(a) National Categorical Pretreatment Standards.
(1) Users must comply with the categorical pretreatment standards found in 40 CFR Chapter I, Subchapter N, Parts 405-471, where applicable. A Categorical Industrial User (CIU) may obtain a variance from a categorical pretreatment standard if the CIU can prove, pursuant to the procedural and substantive provisions in 40 CFR 403.13, that factors relating to its discharge are fundamentally different from the factors considered by EPA when developing the categorical pretreatment standard.
(2) Where a categorical pretreatment standard is expressed only in terms of either the mass or the concentration of a pollutant in wastewater, the Superintendent 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 CIU. This conversion is at the discretion of the Superintendent.
(3) When wastewater subject to a categorical pretreatment standard is mixed with wastewater not regulated by the same standard, the Superintendent shall impose an alternate limit in accordance with 40 CFR 403.6(e).
(4) Many categorical pretreatment standards specify one limit for calculating maximum daily discharge limitations and a second limit for calculating maximum monthly average, or four-day average, limitations. If such standards are being applied, the same production or flow value shall be used in calculating both the average and the maximum equivalent limitation.
(5) Any SIU must notify the Superintendent at least 30 days in advance of any substantial change in the volume or character of pollutants in their discharge, including any listed or characteristic hazardous wastes for which the industrial user has submitted initial notification under 40 C.F.R. 403.12(p).
(b) State requirements. State requirements and limitations on discharge to the POTW shall be met by all users which are subject to such standards in any instance in which they are more stringent than federal requirements and limitations as those in this chapter or any other applicable ordinance.
(c) Local Limits. The Superintendent is authorized to establish Local Limits pursuant to 40 CFR 403.5(c). These pollutant limits are established to protect against pass through and interference.
(1) No person shall discharge wastewater containing in excess of the following concentrations for any of the enumerated materials, exceeding the following one-day maximums based upon 24-hour average values after a period of nine months has elapsed from the effective date of this chapter:
Pollutant | Concentration (mg/l) |
Pollutant | Concentration (mg/l) |
Arsenic | 0.02 |
Cadmium | 0.4 |
Chromium Hexavalent | None |
Chromium - total | 3.0 |
Copper | 1.0 |
Total cyanide | 1.0 |
Lead | 0.5 |
Mercury | BMP* |
Molybdenum | 0.5 |
Nickel | 2.0 |
Selenium | 0.02 |
Silver | 1.0 |
Zinc | 2.0 |
Fats, oils, & grease | 50 |
BOD5 | 300 |
Suspended solids | 350 |
*BMP Best Management Practices | |
(2) The above 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 Superintendent may impose mass limitations in addition to the concentration-based limitations above.
(3) The Superintendent may develop Best Management Practices (BMPs), by ordinance or in an individual wastewater discharge permit, as local limits in order to achieve the requirements of § 1042.12.
(d) Right of revision. The city reserves the right to amend this chapter, or an individual wastewater discharge permit to provide for different limitations or requirements on discharges to the POTW where deemed necessary to comply with the objectives set forth in § 1042.01.
(e) Dilution. No discharge shall increase the use of potable or process water in any way 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 chapter. This shall not prohibit the use of equalization tanks utilized to regulate flows.
(Ord. 32-84, passed 4-15-1985; Ord. 29-97, passed 8-4-1997; Ord. 27-2017, passed 12-4-2017)