Why calculate the destruction and removal efficiency (DRE) for a constituent that is below the detection limit in the effluent?
The PFPR regulation does not require facilities to calculate the DRE of pesticide active ingredients or priority pollutants; however, it may be helpful to determine which treatment units in a treatment train are providing significant removal of the constituents of interest. For example, the following table summarizes the removal of a constituent through a treatment system consisting of hydrolysis and activated carbon. The DRE shows that even though activated carbon removes the constituent to below detection (i.e., µg/L), the hydrolysis unit achieves the majority of the constituent’s reduction (i.e., 98 percent).
