Zinc removal from highly acidic and sulfate-rich wastewater in horizontal sub-surface constructed wetland

Abstract

This study demonstrated the successful utilization of a lab-scale baffled horizontal constructed wetland substituted with mixed organic media for zinc removal from high acidity (∼610 mg L−1 as CaCO3) sulfate-rich (∼1,300 mg L−1) wastewater. The wetland was planted with Typha latifolia. The mean zinc concentration in the influent was gradually increased from 0.56 ± 0.02 mg L−1 to 5.3 ± 0.42 mg L−1. The mean zinc concentration in the outflow was 0.22 ± 0.19 mg L−1, accounting 95% zinc removal throughout the study. However, total zinc uptake by plants was 533 mg kg−1, accounting for only 1.2% of total zinc removal and therefore, major zinc retention occurred within wetland media (83%). The overall activity and specific sulfidogenic activity decreased at the end of the study to 1.43 mg COD removed mg TVS−1 d−1 and 0.60 mg sulfate reduced mg TVS−1 d−1, respectively. Additionally, 16S rRNA sequencing revealed major dominant phyla present: Firmicutes (36%), Proteobacteria (16%), Actinobacteria (8.8%), Planctomycetes (7.8%), Chloroflexi (3.5%), Acidobacteria (1.9%) and Fibrobacteres (1.5%).

Propose the surface flow constructed wetland in the treatment of acid drainage in the closure of a tailings deposit

“…C (2021), in his research we can see that the average removal of Zinc was 97% and 92% during the first phase of treatment. In this investigation, several divisions of the deposit were used in order to find which zone was more efficient to remove zinc [31].…”