§ 52.55  AFFIRMATIVE DEFENSES TO DISCHARGE VIOLATIONS.
   (A)   Upset provision. An upset provision shall constitute an affirmative defense to any noncompliance with a categorical pretreatment standard if the requirements of division (A)(1) below are met.
      (1)   Conditions necessary for demonstration of upset. An industrial user who wished to establish the affirmative defense of upset shall demonstrate, through properly signed, contemporaneous operating logs, or other relevant evidence that:
         (a)   An upset occurred and the industrial user can identify the causes(s) of the upset;
         (b)   The facility was at the time being operated in a prudent and workman-like manner and in compliance with applicable operation and maintenance procedures; and
         (c)   The industrial user has submitted the following information to the city within 24 hours of becoming aware of the upset (if this information is provided orally, a written submission must be provided within five days):
            1.   A description of the discharge and cause of noncompliance;
            2.   The period of noncompliance including exact dates and times, or if not corrected, the anticipated time the noncompliance is expected to continue; and
            3.   Steps being taken and/or planned to reduce, eliminate and prevent recurrence of the noncompliance.
      (2)   Burden of proof. In any enforcement proceeding the industrial user seeking to establish the occurrence of an upset shall have the burden of proof.
      (3)   User responsibility in case of upset. The industrial user shall control production of all discharges to the extent necessary to maintain compliance with pretreatment standards. Upon reduction, loss or failure of its treatment facility until the facility is restored or an alternative method of treatment is provided. This requirement applies in the situation where, among other things, the primary source of power of the treatment facility is reduced, lost or fails.
   (B)   Bypass.
      (1)   Generally.
         (a)   An industrial user may allow a bypass to occur which does not violate pretreatment standards or requirements, but only if it also is for essential maintenance to assure efficient operation of its pretreatment facilities.
         (b)   These bypasses are not subject to divisions (B)(2)(a) and (b) below.
         (c)   Any other bypass is prohibited and may result in enforcement action unless, in the determination of the city, all three of the following conditions are satisfied:
            1.   Bypass was unavoidable to prevent personal injury or substantial physical damage to the user’s treatment facilities which would cause them to become inoperable, resulting in a substantial and permanent loss of natural resources which could reasonably by expected to occur in the absence of a bypass;
            2.   There are no feasible alternatives; and
            3.   The industrial user submitted notice as required by division (B)(2) below. The industrial user will be deemed to have had feasible alternatives to the bypass if adequate back-up equipment should have been installed in the exercise of reasonable engineering judgement to prevent by-pass that occurred during normal business periods of equipment down time or preventative maintenance.
      (2)   Notice.
         (a)   If an industrial user knows in advance the need for a bypass, it shall submit prior notice to the city, if possible at least ten days before the date of the bypass.
         (b)   An industrial user shall orally notify the city of an unintentional bypass that exceeds pretreatment standards or requirements within 24 hours of becoming aware of the bypass. A written submission shall also be provided within five days of becoming aware of the bypass. The written submission shall contain a description of the bypass and its cause; the duration of the bypass, including exact times and dates, and if the bypass has not been corrected, the anticipated time it is expected to continue; and steps taken or planned to reduce, eliminate and prevent reoccurrence of the bypass.
   (C)   Compliance with prohibited discharge standards. Excepting the discharge prohibitions set forth at § 52.10(C)(4), (9), (10) and (11), a user shall have an affirmative defense to an enforcement action brought against it for noncompliance with the discharge prohibitions in § 52.10(C) if it can prove that it did not know, or have reason to know, that its discharge, alone or in conjunction with discharges from other sources, would cause pass-through or interference and that either:
      (1)   A local limit exists for each pollutant discharged and the user was in compliance with each limit directly prior to, and during, the pass-through or interference; or
      (2)   No local limit exist, but the discharge did not change substantially in nature or constituents from the user’s prior discharge when the city was regularly in compliance wit the NPDES permit, and in the case of interference, was in compliance with applicable sludge use or disposal requirements.
(Ord. 162, passed 8-12-2002)