A user shall cause sampling and analysis and reports thereof to be made to the District, of flow and waste characteristics to determine strength and quantity of BOD and TSS under average conditions. Further testing requirements will be as they appear in the discharge permit issued under § 58.107(C).
(A) Samples and measurements shall be representative of the volume and nature of the monitored discharge. Samples shall be taken during normal working hours at the specified monitoring manholes.
(1) Except as indicated in divisions (A)(2) and (A)(3) below, the user shall collect wastewater samples using flow proportional collection techniques, or time proportional collection techniques, if authorized by the Director. Time proportional samples are composed of constant volume aliquots collected at constant time intervals. This method provides representative samples when the wastewater flow does not vary more than 10% of the average flow rate over time. The time proportional sample can be obtained using an automatic sampler, or by the compositing of a minimum of four individual grab samples of the same volume of wastewater, taken during the course of a normal work day.
(2) Samples for oil and grease, temperature, pH, cyanide, phenols, sulfides and volatile organic compounds must be obtained using grab collection techniques. A grab sample can be composed of discrete samples, but all samples must be obtained and combined within a 15-minute time period from start of sampling to finish. When taking a grab sample, the entire mouth of the sample jar must be submerged below the surface of the waste stream. The pH sample should be analyzed immediately and must not be held longer than 15 minutes in any case.
(3) For sampling required in support of baseline monitoring and 90-day compliance reports required in § 58.112(A) and (B), 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 Director may authorize a lower minimum. For the reports required by § 58.112(D), 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.
(B) The Director may use a grab sample(s) to determine non-compliance with any pretreatment standards.
(Prior Code, § 54.53)