Removal and kinetics of basic pollutants in serially constructed wetlands

Abstract

In this research, the spatial distribution and kinetic coefficient of basic pollutants in the artificial wetlands (CW) of the DACBiol-UJAT wastewater treatment plant were evaluated. It consists of a sump-settler and two identical modules with HA in series 8.3 m long, 2.5 m wide and 0.5 m long. In both trains, the first HA is subsurface flow (SSFCW) with Pontederia cordata (tule) species, the second HA is free flow (FFCW) with Thalia geniculata (popal) and the last HAFL with Sagittaria lancifolia (dovetail). The characterization of the support medium, water quality (inlet, outlet and internal points), modeling of the spatial distribution and kinetics of color degradation, turbidity and COD were carried out. Both trains operated with a 3-day HRT with a Qmed of 8.9 ± 3.4 m³/day. The quality of the inlet water of train 1 presents an average turbidity of 72.3 UTN, color of 1340.0 UC and COD with 373 mg/L, likewise at the entrance of train 2 the average turbidity is 69.6 UTN, color of 1,190.3 UC and COD with 373 mg/L. The degradation kinetic constant was estimated in train 1 at -0.52 days^-1 for turbidity, -0.32 days^-1 for color and -0.58 days^-1 for COD, for train 2 of -0.47 days^-1 for turbidity, -0.24 days^-1 for color and -0.49 days^-1 for COD. The removal efficiency for turbidity in train 1 was 65.6% and train 2 was 67.9%, for the apparent color in train 1 it was 48.8% and train 2 was 58.3% and in COD in train 1 it was 81% and for train 2 of 76%. The maximum permissible COD limit according to PROY-NOM-001-SEMARNAT-2017 is met, which is 150 mg/L.