A. Prohibited Discharge Standards:
1. General Prohibitions: No user shall introduce or cause to be introduced into the POTW any pollutant or wastewater which causes pass through or interference. These general prohibitions apply to all users of the POTW whether or not they are subject to categorical pretreatment standards or any other National, State, or local pretreatment standards or requirements.
2. Specific Prohibitions: No user shall introduce or cause to be introduced into the POTW the following pollutants, substances, or wastewater:
a. Pollutants which create a fire or explosive hazard in the POTW, including, but not limited to, wastestreams with a closed-cup flashpoint of less than one hundred forty degrees Fahrenheit (140°F) (60°C) using the test methods specified in 40 CFR 261.21;
b. Wastewater having a pH less than 6.5 or more than 9.0, or otherwise causing corrosive structural damage to the POTW or equipment;
c. Solid or viscous substances in amounts which will cause obstruction of the flow in the POTW resulting in Interference but in no case solids greater than one half inch (1/2") in any dimension;
d. Pollutants, including oxygen-demanding pollutants (BOD, etc.), released in a discharge at a flow rate and/or pollutant concentration which, either singly or by interaction with other pollutants, will cause Interference with the POTW;
e. Wastewater having a temperature which will inhibit biological activity in the treatment plant resulting in interference, but in no case wastewater which causes the temperature at the introduction into the treatment plant to exceed one hundred four degrees Fahrenheit (104°F) (40°C);
f. Petroleum oil, nonbiodegradable cutting oil, or products of mineral oil origin, in amounts that will cause interference or pass through;
g. Pollutants which result in the presence of toxic gases, vapors, or fumes within the POTW in a quantity that may cause acute worker health and safety problems;
h. Trucked or hauled pollutants, except at discharge points designated by the Pretreatment Coordinator in accordance with subsection 8-4-3D of this chapter;
i. Noxious or malodorous liquids, gases, solids, or other wastewater which, either singly or by interaction with other wastes, are sufficient to create a public nuisance or a hazard to life, or to prevent entry into the sewers for maintenance or repair;
j. Wastewater which imparts color which cannot be removed by the treatment process, such as, but not limited to, dye wastes and vegetable tanning solutions, which consequently imparts color to the treatment plant's effluent, thereby violating the City's IPDES permit;
k. Wastewater containing any radioactive wastes or isotopes except as specifically approved in writing by the Supervisor in compliance with applicable state or federal regulations;
l. Storm water, surface water, ground water, artesian well water, roof runoff, subsurface drainage, swimming pool drainage, condensate, deionized water, noncontact cooling water, and unpolluted wastewater, unless specifically authorized by the Pretreatment Coordinator;
m. Sludges, screenings, or other residues from the pretreatment of industrial wastes or from industrial processes;
n. Medical wastes, except as specifically authorized by the Pretreatment Coordinator in an Industrial Wastewater Discharge Permit;
o. Wastewater causing, alone or in conjunction with other sources, the WWTP's effluent to fail toxicity test;
p. Detergents, surface-active agents, or other substances which may cause excessive foaming in the POTW;
q. Any liquid, solids, or gases which by reason of their nature or quantity are, or may be, sufficient either alone or by interaction with other substances to cause fire or explosion or be injurious in any other way to the POTW or to the operation of the POTW. At no time, shall two (2) successive readings on an explosion meter, at the point of discharge into the system (or at any point in the system), be more than five percent (5%) nor any single reading over ten percent (10%) of the lower explosive limit (LEL) of the meter;
r. Grease, garbage other than ground garbage, animal guts or tissues, paunch manure, bones, hair, hides or fleshing's, entrails, whole blood, feathers, ashes, cinders, sand, spent lime, stone or marble dusts, metal, glass, straw, shavings, grass clippings, rags, spent grains, spent hops, waste paper, wood, plastics, gas, tar asphalt residues, residues from refining or processing of fuel or lubricating oil, mud, or glass grinding or polishing wastes;
s. Any substance which will cause the POTW to violate its IPDES and/or other disposal system permits.
t. Any wastewater, which in the opinion of the WWTP Superintendent or Pretreatment Coordinator can cause harm either to the POTW, have an adverse effect on the receiving stream, or can otherwise endanger life, limb, public property or constitute a nuisance, unless allowed under special agreement by the Pretreatment Coordinator, except that no special waiver shall be given from categorical pretreatment standards;
u. The contents of any settling tank or other vessel owned or used by any person in the business of collecting or pumping sewage, effluent or septage;
v. Any hazardous waste as prohibited or regulated by the State of Idaho or in EPA Rules 40 CFR Part 261;
w. Persistent pesticides and/or pesticides regulated by the Federal Insecticide Fungicide Rodenticide Act (FIFRA). Pollutants, substances or wastewater prohibited by this section shall not be processed or stored in such a manner that they could be discharged to the POTW;
x. Formaldehyde;
y. Industrial chemicals in concentrations that will cause interference or pass through.
3. Pollutants, substances, or wastewater prohibited by this section shall not be processed or stored in such a manner that they could be discharged to the POTW.
B. National Categorical Pretreatment Standards: Users must comply with the categorical pretreatment standards found at 40 CFR chapter I, subchapter N, parts 405-471.
1. Where a categorical pretreatment standard is expressed only in terms of either the mass or the concentration of a pollutant in wastewater, the Pretreatment Coordinator may impose equivalent concentration or mass limits in accordance with subsection 8-4-2B4 and 5 (40 CFR 403.6(c)).
2. When the limits in a categorical pretreatment standard are expressed only in terms of mass of pollutant per unit of production, the Pretreatment Coordinator may convert the limits to equivalent limitations expressed either as mass of pollutant discharged per day or effluent concentration for purposes of calculating effluent limitations applicable to individual industrial users (40 CFR 403.6(c)(2)).
3. When wastewater subject to a categorical pretreatment standard is mixed with wastewater not regulated by the same Standard, the Pretreatment Coordinator shall impose an alternate limit in accordance with 40 CFR 403.6(e).
4. When a categorical pretreatment standard is expressed only in terms of pollutant concentrations, an industrial user may request that the City convert the limits to equivalent mass limits. The determination to convert concentration limits to mass limits is within the discretion of the Pretreatment Coordinator. The City may establish equivalent mass limits only if the industrial user meets all the conditions set forth in subsection 8-4-2B4a(1) through (5) below.
a. To be eligible for equivalent mass limits, the industrial user must:
(1) Employ, or demonstrate that it will employ, water conservation methods and technologies that substantially reduce water use during the term of its industrial wastewater discharge permit;
(2) Currently use control and treatment technologies adequate to achieve compliance with the applicable categorical pretreatment standard, and not have used dilution as a substitute for treatment;
(3) Provide sufficient information to establish the facility's actual average daily flow rate for all wastestreams, based on data from a continuous effluent flow monitoring device, as well as the facility's long-term average production rate. Both the actual average daily flow rate and the long-term average production rate must be representative of current operating conditions;
(4) Not have daily flow rates, production levels, or pollutant levels that vary so significantly that equivalent mass limits are not appropriate to control the discharge; and
(5) Have consistently complied with all applicable categorical pretreatment standards during the period prior to the industrial user's request for equivalent mass limits.
b. An industrial user subject to equivalent mass limits must:
(1) Maintain and effectively operate control and treatment technologies adequate to achieve compliance with the equivalent mass limits;
(2) Continue to record the facility's flow rates through the use of a continuous effluent flow monitoring device;
(3) Continue to record the facility's production rates and notify the Pretreatment Coordinator whenever production rates are expected to vary by more than twenty percent (20%) from its baseline production rates determined in subsection B4a(3). Upon notification of a revised production rate, the Pretreatment Coordinator will reassess the equivalent mass limit and revise the limit as necessary to reflect changed conditions at the facility; and
(4) Continue to employ the same or comparable water conservation methods and technologies as those implemented pursuant to subsection B4a(1) of this section so long as it discharges under an equivalent mass limit.
c. When developing equivalent mass limits, the Pretreatment Coordinator:
(1) Will calculate the equivalent mass limit by multiplying the actual average daily flow rate of the regulated process(es) of the industrial user by the concentration-based daily maximum and monthly average standard for the applicable categorical pretreatment standard and the appropriate unit conversion factor;
(2) Upon notification of a revised production rate, will reassess the equivalent mass limit and recalculate the limit as necessary to reflect changed conditions at the facility; and
(3) May retain the same equivalent mass limit in subsequent industrial wastewater discharge permit terms if the industrial user's actual average daily flow rate was reduced solely as a result of the implementation of water conservation methods and technologies, and the actual average daily flow rates used in the original calculation of the equivalent mass limit were not based on the use of dilution as a substitute for treatment pursuant to subsection 8-4-2F. The industrial user must also be in compliance with subsection 8-4-12C regarding the prohibition of bypass.
5. The Pretreatment Coordinator may convert the mass limits of the categorical pretreatment standards of 40 CFR parts 414, 419, and 455 to concentration limits for purposes of calculating limitations applicable to individual industrial users. The conversion is at the discretion of the Pretreatment Coordinator (40 CFR 403.6(c)(7) & (d)).
6. Once included in its permit, the industrial user must comply with the equivalent limitations developed in this subsection B in lieu of the promulgated categorical standards from which the equivalent limitations were derived (40 CFR 403.6(c)(7)).
7. Many categorical pretreatment standards specify one limit for calculating maximum daily discharge limitations and a second limit for calculating maximum monthly average, or four (4) day average, limitations. Where such standards are being applied, the same production or flow figure shall be used in calculating both the average and the maximum equivalent limitation (40 CFR 403.6(c)(8)).
8. Any industrial user operating under a permit incorporating equivalent mass or concentration limits calculated from a production-based standard shall notify the Pretreatment Coordinator within two (2) business days after the user has a reasonable basis to know that the production level will significantly change within the next calendar month. Any user not notifying the Pretreatment Coordinator of such anticipated change will be required to meet the mass or concentration limits in its permit that were based on the original estimate of the long term average production rate (40 CFR 403.6(c)(9)).
9. All industrial users who may be subject to the City's pretreatment program will be notified of the standards that are pertinent to their operation. As the IU master list is updated, the Pretreatment Coordinator will send letters to new businesses describing applicable pretreatment requirements. If a new business is identified as having SIU or CIU status, the letter will state this and describe the requirements of the status, and outline the steps to acquiring an Industrial Wastewater Discharge Permit. If the business is a restaurant or other facility requiring an interceptor, they will be notified of the interceptor requirements listed in Rigby City Code. Additionally, if newly promulgated pretreatment standards alter the status of an existing IU, the master list will be updated, and a letter will be sent notifying them that their status has been changed and that further action is needed.
C. State Pretreatment Standards: Users must comply with Idaho Pretreatment Standards codified in Idaho Administrative Rules and Procedures Act (IDAPA) 58.01.25.370.
D. Local Limits:
1. The Pretreatment Coordinator is authorized to establish local limits pursuant to 40 CFR 403.5(c).
2. Local limits are listed in chapter 8-2 of this code, Sewer User Regulations. The pollutant limits are established to protect against pass through and interference. No user shall discharge wastewater containing in excess of these limits. The limits apply at the point where the wastewater is discharged to the POTW. All concentrations for metallic substances are for total metal unless indicated otherwise. The Pretreatment Coordinator may impose mass limitations in addition to the concentration-based limitations.
3. The Pretreatment Coordinator may develop best management practices (BMPs), by ordinance or in industrial wastewater discharge permits, to implement local limits and the requirements of subsection 8-4-2A.
E. City's Right Of Revision: The City reserves the right to establish, by ordinance or in industrial wastewater discharge permits, more stringent standards or requirements on discharges to the POTW consistent with the purpose of this chapter.
F. Dilution: No user shall ever increase the use of process water, or in any way attempt to dilute a discharge, as a partial or complete substitute for adequate treatment to achieve compliance with a discharge limitation unless expressly authorized by an applicable pretreatment standard or requirement. The Pretreatment Coordinator may impose mass limitations on users who are using dilution to meet applicable pretreatment standards or requirements, or in other cases when the imposition of mass limitations is appropriate. (Ord. 2021-620, 9-2-2021)