§ 51.023  AFFIRMATIVE DEFENSES.
   Pursuant to 40 C.F.R. § 403.5(a)(2), a person discharging wastewater containing prohibited waste to the POTW shall have the following affirmative defenses to the general prohibitions and specific prohibitions set forth above.
   (A)   Upset. An upset shall constitute an affirmative defense to an action brought for noncompliance with categorical pretreatment standards if the following requirements are met.
      (1)   “Upset” defined. For purposes of this section, the term UPSET shall mean an exceptional incident in which there is unintentional and temporary noncompliance with categorical pretreatment standards because of factors beyond the reasonable control of the person discharging wastewater to the POTW; provided, however, that, the term shall not include noncompliance with the general and specific prohibitions set forth above to the extent caused by operational error, improperly designed treatment facilities, lack of preventive maintenance or careless or improper operation.
      (2)   Demonstration of upset. A person desiring 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 person can identity the cause(s) of the upset;
         (b)   The facility was at the time of the upset being operated in a prudent and workmanlike manner and in compliance with applicable and generally accepted operation and maintenance procedures; and
         (c)   The person verbally reported the following information to the Director within 24 hours of becoming aware of the upset and followed the verbal report with a complete written report of same within five days:
            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.
      (3)   Burden of proof regarding defense. In any enforcement proceeding, the person seeking to establish the affirmative defense of upset shall have the burden of proof.
      (4)   Applicability of defense. The affirmative defense of upset shall be available only in an enforcement action brought for noncompliance with categorical pretreatment standards and shall not apply in any other context.
      (5)   Control of discharge pending resolution of upset. A person whose pretreatment system is affected by upset 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. (By way of example and not of limitation, this requirement shall apply in situations where the primary source of power of the treatment facility is reduced, lost or fails.)
   (B)   Compliance with prohibited discharge standards. A person discharging wastewater containing prohibited waste to the POTW shall have an affirmative defense to an enforcement action brought against it for noncompliance with the general prohibitions or specific prohibitions set forth above 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 person 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 person’s prior discharge when the city was in compliance with the permit and the City of Austin was regularly in compliance with its NPDES permit, and in the case of interference, both were in compliance with applicable sludge disposal requirements.
   (C)   Bypass. A person discharging wastewater containing prohibited waste to the POTW may cause, suffer or permit to occur a bypass meeting the conditions set forth in this division (C) and the bypass shall not constitute a violation of the general or specific prohibitions set forth above.
      (1)   “Bypass” defined. The term BYPASS shall mean the intentional diversion of wastestreams from any portion of the wastewater treatment system of a person discharging wastewater containing prohibited waste to the POTW.
      (2)   Conditions for allowable maintenance related bypass. A person discharging wastewater containing prohibited waste to the POTW may allow bypass to occur which does not cause pretreatment standards or requirements to be violated, but only if the bypass is for essential maintenance to assure efficient operation; such a bypass is not subject to the further conditions and limitations of this division (C).
      (3)   Prior notice of anticipated bypass. If the person knows in advance of the need for a bypass, the person shall submit notice of same to the Director at least ten days prior to the date of the anticipated bypass, if possible.
      (4)   Notice regarding unanticipated bypass. The person shall submit verbal 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 report of the bypass 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 requirement of a written report on a case-by-case basis if a complete verbal report has been received within 24 hours.
      (5)   General prohibition of bypass; exceptions. Bypass is prohibited and the Director may take enforcement action against a person causing or allowing a bypass unless:
         (a)   The bypass was unavoidable to prevent loss of life, personal injury or severe property damage; as used herein, the term SEVERE PROPERTY DAMAGE shall mean substantial physical damage to property, damage to the treatment facilities that 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 and shall not include economic loss caused by production delays;
         (b)   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; and
         (c)   The person submits the notices required under divisions (C)(3) and (4) above.
      (6)   Director approval of anticipated bypass. The Director is authorized to approve an anticipated bypass, after considering its adverse effects, if the Director determines that the anticipated bypass meets three conditions listed in division (C)(5) above.
(Ord. 970318A, passed 3-18-1997)