A.   Operating Upsets:
      1.   Any user that experiences an upset in operations which places the user in a temporary state of noncompliance with this chapter shall inform the city thereof within twenty four (24) hours of first awareness of the commencement of the upset. Where such information is given orally, a written follow up report thereof shall be filed by the user with the city within five (5) days. An upset shall constitute an affirmative defense to an action brought for noncompliance with applicable pretreatment standards if certain conditions are met. The user that 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 workmanlike manner and in compliance with applicable operation and maintenance procedures; and
         c.   The user has submitted the following information to the city within twenty four (24) hours of becoming aware of the upset (if this information is provided orally, a written submission must be provided within 5 days):
            (1)   Description of the upset, the cause thereof and the upset's impact on the user's compliance status;
            (2)   Duration of noncompliance and, if the noncompliance continues, the time by which compliance is reasonably expected to occur; and
            (3)   All steps taken or to be taken to reduce, eliminate and prevent recurrence of such an upset or other conditions of noncompliance.
      2.   In any enforcement proceeding, the user seeking to establish the occurrence of an upset shall have the burden of proof. Users will have the opportunity for a judicial determination on any claim of upset only in an enforcement action brought for noncompliance with applicable pretreatment standards.
      3.   Users shall control production of all discharges to the extent necessary to maintain compliance with applicable 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 prohibitions in subsections 7-4-4A, B1b, B1e, B1f, B1h and B1l of this chapter 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 exists, but the discharge did not change substantially in nature or constituents from the user's prior discharge when the POTW 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 Provision:
      1.   Users may allow any bypass to occur which does not cause applicable pretreatment standards or requirements to be violated, but only if it is also for essential maintenance to assure efficient operation. These bypasses are not subject to the following:
         a.   If a user knows in advance of the need for a bypass, it shall submit prior notice to the city, if possible at least ten (10) days before the date of the bypass.
         b.   A user shall submit oral notice of an unanticipated bypass that exceeds applicable pretreatment standards to the city within twenty four (24) hours from the time the user becomes aware of the bypass. A written submission shall also be provided within five (5) days of the time the user becomes aware of the bypass. The written description shall contain:
            (1)   Description of the bypass and its cause;
            (2)   Duration of the bypass, including the exact dates and times, and if the bypass has not been corrected, the anticipated time it is expected to continue; and
            (3)   All steps taken or planned to reduce, eliminate and prevent recurrence of the bypass.
         c.   Bypass is prohibited, and the city may take enforcement action against a user for a bypass, unless:
            (1)   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 preventative maintenance; and
            (3)   The user submitted notices as required under subsections C1a and C1b of this section.
      2.   The city may approve an anticipated bypass, after considering its adverse effects, if the city determines that it will meet the three (3) conditions listed in subsection C1c of this section. (Ord. 228, 6-10-2009)