(a) The Commission, with the advice and assistance of the Secretary of Environmental Quality, shall establish grades and types of certification for water pollution control system operators corresponding to the classification of water pollution control systems. The grades of certification shall be ranked so that a person holding a certification in the highest grade is thereby affirmed competent to operate water pollution control systems of that type in the highest classification and any water pollution control system of that type in a lower classification; a person holding a certification in the next highest grade is affirmed as competent to operate water pollution control systems in the next-to-the-highest classification of that type and any lower classification of that type; and in a like manner through the range of grades of certification and classification of water pollution control systems.
(b) No certificate shall be required under this Article to operate a conventional septic tank system. For purposes of this section, "conventional septic tank system" means a subsurface sanitary sewage system consisting of a settling tank and a subsurface disposal field without a pump or other appurtenances.