Slide 11 of 100
Notes:
There is a limit to the level of treatment that stormwater ponds and wetlands can provide, sometimes referred to as irreducible concentrations. This concept was originally recognized in process models used to design wastewater treatment wetlands. Essentially, it was determined that wastewater wetlands cannot reduce sediment and nutrient concentrations beyond the rather low levels indicated in the first two columns of data on the slide no matter how much more surface area or treatment volume is provided. The Center�s STP database median effluent concentrations are reported in the fourth column to characterize effluent from STPs.
