Swine wastewater treatment in constructed wetlands cultivated with Chrysopogon zizanioides e Polygonum punctatum on expanded clay bed

ABSTRACT

The objective of this study was to evaluate the pollutant removal of swine wastewater in horizontal-flow constructed wetlands (CW) and the contribution of vegetable species Polygonum punctatum (smartweed) and Chrysopogon zizanioides (vetiver grass). Three CW's were implanted with expanded clay as support bed, one cultivated with P. punctatum (CW_E), another cultivated with C. zizanioides (CW_V) and one without cultivation, used as control (CW_C). Using a nominal hydraulic retention time (τ) of 3.21 days, theaverage removal efficiencies of BOD, N_T and P_T obtained were 85, 38 e 51% (CW_C), 89, 48 e 69% (CW_E) and 81, 36 e 45% (CW_V), respectively. The best performance was observed on CW_E. The dry mass productivities were 2.79 and 1.91 g m^-2 d^-1. N_T removals were 1.54 and 1.01% and P_T removals were 0.81 and 1.19%, respectively for Polygonum punctatum and Chrysopogon zizanioides .

Keywords:
constructed wetlands; nutrients removal; Chrysopogon zizanioides; Polygonum punctatum