Treatment of High Nutrient-Loaded Wastewater in a Constructed Floating Wetland with Different Configurations: Role of <i>Lantana</i> Biochar Addition

Constructed wetlands (CW) with carbon stock in substrate matrix show high efficiency in wastewater nutrient removals. In this study, five batch-scale CW setups with varying Lantana weed biochar (BC) doses (5, 10, and 15%) in substrate matrix were established and changes in high nutrient-loaded wastewater parameters, ammonium N (NH4+-N), chemical oxygen demand (COD), nitrate (NO3-N), sulfate (SO4−2), and phosphate (PO4−3), were monitored for 240 h hydraulic retention time (HRT). BC amount directly affected the removal mechanism of CWs and a significant reduction in COD (>92.71%) was recorded. CW setup with a 15% BC dose showed the maximum removal of PO4−3 (79.06%), NH4+-N (78.79%), SO4−2 (67.93%), and NO3-N (77.42%) from wastewater. The theory of BC facilitated physical removal, microbial facilitation, and chemical kinetics improvements are proposed for better removal of wastewater nutrients in studied CWs. Research results could be utilized to design a low-cost domestic wastewater treatment facility using BC for rural areas under a decentralized water treatment program