Multiple Point Effluent Sampling at the Metropolitan Wastewater Treatment Plant, St. Paul, Minnesota

The concentration time series measured in a sectional model of the Metropolitan Wastewater Treatment Plant (WWTP) dechlorination basin was coupled with field measurements to predict the benefits of mUltiple transverse sampling points. The measured time series was used to generate synthetic time series representing the composite samples from two, three and four sampling points located in a cross section transverse to the flow. The analysis of this data indicates how much the multiple sampling points integrqte transverse gradients, decrease the necessary time to obtain a "representative" sample and decrease the deviation of a 1 second grab sample from a true mean value.