The chairman of the Metropolitan Sewer District’s board of directors resigned today Friday.The resignation comes just a week after the Courier-Journal reported that Chairman Audwin Helton’s private company received almost $600,000 dollars in contracts from MSD that were not competitively bid. Louisville Mayor Greg Fischer announced the resignation this morning and requested that two other board members resign as well. Marty Hoehler and Beverly Wheatley also own companies that benefited from contracts with MSD.The mayor appoints members of the board.Fischer is encouraging other local boards and commissions to enact ethics rules to prohibit board members from doing business with the organizations they serve.