ESTONIA'S FIRST POLLUTION-CLEANING FLOATING ISLANDS
are installed on the Soolikaoja ponds formed on headwaters. The islands help reduce hazardous substances in bottom sediments and improve surface water quality.
The seven-and-a-half-kilometer-long Soolikaoja originates from the underground springs of the Vinni Mountains and initially flows through an underground nitrate-sensitive area with intensive agricultural activity so the water is already high in nitrates and total nitrogen before reaching the city. Soolikaoja is also part of the Rakvere stormwater drainage system and stormwater carries additional pollution into the stream.
Samples taken from the stream show significantly higher than normal levels of nitrogen and phosphorus in the water which causes vegetation to proliferate in the upstream swollen ponds and has created lake-like living conditions.
Phytoremediation techniques, i.e. plant remediation are used to reduce the content of hazardous substances in the sediments of the ponds and to improve the quality of surface water.
11 floating islands with a total area of 170 square meters have been built on the ponds of Rakvere city. Green plants and microorganisms decompose harmful pollutants in water. Cotton grass, bulrush (Typha plants) and various irises are planted on the floating islands. These plants need a lot of water and consume pollutants from the water with the help of their roots.
The plant remediation solution works passively and as a bonus the islands offer new habitats for aquatic life and nesting sites for birds. In addition to effectively removing contaminants from the water floating islands also shade the water helping to regulate water temperature and limit the amount of sunlight to prevent algal blooms.
LIFE IP CleanEST is an integrated water management project focusing on improving the status of water bodies in Ida-Viru County and Lääne-Viru County. The project covers a total of 240,000 hectares, covering a total of 574 km of watercourses and nearly 160,000 hectares of coastal water bodies.