Performance Intensifications in a Hybrid Constructed Wetland Mesocosm

Abstract

This chapter presents the study on the performance of a hybrid mesocosm constructed wetland system composed of two treatment step: vertical flow bed and floating emergent macrophyte unit (a tank with a vegetated floating mat). The objectives of this study were to assess the performance intensifications in this system by assessing the effect of: (i) combing two types of constructed wetlands, (ii) increasing saturation level in the vertical flow unit, (iii) applying artificial intermittent aeration in the vertical flow unit, on the removal of carbonaceous compounds, nitrogen species and (phosphate phosphorus) P-PO4. The duration of the experiment was 378 days and it was divided into 4 periods: two periods with unsaturated vertical flow bed (but with different hydraulic loading rate values) and two periods with saturated bed of the vertical flow unit (in one period the bed was additionally intermittently aerated). The experimental system was fed with synthetic municipal waste water in a batch mode. It was observed that the intensification of the system’s performance by integrating a vertical flow bed with partly saturated conditions and a floating emergent macrophyte unit ensured high removal efficiencies for total nitrogen (TN) and P-PO4. Additionally, the application of artificial intermittent aeration in a vertical flow bed allowed achieving high removal efficiency of carbonaceous compounds (determined as dissolved organic carbon) without compromising the removal of TN and P-PO4. The scope of further research will include optimization of the system for hydraulic retention time and batch duration and monitoring of the fate of selected micropollutants in the system.