Study on the Effect of Microorganisms on Iron and Manganese Removal Efficiency in Low-Temperature Contact Oxidation Treatment

This paper investigates the effect of microorganisms on iron and manganese removal efficiency in low-temperature contact oxidation processes. Low temperatures alter microbial activity and community structure, which subsequently affects iron and manganese removal. A detailed analysis of the microbial community structure at two rural water plants in Liaoning Province, along with a review of relevant literature, clarified the underlying mechanisms of this process. The study examined water quality conditions, microbial communities, and their associations with water quality parameters at each site. Seasonal changes in filter material morphology, oxidation states, and microbial diversity were analyzed to clarify the role of microorganisms in iron and manganese removal, as well as the effects of sand filtration and disinfection on microbial metabolism. Results indicate that Proteobacteria is the predominant bacterial phylum, with Gammaproteobacteria as the dominant class. Gallionella and Flavobacterium were identified as the main functional genera involved in iron and manganese removal. Significant seasonal variations in microbial community composition and structure were observed, particularly in winter, alongside seasonal changes in the manganese sand surface morphology and manganese oxide oxidation states, with Mn(II), Mn(III), and Mn(IV) forms present. Certain microorganisms showed significant associations with water quality parameters, especially in winter, where low-abundance genera such as Rhodoferax, Brevundimonas, Desulfocapsa, and Thiothrix displayed positive correlations with iron and manganese.