(A) Generally. No person shall discharge wastewater containing constituents in excess of the maximum allowable specific pollutant limitations established by the Board of Public Utilities to protect against pass through and interference. Notwithstanding the limitations that are set forth by the Board of Public Utilities, the General Manager may impose more restrictive limitations, or mass limitations in addition to or in place of concentration based limitations, through any industrial user’s discharge permit.
(B) Local limits. The following pollutant limits are established to protect against materials which are toxic to humans, animals, the local environment or which will cause interference or pass through in the POTW. No person shall discharge wastewater containing in excess of the following local limits. With the exception of pH, for which the local limit is an instantaneous limit, and EC, for which the local limit is a monthly average limit, all local limits are daily maximum limits.
Parameter | Local Limit (mg/l unless otherwise noted) |
Parameter | Local Limit (mg/l unless otherwise noted) |
Arsenic | 0.026 |
Boron | 0.630 |
Cadmium | 0.020 |
Chloride | 128 |
Chromium (total) | 0.155 |
Copper | 0.532 |
Electrical conductivity, (µmhos/cm) | (source water + 500) - 4.0 µmhos/cm per mg/L (NH3-N + NO3-N) |
Iron | 1.912 |
Lead | 0.090 |
Manganese | 0.044 |
Mercury | 0.013 |
Molybdenum | 0.065 |
Nickel | 0.136 |
pH (standard units)(allowable range) | 7-11 |
Selenium | 0.070 |
Silver | 0.198 |
Sodium | 113 |
Total oil and grease | 400 |
Zinc | 0.300 |
(1) The above limits may be revised from time to time by the city as may be deemed necessary to protect the POTW from interference and pass through, or as may be required by the applicable federal, state or local pretreatment standards.
(2) The General Manager may impose more restrictive standards or requirements on a discharge he or she deems necessary to comply with the objectives of this chapter, specific prohibitions or the terms of the city’s waste discharge requirements.
(3) The General Manager may authorize discharges containing higher concentrations on a site-specific basis, provided that the concentrations of such discharges shall not cause pass through or interference. Upon approval by the General Manager, site-specific limitations shall be established through the terms specified in the user’s wastewater discharge permit. The General Manager may impose mass limitations in addition to, or in place of, concentration-based limitations, due to reduced water usage by an industrial user.
(4) Excursions above the pH of 11.0 will be allowed, by the General Manager, only when the pH is measured by continuous recorders, and only under the following conditions:
(a) Time interval for the excursion does not exceed 15 minutes for one individual excursion.
(b) Total time for all excursions does not exceed 60 minutes a day (four 15-minute intervals), or 15 minutes per a six-hour time period.
(c) No excursions of any duration are allowed for pH measurements below 7.0 (federal pH minimum, per 40 C.F.R. § 403.5).
(C) Slugs and equalized discharges. No person shall cause the discharge of slugs of water or wastes. Each person producing a discharge of a slug into the public sewers shall construct and maintain, at his or her own expense, a suitable storage and flow control facility to insure the equalization of the discharge over a 24-hour period. The facility shall have a capacity of at least 80% of the total normal volume discharged during a 24-hour production period, unless a smaller size is approved by the General Manager, and the outlet to the sewer shall be equipped with a rate discharge controller or other device approved by the General Manager, the regulation of which shall be directed by the General Manager.
(D) BMPs. The General Manager may develop best management practices (BMPs), by ordinance or in individual wastewater discharge permits, to implement local limits and the requirements of § 7.20.470.
(1995 Code, § 7.20.465) (Ord. 17-03, passed 3-21-2017; Ord. 15-02, passed 5-5-2015)