for the pollutant that caused the pass-through or interference, the user's discharge directly prior to and during the pass-through or interference did not change substantially in nature or constituents from the user's prior discharge activity when the POTW was regularly in compliance with the POTW's KPDES permit requirements and, if the violation was interference, was in compliance with applicable requirements for sewage sludge use or disposal.

(2) Specific prohibitions. In addition, the following pollutants shall not be introduced into a POTW:

(a) Pollutants which create a fire or explosion hazard in the POTW, including, but not limited to, waste streams with a closed cup flashpoint of less than 140 degrees Fahrenheit (°F) or sixty (60) degrees Celsius (°C) using the test methods specified in 40 CFR 261.21;

(b) Pollutants which may cause corrosive structural damage to the POTW, but no discharges with pH lower than five and zero-tenths (5.0), unless the POTW is specifically designed to accommodate the discharges;

(c) Solid or viscous pollutants in amounts which would cause obstruction to the flow in the POTW resulting in interference;

(d) Pollutants, including oxygen demanding pollutants (biochemical oxygen demand (BOD), etc.) released in a discharge at a flow rate or pollutant concentration which would cause interference with the POTW;

(e) Heat in amounts which would inhibit biological activity in the POTW resulting in interference, but no heat in quantities such that the temperature at the POTW treatment plant exceeds forty (40) °C (104 °F) unless the cabinet, upon request of the POTW, approves alternate temperature limits;

(f) Petroleum oil, nonbiodegradable cutting oil, or products of mineral oil origin in amounts that would cause interference or pass-through;

(g) Pollutants which result in the presence of toxic gases, vapors, or fumes within the POTW in a quality that may cause acute worker health and safety problems; or

(h) Trucked or hauled pollutants, except at discharge points designated by the POTW.

(3) The POTW shall develop specific limits under the following conditions:

(a) Each POTW developing a pretreatment program pursuant to Section 6 of this administrative regulation shall develop and enforce specific limits to implement the prohibitions listed in subsections (1) and (2) of this section. Each POTW with an approved pretreatment program shall continue to develop these limits as necessary and effectively enforce the limits.

(b) All other POTWs, if pollutants contributed by users result in interference or pass-through, and the violation is likely to recur, shall develop and enforce specific limits for industrial users, and all other users as appropriate, which, together with appropriate changes in the POTW's treatment plant's facilities or operation, are necessary to ensure renewed and continued compliance with the POTW's KPDES permit or sludge use or disposal practices.

(c) Specific effluent limits shall not be developed and enforced without individual notice to persons or groups who have requested these notices and had an opportunity to respond.

(4) Local limits. If specific prohibitions or limits on pollutants or pollutant parameters are developed by a POTW in accordance with subsection (3) of this section, the limits shall be deemed pretreatment standards for the purposes of Section 307(d) of the Act, 33 USC Sec. 1317(d).

(5) EPA and cabinet enforcement actions under Section 309(f) of the Clean Water Act, 33 USC Sec. 1319(f). If, within thirty (30) days after notice of an interference or pass-through violation has been sent by EPA or the cabinet to the POTW and the persons or groups who have requested these notices, the POTW fails to commence appropriate enforcement action to correct the violations, EPA or the cabinet may take appropriate enforcement action under the authority provided in Section 309(f) of the Act.

Section 4. National Pretreatment Standards: Categorical Standards. National pretreatment standards specifying quantities or concentrations of pollutants or pollutant properties which may be discharged to a POTW by existing or new industrial users in specific industrial subcategories are established as separate federal regulations under the appropriate subpart of 40 CFR Chapter I, Subchapter N. These standards, unless specifically noted otherwise, shall be in addition to all applicable pretreatment standards and requirements set forth in this administrative regulation.

(1) Category determination request.

(a) Application deadline. Within sixty (60) days after the effective date of a pretreatment standard for a subcategory under which an industrial user may be included, the industrial user or POTW may request that the cabinet provide written certification on whether the industrial user falls within that particular subcategory. If an existing industrial user adds or changes a process or operation which may be included in a subcategory, the existing industrial user shall request this certification prior to commencing discharge from the added or changed processes or operation. A new source shall request this certification prior to commencing discharge. If a request for certification is submitted by a POTW, the POTW shall notify affected industrial users of the submission. The industrial user may provide written comments on the POTW submission to the cabinet, within thirty (30) days of notification.

(b) Contents of application. Each request shall contain a statement:

1. Describing which subcategories might be applicable; and

2. Citing evidence and reasons why a particular subcategory is applicable and why others are not applicable. The person signing the application statement submitted pursuant to this section shall make the following certification: "I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations."

(c) Deficient requests. The cabinet shall act only on written requests for determinations that contain all of the information required. Persons who have made incomplete submissions shall be notified by the cabinet that their requests are deficient and, unless the time period is extended, will be given thirty (30) days to correct the deficiency. If the deficiency is not corrected within thirty (30) days or within an extended period allowed by the cabinet, the request for a determination shall be denied.

(d) Final decision.

1. If the cabinet receives a submittal the cabinet shall, after determining that it contains all of the information required by paragraph (b) of this subsection, consider the submission, additional evidence that may have been requested, and other available information relevant to the request. The cabinet shall then make a written determination of the applicable subcategory and state the reasons for the determination.

2. If the request is submitted to the cabinet, the cabinet shall forward the determination described in this paragraph to EPA which may make a final determination. EPA may waive receipt of these determinations. If EPA does not modify the cabinet's decision within sixty (60) days after receipt thereof, or if EPA waives receipt of the determination, the cabinet's decision shall be final.

3. If the request is submitted by the industrial user or POTW to EPA or if EPA elects to modify the cabinet's decision, EPA's decision shall be final.

4. EPA or the cabinet, as appropriate, shall send a copy of the determination to the affected industrial user and the POTW. If the final determination is made by EPA, EPA shall send a copy of the determination to the cabinet.

(e) Requests for hearing or legal decision. Within thirty (30) days following the date of receipt of notice of the final determination as provided for by paragraph (d) of this subsection, the requester may submit a petition to reconsider or contest the decision to the EPA regional administrator who shall act on the petition expeditiously and state the reasons for the determination in writing.

(2) Deadline for compliance with categorical standards. Compliance by existing sources with categorical pretreatment standards shall be within three (3) years of the date the standard is effective unless a shorter compliance time is specified in the appropriate subpart of 40 CFR Chapter I, Subchapter N. Direct dischargers with KPDES permits modified or reissued to provide a variance pursuant to Section 301(i)(2) of the Act, 33 USC 1311(i)(2) shall meet compliance dates set in applicable categorical pretreatment standards. Existing sources which become industrial users subsequent to promulgation of an applicable categorical pretreatment standard shall be considered existing industrial users unless the sources meet the definition of a new source. New sources shall install and have in operating condition, and shall start up all pollution control equipment required to meet applicable pretreatment standards before beginning to discharge. Within the shortest feasible time, not to exceed ninety (90) days, new sources shall meet all applicable pretreatment standards.

(3)(a) Concentration and mass limits. Pollutant discharge limits in categorical pretreatment standards shall be expressed either as concentration or mass limits. If possible, if concentration limits are specified in standards, equivalent mass limits will be provided so that local, cabinet, or federal authorities responsible for enforcement may use either concentration or mass limits. Limits in categorical pretreatment standards shall apply to the effluent of the process regulated by the standard, or as otherwise specified by the standard.

(b) If the limits in a categorical pretreatment standard are expressed only in terms of mass of pollutant per unit of production, the control authority may convert the limits to equivalent limitations expressed either as mass of pollutant discharged per day or effluent concentration for purposes of calculating effluent limitations applicable to individual industrial users.

(c) A control authority calculating equivalent mass per day limitations under paragraph (b) of this subsection shall calculate the limitations by multiplying the limits in the standard by the industrial user's average rate of production. This average rate of production shall be based not upon the designed production capacity but rather upon a reasonable measure of the industrial user's actual long term daily production, such as the average daily production during a representative year. For new sources, actual production shall be estimated using projected production.

(d) A control authority calculating equivalent concentration limitations under paragraph (b) of this subsection shall calculate the limitations by dividing the mass limitations derived under paragraph (c) of this subsection by the average daily flow rate of the industrial user's regulated process wastewater. This average daily flow rate shall be based upon a reasonable measure of the industrial user's actual long term average flow rate, such as the average daily flow rate during the representative year.

(e) Equivalent limitations calculated in accordance with paragraphs (c) and (d) of this subsection shall be deemed pretreatment standards for the purposes of Section 307(d) of the Act, 33 USC 1317(d) and this administrative regulation. Industrial users shall comply with the equivalent limitations in lieu of the promulgated categorical standards from which the equivalent limitations were derived.

(f) Many categorical pretreatment standards specify one (1) limit for calculating maximum daily discharge limitations and a second limit for calculating maximum monthly average, or four (4) day average, limitations. If these standards are being applied, the same production of flow figure shall be used in calculating both types of equivalent limitations.

(g) Industrial users operating under a control mechanism incorporating equivalent mass or concentration limits calculated from a production based standard shall notify the control authority within two (2) business days after the user has a reasonable basis to know that the production level will significantly change within the next calendar month. A user not notifying the control authority of an anticipated change shall meet the mass or concentration limits in its control mechanism that were based on the original estimate of the long term average production rate.

(4) Dilution prohibited as substitute for treatment. Unless expressly authorized to do so by an applicable pretreatment standard or requirement, no industrial user shall ever increase the use of process water, or in other ways attempt to dilute a discharge as a partial or complete substitute for adequate treatment to achieve compliance with a pretreatment standard or requirement. The control authority may impose mass limitations on industrial users which are using dilution to meet applicable pretreatment standards or requirements, or in other cases if the imposition of mass limitations is appropriate.

(5) Combined waste stream formula. If process effluent is mixed prior to treatment with wastewaters other than those generated by the regulated process, fixed alternative discharge limits may be derived by the control authority, or by the industrial user with the written concurrence of the control authority. These alternative limits shall be applied to the mixed effluent. When deriving alternative categorical limits, the control authority or industrial user shall calculate both an alternative daily maximum value using the daily maximum values specified in the appropriate categorical pretreatment standards and an alternative consecutive sampling day average value using the monthly average values specified in the appropriate categorical pretreatment standards. The industrial user shall comply with the alternative daily maximum and monthly average limits fixed by the control authority until the control authority modifies the limits or approves an industrial user modification request. Modification shall be authorized if there is a material or significant change in the values used in the calculation to fix alternative limits for the regulated pollutant. An industrial user shall immediately report the material or significant changes to the control authority. If appropriate, new alternative categorical limits shall be calculated within thirty (30) days.

(a) Alternative limit calculation. Either of the formulas in subparagraph 2 or 3 of this paragraph shall be used for deriving an alternative limit for a specified pollutant.

1. The average daily flow (F_D) shall be a reasonable measure of the average daily flow for a thirty (30) day period from the following sources; for new sources, flows shall be estimated using projected values:

a. Boiler blowdown streams, noncontact cooling streams, storm water streams, and demineralizer backwash streams. However, if these streams contain a significant amount of a pollutant, and the combination of these streams, prior to treatment, with an industrial user's regulated process waste streams will result in a substantial reduction of that pollutant, the control authority, upon application of the industrial user, may determine whether these streams should be classified as diluted or unregulated. In its application to the control authority, the industrial user shall provide engineering, production, sampling, and analysis and other information necessary so that the control authority is able to make its determination;

b. Sanitary waste streams that are not regulated by a categorical pretreatment standard; or

c. From process waste streams which were or could have been entirely exempted from categorical pretreatment standards by the U.S. EPA for one (1) or more of the following reasons, and are listed in 40 CFR Part 403, Appendix D:

(i) The pollutants of concern are not detectable in the effluent from the industrial user;

(ii) The pollutants of concern are present only in trace amounts and are neither causing nor likely to cause toxic effects;

(iii) The pollutants of concern are present in amounts too small to be effectively reduced by technologies known to the U.S. EPA administrator; or

(iv) The waste stream contains only pollutants which are compatible with the POTW.

2. Alternative concentration limit.

where:

C_T = the alternative concentration limit for the combined waste stream.

C_i = the categorical pretreatment standard concentration limit for a pollutant in the regulated stream i.

F_i = the average daily flow, at least a thirty (30) day average, of stream i to the extent that it is regulated for the pollutant.

F_D = the average daily flow, at least a thirty (30) day average, from subparagraph 1 of this paragraph.

F_T = the average daily flow, at least a thirty (30) day average, through the combined treatment facility, including F_i, F_D and unregulated streams.

N = the total number of regulated streams.

3. Alternative mass limit.

where:

M_T = the alternative mass limit for a pollutant in the combined waste stream.

M_i = the categorical pretreatment standard mass limit for a pollutant in the regulated stream i, or the categorical pretreatment mass limit multiplied by the appropriate measure of production.

F_i = the average flow, at least a thirty (30) day average, of stream i to the extent that it is regulated for the pollutant.

F_D = the average daily flow, at least a thirty (30) day average, from subparagraph 1 of this paragraph.

F_T = the average daily flow, at least a thirty (30) day average, through the combined treatment facility, including F_i, F_D and unregulated streams.

N = the total number of regulated streams.

(b) Alternate limits below detection limit. An alternative pretreatment limit from paragraph (a) of this subsection shall not be used if the alternative limit is below the analytical detection limit for any of the regulated pollutants.

(c) Self-monitoring. Self-monitoring required to insure compliance with the alternative categorical limit shall be conducted in accordance with the requirements set forth in Section 9 of this administrative regulation.

(d) Choice of monitoring location. If a treated regulated process waste stream is combined prior to treatment with wastewaters other than those generated by the regulated process, the industrial user may monitor either the segregated process waste stream or the combined waste stream for the purpose of determining compliance with applicable pretreatment standards. If the industrial user chooses to monitor the segregated process waste stream, it shall apply the applicable categorical pretreatment standard. If the user chooses to monitor the combined waste stream, it shall apply an alternative discharge limit calculated using the combined waste stream formula as provided in this section. The industrial user may change monitoring points only after receiving approval from the control authority. The control authority shall ensure that a change in an industrial user's monitoring points will not allow the user to substitute dilution for adequate treatment to achieve compliance with applicable standards.

Section 5. Removal Credits. (1)(a) General. Any POTW receiving wastes from an industrial user to which a categorical pretreatment standard applies may, subject to the conditions of this section, grant removal credits to reflect removal by the POTW of pollutants specified in the categorical pretreatment standards. The POTW may grant a removal credit equal to or 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 paragraph (c) of this subsection. Removal credits may be given only for indicator or surrogate pollutants regulated in a categorical pretreatment standard if the categorical pretreatment standard so specifies.

(b) Conditions for authorization to give removal credits. A POTW may give removal credits only if the following conditions are met:

1. Application. The POTW applies for, and receives, authorization from the cabinet to give a removal credit in accordance with the requirements and procedures specified in subsection (5) of this section.

2. Consistent removal determination. The POTW demonstrates and continues to achieve consistent removal of the pollutant in accordance with subsection (2) of this section.

3. POTW local pretreatment program. The POTW has an approved pretreatment program in accordance with and to the extent required by this administrative regulation; except, a POTW which does not have an approved pretreatment program may, pending approval of this type of program, conditionally give credits as provided in subsection (4) of this section.

4. Sludge requirements. The granting of removal credits shall not cause the POTW to violate KRS Chapter 224 and administrative regulations promulgated pursuant thereto, or the local and federal sludge requirements which apply to the sludge management method chosen by the POTW. Alternatively, the POTW may demonstrate to the cabinet that even though it is not presently in compliance with applicable sludge requirements, it will be in compliance if the industrial users to whom the removal credit would apply are required to meet their categorical pretreatment standards 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 shall not be eligible for EPA grant assistance. Removal credits may be made available for the following pollutants:

a.(i) For any of the pollutants listed in this clause for the use or disposal practice employed by the POTW when the requirements in 40 CFR Part 503 are met:

Pollutants	Use or Disposal Practice
Pollutants	LA¹	SD²	I³
Arsenic	X	X	X
Beryllium			X
Cadmium	X		X
Chromium	X	X	X
Copper	X
Lead	X		X
Mercury	X		X
Molybdenum	X
Nickel	X	X	X
Selenium	X
Zinc	X
Total hydrocarbons, if the hydrocarbon is listed below.			X

where:

LA - Land application;

SD - Surface disposal site without a liner and leachate collection system; and

I - Firing of sewage sludge in a sewage sludge incinerator.

(ii) The following organic pollutants are eligible for a removal credit if the requirements for total hydrocarbons in 40 CFR Part 503, Subpart E are met when sewage sludge is fired in a sewage sludge incinerator:

i. Acrylonitrile;

ii. Aldrin or dieldrin, or both (Total);

iii. Benzene;

iv. Benzidine;

v. Benzo(a)pyrene;

vi. Bis(2-chloroethyl)ether;

vii. Bis(2-ethylhexyl)phthalate;

viii. Bromodichloromethane;

ix. Bromoethane;

x. Bromoform;

xi. Carbon tetrachloride;

xii. Chlordane;

xiii. Chloroform;

xiv. Chloromethane;

xv. DDD, DDE, DDT;

xvi. Dibromochloromethane;

xvii. Dibutyl phthalate;

xviii. 1,2-dichloroethane;

xix. 1,1-dichloroethylene;

xx. 2,4-dichlorophenol 1,3-dichloropropene;

xxi. Diethyl phthalate;

xxii. 2,4-dinitrophenol;

xxiii. 1,2-diphenylhydrazine;

xxiv. Di-n-butyl phthalate;

xxv. Endosulfan;

xxvi. Endrin;

xxvii. Ethylbenzene;

xxviii. Heptachlor;

xxix. Heptachlor epoxide;

xxx. Hexachlorobutadiene;

xxxi. Alpha-hexachlorocyclohexane;

xxxii. Betahexachlorocyclohexane;

xxxiii. Hexachlorocyclopentadiene;

xxxiv. Hexachloroethane;

xxxv. Hydrogen cyanide;

xxxvi. Isophorone;

xxxvii. Lindane;

xxxviii. Methylene chloride;

xxxix. Nitrobenzene;

xl. N-Nitrosodimethylamine;

xli. N-Nitrosodi-n-propylamine;

xlii. Pentachlorophenol;

xliii. Phenol;

xliv. Polychlorinated biphenyls;

xlv. 2,3,7,8-tetrachlorodibenzo-p-dioxin;

xlvi. 1,1,2,2,-tetrachloroethane;

xlvii. Tetrachloroethylene;

xlviii. Toluene;

il. Toxaphene;

l. Trichloroethylene;

li. 1,2,4-Trichlorobenzene;

lii. 1,1,1-Trichloroethane;

liii. 1,1,2-Trichloroethane; and

liv. 2,4,6-Trichlorophenol.

b. For any of the additional pollutants listed below for the use or disposal practice employed by the POTW if the concentration for a pollutant listed below in the sewage sludge that is used or disposed does not exceed the given concentration for that pollutant in milligrams per kilogram, dry weight basis.

Pollutant	Use or Disposal Practice
		SD
	LA	Unlined¹	Lined²	I
Arsenic			³100
Aldrin or Dieldrin or both (Total)	2.7
Benzene	³16	140	3400
Benzo(a)pyrene	15	³100	³100
Bis(2-ethylhexyl)phthtlate		³100	100
Cadmium		³100	³100
Chlordane	86	³100	³100
Chromium			³100
Copper		³46	³100	1400
DDD, DDE, DDT (Total)	1.2	2000	2000
2,4 Dichlorophenoxy- acetic acid		7	7
Fluoride	730
Heptachlor	7.4
Hexachlorobenzene	29
Hexachlorobutadine	600
Iron	³78
Lead		³100	³100
Lindane	84	³28	³28
Malathion		0.63	0.63
Mercury		³100	³100
Molybdenum		40	40
Nickel			³100
N-Nitrosodimethylamine	2.1	0.088	0.088
Pentachlorophenol	30
Phenol		82	82
Polychlorinated biphenyls	4.6	<50	<50
Selenium		4.8	4.8	4.8
Toxaphene	10	³26	³26
Trichloroethylene	³10	9500	³10
Zinc		4500	4500	4500

where:

LA - Land application;

SD - Surface disposal;

I - Incineration;

¹ - Sewage sludge unit without a liner and leachate collection system;

² - Sewage sludge unit with a liner and leachate collection system; and

³ - Value expressed in grams per kilogram, dry weight basis.

c. For any pollutant in sewage sludge if the POTW disposes all of its sewage sludge in a municipal solid waste landfill unit that meets the criteria in 40 CFR Part 258.

5. KPDES permit limitations. The granting of removal credits shall not cause a violation of the POTW's permit limitations or conditions. Alternatively, the POTW may demonstrate to the cabinet that even though it is not presently in compliance with applicable limitations and conditions in its KPDES permit, it will be in compliance if the industrial users to whom the removal credit would apply are required to meet their categorical pretreatment standards, as modified by the removal credit provision.

(c) Calculation of revised discharge limits. Revised discharge limits for a specific pollutant shall be derived by use of the following formula:

where:

x = pollutant discharge limit specified in the applicable categorical pretreatment standard;

r = removal credit for that pollutant as established under subsection (2) of this section; percentage removal expressed as a proportion; i.e., a number between zero and one (1); and

y = revised discharge limit for the specified pollutant, expressed in same units as x.

(2) Establishment of removal credits; demonstration of consistent removal.

(a) Consistent removal. Consistent removal shall be the average of the lowest fifty (50) percent of the removal measured according to paragraph (b) of this subsection. All sample data obtained for the measured pollutant during the time period prescribed in paragraph (b) of this subsection shall 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 subject to approval by the cabinet. If the substance is not measurable in the influent, the data shall not be used. If the number of samples with concentrations equal to or above the limit of measurement is between eight (8) and twelve (12), the average of the lowest six (6) removals shall be used. If there are less than eight (8) samples with concentrations equal to or above the limit of measurement, the cabinet may approve alternate means for demonstrating consistent removal. Measurement shall refer to the ability of the analytical method or protocol to quantify as well as identify the presence of the substance in question.