New land use in the plots of the existing wastewater treatment plants
In addition to wastewater generated by Tampere, wastewater generated by Kangasala, Pirkkala, and the inner city of Ylöjärvi are also currently being treated in wastewater treatment plants in Tampere. The sewer network that covers Lempäälä and Vesilahti is connected to the Lempäälä wastewater treatment plant. The three current wastewater treatment plants are reaching the end of their technical lifespan and are in need of major renovations.
The current wastewater treatment plants are located in valuable shore areas surrounded by existing community structure. Once the new central wastewater treatment plant is complete, their plots will enable significant infill development planning in both Tampere and Lempäälä.
The treatment plant will be an active sludge plant based on simultaneous precipitation, where wastewater is treated mechanically, chemically, and biologically. The wastewater treatment process includes the following phases: racking, aerated sand removal, primary sedimentation, active sludge process dimensioned for total nitrogen removal, secondary sedimentation, and sand filtration as post treatment. Treated wastewater is disinfected by UV radiation. Anaerobic treatment (decomposition) has been selected as the sludge treatment solution. Sludge is decomposed in bioreactors by means of bacteria that act in anaerobic conditions. The process produces water, carbon dioxide, and biogas. Biogas is used for running gas engines that produce nearly 60% of the electricity and 90% of the heat needed by the treatment plant each year.
Wastewater transfer systems
The required wastewater transfer systems will be implemented inside the rock at the same time with the wastewater treatment plant. These include two pumping stations, a sewage tunnel for leading wastewater to the treatment plant, and a discharge tunnel for leading the treated wastewater into the discharge pipe, and a transfer sewer network to street and road areas and the water system.