A. No person or industrial discharger shall discharge wastewater containing in excess of the following instantaneous maximum allowable limitations:
Pollutant | Instantaneous Maximum Allowable Discharge Limit (mg/l) |
Arsenic | 0.05 |
Cadmium | 0.02 |
Chromium | 3.44 |
Copper | 1.97 |
Cyanide | 0.16 |
Lead | 0.30 |
Mercury | 0.02 |
Nickel | 2.86 |
Silver | 0.76 |
Zinc | 0.64 |
B. No person or industrial user shall discharge wastes with an electrical conductivity in excess of the flow weighted average EC of the source water plus five hundred (500) umhos/cm or a total of one thousand (1,000) umhos/cm, whichever is lower, except as provided for below.
C. To promote and encourage water conservation efforts, the maximum allowable electrical conductivity may be adjusted as determined by the following formulas and definitions
1. Definitions
"EC regulatory" shall mean flow weighted average EC of the source water plus five hundred (500) umhos/cm or a total of one thousand (1,000) umhos/cm, whichever is lower. Flow weighted average EC for source water shall be based on the local public or private water supplier's annual water quality report.
"EC industry" shall mean derived flow weighted monthly average EC permit limit for an industrial user. The maximum EC industry value due to water conservation efforts is one thousand (1,000) umhos/cm.
"EC small industry" shall mean derived flow weighted monthly average EC permit limit for an industrial user discharging less than five thousand (5,000) gallons per day.
"Flow industry" shall mean measured or estimated wastewater flow volume for an industrial user.
"Flow conserved" shall mean documented and verified process wastewater flow volume reduction due to water conservation efforts.
"Flow small industry" shall mean measured or estimated wastewater flow volume for an industrial user that is less than five thousand (5,000) gallons per day.
2. Formulas.
EC Industry = [EC Regulatory x (Flow Industry + Flow Conserved)]
__ ___________________________
(Flow Industry)
For industries with measured or estimated wastewater flow that is less than five thousand (5,000) gallons per day, the following formula is utilized.
EC Small Industry = [EC Regulatory x (0.005 MGD + Flow Conserved)]
_ __________________________
(Flow Small Industry)
3. Those industries that have EC limits higher than those listed above resulting from a previous action are grandfathered with their existing limit. For grandfathered EC limits, no credit for water conservation measures may be taken to obtain a higher EC limit.
D. Notwithstanding the limitations that are set forth in subsection (A) of this section:
1. The city may impose more restrictive standards or requirements on discharges if it is deemed necessary to comply with the objectives of this ordinance, specific prohibitions or the terms of the city's NPDES permit;
2. The city may authorize discharges containing higher concentrations of specific pollutants on a site- specific basis, provided that the concentrations of such discharges shall not cause pass through or interference. Upon approval by the city, site-specific limitations shall be established through the terms specified in the discharger's industrial discharge permit. The city may impose mass limitations in addition to, or in place of, concentration based limitations. However, no special agreement shall be allowed to contravene federal, state or local pretreatment standards.
E. No person or industrial 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 city may impose mass limitations on industrial users which are using dilution to meet applicable pretreatment standards or requirements, or in other cases when the imposition of mass limitations is appropriate. (Ord. 2011-08 § 4, 2011: Ord. 2006-02 (part), 2006: Prior code § 4252)