(a) Except as indicated in subsection (b) and (c) below, the user shall collect wastewater samples using 24 hour flow proportional composite collection techniques. In the event flow proportional sampling is not feasible, the director may authorize the use of time proportional sampling or a minimum of four grab samples where the user demonstrates that this will provide a representative sample of the effluent being discharged. Using protocols (including appropriate preservation) specified in 40 C.F.R. 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 addition, grab samples may be required to show compliance with instantaneous discharge limits.
(b) Samples for oil and grease, temperature, pH, cyanide, phenols, sulfides and volatile organic compounds shall be obtained using grab collection techniques.
(c) For sampling required in support of baseline monitoring and 90-day compliance reports required in §§ 12.5-651 and 12.5-653 and 40 C.F.R. §§ 403.12(b) and (d), a minimum of four 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 city superintendent may authorize a lower minimum. For the reports required by §§ 12.5-654 and 12.5-654.1 and 40 C.F.R. §§ 403.12(e) and 403.12(h), the industrial user is required to collect the number of grab samples necessary to assess and assure compliance by with applicable pretreatment standards and requirements.
(d) TTOs shall be sampled for as stipulated in each specific federal category. The director may also sample any non-categorical user for TTOs and/or any other parameters reasonably suspected to be present.
(Ord. 12274, § 1, passed 11-28-1995; Ord. 20043-01-2012, § 11, passed 1-10-2012)