A. Sampling for baseline monitoring reports (BMR) and 90-day compliance reports must include a minimum of four grab samples for pH, cyanide, total phenols, oil and grease, sulfide and volatile organic compounds for facilities for which historical sampling data do not exist. The City may authorize a lower minimum for facilities with historical sampling data. The numbers of grab samples for periodic compliance reports shall be the number the City determines to be necessary to assess and assure compliance by industrial users with applicable pretreatment standards and requirements.

The City will determine on a case-by-case basis whether the user will be able to composite the individual grab samples. For all other pollutants, 24-hour composite samples must be obtained through flow or time-proportional composite sampling techniques, depending on circumstances. The City may waive flow-proportional composite sampling for any user that demonstrates that flow-proportional composite sampling is infeasible. Where time-proportional composite sampling or grab sampling is authorized by the City, the samples must be representative of the discharge and the decision to allow the alternative sampling must be documented in the industrial user file for that facility or facilities. Using protocols (including appropriate preservation) specified in 40 CFR Part 136 and appropriate EPA guidance, multiple grab samples collected during a 24-hour period may be composited prior to the analysis as follows: For cyanide, total phenols, and sulfides the samples may be composited in the laboratory or in the field; for volatile organics and oil and grease the samples may be composited in the laboratory. Composite samples for other parameters unaffected by the compositing procedures as documented in approved EPA methodologies may be authorized by the City, as appropriate.

In those cases, samples may be obtained through time-proportional composite sampling techniques or through a minimum of four grab samples where the user demonstrates that this will provide a representative sample of the effluent being discharged.

B. Samples shall be taken immediately downstream from any pretreatment facilities, immediately downstream from the regulated or manufacturing process if no pretreatment exists, or at a location determined by the City and specified in the user’s wastewater discharge permit. For categorical users, if other wastewaters are mixed with the regulated wastewater prior to pretreatment, the user shall measure the flows and concentrations necessary to allow use of the combined wastestream formula of 40 CFR 403.6(e) in order to evaluate compliance with the applicable categorical pretreatment standards. For other SIUs, for which the City has adjusted its local limits to factor out dilution flows, the user shall measure the flows and concentrations necessary to evaluate compliance with the adjusted pretreatment standard(s). In cases where a local limit requires compliance with a best management practice or pollution prevention alternative, the user must submit documentation required by the City to determine the compliance status of the user.

C. All sample results shall indicate the time, date and place of sampling and methods of analysis and shall certify that the wastestream sampled is representative of normal work cycles and expected pollutant discharges from the user. If a user sampled and analyzed more frequently than required in its wastewater discharge permit, using methodologies in 40 CFR Part 136, it must submit all results of sampling and analysis of the discharge as part of its self-monitoring report. [Ord. NS-2182, 2012]