(A)   The following pollutant limitations are established to protect against pass through and interference. No person shall discharge wastewater containing in excess of the following daily. maximum concentrations based upon a 24-hour composite sample. Additionally, no person shall discharge wastewater containing in excess of the following maximum concentrations times a multiplier of 1.5 based upon a grab sample. The 1.5 grab sample multiplier does not apply to Hex. Chromium, Cyanide and Phenols in that analytical procedures do not allow for composite techniques to be applied to these parameters. For Hex. Chromium, Cyanide and Phenols, three grab sample results shall be analyzed with results not to exceed the following noted limitations.
.168 mg/l Arsenic (total)[1]
.034 mg/l Cadmium (total)[1]
.143 mg/l Hex. Chromium
10.8 mg/l Total Chromium
1.13 mg/l Copper[2]
.515 mg/l Cyanide (total)[2]
.40 mg/l Lead (total)[1]
.03 mg/l Mercury (total)[1]
.067 mg/l Molybdenum (total)[1]
2.52 mg/l Nickel[1]
[1]   Limitation determination based upon U.S. EPA 40 CFR Part 503 Biosolids Regulations.
[2]   Limitation determination based upon NPDES Daily Effluent Limitations.
100 mg/l Oil & Grease[3]
.09 mg/l Selenium[1]
.5 mg/l Silver
1.0 mg/l Phenols
3.62 mg/l Zinc (total)[1]
[1]   Limitation determination based upon U.S. EPA 40 CFR Part 503 Biosolids Regulations.
[3]   As an alternative to the total oil and grease limitations established by this section, the Control Authority may establish in an IWP a limitation of 100 mg/1 for non-polar grease. The alternative limitation is subject to the following conditions:
   1.   The user submits an application for the alternative limit;
   2.   The user provides information regarding the user's products, processes, and operations that shows to the Control Authority's satisfaction that the oil and grease discharge by the user is predominantly of animal or vegetable origin;
   3.   The user shows that the oil and grease in the user's discharges is not visible, free, or floating at 50 F at any time;
   4.   The user has sampling facilities that allow for both visual inspections of the user's discharge and using the equipment necessary for collection samples for floatable oil and grease;
   5.   The oil and grease in the user's discharge is not related to past instances of obstruction, interference, or pass though;
   6.   Users subject to the alternative limit shall continue to operate and maintain grease traps and any other oil and grease separation and treatment equipment and shall continue all existing practices that reduce discharge of oil and grease;
   7.   If the Control Authority determines that a user subject to the alternative limits has caused, along or in conjunction with other discharge, obstructions, interference, or pass through, then the user shall comply with the total oil and grease limitation or another appropriate limitation established by the District in the user's IWP; and
   8.   Any other appropriate conditions set forth in the user's SIU.
   (B)   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 Utilities Manager may impose mass limitations in addition to, or in place of, the concentration-based limitations above.
   (C)   Upon the promulgation of the National Categorical Pretreatment Standard (NCPS) for a particular user, the said standard, if more stringent then the limitations imposed under this appendix for sources in that category, shall, when effective, immediately supersede the limitations and conditions imposed under this appendix. The Utility Manager shall notify all known affected users of the applicable permitting and reporting requirements under 40 CFR 403.12.
(Ord. 1998-20, passed 11-17-98; Am. Ord. 2012-19, passed 9-18-12; Am. Ord. 2019-9, passed 12-3-19)