Acid Mine Drainage (AMD) is unique acidic wastewater produced in the process of iron mining and utilization. The soil and wetland contaminated by AMD in a mining area in Ma’anshan were studied in this paper. The physical and chemical characteristics and microbial community structure of the samples were analyzed to evaluate the resident soil pollution. The results showed that the soil around the acid reservoir was seriously polluted by metals such as Fe, Mn, Cd, and sulfate, and the loss of organic matter and total nitrogen was serious. With the increased distance between soil samples and the acid reservoir, the pollution degree of AMD decreased, the soil pH, organic matter and total nitrogen contents increased gradually, the soil microbial species increased slightly, and the diversity index increased. Bacillus, Lactococcus, and other bacteria with hydrolytic acid-producing functions accounted for more than 55.0% of the total bacterial community. Desulfuromonas, Desulfobulbus, and other genes involved in sulfur metabolism accounted for more than 24.0% of the total microbial community. In addition, Nitrosophaera, Nitrosopumilus, Methanoregula, and Methanosphaerula, which were involved in nitrogen cycling, were the dominant bacteria in the sampled soil. Our findings provide the basic data to support the mineral industry in China as well as for ecological functional evaluation based on species differences.

A rectangular double chamber with trivalent arsenic as the electron donor of the biological anode was constructed by microbial fuel cells (MFC), and the feasibility of the MFC simultaneous degradation of trivalent arsenic and nitrate was studied. Experimental results show that the co-matrix-coupled MFC reactor oxidizes trivalent arsenic in an anode chamber and degrades nitrate in the cathode chamber. The removal rate of trivalent arsenic is about 63.35%, and the degradation rate of nitrate is about 55.95% during the complete and stable operation period. MFC can continuously output electric energy, and the maximum output voltage is 388 mV. We compared and analyzed the main functional microflora of biofilm microorganisms in an anode chamber. In the long-term arsenic-polluted environment, the activity of Acinetobacter, Pseudomonas bacteria with arsenic resistance, was improved. It is inferred that a fraction of trivalent arsenic was oxidized to pentavalent arsenic by electrode-attached microorganisms. While remaining trivalent, arsenic was taken up by the suspended bacterial biomass and converted into stable arsenide. The results of this study have theoretical reference value for the expansion of the MFC application scope.

The elevated heavy metal concentrations and acidic pH conditions characteristic of Acid Mine Drainage (AMD) pose significant environmental challenges, necessitating the development of effective remediation strategies. This study systematically evaluated the performance of a surface-flow constructed wetland system in Ma’anshan, China, for AMD treatment through comprehensive physicochemical characterization and microbial community analysis. The multi-stage wetland system, comprising four interconnected units vegetated with Phragmites australis, Typha angustifolia, and Arundo donax, was monitored for water quality parameters, sediment characteristics, and microbial diversity. Results demonstrated significant improvements in water quality, with pH increasing from 5.18 to 7.41 and substantial removal efficiencies observed for heavy metals: complete (100.00%) removal of Fe, 92.00% removal of Zn, 61.80% removal of Mn, and 63.60% removal of chemical oxygen demand (COD). Sequential extraction analysis revealed that residual fractions constituted the predominant form of sediment-bound heavy metals (65.70%-70.20% for Fe). Proteobacteria make up 58% of the microbial community. Sulfuricurvum combines denitrification and sulfide oxidation, while SRB like Desulfuromonas convert sulfate to sulfide. Nitrospinae oxidizes ammonia to nitrate, Thaumarchaeota oxidizes ammonia to nitrite, and Parkl vularcula facilitates denitrification. In order to maintain cycles and support wetland function and AMD treatment, hydrolytic bacteria break down organic materials. These findings establish the effectiveness of constructed wetlands (CWS) in AMD remediation through synergistic phytoremediation and microbial metabolic processes, offering an ecologically sustainable approach for the restoration of mining-impacted areas.

Citric acid is a small-molecule organic acid, which can be used as an inhibitor for the flotation of Mg 2+ activated quartz. Methods such as flotation experiments, zeta potential, FTIR qualitative and quantitative calculations, and solution chemistry calculations were used in this study to...