At approximately 8:20 am, a report was received that protesters were hanging anti-pipeline banners from overpasses in Bismarck.  The Bismarck Police Department responded and located 4 of the protesters involved in this activity.  Two of the protesters were arrested for drug violations and an outstanding warrant.At approximately 4:40 pm, the semi-tractor that has been on the Backwater Bridge in the past 2 days returned to the bridge along with approximately 50 persons.  The semi-tractor and persons eventually left the bridge which was all cleared by 6:00 pm.  No problems were encountered with this group.