It is the purpose of this Article to protect the public health and to conserve and protect the quality of the water resources of the State and maintain the quality of receiving waters as assigned by the North Carolina Environmental Management Commission; to protect the public investment in water pollution control systems; to provide for the classification of water pollution control systems; to require the examination of water pollution control system operators and the certification of their competency to supervise the operation of such systems; and to establish procedures for such classification and certification. (1969, c. 1059, s. 3; 1973, c. 1262, s. 23; 1991, c. 623, ss. 1, 3; 1995 (Reg. Sess., 1996), c. 626, s. 6(a).)