Sustainable Removal of Erythromycin from Wastewater Using LECA and Vetiver in Constructed Wetland Systems: Novel Approach to Antibiotic Pollution Remediation

The contamination of water bodies by antibiotics poses a significant environmental challenge, necessitating sustainable remediation approaches. This study investigated the effectiveness of a vertical-flow constructed wetland (VFCW) integrating lightweight expanded clay aggregate (LECA) and vetiver (Chrysopogon zizanioides) for the removal of erythromycin (ERY) from wastewater. The constructed wetland system was designed to mimic natural wetland processes, utilizing substrate filtration, phytoremediation, and microbial interactions to enhance pollutant removal efficiency. Batch adsorption studies were conducted to optimize key operational parameters, and showed that LECA achieved a maximum sorption efficiency of 90.23%, whereas vetiver root and leaf exhibited removal efficiencies of 71.87% and 87.45%, respectively. Sorption capacity ranged from 1.095 to 1.862 mg/g, and adsorption kinetics were best described by the pseudo-second-order model. Isotherm analysis indicated monolayer adsorption (Langmuir model) for vetiver and multilayer adsorption (Freundlich model) for LECA, with R2 values between 0.97 and 0.99. The optimized parameters from batch studies were applied to a VFCW system, in which LECA alone achieved ERY removal of up to 96.92%. In comparison, including vetiver with LECA further enhanced removal efficiency to 97.6%. The system performed effectively across varying conditions, achieving 95% ERY removal at alkaline pH and 88% removal at 45°C system temperature. The saturated hydraulic conductivity of LECA (1.12×10−3 m/s) facilitated efficient water flow, ensuring optimal wetland operation. These findings highlight the synergistic role of LECA and vetiver as a low-cost, ecofriendly technology in enhancing constructed wetland performance for antibiotic removal.