Film and Diffusion Kinetics of Ammonium Removal from Leachate in an Up-Flow Anaerobic Sludge Blanket Reactor

Understanding NH₄ ⁺ removal from leachate mediated by anaerobic sludge (AS) development could lead to the creation of effective, designed biodegradation technologies in the future. This study utilized an up-flow anaerobic sludge blanket (UASB) reactor equipped with a gas-liquid-solid separator to investigate NH₄ ⁺ removal from landfill leachate, enhancing understanding of the biosorption kinetics involved. AS development was initially unstable but progressively improved, exhibiting greater stability with increasing NH₄ ⁺ concentration over the experimental duration. The UASB process performance increased from 15.32 to 63.38% efficiency with an increase in NH₄ ⁺ concentration from 141.71 to 360.59 mg/L. The trend in increased NH₄ ⁺ removal closely mirrored CH₄ production but exceeded COD removal over the experimental duration. The internal mass transfer (IMT) rate variation closely tracked the global mass transfer rate but remained significantly higher than the external mass transfer (EMT) rate, indicating EMT-controlled mass transfer resistance throughout the 197-day experiment. Analysis of NH₄ ⁺ biosorption kinetics in leachate provides new insights into UASB process performance, highlighting the importance of IMT rates, which could inform advanced landfill leachate treatment plant design in the future. Understanding the COD/N/P ratio is crucial for optimizing UASB process efficiency, warranting further research on comparative biosorption kinetics of COD, NH₄ ⁺, and PO₄ ^3- removal from leachate to gain comprehensive insights into landfill leachate treatment.