§ 55.072 LOCAL LIMITS.

   (A)   In order to insure optimum and efficient operation of the city wastewater treatment facilities, a table of “Protection Criteria Parameters and Local Effluent Limits for Industrial Users” is included as Table 1. This table establishes maximum effluent limits for individual discharges.

Table 1 Protection Criteria Parameters and Local Effluent Limits for Users
Constituent	Daily Maximum Concentration (mg/l)
Compatible pollutants:
Biochemical oxygen demand	300
Chemical oxygen demand	600
Total suspended solids	300
Nitrogen (Total Kjeldahl)	60
Nitrogen (ammonia)	20
Fats, oil and grease	100
pH	6-9
Incompatible pollutants:
Arsenic	0.60
Cadmium	0.007
Chromium, total	0.88
Chromium, hexavalent	No limit
Copper	0.39
Cyanide, amenable	0.16
Lead	0.14
Mercury	0.0005
Nickel	1.25
Phosphorus (total)	10.0
Selenium	0.10
Silver	0.24
Zinc	2.50
Based on 24-hour flow proportional composite samples. Based on design capacity of plant BDL (below detectable limit).

 

   (B)   Additional constituents shall be added as needed to protect the treatment works.

   (C)   Dilution of any wastewater discharge for the purpose of satisfying these requirements shall be considered a violation of the industrial permit and this chapter.

   (D)   Slugs as defined in this chapter shall be avoided.

   (E)   Wastewater discharges which substantially differ in nature or constituents from the users average discharge shall be prohibited unless prior approval is obtained, in writing, from the Superintendent.

   (F)   In the event that the influent at the POTW reaches or exceeds acceptable levels, the Superintendent shall initiate technical studies to determine the cause of the influent violation and shall recommend to the city the necessary remedial measures, including, but not limited to, recommending the establishment of new or revised pretreatment levels for these parameters. The Superintendent shall also recommend charges to any of these criteria in the event that: the POTW effluent standards are changed, there are changes in any applicable law or regulation affecting same, or changes are needed for more effective operation of the POTW.

   (G)   In addition, wastes excluded from discharge into the city’s sewerage system, as detailed in § 55.070 shall be part of the local effluent limits.

   (H)   The limits for compatible pollutants may be exceeded if it is addressed in the industrial discharge permit and the applicable surcharge (§ 55.209) is paid by the industry.

   (I)   National pretreatment standard: categorical standards or state pretreatment standards shall govern if more stringent than the local limits established above.

   (J)   The city reserves the right to establish, by ordinance or in individual wastewater discharge permits, more stringent standards or requirements on discharges to the POTW consistent with the purpose of this chapter.

(Ord. 610.1-07-08-13, passed 7-8-2013; Ord. 2018-002, passed 3-26-2018; Ord. 2023-004, passed 1-23-2023) Penalty, see § 55.999