The Dalles Public Works says operations at the City’s Wastewater Treatment Plant are improving but not yet back in compliance after a recent plant upset that resulted in treated wastewater exceeding the plant’s limit for E. coli being discharged into the Columbia River.  On Sunday samples were taken at pre-arranged locations in the Columbia River to determine the effect of the discharge on water quality in the river.  Tests on five samples show that E. coli levels at the sample locations were well below bacterial criteria set by the Oregon Department Environmental Quality for freshwater recreation.  As a precaution, signs saying “Warning-Contaminated Water-No Water Contact” will remain in place from The Dalles Riverfront to the West Mayer Park boat launch on the Oregon shore of the Columbia.  Wastewater treatment staff are working to restore the biological balance so that the plant can return to normal operations.