(A) Except as indicated in subsections (B) and (C) of this section, industrial users must collect wastewater samples using twenty four (24) hour flow proportional composite sampling techniques, unless time proportional composite sampling or grab sampling is authorized by the city. Where time proportional composite sampling or grab sampling is authorized by the city, the samples must be representative of the discharges and authorization documentation included in the users' files. Using protocols (including appropriate preservation) specified in 40 CFR part 136 and appropriate EPA guidance, multiple grab samples collected during a twenty four (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 addition, grab samples may be required to show compliance with instantaneous limits.
(B) Samples for oil and grease, temperature, pH, cyanide, total phenols, sulfides, and volatile organic compounds must be obtained using grab collection techniques.
(C) For sampling required in support of baseline monitoring and ninety (90) day compliance reports required in sections 7-7-4-1 (pertaining to BMRs), 7-7-4-2 (pertaining to FCRs), and 7-7-4-3 (pertaining to periodic compliance reports for categorical and noncategorical SIUs) of this chapter, a minimum of four (4) grab samples must be used for pH, cyanide, total phenols, oil and grease, sulfides and volatile organic compounds for facilities for which historical sampling data do not exist; for facilities for which historical sampling data are available, the city may authorize a lower minimum. For the reports, the industrial user is required to collect the number of grab samples necessary to assess and assure compliance with applicable pretreatment standards and requirements.
(D) Samples shall be taken immediately downstream from pretreatment facilities if such exist, 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 industrial 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 waste stream formula at 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). Where an alternate concentration or mass limit has been calculated in accordance with 40 CFR 403.6(e) the adjusted limit along with supporting data shall be submitted to the city and included in the industrial user's file.
(E) All sample results shall indicate the time, date and place of sampling and methods of analysis and shall certify that the waste stream sampled is representative of normal work cycles and expected pollutant discharges from the user. If a user sampled and analyzed more frequently than what was required in its industrial 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. 2020-018, 10-19-2020)