(A) Except as indicated in Section (B) and (C), below, the user must collect wastewater samples using flow proportional composite collection techniques. In the event flow proportional sampling is infeasible, the Administrator may authorize the use of time proportional sampling or a minimum of four (4) grab samples, where the user demonstrates that this will provide a representative sample of the effluent being discharged. In addition, grab samples may be required to show compliance with instantaneous discharge limits. Using protocols (including appropriate preservation) specified in 40 C.F.R. pt. 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.
(B) Samples for oil and grease, temperature, pH, cyanide, 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, a minimum of four (4) grab samples must be used for pH, cyanide, total phenols, oil and grease, sulfide and volatile organic compounds for facilities for which historical sampling data do not exist; for facilities for which historical sampling area available, the city may authorize a lower minimum. For the reports required by § 4-6-33, the industrial user is required to collect the number of grab samples necessary to assess and assure compliance with applicable Pretreatment Standards and Requirements.
(Ord. CM-93-34, passed 12-13-1993; Am. Ord. 14-12, passed 12-8-2014)