Photo from U.S. Geological Circular 1225--The Quality of Our Nation's Waters--Nuttients and Pesticides
Photo by Kevin F. Dennehy
Effluent can make up a substantial part of the streamflow in some areas. For example, wastewater treatment plants annually contribute about 69 percent (and at times 100 percent) of the flow in the South Platte River downstream from Denver, Colorado. About 1,200 tons of phosphorus enter the South Platte River Basin every year from wastewater treatment plants.