§ 24-85. Local limits.

(a)

Limitations on wastewater strength and flow rate. No person or user shall discharge wastewater in excess of the concentration set forth in the following table unless the wastewater discharge permit of the user provides as a special permit condition a higher interim concentration level in conjunction with a requirement that the user construct a pretreatment facility or institute changes in operations and maintenance procedures to reduce the concentration of pollutants to levels not exceeding the standards set forth in the table within a fixed period of time. In no case shall peak discharge have a flow rate that exceeds one and five-tenths (1.5) times the average flow rate during the normal operation or production period.

(b)

Industrial discharge limits for a POTW operating under a 15.0 mgd NPDES permit.

Pollutant*	Concentration mg/l at Industry Effluent
Arsenic	.02
Cadmium	.01
Chromium (T)	.67
Copper	.11
Cyanide	.13
Lead	.12
Mercury	.002
Molybdenum	.13
Nickel	.26
Phenol	2.13
Selenium	.02
Silver	.70**
Zinc	.30
BOD	850.00
TSS	1,500.00
COD	2,500.00

 

* Sampling and analysis shall be performed in accordance with the technique described in 40 CFR Part 136, 40 CFR Part 403.12 (b) (5) (iii) and (vi) and amendments thereto which specify grab samples to be used for pH, cyanide, total phenols, oil and greases, sulfides and volatile organic. For all other pollutants, twenty-four-hour composite samples must be obtained through flow proportional composite sampling techniques, unless deemed infeasible for an industrial user on a case-by-case basis by the city.

** The current EPD detection limit for silver is 0.010 mg/l. For industry to be in compliance with this limit, results reported to the city should be analyzed to the thousandths of the number or written as less than 0.010 mg/l (<0.010 mg/l).

(c)

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, or in place of, the concentration-based limitations above.

(Ord. No. 11-97, 4-10-97; Ord. No. 10-01, 3-15-01)