(a) The following pollutant limits are established to protect against pass through and interference and reflect the application of reasonable treatment technology. No person shall discharge wastewater in excess of the limits.

(b) The below limits specified in PMC 13.90.090 and 13.90.100 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 Public Works Director may impose mass limits in addition to a concentration-based limits.

(c) Users discharging pollutants in excess of the concentration limits by more than the threshold amount must apply for a permit. Such users shall be subject to surcharges as established by the Public Works Director under the authority of this chapter up to the ceiling loading limit established by permit.

Formula: surcharge concentration = (discharge concentration – threshold concentration) x flow, MGD x 8.34 lbs/gal.

For example, a user discharges 2,000 gallons per day of BOD at 450 mg/l. The surcharge concentration would be 450 mg/l – 300 mg/l, or 150 mg/l, which when multiplied by 0.002MGD (2,000 gpd divided by 1,000,000 to convert to million gallons) and 8.34 lbs/g yields 2.5 lbs/d.