Nitrogen and Phosphorus Accumulation in Horizontal Subsurface Flow Constructed Wetland

The article presents the results of studies aimed at determining the level of accumulation of total nitrogen and total phosphorus in parts of reeds (Phragmites australis (Cav.) Trin. ex Steud.), as well as in a constructed wetland bed. The influence of the vegetative phase and dormancy of plants on the level of accumulation of biogenes in plant parts and in the bed of constructed wetland was investigated. Young plants at the stage of intensive growth were found to contain the most total nitrogen and total phosphorus. The leaves of the common reed, on the other hand, revealed the highest ability for the phytoaccumulation of nitrogen (32.21 gN/kg d.m.). Accumulation of total phosphorus in the leaves of reeds was, on average 1.54 gP/kg d.m. The results of studies on the filtration material filling the beds showed that the surface layer of up to 20 cm in depth was characterized by the highest total nitrogen content and total phosphorus content (average: 12.53 gN/kg d.m. and 3.01 gP/kg d.m.). The accumulation of these compounds decreased along with the depth of the deposit as well as in the direction of the outflow of sewage from the constructed wetland.