(A) The local discharge limitation for mercury discharged into the city sewage treatment plant (STP) is established at the level of detection (LOD) as set out in § 54.38(D). Mercury sampling procedures, preservation and handling, and analytical protocol for compliance monitoring shall be in accordance with EPA Methods 245.1 and 1631. The LOD, developed in accordance with the procedure specified in 40 C.F.R. 136 shall not exceed 0.2 ug/L for mercury, unless higher levels are appropriate due to matrix interference(s).
(B) The evaluation of potential matrix interference(s) shall include, at a minimum, the following:
(1) A demonstration that the laboratory conducting the analysis is capable of achieving the LOD of 0.2 ug/L in reagent water;
(2) A demonstration that the LOD of 0.2 ug/L cannot be achieved in the effluent; and
(3) A demonstration that an attempt has been made to resolve the matrix interferences.
(C) In cases where true matrix interference can be demonstrated, a discharge-specific LOD will be developed in accordance with the procedure in 40 C.F.R. 136. Discharge-specific LODs will be incorporated into the wastewater discharge permit of the nondomestic user.
(D) Mercury reduction plan. To ensure that the maximum allowable mercury loading to the sewage treatment plant (STP) is not exceeded, the city may require any nondomestic user with a reasonable potential to discharge mercury to develop, submit for approval and implement a mercury reduction plan (MRP). The MRP may be required by permit even if the nondomestic user has not violated the local limit for mercury, but the city has determined that a reasonable potential for such a violation may exist. An MRP may be required in notices of violations, orders or other enforcement actions when the non- domestic user has violated the mercury local limit. At a minimum, an approved MRP shall contain the following:
(1) A written commitment by the user to reduce all nondomestic discharges of mercury to levels below the established level of detection (LOD) (0.2 ug/L) within three years of the MRP’s original approval date;
(2) Within 60 days of notification by the city that a MRP is required, the user shall supply an initial identification of all potential sources of mercury which could be discharged to the sanitary sewer system;
(3) Specific strategies for mercury reduction with reasonable timeframes for implementation, capable of ensuring that mercury discharges will be below the specified LOD within three years;
(4) A program for quarterly sampling and analysis of the nondomestic discharge for mercury in accordance with EPA Methods 245.1 and 1631;
(5) A demonstration of specific, measurable and/or otherwise quantifiable mercury reductions consistent with the goal of reducing mercury discharges below the specified LOD. Where such reductions cannot be demonstrated through normal effluent monitoring (e.g., mercury discharges are already near LOD) the demonstration should incorporate the following:
(a) Internal process monitoring, documenting the results of mercury reduction strategies at sampling locations within the facility (e.g., a program of regular monitoring of sink traps where mercury containing reagents had previously been disposed, but have since been substituted by non-mercury containing compounds);
(b) Internal and/or effluent sampling utilizing clean sampling and analytical methods as referenced by EPA Federal Register. Note that the results of such monitoring will not be used for compliance purposes unless performed in accordance with EPA Method 245.1 and collected at the appropriate compliance measurement location;
(c) Loading calculations wherein the nondomestic user calculates the total mass of mercury reduced from the sanitary sewer discharge through reagent substitutions, changes in disposal practices and/or other approved MRP strategies implemented.
(6) A semi-annual report on the status of the mercury reduction efforts. At a minimum, these reports shall:
(a) Identify compliance or noncompliance with specific reduction commitments in the MRP;
(b) Summarize the analytical, mass-based or other quantifiable demonstrations of mercury reductions performed to date;
(c) Provide all applicable analytical data;
(d) Provide an evaluation of the effectiveness of actions taken to date;
(e) Provide updates to the initial list of mercury containing compounds discharged to the sanitary sewer; and
(f) Propose for approval new strategies and/or modifications to the current MRP to continue and improve mercury reduction efforts.
(7) Any other conditions that the city deems necessary to ensure that mercury reduction efforts are effective in achieving the goals of this section.
(E) Failure to submit an approved MRP within 30 days of the required due date shall constitute significant non-compliance in accordance with this section and will result in publication as a significant violator.
(F) A MRP may be evaluated for adequacy at any time by the city. If such an evaluation determines that the MRP is inadequate, or the nondomestic user has not complied with its approved MRP, the nondomestic user will be notified. Failure to comply with the MRP requirement constitutes non-compliance. The city will follow its Enforcement Response Plan (ERP), as found in §§ 53.80 et seq., to ensure that corrective actions are taken and the public protected.
(G) The city reserves the right to take appropriate enforcement action against any nondomestic user that violates its discharge permit in any way, to include the discharge of mercury into the city system, even if such user has an MRP in place and is making progress toward full compliance.
(H) A nondomestic user may request a release from the MRP requirements if:
(1) All samples of the discharge for a period of one year are less than the specified LOD;
(2) The nondomestic user has complied with at a minimum the monitoring frequency of quarterly sampling events; and
(3) The city deems the MRP commitments have been fulfilled sufficiently to ensure continued compliance with the mercury limitation. The city shall notify the nondomestic user of any release from MRP requirements in writing.
(I) If the MRP requirement is waived by the city, the nondomestic user remains subject to the local limitation for mercury in accordance with the requirements of local and state law.
(J) Rediscovery of mercury in the nondomestic user’s discharge subjects said user to the submission of a new MRP, or escalation of enforcement in accordance with the city’s ERP.
(Ord. 677, passed 8-28-2023) Penalty, see § 54.99