The discharge from the City of The Dalles Wastewater Treatment Plant to the Columbia River has returned to compliance with permit limits for E. coli as of Thursday evening.  Samples taken throughout the day on Wednesday at the City discharge point to the river were within limits for each individual sample and for an average of five samples.  The delay in reading out the test results is due to the 24-hour incubation time that the test requires.  Samples taken at pre-arranged locations in the river late in the day on Wednesday were also within limits for each sample.  Signs which were placed at locations of public river access on the Oregon shore of the Columbia River, to warn of contaminated water, were taken down last night.