Morro Bay Municipal Code Art. II General Sewer Use Requirements

A. 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.

B. Specific Prohibitions. No USER shall introduce or cause to be introduced into the POTW the following pollutants, substances, or wastewater:

1. 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 or one and two-seven hundredths centimeters in any dimension;

2. 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;

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

4. 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;

5. Trucked or hauled pollutants except at discharge points designated by the utilities division/department manager in accordance with this chapter;

6. Septic tank cleanings or any raw or chemically treated sewage from septic tanks;

7. 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;

8. 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 permit;

9. Wastewater containing any radioactive wastes or isotopes except in compliance with applicable state or federal regulations;

10. Stormwater, 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 utilities division/department manager;

11. Sludges, screenings, or other residues from the pretreatment of industrial wastes;

12. Medical wastes, except as specifically authorized by the utilities division/department manager in an industrial wastewater discharge permit;

13. Wastewater causing, alone or in conjunction with other sources, the treatment plant's effluent to fail toxicity test;

14. Detergents, surface-active agents, or other substances which that might cause excessive foaming in the POTW;

15. 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;

16. Any gasoline, benzene, naphtha, fuel oil, or other flammable or explosive liquid, solid, or gas.

C. Narrative and Numerical Limits.

1. 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 F (sixty degrees C) using the test methods specified in 40 CFR 261.21;

2. Wastewater having a pH less than 5.5 or more than 9.0, or otherwise causing corrosive structural damage to the POTW or equipment;

3. Wastewater having a temperature greater than one hundred fifty degrees F (sixty-six degrees C), or 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 F (forty degrees C);

4. Fats, oils, or greases of animal or vegetable origin in concentrations greater than one hundred mg/L;

5. Total petroleum hydrocarbons in concentrations greater than one hundred mg/L;

6. Wastewater causing two readings on an explosion hazard meter at the point of discharge into the POTW, or at any point in the POTW, of more than ten percent or any single reading over five percent of the lower explosive limit of the meter;

7. Wastewater exceeding the five-day biochemical oxygen demand of three hundred mg/L shall be subject to the requirements of Section 13.12.300 of this chapter;

8. Wastewater exceeding the total suspended solids of three hundred fifty mg/L shall be subject to the requirements of Section 13.12.300 of this chapter;

9. Discharges having an average daily flow greater than two percent of the average daily flow of the city shall be subject to the requirements of Section 13.12.300 of this chapter;

10. Wastewater exceeding the following concentrations:

a. Ammonia-N, 50 mg/L,

b. Boron, 8 mg/L,

c. Copper, 1 mg/L,

d. 1,4-Dioxane, 0.0013 mg/L,

e. Mercury, 0.2 mg/L,

f. N-Nitrosodimethylamine (NDMA), 0.000065 mg/L,

g. Sodium, 900 mg/L,

h. Strontium, 1.55 mg/L,

i. Total dissolved solids (TDS), 8,500 mg/L.

(Ord. No. 642, § 1, 1-26-21)

Users must comply with the categorical pretreatment standards found at 40 CFR Chapter I, Subchapter N, Parts 405—471.

A. When wastewater subject to a categorical pretreatment standard is mixed with wastewater not regulated by the same standard, the utilities division/department manager shall impose an alternate limit in accordance with 40 CFR 403.6(e) (combined wastestream formula).

(Ord. No. 642, § 1, 1-26-21)

The utilities division/department manager may develop BMPs in industrial wastewater discharge permits, to implement the requirements of this chapter.

(Ord. No. 642, § 1, 1-26-21)

The city reserves the right to establish, by ordinance, by resolution or in each industrial wastewater discharge permit, more stringent standards or requirements on discharges to the POTW consistent with the purpose of this chapter, when the utilities division/department manager determines that necessary for public safety.

(Ord. No. 642, § 1, 1-26-21)

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 utilities division/department manager 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. No. 642, § 1, 1-26-21)

No person shall discharge or cause to be discharged, any mercury or amalgam waste into the sewer system. All dental dischargers that place or remove amalgam must operate and maintain an amalgam separator that complies with ANSI/ADA Specifications 108 (2009) with Technical Addendum (2011) or ISO 11143 Dentistry-Amalgam Separators. The dental discharger shall comply with the most recent best management practices for dental amalgam waste as recommended by the American Dental Association, and specified in 40 CFR 441 (Effluent Limitations Guidelines and Standards for the Dental Category) June 14, 2017.

(Ord. No. 642, § 1, 1-26-21)