At Clarion Hospital:  One person was treated for the injuries which he received in a western Clarion County traffic mishap.     Hurt was Charles Manu, who had been driving a tractor-trailer on I-80, east of exit 53, in Beaver Township.     He lost control of his big rig on the snow covered pavement.      The truck veered off of the freeway, first hitting some guardrails, then an overpass pier and finally coming to a stop along the berm.     Aiding, at the wreck site, were Knox fire-rescue and an ambulance crew, as well as Penndot.     The tractor-trailer driver was an Ohio resident.