(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 concentrations based upon a 24-hour composite sample. Additionally, no person shall discharge wastewater containing in excess of 1.5 times the following concentrations for any grab sample. Since analytical procedures do not allow for composite sampling techniques when sampling for Hexavalent Chromium and Cyanide, three grab samples shall be analyzed with no single result exceeding the concentration.
0.1 | mg/l Cadmium (total)[2] |
30 | mg/l Chlorine |
0.13 | mg/l Hexavalent Chromium [3] |
2.77 | mg/l Total Chrome [2] |
2.6 | mg/l Copper (total)[3] |
0.2 | mg/l Cyanide (total)[3] |
0.4 | mg/l Lead (total)[3] |
.0003 | mg/l Mercury (total)[3] |
2.9 | mg/l Nickel (total)[3] |
100 | mg/l Oil and grease [1] |
2.6 | mg/l Zinc (total)[3] |
0.85 | mg/l Silver (total) |
[1] As an alternative to the total oil and grease limitations established by this section, the Wastewater Utility Manager may establish in an IWP a limitation of 100 mg/l 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 show to the Wastewater Utility Manager’s satisfaction that the oil and grease discharged 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 inspection 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 through; 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 discharges of oil and grease; 7. If the Wastewater Utility Manager determines that a user subject to the alternative limit has caused, alone or in conjunction with other discharges, obstruction, 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 permit. | |
[2] EPA PSES Categorical Standard (40 C.F.R. part 433). [3] EPA Table 1 Spreadsheet - “Local Limit Determination Based on NPDES Daily Limits”. | |
(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 Wastewater Utility 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) from the EPA for a particular user, the said standard, if more stringent than the limitations imposed under the POTW subchapters for sources in that category shall, when effective, immediately supersede the limitations and conditions imposed under this subchapter. The city, when acting as the permitting authority, shall notify all known affected users of the applicable permitting and reporting requirements under 40 C.F.R. § 403.12.
(Ord. 2008-38, passed 12-10-2008; Ord. 2015-6, passed 7-8-2015; Ord. 2019-25, passed on 5-13-2020)