Organic matter removal from swine wastewater in constructed wetland with different configurations

This study aimed to evaluate the performance of combined constructed wetland systems (vertical – horizontal flow) in removing organic matter, cultivated with Tifton 85 grass (Cynodon spp.) and cattail (Typha sp.), using pretreated swine wastewater (from anaerobic systems) at variable loading rates. The experimental system was composed of six constructed flooded systems. The flow was frequently monitored by direct measurement, and subsequently, the pH, influent, and effluent concentrations of the variables total solids (TS) and total suspended solids (TSS) and chemical oxygen demand (COD) were determined. The results showed that the average removal of total solids (TS) and total suspended solids (TSS) did not change significantly (p > 0.05) with increasing applied load in vertical flooded systems. While statistically significant differences (p < 0.05) were observed for ST in VFCW3 in Phase III (801–540 mg.L⁻¹, 33%) and for TSS in VFCW2, which showed 48% removal in Phase III (122–62 mg.L⁻¹, 48%), indicating that specific configurations can improve system efficiency. On the other hand, the average removal of total suspended solids (TSS) did not change significantly (p > 0.05) with increasing applied load in horizontal flooded systems. However, the average removal of total suspended solids (TSS) increased significantly (p < 0.05) with increasing applied load in horizontal flooded systems. Therefore, it can be concluded that the COD removal efficiencies, in general, increased with the increase in the applied organic load, reaching approximately 50% (307–271 mg.L⁻¹ VFC3 and 307–145 mg.L⁻¹ HFCW3) for the VFCW-HFCW set.