A user shall have an affirmative defense to an enforcement action brought against it for noncompliance with the general prohibitions in §
192-73A of this part or the specific prohibitions in §§
192-73B(3) through
192-73B(7) of this part 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:
A. 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
B. No local limit exists, but the discharge did not change substantially
in nature or constituents from the user's prior discharge when the
Borough was regularly in compliance with its NPDES permit, and in
the case of interference, was in compliance with applicable sludge
use or disposal requirements.