A novel fluidized-bed reactor with multi-stage oxygen distribution: Application to toxic and recalcitrant wastewater

The development of efficient and low-energy consumption processes and reactors for the treatment of highly concentrated, recalcitrant, and toxic organic wastewater has been a significant challenge. This study presents a novel fluidized-bed reactor, equipped with multi-stage oxygen distribution zones, designed to enhance detoxification, carbon removal, and nitrogen removal. Experimental investigations using coking wastewater demonstrated that the multi-stage oxygen fluidized-bed reactor achieved COD and TN removal rates of 86.9 ± 1.2% and 93.1 ± 2.7% at a hydraulic retention time (HRT) of 70 h, significantly outperforming the traditional aerobic fluidized-bed reactor (84.4 ± 1.6% and 41.8 ± 2.2%). The multi-stage oxygen distribution in the reactor facilitated the enrichment of various functional microorganisms in activated sludge, leading to the formation of a highly diverse microbial community. This community simultaneously performed organic degradation, nitrification, and denitrification, enhancing the COD degradation and TN removal efficiency in coking wastewater. The fluidized-bed reactor with multi-stage oxygen distribution exhibited performance in treating coking wastewater, offering valuable insights for the design of reactors intended for bio-processing toxic, recalcitrant, and high-concentration industrial wastewater.