Optimized nitrogen removal in low-carbon settings via sequencing batch reactors with vermiculite-enveloped layered double hydroxides bio-fillers

Abstract

This study assesses Mg-Al-LDHs (Layered Double Hydroxides) /VMT (Vermiculite) and Zn-Al-LDHs/VMT as bioreactor packing materials in Sequencing Batch Reactor (SBR) systems for nitrogen removal. The materials were synthesized using a ball milling-hydrothermal method and tested under low-carbon conditions. The study achieved rapid start-up within 24 days, with ammonia nitrogen conversion rates of 77.9 % and 77.3 % for Mg-Al-LDHs/VMT and Zn-Al-LDHs/VMT, respectively, compared to less than 40 % in the control group. The VMT-LDHs bio-filler facilitated the formation of a dynamic film, enhancing biological adherence and adsorption of ammonia nitrogen and dissolved oxygen. This significantly improved the nitrification and denitrification processes. These findings highlight the potential of Mg-Al-LDHs/VMT and Zn-Al-LDHs/VMT to enhance nitrogen removal efficiency in wastewater treatment.