1. Notices of all public hearings held pursuant to this title shall specify the time, date and place of hearing.

2. Service of all processes, except subpoenas, shall be made in the same manner as a summons in a civil action or by registered or certified mail with a return receipt requested, addressed to the individual served in person or in a representative capacity as hereinafter provided at his last known residence, office or place of business. Such service shall be made upon a municipality by serving the chief executive or counsel thereof, upon a sewer district, authority, commission or private corporation by serving an officer thereof, or upon an unincorporated association or partnership or other company of persons, which has a president or treasurer, by serving either of such officers.

3. Subpoenas shall be served upon the witnesses personally, together with such fees therefor as may be provided by law.