Title 40 · EPA
Grain Mills Point Source Category
40 C.F.R. Part 406 · Updated July 1, 2025
§ 406.10 — Applicability; description of the corn wet milling subcategory.
The provisions of this subpart are applicable to discharges resulting from the process in which shelled corn is steeped in a dilute solution of sulfurous acid and then processed by wet means into such products as animal feed, regular and modified starches, corn oil, corn syrup, and dextrose.
§ 406.11 — Specialized definitions.
For the purpose of this subpart:
(a) Except as provided below, the general definitions, abbreviations and methods of analysis set forth in 40 CFR part 401 shall apply to this subpart.
(b) The term corn shall mean the shelled corn delivered to a plant before processing.
(c) The term standard bushel shall mean a bushel of shelled corn weighing 56 pounds.
(d) The abbreviation MSBu shall mean 1000 standard bushels.
§ 406.12 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.
(a) Except as provided in §§ 125.30 through 125.32, and subject to the provisions in paragraph (b) of this section, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT):
(b) The limitations given in paragraph (a) of this section for BOD5 and TSS are derived for a point source producing products standards to the corn wet milling industry. For those plants producing modified starches at a rate of at least 15 percent by dry-basis weight of total sweetener and starch products per month for 12 consecutive months, the following limitations should be used to derive an additive adjustment to the discharge allowed by paragraph (a) of this section:
§ 406.13 — [Reserved]
§ 406.14 — Pretreatment standards for existing sources.
Any existing source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403. In addition, the following pretreatment standard establishes the quantity or quality of pollutants or pollutant properties controlled by this section which may be discharged to a publicly owned treatment works by a point source subject to the provisions of this subpart.
§ 406.15 — Standards of performance for new sources.
The following standards of performance establish the quantity or quality of pollutants or pollutant properties, controlled by this section, which may be discharged by a new source subject to the provisions of this subpart:
§ 406.16 — Pretreatment standards for new sources.
Any new source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403. In addition, the provisions set forth in paragraph (a) of this section apply, as well as the following pretreatment standard which establishes the quantity or quality of pollutants or pollutant properties controlled by this section which may be discharged to publicly owned treatment works by a new source subject to the provisions of this subpart.
(a) Process waste water shall not be discharged to a POTW at a flow rate or pollutant mass loading rate which is excessive over any time period during the peak load at a POTW. Excessive discharges are defined as those in which the flow of BOD5 or total suspended solids (TSS) exceed the respective values of P from the following formula:
Calculations are to be based on dry weather conditions.
§ 406.17 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology.
The following limitations establish the quantity or quality of pollutants or pollutant properties, controlled by this section, which may be discharged by a point source subject to the provisions of this subpart after application of the best conventional pollutant control technology.
(a) Subject to the provisions in paragraph (b) of this section, the following limitations establish the quantity or quality of pollutants or pollutant properties, controlled by this section, which may be discharged by a point source subject to the provisions of this subpart after application of the best available technology economically achievable:
(b) The limitations given in paragraph (a) of this section for BOD5 and TSS are derived for a point source producing products standard to the corn wet milling industry. For those plants producing modified starches at a rate of at least 15 percent by dry-basis weight of total sweetener and starch products per month for 12 consecutive months, the following limitations should be used to derive an additive adjustment to the discharge allowed by paragraph (a) of this section:
§ 406.20 — Applicability; description of the corn dry milling subcategory.
(a) The provisions of this subpart are applicable to discharges resulting from the process in which shelled corn is washed and subsequently milled by dry processes into such products as corn meal, grits, flour, oil, and animal feed.
(b) The provisions of this subpart do not apply to discharges from subsequent manufacturing operations to produce expanded or extruded feed or feed products.
§ 406.21 — Specialized definitions.
For the purpose of this subpart:
(a) Except as provided below, the general definitions, abbreviations and methods of analysis set forth in part 401 of this chapter shall apply to this subpart.
(b) The term corn shall mean the shelled corn delivered to a plant before processing.
(c) The term standard bushel shall mean a bushel of shelled corn weighing 56 pounds.
(d) The abbreviation MSBu shall mean 1000 standard bushels.
§ 406.22 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT):
§ 406.23 — [Reserved]
§ 406.24 — Pretreatment standards for existing sources.
Any existing source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403. In addition, the following pretreatment standard establishes the quantity or quality of pollutants or pollutant properties controlled by this section which may be discharged to a publicly owned treatment works by a point source subject to the provisions of this subpart.
§ 406.25 — Standards of performance for new sources.
The following standards of performance establish the quantity or quality of pollutants or pollutant properties, controlled by this section, which may be discharged by a new source subject to the provisions of this part:
§ 406.26 — Pretreatment standards for new sources.
Any new source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403.
§ 406.27 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT).
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT): The limitations shall be the same as those specified for conventional pollutants (which are defined in § 401.16) in § 406.22 of this subpart for the best practicable control technology currently available (BPT).
§ 406.30 — Applicability; description of the normal wheat flour milling subcategory.
The provisions of this subpart are applicable to discharges resulting from the processes in which wheat and other grains are milled by dry processes into flour and millfeed.
§ 406.31 — Specialized definitions.
For the purpose of this subpart:
(a) Except as provided below, the general definitions, abbreviations and methods of analysis set forth in part 401 of this chapter shall apply to this subpart.
§ 406.32 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT): There shall be no discharge of process waste water pollutants to navigable waters.
§ 406.33 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best available technology economically achievable.
The following limitations establish the quantity or quality of pollutants or pollutant properties which may be discharged by a point source subject to the provisions of this subpart after application of the best available technology economically achievable: there shall be no discharge of process waste water pollutants to navigable waters.
§ 406.34 — Pretreatment standards for existing sources.
Any existing source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403. In addition, the following pretreatment standard establishes the quantity or quality of pollutants or pollutant properties controlled by this section which may be discharged to a publicly owned treatment works by a point source subject to the provisions of this subpart.
§ 406.35 — Standards of performance for new sources.
The following standards of performance establish the quantity or quality of pollutants or pollutant properties which may be discharged by a new source subject to the provisions of this subpart: There shall be no discharge of process waste water pollutants to navigable waters.
§ 406.36 — Pretreatment standards for new sources.
Any new source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403.
§ 406.37 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT).
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT): The limitations shall be the same as those specified for conventional pollutants (which are defined in § 401.16) in § 406.32 of this subpart for the best practicable control technology currently available (BPT).
§ 406.40 — Applicability; description of the bulgur wheat flour milling subcategory.
The provisions of this subpart are applicable to discharges resulting from the process in which wheat is parboiled, dried, and partially debranned in the production of bulgur.
§ 406.41 — Specialized definitions.
For the purpose of the subpart:
(a) Except as provided below, the general definitions, abbreviations and methods of analysis set forth in part 401 of this chapter shall apply to this subpart.
(b) The term wheat shall mean wheat delivered to a plant before processing.
(c) The term standard bushel shall mean a bushel of wheat weighing 60 pounds.
(d) The abbreviation MSBu shall mean 1,000 standard bushels.
§ 406.42 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT):
§ 406.43 — [Reserved]
§ 406.44 — Pretreatment standards for existing sources.
Any existing source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403. In addition, the following pretreatment standard establishes the quantity or quality of pollutants or pollutant properties controlled by this section which may be discharged to a publicly owned treatment works by a point source subject to the provisions of this subpart.
§ 406.45 — Standards of performance for new sources.
The following standards of performance establish the quantity or quality of pollutants or pollutant properties, controlled by this section, which may be discharged by a new source subject to the provisions of this subpart:
§ 406.46 — Pretreatment standards for new sources.
Any new source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403.
§ 406.47 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT).
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT): The limitations shall be the same as those specified for conventional pollutants (which are defined in § 401.16) in § 406.42 of this subpart for the best practicable control technology currently available (BPT).
§ 406.50 — Applicability; description of the normal rice milling subcategory.
The provisions of this subpart are applicable to discharges resulting from the process in which rice is cleaned and milled by dry processes.
§ 406.51 — Specialized definitions.
For the purpose of this subpart:
(a) Except as provided below, the general definitions, abbreviations and methods of analysis set forth in part 401 of this chapter shall apply to this subpart.
§ 406.52 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT): There shall be no discharge of process waste water pollutants to navigable waters.
§ 406.53 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best available technology economically achievable.
The following limitations establish the quantity or quality of pollutants or pollutant properties which may be discharged by a point source subject to the provisions of this subpart after application of the best available technology economically achievable: there shall be no discharge of process waste water pollutants to navigable waters.
§ 406.54 — Pretreatment standards for existing sources.
Any existing source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403. In addition, the following pretreatment standard establishes the quantity or quality of pollutants or pollutant properties controlled by this section which may be discharged to a publicly owned treatment works by a point source subject to the provisions of this subpart.
§ 406.55 — Standards of performance for new sources.
The following standards of performance establish the quantity or quality of pollutants or pollutant properties which may be discharged by a new source subject to the provisions of this subpart: There shall be no discharge of process waste water pollutants to navigable waters.
§ 406.56 — Pretreatment standards for new sources.
Any new source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403.
§ 406.57 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT).
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT): The limitations shall be the same as those specified for conventional pollutants (which are defined in § 401.16) in § 406.52 of this subpart for the best practicable control technology currently available (BPT).
§ 406.60 — Applicability; description of the parboiled rice processing subcategory.
The provisions of this subpart are applicable to discharges resulting from the process in which rice is cleaned, cooked and dried before being milled.
§ 406.61 — Specialized definitions.
For the purpose of this subpart:
(a) Except as provided below, the general definitions, abbreviations and methods of analysis set forth in part 401 of this chapter shall apply to this subpart.
(b) The term “rice” shall mean rice delivered to a plant before processing.
(c) The abbreviation “cwt” shall mean hundred weight.
§ 406.62 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT):
§ 406.63 — [Reserved]
§ 406.64 — Pretreatment standards for existing sources.
Any existing source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403. In addition, the following pretreatment standard establishes the quantity or quality of pollutants or pollutant properties controlled by this section which may be discharged to a publicly owned treatment works by a point source subject to the provisions of this subpart.
§ 406.65 — Standards of performance for new sources.
The following standards of performance establish the quantity or quality of pollutants or pollutant properties, controlled by this section, which may be discharged by a new source subject to the provisions of this subpart:
§ 406.66 — Pretreatment standards for new sources.
Any new source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403.
§ 406.67 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT).
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT): The limitations shall be the same as those specified for conventional pollutants (which are defined in § 401.16) in § 406.62 of this subpart for the best practicable control technology currently available (BPT).
§ 406.70 — Applicability; description of the animal feed subcategory.
The provisions of this subpart are applicable to discharges resulting from the manufacturing of animal feeds (formula feed concentrate) using primarily grain and grain by-products which may be supplemented by proteins, pharmaceuticals, vitamins or mineral additives.
§ 406.71 — Specialized definitions.
For the purpose of this subpart: The general definitions, abbreviations and methods of analysis set forth in 40 CFR part 401 shall apply to this subpart.
§ 406.72 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT): There shall be no discharge of process waste water pollutants to navigable waters.
§ 406.73 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best available technology economically achievable.
The following limitations establish the quantity or quality of pollutants or pollutant properties, which may be discharged by a point source subject to the provisions of this subpart after application of the best available technology economically achievable: There shall be no discharge of process waste water pollutants to navigable waters.
§ 406.74 — [Reserved]
§ 406.75 — Standards of performance for new sources.
The following standards of performance establish the quantity or quality of pollutants or pollutant properties which may be discharged by a new source subject to the provisions of this subpart: There shall be no discharge of process waste water pollutants to navigable waters.
§ 406.76 — Pretreatment standards for new sources.
Any new source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403. In addition, the following pretreatment standard establishes the quantity or quality of pollutants or pollutant properties, controlled by this section, which may be discharged to a publicly owned treatment works by a new point source subject to the provisions of this subpart.
§ 406.77 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT).
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT): The limitations shall be the same as those specified for conventional pollutants (which are defined in § 401.16) in § 406.72 of this subpart for the best practicable control technology currently available (BPT).
§ 406.80 — Applicability; description of the hot cereal subcategory.
The provisions of this subpart are applicable to discharges resulting from the production of various breakfast cereals from grains, principally wheat and oats, requiring cooking prior to normal human consumption.
§ 406.81 — Specialized definitions.
For the purpose of this subpart:
(a) The general definitions, abbreviations and methods of analysis set forth in 40 CFR part 401 shall apply to this subpart.
(b) The term cereal shall mean breakfast cereal.
§ 406.82 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT): There shall be no discharge of process waste water pollutants to navigable waters.
§ 406.83 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best available technology economically achievable.
The following limitations establish the quantity or quality of pollutants or pollutant properties, which may be discharged by a point source subject to the provisions of this subpart after application of the best available technology economically achievable: There shall be no discharge of process waste water pollutants to navigable waters.
§ 406.84 — [Reserved]
§ 406.85 — Standards of performance for new sources.
The following standards of performance establish the quantity or quality of pollutants or pollutant properties, which may be discharged by a new source subject to the provisions of this subpart: There shall be no discharge of process waste water pollutants to navigable waters.
§ 406.86 — Pretreatment standards for new sources.
Any new source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403. In addition, the following pretreatment standard establishes the quantity or quality of pollutants or pollutant properties, controlled by this section, which may be discharged to a publicly owned treatment works by a new point source subject to the provisions of this subpart.
§ 406.87 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT).
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT): The limitations shall be the same as those specified for conventional pollutants (which are defined in § 401.16) in § 406.82 of this subpart for the best practicable control technology currently available (BPT).
§ 406.90 — Applicability; description of the ready-to-eat cereal subcategory.
The provisions of this subpart are applicable to discharges resulting from the processing of various grains and other materials (whole grain wheat, rice, corn grits, oat flour, sugar, and minor ingredients) to produce various breakfast cereals normally available for human consumption without cooking.
§ 406.91 — Specialized definitions.
For the purpose of this subpart:
(a) The general definitions, abbreviations and methods of analysis set forth in 40 CFR part 401 shall apply to this subpart.
(b) The term cereal shall mean breakfast cereal.
§ 406.92 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT):
§ 406.93-406.94 — 406.93-406.94 [Reserved]
§ 406.95 — Standards of performance for new sources.
The following standards of performance establish the quantity or quality of pollutants or pollutant properties, controlled by this section, which may be discharged by a new source subject to the provisions of this subpart:
§ 406.96 — Pretreatment standards for new sources.
Any new source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403. In addition, the following pretreatment standard establishes the quantity or quality of pollutants or pollutant properties, controlled by this section, which may be discharged to a publicly owned treatment works by a new point source subject to the provisions of this subpart.
§ 406.97 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT).
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT): The limitations shall be the same as those specified for conventional pollutants (which are defined in § 401.16) in § 406.92 of this subpart for the best practicable control technology currently available (BPT).
§ 406.100 — Applicability; description of the wheat starch and gluten subcategory.
The provisions of this subpart are applicable to discharges resulting from those industrial operations utilizing wheat flour as a raw material for production of wheat starch and gluten (protein) components through conventional processes of physical separation and subsequent refinement.
§ 406.101 — Specialized definitions.
For the purpose of this subpart: The general definitions, abbreviations and methods of analysis set forth in 40 CFR part 401 shall apply to this subpart.
§ 406.102 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available.
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable control technology currently available (BPT):
§ 406.103-406.104 — 406.103-406.104 [Reserved]
§ 406.105 — Standards of performance for new sources.
The following standards of performance establish the quantity or quality of pollutants or pollutant properties, controlled by this section, which may be discharged by a new source subject to the provisions of this subpart:
§ 406.106 — Pretreatment standards for new sources.
Any new source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403. In addition, the following pretreatment standard establishes the quantity or quality of pollutants or pollutant properties, controlled by this section, which may be discharged to a publicly owned treatment works by a new point source subject to the provisions of this subpart.
§ 406.107 — Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT).
Except as provided in §§ 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best conventional pollutant control technology (BCT): The limitations shall be the same as those specified for conventional pollutants (which are defined in § 401.16) in § 406.102 of this subpart for the best practicable control technology currently available (BPT).