Section 66B. There shall be a board of certification of operators of drinking water supply facilities to insure the proper management, operation and maintenance of public water supply systems. The board shall consist of the commissioner of environmental protection or his designee, who shall be chairman, the commissioner of public health or his designee, the chairman of the water resources commission or his designee and four members to be appointed by the governor. Of the appointive members of the board, one shall be a registered professional engineer engaged in the practice of sanitary engineering, one a member of the Massachusetts Labor Organization, one shall be appointed from a list of qualified operators of water supply facilities in the commonwealth which has been recommended by the executive committee of the New England Water Works Association, and the remaining member shall be appointed from a list of qualified persons recommended by the executive board of the Massachusetts Water Works Association. Each appointive member of the board shall receive his necessary traveling expenses actually incurred in the discharge of his official duties, provided that the expenses of the members of the board, and the expenses of the board, including those of such employees as it may appoint, shall not in any one year exceed its receipts. As the term of office of a member of the board expires, his successor shall be appointed in like manner for a term of four years. Said board shall meet at the call of the chairman and shall by rule establish the minimum qualification which must be possessed by operators of drinking water supply facilities. Said board may prepare and conduct examinations, maintain records and may issue and renew, or suspend or revoke, after hearing and for cause, certification of competency. It may adopt such further rules and regulations not inconsistent with the law as it may deem necessary in the performance of its duties.