###### Abstract  
The stream sediments that have been impacted by manganese (Mn) containing wastewater for decades contain not only abundant microorganisms but also organic/inorganic substances. To achieve effective treatment of manganese (Mn)-containing effluent and recovery of Mn from water/sediments, the Mn(II) sorption behaviors and mechanism on sediments of a stream in Mn mining areas were studied. In addition, the study analyzed the effects of various factors (initial concentration, solution pH, sediment dose, contact time, and coexisting cations) on the Mn sorption efficiency of Daxin sediments, and explored the contribution of microbial activity in the sediment sorption of Mn(II). The results showed that the sorption process of Mn(II) on the sediments was consistent with the [PERSON] and Freundlich models, and the removal of heavy metals was maximum at 40 \({}^{\circ}\)C (62.47-98.93%), pH = 8 (77.51%), initial concentration of 1 mmol-L- (95.37%) and sediment dosing of 12 g-L-1 (98.93%). The addition of 50 mM NaN\({}_{3}\) inhibited the microbial activity in the Daxin sediment, reducing the sorption and removal rates of Mn(II) by 0.605 mg\(\cdot\)g\({}^{-1}\) and 8.92%, respectively. After sorption, the proportion of the Fe-Mn oxidation(iron-manganese) state in Daxin sediments decreased from 54% to 43%, while the proportion of the exchangeable state increased by 10.80%. Microorganisms in the sediment had a positive effect on inhibiting heavy metal migration and reducing the bioavailability of contaminants in the soil. Through this study, we hope to further understand the sorption and desorption mechanism of manganese by stream sediments in manganese ore areas, so as to provide a guide on the management and recovery of Mn from stream sediments in manganese mining areas. manganese mining area; sediment; manganous; sorption 20222123368. 2022123368.  
extremely fragile and more vulnerable to Mn contamination in surface water as well as groundwater than other regions [9]. Conventional wastewater treatment systems can remove most pollutants, but they do not fully achieve effective removal of large amounts of manganese and ammonia nitrogen, even after standard treatment. Existing processes still have shortcomings such as complexity and high costs, and some processes produce by-products that can even lead to secondary pollution [10]. Constructed wetland (CW) is recognized as the most economical and green technology to intercept such pollutants through plant extraction and microbial stabilization/mineralization. Constructed wetlands use soil, vegetation, and microbial communities to mimic the main structures of natural wetlands. The mechanism of CW treatment of wastewater involves chemical, biological, and physical processes such as sedimentation, filtration, precipitation, volatilization, sorption, plant uptake, and microbial degradation [11; 12; 13]. As a carrier for biofilm development in nature, a medium for wetland plant growth, and an adsorbent for pollutant immobilization, river sediments can effectively adsorb heavy metals and other pollutants in the sediment [14]. Microorganisms, especially manganese-oxidizing bacteria, play a crucial role in the purification of metallic Mn and the uptake of NH\({}_{4}\)\({}^{+}\)-N. The removal of NH\({}_{4}\)\({}^{+}\)-N depends mainly on the nitrification/denitrification capacity of microorganisms, while the enrichment of inter-rooted microorganisms and ferromanganese oxides contributes to a large extent to the removal of NH\({}_{4}\)\({}^{+}\)-N [15; 16; 17]. Therefore, it is essential to explore the effect of sediment as well as microbial activity on manganese sorption in manganese mining areas during the construction of constructed wetlands. River sediments are complex mixtures of clays, silica, natural organic matter, aluminum, iron and manganese oxides, carbonates, sulfides, certain minerals, and bacteria [18]. As the \"sink\" of manganese, sediment is not only the final home of manganese but also the place where manganese begins its geochemical cycle.