The Director, after notice and opportunity for a hearing to a party, may deny, suspend, or revoke a license or permit, or assess a civil penalty, in any case in which he or she finds that there has been a substantial failure to comply with the provisions of this Act or rules established under it. Notice shall be provided by certified mail, return receipt requested, or served personally and by fixing a date, not less than 15 days from the date of such mailing or service, at which time the applicant or license holder shall be given an opportunity to serve a written request for hearing upon the Department. The hearing shall be conducted by the Director or by an individual designated in writing by the Director as the Hearing Officer. On the basis of any such hearing, or upon default of the applicant or license holder, the Director shall make a determination specifying his or her findings and conclusions. A copy of the determinations shall be sent by certified mail, return receipt requested, or served personally upon the applicant or license holder.