Experience in the Use of Constructed Wetlands in Combating "Blooming" of Water in Urban Water Bodies

Using the example of the phyto-purification system (PPS) (Lake Nizhniy Kaban, Republic of Tatarstan, Kazan), its effectiveness in suppressing water bloom, as well as in inhibiting the development of dinophytes and potentially toxic species of blue-green algae, was established. It was confirmed that cattail, calamus and water lily act as effective biofilters. It is concluded that in ponds with macrophytes, the water quality is improved in terms of phytoplankton (the total number and biomass are decreased, the proportion of green and diatom algae in the overall indicators is increased); dominant species causing water "blooming" are suppressed; transparency is increased, the trophic level (biological productivity) of water is decreased; the water quality class is improved from "dirty water" to "clean", from "extremely dirty" to "very clean – quite clean"; the effect of anthropogenic impact on water is reduced. It is recommended to build PPS in coastal zones of urban reservoirs, combining recreational and water treatment functions.