(8) whether the respondent has successfully completed a Compliance Commitment Agreement under subsection (a) of Section 31 of this Act to remedy the violations that are the subject of the complaint.
In determining the appropriate civil penalty to be imposed under subsection (a) or paragraph (1), (2), (3), (5), (6), or (7) of subsection (b) of this Section, the Board shall ensure, in all cases, that the penalty is at least as great as the economic benefits, if any, accrued by the respondent as a result of the violation, unless the Board finds that imposition of such penalty would result in an arbitrary or unreasonable financial hardship. However, such civil penalty may be off-set in whole or in part pursuant to a supplemental environmental project agreed to by the complainant and the respondent.