Each authority created hereunder, whether created by single or multiple localities, shall be governed by a board of not less than six members, but always an even number, appointed by the governing body of the locality. The board members shall be appointed for staggered four-year terms. Members of the governing body may be appointed to the board but shall not comprise a majority thereon. When an authority is created by participating localities, each shall appoint at least two members, one of whom may be a member of the governing body. One-half of the members first appointed by each governing body shall serve for two years and one-half shall serve for four years. After the first appointment, the term of office of all members shall be four years. When one or more additional localities join an existing authority, each of such participating localities shall have not less than two members on the authority’s board. The first members shall be appointed immediately upon the admission of the locality into the authority in the same manner as were the first members of the authority. The members of the board of the authority shall elect one of their number chairman and shall elect a secretary and a treasurer who need not be members of the board of the authority. The offices of secretary and treasurer may be combined. A majority of the members of the authority shall constitute a quorum and the vote of a majority of such quorum shall be necessary for any action taken by the authority. No vacancy in the membership of the board of the authority shall impair the right of a quorum to exercise all the rights and perform all the duties of the authority. Localities which created or thereafter joined the authority, by ordinance or resolution or concurrent ordinances or resolutions, may provide for the payment of compensation to the members of the authority; provided no compensation shall be paid for meetings not attended and for the reimbursement to each member of the authority the amount of his actual expenses necessarily incurred in the performance of that member’s duties.