Reduction of phosphorus inflow loads and removing its residues is the main issue in protecting waters in rural areas, as by causing eutrophication it largely degrades the function of the aqueous environment [1]. The main sources of mobile phosphorus include water flowing from arable land, residential areas, farms, transport routes, and sewage treatment plants.
It is therefore necessary to seek new methods of further reducing mobile phosphorus concentrations in surface waters. In efforts to find new ways of effective utilization of existing objects in environmental protection, the role of small constructed wetlands in providing additional treatment to flowing waters has been examined. Such objects are of low depth, with intensive water exchange and mixing. These features play an important role in matter transformation. The intensity of biogenic absorption depends mainly on water pollution, ecological condition of the wetland, season of the year, inflowing contamination load and retention time [2].