3. Results and discussion
3.1. Biomass production in analyzed object
The environmental aspect in the case of constructed wetland systems implementation, apart from sewage treatment, is also the possibility of plant biomass production. Numerous studies confirm that the cutting and removal of the plant biomass from the soil-plant beds has a positive impact for the effectiveness of pollution prevention. It allows the removal of components accumulated during the growing season outside the treatment system. In addition, such a procedure significantly improves the condition of the plants in the next growing season, stimulates more intensive growth, increasing the need and intensity of the components download from waste water (Carballeiraa et al., 2016). The high hydraulic load and the availability of nutrients favors plant production which is comparable to that found on energy crop plantations (Vymazal and Kröpfelová, 2005).
The highest loads of pollutants flowed to bed I planted with common reed (Table 1). Hence, that species had the best growth conditions due to the amount of organic substances supplied with the wastewater. With the flow of the wastewater through the successive beds, the pollutant load decreased. In the wastewater arriving at the final bed the load of nitrogen and phosphorus was 58 g d−1 and 3.1 g d−1, respectively.