TREATMENT OF NITROGEN AND PHOSPHORUS BY A CONSTRUCTED UPLAND-WETLAND WASTE-WATER TREATMENT SYSTEM

An Upland-Wetland wastewater treatment system was installed in Pamlico County, North Carolina in September 1989 to test its effectiveness in wastewater treatment for a single family home. Treatment effectiveness was evaluated from March 1990 to September 1991. The mound provided an aerobic environment that resulted in complete nitrification and reduction of phosphorus. Concentration of total nitrogen (TN) was lowered 64%, from 44.4 mg/L to 16.0 mg/L by the mound component. Nitrogen in the wastewater dosed into the mound was in the ammonium (NH4-N) and organic forms, while essentially all the nitrogen present in water that had passed through the mound was in the nitrate (NO3-N) form. The mound lowered total phosphorus (TP) concentration 86%, from 4.4 mg/L to 0.6 mg/L. The wetland cell planted with Phragmites australis was more effective than both the unplanted cell and the cell planted with Typha angustifolia. Concentrations of (TN), primarily NO3-N, were lowered from 16.0 mg/L to 11.1 mg/L or of that entering the cell. Total phosphorus was lowered 31%, from 0.6 mg/L to 0.3 mg/L. The Upland-Wetland Wastewater Treatment System has provided low cost, low maintenance and effective wastewater treatment.