(1) General Discharge 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 Discharge 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, waste streams 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 5.0 or more than 11.5, 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 0.5 inches 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 greater than one hundred fifty degrees Fahrenheit (150°F) at the point of discharge into the sewer collection system; or 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) unless the approval authority, upon the request of the POTW, approves alternate temperature limits;
F. Petroleum oil, non-biodegradable 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 City.
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 NPDES/IPDES permit. Color (in combination with turbidity) shall not cause the treatment plant effluent to reduce the depth of the compensation point for photosynthetic activity by more than ten percent (10%) from the seasonably established norm for aquatic life;
K. Wastewater containing any radioactive wastes or isotopes except as specifically approved by the Public Works Director, 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, non-contact cooling water, except as specifically approved by the Public Works Director by permit/special agreement and in compliance with applicable State or Federal regulations;
M. Any sludges, screenings, or other residues from the pretreatment of industrial wastes or from industrial processes except as specifically approved by the Public Works Director by permit/special agreement and in compliance with applicable State or Federal regulations;
N. Medical wastes, except as specifically authorized by the Public Works Director by permit/special agreement and in compliance with applicable State or federal regulations;
O. Wastewater causing, alone or in conjunction with other sources, the treatment plant's effluent to fail a 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, animal guts or tissues, paunch manure, bones, hair, hides or fleshings, entrails, whole blood (substantially blood - excludes incidental and non-process blood ordinary to wastewater), feathers, ashes, cinders, sand, spent lime, stone or marble dusts, metal, glass, straw, shavings, grass clippings, rags, spent grains, spent hops, wastepaper, wood, plastics, petroleum fuel or gasoline, tar asphalt residues, used lubricating oils, antifreeze, 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 NPDES/IPDES and/or other disposal system permits;
T. Any wastewater, which in the opinion of the Public Works Director can cause harm either to the sewers, sewage treatment process, or equipment; have an adverse effect on the receiving stream; or can otherwise endanger life, limb, public property, or constitute a nuisance, unless allowed by the Public Works Director by permit/special agreement and in compliance with applicable state or federal regulations (except that no special waiver shall be given from categorical pretreatment standards);
U. The contents of any tank or other vessel owned or used by any person in the business of collecting or pumping sewage, effluent, septage, or other wastewater unless said person has first obtained testing and approval as has been specifically approved by the Public Works Director by permit/special agreement and in compliance with applicable State or Federal regulations and paid all fees assessed for the privilege of said discharge;
V. Any hazardous wastes as defined in rules published 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);
X. 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 except as specifically approved by the Public Works Director by permit/special agreement and in compliance with applicable State or Federal regulations.
(3) Limitations On Wastewater Strength:
A. National Categorical Pretreatment Standards: National Categorical Pretreatment Standards specified in the 40 CFR chapter I, subchapter N, Parts 405-471 are hereby incorporated as promulgated by the U.S. Environmental Protection Agency pursuant to the Clean Water Act shall be met by all dischargers of the regulated industrial categories. All categorical pretreatment standards shall apply at the discharge of the treated categorical waste stream, "end-of-process." A user subject to a categorical pretreatment standard must also comply with the discharge regulations and pollutant limitations as set forth in this section except as may be allowed by permit or special agreement ("Individual Limits") provided such allowance shall not authorize discharge of any pollutant in excess of said permit, agreement, or the applicable categorical limits or national pretreatment standards. Special agreements must be documented as to why the local limit is being lifted. Special agreements cannot cause the WWTP to exceed its permit limits.
B. Local Limits For Specific Pollutants: The following pollutant limits are established to protect against pass through and interference. All concentrations for metallic substances are for "total" metals unless indicated otherwise. Where a user is subject to a categorical pretreatment standard and a local limit for a given pollutant, the more stringent limit shall apply. The Director can approve a discharge greater than the local limit, but not above the categorical limit as long as the agreement does not cause the POTW to violate its permit limits. Public Works Director.
(1) Heavy Metals And Similar Toxic Substances: No person shall discharge wastewater containing in excess of the following daily maximum allowable discharge limits:
Pollutant | Maximum Daily Concentration Limit | Units |
Pollutant | Maximum Daily Concentration Limit | Units |
Arsenic, Total | 0.02 | mg/L |
Cadmium, Total | 0.5 | mg/L |
Chromium, Total | 2.8 | mg/L |
Copper, Total | 1.8 | mg/L |
Cyanide, Total | 0.3 | mg/L |
Lead, Total | 0.6 | mg/L |
Mercury, Total | 0.001 | mg/L |
Nickel, Total | 1.0 | mg/L |
Silver, Total | 0.7 | mg/L |
Zinc, Total | 3.5 | mg/L |
(2) Conventional Pollutants: The following discharges of pollutants released in such strength or volume as to cause interference or pass-through in the treatment process are not permitted unless approved otherwise in writing by the Public Works Director either by permit or by special agreement in accordance with the provisions of this article. The following are maximum daily limits:
Pollutant | Permit Required | Units |
5-Day Biochemical Oxygen Demand (BOD5) | 400 | mg/L |
Total Suspended Solids (TSS) | 400 | mg/L |
Fat, Oil & Grease (FOG) | 100 | mg/L |
C. Limits Applied At "End-of-Pipe": The above limits apply at the point where the wastewater is discharged to the POTW (end-of-pipe).
(4) Best Management Practices: The Superintendent may develop and enforce Best Management Practices (BMP's), by ordinance or in individual wastewater discharge permits, to implement local limits and the requirements of general discharge prohibitions and specific discharge prohibitions in subsections (1) and (2).
(5) Flow: No person shall discharge wastewater into the POTW at a flow rate and/or pollutant discharge rate which is excessive over a relatively short time period which causes a treatment process upset and subsequent loss of treatment efficiency.
(6) Dilution: No user shall, unless specifically authorized by the Public Works Director, increase the use of potable or process water in any way, nor mix separate waste streams for the purpose of diluting a discharge as a partial or complete substitute for adequate treatment to achieve compliance with the standards set forth in this article.
(7) Special Agreement: The City reserves the right to enter into special agreements with a user setting out special terms under which it may discharge to the POTW. In no case will a special agreement waive compliance with a categorical pretreatment standard or federal pretreatment requirement. However, the user may request a net gross adjustment to a categorical standard in accordance with 40 CFR 403.15. They may also request a variance from the categorical pretreatment standard from the approval authority. Such a request will be approved only if the user can prove that factors relating to its discharge are fundamentally different from the factors considered by EPA when establishing that categorical pretreatment standard. A user requesting a fundamentally different factor variance must comply with the procedural and substantive provisions in 40 CFR 403.13.
(8) Pretreatment Facilities: A user shall provide necessary wastewater treatment as required to comply with this Article, and the use and management/facilities plan shall achieve compliance with all applicable pretreatment standards and requirements set out in this article within the time limitations specified by the EPA, Idaho DEQ, or the Public Works whichever is more stringent. Any facilities required to pretreat wastewater to a level acceptable to the City shall be provided, operated, and maintained at the user's expense. Detailed plans showing the pretreatment facilities and operating procedures shall be submitted to the City for review, and shall be acceptable to the City before construction of the facility. The review of such plans and operating procedures will in no way relieve the user from the responsibility of modifying the facility as necessary to produce an acceptable discharge to the POTW under the provisions of this article.
(9) Compliance Deadline: Deadline for compliance with applicable pretreatment standards and requirements by existing users (categorical users) covered by categorical pretreatment standards shall be within three (3) years of the date the standard is effective unless a shorter compliance time is specified in the appropriate standard. The City shall establish a final compliance deadline date for any existing user not covered by categorical pretreatment standards or for any categorical user when the local limits for said user are more restrictive than EPA's categorical pretreatment standards.
New source dischargers and "New Users" that are considered significant industrial users (SIU) are required to comply with applicable pretreatment standards within the shortest feasible time (not to exceed ninety (90) days from the beginning of discharge). New sources and "New Users" shall install and have in operating condition and shall "startup" all pollution control equipment required to meet applicable pretreatment standards before beginning to discharge.
Any wastewater discharge permit issued to a categorical user shall not contain a compliance date beyond any deadline date established in EPA's categorical pretreatment standards. Any existing user or a categorical user which is in non-compliance with one or more local limits shall be provided with a compliance schedule placed in an industrial wastewater permit to ensure compliance within the shortest time feasible. See subsection 04-07-17(5) for further detain on compliance schedules.
(10) Additional Pretreatment Measures: The Public Works Director may:
A. Require a user to restrict its discharge during peak flow and/or designate that certain wastewater be discharged only into specific sewers, relocate, consolidate points of discharge, separate sewage waste streams from industrial waste streams, and/or impose other conditions necessary to protect the POTW and to determine the user's compliance with said requirements;
B. Issue a wastewater discharge permit solely for flow equalization;
C. Require that grease, oil, and sand interceptors be provided when he or the POTW deems it necessary for the proper handling of wastewater containing excessive amounts of grease and oil, or sand; provided, however that:
1. Such interceptors shall not be required for residential user;
2. Such interception units shall be of a type and capacity approved by the Public Works Director and shall be so located to be easily accessible for cleaning and inspection;
3. Such interception units shall be located outside of the public right-of-way and outside of utility easements;
4. Such interceptors shall be inspected, cleaned, and repaired regularly in accordance with established BMPs, for their reasonable operational efficiency by the user at the user's expense;
5. The introduction of chemical, bacteria, enzyme or any other additive into an interceptor, directly or indirectly, that cause interference with the normal operation of the unit or causes pass through of prohibited substances is prohibited, unless specifically otherwise authorized by the Public Works Director, Superintendent, or his or her designee.
6. Interceptor maintenance and cleaning records shall be maintained by the user and made available to pretreatment inspectors for review upon request.
D. Require a user with the potential to discharge flammable substances to install and maintain an approved combustible gas detection meter.
(11) Accidental Discharge/Slug Control Plans: The Public Works Director shall evaluate whether each SIU needs an accidental discharge/slug discharge control plan or other action to control slug discharges. The Public Works Director may require any user to develop, submit for approval, and implement such a plan or take such other action that may be necessary to control slug discharges. Alternatively, the Public Works Director may develop such a plan for any user. An accidental discharge/slug discharge control plan shall address, at a minimum, the following:
A. Description of discharge practices, including non-routine batch discharges;
B. Description of stored chemicals;
C. Procedures for immediately notifying the POTW of any accidental or slug discharge. Such notification must also be given for any discharge which would violate any of the standards in subsections (2) and (3) of this section;
D. Procedures to prevent adverse impact from any accidental or slug discharge. Such procedures include, but are not limited to, inspection and maintenance of storage areas, handling and transfer of materials, loading and unloading operations, control of plant site runoff, worker training, building of containment structures or equipment, measures for containing toxic organic pollutants, including solvents, and/or measures and equipment for emergency response.
E. Within five (5) days following an accidental discharge, the user shall submit to the Public Works Director a detailed written report describing the cause of the discharge and the measures to be taken by the user to prevent similar future occurrences. Such notification shall not relieve the user of any expense, loss, damage, or other liability which may be incurred as a result of damage to the POTW, fish kills, or any other damage to person or property; nor shall such notification relieve the user of any fines, civil penalties, or other liability which may be imposed by this article or other applicable law.
F. Signs shall be permanently posted in conspicuous places on the user's premises advising employees whom to call in the event of a slug or accidental discharge. Employers shall instruct all employees who may cause or discover such a discharge with respect to emergency notification procedures.
G. Significant industrial users are required to notify the POTW immediately of any changes at its facility affecting potential for a slug discharge.
(12) Septic Tank Wastes:
A. Septic tank wastes may be introduced into the POTW only at a designated receiving structure within the treatment plant area, and at such times as are established by the Public Works Director. Such wastes shall not violate this section or any other requirements established or adopted by the City. Wastewater discharge permits for individual vehicles to use such facilities shall be issued by the Public Works Director in accordance with subsection 04-07-15(1)B of this article.
B. No load may be discharged without prior consent of the Treatment Plant Superintendent or his authorized designee. The Superintendent may collect samples of each hauled load to ensure compliance with applicable pretreatment standards. The Superintendent may require the hauler to provide a waste analysis of any load prior to discharge.
C. Septage haulers must provide a waste-tracking form for every load. This form shall include, at a minimum, the name and address of the waste hauler, permit number, truck identification, sources of waste, and volume and characteristics of waste.
D. Under no conditions shall the Superintendent accept trucked or hauled wastes into the Caldwell sewer system that are classified as hazardous wastes under the Resource Conservation and Recovery Act or by Idaho Statutes, or rules adopted by the Idaho Legislature pursuant to the Idaho Administrative Procedures Act. (Ord. 2751, 6-16-2008; Ord. 3364, 8-16-2021)