Potential of Canna indica in Vertical Flow Constructed Wetlands for Heavy Metals and Nitrogen Removal from Algiers Refinery Wastewater

Abstract

Constructed wetlands (CWs) are important plant filters used for wastewater treatment. The behavior of the Canna indica-planted CWs in the face of a highly variable composition of industrial wastewater has yet to be understood. Here, we show the effectiveness of Canna indica-planted and unplanted vertical subsurface flow CWs for the treatment of Algiers petroleum refinery’s effluent. The selected species was placed in the CWs containing light expanded clay aggregate (LECA) and sand as a substrate. The findings indicate that the planted constructed wetlands efficiently removed 85% of total suspended solids (TSS), 96.38% of total nitrogen (TN), 96.15% of nitrate nitrogen (NO3−-N), 99.15% of ammonium nitrogen (NH4+-N), and 99.87% of nitrite nitrogen (NO2−-N). The overall mean removal efficiencies for heavy metals in the vegetated CWs were considerably greater than those of the control. Concentrations of Cr, Cu, Fe, Pb, Zn, Al, Ni, and Cd were calculated in the roots, rhizomes, leaves, and stems of the plant; then, the bioaccumulation factor (BAF) and translocation factor (TF) were determined. An initial examination using scanning electron microscopy (SEM–EDX) was also included in the study. The analysis indicated that toxic elements were adsorbed on plant tissues, concentrated in the roots, and partially transported to the aerial parts. These results are useful for the design of CWs to treat industrial wastewater, enabling water of acceptable quality to be discharged into the environment, especially as a low maintenance and cost-effective technology in developing countries.

Proposing a Wetland-Based Economic Approach for Wastewater Treatment in Arid Regions as an Alternative Irrigation Water Source

“…Reduced pollution was mostly caused by the plants. Utilizing plants served four key purposes including the filtration of suspended particles, bacterial development, oxygen uptake by the plant roots, and substrate maintenance [55]. The soil in the constructed wetlands played a role in lowering pollution.…”

Recruitment and metabolomics between Canna indica and rhizosphere bacteria under Cr stress

“…Canna indica is a perennial herbaceous plant with a large leaf area, developed root system, and strong adaptability to the growing environment (Luo et al, 2022a , b ). C. indica is effective in heavy metal adsorption and nitrogen removal in constructed wetlands and significantly contributes to heavy metal adsorption capacity and soil fertility after airbrushing mycorrhizal fungi (AMF) colonization (El Faiz et al, 2015 ; Ghezali et al, 2022 ). However, the effects and mechanisms of differentially expressed metabolites on rhizosphere-related microbial communities under heavy metal stress still need further study.…”