The aerobic vertical flow stage provided high degree of nitrification (removal rate of 4.17 g NH4-N m−2 d−1) while
remaining anaerobic stages (first and third) provided suitable conditions for denitrification (removal
rates of 0.83 g N-NO3 m−2 d−1 and 0.47 g N-NO3 m−2 d−1, respectively). The outflow NH4-N concentrations
were below 5 mg l −1 throughout the monitored period including winter period when the air temperature
dropped below −20 ◦C. Plant biomass sequestered 28% and 26% of phosphorus and nitrogen inflow load,