Pollutants removal effectiveness in hydrophyte filters with sequential vertical and horizontal flow

The performance of constructed wetland composed of sequential reed beds with vertical and horizontal flow of sewage was evaluated, basing on results of concentrations of organic matter, suspended solids and nutrients in inflow and in outflow as well as after subsequent stages of treatment in period 2001–2003. It was proved that dominant role in organic substances removal reaching 98.0% plays vertical flow filter. The removal of phosphorus took place in horizontal flow constructed wetland with efficiency of 36.5%, in vertical flow bed with efficiency 32.9%. Additionally applied adsorption filter removed the rest of phosphorus compounds to the value below 1 mg d−1.Horizontal flow bed secured efficient nitrification of ammonia nitrogen average equal to 81.1% during vegetation season and 93.9% in outside vegetation season. The efficient the denitrification process took place only in 2001 year in horizontal flow constructed wetland with efficiency equal to 0.5 g N day−1 (below project assumptions). In the further time of exploitation colmotation of filling material occurred due to excess load of contaminants from illegal discharge of sewage from individual farms.