Optimizing moving bed biofilm reactor performance for complex leachate treatment in urbanizing regions

As urbanization and technological growth accelerate in developing regions, managing mature landfill leachate has become a significant environmental concern due to its complex blend of biodegradable matter, heavy metals. This study investigates a biological treatment approach using a moving bed biofilm reactor (MBBR) seeded with microorganisms derived from landfill soil. At a 30 % carrier filling rate and a 12-h retention time, the system removed 44 % of ammonium and 41.91 % of phosphorus, while chemical oxygen demand (COD) removal averaged below 24.40 %. Improved removal efficiencies 84.14 % for ammonium, 63.17 % for phosphorus, and 78.84 % for COD were observed with increased hydraulic retention time and a 50 % filling ratio. Advanced qPCR analysis identified dominant microbial groups, including Proteobacteria, Bacteroidetes, and Firmicutes, as key drivers of pollutant degradation. The findings highlight the MBBR's robustness and adaptability under variable contamination levels, underscoring its potential as a sustainable treatment strategy for mature leachate in rapidly urbanizing regions.