Nitrogen and Phosphrous removalfrom municipal wastewater by constructed wetlands

Several physical, chemical, biological methods and combination of them are used for domestic wastewater nitrogen and phosphrous removal. In this study, subsurface horizental constructed wetland with length of 13-6 m, width of 10 m and depth ofO.55m with Phargmites australis is used. Soil porosity was 40 percent. The system irrigated with domestic wastewater. The wastewater COD, TN, TKN and P04 concentration was 300,45-57 and 45-92 mg/l respectively. Hydraulic loading increased from 5 Cm/day to 7.2 cm/d while detention time decreased from 4.2 days to 3 days. Removal percent of COD, TN, TKN and P04= at hydraulic loading equal to 5 cm/d and detention time of 4.2 days was 90,83,94 and 92 percent respectively. The study also indicates that removal percent ofCOD/TN/TKN and P04=at loading of7.2 ern/day was 93,8,86 and 73 respectively