(A) Dilution.
(1) Dilution of the effluent from a treatment works or from any wastewater source is not acceptable as a method of treatment of wastes in order to meet the standards set forth herein. Rather, it shall be the obligation of any person discharging contaminants of any kind to the waters of the state to provide the best degree of treatment of wastewater consistent with technological feasibility and economic reasonableness. To determine what kind of treatment is the "best degree of treatment" within the meaning of this division, a person shall consider the following:
(a) What degree of waste reduction can be achieved by process change, improved housekeeping, and recovery of individual waste components for reuse; or
(b) Whether individual process wastewater streams could be segregated or combined.
(2) Measurement of contaminant concentrations to determine compliance with the effluent standards set forth herein shall be made at the point of discharge to the city's wastewater collection system.
(B) Net/gross adjustments. An industrial user may obtain a net/gross adjustment to a categorical pretreatment standard in accordance with the following divisions:
(1) Categorical pretreatment standards may be adjusted to reflect the presence of pollutants in the industrial user's intake water in accordance with this section. Any industrial user wishing to obtain credit for intake pollutants must make an application to the control authority. Upon request of the industrial user, the applicable standard will be calculated on a "net" basis (i.e., adjusted to reflect credit for pollutants in the intake water) if the requirements of division (B)(2) of this section are met.
(2) Criteria:
(a) Either:
1. The applicable categorical pretreatment standards contained in 40 CFR subchapter N specifically provide that they shall be applied on a net basis; or
2. The industrial user demonstrates that the control system it proposes or uses to meet applicable categorical pretreatment standards would, if properly installed and operated, meet the standards in the absence of pollutants in the intake waters.
(b) Credit for generic pollutants such as biochemical oxygen demand (BOD), total suspended solids (TSS), and oil and grease should not be granted unless the industrial user demonstrates that the constituents of the generic measure in the user's effluent are substantially similar to the constituents of the generic measure in the intake water or unless appropriate additional limits are placed on process water pollutants either at the outfall or elsewhere.
(c) Credit shall be granted only to the extent necessary to meet the applicable categorical pretreatment standard(s), up to a maximum value equal to the influent value. Additional monitoring may be necessary to determine eligibihty for credits and compliance with standard(s) adjusted under this section.
(d) Credit shall be granted only if the user demonstrates that the intake water is drawn from the same body of water as that into which the POTW discharges. The control authority may waive this requirement if it finds that no environmental degradation will result.
(C) Sampling. Any user subject to the reporting requirements of this chapter shall submit the results of the sampling and analysis in accordance with 40 CFR 403.12(g). Samples collected to satisfy reporting requirements must be based on data obtained through appropriate sampling and analysis performed during the period covered by the report and data that is representative of conditions occurring during the reporting period.
(1) Except as indicted in divisions (2) and (4) below, the user must collect wastewater samples using 24-hour flow-proportional composite sampling techniques, unless time proportional composite sampling or grab sampling is authorized by the control authority. Where time-proportional composite sampling or grab sampling is authorized by the control authority, 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 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 control authority 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) Samples should be taken immediately downstream from pretreatment facilities if such exist or immediately downstream from the regulated process if no pretreatment exists. If other wastewaters are mixed with the regulated wastewater prior to pretreatment the user should measures the flows and concentrations necessary to allow use of the combined wastestream formula of 40 CFR 403.6(e) to evaluate compliance with the pretreatment standards. Where an alternate concentration or mass limit has been calculated in accordance with 40 CFR 403.6(e) this adjusted limit along with supporting data shall be submitted to the control authority.
(4) For sampling required in support of baseline monitoring and 90-day compliance reports required in § 51.045(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 which historical sampling data does not exist; for facilities for which historical sampling data is available, the control authority may authorize a lower minimum. For reports required by § 51.045(A), the industrial user is required to collect the number of grab samples necessary to assess and assure compliance with applicable pretreatment standards and requirements.
(D) Notice of violation/repeat sampling and reporting. If sampling performed by an industrial user indicates a violation, the user shall notify the control authority within 24 hours of becoming aware of the violation. The user shall also repeat the sampling and analysis and submit the results of the repeat analysis to the control authority within 30 days after becoming aware of the violation. The user is not required to resample if the control authority monitors at the user's facility at least once per month, or if the control authority samples between the user's initial sampling and when the user receives the results of the sampling.
(Ord. 6386, passed 3-20-17)