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Gong X, Zhou Z, Su D, Dong H, Yan L, Ding S, Wang X, Zhang Y. Sulfur-oxygen isotope analysis of SO 42- sources in cave dripwater and their influence on the karst carbon cycle. ENVIRONMENTAL RESEARCH 2024; 240:117508. [PMID: 37890827 DOI: 10.1016/j.envres.2023.117508] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 10/07/2023] [Accepted: 10/24/2023] [Indexed: 10/29/2023]
Abstract
Sulfuric acid is involved in carbonate rock dissolution in karst areas and affects regional hydrogeochemical and carbon cycling processes. Sulfate sources and carbonate weathering at dripwater points of different hydrological types also differ significantly. Therefore, in this paper, three dripwater points (SQ2#, PB and MH6#) of different hydrological types in Dafeng Cave and Mahuang Cave were selected and systematically analyzed. The results show that: (1) ions in the cave dripwater mainly originated from rock weathering, and the water chemistry types were HCO3·Ca-Mg and HCO3-SO4·Ca-Mg. (2) Sulfur and oxygen isotopes reveal that sulfate in the cave water of Shuanghe Cave mainly came from a mixture of soil sulfate and chemical fertilizers. (3) The Simmr model shows that the main sources of sulfate at each dripwater point were natural sources, such as soil sulfate and gypsum dissolution. The natural sources contributed more than 80% of the sulfate in the cave water and were less affected by anthropogenic activities. (4) Carbonate weathering by sulfuric acid (CSW) can accelerate rock weathering and the prior calcite precipitation effect, involving regional CO2 exchange through fissure pipes. The forward model results show that CSW reduced the karst carbon sinks at SQ2#, PB and MH6# by about 19.44%, 23.88% and 12.74%, respectively. Therefore, the impact cannot be ignored in assessing carbon source and sink processes in karst areas.
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Affiliation(s)
- Xiaohuan Gong
- School of Karst Science/School of Geography and Environmental Science, Guizhou Normal University, 550001 Guiyang, People's Republic of China; The State Key Laboratory Incubation Base for Karst Mountain Ecology Environment of Guizhou Province, 550001 Guiyang, People's Republic of China
| | - Zhongfa Zhou
- School of Karst Science/School of Geography and Environmental Science, Guizhou Normal University, 550001 Guiyang, People's Republic of China; The State Key Laboratory Incubation Base for Karst Mountain Ecology Environment of Guizhou Province, 550001 Guiyang, People's Republic of China.
| | - Dan Su
- School of Karst Science/School of Geography and Environmental Science, Guizhou Normal University, 550001 Guiyang, People's Republic of China; The State Key Laboratory Incubation Base for Karst Mountain Ecology Environment of Guizhou Province, 550001 Guiyang, People's Republic of China
| | - Hui Dong
- School of Karst Science/School of Geography and Environmental Science, Guizhou Normal University, 550001 Guiyang, People's Republic of China; The State Key Laboratory Incubation Base for Karst Mountain Ecology Environment of Guizhou Province, 550001 Guiyang, People's Republic of China
| | - Lihui Yan
- School of Karst Science/School of Geography and Environmental Science, Guizhou Normal University, 550001 Guiyang, People's Republic of China; The State Key Laboratory Incubation Base for Karst Mountain Ecology Environment of Guizhou Province, 550001 Guiyang, People's Republic of China
| | - Shengjun Ding
- School of Karst Science/School of Geography and Environmental Science, Guizhou Normal University, 550001 Guiyang, People's Republic of China; The State Key Laboratory Incubation Base for Karst Mountain Ecology Environment of Guizhou Province, 550001 Guiyang, People's Republic of China
| | - Xiaoduo Wang
- School of Karst Science/School of Geography and Environmental Science, Guizhou Normal University, 550001 Guiyang, People's Republic of China; The State Key Laboratory Incubation Base for Karst Mountain Ecology Environment of Guizhou Province, 550001 Guiyang, People's Republic of China
| | - Ye Zhang
- School of Karst Science/School of Geography and Environmental Science, Guizhou Normal University, 550001 Guiyang, People's Republic of China; The State Key Laboratory Incubation Base for Karst Mountain Ecology Environment of Guizhou Province, 550001 Guiyang, People's Republic of China
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Yan X, Gao B, Wang J, Zhu X, Zhang M. Insights into remediation effects and bacterial diversity of different remediation measures in rare earth mine soil with SO 4 2- and heavy metals. Front Microbiol 2023; 14:1050635. [PMID: 37032866 PMCID: PMC10079077 DOI: 10.3389/fmicb.2023.1050635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 02/15/2023] [Indexed: 04/11/2023] Open
Abstract
The increased demand for rare earth resources has led to an increase in the development of rare earth mines (REMs). However, the production of high-concentration leaching agents (SO4 2-) and heavy metals as a result of rare earth mining has increased, necessitating the removal of contaminants. Here, a series of experiments with different remediation measures, including control (CK), sulfate-reducing bacteria (SRB) alone (M), chemicals (Ca(OH)2, 1.5 g/kg) plus SRB (CM-L), chemicals (Ca(OH)2, 3.0 g/kg) plus SRB (CM-M), and chemicals (Ca(OH)2, 4.5 g/kg) plus SRB (CM-H), were conducted to investigate the removal effect of SO4 2-, Pb, Zn, and Mn from the REM soil. Then, a high-throughput sequencing technology was applied to explore the response of bacterial community diversity and functions with different remediation measures. The results indicated that CM-M treatment had a more efficient removal effect for SO4 2-, Pb, Zn, and Mn than the others, up to 94.6, 88.3, 98.7, and 91%, respectively. Soil bacterial abundance and diversity were significantly affected by treatments with the inoculation of SRB in comparison with CK. The relative abundance of Desulfobacterota with the ability to transform SO4 2- into S2- increased significantly in all treatments, except for CK. There was a strong correlation between environmental factors (pH, Eh, SO4 2-, Pb, and Zn) and bacterial community structure. Furthermore, functional prediction analysis revealed that the SRB inoculation treatments significantly increased the abundance of sulfate respiration, sulfite respiration, and nitrogen fixation, while decreasing the abundance of manganese oxidation, dark hydrogen oxidation, and denitrification. This provides good evidence for us to understand the difference in removal efficiency, bacterial community structure, and function by different remediation measures that help select a more efficient and sustainable method to remediate contaminants in the REM soil.
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Affiliation(s)
- Xiao Yan
- GRINM Resources and Environment Tech. Co., Ltd., Beijing, China
- National Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, GRINM Group Co., Ltd., Beijing, China
| | - Bowen Gao
- GRINM Resources and Environment Tech. Co., Ltd., Beijing, China
- National Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, GRINM Group Co., Ltd., Beijing, China
| | - Jianlei Wang
- GRINM Resources and Environment Tech. Co., Ltd., Beijing, China
- National Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, GRINM Group Co., Ltd., Beijing, China
| | - Xuezhe Zhu
- GRINM Resources and Environment Tech. Co., Ltd., Beijing, China
- National Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, GRINM Group Co., Ltd., Beijing, China
- School of Metallurgy, Northeastern University, Shenyang, China
- GRIMAT Engineering Institute Co., Ltd., Beijing, China
| | - Mingjiang Zhang
- GRINM Resources and Environment Tech. Co., Ltd., Beijing, China
- National Engineering Research Center for Environment-Friendly Metallurgy in Producing Premium Non-Ferrous Metals, GRINM Group Co., Ltd., Beijing, China
- *Correspondence: Mingjiang Zhang,
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Li C, Maqbool T, Kang H, Zhang Z. In-Situ Sludge Reduction Performance and Mechanism in Sulfidogenic Anoxic-Oxic-Anoxic Membrane Bioreactors. MEMBRANES 2022; 12:865. [PMID: 36135885 PMCID: PMC9502630 DOI: 10.3390/membranes12090865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/31/2022] [Accepted: 09/05/2022] [Indexed: 06/16/2023]
Abstract
The excess sludge generated from the activated sludge process remains a big issue. Sustainable approaches that achieve in situ sludge reduction with satisfactory effluent quality deserve attention. This study explored the sludge reduction performance of sulfidogenic anoxic-oxic-anoxic (AOA) membrane bioreactors. The dynamics of the microbial community and metabolic pathways were further analyzed to elucidate the internal mechanism of sludge reduction. Compared with the conventional anoxic-oxic-oxic membrane bioreactor (MBRcontrol), AOAS150 (150 mg/L SO42- in the membrane tank) and AOAS300 (300 mg/L SO42- in the membrane tank) reduced biomass production by 40.39% and 47.45%, respectively. The sulfide reduced from sulfate could enhance the sludge decay rate and decrease sludge production. Extracellular polymeric substances (EPSs) destruction and aerobic lysis contributed to sludge reduction in AOA bioreactors. The relative abundance of Bacteroidetes (phylum), sulfate-reducing bacteria (SRB, genus), and Ignavibacterium (genus) increased in AOA bioreactors compared with MBRcontrol. Our metagenomic analysis indicated that the total enzyme-encoding genes involved in glycolysis, denitrification, and sulfate-reduction processes decreased over time in AOAS300 and were lower in AOAS300 than AOAS150 at the final stage of operation. The excess accumulation of sulfide in AOAS300 may inactive the functional bacteria, and sulfide inhibition induced sludge reduction.
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Affiliation(s)
- Chengyue Li
- Institute of Environmental Engineering & Nano-Technology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
- Guangdong Provincial Engineering Research Centre for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Tahir Maqbool
- Institute of Environmental Engineering & Nano-Technology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
- Guangdong Provincial Engineering Research Centre for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Hongyu Kang
- Institute of Environmental Engineering & Nano-Technology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
- Guangdong Provincial Engineering Research Centre for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Zhenghua Zhang
- Institute of Environmental Engineering & Nano-Technology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
- Guangdong Provincial Engineering Research Centre for Urban Water Recycling and Environmental Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
- School of Environment, Tsinghua University, Beijing 100084, China
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