ROLE OF VEGETATION IN THE FUNCTIONING OF A CONSTRUCTED WETLAND FOR WASTEWATER TREATMENT

Constructed wetlands have been used for wastewater treatment for several years, since their natural processes effectively contribute to the removal of pollutants. During our survey, we examined an artificial wetland, which was constructed for the treatment of petrochemical wastewater. The treatment system has been studied by the Department of Applied Ecology of the University of Debrecen for more than thirty years. Besides examining of the effectiveness of pollutant removal in the system, the ann of our work was to reveal the role of vegetation in the functioning of the wetland-system. According to our results, concentration values of various nitrogen-forms (i.e. nitrite, nitrate and ammonium) suggest some kind of inhibition in the process of nitrification. Removal rates of BOD and COD were 40 and 51 respectively, which are considered to be satisfactory as well as the removal of phosphorous, since 21 per cent of total phosphorous was retained in the wetland.