Wastewater treatment

We provide wastewater discharge service to nearly one third of the Estonian population. In order to ensure compliance with environmental requirements and purity of the Baltic Sea and the Gulf of Finland, Paljassaare Wastewater Treatment Plant removes more pollutants from wastewater each year. The Wastewater Treatment Plant uses environmentally friendly and modern technologies to treat wastewater collected from Tallinn and its surrounding areas.

As a result of investments made in Paljassaare Wastewater Treatment Plant, Tallinn was removed from the list of hotspots (environmentally hazardous cities) determined by the environmental agreement of the Baltic Marine Environment Protection Commission (HELCOM). In 2015, our wastewater treatment parameters were in compliance with the requirements established by HELCOM and those arising from the legislation.

Thanks to our good day-to-day operation, efficient dosing of chemicals and additional treatment stage launched in 2011 (biofilter), we are able to achieve the full compliance of the quality of effluent, discharged from the wastewater treatment plant, with increasingly stricter legislative requirements. Consistent investments and improvements in the existing technological processes are certainly instrumental in maintaining the high standards. As one of such investments, in 2015, we completed the construction of the new coagulant dosing system. Coagulant is a chemical used to remove phosphorus from wastewater. The new dosing system significantly improves both the efficiency and effectiveness of phosphorus removal process in wastewater treatment.

Cleaner living environment

Our focus continues to lie on prevention and reduction of risks related to potential floodings and pollution. The number of blockages is the main indicator of the condition of the sewerage network. Blockages are mainly caused by sediments accumulating in sewage pipes. Lower flow volumes in the network due to decreased water consumption and the continuing extension of the sewerage network are also contributing factors to blockages.

We perform various actions to reduce the number of blockages, among which preventive works are the key. One of such works is the jet washing of sewers, during which a high-speed water flow generated in the network washes all accumulated sediments into the nearest cesspool. Thereafter, sediments are collected by jet washing vehicles and transported to Paljassaare Wastewater Treatment Plant. Jet washing of sewers is carried out by our subsidiary OÜ Watercom, with jet washing vehicles capable of re-cycling the water used in the jet washing process.

Last year we jet washed a total of 155 km of sewerage network and approximately 4,000 storm water inlets. In 2015, a total of 5 km of sewerage network was reconstructed in Tallinn.

More information on the Company’s water and wastewater treatment processes is provided in the 2015 Environmental Report.