(A)   Upset.
      (1)   Per § 57.01 of this chapter, an upset means an exceptional incident in which there is unintentional and temporary noncompliance with categorical pretreatment standards because of factors beyond the reasonable control of the user. An upset does not include noncompliance to the extent caused by operational error, improperly designed treatment facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or improper operation.
      (2)   An upset shall constitute an affirmative defense to an action brought for noncompliance with categorical pretreatment standards if the requirements of subsection (3), below, are met.
      (3)   A user who wishes 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 user can identify the cause(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 user has submitted the following information to the director in writing within 48 hours of becoming aware of the upset:
            1.   A description of the indirect 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.
      (4)   In any enforcement proceeding, the user seeking to establish the occurrence of an upset shall have the burden of proof.
      (5)   Users will have the opportunity for a judicial determination on any claim of upset only in an enforcement action brought for noncompliance with categorical pretreatment standards.
      (6)   Users shall control production of all discharges to the extent necessary to maintain compliance with categorical 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)   Prohibited discharge standards. A user shall have an affirmative defense to an enforcement action brought against it for noncompliance with the general and specific prohibitions in § 57.05 of this chapter if he/she can prove that he/she 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 exists, but the discharge did not change substantially in nature or constituents from the user's prior discharge when the city was regularly in compliance with its NPDES permit, and in the case of interference, was in compliance with applicable sludge use or disposal requirements.
   (C)   Bypass.
      (1)   For the purposes of this section:
         (a)   Bypass shall have the meaning as identified in § 57.01 of this chapter; and
         (b)   Severe property damage means substantial physical damage to property, damage to the treatment facilities which causes them to become inoperable, or substantial and permanent loss of natural resources which can reasonably be expected to occur in the absence of a bypass. Severe property damage does not mean economic loss caused by delays in production.
      (2)   A user may allow any bypass to occur which does not cause pretreatment standards or requirements to be violated, but only if it also is for essential maintenance to assure efficient operation. These bypasses are not subject to the provision of subsections (3) and (4) of this section.
      (3)   (a)   If a user knows in advance of the need for a bypass, he/she must submit prior notice to the director at least ten days before the date of the bypass, if possible.
         (b)   A user shall submit oral notice to the director of an unanticipated bypass that exceeds applicable pretreatment standards within 24 hours from the time it becomes aware of the bypass. A written submission shall also be provided within five days of the time the user becomes aware of the bypass. The written submission shall contain a description of the bypass and its cause; the duration of the bypass, including exact dates and times, 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. The director may waive the written report on a case-by-case basis if the oral report has been received within 24 hours.
      (4)   (a)   Bypasses are prohibited, and the city may take an enforcement action against a user for a bypass, unless:
            1.   The bypass was unavoidable to prevent loss of life, personal injury, or severe property damage;
            2.   There were no feasible alternatives to the bypass, such as the use of auxiliary treatment facilities, retention of untreated wastes, or maintenance during normal periods of equipment downtime. This condition is not satisfied if adequate backup equipment should have been installed in the exercise of reasonable engineering judgment to prevent a bypass which occurred during normal periods of equipment downtime or preventive maintenance; or
            3.   The user submitted notices as required under subsection (3) of this section.
         (b)   The director may approve an anticipated bypass, after considering its adverse effects, if the director determines that it will meet the three conditions listed in subsection (4)(a) of this section.
(Ord. O-99-45, passed 12-1-99)