Chico Municipal Code Art. II Discharge Restrictions

No user shall introduce or cause to be introduced into the city’s sanitary sewer system any pollutant or wastewater which causes pass through or interference. These general prohibitions apply to all users of the city’s sanitary sewer system whether or not they are subject to categorical pretreatment standards or any other federal, state, or local pretreatment standards or requirements.

(Ord. 2481 §1 (part))

No user shall introduce or cause to be introduced into the city’s sanitary sewer system any of the following pollutants, substances, or wastewater:

1. Pollutants which create a fire or explosive hazard in the city’s sanitary sewer system with a closed cup flashpoint of less than 140° degrees Fahrenheit (60 degrees centigrade) using the test methods specified in 40 CFR Part 261.21. Prohibited materials include, but are not limited to, gasoline, kerosene, naphtha, benzene, toluene, xylene, ethers, alcohols, ketones, aldehydes, peroxides, chlorates, perchlorates, bromates, carbides, hydrides, or sulfides. Closed cup flashpoint values may be found in the National Institute of Occupational Safety and Health (NIOSH) Pocket Guide to Chemical Hazards;

2. Wastewater having a pH lower than 5.0 or more than 11.5, or otherwise capable of causing damage or hazard to the city’s sanitary sewer system;

3. Solids or viscous substances, including, but not limited to, fats, oils, or grease, garbage with particles greater than one-half inch in any dimension, animal guts or tissues, paunch manure, bones, hair, hides or fleshings, entrails, whole blood, feathers, ashes, cinders, sand, spent lime, stone or marble dust, metal, glass, straw, shavings, grass clippings, rags, spent grains, spent hops, wastepaper, wood, plastics, gas, tar, asphalt residues, residues from refining or processing of fuel or lubricating oil, mud, or glass grinding or polishing wastes, which may cause obstruction of flow in the sewer or other inference with the operation of the city’s sanitary sewer system;

4. Pollutants including oxygen demanding pollutants (BOD, COD, 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 to the city’s sanitary sewer system;

5. Wastewater having a temperature greater than 140 degrees Fahrenheit (60 degrees centigrade), or which will inhibit biological activity in the water pollution control plant resulting in interference, but, in no case, wastewater which causes the temperature, at the introduction into the water pollution control plant which to exceeds 140 degrees Fahrenheit (60 degrees centigrade);

6. Petroleum oil, nonbiodegradable cutting oil, or products of mineral oil origin that will cause interference or pass through;

7. Pollutants which result in the presence of toxic gases, vapors or fumes within the city’s sanitary sewer system in a quantity that may cause acute worker health and safety issues;

8. Trucked or hauled wastes, except at discharge points designated by the director;

9. Noxious or malodorous liquids, gases, or solids, which either singly or by interaction with other wastes, are sufficient to create a public nuisance or hazard to life, or are sufficient to prevent entry into the city’s sanitary sewer system for maintenance and repair;

10. Wastewater that may cause a detrimental environmental impact or nuisance in the waters of the state or United States that is unacceptable to any public agency having regulatory jurisdiction over the city;

11. Wastewater which imparts color which cannot removed in the treatment process, such as, but not limited to, dye wastes and vegetable tanning solutions;

12. Wastewater causing two readings on an explosion hazard meter at the point of discharge into the city’s sanitary sewer system (or at any point in the city’s sanitary sewer system) of more than five (5) percent nor any single reading over ten (10) percent of the lower explosive limit (LEL) of the meter. Prohibited materials include, but are not limited to, gasoline, kerosene, naphtha, benzene, toluene, xylene, ethers, alcohols, ketones, aldehydes, peroxides, chlorates, perchlorates, bromates, carbides, hydrides, sulfides, and any other substances in any quantity or concentration that the city, state, or USEPA has notified the user are a fire hazard or a hazard to the city’s sanitary sewer system;

13. Wastewater containing algaecides, fungicides, antibiotics, insecticides, strong oxidizing agents or strong reducing agents in such quantity or strength as to cause or contribute to violations of the city’s NPDES permit discharge restrictions, interference with or upset of the city’s sanitary sewer system, or personnel safety hazards;

14. Medical waste, except as specifically authorized by the director, in a wastewater discharge permit;

15. Wastewater requiring an excessive quantity of chlorine or other chemical compound used for disinfection purposes;

16. Wastewater containing radioactive wastes or isotopes of such half-life or concentration as may exceed limits established by the director in compliance with any applicable state or federal regulations;

17. Wastewater that causes a hazard to human life or creates a public nuisance;

18. Wastewater containing toxic pollutants, gases, vapors, or fumes in sufficient quantity, which either singly or by interaction with other pollutants, may injure or interfere with any wastewater treatment process, cause acute worker health and safety problems, constitute a hazard to humans or animals, create a toxic effect in the receiving waters of the city’s sanitary sewer system, result in exceedances of biosolids disposal restrictions, or exceed the limitation set forth in a pretreatment standard or requirement. A toxic pollutant shall include, but not be limited to, any pollutant identified pursuant to section 307(a) of the Act;

19. Stormwater, rainwater, groundwater, street drainage, subsurface drainage, yard drainage, and cooling water, including evaporative type air cooler discharge water and noncontact cooling water;

20. Wastewater containing sulfides in sufficient quantity or strength as to cause or contribute to corrosion in the city’s sanitary sewer system or violations of the city’s NPDES permit; or

21. Discharges which, if otherwise disposed of, would be a hazardous waste under 40 CFR Part 261.

Pollutants, substances, or wastewater prohibited by section 15.40.021 of this chapter shall not be processed or stored in such a manner that they could be discharged into the city’s sanitary sewer system.

(Ord. 2481 §1 (part))

Users must comply with the categorical pretreatment standards found in 40 CFR Chapter I, Subchapter N, sections 405-471, as amended.

Upon the promulgation of categorical pretreatment standards for a particular industrial subcategory, the categorical pretreatment standards, if more stringent than limitations imposed under this chapter for sources in that subcategory, shall immediately supersede the limitations imposed under this chapter. The director shall attempt to notify all known affected users of the applicable reporting requirements under 40 CFR Part 403.12, or other applicable pretreatment requirements. Provided, however, that in no case shall the failure of the director to notify a user constitute a defense to noncompliance with any such requirement, statute or regulations, or to noncompliance with the provisions of this chapter.

Modifications to the categorical pretreatment standards may occur under the following situations:

1. Where the city’s sanitary sewer system achieves consistent removal of pollutants limited by pretreatment standards, the director may apply to the Administrator for modification of specific limits in the pretreatment standards. Upon approval from the Administrator, the director may modify pollutant discharge limits in the pretreatment standards if the requirements contained in 40 CFR Part 403.7 are fulfilled.

2. When the limits in a categorical pretreatment standard are expressed only in terms of either the mass or the concentration of a pollutant in wastewater, the director may impose equivalent concentration or mass limits in accordance with 40 CFR Part 403.6(c).

3. When wastewater subject to a categorical pretreatment standard is mixed with wastewater not regulated by the same standard, the director shall impose an alternate limit, using the combined wastestream formula in 40 CFR Part 403.6(e).

4. A user otherwise classified as a CIU may obtain a variance from a categorical pretreatment standard if the user can prove, pursuant to the procedural and substantive provisions in 40 CFR Part 403.13, that factors relating to its discharge are fundamentally different from the factors considered by USEPA when developing the categorical pretreatment standard.

5. A CIU may obtain a net gross adjustment to a categorical pretreatment standard in accordance with 40 CFR Part 403.15.

(Ord. 2481 §1 (part))

Users must comply with all applicable state pretreatment standards.

(Ord. 2481 §1 (part))

The director is authorized to establish local limits pursuant to 40 CFR Part 403.5(c). Local limits are established to protect against pass through and interference. No wastewater discharge shall exceed the local limits as determined by the director pursuant to section 15R.40.010 of this code.

The local limits apply at the point where wastewater is discharged into the city’s sanitary sewer system. The director may impose mass limitations in addition to or in lieu of the concentration-based limitations above.

The director may develop BMPs, by ordinance, or in wastewater discharge permits, to implement the local limits and requirements of sections 15.40.020 and 15.40.021.

(Ord. 2481 §1 (part))

The city reserves the right to establish, by ordinance or wastewater discharge permit, more stringent standards or requirements on discharges to the city’s sanitary sewer system, if deemed necessary to comply with the objectives of this chapter or the Act.

(Ord. 2481 §1 (part))

No user shall 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 the discharge limitations contained in the pretreatment standards or requirement.

The director 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. 2481 §1 (part))