§ 106-173. Sample types.

(a)

Where representative samples are required to be taken for facilities for which historical sampling data does not exist (or if otherwise requested by the POTW superintendent), a user shall take a minimum of four grab samples for pH, temperature, cyanide, phenols (T), residual chlorine, oil and grease, sulfide, and volatile organics (and any other parameters designated by the POTW superintendent), unless a greater number of grab samples is required in advance by the POTW superintendent. For facilities for which historical sampling data is available, or under other circumstances determined appropriate by the POTW superintendent, the superintendent may authorize a lower minimum number of grab samples. In all cases, users shall take the minimum number of grab samples determined necessary by the POTW to assess and assure compliance by users with applicable pretreatment standards and requirements. Grab samples may be required to show compliance with instantaneous minimum or instantaneous maximum discharge limits. For all other pollutants and sampling, 24-hour composite samples must be obtained through flow-proportional composite sampling techniques, unless time-proportional composite sampling or grab sampling is authorized by the POTW. Where time-proportional composite sampling or grab sampling is authorized by the POTW, 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 & 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 POTW, as appropriate.

(b)

The POTW superintendent may require any user (categorical or non-categorical) to conduct continuous pH monitoring instead of using grab samples. A user required to conduct continuous monitoring will be subject to enforcement under section 106-289(8).

(Ord. No. 2017-5 , § 2, 5-15-17)