Mo. Code Regs. tit. 10 § 20-7.015

Current through Register Vol. 49, No. 9, May 1, 2024

Section 10 CSR 20-7.015 - Effluent Regulations

PURPOSE: This amendment modifies the definition of losing streams for consistency with 10 CSR 20-7.031, directly incorporates language regarding permitting activities related to losing streams previously located in 10 CSR 20-7.031, incorporates requirements for water reuse discharges, and adds statewide nutrient reduction requirements for point sources that typically discharge nutrients and have design flows greater than 1,000,000 gallons per day; these total phosphorus nutrient reductions are neither water quality based effluent limits nor technology based effluent limits.

(1) Designations of Waters of the State.

(A) Definitions.

1. Acute Toxicity Test-a test used to determine the concentration of an effluent that causes an adverse effect (usually death) in a group of test organisms during a short-term exposure.

2. Allowable Effluent Concentration-the concentration of a toxicant or the parameter toxicity in the receiving water after mixing, sometimes referred to as the receiving water concentration or the in-stream waste concentration.

3. Chronic Toxicity Test- a short-term test, usually ninety-six (96) hours or longer in duration, in which sublethal effects such as reduced growth or reproduction rates are measured in addition to lethality.

4. Nutrient Credits are reductions that can be generated and used to achieve compliance with nutrient target reduction levels or other nutrient limitations, as follows:

A. For point sources, a reduction in discharges of nutrients in pounds that is greater than the reduction required by law or permit conditions or aggregate assessment for facilities under common ownership or operational control; or

B. For nonpoint sources with established load allocations, an actual reduction in discharge of nutrients in pounds that is greater than the reduction necessitated by the load allocation; or

C. For other nonpoint sources, an actual reduction in discharges of nutrients, for example a nonpoint source installing best management practices.

5. Representative Sample-a small quantity whose characteristics represent the nature and volume of the whole as described in 40 CFR Part 122.48 , September 26, 1984, as published by the Office of the Federal Resister, National Archives and Records Administration, 700 Pennsylvania Avenue, Washington, DC 20408, which is hereby incorporated by reference and does not include later amendments or additions.

6. Toxic Unit-a measure of effluent toxicity generally expressed as acute toxicity unit or chronic toxicity unit. The larger the toxicity unit, the greater the toxicity.

7. Toxic Unit-Acute-one-hundred (100) times the reciprocal of the effluent concentration that causes fifty percent (50%) of the organisms to die in an acute toxicity test.

8. Toxic Unit-Chronic-one hundred (100) divided by either the highest effluent concentration that causes no observable effect on the test organisms or the inhibition concentration (IC25) causing a twenty-five percent (25%) or more reduction in the reproduction or growth of the test organisms in a chronic toxicity test.

(B) For the purpose of this rule, the waters of the state are divided into the following categories:

1. The Missouri and Mississippi Rivers (section (2) of this rule);

2. Lakes and reservoirs, including natural lakes and any impoundments created by the construction of a dam across any waterway or watershed. An impoundment designed for or used as a disposal site for tailings or sediment from a mine or mill shall be considered a wastewater treatment device and not a lake or reservoir. Releases to lakes and reservoirs include discharges into streams one-half (1/2) stream mile (.80 km) before the stream enters the lake as measured to its conservation pool (section (3) of this rule);

3. A losing stream is a stream which distributes thirty percent (30%) or more of its flow through natural processes such as through permeable geologic materials into a bedrock aquifer within two (2) miles flow distance downstream of an existing or proposed discharge. Flow measurements to determine percentage of water loss must be corrected to approximate the seven- (7-) day Q10 stream flow. If a stream bed or drainage way has an intermittent flow or a flow insufficient to measure in accordance with this rule, it may be determined to be a losing stream on the basis of channel development, valley configuration, vegetation development, dye tracing studies, bedrock characteristics, geographical data, and other geological factors. Only discharges which in the opinion of the Missouri Department of Natural Resources (department) reach the losing section and which occur within two (2) miles upstream of the losing section of the stream shall be considered releases to a losing stream. Losing streams are defined in 10 CSR 20-2.010(40). Other streams may be determined to be losing by the department (section (4) of this rule);

4. Metropolitan no-discharge streams. These streams and the limitations on discharging to them are listed in Table F of 10 CSR 20-7.031 Water Quality Standards;

5. Special streams-Outstanding National Resource Waters and Outstanding State Resource Waters, as listed in Tables D and E of 10 CSR 20-7.031 (section (6) of this rule);

6. Subsurface waters in aquifers (section (7) of this rule); and

7. All other waters except as noted in paragraphs (1)(B)1.-6. of this rule (section (8) of this rule).

(C) Sections (2) though (8) of this rule establish requirements for discharges to the waters specified in these sections, and the requirements of section (9) of this rule apply to all discharges. The requirements of this rule do not apply to stormwater discharges; effluent limits for stormwater discharges are prescribed in 10 CSR 20-6.200 Storm Water Regulations.

(2) Effluent Limitations for the Missouri and Mississippi Rivers. In addition to the requirements of section (9) of this rule, the following limitations represent the maximum amount of pollutants which may be discharged from any point source, water contaminant source, or wastewater treatment facility.

(A) Discharges from wastewater treatment facilities which receive primarily domestic waste or from publicly-owned treatment works (POTWs) shall undergo treatment sufficient to conform to the following limitations:

1. Biochemical Oxygen Demand₅ (BOD₅) and Total Suspended Solids (TSS) equal to or less than a monthly average of thirty milligrams per liter (30 mg/L) and a weekly average of forty-five milligrams per liter (45 mg/L);

2. pH shall be maintained in the range from six to nine (6-9) standard units in accordance with 40 CFR 133.102 "Secondary Treatment Regulation" October 16, 1984, as published by the Office of the Federal Resister, National Archives and Records Administration, 700 Pennsylvania Avenue, Washington, DC 20408 which is hereby incorporated by reference and does not include later amendments or additions;

3. Exceptions to paragraphs (2)(A)1. and 2. of this rule are as follows:

A. If the facility is a wastewater lagoon, the TSS shall be equal to or less than a monthly average of eighty milligrams per liter (80 mg/L) and a weekly average of one hundred twenty milligrams per liter (120 mg/L) and the pH shall be maintained above six 6.0, and the BOD₅ shall be equal to or less than a monthly average of forty-five milligrams per liter (45 mg/L) and a weekly average of sixty-five milligrams per liter (65 mg/L);

B. If the facility is a trickling filter plant the BOD₅ and TSS shall be equal to or less than a monthly average of forty-five milligrams per liter (45 mg/L) and a weekly average of sixty-five milligrams per liter (65 mg/L);

C. Where the use of effluent limitations set forth in this section is known or expected to produce an effluent that will endanger or violate water quality, the department will set specific effluent limitations for individual dischargers to protect the water quality of the receiving streams;

D. The department may require more stringent limitations than authorized in paragraphs (2)(A)1. and 2. and subparagraphs (2)(A)3.A., B., and C. of this rule under the following conditions:

(I) If the facility is an existing facility, the department may set the BOD₅ and TSS limits based upon an analysis of the past performance, rounded up to the next five milligrams per liter (5 mg/L) range; and

(II) If the facility is a new facility, the department may set the BOD₅ and TSS limits based upon the design capabilities of the plant considering geographical and climatic conditions;

(a) A design capability study has been conducted for new lagoon systems. The study reflects that the effluent limitations should be BOD₅ equal to or less than a monthly average of forty-five milligrams per liter (45 mg/L) and a weekly average of sixty-five milligrams per liter (65 mg/L) and TSS equal to or less than a monthly average of seventy milligrams per liter (70 mg/L) and a weekly average of one hundred ten milligrams per liter (110 mg/L).

(b) A design capability study has been conducted for new trickling filter systems and the study reflects that the effluent limitations should be BOD₅ and TSS equal to or less than a monthly average of forty milligrams per liter (40 mg/L) and a weekly average of sixty milligrams per liter (60 mg/L); and

4. When the wastewater treatment process causes nitrification which affects the BOD₅ reading, the permittee can petition the department to substitute carbonaceous BOD₅ in lieu of regular BOD₅ testing. If the department concurs that nitrification is occurring, the department will set a carbonaceous BOD₅ at five milligrams per liter (5 mg/L) less than the regular BOD₅ in the operating permit.

(B) The suspended solids which are present in stream water and which are removed during treatment may be returned to the same body of water from which they were taken, along with any additional suspended solids resulting from the treatment of water to be used as public potable water or industrial purposes using essentially the same process as a public water treatment process. This includes the solids that are removed from potable waters that are withdrawn from wells located in the alluvial valley of the Missouri and Mississippi Rivers.

(C) Monitoring Requirements.

1. The department will develop a wastewater and sludge sampling program based on design flow and other site-specific factors. Sampling frequency shall not exceed once per day.

A. The department may establish less frequent sampling requirements for point sources that produce an effluent that does not exhibit high variability and consistently complies with the applicable effluent limit; and

B. Sludge sampling will be established in the permit.

2. Unless otherwise specified in the operating permit, sample types shall be:

A. Grab samples for lagoons and recirculating media beds;

B. Twenty-four- (24-) hour composite samples for mechanical plants; and

C. Sludge samples will be grab samples unless otherwise specified in the operating permit.

3. The monitoring frequency and sample types stated in subsection (2)(C) of this rule are minimum requirements.

(3) Effluent Limitations for the Lakes and Reservoirs.

(A) In addition to the requirements of section (9) of this rule, the following limitations represent the maximum amount of pollutants which may be discharged from any point source, water contaminant source, or wastewater treatment facility to a lake or reservoir designated in 10 CSR 20-7.031 as L2 and L3 which is publicly owned. Releases to lakes and reservoirs include discharges into streams one-half (1/2) stream mile (.80 km) before the stream enters the lake as measured to its conservation pool.

1. Discharges from wastewater treatment facilities which receive primarily domestic waste or from POTWs shall undergo treatment sufficient to conform to the following limitations:

A. BOD₅ and TSS equal to or less than a monthly average of twenty milligrams per liter (20 mg/L) and a weekly average of thirty milligrams per liter (30 mg/L);

B. pH shall be maintained in the range from six to nine (6- 9) standard units in accordance with 40 CFR 133.102 "Secondary Treatment Regulation" October 16, 1984, as published by the Office of the Federal Resister, National Archives and Records Administration, 700 Pennsylvania Avenue, Washington, DC 20408 which is hereby incorporated by reference and does not include later amendments or additions;

C. Where the use of effluent limitations set forth in section (3) of this rule are reasonably expected to exceed applicable water quality standards, the department may either-conduct waste load allocation studies in order to arrive at a limitation which protects the water quality of the state or set specific effluent limitations for individual dischargers to protect the water quality of the receiving streams; and

D. When the wastewater treatment process causes nitrification which affects the BOD₅ reading, the permittee can petition the department to substitute carbonaceous BOD₅ in lieu of regular BOD₅ testing. If the department concurs that nitrification is occurring, the department will set a carbonaceous BOD₅ at five milligrams per liter (5 mg/L) less than the regular BOD₅ in the operating permit.

(B) Monitoring Requirements.

1. The department will develop a wastewater and sludge sampling program based on design flow and other site-specific factors. Sampling frequency shall not exceed once per day.

B. Sludge sampling will be established in the permit.

2. Unless otherwise specified in the operating permit, sample types shall be:

A. Grab samples for lagoons and recirculating media beds;

B. Twenty-four- (24-) hour composite samples for mechanical plants; and

C. Sludge samples will be grab samples unless otherwise specified in the operating permit.

3. The monitoring frequency and sample types stated in paragraphs (3)(B)1. through 2. of this rule are minimum requirements.

(C) For lakes designated in 10 CSR 20-7.031 as L1, which are primarily used for public drinking water supplies, there will be no discharge into the watersheds above these lakes from domestic or industrial wastewater sources regulated by these rules.

1. Discharges from potable water treatment plants, such as filter wash, may be permitted.

2. Separate storm sewers will be permitted, but only for the transmission of storm water.

3. Discharges directly to L1 lakes for the purposes of water reuse and drought mitigation may be permitted if the discharge pollutant concentrations do not exceed the following limitations:

A. Ten milligrams per liter (10 mg/L) as a monthly average and fifteen milligrams per liter (15 mg/L) as a daily maximum of of BOD₅;

B. Fifteen milligrams per liter (15 mg/L) as a monthly average and twenty milligrams per liter (20 mg/L) as a daily maximum of TSS;

C. pH shall be maintained in the range from six to nine (6.0-9.0) standard units;

D. One hundred twenty-six (126) colony forming units per one hundred (100) ml (year round) of E. coli;

E. Eight milligrams per liter (8 mg/L) as an annual average of total nitrogen;

F. Five-tenths milligrams per liter (0.5 mg/L) as an annual average of total phosphorus; and

G. In addition to the requirements of section (9) of this rule, domestic and industrial point source discharges must ensure that toxic and bioaccumulative pollutants are not discharged at levels above the drinking water supply (DWS) criteria found in Table A1 of 10 CSR 20-7.031.

4. Discharges permitted prior to the effective date of this requirement may continue to discharge so long as the discharge remains in compliance with its operating permit.

(D) For lakes designated in 10 CSR 20-7.031 as L3 which are not publicly owned, the discharge limitations shall be those contained in section (8) of this rule.

(E) In addition to other requirements in this section, discharges to Lake Taneycomo and its tributaries between Table Rock Dam and Power Site Dam (and excluding the discharges from the dams) shall not exceed five tenths milligrams per liter (0.5 mg/L) of phosphorus as a monthly average. Discharges meeting both the following conditions shall be exempt from this requirement:

1. Those permitted prior to May 9, 1994; and

2. Those with design flows of less than twenty-two thousand five hundred (22,500) gpd.

The department may allow the construction and operation of interim facilities without phosphorus control provided their discharges are connected to regional treatment facilities with phosphorus control not later than three (3) years after authorization.

(F) In addition to other requirements in this section, discharges to Table Rock Lake watershed, defined as hydrologic units numbered 11010001 and 11010002, shall not exceed five-tenths milligrams per liter (0.5 mg/L) of phosphorus as a monthly average. Discharges meeting both of the following conditions are exempt from this requirement.

1. Those permitted prior to November 30, 1999; and

2. Those with design flows less than twenty-two thousand five hundred (22,500) gpd.

(G) Discharges in the White River basin and outside of the areas identified in (3)(E) and (F) of this section for phosphorus limitations shall be monitored for phosphorus discharges, and the frequency of monitoring shall be the same as that for BOD₅ and TSS, but not less than annually. The department may reduce the frequency of monitoring if the monitoring data is sufficient for water quality planning purposes.

(4) Losing Stream Determinations and Effluent Limitations for Losing Streams.

(A) The department may make losing stream determinations at any time, typically during review of the first application for discharge to a specific water or location within a watershed.

(B) The department shall process permit applications and other requests for approval in accordance with any existing losing stream determinations.

(C) For purposes of applying for any permit or other approval, any stream segment within two (2) miles upstream of a known losing stream segment is presumed to be also losing unless rebutted by a specific geologic evaluation that concludes the stream segment is not losing.

(D) Existing facilities operating under a state operating permit and new facilities being constructed under a construction permit within two (2) miles upstream of a known stream segment subsequently determined to be losing will be allowed to continue in operation at permitted or approved effluent limits for a period of time not to exceed the design life of the facility or twenty (20) years from the original construction completion, whichever is less, provided the facility is in compliance with its effluent limits and remains in compliance with those limits, and if neither of the following conditions is present:

1. The discharge from such a facility can be eliminated by connection to a locally available facility, in which case the fa- cility shall connect and eliminate its discharge within three (3) years of the losing stream determination. A local facility shall be considered available if that facility or an interceptor has capacity to accept the additional flow and is within two thousand (2,000) feet or a distance deemed feasible by the department; and

2. The discharge from such a facility is shown to cause pollution of groundwater, in which case the facility shall be upgraded to appropriate effluent standards within three (3) years.

(E) The department shall process any additional permits or approvals for increased treatment plant design capacity in accordance with the most recent losing stream determination. No additional permits or approvals for any facilities shall be construed as lengthening the time for compliance with losing stream effluent limitations as established in subsection (4)(D) of this rule.

(F) Prior to discharging to a losing stream, alternatives such as relocating the discharge to a gaining stream and connection to a regional wastewater treatment facility must be evaluated and determined to be unacceptable for environmental and/or economic reasons.

(G) In addition to the requirements of section (9) of this rule, each permit for a discharge from a wastewater treatment facility to a losing stream shall be written using the limitations contained in subsections (4) (G) and (H) of this rule in accordance with any applicable compliance schedule. Discharges from private wastewater treatment facilities which receive primarily domestic waste, industrial sources that treat influents containing significant amounts of organic loading, or POTWs permitted under this section shall undergo treatment sufficient to conform to the following limitations:

1. BOD₅ equal to or less than a monthly average of ten milligrams per liter (10 mg/L) and a weekly average of fifteen milligrams per liter (15 mg/L);

2. TSS equal to or less than a monthly average of fifteen milligrams per liter (15 mg/L) and a weekly average of twenty milligrams per liter (20 mg/L);

3. pH shall be maintained in the range from six to nine (6-9) standard units in accordance with 40 CFR 133.102 "Secondary Treatment Regulation," October 16, 1984, as published by the Office of the Federal Register, National Archives and Records Administration, 700 Pennsylvania Avenue, Washington, DC 20408, which is hereby incorporated by reference and does not include later amendments or additions;

4. All chlorinated effluent discharges to losing streams or within two (2) stream miles flow distance upstream of a losing stream shall also be dechlorinated prior to discharge;

5. When the wastewater treatment process causes nitrification which affects the BOD₅ reading, the permittee can petition the department to substitute carbonaceous BOD₅ in lieu of regular BOD₅ testing. If the department concurs that nitrification is occurring, the department will set a carbonaceous BOD₅ at five milligrams per liter (5 mg/L) less than the regular BOD₅ in the operating permit; and

6. For situations in which nitrates in a discharge can be reasonably expected to impact specific drinking water wells, the concentration of nitrates in the discharge shall be limited to an average monthly limit equal to or less than ten milligrams per liter (10 mg/L) as nitrogen and a maximum daily limit of twenty milligrams per liter (20 mg/L). Applicants may conduct a study in the same manner as the Missouri Risk-Based Corrective Action Technical Guidance, published in 2006, to determine if nitrate limits are necessary to protect groundwater. In such cases, applicants shall submit a study plan for approval prior to the study and submit all findings as part of their permit application.

(H) Monitoring Requirements.

1. The department will develop a wastewater and sludge sampling program based on design flow and other site-specific factors. Sampling frequency shall not exceed once per day.

B. Sludge samples will be established in the permit.

2. Unless otherwise specified in the operating permit, sample types shall be-

A. Grab samples for lagoons and recirculating media beds;

B. Twenty-four- (24-) hour composite samples for mechanical plants; and

C. Sludge samples shall be grab samples unless otherwise specified in the operating permit.

3. The monitoring frequency and sample types stated in paragraphs (4)(H)1. through 2. of this rule are minimum requirements.

(5) Effluent Limitations for Metropolitan No-Discharge Streams.

(A) Discharge to metropolitan no-discharge streams is prohibited, except as specifically permitted under the Water Quality Standards 10 CSR 20-7.031 and noncontaminated storm water flows.

(B) Monitoring Requirements.

1. The department will develop a wastewater and sludge sampling program based on design flow and other site-specific factors. Sampling frequency shall not exceed once per day.

B. Sludge sampling will be established in the permit.

2. Unless otherwise specified in the operating permits, sample types shall be:

A. Grab samples for lagoons and recirculating media beds;

B. Twenty-four- (24-) hour composite samples for mechanical plants; and

C. Sludge samples will be a grab sample unless otherwise specified in the operating permit.

3. The monitoring frequency and sample types stated in paragraphs (5)(B)1. through 2. of this rule are minimum requirements.

(6) Effluent Limitations for Special Streams.

(A) Limits for Outstanding National Resource Waters as listed in Table D of 10 CSR 20-7.031 and Drainages Thereto.

1. In addition to the requirements of section (9) of this rule, the following limitations represent the maximum amount of pollutants which may be discharged from any point source, water contaminant source, or wastewater treatment facility to waters included in this section.

2. Discharges from wastewater treatment facilities, which receive primarily domestic waste, or from POTWs are limited as follows:

A. New releases from any source are prohibited;

B. Discharges from sources that existed before June 29, 1974, or if additional stream segments are placed in this section, discharges that were permitted at the time of the designation will be allowed.

3. Industrial, agricultural, and other non-domestic contaminant sources, point sources, or wastewater treatment facilities which are not included under subparagraph (6)(A)2.B. of this rule shall not be allowed to discharge. All precipitation collected in the operational containment area or secondary containment area as well as process generated wastewater shall be stored and disposed of in a no-discharge manner.

4. Monitoring requirements.

A. The department will develop a wastewater and sludge sampling program based on design flow and other site-specific factors. Sampling frequency shall not exceed once per day.

(I) The department may establish less frequent sampling requirements for point sources that produce an effluent that does not exhibit high variability and consistently complies with the applicable effluent limit;

(II) Sludge sampling will be established in the permit.

B. Unless otherwise specified in the operating permit, sample types shall be:

(I) Grab samples for lagoons and recirculating media beds;

(II) Twenty-four- (24-) hour composite samples for mechanical plants; and

(III) Sludge samples shall be grab samples unless otherwise specified in the operating permit.

C. The monitoring frequency and sample types stated in sub- paragraphs (6)(A)4.A. through B. of this rule are minimum requirements.

(7) Effluent Limitations for Subsurface Waters.

(A) No person shall release any water into aquifers, store or dispose of water in a way which causes or permits it to enter aquifers either directly or indirectly unless it meets the requirements of section (9) of this rule and it meets the appropriate groundwater protection criteria set in 10 CSR 20-7.031, Table A at a point ten feet (10') under the release point, or other compliance point based on site specific considerations, except as provided in subsection (7)(D) of this rule. The permit writer shall review the complete application and other data to determine which parameter to include in the permit.

(B) No wastewater shall be introduced into sinkholes, caves, fissures, or other openings in the ground which do or are reasonably certain to drain into aquifers except as provided in section (4) of this rule.

(C) All abandoned wells and test holes shall be properly plugged or sealed to prevent pollution of subsurface waters, as per the requirements of the department.

(D) The effluent limitations specified in subsection (7)(A) of this rule shall not apply to facilities designed and constructed to meet department design criteria provided these designs have been reviewed and approved by the department. The department has the right to require monitoring, reporting, public notice, and other information as deemed appropriate. This exemption may be revoked by the department should any monitoring indicate an adverse effect on a beneficial water use or if the numeric criteria in the Water Quality Standards are being exceeded.

(E) Any person not included in subsection (7)(D) of this rule who releases, stores, or disposes of water in a manner which results in releases of water to an aquifer having concentrations in excess of one (1) or more parameter limitations provided in subsection (7)(A) of this rule may be allowed to resample for purposes of verification of the excess. At their discretion, persons may demonstrate, at the direction of the department, that the impact on the water quality in the aquifer is negligible on the beneficial uses. The demonstration shall consider, at a minimum, the following factors:

1. Site geology;

2. Site geohydrology;

3. Existing and potential water uses;

4. Existing surface water and groundwater quality;

5. Characteristics of wastes or wastewater contained in facilities; and

6. Other items as may be required by the department to assess the proposal.

A. Demonstrations conducted under 10 CSR 25-18.010 shall be reviewed by the department in accordance with such rules. If the demonstrations show that the impact on groundwater quality will not result in an unreasonable risk to human health or the environment, alternate effluent limitations will be established by the department.

B. All other demonstrations shall be reviewed by the department. If the demonstrations show that the impact on groundwater quality will not result in an unreasonable risk to human health or the environment, alternate effluent limitation(s) will be proposed by the department and presented to the Clean Water Commission for approval. The Clean Water Commission has the right to require monitoring, reporting, public notice, and other information as deemed appropriate in the approval of the alternate limitation for one (1) or more parameters from subsection (7)(A) of this rule. The Clean Water Commission may hold a public hearing to secure public comment prior to final action on an alternate limitation.

C. No alternate limitations will be granted which would impair beneficial uses of the aquifer or threaten human health or the environment.

D. Alternate limitations may be revoked by the department should any monitoring indicate an adverse effect on a beneficial water use or violations of the alternate limitation.

(8) Effluent Limitations for All Waters, Except Those in Paragraphs (1)(B)1.-6. of This Rule. In addition to the requirements of section (9) of this rule, the following limitations represent the maximum amount of pollutants which may be discharged from any point source, water contaminant source, or wastewater treatment facility.

(A) Discharges from wastewater treatment facilities which receive primarily domestic waste or POTWs shall undergo treatment sufficient to conform to the following limitations:

1. BOD₅ and TSS equal to or less than a monthly average of thirty milligrams per liter (30 mg/L) and a weekly average of forty-five milligrams per liter (45 mg/L);

3. The limitations of paragraphs (8)(A)1. and 2. of this rule will be effective unless an alternate limitation will not cause violations of the Water Quality Standards or impairment of the uses in the standards. When an Antidegradation Review has been completed for new or expanded discharges, the following alternate limitation may also be allowed:

A. If the facility is a wastewater lagoon, the TSS shall be equal to or less than a monthly average of eighty milligrams per liter (80 mg/L) and a weekly average of one hundred twenty milligrams per liter (120 mg/L) and the pH shall be maintained above six (6.0) and the BOD₅ shall be equal to or less than a monthly average of forty-five milligrams per liter (45 mg/L) and a weekly average of sixty-five milligrams per liter (65 mg/L);

B. If the facility is a trickling filter plant, the BOD₅ and TSS shall be equal to or less than a monthly average of forty-five milligrams per liter (45 mg/L) and a weekly average of sixty-five milligrams per liter (65 mg/L);

C. Where the use of effluent limitations set forth in section (8) of this rule is known or expected to produce an effluent that will endanger water quality, the department will set specific effluent limitations for individual dischargers to protect the water quality of the receiving streams; and

D. The department may require more stringent limitations than authorized in paragraphs (8)(A)1. and 2. and subparagraphs (8)(A)3.A., B., and C. of this rule under the following conditions:

(II) If the facility is a new facility the department may set the BOD₅ and TSS limits based upon the design capabilities of the plant considering geographical and climatic conditions:

(B) Monitoring Requirements.

1. The department will develop a wastewater and sludge sampling program based on design flow and other site-specific factors. Sampling frequency shall not exceed once per day.

B. Sludge sampling will be established in the permit.

2. Unless otherwise specified in the operating permit, sample types shall be:

A. Grab samples for lagoons and recirculating media beds;

B. Twenty-four- (24-) hour composite samples for mechanical plants; and

C. Sludge samples will be a grab sample unless otherwise specified in the operating permit.

3. The monitoring frequency and sample types stated in paragraphs (8)(B)1. through 2. of this rule are minimum requirements.

(9) General Conditions.

(A) Establishing Effluent Limitations. Unless a formal variance from water quality standards has been approved by the Clean Water Commission and the U.S. Environmental Protection Agency, operating permits issued under 10 CSR 20- 6.010(7) shall include, if applicable, the most protective limits set forth as follows:

1. Technology-based effluent limits and standards based on specific requirements under sections (2) through (8) of this rule;

2. Water quality-based effluent limits based on a waste load allocation in accordance with federal regulations (40 CFR 122.44(d)(1)), which would address pollutants that have a reasonable potential to cause or contribute to an excursion above Water Quality Standards established in 10 CSR 20-7.031.

A. Local effluent and receiving water data may be used to develop site-specific effluent limits provided the depart- ment determines that this data is representative and 10 CSR 20-7.031 provides for their development.

B. Water quality-based effluent limitations incorporating mixing zones and zones of initial dilution as provided for in 10 CSR 20-7.031(5)(A) 4.B. may be based on stream flows other than critical low-flow conditions, if the following conditions are met:

(I) The limits are protective of critical low-flow conditions, as well as higher flow conditions; and

(II) The permit shall require in-stream flow measurements and methods to determine compliance;

3. Effluent limit guidelines or standards that have been federally promulgated under Sections 301, 304, 306, 307, 318, and 405 of the Clean Water Act and case-by-case determinations of technology-based effluent limitations under section 402(a)(1) of the Clean Water Act;

4. Effluent limits for discharges subject to a total maximum daily load (TMDL) necessary to achieve water quality standards, including permit limits in lieu of a TMDL. Permit limitations consistent with the requirements and assumptions of an approved waste load allocation within a TMDL shall be placed in permits as needed. Permits may include schedules of compliance and, if developed, follow TMDL implementation plans, adaptive management approaches, or other flexibilities so long as they are allowed by federal regulation. The department may reopen existing permits to implement TMDL requirements;

5. Effluent limits that are developed through the antidegradation review process, provided there is reasonable potential to exceed these limits;

6. Effluent limits that are required as a result of legal agreements between dischargers and the department or the Clean Water Commission, or as otherwise required or allowed by law; and

7. Compliance with permit limits established in accordance with subsections (3)(E) and (3)(F) or paragraphs (9)(A)4. and 5. of this rule can be achieved though total phosphorus and total nitrogen nutrient credit trading conducted in accordance with subparagraph (9)(B)2.E.

(B) Bacteria and Statewide Nutrient Limits. Operating permits as required under 10 CSR 20-6.010(7) shall include, if applicable, the following bacteria and nutrient limits:

1. Bacteria. The following water quality Escherichia coli (E. coli) discharge limits apply:

A. Discharges to stream segments designated in Table H of 10 CSR 20-7.031 for whole body contact recreation and secondary contact recreation shall not exceed the water quality E. coli counts established in subsection (5)(C) of 10 CSR 20-7.031;

B. Discharges to lakes designated as whole body contact recreational or secondary contact recreational in Table G of 10 CSR 20-7.031 shall not exceed the water quality E. coli counts established in subsection (5)(C) of 10 CSR 20-7.031;

C. Discharges located within two (2) miles upstream of stream segments or lakes designated for whole body contact recreational or secondary contact recreational in Tables H and G of 10 CSR 20-7.031 shall not exceed the water quality E. coli counts established in subsection (5)(C) of 10 CSR 20-7.031 for the receiving stream segment or lake designated for those uses;

D. E. coli limits. During the recreation season, discharges to waters designated for whole body contact "A" as defined in part (1)(C)2.A.(I) of 10 CSR 20-7.031 shall be limited to one hundred twenty-six (126) colony forming units per one hundred (100) milliliters (ml) expressed as a monthly geometric mean for POTWs and non-POTWs. During the recreation season, discharges to waters designated for whole body contact "B" as defined in part (1)(C)2.A.(II) of 10 CSR 20-7.031 shall be limited to two hundred six (206) colony forming units per one hundred (100) ml expressed as a monthly geometric mean for POTWs and non-POTWs. During the recreation season, discharges to waters designated for secondary contact recreational as defined in subparagraph (1)(C)2.B. of 10 CSR 20-7.031 shall be limited to one thousand one hundred thirty-four (1,134) colony forming units per one hundred (100) ml expressed as a monthly geometric mean for POTWs and non-POTWs. For the entire calendar year, discharges to waters that are defined by paragraph (1)(B)3. of this rule as losing streams shall be limited to one hundred twenty-six (126) colony forming units per one hundred (100) ml expressed as a daily maximum;

E. Short-term E. coli limits. Short-term effluent limitations shall be expressed as a daily maximum for non-POTWs and as a weekly geometric mean for POTWs. Short-term effluent limitations for discharges to waters designated for whole body contact "A" and "B" as well as those designated for secondary contact recreation shall be derived by multiplying the monthly geometric mean effluent limitations identified in (9)(B)1.D. of this rule by a factor of five (5), except that alternative multipliers may be utilized to calculate shortterm E. coli limitations when proposed and incorporated into permits. At no time shall using alternative multipliers in short-term effluent limitations cause or contribute to an excursion of the in-stream water quality criteria;

F. As an alternative to the limits prescribed in subparagraphs (9)(B)1.A. through E. of this rule, the department may allow permit applicants to conduct a study to develop E. coli limits that reflect pathogen decay. Prior to conducting this study applicants shall submit a quality assurance project plan for approval prior to the study, and submit all findings as part of their permit application; and

G. Notwithstanding the bacteria limits prescribed in subparagraphs (9)(B)1.A. through F. of this rule, discharges to losing streams shall be considered in compliance so long as no more than ten (10) percent of samples exceed one hundred twenty-six (126) colony forming units per one hundred (100) ml daily maximum;

2. Nutrient reduction targets and trading. This rule establishes nutrient reduction targets implementing part of the Missouri Nutrient Loss Reduction Strategy to contribute to a statewide reduction in total phosphorus.

A. Total phosphorus. The following total phosphorus target reduction levels apply to all domestic point sources with a design flow of greater than or equal to 1,000,000 gallons per day (MGD) and all industrial facilities categorized as major that typically discharge phosphorus in their industrial wastewater, except for point sources subject to total phosphorus effluent limitations identified in subsections (3)(E) and (3)(F) or paragraphs (9)(A)4. and 5. of this rule or where a more stringent limit has been established in accordance with other provisions of this rule, and shall be implemented as follows:

(I) Total phosphorus target level of one milligrams per liter (1.0 mg/L), as an annual average; or

(II) Total phosphorus annual mass loading target level equal to one milligram per liter (1.0 mg/L) based on the design flow. Combined sewer systems may request alternative considerations or calculations, if approved in an operating permit; or

(III) An overall reduction of total phosphorus from influent to effluent by seventy-five percent (75%) based on a one- (1-) time calculation of two (2) years of representative monitoring or process influent and effluent data; or

(IV) An overall reduction of annual load of total phosphorus discharged by seventy-five percent (75%) based on a one- (1-) time calculation of adequately representative effluent data; and

(V) The assessment of compliance with these levels will be based on actual flows annually, but monthly monitoring and reporting of the rolling annual average will be conducted;

B. Total nitrogen. Reserved;

C. Total phosphorus and total nitrogen. Facilities that elect to implement treatment for total phosphorus and total nitrogen simultaneously shall establish a nitrogen target reduction level and may request alternative implementation dates in accordance with subparagraph (9) (B)2.D of this rule;

D. Total phosphorus target reduction levels established in subparagraph (9)(B)2.A. must be implemented no later than the dates below, unless the department approves alternative implementation dates, which must be established in an operating permit:

(I) By January 1, 2029, for domestic point sources with facility design flows greater than 15 MGD;

(II) By January 1, 2033, for domestic point sources with facility design flows greater than or equal to 1MGD but less than 15 MGD;

(III) By January 1, 2034, for industrial facilities;

(IV) Alternative implementation dates may be requested based on the following:

(a) Affordability analysis per section 644.145, RSMo;

(b) Integrated management plans;

(c) Expected regionalization plans;

(d) The cost of implementing the pollution control measures to comply would cause undue financial burden to the facility or its indirect dischargers;

(e) A department-approved Nutrient Reduction Master Plan that includes a facility assessment and plans to reduce both phosphorus and nitrogen; or

(f) Facilities included in an aggregate assessment or allocation for multiple point sources;

E. Nutrient trading and credit generation. Nutrient credits may be used to comply with the target reduction levels of subparagraph (9)(B)2.A. of this rule. Nutrient credits may be used to comply with nutrient limits established in accordance with subsections (3)(E) or (3)(F) or paragraph (9)(A)4. or (9)(A)5. of this rule. Nutrient credits may be generated-

(I) In accordance with a permittee's Nonpoint Source Credit Generation Plan or Point Source Trade Plan, approved by the department and incorporated into the operating permit;

(II) Through early compliance with the nutrient target reduction levels established with this paragraph. Facilities may track and trade nutrient reductions achieved prior to January 1, 2029, with department approval; or

(III) Through use of an approved aggregate assessment and allocation for multiple point sources.

(C) Schedules of Compliance.

1. Compliance with new or revised National Pollutant Discharge Elimination System (NPDES) or Missouri operating permit limitations shall be achieved and in accordance with the federal regulation 40 CFR Part 122.47 , "Schedules of Compliance," May 15, 2000, as published by the Office of the Federal Register, National Archives and Records Administration, Superintendent of Documents, Pittsburgh, PA 15250-7954, which is hereby incorporated by reference and does not include later amendments or additions.

2. A compliance schedule may be modified in accordance with the federal regulation 40 CFR 122.62 "Modification or revocation and reissuance of permits," November 20, 2008, as published by the Office of the Federal Resister, National Archives and Records Administration, 700 Pennsylvania Avenue, Washington, DC 20408 which is hereby incorporated by reference and does not include later amendments or additions.

(D) Monitoring, Analysis, and Reporting.

1. All construction and operating permit holders shall submit reports at intervals established by the permit or at any other reasonable intervals required by the department. The monitoring and analytical schedule shall be as established by the department in the operating permit.

2. The analytical and sampling methods used must conform to federal regulation 40 CFR Part 136.3 "Identification of test procedures," August 28, 2017, as published by the Office of the Federal Register, National Archives and Records Administration, 700 Pennsylvania Avenue, Washington, DC 20408, which is hereby incorporated by reference and does not include later amendments or additions.

3. Approval of alternative test procedures shall follow the criteria set forth in federal regulation 40 CFR 136.4 "Application for and approval of alternate test procedures for nationwide use," August 28, 2017, as published by the Office of the Federal Register, National Archives and Records Administration, Washington, DC 20408, or federal regulation 40 CFR 136.5 "Approval of alternate test procedures for limited use," August 28, 2017, as published by the Office of the Federal Register, National Archives and Records Administration, 700 Pennsylvania Avenue, Washington, DC 20408, which are incorporated by reference and do not include later amendments or additions.

4. Sampling and analysis by the department to determine violations of this regulation will be conducted in accordance with the methods listed in paragraph (9)(D)2. of this rule or any other approved by the department. Violations may also be determined by review of the permittee's self-monitoring reports.

5. If, for any reason, the permittee does not comply with or will be unable to comply with any discharge limitations or standards specified in the permit, the permittee shall provide the department with the following information, with the next discharge monitoring report as required under subsection (9) (D) of this rule:

A. A description of the discharge and cause of noncompliance;

B. The period of noncompliance, including exact dates and times and/or the anticipated time when the discharge will return to compliance; and

C. The steps being taken to reduce, eliminate, and prevent recurrence of the noncompliance.

6. In the case of any discharge subject to any applicable toxic pollutant effluent standard under Section 307(a) of the federal Clean Water Act, the information required by paragraph (9)(D)5. of this rule regarding a violation of this standard shall be provided within twenty-four (24) hours from the time the owner or operator of the water contaminant source, point source, or wastewater treatment facility becomes aware of the violation or potential violation. This information may be provided via an electronic web-based system developed by the department, provided it is available. If this information is provided orally, a written submission covering these points shall be provided within five (5) working days of the time the owner or operator of the water contaminant source, point source, or wastewater treatment facility becomes aware of the violation.

7. Bacteria monitoring for disinfection.

A. For systems that have a design capacity of greater than one hundred thousand (100,000) gpd, a minimum of one (1) sample shall be collected for E. coli analysis each calendar week during the recreational season from April 1 through October 31. Compliance with the E. coli water quality standard established in subsection (5)(C) of 10 CSR 20-7.031 shall be determined each calendar month by calculating the geometric mean of all of the samples collected each calendar month. Compliance with the short-term E. coli limits established in subparagraph (9)(B)1.E. of this rule shall also be determined.

B. For systems that discharge to stream segments that are defined by paragraph (1)(B)3. as losing streams and have a design capacity of greater than one hundred thousand (100,000) gpd, a minimum of one (1) sample shall be collected for E. coli analysis each calendar week all year. Compliance with the E. coli water quality standard established in subsection (5)(C) of 10 CSR 20-7.031 and with the short term E. coli limits established in subparagraph (9)(B)1.E. of this rule shall also be determined.

C. For systems that have a design capacity of one hundred thousand (100,000) gpd or less, the sampling frequency for E. coli analysis shall be in accordance with the wastewater and sludge sampling program based on the design flow which is dependent upon the receiving water category as listed in subsection (1)(B) of this rule. Compliance with the E. coli water quality standard established in subsection (5)(C) of 10 CSR 20-7.031 shall be determined each calendar month by calculating the geometric mean of all of the samples collected each calendar month. Compliance with the short-term E. coli limits established in subparagraph (9)(B)1.E. of this rule shall also be determined.

8. Statewide monitoring for nutrients. Point sources that have the design capacity of greater than one hundred thousand (100,000) gpd that typically discharge nitrogen and phosphorus shall collect and analyze influent and effluent samples for total phosphorus, ammonia, total kjeldahl nitrogen and nitrate plus nitrite utilizing methods outlined in paragraph (D)2. of this section using the following frequencies:

A. Quarterly for facilities with design capacities greater than one hundred thousand (100,000) gpd and less than 1,000,000 gpd for a period up to five (5) years. The department may require additional monitoring to ascertain a discharge's nutrient contribution and the efficacy of the treatment technology as it pertains to nutrient removal.

B. Monthly for facilities with design capacities greater than or equal to 1,000,000 gpd for a period up to five (5) years. The department may require additional monitoring to ascertain a discharge's nutrient contribution and the efficacy of the treatment technology as it pertains to nutrient removal.

C. The department may impose ongoing or more frequent monitoring in permits that impose effluent limits for total nitrogen or total phosphorus or in situations in which monitoring is appropriate to ensure compliance with water quality standards, specific lake limits, or nutrient reduction target levels specified under subsection (3)(E) and (F) and paragraph (9)(B)2. of this rule.

(E) Dilution Water. Dilution of treated wastewater with cooling water or other less contaminated water to lower the effluent concentration to limits required by an effluent regulation of the Clean Water Law shall not be an acceptable means of treatment.

(F) Compliance with New Source Performance Standards.

1. Except as provided in paragraph (9)(F)2. of this rule, any new water contaminant source, point source, or wastewater treatment facility on which construction commenced after October 18, 1972, or any new source, which meets the applicable promulgated new source performance standards before the commencement of discharge, shall not be subject to any more stringent new source performance standards or to any more stringent technology-based standards under subsection 301(b)(2) of the federal Clean Water Act for the shortest of the following periods:

A. Ten (10) years from the date that construction is completed;

B. Ten (10) years from the date the source begins to discharge process or other nonconstruction related wastewater; or

C. The period of depreciation or amortization of the facility for the purposes of section 167 or 169 (or both) of the Internal Revenue Code of 1954.

2. The protection from more stringent standards of performance afforded by paragraph (9)(F)1. of this rule does not apply to-

A. Additional or more stringent permit conditions which are not technology based, for example, conditions based on water quality standards or effluent standards or prohibitions under Section 307(a) of the federal Clean Water Act; and

B. Additional permit conditions controlling pollutants listed as toxic under Section 307(a) of the federal Clean Water Act or as hazardous substances under Section 311 of the federal Clean Water Act and which are not controlled by new source performance standards. This exclusion includes permit conditions controlling pollutants other than those identified as hazardous where control of those other pollutants has been specifically identified as the method to control the hazardous pollutant.

(G) Bypass. Bypass means the intentional diversion of waste streams from any portion of a treatment facility, except in the case of blending. Severe property damage means substantial physical damage to property, damage to the treatment facilities which causes them to become inoperable, or substantial and permanent loss of natural resources which can reasonably be expected to occur in the absence of a bypass. Severe property damage does not mean economic loss caused by delays in production. Blending is the practice of diverting wet-weather flows around any treatment unit and recombining those flows within the treatment facility, while providing primary and secondary or biological treatment up to the available capacity, consistent with all applicable effluent limits and conditions. Stipulations regarding bypass allowances, prohibitions and reporting requirements shall comply with federal regulation 40 CFR 122.41 "Conditions applicable to all permits (applicable to state programs, See section 123.25), October 22, 2015, as published by the Office of the Federal Register, National Archives and Records Administration, 700 Pennsylvania Avenue, Washington, DC 20408, which are incorporated by reference and do not include later amendments or additions.

(H) Sludge facilities shall meet the applicable control technology for sewage sludge treatment, use, and disposal as published by the E PA in 40 CFR 503 and applicable state standards and limitations published in 10 CSR 20 and 10 CSR 80. Where there are no standards available or applicable, or when more stringent standards are appropriate to protect human health and the environment, the department shall set specific limitations in permits on a case-by-case basis using best professional judgment.

(I) Industrial, agricultural, and other nondomestic water contaminant sources, point sources, or wastewater treatment facilities which are not included under subsections (2)(A) or (8)(A) of this rule-

1. These facilities shall meet the applicable control technology currently effective as published by the EPA in 40 CFR 405-471. Where there are no standards available or applicable, the department shall set specific parameter limitations using best professional judgment. The pH shall be maintained in the range from six to nine (6-9) standard units, except that discharges of uncontaminated cooling water and water treatment plant effluent may exceed nine (9) standard units, but may not exceed ten and one-half (10.5) standard units, if it can be demonstrated that the pH will not exceed nine (9) standard units beyond the regulatory mixing zone; and

2. All precipitation collected in the operational containment area or secondary containment area as well as process generated wastewater shall be stored and disposed of in a no-discharge manner or treated to meet the applicable control technology referenced in paragraph (9)(I)1. of this rule.

(J) Implementation Schedule for Protection of Whole Body Contact and Secondary Contact Recreation.

1. For discharges to water bodies designated for whole body contact and secondary contact recreational use prior to July 1, 2012, in 10 CSR 20-7.031, permits shall insure compliance with effluent limits to protect whole body contact and secondary contact recreation by no later than December 31, 2013, unless the permittee presents an evaluation sufficient to show that disinfection is not required to protect one (1) or both designated recreational uses, or a UAA demonstrates that one (1) or both designated recreational uses are not attainable in the classified waters receiving the effluent.

2. For discharges to water bodies designated for whole body contact and secondary contact recreational use after June 30, 2012, in 10 CSR 20-7.031, permits shall include schedules of compliance to meet bacteria limits in accordance with subsection (9)(C) of this rule.

(K) Temporary Suspension of Accountability for Bacteria Standards during Wet Weather. The accountability for bacteria standards may be temporarily suspended for specific discharges when conditions contained in paragraphs (9)(K)1. through 3. of this rule are met.

1. No existing recreational uses downstream of the discharge will be impacted during the period of suspension as confirmed through a water quality review for reasonable potential for downstream impacts and a UAA performed in accordance with the Missouri Recreational Use Attainability Analysis Protocol approved by the Missouri Clean Water Commission.

2. The period of suspension must be restricted to the defined wet weather event that corresponds to the period when recreational uses are unattainable. The period must be determinable at any time by the discharger and the general public (such as from stream depth or flow readings or other stream conditions on which publicly accessible records are kept).

3. The suspension shall be subject to public review and comment, Missouri Clean Water Commission approval, and EPA approval before becoming effective and shall be contained as a condition in a discharge permit or other written document developed through public participation.

(L) Whole Effluent Toxicity (WET) Test. The following are permit requirements for acute and chronic WET tests:

1. WET tests are to be conducted according to the methods prescribed in 40 CFR 136.3;

2. Test Types.

A. Acute WET tests shall be a multiple dilution series, static, non-renewal test to determine the degree at which acute forty-eight to ninety-six hour (48-96 hour) exposure to the effluent is acutely toxic to aquatic life expressed in species survival.

B. Chronic WET test shall be a multiple dilution series, static, renewal test to determine the degree at which chronic (sub lethal) exposure to the effluent is toxic to aquatic life or affects an alternative endpoint such as species reproduction and/or growth. Duration of chronic WET tests shall be established according to 40 CFR 136.3 Identification of test procedures, promulgated as of July 1, 2011, is hereby incorporated by reference in this rule, as published by the Office of the Federal Register, U.S. National Archives and Records, 700 Pennsylvania Avenue N W, Washington, DC 20408. This rule does not incorporate any subsequent amendments or additions;

3. Applicability. WET test type and frequency shall be determined and expressed in permits by the department. At permit issuance or reissuance, the department will use valid and representative data to establish on a case-by-case basis, whether an existing discharge causes, has the reasonable potential to cause, or contributes to an excursion from the narrative water quality criteria. Where the department concludes that a discharge has the reasonable potential to contribute to an excursion from the narrative water quality criteria, as established in 10 CSR 20- 7.031 the permit will include WET limits. If the department determines the facility has no reasonable potential to violate water quality standards, WET testing may be removed, or if more information is required, WET testing may be retained at a reduced frequency. WET test applicability for NPDES permits shall be fully addressed in the permit factsheet; and

4. Specifications.

A. A dilution series shall be established in the permit for WET test. The dilution series shall be a set of proportional effluent dilutions based on an Allowable Effluent Concentration (AEC).

B. All WET tests shall be performed with Pimephales promelas (a fathead minnow) and Ceriodaphnia dubia (a water flea), except facilities which discharge to receiving streams designated as cold-water fisheries. Facilities which discharge to receiving streams designated as cold-water fisheries may be required to perform WET tests using Oncorhynchus mykiss (rainbow trout) instead of the fathead minnow. Other test species for which test methods are provided in 40 CFR 136.3 may be approved by the department on a case-by-case basis provided the species are appropriately sensitive and representative. Alternative species (not included in 40 CFR 136.3) shall be approved in accordance with the procedures in 40 CFR 136.4. Application for alternate test procedures, promulgated as of August 28, 2017, is hereby incorporated by reference in this rule, as published by the Office of the Federal Register, U.S. National Archives and Records, 700 Pennsylvania Avenue N W, Washington, DC 20408. This rule does not incorporate any subsequent amendments or additions.

C. A Toxic Unit (TU) water quality based limit shall be established in the permit for WET test where the department concludes that a discharge has the reasonable potential to cause or contribute to an excursion from the narrative water quality criteria as established in 10 CSR 20-7.031(4)(D). The TU limit shall be determined in accordance with 40 CFR 122.44(d)(1)(v) and utilizing the methods established in Technical Support Document For Water Quality-based Toxics Control (March 1991, EPA, EPA/505/2-90001) and documented in the factsheet. Exceedance of a TU limit shall be a WET test failure.

D. Upon completion of a WET test the lab report and department form as referenced in the permit shall be submitted by the permittee to the department within the timeframe established by the permit.

(10) Control of Combined Sewer Overflows (CSOs). The permitting and control of CSOs shall conform to EPA's CSO Control Policy, E PA Number 830/B-94-001 (published by E PA April 19, 1994, at 59 Fed. Reg. 18688) as referenced by Section 402 (q) of the Clean Water Act, 33 USC 1342(q). The CSO Control Policy is hereby incorporated by reference, without any later amendments or additions. This document is available by writing to U.S. Environmental Protection Agency, Office of Water Resource Center, Mail Code RC-4100T, 1200 Pennsylvania Avenue N W, Washington, DC 20460 or upon request from the Department of Natural Resources, Water Protection Program, Water Pollution Control Branch, PO Box 176, Jefferson City, MO 65102-0176. Effluent monitoring commitments for CSOs shall be addressed in the long term control plans required under EPA's CSO Control Policy.

10 CSR 20-7.015

AUTHORITY: section 644.026, RSMo Supp. 2013.* Original rule filed June 6, 1974, effective 6/16/1974. Amended: Filed April 1, 1975, effective April 11 , 1975. Rescinded: Filed Oct. 16, 1979, effective July 11 , 1980. Readopted: Filed Feb. 4, 1980, effective July 11 , 1980. Rescinded and read-opted: Filed Nov. 10, 1982, effective 5/12/1983. Amended: Filed Sept. 11 , 1984, effective 3/12/1985. Amended: Filed July 25, 1985, effective 12/26/1985. Amended: Filed Feb. 1, 1988, effective 6/13/1988. Amended: Filed Sept. 13, 1988, effective 2/14/1989. Amended: Filed July 15, 1991, effective 1/13/1992. Amended: Filed Sept. 2, 1993, effective 5/9/1994. Amended: Filed March 1, 1999, effective 11/30/1999. Amended: Filed Dec. 30, 1999, effective 9/30/2000. Amended: Filed March 31, 2005, effective 12/31/2005. Amended: Filed Sept. 28, 2009, effective 6/30/2010. Amended: Filed May 15, 2013, effective 2/28/2014.

Amended by Missouri Register January 2, 2019/Volume 44, Number 1, effective 2/28/2019

Amended by Missouri Register September 15, 2023/Volume 48, Number 18, effective 10/31/2023

*Original authority: 644.026, RSMo 1972, amended 1973, 1987, 1993, 1995, 2000, 2012.