Nutrient removal in floating and vertical flow constructed wetlands using aluminium dross: An innovative approach to mitigate eutrophication

• Published in: Bioresource technology Vol. 410; p. 131205
• Main Authors: Mittal, Yamini, Srivastava, Pratiksha, Kumar, Naresh, Tripathy, Bankim Chandra, Martinez, Fernando, Yadav, Asheesh Kumar
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2024
• Subjects: Adsorption; Alginates - chemistry; Aluminum - chemistry; Ammonium Compounds; Ca-Alg-Al dross beads development; Constructed wetlands; Eutrophication; Lentic ecosystem remediation; Nature-based wastewater treatment; Nutrients; P recovery; Phosphates - chemistry; Wastewater - chemistry; Water Pollutants, Chemical; Water Purification - methods; Wetlands; Lentic ecosystem remediation; Adsorption; Constructed wetlands; Ca-Alg-Al dross beads development; P recovery; Nature-based wastewater treatment; Eutrophication
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2024.131205

[Display omitted] •Aluminium dross beads enhance practical utility of raw aluminium dross.•Efficiently removes pollutants from both flowing and stagnant water environments.•Maximum phosphate and ammonium removal achieved were 85 % and 93 %, respectively.•Treated water can prevent algal growth, ensuring safe water discharge. On global scale, eutrophication is one of the most prevalent environmental threats to water quality, primarily caused by elevated concentration of nutrients in wastewater. This study utilizes aluminum dross (AD), an industrial waste, to create a value-added material by improving its operational feasibility and application for removing phosphate and ammonium from water. The operational challenges of AD such as its powdered nature and effective operation under only extreme pH conditions were addressed by immobilizing in calcium alginate to form calcium alginate aluminium dross (Ca-Alg-Al dross) beads. These Ca-Alg-Al dross beads were further tested for phosphate and ammonium removal from natural wastewater in two different aqueous environment systems: (i) vertical flow constructed wetlands (VF-CWs) followed by Ca-Alg-Al dross beads fixed bed system and (ii) Ca-Alg-Al dross beads mounted floating constructed wetlands (FCW) for remediating polluted lentic ecosystems. Our results show maximum phosphate and ammonium removal of 85 ± 0.41 % and 93.44 %, respectively, in VF-CWs followed by Ca-Alg-Al dross beads fixed bed system. The Ca-Alg-Al dross beads mounted FCW system achieved maximum phosphate removal of 79.18 ± 8.56 % and ammonium removal of 65.45 ± 21.04 %. Furthermore, the treated water from the FCW system was assessed for its potential to inhibit algal growth by artificially inoculating treated water with natural algae to simulate eutrophic conditions. Interestingly, treated water from the FCW system was found capable of arresting the algal growth. Besides, scanning electron microscopy with energy dispersive X-ray (SEM-EDX) and Fourier transform infrared (FTIR) spectroscopy confirmed the functional groups and surface properties and probable participation of multiple mechanisms including ion exchange, electrostatic attraction, and ligand complexation for phosphate and ammonium removal. Overall, these results offer a promising way to utilize AD for high-end applications in wastewater treatment.