In the 2020s, wastewater in the Lappeenranta region will be pumped through new pipelines to a state of the art treatment plant to be constructed in Hyväristönmäki. The water treatment requirements will be Finland’s strictest, on account of the extreme sensitivity of the receiving waters. According to the preliminary plans, the treatment plant will be put into service in 2021, and the environmental permit is expected to be granted this summer.
Mechanical, chemical and biological techniques will be used to treat wastewater.
In December 2015, the Lappeenranta City Council decided on the construction of a new, ultramodern wastewater treatment plant in Hyväristönmäki and the discharge of treated wastewater to Rakkolanjoki. Many surveys were conducted prior to making the decision. The latest of these surveys was a comprehensive environmental impact assessment of six potential locations for the new treatment plant and five potential wastewater discharge points.
Old wastewater treatment plant becomes a pumping station
A new pumping station will be constructed on the site of the existing wastewater treatment plant in Toikansuo, from which wastewater will be pumped through an underground pipeline to the new wastewater treatment plant. Mechanical, chemical and biological techniques will be used to treat wastewater. To ensure the best possible result, the treatment process will include a separate post-treatment.
Water & Environment Director Riitta Moisio notes that on account of the extreme sensitivity of the receiving waters, the wastewater treatment requirements are the strictest in Finland, and also unusually high even by European standard. For instance, the maximum permitted total concentration of phosphorus is 0.1 mg/l.
– The reliability of the transfer system and the treatment plant under all conditions, as well as using the latest and most efficient technology, are therefore emphasised in the planning. Retention and detention ponds are designed for the pumping station to prepare for higher amounts of wastewater and other exceptional situations, and the system’s electricity supply will be ensured through independent emergency power equipment, Moisio concludes.
Follow the construction of the treatment plant via the blog on the website of Lappeenrannan Energia.