Performance of lab-scale tidal flow constructed wetlands treating livestock wastewater

摘要

The body of knowledge on the performance of tidal flow constructed wetlands treating strong wastewaters like livestock wastewater is insufficient. Experiments on three laboratory-scale tidal flow constructed wetlands with different operational strategies were carried out to investigate the performance, regarding the removal of organic matter, nitrogen and phosphorus in livestock wastewater. Results demonstrated that the removal of total organic carbon averaged about 70% under varying influent concentration. The findings demonstrated a change from 290 mg/L to 1500 mg/L in three wetlands with flood drain ratios of 1 h:3 h, 3 h:3 h, 6 h:6 h, respectively. There was no significant difference in TOC removal between the experimental phases with different organic load and flood drain ratio. The removal of ammonium was particularly impactful to the flood drain ratio with results that achieved 59% (flood drain ratio 1 h:3 h), 65% (3 h:3 h) and 71% (6 h:6 h), respectively. The presence of nitrate (180 mg/L) in the effluent indicated enhanced nitrification process in tidal wetland due to its high capacity of oxygen transfer. The removal of phosphorus was exhibited to be 35% which was mainly adsorbed to the matrix.