The authority shall be composed of seven members, who shall be resident electors of either Edgefield or Aiken Counties; provided, however, that no more than two members may be resident electors of Aiken County. Those members of the authority who are resident electors of Edgefield County must be appointed by the Governor, upon the recommendation of a majority of the members of the Edgefield County Council with the approval of the Edgefield County Legislative Delegation. The Governor, upon the recommendation of the members of the Edgefield County Legislative Delegation, may appoint no more than two members of the authority who must be resident electors of Aiken County and who must reside within the service area of the authority in Aiken County. Of those originally appointed, two shall be appointed for terms of two years, two for terms of four years, and one for a term of six years. Upon the termination of the terms of the original members, their successor shall be appointed by the Governor, in the same manner as is provided for the original appointment, for terms of six years. Any vacancy occurring by reason of death, resignation, physical or mental incapacitation, nonattendance, or otherwise shall be filled for the remainder of the unexpired term by appointment of the Governor in the same manner as is provided for the original appointment. Physical or mental incapacitation and nonattendance must be determined by majority vote of board members and with the consent of the legislative delegation. All members of the authority shall hold office until their successors shall have been appointed and shall have qualified.