Operations at the City of The Dalles Wastewater Treatment Plant are improving but are not yet back in compliance after a recent plant upset that resulted in discharge to the Columbia River of treated wastewater exceeding the plant’s limit for E. coli.  Samples were taken on Wednesday at five different locations in the Columbia River to determine the effect of the discharge on water quality in the river.  The five samples taken between River Mile 186.5 and 189.5 show that E. coli levels at the sample locations were well below bacterial criteria set by the Oregon Department of Environmental Quality for freshwater recreation.  City Manager Matthew Klebes emphasized on Thursday E. coli levels are exceeding DEQ limits only within the wastewater treatment plant.  As a precaution, signs will remain in place at locations of public river access until the discharge from the wastewater treatment plant returns to compliance.  Signs are posted on the Oregon shore of the Columbia River, from The Dalles Riverfront Park to West Mayer Park boat launch.