One of the two Horizon Lines freighters that has been idled for many months at the Port of Bellingham’s shipping terminal is departing and heading back into service. The Horizon Consumer, which has been here since May 17, 2009, was scheduled to depart Thursday, Jan. 14, for Tacoma. It will carry freight to and from Alaska in the coming months. It may be back in Bellingham for another long-term stay in fall 2010, a port spokeswoman said.