(1) Except as indicated in Subsections (2) and (3) of this Section, the user must collect wastewater using twenty-four (24) hour flow-proportional composite sampling techniques, unless time-proportional composite sampling or grab sampling is authorized by the Provo City Industrial Pretreatment Coordinator. Where time-proportional composite sampling or grab sampling is authorized by Provo City, the samples must be representative of the discharge. 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 Provo City, as appropriate. In addition, grab samples may be required to show compliance with instantaneous limits.

(2) Samples for oil and grease, temperature, pH, cyanide, total phenols, sulfides, and volatile organic compounds must be obtained using grab collection techniques.

(3) For sampling required in support of baseline monitoring and ninety (90) day compliance reports required in Sections 10.04.260 and 10.04.280, Provo City Code, 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 data are available, the Provo City Industrial Pretreatment Coordinator may authorize a lower minimum. For the reports required by Section 10.04.290, Provo City Code, the industrial user is required to collect the number of grab samples necessary to assess and assure compliance with applicable pretreatment standards and requirements.