Today, the Minister of the Environment introduced a research which offers specific measures for clearing the air near the Russalka and Pirita.
"The main point is, we now know the solution that helps to clear the air near the Russalka and Pirita - most reasonable seems to be establishing of deep water encumbrance. We in the Ministry of the Environment are prepared to finance the solution for this issue disturbing inhabitants of Tallinn. The work can be undertaken immediately after technical work, impact assessments and preparations are done," the Minister of the Environment Keit Pentus-Rosimannus said.
According to a survey carried out by the Marine Systems Institute at Tallinn University of Technology, the smell in Pirita and Merivälja is caused by rotting algae at the shore. Water, which arrives to the sea through release openings of rainwater and from the river of Pirita, is very rich in nutrients and leads to mass growth of algae. No residual pollution at the bottom of the sea was found.
Scientists offered five solution variants: leading rainwater to the deep sea, mechanical removal of the algae and leading rainwater to common sewerage, cleaning of rainwater and chancing coastline.
"Long-term solution is important for us. Thus, annual mechanical cleaning of seafloor is not reasonable. The best possible solution seems to be the establishment of rainwater release opening that reaches deep in the sea. Now, we shall quickly proceed with expenditure calculation for all four alternatives and impact assessments and by the end of the year we expect more detailed operating plans," the Minister of the Environment Keit Pentus-Rosimannus said.
According to modelling devices, leading rainwater into the deep water encumbrance does not result in significant increase in nutrient pollution because of the gulf bathymetry and the main wind direction nutrients move into the open sea.
During the investigation, sediment samples from the seafloor were taken in order to clarify the input data needed for modelling and possible residual pollution. Additionally, phosphorus and nitrogen concentration of nutrients of the water of the Gulf of Tallinn were measured and for rainwater release openings. After that, surface waters and rainwater flow into the Gulf were evaluated and nutrient flow were calculated and modelled.
The project was funded by the Environmental Investment Centre Foundation.